Orthognathic surgery by almuzian

Surgical Orthodontics, Corrective Jaw Surgery or Orthognathic Surgery

Definition

The correction of the functional and aesthetic consequences of severe dentofacial

deformity through a combination of orthodontic, surgical and possibly restorative

dentistry

Aims

A satisfied patient.

Improve facial aesthetics

Improve dental aesthetics

A functional, balanced and stable occlusion

Optimal oral and related health

History

Trauner and Obwegeser introduced the sagittal split ramus osteotomy in 1959.

In 1960s development by Bell, Epker and Wolford of the LeFort I technique.

In the 1990s, rigid internal fixation greatly improved the surgical result and increase

patient comfortibility

Prevalence

IN UK according to O’Brien 2009, the prevalence of jaw’s surgery is as follow:

1. Gender and age distribution

Mean age 22y

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More female

2. Malocclusion

45% class 2

43% class 3

12% AOB

3. Type of surgery

66% bimax

24% mand surgery only

10% max surgery only

4. Continuation & duration of treatment

28% overall didn't complete treatment

Mean duration of treatment 45 months

Timing and sequencing of surgical treatment

A. Usually all operations should be delayed until the completion of growth

B. Early treatment

Indications

1. P sychosocial considerations

2. Mandible problems

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Early mandibular advancement for sever mandibular retrognathia can be done since most

of postsurgical growth is expressed vertically, there is no reason to delay mandibular

advancement after sexual maturity

Rib grafts in craniofacial microsomia cases

Class II due to condylar ankyloses

Breathing problems

Facial asymmetry to avoid compensatory mal-development of the maxilla

3. Maxilla problems

In general, maxillary advancement should be delayed until after the adolescent growth

spurt unless there are preponderant psychological considerations. In this case, subsequent

growth of the mandible is likely to result in reestablishment of the abnormal

relationships, and the patient and parents should be cautioned about the possible need for

a second stage of surgical treatment later

No early surgery for vertical excess because vertical growth continues

General Indications of Orthognathic treatment

The cases that can be corrected by OS include:

Severe CI 3

Severe CI 2

Long face syndrome/AOB

Facial asymmetries

Chin abnormalities

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Craniofacial anomalies e.g. CLP

However, the indications of OS are:

1. Facial aesthetics

Pre-treatment assessment of orthognathic patients found that less than 50% patients

were unhappy with their pre-treatment facial aesthetics (Cunningham et al 1996).

About 90% of patients who undergo orthognathic surgery report satisfaction with the

outcome and over 80% say they would recommend such treatment to others and would

undergo it again (Cunningham et al 1996).

Hunt et al 2001 in systematic review, he concluded that orthognathic patient

experience psychological benefits as a result of orthognathic surgery including improved

self-esteem, body and facial image, and social adjustment.

Sammaan in HK in 2010 found that the quality of life (QoL) didn't improve before

surgery but only immediately after surgery. While the oral health quality of life impact

OHQoO had been dropped in the decompensation phase and then improved after surgery.

2. Dental aesthetics which cannot be addressed orthodontically

In a study of pre-treatment orthognathic patients, 72% were unhappy with their teeth

(Cunningham et al. 1996). OS is indicated when:

Orthodontic treatment alone might cause determinately effect on the facial and

occlusal aesthetic as well as PD compromization

In non-growing patients when growth modification is not applicable

Too severe for orthodontics alone

Presence of complete compensation

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Presence of sever crowding that might use the whole extraction space leaving nothing

for more compensation by orthodontic means.

Sever vertical or transverse problem

3. Masticatory function

Speech problem like lisping in AOB

Anterior open bites with chewing problems

NB: Evidence suggests that there is a change in the bite force experienced by many post-

operative patients. Work by Hunt and Cunningham (1997) found that when mandibular

advancement was undertaken for reduced patients face height, the bite forces reduced in

the post-surgical phase. Conversely, in long face patients who underwent bimaxillary

surgery the bite force increased.

New index called IOFT was developed by Ireland et al in 2014. A panel of four

consultant orthodontists, experienced in providing orthognathic care, devised a new index

of Orthognathic Functional Treatment Need (IOFTN) with the aid of the membership of

the British Orthodontic Society Consultant Orthodontists Group (COG). Twenty-three

consultants and post-CCST level specialists took part in the study as raters to test the

validity and reliability of the new index. The study proved that the IOFTN, demonstrates

good content validity and good inter-rater and moderate to good intra-rater reliability.

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4. Airway In a few centres in the UK and in North America, orthognathic surgery may be

performed to increase the airway in patients with obstructive sleep apnoea.

5. TMD This is an area of controversy. The evidence suggests we should warn all

patients that they have a 20% risk (approximately) of developing TMD post-op but for

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those who have TMD pre-op, a percentage may improve, other will stay the same or a

small number may worsen.

6. Periodontal indications: especially in deep OB when it is traumatic and cannot be

addressed by conventional orthodontics. Complete overbiter may suffer trauma to the

palatal or labial gingivae.

7. Prosthetic indications like a case of sever attrition in which the prosthetic restorations

are impossible without increasing the VH by surgery.

Contraindications &/or limitations

Growing patient

Minor cases

Medical condition

Psychologically unstable patient

Parameters indicators or Yardsticks for orthognathic surgery

1. For class II

Proffit 1992

OJ 10mm

ANB > 9°

Pog posterior to N perpendicular 18mm

Mandibular length less than 70 mm

Lower anterior facial height more than 125mm

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Squire et al., 2006:

Positive overjet greater than 8mm,

A transverse discrepancy greater than 3mm were not considered to be orthodontically

treatable

Mihalik et al., 2003

A study at the University of North Carolina compared the long term outcomes of

orthodontic camouflage and orthognathic surgery for adult Class II patients (Mihalik et

al., 2003). Thirty-one adult patients were treated with orthodontic camouflage alone and

118 treated with an orthognathic approach. Patients were very pleased with outcomes

from both orthodontic camouflage and orthognathic treatment. The orthodontic

camouflage patients reported fewer functional or temporomandibular joint problems than

the orthognathic patients. The patients who had undergone a mandibular advancement

were significantly more positive about their dentofacial images.

Ruf and Pancherz, 2004

A later study compared the treatment outcomes in adult Class II patients treated with

mandibular sagittal split osteotomy versus the Herbst appliance (Ruf and Pancherz,

2004). Forty six patients were treated with orthodontics and a sagittal split osteotomy

compared with 23 patients treated with a Herbst appliance. Both groups were

successfully treated to a Class I occlusion. In the orthognathic group the changes which

occurred were by skeletal movement rather than dental; in the Herbst group the opposite

was the case. In both groups the skeletal and soft tissue profile convexity reduced

significantly, but the reduction in soft tissue convexity was greater in the orthognathic

group. The authors concluded that Herbst treatment can be considered as an alternative to

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orthognathic treatment in the adult Class II Division 1 malocclusion when facial

improvement is not the main treatment goal.

2. For class III

1. Squire et al., 2006:

A negative overjet of -4mm or greater,

A transverse discrepancy greater than 3mm were not considered to be orthodontically

treatable

2. Stellzig-Eisenhauer et al (2002)

A more recent study examined this area further: 87 Class III patients received

orthodontic treatment and 88 patients were treated with surgery. Discriminant analysis

was used to classify patients into non-surgery and surgery groups; the most significant

variables were Wits appraisal, S-N (length of anterior cranial base), M/M ratio (ratio of

antero-posterior length of maxilla to the antero-posterior length of the mandible) and

lower gonial angle:

-1.805 + (0.209 x Wits) + (0.044 x S-N) + (5.689 x M/M ratio) - (0.056 x Gonial angle)

The critical score was -0.023, which means that a patient score higher than the critical

score could be treated successfully by orthodontic therapy alone.

1. Kerr et al 1992

ANB = -4°;

maxillary mandibular ratio = 0.84 ,

lower incisor inclination (LI/MP = 83°)

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Soft tissue profile (Holdaway angle = 3.5°)(soft tissue nasion-soft tissue pogonion

labrale superius). Interestingly, vertical dimension had little influence on treatment

decision.

The management protocol for facial deformity

1. History

2. Clinical examination

3. Psychological assessment

4. Investigations

5. Clinical and radiographical examination.

6. Initial diagnosis

7. Initial Treatment plan

8. Presurgical orthodontics

9. Final treatment plan

10. Surgery

11. Postsurgical orthodontics

12. When appropriate, restorative dentistry, psychological intervention and speech

therapy will be required.

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In details

History and patient assessment

1. Age and sex - influences amount of growth remaining

2. Race - influences profile considerations

3. PDH: To identify the cause (family trait, congenital deformity, or trauma in infancy or

adolescence)

4. CC: To identify the main CC in order of priority

5. MH: medical disorders, which require specific attention include:

Haemophilia or clotting disorders which require pre-and intraoperative management

Rheumatic or congenital heart valve lesions

Acromegaly patients may be a cardiomyopathy risk

Obstructive sleep apnoea should warrant a sleep study and specific assessment.

Antibiotic or analgesic idiosyncrasy or allergy

Psychological assessment

See Almuzian notes about Psychology in orthognathic patients

Investigations for OG cases

A minimum dataset for orthognathic patients has been jointly agreed between the BOS

and BAOMS. The datasheet was designed to rationalise which records should be taken

during orthognathic treatment. An obvious development in this area is then to develop a


local or regional database; this does however require NHS Research Ethics Committee

(NRES) approval (Morris, 2006).

1. Lateral Cephalograms

Pre-orthodontic lateral cephalograms is essential for treatment planning

Pre-surgical phase lateral cephalograms is essential for treatment planning

An immediate post-operative lateral cephalogram should not be taken routinely. Only

take in concern cases, where the post-surgical maxilla position is in question and a quick

return to theatre is likely. The request for a lateral cephalogram taken at 1-3 weeks post-

surgery should be under the direction of the orthodontist. Any surgical wafer used should

be removed prior to this x-ray exposure and it should be carried out on the same

cephalostat as previously used. The teeth should be in occlusion with much of the post-op

swelling subsided. This view will record a true and meaningful post-op position of the

jaws prior to significant postsurgery orthodontic mechanics, such as intermaxillary elastic

traction, commencing. In units using IMF for 4-6 weeks, the taking of this film should be

delayed until its release.

A pre-debond lateral cephalogram is conditional upon the post-surgical orthodontic

phase exceeding 6 months. This view will record the final post-op position of the jaws at

the completion of post-surgical orthodontics. For patients with shorter periods (<6

months) of post-surgical orthodontics, the ‘1-3 week post-op’ cephalogram should

suffice.

At 1-year post-surgery, a significant number of patients may have only recently

completed their post-surgical orthodontic treatment.

2-years post-orthodontic debond i.e. a minimum of 1 year out of retention, to assess

the final outcome and any relapse associated with surgical orthodontics.

2. OPT

Pre-orthodontic OPG is essential for treatment planning


At the end of the pre-surgical orthodontic phase, there is no need for an OPT if 8s

previously extracted as a result of the pre-treatment OPT.

If 8s haven’t been extracted and are to be removed at the time of surgery, then obtain new

OPT.

The immediate post-op OPT is the responsibility of the surgeon.

3. Study Models

Pre-orthodontic

The pre-surgical planning models are working models. It is not necessary to keep

these “mock-surgery” models long-term.

Post-surgical

4. Clinical Measurements

It should be written record.

5. Altered Sensation

A baseline recording of any altered facial/intra-oral sensation present prior to starting

treatment is good practice.

A simple recording can be indicated on the proforma with further details and drawing

(if applicable) made in the patient’s clinical notes. Subjective testing is sufficient with an

additional note made as to whether the altered sensation is of concern to the patient.

The validated methods to assess the altered sensation was published in 1998 by

Ylikontiola:

A. Light touch (LT)

B. Two-point discrimination (2-P)

C. Tactile discrimination

D. Thermal stimuli (TH)

E. Vitality testing of the mandibular teeth


6. Patient Questionnaires

Psychological-based questionnaire may also be available.

Clinical examination

Patient Evaluation involves:


i) Clinical examination. EOE and IOE

Extraoral examination includes

CFA read CFA notes by Almuzian

TMJ: Although there is no evidence of malocclusion or jaw deformity causing

temporomandibular joint symptoms, it is important to record any abnormalities present in

patients considering surgery. The examination of the joint should include observation of

the path of opening and closure of the mandible, noting any clicking sounds whilst

palpating the joints.

Intraoral Examination

1. Teeth present, unerupted, impacted, carious, over erupted or periodontally involved.

2. Dental and base relationships

3. Dental centre line.

4. Crossbite & associated displacement it is also important to note whether the segments

have attempted to compensate for the discrepancy by tipping of the dentition

5. Overbite

6. Overjet from the most prominent incisor should also be recorded.

7. Arch form and the coordination of upper and lower arches.

8. The upper and lower incisor inclinations and in particular, compensatory changes due

to the jaw disproportion, e.g. retroclined lower incisors and proclined upper incisors in a

prognathous mandible.

9. Crowding or spacing and TSD.


10. Tilting and rotation.

11. COS

12. Occlusal plane canting.

13. Tongue size and mobility, and the speech pattern

14. Enlarged tonsils may jeopardise the patency of the airway. Adenoids are rarely a

problem as they have usually regressed in size during early adolescence. However,

remember that the micrognathic mandible will create an intubation problem for the

anaesthetist

15. Cleft cases require careful analysis of the cleft site and bony defects that will

require grafting. Velopharyngeal competence should be examined by endoscopy and

speech recorded by a speech therapist.

ii) Radiographic examination

OPT

Used to diagnose:

The shape and relative size of each half of the mandible, including the condyles, in

two dimensions.

The presence of any pathological condition such as impacted unerupted teeth, caries,

periodontal disease, apical granulomas or cysts.

The trabeculation pattern of the bone, especially at the lingula, which when visible is

an indication of adequate thickness of the ascending ramus and ease with which the

ramus can be split.


For symmetry analysis, tracing of the normal side of the radiograph has been

superimposed on the abnormal side using the occlusal plane as a guide. The

discrepancy of the mandibular borders can be seen readily

Lateral Cephalometric

To provide precise details of the relationships of the parts of the dentofacial complex

as part of the diagnosis.

To plan tooth angulation movements and osteotomy cuts and movements prior to

treatment commencement.

Analysis of soft tissue and airway spaces

To provide baseline data against which later treatment response can be measured

The tracing of lateral ceph

The soft tissue profile including glabella, nasion, nasal tip, upper lip, lower lip and the

soft tissue chin.

The inner outline of the sella turcica, the anterior aspect of the nasal bones together

with the frontonasal suture and the outline of the lower bony margin of the orbit.

The maxillary outline, upper incisors and upper first molar.

The mandibular outline with the mandibular incisors and first molar and articulare.

In general, where bilateral landmarks present two images, the average of the two

should be drawn. The exceptions to this are those cases where there is an obvious

asymmetry of the mandible, which has resulted in two distinct lower borders to the

mandible. From the point of view of measurement, it is normal practice to take the lower

border which conforms to the normal side of the face, as assessed clinically.


The total anterior face height (TAFH) is the sum of the upper anterior face height

(UAFH), measured from nasion to the maxillary plane, and the lower anterior face height

(LAFH), maxillary plane to menton. The lower anterior face height is usually 55+2% of

the total anterior face height. Posterior face height is similarly measured from sella to

gonion using the maxillary plane to divide the upper posterior face height (UPFH) from

the lower posterior face height (LPFH). The lower posterior face height being

approximately 43 +2% of the total posterior face height


The angle of the maxillary to the mandibular plane (MxP/MP) is normally 27+4. This

angle is important because as with the posterior face height measurement, it reflects the

surgically important pterygomasseteric sling length (muscle, fascia and ligaments). For

instance, a patient with a high angle, i.e. greater than 35, tends to have a relatively short

posterior face height and therefore posterior musculo-ligamentous height. Any attempt to

stretch this posterior connective tissue by rotating the anterior body of the mandible

upwards, in an anticlockwise direction, around a fulcrum produced by the posterior molar

occlusion, is doomed to failure and will lead to early surgical relapse.

If the SN/MxP value is outside this range then Eastman correction cannot be applied

and alternate analyses of the anteroposterior skeletal pattern should be employed like

Wits or McNamara analysis.

Posterior-anterior radiograph

A poster anterior view of the skull helps to reveal facial bone asymmetry.

Long cone periapical films are essential for assessing the space between teeth when

segmental surgery is required.

A maxillary occlusal radiograph defines the bone defect in cleft cases.

Major deformity is best visualised with a 3-dimensional CT scan.

Chest radiograph: If the patient elects to have surgery, a preoperative chest radiograph is

required by some surgeons but is only justified where a costschondral graft is to be

harvested.

iii)Analysis of study models


iv)Psychological examination where appropriate.

Special investigations and assessment

Surgery prediction methods

1. Manual Cephalometric Prediction

A. Overlay Method Tracing

B. Template Method

2. Computer Prediction

E.g. CASSOS

3. Cast Prediction (Model Surgery)

Soft tissue prediction

Upton et al (1997) found that chin; upper lip and lower lip are predictable in 80%, 80%

and 50% respectively. The soft tissue changes depend on:

Age of patient: It is well established that with ageing the tissues become thinner and there

is a loss of muscle tone

Soft tissue composition and tone

Soft tissue thickness

Anatomical variations in the position of muscular attachments to skeletal structures. The

soft tissue responses at sites of muscular attachment are probably greater than at sites of

non-attachment.

Type of surgery

Size of surgery

Presence of dead space between ST and teeth


Racial and individual variations

Soft tissue changes surgery

1. The Le Fort I osteotomy

A. Maxillary advancement:

In almost all cases, a Le Fort I osteotomy results in widening of the alar bases by

approximately 9%. The significant factor contributing to these changes is the soft tissue

dissection rather than the skeletal movements themselves. Periosteal elevation will sever

important muscular attachments (zygomaticus major, levator labii superioris, levator labii

superioris alaeque nasi and nasalis) leading to muscular retraction, alar flaring and

shortening, and flattening and thinning of the upper lip.

Solution: The alar cinch suture, first described by Millard (1980), has been proposed as a

method to control alar flaring at the time of surgery, however, some controversy remains

as to the effectiveness of this procedure (Howley, 2011). There is some evidence to

suggest that an extraoral alar base cinch suture is more effective in maintaining alar base

width, at least in the short-term (<9 months after surgery), compared to the classically

described intraoral nasal suture (Ritto 2011).

upper lip (stomion superius) move by a ratio of 60%. This suggests that there is a vertical

and a horizontal gradient in the movement of the upper lip with the biggest changes

occurring at subnasale, which is a major area of muscle attachment.

Elevation and advancement of nasal tip 30%. In patients with an already upwardly

inclined nasal columella, elevation of the nasal tip can result in an increase in nostril

exposure, which may be detrimental to facial aesthetics. If the nasal dorsum is convex in

shape, nasal tip elevation can lead to accentuation of this convexity. Conversely, if there


is a nasal dorsal hump before surgery, elevation of the nasal tip may improve the nasal

appearance.

Solution: There is no evidence at present that a subspinal osteotomy is superior to a

conventional Le Fort I osteotomy in minimising changes at the nasal tip (Mommaerts,

2000).

Paranasal area move by a ratio of 70%

B. Maxillary impaction:

During maxillary impaction, as a more anterior portion of the maxillary incisor crown

comes to lie against the upper lip with impaction, the degree to which flattening of the

upper lip occurs will depend on the pretreatment inclination of the maxillary incisors.

Where they are proclined, the lip support may increase and when they are more average

in inclination the increase in support may be minimal.

Another effect of maxillary impaction is on the mandible. Maxillary impaction will also

result in anticlockwise (or forward) autorotation of the mandible, which will reduce the

lower anterior facial height and move the chin point further forward. This not only

increases the prominence of the chin point, relative to the forehead, but also increases the

prominence relative to the lower lip. This occurs because the lower lip is positioned

closer to the centre of rotation of the mandible and moves forward less than pogonion.

C. Maxillary set down:

Inferior maxillary repositioning can also help to reduce the prominence of the chin point

by causing clockwise (or backward) autorotation of the mandible.

Inferior maxillary movement may lead to drooping of the nasal tip, alar base and

columella. Care has to be taken that drooping of the nasal tip does not lead to a ‘parrot

beak’ deformity.


During maxillary setdown, the degree to which flattening of the upper lip occurs will

depend on the pretreatment inclination of the maxillary incisors.

D. Maxillary set back:

The effects of a set-back may include a reduction of nasal tip and upper lip support.

This may lead to a reduction of the supratip depression

An increase in the nasolabial angle.

There may be widening of the alar bases due to soft tissue dissection.

2. The BSSO osteotomy

A. BSSO advancement:

With mandibular advancement alone, one can expect a downward and forward

repositioning of soft tissue pogonion with a resultant reduction in facial convexity,

increase in the lower anterior facial height and increase in throat length. The increase in

lower anterior facial height will be influenced by the maxillary occlusal plane inclination,

with a steeper plane resulting in a greater increase in lower facial height.

There may also be an uncurling effect on the lower lip, particularly if the preoperative

lower facial height was reduced.

Although mandibular advancement has no effect on absolute nasal dimensions, setting

forward the chin point may reduce the relative prominence of the nose in comparison to

the forehead and chin point.


B. BSSO setback:

The upper lip may move forwards slightly in a number of cases, possibly because it is not

trapped by the lower lip following mandibular set-back.

Again, the changes at soft tissue pogonion may be more predictable as there is close

attachment of the musculature onto this region.

With mandibular set-back, one may also expect a reduction in facial concavity, a

reduction in submental length, increase in submental soft tissue sag,

an increase of the lower lip-chin-submental plane angle. Submental-cervical surgical

procedures may be required as adjunctive procedures. For example, submental

liposuction may be used to attempt to reduce these negative changes. However, there are

no clinical trials evaluating the effectiveness of this procedure.

Although mandibular set-back has no effect on absolute nasal dimensions, setting back

the chin point may increase the relative prominence of the nose in comparison to the

forehead and chin point.

3. Genioplasty

With advancement genioplasty the reported ratio of hard to soft tissue changes range

from 1:0.6 to 1:1.

An increase in the submental length,

A reduction in submental soft tissue sag,

a decrease in the lower lip-chin-submental plane angle,

deepening of the labiomental fold,


a reduction in facial convexity

a reduction in relative nasal prominence.

Because genioplasty involves dissection of the mentalis muscle, which is important in

elevating the lower lip, there may be an increase in lower incisor exposure following

surgery.

The opposite changes may be expected with set-back genioplasty and a recent study

suggested a soft tissue:hard tissue movement ratio of 1:1 at menton, 0.7:1 at pogonion

and 0.9:1 at B-point. Effects also may include a decrease in the submental length, a

possible increase in submental soft tissue sag, an increase in the lower lip-chin-submental

plane angle, a reduction of the mentolabial fold, an increase in soft tissue thickness, an

increase in facial convexity and a relative increase in perceived nasal prominence.

Error in perdition

1. Errors in carrying out ‘’surgically’’ the planned movements i.e. our inability to move

the teeth and bones to the exactly intended positions. Overall, 80% of the results fell

within 2 mm of the prediction and 43% within 1 mm.

2. Errors in the equipment, materials and software used in the prediction process. Again,

there are again two major sources of error:

3. The usual digitising errors e.g. point identification, posing errors etc. Cunningham

2004 compared OPAL and hand prediction and found that hand type is better in bimax

and similar in mand. surgery alone. The main problem of OPAL is in the region of lip

(Eckhardt, 2004 #41). Smith and Proffit 2004 found dentofacial planner the best as

computer stimulation

4. Prediction of the hard: soft tissue ratio for a given hard tissue movement


What are the risks of showing computer simulations to patients? Bell 1997

1. Better method of informed consent to treatment

2. Reduce the anxiety about the surgical experience

3. No significant difference in the level of satisfaction

4. Increase the concern about the possibility of surgical problems

Pre-surgical orthodontics

Appliance

There is limited use of ceramic brackets in orthognathic cases due to their potential for

fracture.

A 022” slot should be used to allow the use of full thick wires.

A second, or auxiliary, archwire tube can be incorporated into a molar bond or band.

This is useful in cases requiring segmental surgery, if an auxiliary wire needs to be

constructed for placement into the auxiliary tubes to stabilize the segments immediately

after segmental repositioning.

If the mesiopalatal aspect of the maxillary canine teeth is slightly prominent, it may

prevent intercuspation of the anterior dentition, as in this postoperative Class III patient.

This may be prevented by bonding the maxillary canine bracket 1∕2 to 3∕4 of a millimetre

mesial to the long axis of the maxillary canine in orthognathic patients with potentially

reduced maxillary intercanine width. The slight mesio-labial rotation of the canine crown

aids interdigitation.

It is worthwhile considering the variations in bracket tip and torque required in

specific cases. In an ideal occlusion, the crown of the lower incisor lies labial to the apex

for ideal tooth inclination.


A. In Class II cases where proclined lower incisor require decompensation, the use of

MBT brackets with the 6 degree of additional lingual crown torque can aid the

mechanics.

B. Conversely, Super-torque TM brackets, with additional palatal root torque to the upper

incisors, can be useful in correcting severely retroclined incisors in Class II division 2

cases.

C. In class III the use of low torqued upper incisors or inverted torqued LLB.

Mesio-distal tooth angulation (tip) becomes important when considering the

preparation of a case for segmental surgery as it is important to facilitate the surgery (see

below) by ensuring the roots adjacent to the osteotomy site are either parallel or slightly

divergent. Where the osteotomy cuts are to be made distal to the canines, the use of the

canine bracket of the opposite side ensures that the tip incorporated into the bracket keeps

the apices forward and out of the way of the surgical cuts.

Segmental surgery requires the added facility of a double tube on the mandibular

molars and/or a triple.

The use of TPA to control arch width if segmental levelling is used in AOB case, since

intrusion of incisors can cause buccal flaring of the posterior teeth.

TAD can be used for better decompensation

Incorporation of second permanent molars for all orthodontic cases should be at least

considered if not always undertaken. Inclusion of lower second permanent molars in

surgical cases should be undertaken to avoid premature contacts at operation and

problems of arch coordination during the post operative orthodontic phase.

Inclusion of upper second permanent molars is not always indicated particularly if by

levelling the teeth, the teeth are extruded. The overwhelming indication for incorporation


of upper 7s is where the teeth are flared buccally and the palatal cusps are causing

opening of the bite. In such cases the 7s should be incorporated and buccal root torque

applied to intrude the palatal cusp.

The role of orthodontic component of orthognathic treatment

Pre-surgical orthodontic treatment takes an approximate duration of 12-24 months

(Luther et al., 2003) while the tost-surgical orthodontics with an approximate duration of

5-11 months (Luther et al., 2007). Both aim to:

1. Relieve crowding

2. Alignment

3. Complete or partial levelling of the curve of Spee

4. Space closure or sometimes re-localisation prior to restorative procedures

5. Correction of dental centreline discrepancy (within each arch but not necessarily

relative to each other)

6. Transverse arch coordination for post-surgical occlusion (Q helix, RME, SARPE, or

Segmental Le Fort osteotomy)

7. Dentoalveolar decompensation of incisors. Decompensation helps in allowing

maximum jaw movement during surgery which enables the achievements of optimal

facial aesthetic.

8. Provide enough room for segmental osteotomies

9. The orthodontic appliance serves to provide the best means of intraoperative

intermaxillary fixation & to provide for the attachment of post-operative intermaxillary

elastics


10. Creation of optimal buccal segment inclinations to ensure good stability and

function of the final occlusion and as much as possible that all teeth have an opposing

tooth contact at the end of treatment

Levelling of the curves of Spee in the mandible

The decision as to whether to fully level the arches is very much dependent on the

patient's facial height, chin prominence and the upper lip/incisor relationship.

1. If the goal is to maintain face height when the mandible is advanced, pre-surgical

full levelling is required. Levelling the Curve of Spee without space will procline the

lower incisors, and reduce the potential for mandibular advancement. If the intention is to

maintain anteroposterior arch length, then premolar extractions will be required,

especially if there is any crowding present

2. If the goal is to decrease face height when the mandible is advanced,

pre-surgical incisor intrusion by orthodontic applianceis required;

If intrusion is difficult orthodontically, a segmented arch levelling is indicated in the

pre-surgical orthodontics and addressed finally by subapical osteotomies.

Other prefer to deal with levelling similar to average face height then reduced the

skeletal problem surgically as bi-maxillary approach.

3. if the goal is to increase face height , which often is the case in mandibular deficiency

patients, pre-surgical intrusion of the lower incisors would be a serious error and

maintaining or leaving a curve of Spee is indicated.

Maintaining the curve of Spee in low angle cases

1. Prior to surgery, the teeth are aligned and the anteroposterior position of the incisors is

established, but a curve of Spee is left in all the archwires, including the surgical


stabilizing wire. This means the surgical splint will be thicker in the premolar region than

anteriorly or posteriorly.

2. At surgery, normal overjet and overbite are created, and the space between the

premolar teeth is corrected post-surgically by extruding these teeth with flat archwires.

(three point landing)

3. This occurs rapidly, typically within the first 8 weeks after orthodontic treatment

resumes, because there are no occlusal contacts to oppose the tooth movement and due to

postsurgical increase in the metabolic changes (Regional alveolar bone remodelling).

4. The alternatives to use an auxiliary wire to assist in pre-surgical levelling. An

auxiliary levelling wire 17*25 SS passed over the main AW from auxillary molar tube

and it can be tied over a continuous reverse curve base archwire to increase its action.

5. In cases with a severe lateral open bites which are too large to close by orthodontic

extrusion of the premolars and canines. Many operators consider 2 mm of extrusion from

each arch as the absolute maximum that can be achieved and remain stable without

rebound. Beyond this, levelling should be achieved through surgery, usually through a

set-down of the lower labial segment with an anterior mandibuloplasty. Where there is a

reverse Curve of Spee in the upper arch, as in some Class II division 2 cases, it may be

necessary to undertake segmental surgery to both the upper and lower labial segments.

Advantages of partial levelling

1. The absence of premolar contact postoperatively speeds levelling of the occlusal plane

2. The posterior rotation of the mandible at surgery may lead to an overall increase in

face height in appropriate cases

Disadvantages of partial levelling

1. Patients prefer a shorter postoperative treatment period.


2. The extrusion of the posterior teeth with preoperative levelling is likely to be very

similar to the postoperative extrusion, so the face is likely to finish at a very similar face

height. Certainly, intrusion of lower incisors is not beneficial in low face height cases, but

studies suggest that such intrusion is very modest with most mechanics used to level the

occlusal plane and may not be significantly different in the preoperative or postoperative

situations.

Levelling of the curves of Spee in the maxilla

It depends on

Aetiology of AOB

Facial height

Amount of autorotation required

Incisor show

Surgical technique used

Consideration for stability

The steepness of the COS

1. In a patient with open bite, severe vertical discrepancies within the maxillary arch are

an indication for multiple segment surgery. When this is planned, the upper arch should

not be levelled conventionally.

2. The presurgical orthodontics should accentuate the open bite through intrusion of the

labial segments and extrusion of the buccal segments. In this way maximal surgical

correction can be achieved and any postsurgical incisor change will ensure closure of the

anterior open bite


3. Leveling should be done only within each segment, and the segments are levelled at

surgery.

4. This can be achieved by three segmental archwires, two running in the buccal

segments from premolar to molar on each side together with a third segment for the

canine and incisors. This approach tends to produce a lack of control of the tooth

positions and therefore a continuous arch is preferred, from molar to molar but with an

anterior step for the canines and incisors.

5. In the latter case, the surgeon will cut the archwire across the osteotomy site at the

time of surgery. Although the segments are immobilised using rigid internal fixation, it is

essential to provide additional fixation at the occlusal level. This can be done with

A prefabricated continuous archwire bent to the planned postoperative segment’s

position.

However, insertion of this wire intra-operatively can be extremely time-consuming. It

is preferable to use a rigid prefabricated horseshoe shaped 1.0 mm steel supplemental

arch wire, engaged passively into double or triple tubes on the molars and secured by

ligatures to the three archwire segments. Ultimately, the sectional arches can be replaced

with a continuous archwire once the patient has recovered.

Also wafer splint can help in this case

6. If a one-piece osteotomy is planned but extrusion of anterior teeth before surgery

planned to be avoided then TAD can be used to vertically stabilize the anterior segments

or swip in the upper archwire can be placed or the upper incisor bracket can be bonded

more incisally to build some stability against relapse. This type of vertical

decompensation allows for the open bite correction to be primarily delivered through the

surgical procedure, and avoids or at least limits the orthodontic extrusion of the anterior

teeth, which is accepted as being a relatively unstable orthodontic tooth movement.


7. As a role of thumb, for every 1.5 mm of AOB, approximately 1 mm of posterior

impaction will be required.1 mm posterior impaction leads to approximately 1.5◦ of

maxillary incisor retroclination

8. Differential posterior impaction of the maxilla following a Le Fort I osteotomy, which

elevates the posterior maxilla relative to the anterior maxilla and thereby increases the

inclination of the maxillary occlusal plane, will tend to improve the smile curvature

(smile arc) relationship

Dentoalveolar decompensation of incisors

The extraction and mechanics for decompensation is opposite to conventional orthodontic

camouflage. But all should be done with minimum dental health side effect. Presurgical

preparation (decompensation) objectives is to corrects the axial inclinations to:

Maximise jaw movement

For best dental aesthetic


For better function

For stability point of view

To compensate for future relapse

Periodontal health

In skeletal Class III cases,

Lower arch

A. Extraction or non-extraction

It depends on:

Degree of skeletal movement required as well as the target OJ

Curve of Spee

LMA. It is better to avoid extraction in obtuse LMA

Degree of the existing compensation

Thickness of labial alveolar plate, so care to avoid destroying the periodontal

attachment, producing a dehiscence of the gingival margin. Sometimes, periodontal

grafting should be considered.

Degree of crowding. Severely crowded cases may need extractions to provide the

space for arch alignment. The extractions of choice are the lower second premolars,

assuming all teeth to be of good prognosis.


B. Appliance

Use +ve torque LLS as well as increased tip incorporated into the canine bracket.

Invert the lower incisor bracket to get positive labial crown torque

“Laceback” avoided in lower but not upper.

Upper arch

A. Extraction or non-extraction

Degree of skeletal movement required as well as the target OJ

Curve of Spee

Degree of the existing compensation

Thickness of labial alveolar plate, so care to avoid destroying the periodontal

attachment, producing a dehiscence of the gingival margin.

Degree of crowding. The upper incisors generally need to be retracted with upper first

premolars removal. In very mildly crowded cases, some would prefer to move the upper

arch distally using anchorage-reinforcing devices on non-extraction base.

Differential impaction with rotation of maxillary occlusal plane.

B. Appliance

1. In maxillary brackets, laceback ligatures should be employed and the canine brackets

are swapped.


2. Low torque prescription in the maxillary incisor brackets unless the posterior maxilla

is impacted posteriorly by a greater amount than the anterior segment, then the

presurgical preparation may intentionally leave the upper incisors slightly proclined.

3. Class 2 traction is frequently required in these class 3 cases and vice versa.

4. Additional active labial crown torque should on occasion be employed to assist soft

tissue recoil which means that the upper lip will apply a palatally force after maxillary

advancement which might cause some relapse.

In skeletal Class II cases

Exactly opposite to the above.

Transverse arch co-ordination

Methods of maxillary arch expansion relate to four factors:

1. The amount of discrepancy

2. The inclination of the buccal segments

3. Bone thickness buccally

4. The proposed surgical procedure. (i.e. single jaw or segmental)

Technique of arch coordination

1. Accept a bilateral posterior crossbite in some instances but may complicate the

achievement of a satisfactorily stable occlusion in the post-operative period

2. Widening or narrowing of the full-sized archwires with buccal or lingual root torque

respectively (dental expansion or constriction)


3. A quadhelix tends to tip teeth and the hanging down of the palatal cusps interferes

with a good stable intercuspal and functional occlusion.

4. RME (e.g.: a rapid expansion splint) are less appropriate in an adult with a closed mid-

palatal suture.

5. Surgically –Assisted Rapid Maxillary Expansion (SARPE): Advantages and

disadvantages:

No periodontal hazard like Lefort I two piece maxilla to expand the UA.

Simpler orthodontic preparation - no need to create spaces for segmental osteotomy

cuts

Less extractions required

Asymmetric expansion possible ( unilateral lateral corticotomy)

Better at canine expansion than molar expansion

6. Segmental Le Fort osteotomy

Segmental-midline- Le Fort surgery (Bailey et al 1997) must be very carefully carried

out to avoid periodontal damage between the upper central incisors and some clinicians

advocate the creation of a median diastema as part of the orthodontic preparation if the

constriction is required.

The surgery must be mimicked on models and an orthodontic archwire and wafers

made to the planned new archform to be created during the surgery.

The new archwire should ideally be inserted during the operation and the chance of

the wafers not fitting well is increased.


Advantages and disadvantages

No additional operation or two phase operation like SARPE

Better for molar expansion

Better stability

More complicated and lengthy Le Fort procedure

More complicated orthodontics to create and then resolve spaces for interdental cuts

Pd damage.

Monitoring Arch Coordination

1. For Class II problems, testing of arch co-ordination in the transverse dimension can be

achieved by simple forward posturing of the mandible.

2. In Class III corrections the use of

An acrylic template of the occlusal surfaces of the lower arch

is invaluable. The template can be prepared by taking an alginate

impression of the aligned lower arch and pouring cold cure

acrylic resin into the occlusal portion of the impression. At

successive visits, the template of the lower arch can then be

occluded with the upper arch to check compatibility and avoid

the need for repeated study models.

Another method is by using the lower AW as a guide which should fit passively along

the central fossae of upper teeth and touch the cingulum of upper incisors.

Using acrylic model of lower dentition attached to holding wire and compared directly

to upper arch

Using study model


Using digital study model

The Definitive Treatment Plan

A. The key to successful surgery is to place the maxilla and the decompensated maxillary

incisors in the optimum anteroposterior, transverse and vertical position in relation to the

upper lip and face (PIP). The mandible is then placed in a Class I incisor relationship to

the maxilla.

B. The movements of the maxilla based on the clinical prediction of the incisor position,

can then be repeated on a digital image or tracing of the patient's lateral cephalometric

radiograph.

C. The clinician can use software package or hand tracing. When planning using hand

tracing it is important to trace all the teeth in order to avoid missing potential premature

contacts

The maxilla

1. The incisor exposure with the lips parted at rest — will decide the vertical movement

of the maxilla. Aesthetic exposure may vary from 1 to 4 mm. This is inversely

proportional to the upper lip length which ranges from 18-24 mms.

2. Excessive or unaesthetic incisor exposure is corrected with appropriate maxillary

impaction. But where the upper lip is unduly short, the patient can show a greater amount

of incisor.

3. Rarely the patient has marked dento-alveolar hypoplasia and shows little or no incisor

with a normal lip length. This is corrected with an inferior movement of the maxilla.

4. Horizontally, the maxilla advance until best stable and biologically acceptable position

achieved in relation to zero meridian


5. Horizontal movement similar to the vertical maxillary movements will affect the

incisor exposure. Advancing the maxilla will lead to greater incisor exposure which will

need to be adjusted for when considering the vertical move. V-Y closure of the lip can be

used to compensate for the increased incisor show after maxillary advancement.

6. Coronal occlusal cants and midline rotations must also be corrected

7. Moving the maxilla will also affect the nose. Vertical impaction widens the alar base

and forward movements will elevate the nasal tip. Depending upon the initial appearance

these changes may or not be desirable. If not, then a record should be made to provide a

“cinch suture” across the lateral alar cartilages or to reduce the anterior nasal spine at the

time of surgery

NB:

The inherent inaccuracy of the planning and surgical technique and the eye's inability

to perceive small anatomical changes, determine that units of horizontal advancement

should be no less than 3 mm. This also facilitates planning as a 3 mm minor

advancement; a 6 mm intermediate; and a 9 mm major move. Cleft cases usually require

9 mm or more.

Similarly vertical moves of 2 mm for minor; 4 mm intermediate and 6 mm for major

impactions are appropriate for all cases. These three categories also simplify the decision

making process.

The mandible

1. Having planned where the maxilla is to be placed, the final step is to place the

mandible in a Class I incisor relationship. This is built into the final wafer.


2. If the definitive occlusion is not immediately possible because of the need for further

orthodontics or restorative treatment, the wafer maintains the jaw relationship until

orthodontics or restorative treatment can be commenced.

3. The mandible will require

Autorotation: any changes in the vertical and horizontal position of the maxilla will

necessitate a change in the vertical and AP position of the mandible. This is mediated

naturally through neuromuscular feedback mechanisms and the mandibular elevator

muscles.

Antero-posterior: forward movement of the mandible to establish a Class I incisor

relationship in Class II cases, will also increase lower face height in deep overbite

specially when advancing the mandible without levelling the curve of Spee. The vertical

facial height will increase and the everted lip will unroll and upright. If this change is

desirable, the consequent lateral open bites need to be closed with postsurgical

orthodontics to a stable position. If too severe for orthodontic closure, then surgery must

incorporate a levelling of the occlusal plane with an anterior subapical osteotomy. On the

other hand, mandibular setbacks will evert the lip. Occasionally this may correct the

occlusion but reduce the chin prominence which will require a paradoxical advancement.

Vertical, no anti-clockwise stretching allowed because of relapse tendency. The only

vertical movement is autorotation. Some evidences showed that the tolerable degree of

anti-clockwise stretching is between 5-8 degree.

Rotational or rarely transverse movements. These are required in asymmetry cases,

for example hemimandibular elongation where the need is arch coordination especially

with an adequate maxillary intercanine width.

Revision of the plan after autorotation


1. Assessment of the lower incisor position of the autorotated mandible is also important

in determining if further adjustment of the maxillary position is required in order to

establish a positive overbite.

2. With an anterior open bite autorotation leads to initial buccal segment contact. Closure

of the residual anterior open bite by (anticlockwise) rotation of the mandible around this

posterior pivot will lead to an elongation of the pterygo-masseteric sling and relapse. In

such cases it is necessary to impact the posterior part of the maxilla differentially to that

of the anterior maxilla. The extent of the differential impaction can be ascertained from

the tracing.

3. With impactions for vertical maxillary excess, any minor incisor discrepancy on

simple autorotation can be overcome by forward or backward adjusted movement of the

maxilla. A significant discrepancy will require a bimaxillary procedure to ensure the

incisor Class I relationship without compromising the upper lip incisor relationship.

Chin Position

Both anteroposterior and vertical movements of the mandible will affect the position of

the chin. It is important that the chin be carefully assessed to avoid further surgery.

The immediate pre-surgical phase of treatment

1) Final records: Immediately prior to surgery records should be taken so that final

surgical plan can be confirmed. This include study models, photographs and lateral

cephalogram with OPT or even CBCT

2) Model surgery: The models should be mounted on a semi adjustable articulator. So the

precise surgical movement can be performed on the models. Acrylic intermediate and or

final interocclusal wafers are also constructed from the models


3) Final AW: Final rigid wire with hook is important to stabilize the wafer and to allow

the use of elastic later on. There are a number of different types of hooks:

Crimpable (Crimpable hooks can be placed and secured with a pair of crimping pliers

in situ. The advantage is that the arch wires need not be removed and accurate placement

can be made with ease. The problems that may occur include( Unappreciated arch wire

distortion leading to unwanted tooth movement; Inadequate crimping leading to loose

hooks; Bracket debonding). Crimping hooks with arch wires out of the mouth is a more

reliable method, but placement is more difficult and removal of the wires is required,

extending the length of the appointment

Slide-on;

Soldered hooks (Soldered hooks have the advantage of avoiding loose hooks, but

soldering is technically challenging both in terms of placement and annealing the arch

wires)

Hooks attached to brackets, but can make oral hygiene difficult and subsequent tooth

decalcification a real risk.

4) Patient preparation:

Patient consent

Instruction about the post-surgical complication

postoperative regimens for feeding and oral hygiene

5) Preoperative Investigations like full blood count

6) Blood transfusion: With the increased concern about cross-infection, autologous blood

is now being used in some centres for elective surgery.


Model surgery and wafer splint for orthognathic patient

Cast Prediction (Model Surgery)

Model surgery is the dental cast version of cephalometric prediction of surgical

results.

It can be done before the orthodontic preparation by wax setting of crowded teeth

might needed.

The primary goal of model surgery is to functionally and spatially simulate the

patient's jaws and dental structures as accurately as possible to allow accurate simulation

of the intended surgery.

The secondary goal is to construct surgical wafer splint: the wafer is a rigid

interocclusal custommade splints used in orthognathic surgery to guide intraoperative

repositioning of the jaws, consisting of an acrylic resin prosthesis wired to the fixed

orthodontic appliance/teeth in the maxilla (or mandible) and joined intraoperatively with

stainless steel ligatures or elastics to keep the segments immovable while repositioning

the jaws

Procedure of cast prediction (Model Surgery)

1. The selection of articulator is the first step in preparation for effective model surgery.

it includes:

a. Plain line or simple hinge articulator used in case of:

Mandibular as a single jaw procedure.

Maxillary advancement with no height change of the Maxilla i.e.: no impaction / no

down graft.

Segmental surgery with no height change.

b. Semi-adjustable articulator: an articulator that allows adjustments that reproduce

mandibular movements in the sagittal plane only.


Maxillary osteotomies with height changes i.e.: impaction or downgraft.

Bi-Maxillary procedures.

Segmental or multi-part maxillary osteotomies.

Cases of facial asymmetry.

c. adjustable articulator: an articulator which may be adjusted to accommodate the

various positions and movements of the mandible relative to the maxilla.

d. Fully adjustable articulator – allows replication of three-dimensional movement of

recorded mandibular motion.

Semi-adjustable articulator (Dentatus).

2. Face Bow Selection.

The function of the face bow recording is to mount the maxillary cast on the articulator to

reproduce the anatomical position of the maxilla in its relation to the base of the skull.

There are many types including:


a. The auricular face bow

b. Condylar face bow

c. Condylar face bow with spirit bubble

3. The maxillary dental cast is mounted on a semi adjustable articulator with the aid of a

facebow transfer from the patient.

4. Next, the mandibular dental cast is mounted with the aid of a bite registration taken

with the patient's jaws in the retruded contact position, or centric relation.

5. Several measurements should be done first, this be accomplished by drawing several

vertical reference lines and two horizontal reference lines on. The distance between the

facial surface of the maxillary incisors and the articulator pin is recorded.


6. Model simulation of anticipated surgical movement (that has been determined by

cephalometric prediction tracing and/or clinical data) performed next.

7. The sequences of movements are:

The maxillary cast is repositioned first according to the measurements from the

prediction tracing.

Once the maxillary cast has been fixed in the new position on the articulator,

The first stage or the intermediate occlusal wafer splint is generated

The mandibular cast then is repositioned to oppose the maxillary cast, simulating the

final position of the jaws at surgery. This final position generates the final occlusal wafer

splint for use at surgery and during the period of jaw rehabilitation following surgery.

It is easier for the surgeon to use a second identical set of dental casts mounted in a

hinge-type articulator for the final splint because the occlusal surfaces of the first set of

casts can be damaged in construction of the intermediate occlusal wafer splint.

Then the measurement is compared to what had been planned before.

In order to measure the proposed surgical moves on the models, some form of

measuring instrument is required. Either a model repositioning instrument may be used or

a model measuring block, such as the Erickson Model Platform and Block, see below,

(Great lakes Orthodontics, Tonawanda, New York), may be used to measure the current

position of the maxillary central incisor edges, canine cusp tips, and the mesiobuccal cusp

tips of the maxillary first molars. These three-dimensional measurements may be used to

reproduce the maxillary model’s exact location and to determine the proposed new

position. The distances the maxilla will move in the three planes of space and in relation

to the three axes of rotation will have been determined at the clinical and cephalometric

planning stages.


Technical advises

It is essential to use recent models for wafer fabrication

Impressions must be taken at least two weeks after any final adjustment of the

orthodontic stabilizing arch wire

It is advisable to maintain the archwires in situ when taking the impressions in order to

prevent the possibility of minor unwanted tooth movements during the taking of the

impressions and during the replacement of the archwires.

A wax strip is flattened between the fingers and slid underneath the archwire and

brackets, and moulded in position in order to prevent the impression material flowing

underneath the archwire. However, with the wax in place, the occlusal aspect of the

brackets should be visible, and not covered by the wax


When choosing the size of the impression tray it is essential that all the teeth within

the respective dental arch fit inside the boundary of the tray

It is also important that the alginate material does not lift out of the impression tray.

If there are deep fissures in the occlusal surfaces of the posterior dentition, it is

advisable to smear some alginate along these surfaces with a finger just prior to taking

the impression. This will reduce the chance of air blows in the alginate, which would

otherwise compromise the postoperative position.

Wax bite registration should be very accurate. If there is a posturing during registering

the wax bite and the patient is undergoing BSSO, then there could under correction and

vice versa in Le Fort advancement. If the patient is undergoing a bimax surgery then

maxillary position could be in the wrong place as the intermediate wafer will be incorrect

Casting the dental impressions Due to the possibility of damage to the models, plaster

of Paris is no longer advisable for casting of the impressions. A polyurethane resin (Hit

Model, Euro Resina, Italy) produces a scratch resistant model, and metal retention rings

(Retention Washers, Skillbond Direct Ltd. UK) are placed in the resin as it sets to allow

for the retention of the plaster


Proffit and White advised that the thinnest practical wafers had 1 to 2 mm

If the maxilla must be segmented at surgery, a combined or two-stage splint can be

constructed. This technique involves construction of the final splint first (on a hinge

articulator) followed by fabrication of the combined splint

For mandibular surgery alone, if there is an obvious and well-interdigitating proposed

postoperative dental occlusion, a wafer splint is not absolutely essential. The

osteotomized mandible may be secured intraoperatively into the postoperative position

using the dental occlusion as the guide to the new position. However, most surgeons still

prefer a final splint to be prepared for surgery

The uses of the surgical wafer

1. Translate the planned surgery to the reality in the theatre. An intermediate splint is

used to reposition the maxilla relative to the unmoved mandible, and this splint forms the

prescription for the repositioning of the mobilized maxilla to the unmoved mandible in

the sagittal and transverse planes (the vertical position of the maxilla is decided using

some form of skeletal reference guide intraoperatively). A final splint is used to

reposition the mandible relative to the new maxillary position.


2. Intermediate and final splinting in bimaxillary surgery

3. Splint the segmented arch

4. Maintain the maxillomandibular relationship in overcorrected position if these are

planned. They enable a positive occlusion in an overcorrected position which is not

dictated by the intercuspal position. e.g. class 2 cases can be set up edge-to-edge and

class 3 cases to a slightly increased overjet

5. For postoperative rehabilitation or Post-Operative Proprioceptive Guidance. After

rigid fixation of the mandible, the wafer may be wired to the maxilla, or less frequently to

the mandible, to provide post-operative proprioceptive guidance for up to two weeks.

The wafer will help the patient to occlude into the planned position with or without the

help of elastics by overriding the patient’s pre-operative proprioceptive drive. This also

improves the arch relationship for any final orthodontic refinement of the occlusion.

Materials and Types of Occlusal Wafers for Orthognathic Surgery

1. Self-cured

2. Heat-cured methyl methacrylate

3. Cast in silver or cobalt chromium alloy for difficult cleft palate cases.

4. A palatal wire may be added for reinforcement in case of segemental osteotomies.

Causes of error in model surgery,

1. It is essential that the angle between the occlusal plane and the Frankfort horizontal for

the patient is the same as the angle between the occlusal plane and the upper member of

the articulator on the maxillary model. If this is incorrect, the result of the model surgery

is erroneous.

2. The other source of error is the difference in the patient’s mandibular position when

supine and upright; the mandible tends to be positioned more posteriorly when the patient

is lying down. Therefore, less maxillary advancement would be achieved than predicted

on the articulator and the mandible has been overcorrected (more setback) to compensate


for maxillary under-advancement. Under general anaesthesia, the muscles of mastication

are relaxed and the mandible would not serve as a fixed reference plane for maxillary

surgery. BAMBER et al recommended recording the centric relationship in the supine

conscious position when planning bimaxillary osteotomies.

3. There is the accuracy of mandibular autorotation simulation. There is evidence that

even the initial rotational movement of the condyles in mouth opening involves a small

element of condylar translation as well. That is, the movement is not a simple rotation

around the condylar hinge axis.11 Although this is likely to be a minor issue in

orthognathic surgical planning, nevertheless, it does add an element of inaccuracy in

model surgery on a semi-adjustable articulator.

4. The other possible source of errors in planning orthognathic surgery is the inaccuracy

in registering and transferring the true hinge axis of the condyle to the articulator

specially when the condyle is in different level which may incorporate a pseudo-cant.

5. Wax bite error

6. Impression inaccuracies

7. The last cause of error is the main cause of this inaccuracy is that they are not

designed to record facial asymmetry accurately.

Several factors can increase the accuracy and good fit of wafers

1. Leave heavy wires passive for one visit before taking the impression

2. Either take the impression with rubber compound or if using alginate ensure that it

does not lift from the tray

Choosing a larger tray and therefore thicker sections of alginate

Use a tray adhesive

Block undercut by wax

Remove the impression by pushing on the alginate not by pulling on the tray


3. Insure the facebow is accurately located

4. Construct any intermediate wafer in a different colour acrylic to avoid confusion at

operation

Alternative method of model surgery

1. 3 D model surgery

2. virtual model surgery

3. In facial asymmetry the use of orthognathic articulator is preferable

4. Splint wafer modifications for partially dentate or edentulous patients. In partially

dentate patients missing their posterior dentition, or in the uncommon situation that an

edentulous patient requires orthognathic surgery (e.g. for treatment of sleep apnoea),

modifications to the surgical wafer splints are required. Use of a modified Gunning-type

splint, originally described for use in maxillofacial trauma, is a potential possibility, in

which case the occlusalvertical dimension (OVD) must be determined (Figure 13-18).

The Gunning splint is an eponym for a device fabricated from casts of edentulous

maxillary and mandibular arches to aid in the reduction and fixation of a jaw fracture,

named after the English-born American dentist Thomas Brian Gunning (1813–89).


Problem with snap model

1. Interferences from 2nd molar teeth: Usually arise from absence of bands on lower

second molars and presence of upper 7’s!

2. Incompatible Intercanine: Typically maxillary intercanine width is slightly narrow

compared with mandibular canines therefore casts cannot be positioned without creating

an AOB

3. Lack of space for interdental osteotomy cuts for segmental surgery: need 4-5mm of

separation of roots to cut between with no undue risk

Surgical procedures and treatment possibilities

Envelope of Surgery

Once the amount of anteroposterior movement required for correction exceeds 1cm

consideration should be given to operating on both jaws

Set back of the maxilla is possible by 5-6 mm but very difficult.

Care must be taken not to compromise the blood supply by over stretching the tissues

Maxillary Surgery

A. Total maxillary osteotomy

1- Le Fort I. The surgical cut goes through the wall of the maxillary sinuses, the lateral

nasal walls and the nasal septum at the level just superior to the apices of the maxillary

teeth. Le Fort I is not indicated in maxillary set back because of:

The negative effect on the profile

The anatomical restriction

Telescoping of the maxilla in the sinus.


2- If down grafting of the maxilla is performed, it is better to combine it with mandibular

relieving surgery

3- In Le Fort I, the septum needs to be reduced inferiorly if the maxilla is going to be

impacted. Failure to do this will result in nasal deviation postoperatively. A groove can to

be made for the septum along the palate and into the anterior nasal spine. The septum can

be sutured centrally through a hole in the anterior nasal spine.

4- Bone needs to be removed around the piriform fossa to help avoid nasal widening and

unwanted changes to the nasolabial angle

5- If a maxillary impaction, particularly without advancement, is required, bone may

need to be removed in many areas including the area where the greater palatine vessels

enter the bony channel in the maxilla to avoid the unintentional advancement due to the

wedging effect og the pterygoid plates. A decision must be made either to preserve the

vessels or to deliberately use bipolar diathermy and divide the vessels. Another technique

is to use a small osteotome above the vessels. Bone needs to be removed from wherever

it prematurely touches, thereby preventing the seating of the mobile maxilla.

6- Occasionally the inferior turbinates need to be removed to permit adequate superior

repositioning of the maxilla. These are vascular structures; from a practical aspect the

blood supply comes from the posterior aspect of the turbinates and travels anteriorly.

Therefore haemostasis either with the Colorado needle or bipolar haemostasis is essential

in this region.

7- Nasal changes related to the Le Fort I osteotomy

The advantage of submental intubation is most apparent in assessing the nasal changes at

the time of the Le Fort I osteotomy and adjusting the hard and soft tissues to reduce any

unwanted effects.


Unwanted nasal tip rotation can be controlled by a combination of reduction to the

anterior nasal spine, piriform aperture sculpting (particularly the lateral nasal wall) and

adjustments to the inferior part of the nasal septum

Subspinal osteotomy

8- Widening of the alar base.

Techniques such as piriform aperture widening and cinch suturing can reduce the

unwanted widening.

Traditionally, the suture is secured to the anterior nasal spine. This has the frequently

unwanted effect of elevating the nasal tip, thereby increasing the nasolabial angle.

However, if the technique is adapted to pass the suture directly under the septum rather

than to the anterior nasal spine, it results in narrowing but with fewer adverse effects on

the nasolabial angle

Subspinal osteotomy

9- Increase incisor show can be controlled by combination of

Reducing the alar width (if appropriate),

using the VY-plasty suturing technique. This is a technique where the straight horizontal

incision below the lip is converted to a Y-shape.

10- Le Fort II. It is a pyramidal osteotomy; it differs from Le Fort I that it passes

anteriorly toward the orbit. It is used mainly with CLP.

11- Le Fort III. It is used for the correction of symmetrical mid-face recession affecting

zygomatico-maxillary and orbital regions.

12- Le Fort II modified Kufner technique


The nasal bridge is not involved, but the surgical cuts runs anterior to the lacrimal

apparatus and laterally to the zygoma.

It is indicated when the nasal bridge and projection are both good, but the infra orbital

region and the dentoalveolus are retruded, with mild zygomatic flattening.

13- High level Le Fort II

The cuts along the orbital floor may be extended laterally to include increasing areas of

the inferior orbital rim and malar body, full extension will turn the procedure to sub

cranial Le Fort III.

B. Segmental alveolar maxillary osteotomy

1. Anterior segmental osteotomy. Mobilize the anterior segment of the maxilla and

allows the reposition in an upward, downward and a rotational manner.

2. Posterior segmental osteotomy (The Posterior Dentoalveolar Segmental Osteotomy of

Schuchardt)

3. Anterior and posterior segmental osteotomy.

C. Maxillary osteotomies for transverse problems

1. LeFort I down fracture surgery with parasagittal osteotomies

LeFort I downfracture surgery used for treatment of Maxillary transverse problems. It

consist of parasagittal osteotomies in the

floor of the nose or floor of the sinus that are

connected by a transverse cut anteriorly. A

midline extension runs forward between the

roots of the central incisors.


If constriction is desired, bone is removed at the parasagittal osteotomies according to

presurgical planning.

In expansion, either bone harvested in the downfracture or bank bone is used to fill the

void created by lateral movement of the posterior segments.

2. LeFort I down fracture surgery with midsagittal osteotomies

3. Surgically-assisted palatal expansion, using bone cuts to reduce the resistance without

totally freeing the maxillary segments, followed by rapid expansion of the jackscrew, is

another possible treatment approach for adult patients with skeletal maxillary

constriction.

Soft tissue effects of Le Fort I advancement

1. Nasal tip is advanced by one sixth of the maxillary advancement (Henderson et al

1984).

2. AP advancement of the lip 60-80% and the tip of nose 20%

3. NLA decreased.

4. Upper lip flattens.

5. Vermilion exposure increased.

6. Increase in the width of the alar base

7. Tip of nose move superiorly

8. Lower lip rolled and advanced

In case of maxillary impaction, the following should be noted

It is important to shorten the nasal septum or free its base so that the septum is not

bent when the maxilla is elevated.


The inferior turbinate can be partially resected if needed to allow the intrusion,

although this procedure rarely is necessary.

The overall facial height is shortened as the mandible responds by rotating upward

and forward. Further surgery to correct the anteroposterior position of the mandible may

or may not be necessary after this rotation, depending on functional and esthetic concerns

Excellent stability of the vertical position of the maxilla is observed post-surgically,

but long-term, some continued vertical growth of the maxilla may occur.

In contrast, in case of maxilla moved downward, the following should be noted:

It tends to relapse back up post-surgically, so that 20% or more of the vertical change

often is lost even when rigid fixation is used.

Both the use of more rigid graft materials (like synthetic hydroxylapatite) and

simultaneous osteotomy of the mandibular ramus have been reported to improve the

stability of downward movement of the maxilla, but this remains one of the more

problematic movements

Mandibular Surgery

Bilateral Sagittal Split Osteotomy (BSSO)

Indication

1- Mandibular advancement(less than 10 -12 mm).

2- Mandibular set back (less than 7-8 mm).

3- Correction of asymmetry (Minor).

4- It is not recommended in patients with an anterior open bite without considering a

simultaneous maxillary operation to reduce the posterior facial height.

NB:

Patient should warn of parasthesia with mandibular advancement


About 20% - 25% will have some degree of long term altered sensation

In case of mandibular setback, Airway should be assessed

Vertical Subsegmoid Osteotomy (VSO)

Indication:

1. Large mandibular set back

2. Restricted mouth opening

3. When splat might occurs bec of thin ramus

(Yoshioka 2008) compared intraoral vertical ramus osteotomy (IVRO) versus sagittal

split ramus osteotomy (SSRO) and found similar outcome in relation to condylar position

and stability one year postoperatively.

Advantages

1. Less risk of damage to the ID nerve. Permanent paraesthesia is thought to be

approximately 5% for the VSSO versus 25% for the BSSO

2. This procedure requires less time than the sagittal split osteotomy

Disadvantages

1. Intermaxillary fixation is required because access for rigid fixation is not possible

2. Reduce ramus length and height


Inverted L osteotomy

Indications

1. Big advancement where the mandibular rami are deficient both vertically and

horizontally.

2. Big set back.

3. Big asymmetry.

Body osteotomy

The objective is to remove a pre-planned segment of mandibular body allowing the

anterior segment of the jaw to be set back.


Lower labial segemental osteotomy (Subabical ostectomy)

Indications:

1- An exaggerated curve of Spee.

2- Correction of bimaxillary protrusion.

Anterior mandibuloplasty

It combines lower labial segment surgery with simultaneous genioplasty, all the cuts

being continuous.


Genioplasty in Orthognathic Treatment

A. Reduction genioplasty:

1- Vertical reduction genioplaty.

2- Horizontal reduction genioplasty.

B. Augmentation genioplasty:

1- Vertical augmentation.

2- Horizontal augmentation. (sliding or double sliding genioplasty)

Technique

By free a wedge-shaped portion of the symphysis and inferior border that remains

pedicle on the genioglossus and geniohyoid muscles.

This segment can be advanced to augment chin contour, shifted sideways to correct

asymmetry, or downgrafted to increase lower face height.

By splitting the segment vertically, the distal aspects of the wedge can be flared or

compressed.

If narrowing of the anterior portion is needed, bone is removed in that area.

When reduction is desired in the distance from the incisal edge to the inferior aspect of

the symphysis, a wedge of bone can be removed above the chin


Genioplasty as an adjunct to non-extraction orthodontic treatment

1. Prominence of the lower incisors relative to the chin traditionally has been treated

orthodontically, by retracting the incisors to establish proper tooth-chin balance, But

when the lower incisors are retracted, the upper incisors also must be retracted.

2. For some patients, this creates the risk of an unesthetic flattening of the lips and can

make a large nose appear even more prominent.

3. For such patients, a lower border osteotomy to augment the chin provides an

alternative to premolar extraction and retraction of prominent lower incisors

4. In theory, advancing the chin decreases lip pressure against the lower incisors and

makes them more stable in an advanced position. Although case reports suggest that this

may be correct, it has not been established scientifically

Integration of Orthognathic and Other Surgery

1. Rhinoplasty

It can correct the nasal prominence and elevation of the nasal bridge that often

accompanies severe Class II malocclusion. If the jaw asymmetry exists, there is about a

30% chance that the nose also is affected, so it is important to evaluate the nose carefully

in asymmetry patients.

It is better for the patient to have both procedures done as part of the same operation,


Simultaneous mandibular advancement and rhinoplasty usually can be accomplished,

but it is more difficult to combine maxillary surgery and rhinoplasty, and still more

difficult to combine nasal and two-jaw surgery. A second-stage rhinoplasty, typically

done 12 to 16 weeks after the jaw surgery, often is the best plan for patients with major

asymmetry

Examination of the nose

A detailed examination of the internal and external aspects of the nose is performed.

Anterior rhinoscopy to detail mucosal, caudal septal and turbinate deformities is

supplemented with an endoscopic evaluation of the posterior nasal cavity and middle

meatal areas to exclude infective or obstructive sinonasal disease.

The internal nasal valve area which is bounded by the upper lateral cartilage, inferior

turbinate, nasal septum and nasal floor is

specifically examined and any high septal deformity

noted. This is the narrowest part of the nasal airway

and significant internal nasal valve collapse can be

examined by Cottle's test in which the airway

improves when the cheek adjacent to the mid third

of the nose is pulled laterally.


The importance of the balance of the nose to other aspects of the face is important.

Assessment of this relationship should form the initial part of the external examination

process.

The patient's ethnic characteristics must also be considered. Facial and nasal asymmetries

are documented and detailed to the patient.

2. Tongue Reduction

Indications: The enlarged tongue is an uncommon cause of anterior open bite and

osteotomy failure. If it appears to be large and the incisor teeth are proclined and

separated, surgical reduction is indicated and can be carried out prior to orthodontics or

with segmental osteotomies.

Where there is any doubt, the patient should be informed that it may be necessary

sometime after the dental alignment or osteotomy, and the case is carefully followed up

at 3-monthly intervals to prevent any gross relapse. This will take the form of recurrent

proclination and separation of the incisors. Once this is obvious, reduction should be

carried out and any dental relapse can be corrected orthodontically.

3. Collagen and Botox

Collagen injections treat the same facial wrinkles that BOTOX® Cosmetic does,

including frown lines, crow's feet and forehead creases. Collagen injections can also be

used to compensate for fat loss in facial tissues, lip augmentation, and to fill in acne scars

or dark under eye circles. While bovine collagen injections like Zyderm and Zyplast are

still used today, patients are required to undergo a skin test prior to treatment to ensure

against allergic reactions. By comparison, human collagen injections like CosmoDerm

and CosmoPlast can cost more, but they are proven non-allergenic treatments.

Botox injections don't technically qualify as a dermal filler because their treatments

use the botulinum toxin type A, a neuromuscular blocking toxin, rather than a filler

substance. The botulinum toxin relaxes tense facial muscles so that the appearance of

wrinkles and fine lines is temporarily eliminated. Botox is FDA approved for the


treatment of wrinkles and poses the risk of a few minor side effects like temporary

bruising. Overall, Botox and collagen injections are considered safe procedures for the

majority of patients

Distraction Osteogenesis

Inducing a callus of bone by osteotomy or corticotomy followed by distraction of

proximal and distal ends resulting in increase of bone length .

Following an appropriately designed osteotomy, carefully controlled tensile forces are

gradually applied to the callus increasing the regenerative immature bone laid down

between the cut ends.

Over time, the bone remodels into mature bone and the surrounding soft tissues adapt

to their new content and length.

Indication

1. Correction of sever congenital craniofacial defects

Micrognathia (up to 24mm elongation reported)

Correction of mid face retrusion

Craniofacial abnormalities, e.g. Crouzons; hemifacial microsomia;

2. Maxillary hypoplasias due to previous cleft palate surgery; to allow slow and

gradual soft tissue adaptation to the new bone position.

3. Palatal and mandibular expansion;

4. Dentoalveolar hypoplasia for implant insertion;

5. Tumour/trauma reconstruction;

6. TMJ ankylosis.


Advantages

1. Used at an earlier age

2. Improves soft tissue functional matrix

3. Less relapse

4. Reduces need for bone grafts

5. Some claim that distraction produces less disturbance of speech with reduced

incidence of VPI.

6. Can achieve movement in 3 plane of space

Disadvantages

1. Movement limited by distraction device

2. Infection

3. 2 operations required: one to place, one to remove

4. Damages to

Teeth by screws, pins and bone cuts

Nerves by direct injury and traction injury

Skin scarring by transcutaneous pins if it is used

Tmj

Types of Distractors

1. Internal Distractors

Are partially buried


give excellent control over vectors,

require adequate bone

patient with good manual dexterity to turn the

2. Extra-Oral Distractors

Are easier to activate,

give less control over the vectors of distraction,

do not control the posterior maxilla well,

require a frame that is a disadvantage

Types of Extra-Oral Distractors

LeFort I Distraction

LeFort II Distraction

LeFort III (Kufner) Distraction

Techniques

1. Corticotomy or osteotomy

2. 7 day latency period, until intact vascular supply established

3. Prolonged, progressive and gradual distraction, correct rate and rhythm of distraction

which should be 1mm/day:

below 0.5mm / day-- premature union

above 1.5mm / day- non-union


4. Consolidation period of 8-10 weeks

5. Digital simulated distraction can also be carried out for the more complicated cases

prior to surgery with STL models.

6. The control of the distraction vector of movement can be achieved using three

dimension distractor or with the aid of intermaxillary elastic to counteract any unwanted

movement.

Fixation for orthognathic surgery

Fixation of the jaws following an osteotomy plays a very important role in promoting the

union of the repositioned segments. Any movement of the osteotomised segment can

impair healing, which may result in a fibrous union, non-union or mal-union.

Types of fixation

Fixation methods can be classified as external, internal fixation (rigid or non-rigid

transosseous wire fixation) and supportive IMF.

a. Extra-osseous fixation.

1. Occlusal wafers.

2. Fixed orthodontic appliances with supplementary arch wires and tubes.

3. Cast metal splints. Cast metal splints have become less popular because of the clinical

and laboratory complexity and are usually confined to the unstable components of a cleft

case.

4. Arch bars either prefabricated flexible or cast cobalt chromium. Prefabricated Flexible

(Erich — Dentaurum, Pforzheim, FRG) is made of semi-rigid stainless steel. It can be

easily contoured to the arch form and ligated with stainless steel wires passed around the


arch bar and the necks of the adjacent teeth or it can be bonded directly to the tooth

surface using acid etch technique. Cleats for intermaxillary fixation are also an integral

part of the design.

Advantages

These are useful where orthodontic treatment has not been used.

No technical assistance since it can be easily adapted into the desired shape, can be

placed before the operation, occlusion can always be checked and at the end of the

fixation period the arch bars can easily be removed without an anaesthetic.

Disadvantages

An adequate number of suitable teeth are required to get rigid and reliable fixation.

They may not be suitable in osteotomies where there are many crowns and bridges.

5. Eyelet wires. temporary intermaxillary fixation (IMF) is very important to secure the

mobilised segments of the maxilla and the mandible whilst applying the internal fixation

plates and screws.

6. Intra-oral intermaxillary fixation (Temporary IMF)

Temporary IMF is required at operation to achieve and hold the correct occlusion during

osseous fixation. There are several methods available:

1. Fixed orthodontic appliances with occlusal wafers

2. Arch bars

3. Cortical screws and intermaxillary fixation


b. Intra-osseous fixation.

1. Rigid internal fixation (RIF): RIF is the most common method of fixation. It includes:

i. Mini-plates (titanium or absorbable plates)

Adapted to the lateral surface of the jaw bone and secured with monocortical screws

(titanium or absorbable screws)

The introduction of L-and Y-shape plates should eliminate apical damage when

screwing into the maxillary alveolar segment.

ii. Bicortical screws (positional screws) (titanium or absorbable screws)

It passes through both the lateral and medial cortices.

A bicortical screw (also known as positional screw) is a fully threaded screw that

binds both the lateral cortex of the distal segment and the medial cortex of the proximal

segment during a bilateral sagittal split osteotomy (BSSO).

This method of fixation does not place any compression on the bony contact between

the proximal and distal segments as the screw is tightened; the screw engages both the

lateral and medial cortex, while maintaining the distance between the two cortices.

It is recommended that, for a BSSO to achieve maximum stability, three screws are

used and placed in a triangular pattern. Sometimes a percutaneous approach is advised

using a trocar to achieve the perpendicular placement of the screws.

It has been suggested that the use of bi-cortical screw fixation in mandibular

advancement procedures can lead to condylar resorption; torque may be applied to the

mandibular condyle through lateral displacement of the proximal fragment as the screws

are tightened. However, studies by Hoppenreijs et al (1998) and Hwang et al (2000) have

found that there is no significant difference in the incidence of post-operative condylar


resorption following BSSO fixation with transosseous wiring, positional screws or mini-

plate fixation.

NB: In a recent Cochrane review, it was concluded that there is no statistically

significant difference in post-operative discomfort, level of patient dissatisfaction, plate

exposure or infection for plate and screw fixation using either titanium or resorbable

materials in orthognathic surgery (Federowicz et al. 2009). Despite this finding, however,

resorbable plates are not widely used in the UK because of the concerns outlined.

Advantages of RIF

Primary bone healing due to intimate contact of the bony segments and rigid

immobilisation

Greater contact between the bone and screw improve mechanical and functional

stability

Direct and precise anatomical reduction

Evaluation of the post-operative occlusion at operation

Rapid return of jaw function

Improved oral hygiene

Improved comfort and convenience

Increased safety in the immediate post-operative period, eliminating the need for

intermaxillary fixation and for HDU/ ITU admission.

Shorter hospital stays.


Disadvantages of RIF

Expense

Technique sensitive

Damage to vital structures if placed in an incorrect site e.g. mental nerve, infraorbital

nerve

10-15% of plates require removal

Inflammation of overlying soft tissue which may result in soft tissue dehiscence.

Loss of elasticity of the bony segments.

Bulk - plates can sometimes be felt beneath oral mucosa

2. Transosseous wiring

Before the technique of direct rigid fixation with mini-plates was introduced,

transosseous wiring was the traditional method of immobilising bony segments (together

with supporting intermaxillary fixation IMF).

In the mandible, 0.5mm soft stainless steel wire is passed through the medial and

lateral cortices at either the upper or lower border during a BSSO procedure.

In the maxilla, 0.35mm wire is used because of the thinner nature of the maxillary

cortical bone.

In cases where bimaxillary osteotomy is carried out, skeletal suspension wires are

added from sites with denser cortical bone such as the piriform rim in the maxilla, and

circummandibular wires in the mandible.

c. Hybrid type: Cortical screws and intermaxillary fixation: Where there has been no

recent orthodontic treatment, a cortical screw placed in the buccal alveolus in each

quadrant or some form of arch bar is essential for intraoperative fixation of wafer.


Rigid internal fixation (as compared to intermaxillary fixation)

Advantages

1. Elimination of six weeks of IMF, so no need for time in intensive care

2. Early mandibular opening is possible.

3. Earlier return to a good diet

4. Better OH.

5. A very early revelation of any significant malposition of a jaw enables an early return

to the operating theatre before fibrosis starts. With rigid fixation the question arises very

soon after operation and not six weeks later on release of IMF.

6. Generally better final bony stability (e.g. Blomqvist et al 1997 and Forsell et al 1992)

Resorbable screws and plates

These screws are made from polylactide with or

without a percentage of polyglycide.

Ferretti and Reyneke (2002), compare them with

normal RIF screw and found no difference in the

post-operative stability.

It mainly used to overcome the disadvantages of

metal fixation include unacceptable palpability,

exposure intraorally, passive migration, and distortion of future magnetic resonance

images (MRI) and computed tomograms (CT). Titanium particulate matter may be shed

into the adjacent tissues and has also been found in regional lymph nodes. The ideal

bioresorbable material should not only support the bony fragments during healing but

also resorb fully once healing is completed. The resulting metabolites should not cause

any local or systemic disorders. LactoSorb is a copolymer of poly-l-lactic and


polyglycolic acid, in a ratio of 82:18%. The copolymer is structured to provide adequate

strength for 6–8 weeks and to allow a resorption time of 9–15 months. It is metabolised

in the citric acid cycle and eventually excreted by the lungs as carbon dioxide and water.

No difference in the degree of relapse between the use of bioabsirbable and metallic

screw after BSSO (Mattew and Ayoub 2003)

Cortical screws and IMF

These are an option for use in orthognathic patients with aligned and levelled arches

requiring no pre-surgical orthodontics.

Advantages include avoidance of intra-operative debonding of brackets (especially if

there is a heavily restored dentition) when the surgeon places the temporary IMF and the

elimination of hooks which can snag on surgical gauze and swabs.

Temporary IMF screws are placed in all four quadrants usually between the canine

and the first premolar teeth. Elastic or wire IMF is used. The screws can be retained for

post-operative elastic use and can be removed easily under local anaesthetic (Thota and

Mitchell 1999).


Medication for Orthognathic cases

Preoperatively Immediate postop Up to 3 days

Amoxicillin 1G intravenously at

induction

500 mg

intravenously 3

hours

orally 500 mg 8-

hourly for the

traditional 3 days

Metronidazole 1g rectal suppository

at induction

1g rectal

suppository

3 hours

400 mg orally 12-

hourly for 2-3 days

Clindamycin 300 mg

intravenously at

induction

150 mg iv. 3

hours

300 mg 6- hourly

orally for 2-3 days.

Dexamethasone for

swelling

8 mg is given

intravenously with

the anaesthetic

induction agents

8 mg is given i.v.

or i.m. 12-hourly

on postoperative

day 1

4-5 mg 12-hourly on

day 2

non-steroidal anti-

inflammatory analgesic,

A rectal

administration such

as flurbiprofen 150

mg 12-hourly, is also

useful to avoid

continuous opiate

analgesia.

non-steroidal anti-

inflammatory

analgesic,

Morphine for Pain 1 mg/ml by a Patient Controlled long-acting local


Administration “pump” system. analgesic 0.5% (5

mg/ml) bupivacaine

hydrochloride with

adrenaline (1:200

000)

antiemetic such as

metoclopromide

10 mg with morphine

Postoperative Care

First hour after surgery

1. A nasopharyngeal tube is left in situ overnight, with strict instructions to staff to suck

out the nasopharynx every 30 minutes with a fine catheter passed through the tube to

minimize vomiting.

2. Oxygen (40%) in air is usually administered by face mask at approximately 5

litres/min.

3. The patient should only be discharged from the recovery room once specific criteria

have been met:

I. The patient is fully conscious, responding to verbal or light touch and is able to

maintain a patent airway with a normal cough reflex.

II. Respiration and oxygen saturation rates are within acceptable limits (12–14 breaths

per minute, SpO2 >94% in a patient with no respiratory co-morbidity).


III. The cardiovascular system is stable with no unexplained arrhythmia and no ongoing

bleeding. The patient should have a heart rate and blood pressure that are closely aligned

to their preoperative values.

IV. Pain and emesis should be controlled and suitable analgesic and anti-emetic regimens

should be prescribed.

V. Temperature should be within acceptable limits.

4. If the patient does not achieve these criteria then they should be urgently seen by the

anaesthetist/ surgeon responsible for the patient’s care and consideration given to

escalation to a level 2 or 3 environment for further management.

5. Feeding and Postoperative Nutritional Support

Fluid balance, i.e. blood and fluid replacement should approximate to blood and fluid

loss.

Nutrition. During the first 24 hours continue the Hartmann's solution, 2 litres i.v., but

try 100 ml/h water by mouth, then tea or orange juice, etc. as soon as the patient can

tolerate feeding, using a syringe and quill, feeding cup or straw. If this is not possible use

a fine-bore (Clinifeed — Roussel, UK) nasogastric tube which should be passed

preoperatively to permit feeding until the patient can accept fluid and calories by mouth.

Malnutrition is a well-recognised problem in hospitals, with 40%-50% of all patients

found to be malnourished on admission and 70%-80% on discharge.

Consequences of malnutrition for the postoperative patient include decreased wound

healing, decreased immune function and increased infection risk which can lead to

unnecessary morbidity.

Optimum Daily Requirements, Men and women average 2000-3000 kcal. 0.8 g

protein/kg; 2-3 litres fluid.


6. Occlusion and elastic fixation if used.

7. Oral hygiene with Chlorhexidine 0.2% solution is commenced.

Second Postoperative Day

Repeat the above but change from intravenous to an oral or nasogastric regimen,

increasing the feed to a full diet.

Follow-Up

1. The occlusion may be checked weekly or fortnightly.

2. It is reassuring for the surgeon to assist maximal intercuspation with the final wafer

and elastics.

3. Soluble sutures should be left or removed when they are accessible and are a source of

irritation.

4. Patients require reassurance that impaired labial or infraorbital sensation will return to

normal within 6 months and that excess soft tissue will also remodel and disappear over

this period.

Immediate Postoperative Feeding

1. 0-24 Hours Post-Operation: Intravenous Fluids compound sodium lactate

(Hartmann's) solution is given to balance vomited fluid, gastric aspirate, urinary output

and metabolic needs. The volume will be 2 to 3 litres depending on the patient's weight

and the ambient temperature. The patient should also be encouraged to drink a little.

2. After 24 Hours

If the patient is well, and the surgical procedure allows, trials of oral fluid should be

commenced using a feeding cup, straw or a large bore syringe and quill. Most

orthognathic cases can cope,


if oral intake is proving difficult, enteral feeding should be commenced using a fine

bore nasogastric feeding tube. Supplemental intravenous fluids are often needed

3. After 48 Hours Patients who have commenced nasogastric feeding should continue to

receive this until the optimum oral intake has been established. Patients who have

tolerated oral fluids from the start can progress to a full diet. In many cases of bimaxillary

surgery involving the lower labial sulcus with impaired mental sensation, adequate oral

feeding may not be possible for up to 7 days and need special attention.

4. On Discharge the patient should have a comprehensive assessment and education

regarding food preparation, food fortification and the use of dietary supplements.

General Guidelines for Patients’ nutrition

Aim for weight maintenance.

Aim to include as much variety in the diet as possible

Liquids are more filling than solids, so more will be needed to prevent weight loss.

Liquidised foods must be thin and smooth enough to pass through a straw or quill.

Foods are often more palatable if liquidised separately to preserve individuals flavours

and colours.

Milk is a useful source of protein and calories, and can be fortified further by adding

dried milk powder; 3-4 tablespoons of any dried milk powder to 1 pint of full cream milk.

Vitamin C is an important nutrient for wound healing; a glass of pure orange juice or

blackcurrant drink should be taken daily.

This diet also requires a dedicated oral hygiene regime with a child's soft tooth brush

and a chlorhexidine mouth wash after meals to control plaque.


Problems of orthognathic surgery treatment

A. Orthodontic

1. decalcification,

2. breakage of tooth in debonding,

3. attrition with ceramic bracket,

4. root resorption,

5. alveolar bone loss,

6. pulpitis,

7. pulp obliteration,

8. gingivitis,

9. failed treatment,

10. stopped treatment,

11. relapse

B. Surgical

A. Intraoperative

1. Damage to the neurovascular bundle

2. Hemorrhage

3. Failure to relocate the osteotomised fragments

4. Damage to the teeth


5. Death

6. An unfavourable split can occur when osteotomies are not complete and the split is

forced despite increased resistance. The problems lie mostly in:

Incomplete osteotomies of the inferior border of the mandible as this area is composed of

thick cortical bone. The osteotomy should include a few millimetres of the lingual surface

of the mandibular margin to facilitate an uncomplicated split.

It is also possible but less frequent that the coronoid process is fractured, particularly if

the mandibular ramus is very thin and the osteotomy is carried out too buccally in the

ramus area. In this case the surgery can also be salvaged by completing the split in the

correct way and fixing the coronoid process to the proximal segment as described above

In very rare cases the bad split can be very high and it can involve the condylar process,

which is much more difficult to fix. Depending on the surgical situation a trans-oral

repair with endoscopic support is sometimes possible but otherwise a trans-cutaneous

approach or conservative management with wire IMF for 6 weeks can be considered.

Postoperatively

1. Immediate surgical complication including

a. Swelling,

Oedema is reducible with pre-and postoperative dexamethasone and antibiotic cover.

Contrary to some popular practice vacuum drains can dramatically reduce the swelling

arising from mandibular osteotomies, and the minivacuum drain is equally valuable for

infraorbital haematomas following dissection through a subciliary incision.

The same applies to the iliac crest donor site. Where possible leave drains for at least

24 hours after they cease to function.


Where there is gross postoperative swelling and pain, the presence of a haematoma is

more likely than oedema alone. Treatment should be the release of the haematoma,

especially if expanding, as it may be the presenting feature of a persistent arterial bleed,

which needs to be identified and arrested.

Approximately 60% of the swelling had resolved by 1 month following surgery with

100% resolution taking up to 6 months (Lee et al. 2006)

Resolution of swelling is also not symmetrical with one side often settling quicker

than the other.

b. Bleeding Problems

Minor Haemorrhage

Even with previously healthy patients not receiving any medication which would

predispose to excess bleeding, intraoperative blood loss is significantly reduced by the

administration of an antifibrinolytic agent such as tranexamic acid 25 mg/kg orally or

0.5-1 g by slow intravenous injection pre-and postoperatively.

Tearing the periosteum on the medial aspect of the ascending ramus whilst exposing it

for a sagittal split may produce a troublesome bleed, which can be controlled with a hot

wet tonsil swab and pressure for 3 minutes.

Damage to the facial vessels through the base of the subperiosteal pouch prepared for

the mandibular buccal cortex cut responds to the same pressure and patience.

Rarely the maxillary, tonsillar or lingual arteries may be damaged, giving rise to

prolonged serous haemorrhage. Again, packing firstly with a swab, and secondly with a

large piece of oxidised cellulose (Surgicel) should be sufficient, assisted by 0.5-1 g t.d.s.

tranexamic acid (Cyclokapron, Kabi) given intravenously.

If vigorous bleeding persists the external carotid may need to be tied off.


Persistent Haemorrhage

Severe haemorrhagic complications have been reported in up to 2.2% of cases. Failure to

control bleeding despite efficient conservative measures may be due to the following:

i) A patent damaged artery, either the maxillary or tonsillar that require identification

and ligation. Do not delay ligation of the external carotid if significant bleeding persists

despite local ligation, packing and antifibrinolytic therapy for more than 30 minutes. This

should allow time for investigation.

ii) A rare manifestation of a latent coagulation defect or defibrination. In both cases there

is an evident lack of clot formation on the drapes and the wound oozes “watery blood”.

Secondary Haemorrhage

The patient may suddenly bleed profusely postoperatively in the ward, or even at

home. The common causes are a partially divided large vein or untied artery in the depths

of a mandibular osteotomy wound.

Occasionally an undetected coagulopathy such as von Willebrand's is the underlying

problem, especially when the bleeding is repeated. The management must commence

with pressure applied to the bleeding site with swabs, and rapid transfer to theatre for

exploration and haemostasis, as described. As with all severe haemorrhage up to 10 mg

intravenous morphine should be given immediately by slow intravenous injection as a

sedative analgesic, together with tranexamic acid 0.5-1 g intravenously to help conserve

clotting factors and clot in favour of haemostasis.

Perioperative systemic anticoagulation therapy can, however, aggravate this problem

and therefore it is advisable not to commence any anticoagulation with heparin or similar

medications for 24 hours postoperatively if medically justifiable.

Gastric Haemorrhage


The chance of stress-induced gastric erosion is small, even after prolonged orthognathic

surgery. However, the combination of a patient with a history of peptic ulceration, a

stressful surgical procedure, anti-inflammatory steroids and analgesics can produce a

gastric bleed. Abdominal discomfort, tachycardia, true melaena and/or haematemesis and

a fall in haemoglobin (a late sign) should alert one to this possibility. Initial treatment

should include intravenous fluid support and administration of a proton-pump inhibitor

(omeprazole), first as an intravenous bolus dose (40 mg), then as an intravenous infusion

for 72 hours. Early endoscopy should be considered after consultation with a

gastroenterologist so that the bleeding point can be injected or banded. The aim of drug

treatment is to raise gastric pH to above 4, thereby stabilising any clots that may have

formed at the bleeding site. This is the reasoning behind the use of proton pump

inhibitors over H2 receptor blockers such as ranitidine, which have a lesser effect on pH.

With vulnerable patients a regular prophylactic proton pump inhibitor, such as

omeprazole or lansoprazole, should be administered as well as eliminating both steroids

and non-steroidal antiinflammatory analgesic drugs from the intraoperative and

postoperative regimen.

c. The Airway

After an uneventful operation, the airway should be maintained with a nasopharyngeal

tube, which is sucked out throughout the postoperative 12-18 hours at 30-minute

intervals. Unless the nurse ensures that the fine suction catheter passes beyond the end of

the nasopharyngeal airway tube, the end will gradually become blocked with blood clot

and will become an efficient airway obstruction the same can occur with a tracheostomy

tube.

Some anaesthetists leave an endotracheal tube in situ which with modern closed

suction units can be kept unobstructed with minimum effort and nursing intervention. A


facemask with 40% oxygen at a flow rate of approximately 5 litres/min ensures adequate

tissue perfusion.

Nasal obstruction with blood clot and mucous crusting can be prevented by steam

inhalations containing Friar's Balsam or some similar aromatic vapour.

Occasionally an asthmatic patient develops acute bronchospasm and airway

obstruction despite the dexamethasone cover. This may be resolved by a salbutamol

nebuliser; 2.5-5 mg of salbutamol in a pre-prepared solution via a nebuliser mask on 8

litres oxygen per minute repeated as required

Emergency Airway Procedures. Acute upper airway obstruction is more likely to

follow trauma than elective operative procedures. In the non-intubated patient,

obstruction secondary to haemorrhage into the neck tissues may prevent the clinician

from inserting an endotracheal tube through the cords to establish airway patency. In such

cases needle cricothryroidotomy and surgical cricothyroidotomy may be used to maintain

ventilation and oxygenation whilst formal endotracheal intubation is attempted.

Needle cricothyroidotomy and jet insufflation can provide supplemental oxygenation

for around 20-30 minutes, the time constraint being carbon dioxide retention, as only

minimal expiration is possible through the obstructed airway via this method. This

relatively simple technique buys time to perform more definitive airway procedures by a

clinician skilled in difficult and emergency situations.

Surgical cricothyroidotomy involves the insertion of a small endotracheal tube or

tracheostomy tube through the cricothyroid membrane. Using this method the patient can

be successfully oxygenated and ventilated with a bag valve system with supplemental

oxygen until intubation or retrograde intubation is achieved.

It can be aggravated by postoperative IMF and should this be the case, release of the

IMF can solve the problem.


d. Soreness,

e. Difficulty eating,

f. Bruising,

g. Mild post-operative depression.

h. Pneumothorax

Occasionally, despite every care on removing a rib graft, there is a breach in the pleura

and the patient develops a pneumothorax. The presenting signs are breathlessness and

tachypnoea with absent breath-sounds over the area. The typical radiographic appearance

where the visceral pleura is breached. The most convenient, comfortable and

cosmetically pleasing site for drainage is in the fourth or fifth intercostal space in the

mid-axillary line.

i. Vomiting Postoperative

Vomiting in patients with intermaxillary fixation was a well-recognised problem.

Predisposing factors are blood escaping intraoperatively and postoperatively into the

stomach, where partial digestion together with bile reflux creates an irritant stagnant

mixture. An additional factor is the emetic effect of opiate analgesics. Prevention

Avoid intermaxillary fixation by using internal rigid fixation.

ii) A 12-16FG nasogastric tube passed at the time of the anaesthetic induction enables

postoperative aspiration of gastric contents. The tube is attached to a bile bag to create a

closed collecting system for any spontaneous reflux. As the patient is monitored

throughout the postoperative night the stomach should be aspirated hourly and the fluid

loss noted. Initially flushing the tube with 20 ml water before aspiration prevents the end

becoming clogged with clot.


The administration of an antiemetic, e.g. metoclopromide 10 mg intravenously at the

end of the operation, and with any required opiate analgesics, reduces drug-induced

emesis (up to a maximum of 30 mg/24 hours). Metoclopromide 10 mg intravenously

should also be given at any other time if vomiting is anticipated.

j. Iliac Crest Problems

The removal of bone from the iliac crest for orthognathic purposes is becoming less

popular. However, the inverted L osteotomy may require a substantial amount of

corticocancellous bone to correct a very small mandible. Postoperative pain is the most

frequent complication and can be reduced by drainage and analgesics. Some surgeons

leave a fine cannula for infusion of a long acting local analgesic such as bupivacaine

(Marcain). It is difficult to be certain if this is of significant value. If a large graft has

been removed near the anterior superior iliac spine, this may fracture with sudden

movement once the patient is mobilised.

k. Urinary retention

Catheterisation Catheterisation is necessary for prolonged surgical procedures, especially

where large quantities of fluid have been infused. This is uncommon with orthognathic

cases except where there has been unexpected major blood loss. Another occasional

indication is the patient, usually male, who has postoperative urinary retention. This may

be due to opioid-induced sphincter spasm, diffidence in using a urinal, or a combination

of both, leading to gross distension.

l. Deep Vein Thrombosis

This is a rare event in orthognathic patients, usually occurring unexpectedly in young

women.

As a precaution, all women should cease taking oestrogen containing contraceptive

pills 4 weeks prior to surgery.


If this has been overlooked, subcutaneous low molecular weight heparin prophylaxis

should be considered,

Both high and low risk patients benefit from elasticated thromboembolic-deterrent

stockings being worn during the operation.

Any complaint of postoperative calf tenderness must be taken seriously, lower limb

Doppler ultrasonography should be carried out and if this is positive (or not possible) the

patient is anticoagulated to prevent extension of the thrombus and embolism.

m.

2. Late complications:

a. Failure of bony union

b. infection of the surgical plates 10%,

c. Soft tissue problem:

increase alar width and fullness of upper lip with maxillary impaction

double chin with mandibular set backs

lip sag following augmentation genioplasty

d. Fixation Problems

Infection may occur around screws and plates. Miniature plates are an essential part of

the osteotomy and surprisingly in the maxilla rarely get infected. If drainage and a course

of antibiotics do not suppress the infection, the plate and screws have to be removed.

Similarly, uninfected bone plates may become palpable subcutaneously or submucosally

and also require removal.


Incorrectly placed screws and plates may displace the bony parts. This occurs more

commonly in the third molar area with the sagittal split operation, but is also with Le Fort

I procedures where maxillary displacement can distort the nasal septum.

Less commonly plates break. Whenever displacement or loss of control takes place,

the patient should be taken back to theatre for correction.

If the condyle is pushed to the back of the fossa when temporary intermaxillary

fixation is put on to facilitate the insertion of the bicortical screws or buccal plate, on its

release, with the patient conscious and upright, the condyles will tend to recoil

downwards and forwards. This is favourable for the Class 2 Division I mandibular

advancement but gives a postoperative prognathous malocclusion with the Class 3

setback. To avoid these artefacts (a) the model surgery should be based on a conscious

supine centric relation squash bite and (b) the ascending ramus proximal fragment should

be displaced backwards for Class 2 advancements but pulled forwards prior to fixation

with the Class 3 mandibular setback. Such problems were less likely to happen with a

loose interosseous wire loop at the osteotomy site and prolonged intermaxillary fixation

for 6 weeks. This enabled the ascending ramus proximal fragment to achieve an optimum

condylemeniscus-fossa relationship by functional adjustment brought about by

swallowing and speech.

Disturbed muscular proprioception and intracapsular oedema may also give a transient

deranged postoperative occlusion when using rigid fixation. In these cases, light elastics

for 7 days will help to restore the occlusion to the planned relationship. The final

occlussal wafer is often left in situ even where there is no occlussal problem. This is very

uncomfortable for the patient and there is no evidence that it helps. However, if after this

elastic “proprioceptive regimen” there still appears to be marked displacement and

malocclusion — re-operate.

e. condylar resorption specially in high angle class II, specially on patients who has:


Posteriorly inclined condyles.

Deliberately increased maxillary-mandibular plane angle.

Reduced posterior face height.

As this may result in an increased risk of progressive condylar resorption following

surgery, with subsequent relapse of the malocclusion (Hwang et al., 2004).

f. Relapse (see stability section)

g. Occasionally lower lip sag may follow a bone graft procedure to increase the chin

depth by augmentation, or a mandibular forward movement with a genioplasty. It is

difficult to be sure whether it is due to inadequate freeing of the periosteal pouch and

overlying soft tissues, or failure to re-attach the mentalis high enough on the anterior

mandibular surface, or abnormal muscle activity. The lip sag should be avoided by the

creation of a large loose periosteal pouch to accommodate the enlarged chin, carefully

suturing the divided mentalis to the deep muscle fibres on the alveolar surface, and the

application of a firm pressure dressing overlying the labiomantal groove. Once formed it

can be eliminated in some cases by vigorous exercising of the lower lip, i.e. the lip is

actively stretched upwards over the incisor edges. If this fails, it will be necessary to

deglove and reposition the soft tissues upwards using heavy polyglycollate (Vicryl)

sutures to elevate the soft tissues of the chin.

h. Idiopathic periapical and internal resorption may occur in teeth adjacent to an

osteotomy cut, even without untoward bur contact. The cause is unknown but may be due

to a vascular response to the adjacent surgery.


i. Orthodontic depression of lower incisors in adults, before surgery, may cause

proclination with alveolar dehiscence and gingival recession. Furthermore, the proclined

incisors may then upright spontaneously once fixation is removed.

j. Tooth damage may occur with the bone cuts of segmental osteotomies, either apically

or laterally. Avoid the former by marking the estimated apical site with a shallow bur

hole prior to the section. Lateral root damage arises when burs are used interdentally.

Only the buccal and lingual (palatal) bone should be cut with a bur and the actual division

should be made with a fine osteotome or saw. Although root damage often appears to be

self-limiting and most teeth survive, occasionally the exposed dentine undergoes

progressive resorption. An attempt may be made to preserve the tooth by root canal

therapy with calcium hydroxide. However, should root loss progress, extraction and an

implant or bridge will be required to salvage the situation. Segmental cuts in the older

patient with incipient periodontal disease may also create intractable bony pockets unless

anticipated. The cuts must be done carefully with a fine osteotome after prior periodontal

therapy followed by postoperative oral hygiene instruction.

k. Nerve Damage

l. It is important to warn the patient preoperatively of impaired sensation that may arise

in the mental or mylohyoid nerve distribution of the lower lip and chin following a

sagittal split or anterior segmental operation, and in the infraorbital area following a

maxillary osteotomy. The former usually recovers in 2-6 months, although some patients

have a permanent deficit, which is less noticeable if the operation is otherwise successful.

When the inferior dental nerve is exposed and torn during the sagittal split, it may be

possible to hold the separated ends together with a 6/0 Prolene suture prior to fixation.

Permanent damage to nerve, 20-25% risk of permenant altered sensation with BSSO. The

literature suggests that sensory deficit is more likely to have a higher incidence in older


patients, in patients undergoing large advancements or if the sagittal split osteotomy is

combined with a genioplasty

i) Facial nerve damage with weakness can be localised following external incisions for a

subsigmoid (subcondylar) osteotomy but will involve a wider distribution of the facial

nerve if it is damaged near its main trunk. This can occur with a sagittal split pushback or

an intraoral subsigmoid (subcondylar) operation. The cause is probably traumatic

instrumentation. They prognosis is usually very good, with gradual recovery over 6-8

weeks.

ii) The lingual nerve is rarely damaged during an osteotomy. However, persistent

impaired lingual sensation after 6 weeks requires open exploration and repair. This is

most easily done by removing the overlying sublingual salivary gland.

iii) A rare disturbance is nasal vasomotor hyperfunction, which may occur after a Le Fort

I osteotomy. The patient develops continuous rhinorrhoea, which look like but not a

cerebrospinal fluid leak. The cause is uncertain and may be either loss of sympathetic

vasomotor control or damage to the sphenopalatine ganglion with enhanced stimulation.

There is no satisfactory treatment.

iv)There can also be indirect nerve weakness by excessive postoperative swelling.

m.Emotional and Psychiatric Problems

Agitation can arise both from intolerance of intermaxillary fixation or simply nasal

airway obstruction. Both can now be avoided.

Unanticipated anxiety of an alien environment, especially the intensive care unit,

Emotionally unstable individuals, especially those who have a history of body

dysmorphic disorder, may also become aggressive.


Postsurgical orthodontic

The aims of postsurgical orthodontics are:

1. Final tooth positioning

2. Root paralleling

3. Vertical movements of buccal segments with inter-arch elastics. In the arch where

most vertical movement is required, a more flexible archwire may be used such as

rectangular nickel titanium or rectangular braided steel wire. In the opposing arch where

vertical movement is not required, a stiffer rectangular steel wire can remain in place

4. In cases of segmental surgery, where canine brackets have been reversed

preoperatively, it is necessary to re-bond the canine brackets, placing brackets of the

correct side in order to produce a normal canine angulation.

5. Retention

Orthognathic Surgery

The aetiology of relapse

1. Dental relapse

Upper incisors are proclined by the lower lip after a maxillary segmental pushback

procedures is carried out on a marked Class II, Division 1 patient without a mandibular

forward correction to an edge to edge relationship.

Continued eruption (occlusal drift) of the lower incisors will follow an anterior segmental

setdown unless they are placed in a stabilising contact with the cingula or incisive edges

of the opposing teeth.


Expansion of the maxillary premolar and molar segments may tilt those teeth buccally.

Subsequent palatal drift will produce intercuspal contact on closure with the creation of

an anterior open bite. Major expansion of the palate should be done surgically with a

midline osteotomy to avoid dental relapse.

Repositioned lower incisors are proclined by a large or “anteriorly postured” tongue.

2. Surgical relapse: incorrect osteotomies with improper seating of the condyles. It arises

from inadequate planning or inappropriate surgical technique. The latter may be roughly

divided into two overlapping groups:

A. Operative Structural Causes of Relapse

Inadequate separation of the proximal mandibular bone and the medial pterygoid muscle

from the buccal plate when doing a sagittal split. A finger firmly inserted to the depth of

the split is used to remove the restraining periosteum and muscle fibres, which hold the

two cortices together at the lower border.

Inadequate bone removal from the posterior wall of the antrum or separation of the

pterygoid plates in a Le Fort I impaction can also create problems.

The untrimmed nasal septum will create a buckling effect and either displace the maxilla

and disturb the occlusion, or displace the nose and produce an asymmetric tip deformity,

and obstruct the airway. Late correction will require a rhinoplasty.

B. Postoperative Functional Causes of Relapse: The most notorious is the recurrent anterior

open bite following attempted correction with a mandibular osteotomy. This will occur in

patients with a high mandibular-maxillary plane angle where the low posterior facial

height reflects a short pterygomasseteric sling. This is stretched as the mandible is rotated

around the fulcrum created by the occluding molar crowns when the anterior teeth are

brought into occlusion to close the gap. The inelastic ligaments and the return of

postoperative muscular tone may even produce a relapse despite internal fixation. This is


avoided by a posterior maxillary impaction equivalent to the anterior open bite to be

corrected.

3. Skeletal relapse due to bone remodelling

4. Soft tissue and muscles relapse

5. Growth relapse

6. Habit

Stability depends on

1. Surgical technique employed

2. Direction of movement

3. Magnitude of movement

4. Type of fixation used.

5. Adaptive capacity of muscle fibres

6. Buccal interdigitation

A hierarchy of stability (Proffit 1996, 2007)

A. Superior repositioning of the maxilla and mandibular advancement is the most stable

procedure


B. Forward and asymmetrical movement of the maxilla is reasonable stable with or

without RIF in short or normal face height

C. Bimaxillary and mandibular rotation relatively stable with RIF only

D. Mandibular setback is not stable, if the ramus is pushed to a more vertical inclination

when the chin is moved back, the mandibular musculature tends to return the ramus to its

original inclination when function resumes and carries the chin forward again. The

principal circumstance in which neuromuscular adaptation does not occur is when the

pterygomandibular sling is stretched during mandibular osteotomy

E. Downward movement of maxilla is also problematic (relapse 20%) due to forces from

occlusion, three approaches has been suggested to improve stability of maxillary

downward movement:

Placement of heavy fixation bars from the zygomatic arch to maxillary posterior teeth,

Interposition of synthetic hydroxyapatite graft

Use of simultaneous ramus osteotomy to minimize stretching of the elevator muscles

F. Transverse widening of the maxilla is the least stable procedure, due to stretches of the

palatal mucosa and its elastic rebound is a major cause of relapse

A different pattern of stability is evident after twelve months once surgical healing is

complete.

1. Mandibular advancement is associated with some decrease in length,;

2. Maxillary superior positioning will relapse by > 2-mm in a 35% of patients;

3. Significant changes occur in jaw positions after bimaxillary surgery, but these are not

necessarily reflected in changes of overjet or overbite bec the dentoalveolar adaptation

prevents an increase in overjet in more than half these patients


4. Class III correction are more stable in the long-term than class II.

5. As a general role, late relapse >lyr post op in 2.5-8% of patients,

Stability following clockwise (CW) or counterclockwise (CCW) rotation

It has been suggested that closure of anterior open bite by counterclockwise

rotation of the mandibular distal segment can compromise the stability of the case,

however, long term studies have shown similar risk in open bite cases where a posterior

maxillary impaction and autorotation is achieved with or without mandibular surgery.

Espeland et al showed that surgical improvement of anterior open bite by 1-piece

maxillary osteotomy was usually stable over a 3-year period and that maxillary vertical

skeletal changes through the postsurgery period were compensated by orthodontic

dentoalveolar adaptation. Most of the skeletal relapse occurred during the first 6 months

after surgery and always in the direction opposite to the surgical movement. Teittinen et

al, delivered similar results with a tendency for the overbite to increase gradually

following maxillary impaction with or without mandibular surgery

Controversies still exist regarding the CCW approach done with a single or

double-jaw surgery

There is tendency to relapse with both clockwise (CW) or counterclockwise

rotation of the mandible

Variability in results and stability exist in both techniques

CCW approach may deliver better results if planned accounting with less than 8

degrees

Advantages of the CCW approach include


Limit surgery to a single jaw which also reduces the surgical costs.

Elimination of potentially adverse aesthetic soft tissue changes associated with

Le Fort I impaction.

Allows for greater advancement of the mandible

Airway enhancement by increase in the lateral and anterior–posterior airway

diameters at multiple sites particularly relevant in patients with obstructive sleep apnea

Minimizing the possibility of bite reopening following CCW surgery

Poulton and Ware proposed two methods of minimizing the possibility of bite reopening

following surgery.

Limiting the rotation to 8 degrees only

Planning a posterior open bite into the surgical splint to achieve overcorrection, the

patient continued to wear an occlusal splint after the fixation was released employing a

gradual reduction of the posterior part of the splint allowing the molars to erupt as the

muscles readapted to the new mandibular position and maintaining the incisor overbite.

Amore direct way of minimizing the early effects of soft tissue and muscle pull was the

use of a neck brace. A later study failed to show that this latter technique was of any

value for preventing relapse in mandibular advancements with the bilateral sagittal split

osteotomies.

Upper border wire: surprisingly no study has been published looking specifically at the

stability of mandibular advancements using bilateral sagittal split osteotomies stabilized

with wire osseous fixation combined with intermaxillary fixation.

Kahnberg did describe success in treating Class III patients with anterior open bite using


a vertical ramus osteotomy (VRO) but this success has not been shown since.

Using inverted ‘L’ osteotomy with bone graft through a skin incision

TADa to intrude upper posterior and autorotration

4 screws each side in the BSSO to increase stability

Modified short split BSSO by Epker where the muscles remain attached primarily to the

proximal segment and are minimally stretched, if at all, by the anticlockwise rotation of

the mandibular body

Stripping of the sphenomandibular ligament according to Beukes and Reyneke from its

attachment on the medial of the distal fragment has also been suggested although care

needs to be given to the inferior alveolar nerve and vessels if this is attempted.

Disadvantages of the CCW approach include:

• Borstlap et al. observed a relationship between the amount of advancement and

relapse, suggesting greater risk to those with a steep mandibular plane angle. The

authors also noted that young patients appeared to be in high risk for the occurrence of

condylar modification.

• Also, the experience of pain and TMJ sounds at the first few months

postoperatively are highly suspicious for condylar changes to take place in the next

months.

• Greater short and long term associated with both horizontal and vertical relapse

due to increased stress on the surgical segments.

Advantages of surgery first

Eliminate cuspal interference during expansion


Faster movement

Better teeth movement in the new ST environment

Repair imperfect surgery

Less impact on aesthetic during decompensation

Quick facial changes

Some advocate limited orthodontic i.e. part of orthodontic decompensation is achieved

before the surgery and the rest after surgery. The claimed benefits are to reduce the

negative effect of the de-compesatition phase and to get benefit from faster de-

compesatition secondary to surgery due to the effect of RAP and change soft tissue

envelop

Other Dental Treatment associated with orthognathic cases

Four special points should be considered when orthognathic surgery is involved:

1. Incision lines contract somewhat as they heal, and when incisions are placed in the

vestibule, this can stress the gingival attachment, leading to stripping or recession of the

gingiva. This is most likely to be a problem in the lower anterior area in relation to the

incision for a genioplasty .Gingival grafting should be completed before genioplasty if

the attached gingiva is inadequate.

2. If the surgeon will use rigid fixation (bone screws) placed in the third molar area, it

is desirable to have the teeth removed far enough in advance of the orthognathic

procedure to allow good bone healing (minimum 6 months). If the wisdom is extracted at

the time of surgery and the screw passed through the extraction socket, there will be high

chance of weak fixation and infection around the screw.

3. Orthognathic surgery has no influence on TMD. If joint surgery will be required,

usually it is better to defer this until after orthognathic surgery because the joint surgery

is more predictable after the new joint positions and occlusal relationships have been

established.


4. Definitive restorative and prosthetic treatment is the last step in the treatment

sequence

Facial deformity and the proposed treatment orthodontically and surgically

Mandibular Prognathism

Presurgical orthodontics will be required to

correct arch size discrepancy,

overcrowding

to decompensate the incisors.

Surgery:

sagittal split osteotomy,

oblique subcondylar (subsigmoid) osteotomy

a) extraoral,

b) intraoral (buccal approach),

c) intraoral (medial approach).

Mandibular Asymmetry (Unilateral)

Presurgical orthodontics will be required to

Insufficient maxillary intercanine width to accommodate the lower arch is common

which need an expansion.

with large discrepancies surgical expansion of the maxilla may be the treatment of

choice or distraction osteogenesis with a bone borne expansion appliance.


Surgery:

Asymmetry, with or without prognathism, can be corrected by a bilateral ramus

osteotomy, such as the sagittal split, which shortens the affected side and allows rotation

at the contralateral angle.

Recurrent growth creates a difficult decision and will require a careful high condylar

shave preserving the meniscus.

Hemimandibular Hyperplasia

Early

High condylar shaving

subsigmoid osteotomy with osteoplasty of the body of the mandible

Late

The most economical correction is simply reducing the lower border convexity. This

improves the facial appearance and corrects the obliquity of the mouth,

bimaxillary procedure elevating the maxilla with a Le Fort I osteotomy and the

mandible must then be adjusted to this horizontal occlusal plane, either by a sagittal split

or subcondylar osteotomy as well as the convex lower border will still need to be

trimmed.

Condylar Hypoplasia

Features:

1. Deviation of the chin to the affected side


2. The condyle is usually short, flattened or deformed.

3. An exaggerated antegonial notch is present on the affected side.

4. Deficiency in ramus height gives rise to a secondary canting in maxillary growth that

is tilted downwards towards the normal side.

5. Joint ankylosis

6. Greater asymmetry

Treatment

Moderate degrees

Moderate degrees of hypoplasia may be treated like an asymmetrical hyperplasia, with a

bilateral sagittal split osteotomy. This will lengthen the affected side and provide a

rotation adjustment on the normal side. However, the maxillary occlusal plane has to be

levelled first. In adolescence this can be achieved orthodontically after the mandibular

surgery by creating a lateral open bite intraoperatively with a unilateral thickened

occlusal wafer or splint.

A large unilateral deficiency,

The downward and forward mandibular reconstruction can only be achieved with an

inverted L osteotomy and interpositional bone graft or distraction osteogenesis . Again,

the maxillary occlusal plane will also require correction. If the patient is an adult, a Le

Fort I osteotomy will be necessary to level the transverse occlusal tilt

Mandibular Retrognathism or Hypoplasia

Treatment


Decompensation of the incisors and a forward osteotomy of the mandible to an

overcorrected edge to edge incisor relationship, giving a three-point contact occlusion,

i.e. incisors and distal molars, followed by orthodontic closure of the lateral open bites.

Separate orthodontic levelling of the canine and incisors, and the buccal segments.

This will be followed by a lower anterior mandibulotomy setdown carried out at the same

time as the mandibular lengthening procedure. This has the advantage of maintaining the

lower facial height.

Mandibular Incisor Proclination

the first premolars can be extracted and the canine-incisor segment brought backwards

with a Kole subapical (labial segmental) osteotomy.

If the tongue looks large, reduce it with the osteotomy. If there is any doubt, warn the

patient that should incisor proclination relapse occur, tongue reduction may be necessary

Maxillary Hypoplasia

Orthodontically: expansion of the intercanine is important

The treatment of choice is a Le Fort I osteotomy with a forward movement

the Kufner modification of the Le Fort III osteotomy produces an advancement of the

malar bones and infra-orbital margins

Nasomaxillary Hypoplasia

Le Fort II osteotomy


Malar Hypoplasia

the Kufner modification of the Le Fort III osteotomy

The Kufner osteotomy followed by distraction osteogenesis.

The alternative solution is a Le Fort I advancement with simultaneous alloplastic

malar onlays.

Maxillary Protrusion

Anterior segmental osteotomy (Wassmund/Wunderer). The canine-incisor segment is

set back after extraction of the first premolars. A midline split is necessary to maintain a

natural dentoalveolar arch.

Le Fort I setback, very difficult and limited.

Bimaxillary surgery

Traditional techniques

B. Initial bony cuts are completed bilaterally for mandibular sagittal-split osteotomy,

delaying the separation of the tooth-bearing segment of the jaws from the proximal

condylar segment.

C. The wounds arc packed with moist gauze

D. Then the leFort I osteotomy completed.

E. With an intermediate occlusal splint (or the combined two-stage splint) the maxilla

and the mandible are wired temporally by IMF and the maxilla is repositioned and

stabilized with RIF.

F. Then, At this point, the IMF is released.


G. Then Sagittal-split osteotomies are completed bilaterally in the mandible with

osteotomes.

H. The tooth-bearing segment of the mandible is repositioned, with the final occlusal

splint used as a guide. With the patient's teeth again held firmly together, a temporary

IMF is performed

I. Then the mandibular osteotomy sites are stabilized and fixed with RIF, then IMF

released.

Alternative techniques

A. Buckle, Tucker, and Fredette have suggested another sequence for two-jaw surgry.

B. The mandibular BSSO to be completed before LeFort 1 .

C. RIF with position or large screws provides stable, repositioned mandible.

D. The intermediate splint in this instance uses the intact maxilla as the guide.

E. With the mandible held in the new position with RIF, the final occlusal splint properly

repositions the maxilla after leFort I osteotomy.

F. The advantages are minimizes the chance of displacement of maxillary segments once

they have been repositioned specially when there is a difficulty in stabilizing the maxilla

after LeFort I osteotomy such as in repeat Le Fort I osteotomy or with a multi-segmented

maxilla.

The Deep Overbite

With a poor profile, consisting of a retrognathic mandible, increased lower facial

height and the lower lip trapped behind the upper incisors , treatment comprises

orthodontic decompensation of the incisors followed by a combination of a lower anterior

dentoalveolar setdown and a sagittal split osteotomy to bring the whole mandible forward

to an overcorrected edge to edge incisor relationship.

3 point landing BSSO


Secondary surgical correction for CLP patient

Important Factors to be considered

1. The amount of tissue in the original embryological defect: early cleft closure cause

more growth retardation

2. Preservation of tissue: Also important is the preservation of tissue, tissue removal

should be avoided whenever possible.

3. The nature and quality of the primary surgery: different surgical technique result in

different outcomes.

Specific Problems in Cleft Patients

1. Sever Class III skeletal problem in all direction with malar hypoplasia.

2. Anterior open bites are common

3. Posterior cross bites are common

4. Dental development may also be delayed in both arches but is most evident in the cleft

segment and may compromise the presurgical orthodontics.

5. The repaired alveolar cleft is a potential site for fracture at the time of the down-

fracture.

6. If the maxillary alveolus has not been reconstructed, alignment of the alveolus can be

incorporated into the orthognathic procedure. However it complicates the planning of the

surgery and increases the potential morbidity. Segmental osteotomies are less stable than

one-piece maxillary osteotomies.


7. Previous surgery produces scarring of the labial and buccal vestibule, the palate and

behind the maxillary tuberosities. This presents problems with the surgical incisions,

mobilisation and postoperative closure of the surgical wound.

8. A pharyngeal flap may make advancement of the maxilla difficult and will need to be

divided. The patient has to be informed well in advance about the possibility of VPI and

speech problem that might developed after the surgery.

Treatment Planning for CLP

The basic facial and orthognathic evaluation is the same as the non-cleft case with

important refinements.

1. Lip-incisor relationship. As in the non-cleft case, the lip to maxillary incisor

relationship is extremely important. The major surgical moves are predominantly in the

maxilla and with a tight, previously scarred upper lip, small skeletal moves have a

pronounced effect on the incisor exposure. Surgical and orthodontic changes in incisor

angulation will have a similar effect.

2. Asymmetries. Both dental and skeletal asymmetries are dominant features, often with

compensatory asymmetries in the mandible. This should be considered

3. Pharyngeal obstruction can be caused by hypertrophied adenoidal tissue or pharyngeal

flaps. Nasal airway obstruction may arise from a deviated nasal septum narrowing of the

nares, hypertrophied turbinates, nasal polyps and posterior choanal constriction from sub-

periosteal bone and asymmetrical vomer flaps. The management of these problems is an

essential part of the orthognathic procedure. Paradoxically the adenoid mass may

contribute to velopharyngeal function and its removal may precipitate velopharyngeal

inadequacy.

4. Preoperative speech assessment and counselling.


5. However, infection, bone and soft tissue necrosis, delayed healing, loss of teeth and

relapse all occur with greater frequency due to multiple previous surgeries.

The Choice of Operation for CLP

Maxillary Hypoplasia

1. LeFort I osteotomy either one piece or two pieces maxilla for transverse maxillary

widening.

2. High LeFort I level osteotomy.

3. The modified LeFort II and Kufner LeFort III osteotomy

4. SARPE

5. Rhinoplasty may be necessary.

6. Mismanagement of the soft tissues during closure of the labial vestibular incision may

cause shortening and thinning of the upper lip. The V-Y closure of a maxillary vestibule

incision may increase the vermilion show in patients with a thin upper lip.

7. Maxillary advancement widens the alar base, increases the projection and elevation of

the nasal tip and the width of the nares. Various surgical manoeuvres can be used to

prevent these unwelcome side effects. These include an alar base cinch suture,

recontouring the bony piriform aperture either by trimming and/or asymmetric bone

grafting and alar base resections.

Mid Face Distraction Osteogenesis

Indications:


With gross maxillary hypoplasia and a severe degree of scarring, the degree of

advancement may be beyond the expected limits of stability of a conventional osteotomy.

Distraction of the maxilla is preferable to a surgical compromise such as a mandibular

setback.

If the deformity is complex particularly in the upper mid face then a higher level

osteotomy with distraction often gives a better result than a modified LeFort I with

masking onlay bone grafts or modified LeFort II and LeFort III osteotomies that are

difficult to perform and can give unsightly steps particularly over the radix of the nose.

Mandibular setback (BSSO, VSO)

Mandibular set back indicated in case of:

1. Mandibular prognathisism

2. When there is a maxillary surgical limitations such as severe palatal scarring,

borderline velopharyngeal insufficiency or a tight inferiorly based pharyngoplasty flap.

3. During maxillary advancement and inferior positioning, the anterior maxilla is

differentially positioned more inferiorly. This will produce a posterior open bite

deformity unless a mandibular ramus procedure is undertaken simultaneously.

Differential down grafting of the anterior maxilla also results in a counter clockwise

rotation of the mandible which may make the chin retrogenic. This can be corrected by a

simultaneous augmentation genioplasty.

Airway Considerations for CLP during surgery

1. The surgeon can do the following whilst the maxilla is down fractured

Contouring of the inner aspects of the nose


Asymmetries in the piriform region

The mucosa of the nostril floor can be repaired

Septoplasty may be indicated

Partial or complete inferior turbinectomies

Antral and nasal polyps can be removed

2. Pharyngeal flaps raise additional concerns for the anaesthetist and surgeon which may

make intubation difficult and restrict the nasal airway, so submental intubation might be

indicated

Postoperative considerations for CLP

1. Speech therapy: The soft palate mechanism in non-cleft patients has considerable

reserve capacity and can adapt to an increase in length. The repaired cleft soft palate does

not have this capacity to adapt especially after major advances. The patient with

borderline velopharyngeal incompetence preoperatively is likely to develop worsening of

their speech postoperatively.

2. Relapse: As a prophylactic measure, extraoral elastic traction using a face mask can be

used in patients who are considered particularly at risk of relapse either due to scarring or

who have had large surgical moves anteriorly and inferiorly.

3. Stability: The factors that increase stability include:

High quality orthodontic preparation.

Avoiding segmental procedures

Overcorrection where possible.


Alveolar bone grafting.

Bone grafting for inferior repositioning of the maxilla.

Internal rigid fixation for all moves.


THIRD MOLAR CONTROVERSY

JOMFS September 2004 – Clinical controversies

Removal 6-9/12 prior to surgery: Schwartz

Reduce incidence of unfavourable fracture

Better sites for rigid fixation

No sound scientific evidence to prove either way

Based on clinical impression

Removal at time of surgery: Precious

Limits risks

Is cost efficient

Minimises post-surgical consequences

Studies:

Tucker (1995) Unfavourable split 4% BSSO with 8’s, 3 % without 8’s

Mehra (2001) Unfavourable split 3.2% with 8’s, 1.2 % without 8’s

Precious (1998) Unfavourable split 0.94% with 8’s, 2.6 % without 8’s

Not justified to carry out 2 procedures but accepts requirement for judgement, skill

and experience of the surgeon


Early Orthognathic Surgery

Generally, females have about 98% of facial growth complete by age 15 years and males

by the age of approximately 17 years.

Delaying orthognathic surgery until growth is complete or alternatively choosing non-

surgical treatments (e.g. myofunctional therapy, or orthodontic and dental camouflage)

may not always be acceptable options. In some cases, they could be damaging to the

patient’s self-image and adversely affect a child’s social development.

Delaying treatment until adulthood can also potentially exacerbate problems related to

occlusion, mastication, TMJ function and dysfunction, speech and airway.

however, the patient and parents must be made aware that additional surgery may likely

be necessary at a later stage

BSSO is best reserved for patients over the age of 12 years, i.e., after the eruption of the

permanent second molars, so as to avoid damage to these teeth during surgery

Age considerations The ILO and VRO can be performed at virtually any age, since the

design of the osteotomies avoids. The ILO procedure can be used to advance the

mandible or to reposition it backward. When used to advance the mandible, the bone gap

created between the proximal and distal segments requires grafting. However, care must

be taken to avoid damage to developing teeth if any internal rigid fixation is being

applied in the tooth bearing areas.

This surgery should be performed only where mandibular growth is accelerated and

continues beyond the normal expected time of growth cessation. The surgery should not

be performed before maxillary A-P growth is complete since post-surgically, the

mandible will not grow when performed bilaterally and any residual maxillary A-P

growth may cause a Class II relationship to develop.


If earlier surgery is indicated for functional, aesthetic, and psychosocial reasons, the Le

Fort I osteotomy for maxillary advancement must take into consideration some

overcorrection to allow the growing mandible to naturally grow and develop into it. If

this surgery is performed during growth, the patient and parents must be informed that

future surgery will likely be necessary.

Horseshoe maxillary osteotomy (dentoalveolar osteotomy): With this surgical procedure,

the nasal septum and vomer remain attached to the stable palate, and only the

dentoalveolar structures are mobilized. Thus, some A-P maxillary growth may be

expected to occur postoperatively although there are no studies to confirm this.

Surgical Management of Vertical Maxillary Deficiency (VMD)

Pathology

1. The idiopathic deformity:

In the case of idiopathic vertical maxillary deficiency the facial appearance is clinically

recognisable showing a square looking face from the front view, with an overclosed

mandible. There is reduced exposure of the upper incisors, and at rest there is no tooth

show and this may persist even when smiling. The lips may appear squashed and the

mouth wide. The alar base of the nose may be flared and the chin may be prominent with

a deep mentolabial fold. It is therefore vital to assess the quality of the soft tissues

Radiological analysis shows a deficiency of bone between the pyriform aperture and the

apices of the maxillary teeth.


2. Cleft lip and palate

3. Syndromal

Craniosynostosis syndromes e.g. Crouzon, Apert and Pfeiffer, have the genetic problems

driving three dimensional maxillary constrictions around the upper airway.

Binder syndrome affects the part of the midface that develops from the nasal capsule

4. Post-trauma


5. Iatrogenic: A distressing example of overzealous shortening of the ‘long face’ patient

producing a wide mouth, wide nasal alae, and shortened maxilla.

Management of VMD

When there is anterior maxillary vertical deficiency reflected in minimal or absent

maxillary incisal show and a normal upper lip then the maxilla needs to be ‘lengthened’.

However, a decision is needed as to whether, after orthodontic preparation, mandibular

autorotation will produce the aesthetic result, or whether genioplasty needs to be added or

indeed whether the mandible needs to be advanced as well.

With a Class I occlusion the mandible will undergo clockwise rotation and it is likely that

the chin will need to be advanced to give adequate projection of the lower face.

With Class II malocclusion and a deep bite the lengthening of the maxilla will make the

lower facial appearance worse as the mandible rotates downwards and backwards

necessitating the need for a bimaxillary approach.


Rotation of the Maxillomandibular Complex

Atriangle is constructed by connecting ANS, PNS and Pogonion and is called the

maxillomandibular complex triangle. This triangle will assist in predicting and

visualizing the expected hard and soft tissue changes subsequent to surgical

repositioning of the maxilla and the mandible as a complex but independent of the

existing occlusal plane. Rotation of theMMCcan take place in a clockwise or

counterclockwise direction around ANS, Pog or PNS.

However zygomatic buttress (BT) and upper incisor tip or any point along the

lines of the triangle can also be used and is influenced by the aesthetic

requirements of the case (


Orthognathic surgery by almuzian

Health & Medicine

Transcript of Orthognathic surgery by almuzian