Functional genioplasty in growing patients

www.sylvainchamberland.com

Functional Genioplasty in Growing Patients

Edward H. Angle Society

41st Biennal MeetingPasadena

September 25-29, 2015

Langham Hotel

©sylvainchamberland.com

World Tour•Angle East meeting, Paris, April 2014

•AAO, 114th Annual Session, New Orleans, April 2014

•UNC, Chapel Hill, June 2014

•SOBOR, Bruxelles, Jan. 2015

•18èmes JOF, Paris. Nov. 2015

•Alumni University of Montreal, Jan. 2016

©Dr Sylvain Chamberland

Scenario

L.-P.Tr June 94

Baseline

L.-P.Tr Jan 96, RPE HPHG, Intrusive arch

Progress

L.-P.Tr June 97, class I relationship

Final


•Unfavourable vertical growth

•A-P Chin deficiency

•Vertical excess of LAFH

•Lip incompetency

• How many of you would recommend a genioplasty?

• What would happen if you advance the chin in this 13 years old boy?

• What would happen if you do not?


Inferior Border Osteotomy• Isolated procedure or in combination with other maxillo-mandibular osteotomies

✦ Most common for AP deficiency or vertical excess

✓ Simultaneous advancement & vertical reduction

✦ Set back (usually not as successful because of aesthetic problems)

TRAUNER R, and OBWEGESER H. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. II. Operating methods for microgenia and distoclusion. Oral Surg Oral Med Oral Pathol. 1957, Sep;10(9):899-‐909.

Mortise & RF Wire Fixation Rigid Fixation


Functional Genioplasty

• Defined by Precious and Delaire

• Provide beneficial change in the lip function

• Helps to obtain lip competency at repose

Precious DS, Delaire J.Correction of anterior mandibular vertical excess: the functional genioplasty. Oral Surg Oral Med Oral Pathol. 1985 Mar;59(3):229-35.

Proffit WR, Phillips C. Adaptations in lip posture and pressure following orthognathic surgery. Am J Orthod 1988; 93:294-304


Alloplastic Chin Augmentation•Alloplastic material does not integrates with bone

•May drift off the chin

•Muscle and soft tissue ➜ pressure ➜ bone resorption underneath

•Do not permit vertical reduction

•May cause ptosis of the lower lip

•Poor aesthetic and functional outcome


•When ortho treatment has created md incisor protrusion

• Improving relationship between the chin and mandibular incisor (Holdaway ratio)

✦ Might be beneficial to avoid mucogingival problem

✦ Would improve facial profile

•One way to do that

✦ Advance the chin rather than retracting the incisors

CaRo15y4m CaRo17y3m


CaRo15y4m CaRo17y3m


• Helpful when improvement in occlusion was achieved by tooth movement with minimal or unfavourable md growth

K.D. 16y3m 05-04 K.D. 16y9m 12-04 K.D. 18y6m 09-06


Additional benefits• Facial appearance can be a serious psychosocial handicap, even

early in life

• Functional genioplasty

✦ Means to improve facial aesthetics

✦ Function

✦ Stability in conjunction with orthodontic treatmentMcGregor FC. Facial disfigurement, problems and management of social interactions and implications for mental health. Aesthetic Plastic Surg 1990; 14:249-257.


Rationale for the study•Number of publications on genioplasty

✦ Only a few have data for this procedure in adolescents

✦ No good recent data on bone remodeling following genioplasty in growing and non-growing patients

✦ No study include follow-up of a control group who were evaluated as potentially benefiting from genio but rejected it

•Optimum age has been somewhat controversial


Positive Psychosocial Reaction

• To improved facial appearance would suggest earlier treatment for severely affected patient

• Concerns about possible negative effects on growth and decreased stability would be the major reason for waiting until little or no growth remained

McGregor FC. Facial disfigurement, problems and management of social interactions and implications for mental health. Aesthetic Plastic Surg 1990; 14:249-257.

Phillips C, Proffit WR. Psychosocial aspects of dentofacial deformity and its treatment. in Proffit WR, White RP Jr, Sarver DM (eds.), Contemporary Treatment of Dentofacial Deformity. St Louis, Mosby, 2003.

Polido WD, de Clairefont RL, Bell WH. Bone resorption, stability, and soft-tissue changes following large chin advancements. J Oral Maxillofac Surg 1991; 49:251-6.


Osseous Remodeling after Genioplasty

• Martinez et al, JOMS 1999

✦ Better regeneration in the symphysis thickness in patient younger than age 15 than in older non growing individuals

l 75% regeneration of the lingual gap; 92% regeneration of symphysis width

Par. Jo. 12Y 4M 12Y 5M 14Y 4M

Martinez, Turvey & Proffit, Osseous remodeling after inferior border osteotomy for chin augmentation: an indication for early surgery, JOMS 1999, Oct;57(10);1175-80


Impact of genioplasty on mandibular growth during puberty

• Frappier et al, Int. Orthod. 2010 & 2011

✦ Early genioplasty could improve mandibular growth direction

✦ Might increase nasal breathing because of improved lip function

• Weakness:

✦ Sample too small and diverse for broad generalization

✦ No control group + changes pregenio and immediate postgenio not evaluated

Frapier L, Jaussent A, Yachouh J, Goudot P et al. Impact of genioplasty on mandibular growth during puberty, Int. Orthod. 2010, Dec;8(4);342-59Frapier L, Picot M-C, Gonzales J, Massif L et al. Ventilatory disorders and facial growth: benefits of early genioplasty. Int Orthod 2011; 9:20-41


Isolated Genioplasty

•Requires general anesthesia, but not overnight hospitalization

•Day-op procedure

•Usually part of a larger orthognathic surgery plan because medical insurance almost never cover the cost in an isolated procedure

•Medical coverage is provided


Aim of the study

• Clarify the optimal time for functional genioplasty from evaluation of

✦ The pattern of bone remodeling at the chin

✦ The pattern of postsurgical stability in growing and non-growing patients

Methodology


Cephalometric Analysis Time Point

• Experimental Group

✦ T1- 2-3 months prior to genioplasty (10,11± 13,82 weeks)

✦ T2- 1 month post surgery (4,57 ± 3,82 weeks)

✦ T3- 2 years post surgery (111,04 ± 29,91 weeks)

• Control Group

✦ T2- End of orthodontic treatment

✓ Because there was no surgery, there was no T1 equivalent to the experimental group. For consistency in the stats analysis, T2 data are same as T1.

✦ T3- 2 years follow-up (117,42 ± 27,34 weeks after T1)


Sample Characteristics•Patient Sample

✦ Retrospective data (June 92-Dec. 15) from 54 patients who underwent isolated advancement genioplasty to achieve lip competency as an adjunct to orthodontic treatment

✓ Initial sample 59, 5 were excluded (missing rx)

•Control

✦ 23 patients with similar morphology who were offered genioplasty in conjunction with their treatment but declined it

✦ 5 patients of the control group joined the surgery group because they accepted the genioplasty 2 years or more after ortho tx


Sample Characteristics

• Groups are similar relative to % of female

Age

10,00

14,80

19,60

24,40

29,20

34,00

Age

14,31

28,65

16,65

14,00

Group 1 (<15) 32% femaleGroup 2 (15-19) 44% femaleGroup 3 (>19y) 40% femaleGroup 4 Control 39% female

Group N % female

Gr 1 < 15yr 28 32 %

Gr 2 15-19 16 44 %

Gr 3 > 19 10 40 %

Gr 4 Control <15y 23 39 %



• Groups are similar and comparable regarding FMA and symphysis thickness

FMA

25,00

28,40

31,80

35,20

38,60

42,00

FMA

31,97

34,76

32,46

34,06

Group 1 (<15)Group 2 (15-19)Group 3 (>19y)Group 4 Control

Symphysis thickness

0,00

2,30

4,60

6,90

9,20

11,50

Age

8,84

7,998,148,39



•Experimental groups are similar and comparable relative to genial advancement and vertical reduction

•Changes of control growth express horizontal and vertical growth in 2 years (T3T2)

Horizontal changes at Pg

∆Pg Horiz.

-1,00 0,67 2,33 4,00 5,67 7,33 9,00

2,67

5,25

5,88

6,45

Vertical change at Me

-9,20

-6,50

-3,80

-1,10

1,60

4,30

7,00

∆ Me vertical

-4,46

3,833,532,93

Group 1 (<15)Group 2 (15-19)Group 3 (>19y)Group 4 Control


Surgical Procedure•General anesthesia, H. E.-J.

•Technique:

✦ Describe by Precious, Armstrong & Morais

• Anterior and superior repositionning, slide into its new position

• Slice of bone might be removed prn to increase vertical reduction

• Wire osteosynthesis: 3 transosseous double strand 28 gauge SS

✦ (Only 5 had screw fixation, none were removed)Precious DS, Armstrong JE, Morais D. Anatomic placement of fixation devices in genioplasty. Oral Surg Oral Med Oral Path 1992; 73:2-8.


• Dehiscence over the roots secondary to root prominence, lip incompetency and muscular hyperactivity of the chin

• Surgical tips✦ Raise full thickness flap over the roots to fully

expose the buccal plate until the coronal portion of the crest can be seen

✦ Closure of the muscular plane (mentalis muscle) will leave some void filled by blood clot

✦ This will allow bone apposition over the roots down to the advanced genial segment that will remodel (if lip competency has been achieved by the osteotomy design and movement)


Cephalometric Data Magnification calibrated for both scanned argentic film and digital rx

• X-Y cranial base coordinate constructed through sella with the x-axis at SN-7°

• Symphysis thickness measured between ACP-PCP 4 mm below the apex of /1

• Vertical chin height: perpendicular distance from MP to lower incisor tip

• Remodeling above the chin: at B & symphysis thickness increase

• Remodeling in the area of inferior border: ∆ of the notch at posterior limit of osteotomy cut (PGP to MP)


Recommendation for genioplasty• For all subject

• Following Precious & Delaire’s guidelines

✦ Clinical evaluation of the prominence and vertical position of the soft tissue chin relative to the lips and midface


Problems with Strain on Lip Closure•Flattening of anterior surface of the chin due to active contraction of

labiomental muscles to achieve lip closure

•Periosteal tension. Absence of muscular balance

•Alveolar bone thinning ➜ root prominence ➜ gingival recession


Cephalometric Data• A-P chin deficiency

✦ Assessed by /1-APg

• Vertical excess

✦ Assessed by mandibular dental height (male 39,9± 2,7; female 38,9 ± 2,4 mm)

• Most patients had both A-P chin deficiency and excessive mandibular anterior dental height

✦ While a few had primarily A-P chin deficiency or vertical excess.


Cephalometric Data• A-P chin deficiency

✦ Assessed by /1-APg

✓ 72 % of the pre-surgical and control patients had prominence > 1 mm

Baseline : /1-APg (°)Group N Mean S-D RangeGroup 1 (< 15yr) 28 3.01 1.49 0.4 to 5.3Group 2 (15-19) 16 3.67 1.74 -1,2 to 6.5Group 3 (> 19) 10 2.73 1.90 -0.3 to 5.6Group 4 (control) 23 3.18 1.56 1.0 to 5.8


Cephalometric Data•Vertical excess

✦ Assessed by mandibular dental height (male 39,9± 2,7; female 38,9 ± 2,4 mm)

✓ 70 % of pre-surgical and controls patients, this distance was > 43 mm

Baseline : ADHGroup N Mean S-D RangeGroup 1 (< 15yr) 28 44.88 2.67 37.1 to 50,7Group 2 (15-19) 16 45.92 3.27 40.1 to51.1Group 3 (> 19) 10 48.00 4.76 36.9 to 53.1Group 4 (control) 23 43.90 2.39 39.5 to 49.6


Statistical Analysis

• Distribution of the sample was evaluated and judged close enough to normal to use mean, s-d, and range as descriptive statistics

• Design of the study involved comparison between 3 age groups who underwent genioplasty (gr 1, 2, 3) and comparison of the youngest group (gr 1) to an age-matched control group (gr 4) with the same characteristics


Statistical Analysis

• For both comparison

✦ Changes scores between time points were analysed with multivariate ANCOVA, where gender effect was evaluated as a covariate

✦ Although gender did not contribute to the differences, we kept this effect in the model to adjust the conclusion for gender


Statistical Analysis•One-sample T tests

✦ Evaluate the chance that data for each sample point was different from 0

•Pairwise comparisons with Bonferroni adjustments for multiple comparison was use to evaluate the change between time points

✦ Unlike the Tukey adjustment, the Bonferroni method does not need correction because of the unbalanced sample size groups

✦ IBM SPSS Statistics version 21


Method error• 15 cephalograms re-digitized (5 patients X 3 cephs)

✦ 41 variables X 3 time points X 5 patients = 615

✦ Coefficient of fidelity = 0,99968

• Symphysis thickness and PGP

✦ Coefficient of fidelity = 0,92306

• No significant difference between initial and re-digitized tracing

• SAS 9.4 (SAS Institute Inc.)

-150 -100 -50 0 50 100 150

Lecture1

-150

-100

-50

0

50

100

150

Lecture2

Regression

Graphique de la valeur de la deuxième lecture selon la valeur de la première lecture

-10 -5 0 5

Lecture1

-10

-5

0

5

Lecture2

Regression

Graphique de la valeur de la deuxième lecture selon la valeur de la première lecture

Results


Change at Surgery

• Typical change afterfunctional genioplasty

• Isn't this a nicer outcome?

• What would be the long-term benefit from 14y 7m to adulthood?


•Typical change afterfunctional genioplasty

Change at SurgeryFollow-up 2 y

LPTr 160800

Follow-up 15 y

LPTr 030713


13y4m 14y7m

~ 2 month post genio

~ Follow up 2 years ~ Follow up 15 years

pre genio


Change at Surgery

• The changes were highly significant (< .0001)

•No significant differences between the 3 groups

•Mean advancement 6,1 ± 2,2 mm; vertical reduction 3,3 ± 2,5 mm

Horizontal Change at Pg

Gr 1 (<15 y)

Gr 2 (15-19 y)

Gr 3 (>19 y)

0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0

5,25

5,88

6,45

Gr 1 (<15 y) Gr 2 (15-19 y) Gr 3 (>19 y)

Vertical Change at Me

(mm

)

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

Gr 1 (<15 y) Gr 2 (15-19 y) Gr 3 (>19 y)

3,833,532,93


Symphysis Thickness Changes•Significant increase for the 3 groups

•Slight but significant decrease for Controls

•T1-T3

✦ Gr 1 = 3,44 ± 2,51 (p < .001)

✦ Gr 2 = 2,15 ± 1,88 (p < .001)

✦ Gr 3 = 1,04 ± 1, 16 (p = .027)

✦ Gr 4 = -0,44 ± 0,67 (p = .004)

•Pairwise comparison (bonf. adjust.) Gr 1 ≠ Gr 3 (p =.024) (Gr 2 ≠ Gr 1 or Gr3)

1,29

1,11

2,4

T3T2

T3T1

-2,0 -1,0 0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0

-0,44

-0,44

1,04

1,11

2,15

2,06

3,44

3,24

Gr 1 (<15)Gr 2 (15-19)Gr 3 (>19y)Gr 4 (Controls)


•Youngest group

✦ 39%: ≥2 to <4 mm increase

✦ 28%: ≥4 mm increase

✦ ≥2 to ≥4: Gr 1 ≠ Gr 3 (p=.011)

•Gr 2


•Gr 3


✦No patients > 4 mm change

•Gr 4 Controls:

✦ 30% = > -1 mm decrease (and 39% = -1 to 0)

better remodeling

Two-thirds {


Pg Change in Coordinate Position•Combination of growth and surface

remodeling at or near the chin

•T2-T3

✦ Significant change from 0

✓ Gr 1 & Gr 4

✦ But change Gr 1 ≠ Gr 4

✦ Non Sig. for Gr 2 & Gr 3


Me Change in Coordinate Position•Combination of growth and surface remodeling

at or near the chin

•T2-T3

✦ Vertical growth of Gr 1 similar to Gr 4


✓ Gr 1, Gr 2, Gr 4 (Controls)

✦ Non Sig. change for Gr 3


Vertical dentoalveolar Change in Coordinate Position

•T2-T3


✓ Gr 1, Gr 2, Gr 3, Gr 4

✦ Change of Gr 1 ≠ Gr 2, Gr 3 & Gr 4

•Vertical change at Me was balanced by posterior facial growth

✦ FMA change is non Sig. for any Gr


Pairwise Comparison Between Groups

•Confirms significant differencein symphysis thickness change Gr 1 (<15y) vs G3 (>19 y)

•Confirms that remodeling in Gr 1 (<15y) is different from remodeling in Gr 3 (>19 y)and Gr 4 (controls)


What could explain bone remodeling?

•Is it:

✦ The amount of genial advancement?

✦ The vertical dentoalveolar growth?

✦ The total face height growth?

✦ The Age at surgery?


★But R2 is low (7%, 10% and 16%)

• Amount of genial advancement (T1-T2). r = 0.264; p = .028

• Vertical dentoalveolar growth (∆ADH). r = 0.316; p = .011

• Age at surgery. r = -0.396; p = 0.002

Correlations•3 Variables significantly correlated to postsurgical change in

symphysis thickness (outcome at T3)


Regression: Dependent variable: Symphysis thickness

•If the predictor variable change of 1 standard deviation, the dependent variable increase of the Coefficient Beta (s.-d.)

• Ranking the predictor variable

✦ Genial advancement (∆Pg horiz) St. co. ß = 0,264; p= 0.057

✦ Vertical dentoalveolar growth (∆ ADH) St. co. ß = 0,272; p= 0.049

✦Age at surgery St. co. ß = -0,332; p= 0.032

✦ The younger the age at surgery and the better the dentoalveolar growth, the more the symphysis will increase in thickness due to bone apposition

Genial advancement =

Not a determinant


Remodeling Changes of the Notch

• Remodeling of the symphysis involves

✦ Bone apposition above the repositioned chin

✓With changes leading up to and beyond B point

✓ Removal of bone adjacent to the notch in the lower border


Remodeling Changes of the Notch

• T2-T3

✦ Significant change for Gr 1 & Gr 2

✓ Reduction of the notch 1,17 & 0,62 mm respectively

✦ Non Sig. change for Adult (Gr 3) & Controls


Typical Remodeling Pattern Young Patients

• Greatest symphysis thickness increase (3,24 ± 2,68 mm (p = .000))

• Greatest remodeling at the notch (1,17 ± 1,29 (p =.000)) & bone apposition at B (1,06 ± 1,33 mm (p = .000))


Correlation: Dependent variable: PGP_MP at T3

• ∆ ADH_change T3T2 r = 0.311; p = 0.012

• ∆ PGP_change T3T2 r = 0.322; p = 0.009

• Age at surgery r = -0.331; p = 0.008

★ Significantly correlated to the outcome of inferior border remodeling at T3★ But R2 is low (~10%)


Regression: Dependent variable: PGP_MP at T3

•Predictor variable

✦Dentoalveolar growth change (∆ ADH) St. co. ß = 0,272; p= 0.049

• Change of 1 standard deviation of the dentoalveolar growth will change the dependent variable of 0.272 standard deviation.

✦ The greater the dentoalveolar growth, the more the notch on the inferior border will be remodelled

✦ Neither the amount of genial advancement (∆Pg) nor the age at surgery were significant predictors of the outcome

✦ The decreased incisors eruption after genioplasty in older adolescent and adults is the primary reason for better remodeling in young patients


Therefore

• The age at genioplasty, which affects the amount of incisor eruption afterward, does make a difference in the extent of both bone apposition and remodeling

• More apposition and remodeling in patients under age 15, less in late adolescents and still less in adults


Stability of the Surgical Repositioning•Postsurgical changes are due to

✦ Combination of mandibular growth & surface remodeling near the chin

•Gr 1 vs Gr control

✦ Mean AP change after genio of Gr 1 is less than Controls (i.e. slightly more stable) but the difference is small and non sig. (p = 0,09)

✦ Vertical change is similar Gr 1 vs Controls


Therefore

• Forward and downward growth at the chin was not significantly affected by genioplasty

• Changes in chin position were maintained in growing patients

Discussion


Data from this study shows

• Amount of new bone formation after genioplasty

• Extent of remodeling around the repositioned chin

✦ Greater in patients still in mid-adolescence than in late adolescents and adults

♀ 14y6m

♂ 31y8m

♀ 16y3m


♂HuPi 17y 2m T3 Sept 2005♂HuPi 14y 7m postgenio T2 Feb 2003

Data from this study• Confirm and extend reports by Martinez et al (JOMS1999)

✦ Better healing in patients younger than age 15


Remodeling•Our study support other findings

✦Bone remodeling at the inferior border of the proximal segment between the distal point of the osteotomy cut and the advanced distal segment

✦Gr 1 and Gr 2:

✓ Significant reduction of this notch (1,2 ± 1,3 mm; 0,6 ± 0,9 mm)

✦Gr 3:

✓Modest non-significant reduction (0,3 ± 1,0 mm)Polido WD, de Clairefont RL, Bell WH. Bone resorption, stability, and soft-tissue changes following large chin advancements. J Oral Maxillofac Surg 1991; 49:251-6Davis WH, Davis CL, Daly BW, Taylor C. Long-term bony and soft tissue stability following advancement genioplasty. J Oral Maxillofac Surg 1988; 46:731-5.Tulasne JF. The overlapping bone flap genioplasty. J Craniomaxillofac Surg 1987; 15:214-21.Precious DS, Cardoso AB, Cardoso MC, Doucet JC. Cost comparison of genioplasty: when indicated, wire osteosynthesis is more cost effective than plate and screw fixation. Oral Maxillofac Surg 2013, posted on web site Nov 23.Park HS, Ellis E, Fonseca RJ, Reynolds ST, Mayo KH. A retrospective study of advancement genioplasty. Oral Surg Oral Med Oral Path 1989; 67:481-9.Polido WD, Bell WH. Long-term osseous and soft tissue changes after large chin advancements. J Craniomaxillofac Surg 1993; 21:54-9.


Growth

•Control group has significant resorption at B point (0,4 ± 0,6 mm; p = .007)

✦ Symphysis thickness decrease (0,44 ± 0,67 mm; p = .004)

•Consistent with the usual pattern of growth

✦ Chin more prominent by resorption above Pg extending upward toward + above B point

Marshall SD, Low LE, Holton NE, Franciscus RG et al. Chin development as a result of differential jaw growth. Am J Orthod Dentofac Orthop 2011; 139:456-64

Our dataB →

Gr 1: 1,06 ± 1,33Gr 2: 0,85 ± 1,14Gr 3: 0,69 ± 1,00

Gr Control← B

Gr C: -0,36 ± 0,58


Remodeling

•All 3 age group had similar bone apposition at B point (0,7 to 1,0 mm)

✦ Like Park et al 1989, Shaughnessy et al 2006, Precious et al 1992 & 2013

•Bony angles above repositioned chin became rounded, rough edge became smooth.


Remodeling• Shaughnessy et al suggested that autogenous bone grafts from the

iliac crest placed above the repositioned distal segment were responsible for the improved contours

• None of our patients received a graft

• All had significant bone apposition at B point

• Bone grafting is questionable particularly form a donor site like iliac crest that requires invasive surgery

Shaughnessy S, Mobarak KA, Hogevold HE, Espeland L. Long-term skeletal and soft-tissue responses after advancement genioplasty. Am J Orthod Dentofac Orthop 2006; 130:8-17.

AJODO 2006; 130:8-17


Skeletal vs Chronological Age•Would it make a difference?

✦ Recent review of methods to establish peak growth at adolescence concluded that chronological age is better (Mellion et al, AJODO 2013)

✓ Group younger than 15 years might had some relatively mature girls

✓ Age-15-19 group might had some relatively immature boys

✦ That would have minimized rather than augmented the differences observed

Mellion ZJ, Behrents RG, Johnston LE. The pattern of facial skeletal growth and its relationship to various common indexes of maturation. Am J Orthod Dentofacial Orthop 2013;143:845–854.


Remodeling• Increased remodeling of the facial alveolar bone above osteotomy

site

✦ Bone apposition at B point (0,7 to 1,0 mm)

✓ Permits better bone support for the lower incisors

‣ May help preventing mucogingival problems buccal to lower incisors or bone dehiscence

‣ This help to explain the thickening of the symphysis thickness during follow up


Follow-up 2 years

AML030806AML240304

End of ortho

AML030314

Follow-up 10 years

Post Genio

LPTr210998

Follow-up 2 years

LPTr160800

End of ortho

LPTr060697

Follow-up 15 years

LPTr160513

Control

Gr 1 (< 15y)


Growth•No evidence support a negative effect on mandibular growth from

genioplasty

✦ Whether done early or late adolescence

•FMA decrease during normal growth

✦ Same as in younger genioplasty patients and controls

•Once lower canines are erupted (~ 12-13 y)

✦ No problem to do a genioplasty


•Change, or lack of it, in typical control patient

• Lip incompetency persist, facial convexity persist, bone resorption occurs at B, symphysis thickness decrease


•Change, or lack of it, in typical control patient

• Lip incompetency persist, facial convexity persist, bone resorption occurs at B, symphysis thickness decrease

AML030314

Follow-up 10 years


Stability•Previous study reported that genioplasty is the most stable orthognathic

surgery procedure

✦ Tulasne, using different surgical procedure, reported greater relapse (40%) in younger patient

✦ Martinez et al reported greater relapse (16%) but not clinically nor statistically sig.

Davis WH, Davis CL, Daly BW, Taylor C. Long-term bony and soft tissue stability following advancement genioplasty. J Oral Maxillofac Surg 1988; 46:731-5.

Shaughnessy S, Mobarak KA, Hogevold HE, Espeland L. Long-term skeletal and soft-tissue responses after advancement genioplasty. Am J Orthod Dentofac Orthop 2006; 130:8-17.

Erbe C, Mulié RM, Ruf S. Advancement genioplasty in Class I patients: predictability and stability of facial profile changes. Int J Oral Maxillofac Surg 2011; 40:1258-62.

Tulasne JF. The overlapping bone flap genioplasty. J Craniomaxillofac Surg 1987; 15:214-21

Martinez JT, Turvey TA, Proffit WR. Osseous remodeling after inferior border osteotomy for chin augmentation: an indication for early surgery. J Oral Maxillofac Surg 1999; 57:1175-80, discussion 1181.


Stability• Relapse at Pg can be estimated by Pg to N perp-FH

✓Gr 1: -0,48 mm (7%)

✓Gr 2: -0,86 mm (14,7%)

✓Gr 3: -0,24 mm (4,7%)

✦ Relapse T2T3 is not significant for any group (p > .235 Anova Gr * Time)

✦ Relapse is similar between group, (p > .176 Anova Time * Gr)


Stability

• Our findings do not support greater relapse at Pg for younger growing patients

• 91% had wire fixation

• Better post-surgical stability with more costly bone screws and plates may not be a consideration

Precious DS, Cardoso AB, Cardoso MC, Doucet JC. Cost comparison of genioplasty: when indicated, wire osteosynthesis is more cost effective than plate and screw fixation. Oral

Maxillofac Surg 2013, posted on web site Nov 23.


Why I don't like rigid fixation for a genioplasty

Poor contact between distal & proximal segment

Screw EmbedLu.Mo.010710 Lu.Mo.130212

Bone formation over superior portion of fixation device and resorption in area of inferior

portion of fixation device

Resorptive zone

Apposition zone

Externalization of the fixation

Poor remodeling between distal & proximal segment

540$ Can


Externalization of fixation device• Resorption of the buccal surface

of the distal fragment

• Source of discomfort

Precious, D. S, Cardoso A.B., Cardoso M.C.A.C., Doucet J-C. "Cost Comparison of Genioplasty: When Indicated, Wire Osteosynthesis Is More Cost Effective Than Plate and Screw Fixation." Oral Maxillofac Surg 18, no. 4 (2013): doi:10.1007/s10006-013-0437-y


Courtesy Dr Dany Morais

Why do I prefer osteosynthesis?

Resorptive zone

De.Le060608De.Le130410

Resorptive zone (R)

Apposition zone (A)

Improved contact between proximal and distal segment

Precious D., Armstrong J., Morais D., Anatomic placement of fixation device in genioplasty, OOO 1992,; 73-2-8Precious, D. S, Cardoso A.B., Cardoso M.C.A.C., Doucet J-C. "Cost Comparison of Genioplasty: When Indicated, Wire Osteosynthesis Is More Cost Effective Than Plate and Screw Fixation." Oral Maxillofac Surg 18, no. 4 (2013): doi:10.1007/s10006-013-0437-y

Complete coverage of fixation wires by bone and smooth labial cortical

bone of anterior mandible

5$ Can


• On average old adolescent

✦ Significant ∆ Symphysis thickness: 2,06 ± 1,24 (p = .000)

✦ Significant bone apposition at B

✓ ∆ B horizontal: 2,13 ± 1,92 mm (p = .000)

✓ ∆ BPg to MP: 0,85 ± 1,14 mm (p = .009)

✦ Significant remodeling of the notch on the inferior border

✓ ∆PGP to MP: 0,62 ± 0,88 mm (p = .013)

♂GaBo T1 July 08 17y 1m♂GaBo T2 August 08 17y 2m

♂GaBo T2 August 10 19y 2m


•On average adults shows,

✦ Significant increase of symphysis thickness: 1,11 ± 1,02 mm (p = .011)

✦ Small, but n.s. bone apposition at B

✓ ∆ B horizontal: 1,9 ± 1,42 mm (p = .004)

✓ ∆ BPg to MP: 0,69 ± 1,00 mm (n.s)

✦ A few if any bone remodeling at the inferior border

✓ ∆PGP to MP: 0,30 ± 1,00 mm (n.s.)

Conclusion


Benefits of Functional Genoplasty

• Increased symphysis thickness

• Bone apposition at B point

• Remodeling at the inferior border

• Better bone apposition and remodeling is observed in younger patients than adults


Benefits of Functional Genioplasty

• Improved facial proportions

• Improved smile aesthetics and display of the incisors

• Lip competency in function and repose

• Decrease muscular periosteal tension above the chin and bone apposition at B point


• Genial advancement and vertical reduction move up the lower lip along with the chin eliminating the display of the lower teeth when smiling

Initial Follow up 2 y in retention

Proffit, William R., and Raymond P. White, Jr. "Combined Surgical-orthodontic Treatment: How Did It Evolve and What Are the Best Practices Now?" AJODO 147, no. 5 (2015): doi:10.1016/j.ajodo.2015.02.009.


Functional Genioplasty• When indications for such a genioplasty are recognized

✦ Early surgical correction (< age 15)) produces a better outcome in terms of bone remodeling

✦ This is related to greater vertical growth of the dentoalveolar process in younger patients

✦ There is no difference in post-surgical stability in younger and older patients


Further study

• Soft tissue changes relative to hard tissue changes

• Long term change and stability. ✦ Patients are currently recalled and we have 24 patients at T4 (4 to 10

years post genio) so far.


Stability / Lower Incisors

• Unpaired T Test

✦ FMIA change n.s. for any groups

• Unvariate ANOVA

✦ No sig. diff. between any groups

• Therefore, we cannot conclude that incisors stability benefits from genioplasty

0,80$1,04$

0,72$

)0,61$

)4,50$)4,00$)3,50$)3,00$)2,50$)2,00$)1,50$)1,00$)0,50$0,00$0,50$1,00$1,50$2,00$2,50$3,00$3,50$4,00$4,50$5,00$

Mean%

∆FMIA%T2,T3%

Group$1$(<$15$y)$Group$2$(15)19)$Group$3(>19)$Group$4$(Control)$

Tendency to proclination in Gr 4


Surgical Tx planning

/1-APg

Md1-APO(mm) 1.5 1.0ADH_Md1MP(mm)44.6 39.9N-A-Pg (°) 6.4 4.5

Md1-APO(mm) 4.3 1.0ADH_Md1MP(mm)49.5 39.9N-A-Pg(°) 13.3 4.5

/1-APg

Md1-APO(mm) 1.7 1.0ADH_Md1MP(mm)42.5 39.9N-A-Pg(°) 4.8 4.5

OutcomeVTOPre surgery


Clinical Soft Tissue Evaluation

Lip incompetency at repose

Pinching the mentalis muscle brings the

lips together


Clinical Soft Tissue Evaluation

Mentalis

Vertical excess

}} } Vertical

excess


• How many cases have you finished with such a profile?

• Isn’t this a better outcome?

MaLa 13 y Sept.10 MaLa 13 y 4 m January 11


• And the benefit long-term?

MaLa 13 y Sept.10 MaLa 13 y 4 m January 11 MaLa 15 y 5 m Feb. 13


• Class I occlusion achieved

• Lip strain persist

• Chin projection deficient

• LFH slightly excessive

♂HuPi 12y 4m pre-ortho ♂HuPi 14y 6m postortho T1 Feb 2003

Lip incompetency


• Genioplasty

• 29 days post surgery

• Lip competency achieved

♂HuPi 14y 7m postgenio T2 Feb 2003

29 days post surgery

♂HuPi 14y 6m postortho T1 Feb 2003

Lip incompetency


• Profile benefits from genioplasty

• Significant bone remodeling at and near the chin

♂HuPi 14y 7m postgenio T2 Feb 2003

29 days post surgery

♂HuPi 14y 6m postortho T1 Feb 2003

Lip incompetency

♂HuPi 17y 2m T3 Sept 2005

30 months into retention

Lip competency


KiLe250511 11y8m KiLe160913 14y KiLe091213 14y2m


CaLe280313 Ti

16y 2m T1

CaLe220413 T2

16y 3m T1

CaLe211113 Follow up 7 months

16y 9m Prog 7 months


h

MC Si 07-91 16y 7m MC Si 04-93 18y 5m MC Si 08-93 18y 8m MC Si 04-95 20y 4m


• Young adult

✦ Bone apposition at B

✦ Good bone remodeling at the inferior border

SéRh 04-99 22y 9m 09-99 23y 2m 09-01 25y 1m

01-07 30y 6m

Follow up 7 years post genio


♀KaBo Feb 02 initial

♀31y 7m Feb 02 initial

♀KaBo Feb 04 Progress

♀33y 7m Feb 04 PreGenio

• Class I

• Bimaxillary protrusion

• Lip incompetency


♀KaBo Feb 02 initial

♀31y 7m Feb 02 initial



• 3 months post genio

• Improved facial aesthetics&Lip competencyat repose

3 months postgenio

1 month postgenio

3 months postgenio



♀33y 7m Feb 04 PreGenio 3 months postgenio

1 month postgenio

3 months postgenio

KaBo June 06 2y post genio

• Follow up 2 y

• Some bone apposition at B point

• Inferior border notch remain


3 months postgenio

1 month postgenio

3 months postgenio



• Follow up 7 y

• Benefits from genioplasty are obvious

• Notch on the inferior border remain

KaBo May 13 7y post genio


• What would happen if you recommend a genioplasty to achieve lip competency?

GeAu 29y 4 m May 08 GeAu May10


• Advancement and vertical reduction help to achieve

✦ Lip competency at repose

GeAu 29y 4 m May 08 GeAu May10 GeAu June10


• Bone apposition occurred

• Overbite improved

• Improved smile display

• She's happy!

GeAu 29y 4 m May 08GeAu May10 GeAu June10


GeAu Jan13


• Genial advancement and vertical reduction move up the lower lip along with the chin eliminating the display of the lower teeth when smiling


Proffit, William R., and Raymond P. White, Jr. "Combined Surgical-orthodontic Treatment: How Did It Evolve and What Are the Best Practices Now?" AJODO 147, no. 5 (2015): doi:10.1016/j.ajodo.2015.02.009.

Thank you

Dr William Proffit

my son Pier-Eric Chamberland

www.slideshare.net/sylvainchamberlandwww.sylvainchamberland.com

A special thank you to

and my wife Carole for her support

Merci, Dr Proffit

Thank you

Dr William Proffit

my son Pier-Eric Chamberland

www.slideshare.net/sylvainchamberlandwww.sylvainchamberland.com

A special thank you to

and my wife Carole for her support

Functional genioplasty in growing patients

Health & Medicine

Transcript of Functional genioplasty in growing patients