Mandibular Distraction for Micrognathia in Neonates · 2019-06-15 · quires mandibular osteotomies...

Mandibular Distraction for Micrognathiain Neonates

Carrie E. Zimmerman, BS,* Laura S. Humphries, MD,* Tulsi Roy, MD,* Russell R. Reid, MD, PhD*

*Department of Surgery, Section of Plastic Surgery, University of Chicago Medical Center, Chicago, IL

Education Gaps

1. Pierre Robin sequence (PRS) comprises the clinical triad of micrognathia,

glossoptosis, and upper airway obstruction. The severity of micrognathia

and airway obstruction among neonates with PRS varies. The evaluation of

neonates with micrognathia is not standardized across neonatal units,

which may result in delayed referral to and, therefore, delayed evaluation

and care by appropriate specialists.

2. Airway management for neonates with PRS ranges from noninvasive airway

support to surgical intervention for mandibular lengthening. The gold

standard surgical intervention is mandibular distraction osteogenesis (MDO),

the goal of which is to anteriorly reposition the mandible and tongue base

away from the posterior pharynx to relieve upper airway obstruction. The

ideal anatomic endpoint of mandibular distraction is not yet known.

3. Surgical intervention for treatment of upper airway obstruction in patients

with PRS carries a risk of complications and long-term effects. With the

introduction of MDO for PRS less than 2 decades ago, long-term clinical

outcomes data with MDO are currently lacking.

Abstract

Pierre Robin sequence (PRS) comprises the clinical triad of micrognathia,

glossoptosis, and upper airway obstruction, with a reported incidence of 0.5

to 2.1 per 10,000 live births. The mainstay of management involves prompt

diagnosis of airway obstruction and airway management. The gold standard

surgical intervention for management of symptomatic micrognathia is

mandibular lengthening by distraction osteogenesis (MDO) to anteriorly

reposition a retroflexed tongue and relieve obstruction. Although MDO is

often successful in the short-term in relieving upper airway obstruction and/

or avoiding the need for permanent tracheostomy, the long-term effects of

MDO are not yet elucidated.

Objectives After completing this article, readers should be able to:

1. Describe the initial diagnostic evaluation, airway analysis and evaluation,

and necessary referrals for neonates with Pierre Robin sequence.

AUTHOR DISCLOSURE Ms Zimmerman, DrsHumphries, Roy, and Reid have disclosed nofinancial relationships relevant to this article.Dr Reid has disclosed receipt of lab royaltiesfrom Applied Biologicals, Inc., from sales of ICAL cells. This commentary does not contain adiscussion of an unapproved/investigativeuse of a commercial product/device.

ABBREVIATIONS

HRQOL health-related quality of life

MDO mandibular distraction

osteogenesis

PEBP pre-epiglottic baton plate

PRS Pierre Robin sequence

PSG polysomnography

TLA tongue-lip adhesion

UAO upper airway obstruction

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2. Describe the indications for and technical aspects of mandibular

distraction osteogenesis (MDO), along with its complications.

3. Recognize the importance of appropriate patient selection for MDO.

4. Recognize the psychological and quality-of-life implications of MDO.

5. Identify treatment alternatives to MDO.

INTRODUCTION

Micrognathia is defined as a developmentally small man-

dible withmarkedly posterior positioning of themandibular

alveolus relative to the maxillary alveolus. (1) Micrognathia

has an incidence of 1 in 1,000 births. (2) This condition

presents with a broad clinical range of severity, from asymp-

tomatic presentation to severe upper airway obstruction

(UAO), the treatment of which involves airway stabilization

with or without surgical intervention to lengthen the man-

dible (Fig 1).

Pierre Robin sequence (PRS) includes the clinical triad

of micrognathia, glossoptosis (ie, posterior displacement

of the tongue), and UAO. Though not typically described

as part of the triad, cleft palate is frequently associated

with PRS, which can compound difficulties with feeding

and speech both in the short- and long-term. Microgna-

thia can be diagnosed with imaging during the prenatal

period, while the PRS triad is identified at birth. (3)(4) The

prevalence of PRS has been cited as being between

0.5 and 2.1 per 10,000 live births, with the highest

incidence among whites and the lowest incidence among

non-Hispanic African Americans. (5) Tongue base pro-

lapse and UAO in PRS may result in feeding difficulty,

failure to thrive, brain damage, and sudden death. (1)(3)

(6)(7) Mortality in PRS has been cited to range between

2.2% and 26%, most commonly because of obstructive

apnea and cardiac failure as a result of severe airway

obstruction. (8)

Furthermore, patients with PRSmay be classified into

“syndromic” or “isolated” groups. Patients with “syn-

dromic PRS” have a concomitant syndrome or anatomic

abnormalities. Syndromic PRS occurs in 45% to 80% of

cases (Table 1). Patients with “isolated PRS” do not have

other associated abnormalities. (3)(6)(8) Because of the

frequent association with multilevel airway obstruction

in syndromic PRS, achieving and maintaining an un-

obstructed airway in children with syndromic PRS tends

to be more difficult than in children with isolated

PRS. (3)

EVALUATION AND MANAGEMENT OF PRS

A systematic approach to the clinical evaluation and treat-

ment of neonates with micrognathia is essential to provide

comprehensive care (Fig 2). Asymptomatic micrognathia

may require multidisciplinary input, but often, outpatient

referral and follow-up are adequate. Alternatively, in a

symptomatic patient with micrognathia and UAO, initial

stabilization of the airway is an essential first step. Following

stabilization, patients with micrognathia should undergo

further evaluation to first establish whether the microgna-

thia is isolated or part of a syndrome. Patients identified as

having PRS should undergo an extensive multidisciplinary

evaluation that may include neonatology/pediatrics, sleep

medicine, otolaryngology, plastic surgery, genetics, speech

pathology, and nutrition services.

The primary objective of PRS treatment is securing a

safe airway to improve oxygenation, and consequently

improve feeding, speech, and developmental outcomes.

Airway evaluation and stabilization should begin promptlyFigure 1. Decision tree for evaluation and management of infants withmicrognathia.

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TABLE 1. Common Syndromes Associated with Pierre Robin Sequence

SYNDROME INCIDENCE ANATOMIC CHARACTERISTICS PHYSIOLOGIC CHARACTERISTICS

Velocardiofacialsyndrome

1:4,000 live births Found in most patients with DiGeorge sequenceand conotruncal anomaly face syndrome.

Speech abnormalities (hypernasal)

Includes:• Breathing difficulty

Craniofacial anomalies

• Chronic otitis media

• Retrognathia

• Transient neonatal hypocalcemia

• Long face with prominent nose

• Mild intellectual impairment

• Velopharyngeal weakness

• Psychiatric disorders

• Submucous or overt cleftsCardiovascular anomalies• Congenital heart defects• Carotid artery anomalies

Craniofacial orhemifacialmicrosomia(39)(40)

1:4,000–5,500 livebirths

A variable presentation including: • Hearing impairmentCraniofacial anomalies • Airway compromise• Mandibular hypoplasia• Microtia• Orbital distortion• Hypoplasia of facial muscles, parotid gland,and muscles of mastication

Cardiac anomalies• Septal and outflow tract heart defectsGoldenhar syndrome is within the spectrum of

this disorder. Additional characteristics includeepibulbar dermoids and vertebral defects

Stickler (41)(42)and Marshallsyndromes (43)(44)

1:7,500–9,000(Stickler)

Overlapping connective tissue disorders with: • Airway compromiseCraniofacial anomalies • Sensorineural deafness• Flat midface with depressed nasal bridge,short nose, anteverted nares

• Myopia

• Micrognathia• May have soft palate cleftEye anomalies• Abnormal vitreous gel in eye• Retinal detachment (Stickler)• CataractsMusculoskeletal anomalies• Joint hypermobility• Arthritis• Osteoarthritis in 3rd or 4th decade• Spinal abnormalities• Spondyloepiphyseal abnormalities (Marshall)• Anhidrotic ectodermal dysplasia (Marshall)Cardiac anomalies• Mitral valve prolapse (Stickler)

Treacher-Collinssyndrome (45)

1:25,000–50,000live births

Variable presentation but always bilateral. • Conductive hearing lossIncludes: • Airway difficulty and respiratory

compromise• Malar and mandibular hypoplasia• Speech and feeding difficulty• Zygomal cleft

• Antimongoloid slanted eyes with eyelid notch(colobomas)

• Retrusive jaw and chin• External ear abnormalities• Absence of eyelashes in medial third oflower eyelid

• Cleft lip and choanal atresia may be present

Continued



after a diagnosis of PRS, beginning with conservative and

noninvasive measures such as continuous pulse oximetry

monitoring and prone or side positioning. Approximately 70%

of patients can be stabilizedwith positioning changes alone. (8)

(9) If repositioning does not adequately relieve obstruction,

nasopharyngeal airway placementmay be temporarily used for

up to 2 to 4 months. Patients may also be treated with non-

invasive continuous positive airway pressure therapy; however,

large cohort data for its long-term effectiveness among patients

with PRS are lacking. (10) Patients who fail less invasive

airway support may require endotracheal intubation or even

tracheostomy placement. If advanced airway support is

required, or if patients demonstrate significant obstruction

during oral feedings, nasogastric tube feedings may be nec-

essary for nutrition.Genetic evaluation andneonatal screening

in patients with PRSmay identify the presence of concurrent

congenital anomalies and syndromes (Table 1). A geneticist

can help guide further evaluation. If more anomalies are

identified, the infant may require additional evaluation by

subspecialists (eg, neurology, cardiology, ophthalmology).

Polysomnography (PSG), or a “sleep study,” determines

the presence and severity of UAO and may identify

TABLE 1. (Continued)

SYNDROME INCIDENCE ANATOMIC CHARACTERISTICS PHYSIOLOGIC CHARACTERISTICS

Nagar syndrome(acrofacialdystosis)(46)

Rare Similar characteristics to Treacher-Collinssyndrome, with noted differences

• Hearing impairment

• Absence of colobomas• Secondary speech and language delays

• Severe, wide cleft palate seen in all cases• Respiratory and feeding difficulty

• Limb anomalies including hypoplasiaof thumbs, radius, metacarpals

• Short stature

Figure 2. University of Chicago Hospital clinical evaluation and management guidelines for patients with Pierre Robin sequence (PRS). BMP¼basicmetabolic panel; CBC¼complete blood cell count; ECHO¼echocardiography.



concomitant central apnea by monitoring for specific respi-

ratory events, including apneic and hypopneic events, and

oxygen desaturations. The 2012 American Academy of

Sleep Medicine guidelines delineate obstructive severity

with an apnea-hypopnea index and with the lowest associ-

ated oxygen saturation (Table 2). (10)(11)(12)(13) Serial cap-

illary blood gases with increasing carbon dioxide levels,

respiratory acidosis with metabolic compensation, and oxy-

gen desaturations at rest and during feedings can all support

the diagnosis of chronic airway obstruction. (1)(3)(13)

Nasopharyngeal endoscopy should be routinely per-

formed to identify concomitant upper airway pathology,

including subglottic airway obstruction, which may occur

in up to 23% of patients with PRS. (14) The identification of

additional airway pathology is important, because its pres-

ence may influence the definitive management of PRS. (14)

Combining PSG and nasopharyngeal endoscopy results

is useful to identify suitable candidates for mandibular

distraction osteogenesis (MDO). Although the presence

of central sleep apnea and/or concomitant airway pathology

does not preclude the use of MDO to address UAO, patients

may continue to have airway, breathing, and oxygenation

problems given their comorbidities. Thus, patients with

evidence of UAO on PSG with few or no central sleep

apneas, along with absence of concomitant airway pathology

may benefit the most from MDO.

SURGICAL MANAGEMENT OF PRS

Mandibular Distraction OsteogenesisAlthough conservative noninvasive measures are typically

effective to relieve airway obstruction, 23% of patients with

PRS will require surgical intervention. (3)(8)(9) MDO has

become the preferred surgical option at many institutions

for neonates and infants with PRS-associated UAO who

would otherwise require tracheostomy. (7)(15) MDO re-

quires mandibular osteotomies and placement of distrac-

tors that allow for gradual lengthening of the mandible in

an anterior-posterior direction. Anterior advancement of the

mandible promotes anterior repositioning of the tongue

relative to the oropharynx, with the goal of relieving tongue-

based airway obstruction. McCarthy et al published the first

clinical report ofmandibular distraction with a rigid external

distractor device for congenital mandibular deformities in

1992. (16) Since that time, both resorbable and nonresorb-

able internal distractor devices have been developed and are

commercially available. (8)

The MDO process is invasive and the treatment regimen

is intensive, spanning several weeks. The treatment involves

an initial surgery to place the device, followed by a 3-phase

distraction period. Figure 3 displays the authors’ institu-

tional timeline and protocol for the use ofMDO in neonates.

For neonates, the distraction period includes: 1) a latency

phase, which is the 24-hour period after distractor place-

ment and the start of distraction; 2) a distraction phase,

wherein the anterior mandible segment is advanced a

specific distance per day (typically 1 mm/day in a 0.5-mm

twice-daily regimen), which may last up to 2 to 3 weeks

depending on the rate of distraction and goal distraction

length; and 3) a consolidation phase, a period ranging from

6 to 8 weeks after distraction completion to allow for bone

healing. The devices are removed after the consolidation

phase. (17)(18)(19)

At the authors’ institution, PSG guides the endpoint of

mandibular distraction. After the distraction phase of

MDO is completed, PSG is performed to confirm reso-

lution of the UAO. (20) The appropriate anatomic end-

point of mandibular distraction beyond the relief of UAO

is unknown. While some advocate for overdistraction or

“overcorrection” of the mandible, this practice may result

in a severe underbite or class III malocclusion and have a

long-term impact on maxillary-mandibular relationships.

Recently, the concept of using airway volume and mor-

phology to guide mandibular distraction endpoint was

introduced. (15)(21) Preoperative virtual surgical plan-

ning using patient 3-dimensional computed tomography

for skeletal reconstruction and soft-tissue airway volume

calculations is useful and may serve as an objective ad-

junct in preoperative guidance and postoperative follow-

up. (8) Figure 4 exhibits a clinical example.

TABLE 2. Severity of Obstructive Sleep Apnea in Children (11)(12)(13)

CATEGORY OF SEVERITY APNEA-HYPOPNEA INDEX MINIMUM OXYGEN SATURATION

Mild <5 <90% for 2%–5% of sleep time

Moderate 5 to <10 <90% for 5%–10% of sleep time

Severe >10 <90% for >10% of sleep time



MDO OUTCOMES

Reported clinical outcomes of MDO are varied. Metrics

include avoiding a tracheostomy or performing successful

decannulation of the tracheostomy, meeting normal growth

and developmental milestones, weaning from continuous

positive airway pressure, and/or alleviating or significantly

improving obstructive sleep apnea symptoms. Data com-

piled from systematic reviews and meta-analyses demon-

strate that 82% to 100% of patients had an overall positive

outcome fromMDO. In particular, normal oral feeding was

achieved in 86% to 100% of patients, and the axial skeleton

growth curve normalized after 1 year in almost all cases. (8)

(18)(22)(23) MDO is more likely to be successful in relieving

UAO and result in tracheostomy avoidance in patients with

nonsyndromic PRS compared with syndromic PRS with

cognitive comorbidities; those with a syndromic condi-

tion with a disrupted mandibular growth center; and those

without mandibular condyles, coronoid processes, or mal-

formed glenoid fossas. (3) A previously mentioned litera-

ture review found a success rate of avoiding tracheostomy

or achieving successful decannulation in 97.6% of pa-

tients with isolated PRS who underwent MDO compared

with 94% in patients with syndromic PRS in subgroup

analysis. (18)

High success rates fromMDO depend on proper patient

screening and selection. In addition to assessing for con-

comitant central sleep apneas and/or airway pathology

with PSG and nasopharyngeal endoscopy, it is important

to consider other systemic comorbidities that may affect

MDO outcome. Specifically, if MDO is performed on patients

with neurologic comorbidities, the surgery will not address

underlying conditions such as chronic aspiration, hypotonia,

and poor oral coordination, thus unnecessarily exposing the

patient to surgical complications without achieving significant

improvement in airway obstruction. (3)

MDO COMPLICATIONS

Short-term and long-term risks and complications associ-

ated with MDO are listed in Table 3. The overall complica-

tion rate of MDO is between 20.5% and 35.6%. (8)(17)(18)

(24)

Commonly cited short-term complications include infec-

tion, inappropriate vectors of distraction (ie, direction or

differential length of distraction between sides) resulting in

malocclusion, device malfunction, fusion error (eg, prema-

ture bony healing or nonunion of bone segments), and

nerve damage or palsy of the inferior alveolar nerve and/

or the marginal mandibular nerve. The long-term compli-

cations attributable to MDO are not yet fully elucidated, but

include malocclusion, relapse, tooth injury or abnormality,

hypertrophic scarring, and limited mandibular range of

motion. (1)(8)(17)(18)(24)(25) Data on complications include

the following:

• Infections: Infections from MDO vary in their severity

from superficial cellulitis to deep infections or osteo-

myelitis requiring device removal (incidence of 0.5%–

0.9%). (24)• Tooth abnormalities: The tooth-related injuries seen in 1.3%

to 22.5% of patients are mainly caused by damage to un-

erupted molar buds during the MDO procedure. (24) A

retrospective study of 10 infants with PRS treated with

Figure 3. University of Chicago Hospital mandibular distraction osteogenesis timeline and protocol for patients with Pierre Robin sequence (PRS).CT¼computed tomography; MDO¼mandibular distraction osteogenesis; OSA¼obstructive sleep apnea.



MDO and followed for over 5 years demonstrated

statistically significant position changes, shape anomalies,

and root malformations of molars compared with matched

controls. (22)

• Hypertrophic scarring: Hypertrophic scarring of the

submandibular skin incisions, seen in 2.1% to 16.6% of

patients, can necessitate scar revision. (1)(24) In 1 study,

scar revision was recommended for 15% of patients. (3)

• Inferior alveolar nerve damage: The inferior alveolar

nerve may be damaged during the MDO procedure and

further aggravated by stretching during the distraction

phase. Distraction rates over 1 mm/day are associated

with a greater incidence of inferior alveolar nerve tran-

sient hypesthesia. (24)(26) There is a need for more

investigation into the permanency of nerve damage from

MDO.

There is some disagreement over whether relapse,

defined as an increase in the sagittal overbite from its

measurement immediately after MDO, should be consid-

ered a surgical complication or a normal postoperative

phenomenon observed after MDO in skeletally immature

patients with developmentally abnormal mandibles. (24)

Relapse has been estimated to occur in up to 64.8% of

patients who have undergone MDO. (24) Recurrence of

significant UAO may require a second MDO procedure

(w2.2% of patients) or tracheostomy placement for persis-

tent obstruction (w2.2%). (18)

The ideal age at which to undertake MDO is worthy of

discussion. It has been shown that MDO can treat patients

Figure 4. Clinical case. A 3-day-old female neonate with isolated Pierre Robin sequence (PRS), and wide Veau II cleft palate underwent multidisciplinaryevaluation. She was found to have severe obstructive sleep apnea on polysomnography (PSG) (preoperative apnea-hypopnea index 35.91, nadiroxygen saturation high 80s), and deemed a surgical candidate for mandibular distraction osteogenesis. She underwent virtual surgical planning (VSP)preoperatively. A) Preoperative computed tomography scan with oblique orientation of mandibular osteotomies. B) VSP-calculated simulatedplacement of a 70-degree curvilinear distractor, with planned total advancement of 14.7 mm bilaterally. C) VSP-calculated preoperative airway volume(1,065 mm3). D) VSP-simulated postoperative airway volume (1,497 mm3) with planned mandibular distraction. At age 3 months and weight 3.0 kg,she underwent placement of the planned distractors. The latency phase was 24 hours, and distraction phase was 26 days with total mandibularadvancement of 14 mm on the right and 10 mm on the left. Postdistraction PSG showed apnea-hypopnea index to be 2.6, and nadir oxygen saturationof 71%. The consolidation phase was 6 weeks. E) Soft tissue and F) bone changes after consolidation phase, before distractor removal.



with PRS who are only days old, but the smaller mandible

size and lack of mineralization compounds the surgical

complexity of distractor placement in this patient popula-

tion. (27) One study found that patients older than 5 months

had relatively fewer major postoperative complications;

however, no statistically significant difference was found

between overall complication rates in newborns and older

infants. (27) Of note, adult patients have a worse prognosis

after MDO, perhaps because of the reduced ability of adult

mesenchymal stem cells to differentiate under the mechan-

ical stress of distraction. (28)

Experience of the operating surgeon is another factor that

affects MDO success. Surgeons who perform 10 or fewer

craniofacial distractions per year have a complication rate as

high as 55.6%, compared with the average 35.6% reported for

MDO surgeries performed by experienced practitioners. (29)

MDO DEVICES—EXTERNAL AND INTERNAL

Mandibular distractors are available in 2 main categories:

internal (Fig 4) and external devices (Fig 5). The most

apparent difference between the external and internal dis-

traction devices is their visibility and amount of facial

obstruction. Internal devices, with no visible external hard-

ware, have been cited to reduce parental anxiety, allow faster

return to school or daycare, and facilitate breastfeeding. (8)

(30) In addition, because the average distraction phase for

internal devices is shorter, children undergoing internal

distractor placement also experience reduced hospital

length of stay. (8) Internal distractors have a lower risk of

pin site–associated infections and by their nature, necessitate

less wound care. The potential downside of internal devices is

the inability to modify the vector of distraction after implan-

tation; however, with virtual surgical planning and the ability

to place internal devices more precisely, the aforementioned

concern is mitigated. Both internal and external distractors

require a second operation to remove the hardware, though on

occasion, external distractors can be removed under sedation.

Long-term injury of themarginalmandibular branch as well as

greater hypertrophic scarring is cited more frequently with

external distractors. Indications for the external distraction

device have historically included the need for a multiplanar

distraction and ability to immediately address mandibular

asymmetries and open bite deformities during the surgery.

To place internal distractors precisely, computed tomography is

required, which necessitates additional radiation exposure.

(1) However, in the last decade, the development of internal,

multivector, and curvilinear models have facilitated a similar

fine tuning ofmandibular segments compared with that in the

external models. (17)

A comprehensive literature review analyzing 711 pediat-

ric patients younger than 18 years with craniofacial abnor-

malities who underwent MDO between 1992 and 2013

found that when distractor type was specified, a slightly

higher percentage of internal distractors was used by sur-

geons (53.4% to 46.6%), particularly in more recent pub-

lications. The complication rate in this study was 22.1%with

external distractors and 8.3% with internal distractors. (18)

POST-MDO MANAGEMENT

In light of the paucity of data on the long-term stability of

MDO and the concern for tooth injury and long-term mal-

occlusion, routine follow-up with dentistry, orthodontics, oral

TABLE 3. Rate of Complications Associated withMandibular Distraction Osteogenesis

SHORT-TERMCOMPLICATIONS

LONG-TERMCOMPLICATIONS

Infection Malocclusion

• 6% (17) • 2.4% (17) “skeletal openbite”

• 6.3% (18) Relapse

• 9.5% (3) • 64.8% (24)

• 11.8% internal non-resorbable, 12.8% externaldevice, 18.5% resorbable (8)

Tooth injury/abnormalities

• 22% (25) • 1.3% (18)

Inappropriate vector ofdistraction

• 21% (3) molar damage

• 0.67–8.8% (24) • 22.5% (24)

Device malfunction Scarring

• 1.5% (18) • 2.1% (17)

• 2.9% internal nonresorbable,6.4% external device (8)

• 2.3% (18)

• 7.3% (17) • 15.6% (24)

• 7.5–7.9% (24) Limited mandibular rangeof motion

Fusion error • 1.1% (18)• 2.4% (24) premature

consolidation andfibrous nonunion

Nerve damage/palsy• 2% (25)• 2.5% (18)• 5.5% external device, 5.9%internal nonresorbable (8)

• 11.4% (24)



surgery, plastic surgery, and otolaryngology is critical to

achieve sustained success after MDO. As patients age after

MDO, they may require further orthodontic care, aesthetic

surgical procedures such as upper jaw or chin reposition-

ing (genioplasty [cutting and repositioning the chin] or Le

Fort osteotomy [cutting and repositioning the upper jaw]),

and in some cases, repeat MDO. (1)(9)

At the authors’ institution, patients with PRS with cleft

palates typically undergo another PSG before cleft palate

closure to ensure the absence of airway obstruction, because

cleft palate repair, in and of itself, is pro-obstructive. (31) After

cleft repair, these patients may develop abnormal speech

because of velopharyngeal insufficiency leading to nasal air

emission. (32) Some of the abnormal speech processes ob-

served include hypernasality, hyponasality, velopharyngeal

hypodynamism (functional impairment of the velopharyngeal

apparatus), and replacement of oral sounds with glottal stop

(consonant sound formed by air escape after closed glottis) or

pharyngeal fricatives (sound formed by constricting airflow in

the pharynx). (33) In these cases, early intensive speech therapy

is recommended to correct these issues. Children as young as 1

year old can begin performing exercises to strengthen their

velopharyngealmuscles. If speech therapy alone is insufficient,

surgical interventions should be considered, including enlarge-

ment of the posterior pharyngeal wall, pushback palatoplasty

to lengthen the palate, and pharyngeal flaps. (32) In addition,

children with cleft palates are at increased risk for otitis media

leading to conductive hearing loss. (34) Some institutional

protocols suggest a hearing assessment every 6 months for

patients between 1 and 4 years of age as well as otoscopic

assessment for otitis media. Children with conductive hearing

loss may benefit from insertion of tympanostomy tubes. (34)

MDO—QUALITY OF LIFE IMPLICATIONS

The term “health-related quality of life” (HRQOL) describes

a metric that allows objective evaluation of a treatment’s

impact on the physical, psychological, and social aspects of a

patient’s day-to-day life. HRQOL is an important factor to

include in the outcome metrics of a particular treatment. A

survey study given to caregivers of children who previously

underwent MDO demonstrated a benefit in HRQOL after

MDO. (35) Caregivers felt that MDO provided the largest

benefit in the physical domain, specifically the profile of the

lower face. (35) Generalizability of these data is limited,

given the small sample size (n¼21) and retrospective nature

of this study (with a time gap of 1–4 years). Thus, additional

data are needed on the HRQOL benefit of MDO compared

with other PRS interventions in children. In contrast, data

from an HRQOL study on adult patients undergoing MDO in

France showed that 43% of patients found the treatment

painful, 19% of patients felt some degree of stress during

the course of the procedure, and 17% of patients experienced

sleep alterations. Patients were better able to persevere through

treatments when they had hope for improvement. (36)

SURGICAL ALTERNATIVES TO MDO

TracheostomyTracheostomy has been described as the definitive treatment

for correcting UAO and is considered when other options

fail, in cases of underlying neurologic conditions causing

central apnea, or in cases of subglottic obstruction. Trache-

ostomy is a necessary treatment in approximately 10% of

patients with PRS. (9) In some cases, a tracheostomy is used

as a temporary measure with the goal of decannulation after

the child grows and develops. Tracheostomies are associated

with amorbidity of 43% to 65%,mortality of up to 6%, and the

need for skilled nursing care and additional medical equip-

ment at home. Complications associated with tracheostomy

use include accidental decannulation or mucous plugging

leading to sudden UAO, airway infections, bleeding, stomal

maintenance problems, speech and swallowing delay, granu-

lations, and laryngeal/tracheal stenosis. (3)(8)(37)

Figure 5. External mandibular distractors. Example of external mandibular distractor system in an 8-week old child with severe obstructive sleep apneaassociated with Pierre Robin sequence. A) Frontal view; B) right lateral view.



Tongue-Lip AdhesionTongue-lip adhesion (TLA) is a variant of the glossopexy

procedure. It involves releasing the genioglossus muscle

of the tongue in an attempt to bring the tongue forward

and open the pharyngeal airway to relieve UAO. The

TLA is typically released by 12 months of age. Although

this procedure works well for managing UAO, it tends

to exacerbate dysphagia. Children often have diffi-

culty maintaining adequate nutritional intake with this

procedure and may require prolonged nasogastric or

gastrostomy tube feedings. Over 80% of institutions

have stopped using this procedure, turning more to-

ward alternative methods of nasopharyngeal airway

stabilization. (3)

NONSURGICAL ALTERNATIVES TO MDO

Given the morbidity associated with surgical treatment of

UAO, there is great interest in developing nonsurgical alter-

natives to relieving the obstruction, particularly when conser-

vative measures such as prone positioning, nasopharyngeal

intubation, and continuous positive airway pressure are

inadequate. Nonsurgical treatment of UAO in patients

with PRS should be aimed at pharyngeal wall stabilization

and hypopharynx widening by shifting the tongue ante-

riorly to attenuate the effects of glossoptosis.

In Germany, several studies have demonstrated success

with the use of a removable orthodontic pre-epiglottic baton

plate (PEBP) with a velar extension to treat PRS-associated

UAO (Fig 6). The device is custom made from a patient

maxillary castmodel and is composed of compound soft and

hard acrylic. The device covers the palate and the alveolar

ridges and contains a velar extension, the position of which

is modified under endoscopy. (6) The device is held in place

with suction adhesion, and sometimes requires the addition

of an external wire structure to be secured via adhesive to the

patient’s face.

In patients with isolated UAO who underwent preinter-

vention PSG, the use of a PEBP device significantly im-

proved mixed-airway obstruction index scores 3 months

after application without adverse effects. (38) In many

infants, the use of a PEBP not only significantly improves

UAO, but with reliable therapy, also promotes sucking

and feeding without significant morbidity compared with

a similar device without velar extension. (6) By stimulat-

ing weight gain and improving overall nutritional status,

the use of PEBP in this patient population may obviate the

need for supplemental enteral nutrition.

Figure 6. Pre-epiglottic baton plate (PEBP) with velar extension. A) Diagram representation of the PEBP with velar extension, with each of the alveolar,cleft palate and velar extension components. B) Diagram of a patient with Pierre Robin sequence (PRS), including micrognathia, glossoptosis, cleftpalate, and posterior oropharyngeal narrowing. C) Diagram of PEBP with velar extension demonstrating anterior repositioning of posterior tongue basein a patient with PRS, thus increasing the posterior oropharyngeal space.



By precluding the need for prolonged general anesthesia

and surgical intervention, such as tracheostomy and MDO,

the use of PEBP is an attractive option to address isolated

UAO in patients with PRS. Although data from the German

experience are promising, the use of PEBPs has not yet been

described in the United States.

CONCLUSIONS

Standardized clinical evaluation and management guide-

lines in pediatric units and NICUs are essential to ensure

timely diagnosis, evaluation, and management of UAO in

patients with micrognathia and in those with PRS. Specif-

ically, a multidisciplinary care team is required to ensure

that patients receive proper airway evaluation, necessary

surgical treatments, genetic consultations and subsequent

referrals, and continuous nutrition and speech therapy.

We herein present a flow management algorithm to aid in

identifying and treating patients with PRS.

MDO remains the gold standard surgical treatment

available to definitively relieve UAO in select patients with

PRS. However, it carries morbidity and risk in both the early

and late postoperative period. The exploration of less inva-

sive treatment options, such as the PEBP with velar exten-

sion, may avoid the risks and complications associated with

surgical intervention in a subset of patients with PRS.

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6. Buchenau W, Wenzel S, Bacher M, Müller-Hagedorn S, Arand J,Poets CF. Functional treatment of airway obstruction and feedingproblems in infants with Robin sequence. Arch Dis Child FetalNeonatal Ed. 2017;102(2):F142–F146

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9. Mackay DR. Controversies in the diagnosis and management of theRobin sequence. J Craniofac Surg. 2011;22(2):415–420

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11. Roland PS, Rosenfeld RM, Brooks LJ, et al; American Academyof Otolaryngology—Head and Neck Surgery Foundation. Clinicalpractice guideline: polysomnography for sleep-disorderedbreathing prior to tonsillectomy in children. Otolaryngol Head NeckSurg. 2011;145(1 suppl):S1–S15

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15. Zellner EG, Mhlaba JM, Reid RR, Steinbacher DM. Doesmandibular distraction vector influence airway volumes andoutcome? J Oral Maxillofac Surg. 2017;75(1):167–177

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17. Verlinden CRA, van de Vijfeijken SECM, Tuinzing DB, Jansma EP,Becking AG, Swennen GRJ. Complications of mandibulardistraction osteogenesis for developmental deformities: asystematic review of the literature. Int J Oral Maxillofac Surg.2015;44(1):44–49

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American Board of PediatricsNeonatal-Perinatal ContentSpecification• Know the associations and clinical features and management ofmacroglossia and hypoplastic mandible, including the PierreRobin syndrome.



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1. A newborn patient presents with the clinical triad of micrognathia, glossoptosis, and upperairway obstruction (UAO) and is identified as having Pierre Robin sequence (PRS). Theincidence of PRS varies by race and ethnicity and has been found to be highest in patientswith which of the following background?

A. Asian/Pacific Islander.B. White.C. African American.D. American Indian/Alaska Native.E. Hispanic.

2. The newborn patient with PRS has signs of respiratory distress including grunting andsubcostal retractions. The primary objective of PRS treatment is to secure a safe airwaybeginningwith conservative and noninvasivemeasures such as continuous pulse oximetrymonitoring, and prone or side positioning. What is the proportion of infants that canbe stabilized with positioning changes alone?

A. 10%.B. 25%.C. 50%.D. 70%.E. 90%.

3. The newborn patient with PRS has been stabilized and management plans are beingdiscussed with the parents. Mandibular distraction osteogenesis (MDO) has become thepreferred surgical option atmany institutions for neonates and infants with PRS-associatedUAO. The treatment involves an initial surgery to place the device, followed by a 3-phasedistraction period that includes a latency phase, a distraction phase, and a consolidationphase. Which of the following statements regarding MDO is CORRECT?

A. During the distraction phase, the mandibular segment is typically advanced by1 mm daily.

B. The latency phase is typically is a 48- to 72-hour period after distractor placementand before the start of distraction.

C. A 12-week consolidation phase is necessary to allow for complete bone healing.D. Mandibular distraction is considered complete once the mandible is advanced

beyond a standardized anatomic endpoint.E. Overcorrection of themandible is recommended to ensure appropriate relief of the

UAO.

4. The patient with PRS is preparing for the MDO procedure. While data from systematicreviews and meta-analyses indicate that 82% to 100% of patients have an overall positiveoutcome from MDO, short- and long-term complications have been described. Whichof the following statements is CORRECT regarding MDO complications?

A. The overall complication rate of MDO is 10%.B. Osteomyelitis requiring device removal is the most common infection following

MDO with an incidence of 1.8%.C. The tooth-related injuries seen in as many as 22.5% of patients are mainly caused

by damage to unerupted molar buds during the MDO procedure.D. Hypertrophic scarring of the submandibular skin incisions is uncommon, occurring

in less than 1% of patients.E. Inferior alveolar nerve damage only occurs in overaggressive distraction rates over

1.5 mm/day.


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5. A newborn patient with PRS is noted to have evidence of UAO. Various surgicaland nonsurgical options are available for patients with UAO not responding toposition changes alone, including tracheostomy and the tongue-lip adhesion (TLA)procedure. Which of the following statements is CORRECT regarding these alternativemethods of treatment?

A. A tracheostomy is a necessary treatment in approximately 25% of patients withPRS.

B. Tracheostomies are associated with mortality rates as high as 10%.C. The TLA procedure works well for managing UAO, but is no longer performed in a

majority of centers because of the high incidence of feeding difficulties associatedwith it.

D. The TLA is typically released by 6 months of age.E. A custom-made orthodontic pre-epiglottic baton plate has been shown to improve

UAO but is associated with poor feeding outcomes.



DOI: 10.1542/neo.19-5-e2772018;19;e277NeoReviews

Carrie E. Zimmerman, Laura S. Humphries, Tulsi Roy and Russell R. ReidMandibular Distraction for Micrognathia in Neonates

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Carrie E. Zimmerman, Laura S. Humphries, Tulsi Roy and Russell R. ReidMandibular Distraction for Micrognathia in Neonates

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