Copyright @ 2009 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

Mandibular Distraction Osteogenesis to RelievePierre Robin Severe Airway Obstruction in Neonates:

Indication and Operation

Weimin Shen, MD, Cui Jie, MD, Jianbing Chen, MD, Jijun Zou, MD, and Yi Ji, MD

Abstract: Airway management in neonates with Pierre Robin se-quence is often challenging. Advancement of the tongue base usingmandibular distraction in neonates can avoid tracheotomy and isincreasingly propagated. The surgical indication is very important.We establish indication. The result of the preoperative peripheraloxygen saturation of about 40% in the prone position is consideredas indication. The distance from postpharyngeal wall to lingual rootof more than 5 mm is considered as contraindication; however, dis-tance of less than 2 mm is considered needing performing mandi-bular distraction in preoperative lateral cephalometric radiograph. Athree-dimensional computed tomographic demonstrating severity ofretrognathia was generated preoperatively in the computed tomog-raphy room. The osteotomies can be performed by extraoral ap-proaches. Nowadays, for precise bone cutting, Surgybone (SilfradentCo., Sofia, Italy) devices have been introduced in maxillofacial sur-gery, which we used for extraoral-approach osteotomies in 6 patientspresented in this study. Distraction was performed after bilateraloblique osteotomy and removed after 1-month fixation in the sec-ond stage. A follow-up examination after removal of the distractorswas performed. Normal appearance and no apnea were observed at6 months’ follow-up.

Key Words: Pierre Robin sequence, mandibular distraction,neonates

(J Craniofac Surg 2009;20: 1812Y1816)

P ierre Robin sequence (PRS) is the triad of micrognathia,glossoptosis, and cleft palate.1 Neonates with this condition

may have severe airway obstruction, which is traditionally managedwith tracheostomy. Because of the high complication rate associated

with neonatal tracheostomy, distraction osteogenesis (DO) is an al-ternative treatment.2,3 In DO, bone is gradually lengthened undertension across a surgically created osteotomy. We describe bilateralmandibular DO for 6 cases with PRS and severe airway obstruction.

MATERIALS AND METHODS

PatientsThis study reviews 6 consecutive neonates diagnosed with

PRS and life-threatening upper airway obstruction from January 1,2007, through December 30, 2008. A multispecialty neonatalobstructive airway team was formed at the Children’s Hospital ofNanjing; the team included a neonatal intensive care unit neo-natologist, a pediatric anesthesiologist, a pediatric otolaryngologist,and a pediatric plastic surgeon to assess these patients. The studyincluded 5 neonatal patients either seen primarily at the NanjingChildren’s Hospital and 1 neonatal patient referred from other in-stitutions for airway management. Traditional management failed inall these patients, including prone positioning and nasopharyngealairway intubation. Six neonatal patients have the clinical manifesta-tions of mandibular micrognathia, glossoptosis, and cleft palateformation (Fig. 1). Patient data are listed for 6 patients in Table 1.

Preoperative ManagementAll management and outcomes for the respiratory distress

were recorded for each neonate. Perinatal feeding history and pres-ence of any other congenital anomalies were also recorded. In themanagement, top priority was assigned to stabilization of the airway.Airway stabilization proceeded from prone positioning with chestroll, to nasopharyngeal airway, to tracheal intubation (either nasalor oral, depending on ease or difficulty). Adequate nutrition wasachieved via nasogastric gavage feeding. If the airway could not bestabilized by positioning or insertion of a soft trumpet via the noseinto the nasopharynx, surgical management (mandibular DO andthe tongue-lip adhesion) was considered. The decision to performsurgery was based on the patient’s clinical status, perceived need forlong-term respiratory support, result of preoperative peripheraloxygen saturation of approximately 40% in the prone position,failure of nonoperative management, and the surgeon’s clinicaljudgment. A three-dimensional computed tomographic (CT) scanof the head (Fig. 1) was obtained before distraction for surgicalplanning to define the mandibular anatomy and, specifically, toidentify the inferior alveolar nerve foramina on the lingual corticesof the mandibular rami and distal tooth buds in the mandibularbodies, and lateral cephalogram in prone position was obtained. Thedistance was measured from postpharyngeal wall to lingual root. Thedistance from postpharyngeal wall to lingual root was listed for 6patients (Table 2). Decision of mandibular distraction was madethrough clinical symptom and the distance from postpharyngeal wallto lingual root. The distance from postpharyngeal wall to lingual

ORIGINAL ARTICLE

1812 The Journal of Craniofacial Surgery & Volume 20, Supplement 2, September 2009

From the Department of Plastic Surgery, Nanjing Children’s HospitalAffiliated to Nanjing Medical University, Nanjing, China.Received January 6, 2009.Accepted for publication February 18, 2009.Address correspondence and reprint requests to Weimin Shen, MD,

Department of Plastic Surgery, Nanjing Children’s Hospital Affiliatedto Nanjing Medical University, Nanjing, China 210008; E-mail:shenweimincn@hotmail.com

This article did not require any sources of funding.The authors declare that they had no financial interests or commercial

associations during the course of this study.Copyright * 2009 by Mutaz B. Habal, MDISSN: 1049-2275DOI: 10.1097/SCS.0b013e3181b6c388

Copyright @ 2009 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

root of less than 3 mm is considered needing performing mandibulardistraction in preoperative lateral cephalometric radiograph.

OperationThe operations were performed under general anesthesia

using a percutaneous inframandibular border approach. The skinincision is then placed symmetrically approximately 15 to 20 mminferior to this area.

The skin is injected with 0.5% lidocaine hydrochloride with1:200,000 epinephrine. Once the incision is made, the subcutaneousfat is then swept in an inferior-to-superior fashion with a periostealelevator. Dissection should be performed deep to the superficiallayer of the deep cervical fascia because the marginal mandibularnerve lies within or just deep to this layer and passes superficial tothe facial vasculature. Dissection is continued until the pterygo-masseteric sling along the posterior and inferior borders of themandible is identified. Gentle, blunt dissection is performed untilthe muscle fibers of the pterygomasseteric sling remain, whichminimizes the risk of injury to the marginal mandibular branch. Thepterygomasseteric sling is excised with needlepoint cautery along itsinferior edge to expose the buccal cortex of the mandible. Subperi-osteal dissections are then performed along the buccal and lingualcortices. The osteotomy line is outlined on the bone with a No. 2pencil. The oblique osteotomy is planned while maintaining ade-quate bony segments on either side of the osteotomy to allow goodfootplate fixation (Fig. 3). We perform osteotomy with surgybonedevices to achieve clean bony cuts with minimal bone loss or heatgeneration. A side-biting cutting burr can be easier to control; how-ever, this method sometimes results in bone loss at the osteotomysite. Irrigation of surgybone devices should be used copiously during

osteotomy because thermal injury can impair reparative callus for-mation, thereby inhibiting the distraction process. Unidirectionalinternal microdistractors (Cibei Inc) with 1-mm raised-head self-tapping, self-drilling screws are used for most distractions in neo-nates (Fig. 4). The raised-head screws allow easy placement andremoval. We have found bone growth over the flat-head screws atthe time of distractor removal. Predrilling the mandible with a pilothole is not required in patients at this age and may result in poorscrew fixation. We have used a variety of distractors for mandibularDO in children.

We prefer the oblique osteotomy. The oblique osteotomybegins from the anterior ramal border to the posterior border of themandibular angle. Next, buccal corticotomy is performed, except atthe inferior border, where it is bicortical. The distraction device isthen temporarily fitted into the operative site on the basis of apredetermined vector, and its footplates are tailored to accommodateit. A puncture site is made in the postauricular area. A hemostat isthen passed through this puncture site into the wound to grasp theactivating arm of the distractor device, and the activator is pulledthrough the puncture site. Once the distractor is secured, thezcorticotomy is converted to an osteotomy with a 2-mm osteotome.The device is then activated, and the mandibular segments arechecked to see that they are easily distracted. Failure to move thesegments easily signifies incomplete osteotomy, and the site must beinspected, and any remaining bony bridges osteotomized, which issometimes easier to accomplish with the mandible under tension.Once the segments distract easily, the distractor is closed down, andthe segments are brought back in close approximation within a1-mm gap (Fig. 5). The incision is then packed off, and the con-tralateral device is placed in a similar fashion. The wound is irrigated

FIGURE 1. Three-dimensional CT scans and lateral photographs before operation. A and B, Preoperative photographs of the sixthpatient. C, Preoperative three-dimensional CT scan of the sixth patient. Three-dimensional CT scan demonstrating severity ofretrognathia.

TABLE 1. Patient Data

Patient Age, d Birth Weight, gMandibular Deficiency,

mmHospitalDays

Advancement,mm

DaysIntubated Complications

1 17 3500 8 14 9 2 None2 21 2700 18 13 20 3 None3 7 8600 16 15 18 4 None4 5 3600 16 14 16 2 None5 9 4200 11 12 12 3 None6 1 4800 20 14 21 3 None

The Journal of Craniofacial Surgery & Volume 20, Supplement 2, September 2009 Pierre Robin Sequence Airway Obstruction

* 2009 Mutaz B. Habal, MD 1813

Copyright @ 2009 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

copiously with antibiotic solution. The pterygomasseteric sling isreconstructed with a polyglactin 4-0 (Vicryl; Ethicon Inc) suture.Restoring the sling is important in functional loading and remodelingof the mandible. The dermis is approximated with a polyglactin4-0 (Vicryl; Ethicon Inc) suture, and skin is closed with a runningsubcutaneous 6-0 polypropylene (Prolene; Ethicon Inc) suture. Twoweeks after surgery, 1 end of the subcutaneous polypropylene su-ture is cut and removed (Fig. 6).

RESULTSThis group was composed of 6 neonates with isolated PRS.

Six neonates required intubation and ventilator support before op-eration to maintain ventilation. All patients had intermittent restingoxygen saturation levels of less than 40% before operation. Furtherdeterioration was noted during feeding in some patients. Age atoperation was 7 to 21 days (mean, 13.14 days; median, 6.5 days).One neonate (patient 2) had severe growth retardation when ini-tially evaluated and underwent nasogastric feeding support until heweighed 3.5 kg. In 1 case, a tongue-lip adhesion was performed.Mandibular distraction was performed after the failure of tongue-lipYadhesion management. Mandibular distractors were placed du-ring operation with the patient under general anesthesia, and asurgical separation was created in the ramus of the mandible. Allprocedures were completed in less than 2.5 hours, with less than40 mL of blood loss. The patients were kept intubated, and dis-traction was initiated on postoperative day 1 at a rate of 1.2 mm/d,then switched to a rate of 1 mm/d after 6 mm of distraction. Wenormally use a 60-mm distractor and distract either to the full lengthof the 20 mm or until the mandibular gum line is 0 to 2 mm in front

of the maxillary gum line, whichever occurs first. The overcorrectionis performed to compensate for the regenerative contraction thatcan occur. We use a 4-week consolidation period before distractorremoval, which is performed through the previous incision with asmall posterior extension to account for the length added to thedistractor. All cases were not complications. All patients wereextubated within 4 to 6 days of distractor activation. A good clini-cal indicator of successful distraction was correction of the tonguefrom the initial vertical to a physiologically normal horizontal pos-ture on physical examination. Nasoendoscopy was performed withthe patients under sedation to confirm the relief of tongue-base ob-struction before the patients were extubated. None of the patientsneeded any form of supplemental oxygenation beyond 20 days af-ter operation. None of the patients who underwent distractionneeded any additional airway support, treatment, or surgery. Na-sogastric gavage feeding was started on the first day after surgery.All neonates were feeding 100% orally at 1 month of age (as inpatient 6 in Fig. 7).

DISCUSSIONPierre Robin,1 a French stomatologist, first reported the

association of micrognathia, glossoptosis, and cleft palate in 1923.By 1974, the triad was known as the Pierre Robin sequence, whichindicates that it is a condition that includes a series of anomaliescaused by a cascade of events initiated by a single malformation.The primary malformation in PRS is thought to be mandibularmicrognathia, which causes glossoptosis and cleft palate formation.4

There are various options for airway management for a patient withPRS. It is reasonable to begin with the most conservative measures,such as placing a nasopharyngeal airway and keeping the child ina prone position. Positive-pressure mask ventilation of the airwayis also beneficial. Other options include glossopexy procedures,tongue-lip adhesions, or subperiosteal release of the floor of themouth combined with glossopexy.5 The literature suggests that thetongue-lip adhesion could successfully relieve airway obstructionthat is unresponsive to positioning alone in most patients withPRS.6,7 However, complications include dehiscence, infection, sub-maxillary duct obstruction, and lip scarring. Denny et al8 indicatethat long-term follow-ups show a high incidence of secondaryintervention requirements. For the most severe cases, tracheostomyis used to secure a stable airway. Tracheostomy in infancy carries asignificant burden. The mortality rate from the tracheostomy aloneindependent of the underlying diagnosis is as high as 5%.9 However,because of the high complication rate in neonatal tracheostomy,

TABLE 2. Distance from Postpharyngeal Wall to Lingual Rootin Lateral Cephalogram (Fig. 2)

Patient Preoperation, mm Postoperation, mm

1 1 92 2 113 2 124 3 105 2 126 1 20

FIGURE 2. Distance from postpharyngeal wall to lingual root in lateral cephalogram before (A) and after (B) operation of the sixthpatient.

Shen et al The Journal of Craniofacial Surgery & Volume 20, Supplement 2, September 2009

1814 * 2009 Mutaz B. Habal, MD

Copyright @ 2009 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

other innovative surgical procedures have been recently applied.Mandibular distraction is an effective way to treat PRS patients andavoids a tracheostomy in 90% to 95%.10 Mandibular DO to treatairway obstruction from micrognathia in PRS offers many ad-vantages over other surgical options. After osteotomy, DO is usedto induce new bone formation between bony surfaces that are grad-ually separated. In 1973, Snyder et al11 reported the first ex-perimental craniofacial application of DO in a canine model. Thefirst clinical report of craniofacial DO was published in 1992 byMcCarthy et al.12 They described gradual mandibular elongation inpatients with congenital hypoplasia. There have been recent reportsof successful DO for airway obstruction in the management ofchildren with micrognathia. Sidman et al13 prospectively evaluated11 children with tongue-base airway obstruction who were treatedwith mandibular DO. Decannulation or extubation was achieved inall cases. Similarly, Monasterio et al14 successfully used mandibularDO in 15 pediatric patients with airway obstruction. Denny andKalantarian15 applied mandibular DO in 5 neonates, and tracheot-omy was avoided in all cases. Mandell et al16 reported an 88%success rate in 8 children with PRS treated with DO. More recently,Roy and Patel17 described 8 children with PRS who were success-fully treated with mandibular DO using the same internalmicrodistractor that was used by our team. These studies showthat DO is successfully used to achieve mandibular advancement.With this technique, the genioglossus and geniohyoid muscles andthe tongue base are brought forward, and the supraglottic airwayobstruction is relieved in patients with micrognathia.

In neonates with PRS, several surgical procedures have beendescribed to manage the airway. Especially, tongue-lip adhesion hasbeen advocated to relieve the airway obstruction and is propagatedby Danielle and Jeffrey18 as first-line treatment of severe airwayobstruction associated with PRS. In this article, the authors em-phasized indication of operation. The surgical indication is veryimportant. The result of the preoperative peripheral oxygen satu-ration of about 40% in the prone position is considered as theindication. The distance from postpharyngeal wall to lingual rootabove 5 mm is considered as contraindication; however, less than2 mm is considered needing performing mandibular distraction inpreoperative lateral cephalometric radiograph. Less than 2 mm isconsidered needing performing tracheostomy. Mandibular DOavoids a tracheostomy. The reasons for the indications of mandibularDO, as we chose, were that the patients could not improve respi-ration when their oxygen saturation as measured by pulse oximetrywas less than 40% in the prone position. At this condition, we mustperform the tracheostomy. When the distance from postpharyngealwall to lingual root was less than 2 mm, we also need to perform the

FIGURE 3. The oblique osteotomy is designed on digit model.

FIGURE 4. Distractor in neonates.

FIGURE 5. The segments are brought back in closeapproximation within a 1-mm gap.

FIGURE 6. Neonate after polypropylene suture was removed(6 days).

The Journal of Craniofacial Surgery & Volume 20, Supplement 2, September 2009 Pierre Robin Sequence Airway Obstruction

* 2009 Mutaz B. Habal, MD 1815

Copyright @ 2009 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

tracheal cannula or the tracheostomy as respiration could not beimproved for the operation of tongue-lip adhesion. Therefore, it isnecessary for mandibular DO. However, DO does have limitations inthe treatment of neonatal micrognathia. First, the procedure offersonly a gradual improvement in the airway. The distraction usuallyprogresses at a rate of 0.5 to 1.2 mm/d. Thus, the airway must besecured by some other means (endotracheal tube or tracheotomy)and intensively monitored throughout the distraction. Second, theDO device can be unwieldy, and the entire procedure is labor-intensive. Extreme care must be taken to ensure that the deviceremains securely attached to bone and that the screws are turnedappropriately. Patient data must be accurately charted. The nursingstaff and parents must diligently care for the incision and post sites.Third, the effect of mandibular DO on dental development iscontroversial. Injury to premolar tooth buds during the osteotomymay render them nonviable. Additional anatomic concerns includeinjury to the marginal mandibular branch of the facial nerve and theinferior alveolar nerve and asymmetry of face. If we can ensurecorrect indications and careful operative procedure, the adversefactors can be avoided. Most preliminary reports show favorablemandibular growth after DO for children with PRS.2,3 This allowsthe child to be successfully extubated or decannulated and typicallyallows the child to begin a regular oral diet. Patients must fulfillseveral criteria before mandibular DO is performed. The surgeonmust be certain that the patient has adequate mandibular bone stockand the level of anoxia. Distance from postpharyngeal wall to lingualroot must be established in lateral cephalogram. A preoperative

comprehensive airway endoscopy is essential to rule out any otherpathologic finding. A tracheal intubation can be performed; thisshould provide temporary relief of the airway obstruction. If thepatient does not meet these criteria, then tracheotomy should bestrongly considered.

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respiratory disturbances. Bull Acad Med 1923;89:37Y412. Fritz MA, Sidman JD. Distraction osteogenesis of the mandible. Curr

Opin Otolaryngol Head Neck Surg 2004;12:513Y5183. Denny AD. Distraction osteogenesis in Pierre Robin neonates with

airway obstruction. Clin Plast Surg 2004;31:221Y2294. Taylor MR. Consultation with the specialist: the Pierre Robin sequence:

a concise review for the practicing pediatrician. Pediatr Rev 2001;22:125Y130

5. Corstiaan CB, Peter RO, Donald GF. Subperiosteal release of the floorof the mouth in airway management in Pierre Robin sequence.J Craniofac Surg 2008;19:609Y615

6. Hoffman W. Outcome of tongue-lip placation in patients with severePierre Robin sequence. J Craniofac Surg 2003;14:602Y608

7. Kirschner RE, Low DW, Randal P, et al. Surgical airway management inPierre Robin sequence: is there a role for tongue-lip adhesion? CleftPalate Craniofac J 2003;40:13Y18

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9. Kremer B, Botos-Kremer AI, Eckel HE, et al. Indications,complications, and surgical techniques for pediatric tracheostomiesVanupdate. J Pediatr Surg 2002;37:1556Y1562

10. Denny A, Amm C. New technique for airway correction in neonateswith severe Pierre Robin sequence. J Pediatr 2005;147:97Y101

11. Snyder CC, Levine GA, Swanson HM, et al. Mandibular lengtheningby gradual distraction: preliminary report. Plast Reconstr Surg 1973;51:506Y508

12. McCarthy JG, Schreiber J, Karp N, et al. Lengthening the humanmandible by gradual distraction. Plast Reconstr Surg 1992;89:1Y8

13. Sidman JD, Sampson D, Templeton B. Distraction osteogenesis of themandible for airway obstruction in children. Laryngoscope 2001;111:1137Y1146

14. Monasterio FO, Drucker M, Molina F, et al. Distraction osteogenesisin Pierre Robin sequence and related respiratory problems in children.J Craniofac Surg 2002;13:79Y83

15. Denny A, Kalantarian B. Mandibular distraction in neonates: a strategyto avoid tracheostomy. Plast Reconstr Surg 2002;109:896Y904

16. Mandell DL, Yellon RF, Bradley JP, et al. Mandibular distractionfor micrognathia and severe upper airway obstruction. Arch OtolaryngolHead Neck Surg 2004;130:344Y348

17. Roy S, Patel PK. Mandibular lengthening in micrognathic infants withthe internal distraction device. Arch Facial Plast Surg 2006;8:60Y64

18. Danielle D, Jeffrey LM. Mandibular distraction osteogenesis for PierreRobin sequence: what percentage of neonates need it? J CraniofacSurg 2008;19:1237Y1243

FIGURE 7. Infant after mandibular distraction.

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1816 * 2009 Mutaz B. Habal, MD