Combined maxillary and mdistraction osteogenesis inhemifacial microsomia

Eduardo Franzotti Sant'Anna,a Georgia W. T. Lau,b MarianJohn W. Polley,d and Alvaro A. Figueroad

Rio de Janeiro, Brazil, and Chicago, Ill

Introduction: Hemifacial microsomia is a deformity of vamandible and the ear. In this study, we evaluated skeletal sdistraction.Methods: Eight patients (4 preadolescents 4 adunderwent a LeFort I osteotomy and an ipsilateral horizontation device was placed over the ramus, and intermaxillaryand frontal photographic analyses were conducted before

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laned soft tissue planes improved, with an increase in the

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ponents, neural, muscular, and soft tissues are also

The treatment of HFM is centered on the mandibular

aAssoDentipostdRushbPhDFederfellow

All authors have completed and submitted the ICMJE Form for Disclosure of Po-tential Conicts of Interest, and none were reported.

0889-5406/$36.00Copyright 2015 by the American Association of Orthodontists.

ORIGINAL ARTICLEaffected. The mandibular deformity in HFM was classi-ed by Pruzansky2 in 1969. In his classication, a gradeI mandibular deformity consists of a normally shapedbut small mandible. Grade II is a small and abnormallyshaped mandibular ramus. In grade III, the mandibulardeformity is characterized by absence of the mandibularramus including the temporomandibular joint.

Eduardo Franzotti Sant0Anna and Georgia W.T. Lau are recipients of scholarshipsfrom Coordenac~ao de Aperfeicoamento de Pessoal de Nvel Superior (CAPES),and Eduardo Franzotti Sant0Anna is recipient of grants n. E-26/171.246/2006and n. E-26/111.647/2010 from Fundac~ao de Amparo a Pesquisa do Estadodo Rio de Janeiro (FAPERJ), Brazil.Address correspondence to: Alvaro A. Figueroa, Craniofacial Center, Rush Univer-sity Medical Center, 1725 W Harrison St, Suite 425, Professional Bldg I, Chicago,IL 60612; e-mail, Alvaro_Figueroa@rush.edu.Submitted, April 2014; revised and accepted, December 2014.craniomaxillofacial asymmetry on the affected side.The maxilla, temporal bone, and orbit are also

affected as a result of the primary malformation andnot secondarily affected by the mandibular hypoplasia,as suggested by some.6 In addition to the skeletal com-

Medical Center, Chicago, Ill.cPostdoctoral fellow, Department of Pedodontics and Orthodontics, School ofDentistry, Federal University of Rio de Janeiro; Brazilian Army dentist, SantaMaria, Rio de Janeiro, Brazil.dCodirector, Craniofacial Center, Department of Plastic and Reconstructive Sur-gery, Rush University Medical Center, Chicago, Ill.http:/

566with xed orthodontic appliances and well-aligned dental arches responded well to this intervention. (Am JOrthod Dentofacial Orthop 2015;147:566-77)

emifacial microsomia (HFM) is the best knownbranchial arch syndrome1-3 and the secondmost common craniofacial birth defect after

cleft lip and palate.4-6 It occurs in 1:35005 to 1:56live births. The term HFM refers to an asymmecongenital condition of variable expressivity affectprimarily aural, oral, and mandibular developmeHFM can be part of a broader and variable phenotyspectrum known as oculoauriculovertebral dysplaand always involves mandibular and ear malformatiobut its severity varies.7,8 The mandibular decieusually is associated with microtia, macrostomia, a

ciate professor, Department of Pedodontics and Orthodontics, School ofstry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly,octoral fellow, Department of Anatomy and Rush Craniofacial Center,University Medical Center, Chicago, Ill.student, Department of Pedodontics and Orthodontics, School of Dentistry,al University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly, postdoctoral, Department of Anatomy and Rush Craniofacial Center, Rush Universityaffected side ramus height and correction of the chin point toward the midline. Conclusions: Simultaneousmaxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentitionthe preoperative and postoperative changes. Resultsgonial plane angles decreased. The ratios of affected15% and 20%, respectively. The position of mentonshowed a decrease of the nasal and commissure pThe parallelism between the horizontal skeletal an/dx.doi.org/10.1016/j.ajodo.2014.12.027andibularpatients with

a Marquezan,c Mo^nica Tirre de Souza Araujo,a

riable expressivity with unilateral hypoplasia of theoft tissue changes after bimaxillary unilateral verticalolescents) each with a grade II mandibular deformityl mandibular ramus osteotomy. A semiburied distrac-xation was applied. Anteroposterior cephalometricand after distraction. Statistics were used to analyzephalometrically, the nasal oor and the occlusal andffected ramus and gonial angle heights improved byved toward the midline. The photographic analysisangles, and the chin moved to the unaffected side.deformity, but surgical timing is still controversial. The

Another concern is the psychological adjustment15,16

Sant'Anna et al 567problems caused by differences in facial appearance.Some clinicians consider that the surgery should be doneearlier to prevent social adjustment problems. Others,who prefer to wait for the completion of growth,believe that expectations of reconstructive surgery cancause disillusionment when performed too early,because the patient will still grow asymmetrically andadditional surgery will be required.

The critical step in achieving better facial skeletal har-mony is to restore maxillary and mandibular symmetry.Facial asymmetry is a main indication for orthognathicsurgery. Traditionally, skeletal hypoplastic malformationsare corrected with segment repositioning with autoge-nous bone grafts to increase the volume and size.17

Recently, in patients with HFM, distraction osteo-genesis has been used for correcting mandibular asym-metry.8,18 Mandibular elongation by gradualdistraction is mainly indicated in HFM patients withmandibular deformities grades I and II.19 Since HFM pri-marily affects not only the mandible but also the maxillaand the orbit, clinicians have suggested simultaneousmaxillary and mandibular interventions to correct theseasymmetries with a single procedure.19-21 The purposeof this study was to assess skeletal and soft tissuechanges after simultaneous maxillary and mandibulardistractions in patients with HFM.

MATERIAL AND METHODS

Eight patients with HFM grade II mandibular defor-mity and maxillary asymmetry with a mean age of13 years 2 months underwent combined maxillary andmandibular distractions.3

The surgical procedures were done under generalanesthesia with nasotracheal intubation. A completehorizontal LeFort I osteotomy was performed. Incontrast to the original method of Ortiz Monasterioet al,19 the pterygomaxillary junction was freed with acurved chisel on both sides, not only on the affectedreason for this controversy relates to what cliniciansbelieve is the facial growth potential in patients withHFM. Those who support early reconstruction, beforeskeletal maturity, assume that the mandibular skeletalasymmetry will worsen with time, and that early recon-struction will prevent secondary growth defor-mities.5,9-11 However, studies have found that thegrowth of the mandible on the affected side parallelsthat of the unaffected side, with the degree ofasymmetry remaining relatively constant throughoutcraniofacial development.12-14side. The unaffected maxillary side LeFort I osteotomywas loosely secured with 1 surgical wire placed above

American Journal of Orthodontics and Dentofacial Orthopedthe maxillary rst and second permanent molars. Thiswire acted as a hinge and pivot point where the maxillo-mandibular complex was expected to rotate toward theunaffected side (Fig 1).

The ascending ramus was exposed along its anteriorborder behind the last molar and extended to the gonialangle and the surrounding area. The orientation of theosteotomy and the position of the distractor devicedetermined the vector of distraction. A semiburieddistraction device (Zurich II Distraction System; KLSMartin, Jacksonville, Fla) was positioned over the ramusin the planned direction (usually parallel to the long axisof the ramus) and xed with self-tapping screws tosecure the foot plates above and below the initiallyincomplete horizontal ramus osteotomy. The activatingarm, from the semiburied device, was placed externallythrough a small incision below the mandibular angle.The osteotomy was completed and veried by openingthe distractor. Before closure, the device was deacti-vated. The incision was closed, and rigid intermaxillaryxation with surgical wires was applied. Younger pa-tients in the mixed dentition had custom-banded(maxillary and mandibular rst permanent molars) archbars with soldered hooks secured with circumdentalwires for additional support during intermaxillary wirexation and elastic therapy. In the adolescent patients,the orthodontic appliances were used for presurgicalalignment and intermaxillary wire xation and postop-erative elastic therapy.

The extent of the required bone elongation and thevector of the distraction were determined by the severityof the ipsilateral mandibular deformity, the shape of thecontralateral or unaffected mandibular ramus, and thetransverse cant of the occlusal plane. After 7 days (la-tency period), the device was lengthened by 0.5 mmtwice a day, for an average of 22 consecutive days. Inyounger patients, vertical elongation of over 15 mmwas usually not required; therefore, a single 15-mm dis-tractor was able to correct the occlusal plane discrep-ancy. In the adolescent patients who required morethan 15 mm of vertical distraction, we preplanned 2consecutive surgical procedures; after full activation ofthe rst 15-mm distractor, it was removed, and anotherdistractor of 30 mm was placed to complete the requiredvertical distraction. This is a required step, since the boneavailable to xate the device above and below theplanned osteotomy over the ramus is only sufcient toaccommodate a distractor of limited length (usually15 mm). After the initial distraction, a longer distractorcan be placed. This device is partially opened beforeplacement to clear the newly generated bone. Another

reason why in certain patients it is necessary to use 2consecutive devices relates to the fact that the initial

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ilatetal ra); sinectedne foconerm

568 Sant'Anna et alFig 1. Schematic representation of bimaxillary unmaxillary LeFort I (dashed line), unilateral horizondistractor; intermaxillary wire xation (dotted lineside); vertical and curved arrows indicate the expments after distraction. B, Expected vertical bomedial rotation of the maxilla and mandible to theand restoration of symmetry. (Reproduced with pplacement is such that true vertical elongation is not ob-tained. The placement of the device has mainly a verticalcomponent with a forward and medial vector because ofthe shape of the hypoplastic ramus and the contralateralramus that needs to be emulated to correct as much aspossible not only the size but also the form of the ramus.The placement of the distractor in this manner results inan effective loss of vertical length. Semiburied distrac-tors are rigid and true to their length, but as explainedabove, the skeletal change is less than the true expres-sion of the distractor; therefore, the activation to skeletalchange ratio is not 1:1.

The goal of bimaxillary distraction is mainly to obtaina level occlusal plane and not perfect symmetry of thegonial angles. The reason is that the vertical discrepancyis usually greater at the gonial angles, and if they are lev-eled, the occlusal plane will be canted downward on theaffected side. The gonial angle asymmetry can be ad-dressed secondarily with bone grafting combined withother required procedureseg, genioplasty or soft tissueaugmentationto further improve appearance.

Activation of themandibular distractor resulted in ver-tical elongation of the affected ramus and medialdisplacement of both themaxillary andmandibular denti-tions toward the unaffected side. This was possiblebecause the patients had a complete affected side hori-zontal ramus osteotomy and a complete LeFort I

May 2015 Vol 147 Issue 5 Americanral vertical distraction surgical plan.A,Completemus osteotomy; mandibular buried single-vectorgle wire acting as a hinge (circle, contralateraldirection of the maxillary andmandibular move-rmation between osteotomies, downward andtralateral side with leveling of the occlusal planeission from Figueroa and Polley.21)osteotomy. In addition, they were placed in intermaxillarywire xation to move the maxilla, the mandible, and thedentition as a unit. The patient's preoperative occlusionwas preserved through intermaxillary wire xation duringdistraction. After distraction, a consolidation period withwire intermaxillary xation was completed (4 weeks forthe younger patients and up to 6 weeks for the adolescentpatients). After this period, the wires were replaced with6-oz, -in orthodontic elastics for the next 3 months.

The patients were placed on a liquid diet during theintermaxillary xation period and a soft diet for 4 to6 weeks after the wires were removed. Orthodontic treat-ment was continued in the adolescent patients for 6 to8 weeks after the wire xation was removed. In theyounger patients, the xation appliances were removedafter 2 to 3months of elastic therapy. The distraction de-vice was left in place for 6 months and removed in theoperating room under general anesthesia.

All patients had anteroposterior (AP) cephalometricradiographs and clinical frontal photographs taken beforeand after distraction in a standard manner. Skeletal andsoft tissue facial asymmetries were respectively measuredwith AP cephalometric and soft tissue photographic fron-tal analysis. Radiographs and photographs were handtraced by the same investigator (E.F.S.). Each measure-ment was repeated 3 times, and the mean was recordedfor data comparison. There was no statistical difference

Journal of Orthodontics and Dentofacial Orthopedics

r the

e

e

points

Sant'Anna et al 569Table I. Description of the cephalometric AP analysis fo

Measurement DenitionVertical angle measurements

HL-Co0Co Angle between the HL and the bicondylar plan

HL-NF0NF Angle between the HL and the nasal oor plan

HL-J0J Angle between the HL and the maxillary jugalbetween the 3 measurements as determined by the Dahl-berg22 double determination method.

The measurements from the AP cephalograms aregiven in Table I. Two reference lines were traced(Fig 2) and used to make vertical and horizontal mea-surements: a horizontal line (HL), the line connectingthe right and left latero-orbitale points, and a verticalline (VL), the line perpendicular to the HL through thecenter of crista galli (most constricted point of the pro-jection of the perpendicular lamina of the ethmoid).

HL-OCP Angle between the HL and the occlusal plane

HL-Go0Go Angle between the HL and the gonial plane

Horizontal angle measurementsVL-isf Angle between the VL and the superior midline

VL-Me Angle between the VL and the mental line

Tns-ANS Angle between the VL and the nasal septum

Fig 2. Cephalometric analysis of vertical and horizontaandVL references used for analysis: 1, HL-Co0CobiconJ0J maxillary jugal plane; 4, HL-occlusal plane; 5, HL-analysis: 1, VL-isf superior midline; 2, VL-Me mental lin

American Journal of Orthodontics and Dentofacial Orthopedvertical and horizontal measurements

Landmark

Condylion (Co), external lateral marginal portion of thecondylar head

Nasal oor (NF), most inferior point on inside surface of thebony nasal cavity

Jugal process (J), bilateral points on the jugal process of theThe gonial height ratio (HL-Go0/HL-Go) and theramus height ratio (CoGo0/CoGo) were calculated fromthe AP cephalograms to compare the affected vs the un-affected sides. HL-Go0/HL-Go is the ratio between thelinear perpendicular distance from the horizontal refer-ence line to the affected Go0 point, and the linearperpendicular distance from the horizontal referenceline to the unaffected Go point. Co0Go0/CoGo is the ratiobetween the linear perpendicular distance from theaffected Co0point to the affected Go0point, and the linear

maxilla at a crossing with the tuberosity of the maxillaOcclusal plane (OCP), horizontal plane passing through the

molar and the incisorsGonion (Go), most lateral and inferior point of the

mandibular angle

Incision superior frontale (isf), midpoint between themaxillary central incisor at the level of the incisal edges

Menton (Me), point on the inferior border of the symphysisdirectly inferior to the mental protuberance

Anterior nasal spine (ANS), tip of the ANS below the nasalcavity and above the hard palateTop of the nasal septum (Tns), the highest point on thesuperior aspect of the nasal septum

l changes.A,Horizontal planes relative to theHLdylar plane; 2, HLHL-NF0NFnasal oor plane; 3,Go0Go gonial plane. B, Vertical planes used fore; 3, Tns-ANS nasal septum deviation to the VL.

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angle (P 5 0.008), the occlusal plane angle (P5 0.003),and the gonial plane angle (P5 0.035). Of the horizontal

plane; 2, HL-ch0ch labial commissure plane; 3, VL-Pogvertical line chin point.

570 Sant'Anna et alperpendicular distance from the unaffected Co point tothe unaffected Go point (Fig 3).

In the photographic facial analysis, we used 3 bilat-eral soft tissue landmarks identied on the frontal pho-tographs: bilateral endocanthion (inner commissure ofthe eye ssure) and the center point of a line connectingthe right and left endocanthions. Two reference lineswere traced on the frontal photographs (Fig 4): an HL,

Fig 3. Cephalometric analysis of the ratio of affected vsunaffected gonial height (HL-Go0/HL-Go) and ramusheight (Co0-Go0/Co-Go).the line connecting the right endocanthion to the leftendocanthion points; and a VL, the line perpendicularto the HL through the midline of the distance betweenthe right and left endocanthion points. The measure-ments obtained from the frontal photographs are shownin Table II.

Statistical analysis

Paired t tests were used to examine the differencebetween the preoperative (T1) and postoperative(T2, 6 months after surgery) measurements using theStatistical Package for Social Sciences software(version15.0; SPSS, Chicago, Ill). The power of the pairedt test was calculated for each variable considering a sam-ple size of 8 and an a of 0.05, using the free softwarepower and sample size calculator (version 3.1.2; Statisti-cal Solutions, Boston, Mass).

RESULTS

The results of the AP cephalometric analysis demon-strated vertical improvement in all patients as seen by sta-tistically signicant decreases relative to the HL of thenasal oor angle (P 5 0.004), the maxillary jugal plane

May 2015 Vol 147 Issue 5 AmericanFig 4. Planes used in the photographic analysis to eval-uate vertical and horizontal facial changes relative to theHL and VL reference lines: 1, HL-sbal0sbal nasal basechanges, only the menton to the VL measurement(P5 0.004) was statistically signicant (Table III).

The ratio of the affected-unaffected gonial height(HL-Go0/HL-Go) signicantly improved by 20% from65.85% to 86.61% (P 5 0.027). Ramus height(Co0Go0/CoGo) also signicantly improved by almost15% from 78.12% to 93.06% (P 5 0.042) (Table III).The ndings demonstrated parallelism among the hori-zontal planes, vertical elongation of the affected sideramus height, and improvement of the midline deviationmeasurements. These were favorable changes towardrestoring symmetry.

The facial photographic analysis (Table IV) demon-strated signicant changes, with the nasal plane improvingby 3.00 (P5 0.014), and the chin position changing to-ward the unaffected side by 4.83 (P 5 0.000), thusimproving the midline symmetry, but without reachingfull correction. Although not statistically signicant, thelabial commissure plane improved by 2.3.

The power of the t test (ie, the probability of correctlyrejecting the null hypothesis) is included in Tables III andIV. Most variables with statistically signicant differ-ences between T1 and T2 (6 of 9) had an over 90% powerfor the t tests.

Journal of Orthodontics and Dentofacial Orthopedics

the

nitio

and tand thtal an

and th

and

Sant'Anna et al 571Table II. Description of photographic facial analysis for

Measurement DeVertical angle measurements

HL-sbal0sbal (nasal base angle plane) Angle between the HLHL-ch0ch (labial commissure angle plane) Angle between the HL

plane, and 1 horizonHorizontal angle measurement

VL-Pog (chin point) Angle between the VL

Table III. Vertical and horizontal angular measurementsDISCUSSION

Reconstruction of an asymmetric mandible associ-ated with a soft tissue deciency is one of the most chal-lenging problems in patients with HFM. Numeroussurgical procedures have been advocated to correctfacial asymmetry in these patients, including costochon-dral grafts, mandibular osteotomies combined with bonegrafts, and maxillary osteotomies, done at an early ageor in late adolescence.6,9,18 The results can beunpredictable because of undesirable resorption of thegraft, leading to decreases in volume and strength ofthe reconstructed area. Furthermore, these procedurescan cause signicant morbidity at the donor site.Conventional orthognathic surgery, such as maxillaryimpaction on the unaffected side, is usually performed

Measurement T1 mean 6 SD T2 mean 6 SDBicondylar plane (HL-Co0-Co) () 3.42 6 2.07 2.14 6 1.46Nasal oor plane (HL-NF0NF) () 14.28 6 6.36 8.00 6 6.55Maxillary jugal plane (HL-J0J) () 11.85 6 6.76 3.00 6 4.12Occlusal plane (HL-OCP) () 12.71 6 5.85 4.42 6 4.07Gonial plane (HL-Go0Go) () 12.42 6 7.18 4.00 6 5.13Superior midline (VL-isf) () 5.71 6 4.95 3.85 6 5.08Mental line (VL-Me) () 7.00 6 7.58 3.4 6 7.05Nasal septum deviation (Tns-ANS) () 14.71 6 6.36 11.14 6 6.36Gonial height (HL-Go0/HL-Go) (%) 78.12 6 14.45 93.06 6 9.32Ramus height (Co0-Go0/Co-Go) (%) 65.85 6 16.01 86.61 6 12.350Affected side.*P\ 0.05; yP\ 0.01.

Table IV. Vertical and horizontal angular measurements fro

Measurement T1 mean 6 SD T2 mean 6Nasal base angle plane (HL-sbal0sbal) () 7.50 6 5.91 4.25 6 5Labial commissure angle plane (HL-ch0ch) () 9.75 6 4.99 6.75 6 6Vertical line-chin point angle (VL-pog) () 8.75 6 6.23 3.75 6 6

0Affected side.*P\ 0.05; yP\ 0.01.

American Journal of Orthodontics and Dentofacial Orthopedvertical and horizontal measurements

n Landmark

he nasal base plane Subalare (sbal), lower limit of each alar basee labial commissuregle measurement

Cheilion (ch) point at each labial commissure

e chin point Pogonion (Pog), most anterior midpoint ofthe chin

ratios from anteroposterior cephalometric radiographs

Difference 95% CI of the difference Power ofwith mandibular osteotomies.17 A large movement hasa high risk for relapse because of the soft tissue de-ciency of HFM. Recently, a complete fossa, condyle,and ramus reconstruction with a prosthetic replacementhas been reported in adolescent patients with HFM withsevere mandibular deformities.23

Distraction osteogenesis has provided an alternativein the treatment of craniomaxillofacial deformities.18

Its success is related to the fact that it uses the body0sown healing mechanisms to produce new bone andelongate the soft tissues. This diminishes the need forautografts, thus decreasing morbidity. Mandibular elon-gation by gradual distraction can be done at any age.19

However, acute changes in mandibular shape result inpostoperative alterations in dental occlusion, such

T1 T2mean 6 SD P value

paired ttest (%)Lower Upper

1.28 6 1.70 0.093 0.29 2.86 41.26.28 6 3.72 0.004y 2.83 9.73 97.78.85 6 6.03 0.008y 2.28 3.27 94.28.28 6 4.46 0.003y 4.15 12.41 98.88.42 6 8.24 0.035* 0.80 16.05 69.31.85 6 3.18 0.174 1.08 4.80 25.03.6 6 2.50 0.033* 0.48 6.71 93.5

3.57 6 4.03 0.058 0.16 7.30 55.514.93 6 13.59 0.027* 2.36 27.50 76.020.76 6 21.37 0.042* 0.99 40.53 64.4

m frontal photographs

SD

DifferenceT1T2

mean 6 SD P value

95% CI of the difference Power ofpaired ttest (%)Lower Upper

.25 3.00 6 2.00 0.014* 0.90 5.09 94.9

.89 2.33 6 3.14 0.128 0.96 5.62 40.0

.23 4.83 6 0.98 0.000y 3.80 5.86 100.0

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year-nd oc

572 Sant'Anna et alFig 5. A and D, Presurgical photographs of a 6-and C and F, follow-up treatment frontal facial aas open bite on the affected side, crossbite on thecontralateral side, and on occasion anterior cross-bite.24,25 These consequences of mandibular unilateraldistraction require orthodontic treatment over a longperiod of time. Postoperative orthodontic managementcan be difcult in young patients because ofchallenging mechanics and limited cooperation levels.

In this study, combined maxillary and mandibulardistractions were performed to correct the bimaxillarydeformity in patients with HFM as initially suggestedby Molina et al.19 A complete LeFort I was done simul-taneously with a complete horizontal ramus osteotomyon the affected side, placement of a semiburied distrac-tion device with a vertical vector, and wire intermaxillaryxation.19,21 External distractors were not used for ourpatients, since there are some inherent problems withthem. These include facial scars and the tendency forthe external xation pins to loosen. Loose pins preventthe required long-term retention needed to ensureconsolidation of the new regenerate and stability ofthe newly elongated ramus. Early removal of the externaldistractor permits muscle and soft tissue forces to act onthe newly created bone and may lead to relapse. Thisproblem is reduced by the ability to keep internal distrac-tors in place for a prolonged period. This approach

transitional dentition stage (D and E) and no orthododistraction the asymmetry was improved and the infyear follow-up the cant of the occlusal plane and the cside.

May 2015 Vol 147 Issue 5 Americanold boy with left HFM; B and E, after distraction;clusion photographs at age 16 years. Note theprotects the newly created bone and allows the soft tis-sues to adjust to the new length. Although consolidationof the regenerate is usually advanced after 6 to 8 weeks,it continues with additional remodeling.26 In this sam-ple, the devices were left longer (6 months) to accommo-date the patients0 school schedules.

The simultaneous distractions of the maxilla and themandible are designed to correct the vertical and hori-zontal occlusal and chin asymmetries. However, thesefail to correct, if present, an orbitozygomatic defor-mity.14,27 In our patients, all horizontal planesimproved, but of the midline structures only the mentaldeviation from the vertical was statistically signicant.This is explained by the fact that the structures closerto the osteotomynasal septum and maxillaryincisorsdid not change as much because they werecloser to the center of rotation of the maxilloman-dibular complex. The maxilla pivoted around thesurgical wire hinge, located on the unaffected side ofthe LeFort I osteotomy, thus limiting the lateraldisplacement of the hinge wire side of the maxillatoward the unaffected side. However, verticallengthening of the maxilla and the mandible on theaffected side resulted in a signicant rotation of thechin toward the facial midline or the unaffected side.

ntic appliances during distraction. A year aftererior midline was overcorrected, but at the 10-hin point had moved back toward to the affected

Journal of Orthodontics and Dentofacial Orthopedics

Sant'Anna et al 573Combined unilateral vertical maxillary and mandib-ular distractions corrected the cant of the occlusal planeand the chin deviation. The desired complete correctionof the facial asymmetry, especially in the gonial region,was not fully accomplished, even though the changeswere statistically signicant (P 5 0.035). This was notsurprising, since it is geometrically impossible to producemandibular symmetry with a unilateral mandibular

Fig 6. A, Predistraction; B, postdistraction; and C, 10the patient shown in Figure 5. Note the initial cant of thviation of the chin point to the ipsilateral side (A). Afimproved, and the chin point was centered. However,ened and the chin point had deviated to the affected

Fig 7. A,Presurgical frontal facial photographs of a 14and C, posttreatment frontal facial photographs at agfacial symmetry.

American Journal of Orthodontics and Dentofacial Orthopeddistraction in a bone with a multidimensional deformity.It is likely that these patients will require additional sur-gical interventions to further improve their residualasymmetry.28

Facial asymmetry in patients with HFM results fromshortness of the skeleton and hypoplastic soft tissues.The frontal photographic analyses showed that the nasalplane reached a better position related to the horizontal

-year follow-up AP cephalometric radiographs ofe nasal, occlusal, and gonial planes and the de-ter distraction (B), the cant of the 3 planes wasat 10-year follow-up (C), the 3 planes had wors-side.

-year-old boywith left HFM;B, during distraction;e 18 years 6 months. Note the improvement of

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574 Sant'Anna et alline (P5 0.014), the labial commissure leveled, the chinposition moved to the unaffected side (P 5 0.000), andthe mandibular border contour improved but did notachieve full correction. The lack of soft tissues andseverely hypoplastic muscles of mastication makecorrection of HFM facial asymmetry a difcult chal-lenge.29 The distraction process did not augment thelateral bulk of the gonial angle and the overlyingmusclesof mastication. Although the central aspect of the facewas closer to the midline, the appearance of the facewas attened on the affected side, thus compromisingoverall facial symmetry. To minimize the residual facialasymmetry, a series of secondary surgical interventionsis usually necessary. Microvascular or free dermis-fatgrafts can produce excellent results to restore the de-cient soft tissue facial volume.30,31

There is much debate on the timing of surgery inpatients with HFM, for either growing or nongrowingpatients. The introduction of distraction has added tothe confusion. The debate results from different under-standings of how a child with HFM grows. The authors

Fig 8. Occlusion photographs of the patient shown intion; and G-I, after treatment. Note the orthodontic appintermaxillary xation using the orthodontic applianceafter distraction and orthodontic treatment.

May 2015 Vol 147 Issue 5 Americanof 1 study recommended early intervention to preventthe progression of the mandibular and maxillary defor-mities in growing children.9 It is based on the premisethat if the deformity is left untreated, it will worsenover time. The second approach delays intervention untilthe completion of growth. It is based on the premise thatthe deformity, if left untreated, remains relatively stableover time.12,13,32 The severity of HFM varies widely, andthe functional impairments (airway, mastication, andspeech) should dictate the timing of the surgicalintervention. Patients with respiratory distress, andfeeding and speech issues are candidates for earlyinterventions. However, the parents need to be fullyaware that additional corrective skeletal and soft tissueprocedures will become necessary during lateadolescence to fully address the facial asymmetry andfunctional impairments.

To date, there is no evidence supporting the effec-tiveness of early mandibular osteodistraction in patientswith HFM.14 In our study, 4 patients had surgery in theearly mixed dentition to minimize the deformity. Surgery

Figure 7: A-C, presurgical; D-F, during distrac-liances during distraction after initial alignment,s, and excellent facial symmetry and occlusion

Journal of Orthodontics and Dentofacial Orthopedics

Sant'Anna et al 575was performed with full awareness by the parents that asthe child reaches skeletal maturity, more surgical proce-dures would be required.14,33 Although we observed

Fig 10. Occlusal photographs of a 16-year-old boy witandD, after orthodontic alignment. Note the asymmetrment with the decreased distance of the affected side tafter treatment (D), with improved symmetry. Congrucomes with bimaxillary unilateral vertical distraction.

Fig 9. A, Predistraction;B, postdistraction; andC, 4.5the patient shown in Figure 7. Note the initial cant of thviation of the chin point to the ipsilateral side (A). Afimproved, and the chin point was centered. Note theand chin position after distraction and at 4.5-year follo

American Journal of Orthodontics and Dentofacial Orthopedpartial improvements in facial asymmetry, control ofthe occlusion was challenging because the childrenwere in the transitional dentition stage, and also

hHFM:A andC, before orthodontic alignment;By of themandibular arch before orthodontic treat-o themidline (arrows). The arch was well alignedent and symmetrical arches allow for better out-

-year follow-up AP cephalometric radiographs ofe nasal, occlusal, and gonial planes and the de-ter distraction (B), the cant of the 3 planes wasincrease in ramus height, stability of all planes,w-up (C).

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576 Sant'Anna et albecause of their lack of compliance with the elastics andthe limitations of the appliances designed fortransitional dentitions (Figs 5 and 6).

On the other hand, the most successful cases treatedin this small series were the adolescent patients with fullpermanent dentition, with xed orthodontic appliancesplaced to align and level the arches before the bimaxil-lary distraction. No older patient had a secondary ipsilat-eral open bite or a contralateral crossbite. Postoperativeocclusal relationships were close to ideal after the bi-maxillary distraction procedure, and the patientsrequired only routine orthodontics to complete treat-ment during a 6- to 12-month postoperative period;they have remained stable after the surgical and ortho-dontic treatments (Figs 7-9).

The younger patients in our sample will require addi-tional interventions such as additional distraction,double-jaw orthognathic surgery, genioplasty, and softtissue augmentation.

Case selection for a determined surgical procedure iscritical. From our experience, we suggest that patientswith clinically signicant occlusal plane discrepancies,with congruent maxillary and mandibular arch formswhen adequate occlusal interdigitation can be achieved,with minor AP maxillomandibular discrepancies, andwithout excessive maxillary gingival exposure on the un-affected side are appropriate for bimaxillary distraction.However, patients with excessive maxillary gingival showon the affected side can be managed as described here,but later, the vertical maxillary excess can be correctedby maxillary impaction. Maxillary impaction is themost stable procedure in orthognathic surgery.34 Pa-tients with mandibular dentoalveolar arch asymmetrywith a skewed arch should be rst aligned with ortho-dontic treatment before proceeding with bimaxillarydistraction (Fig 10). In patients in the permanent denti-tion with well-aligned arches, xed orthodontic appli-ances are used for intermaxillary xation, comfort(avoiding arch bars), postoperative elastic therapy, andnishing orthodontic occlusal details.

As with many clinical distraction studies, our smallsample size makes it difcult to draw denitive conclu-sions. Series from other authors had similar35 or evensmaller sample sizes8,11,17,31,36-38 to study the effectsof distraction in HFM. The relatively rare incidence ofHFM and the number of patients who t the criteriafor bimaxillary distraction result in limited experiencein the various treatment centers. The challenge forobtaining enough randomized subjects motivated thedevelopment of the National Dental Practice-BasedResearch Network.39 The aim of this initiative is to build

an investigative union of practicing dentists and aca-demic scientists collaborating to rene dental care.

May 2015 Vol 147 Issue 5 AmericanTherefore, intercenter collaborative studies are necessaryto eventually develop a consensus for an effective proto-col to treat patients with HFM.

In this study, skeletal and soft tissue changes after bi-maxillary distraction osteogenesis were measured withAP cephalometric radiographs and frontal facial photo-graphs. Technological advances in 3-dimensional photo-grammetry and radiologic scanning techniques will allowimproved evaluation of outcomes.8,40 The use of 3-dimensional virtual surgical planning and CAD/CAMgenerated splints and surgical guides will assist inselecting the best surgical interventions for a particularcondition and can assist surgeons with accuratesurgical execution, thus improving outcomes.41-45

CONCLUSIONS

Simultaneous maxillary and mandibular distractionimproved facial balance and symmetry in all patientswith HFM. Patients in the permanent dentition withxed appliance orthodontic treatment and well-aligned dental arches responded better to this approachthan did younger patients. The severity of the skeletaland soft tissue deciencies may dictate the need foradditional surgery such as orthognathic surgery, genio-plasty, and soft tissue enhancement procedures toobtain improved facial balance and symmetry.

ACKNOWLEDGMENT

We thank Daniel Ranjbar, Lawrence, Kansas, for hisexpert orthodontic support in the treatment of thepatient shown in Figures 4, 7, and 8.

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Combined maxillary and mandibular distraction osteogenesis in patients with hemifacial microsomiaMaterial and methodsStatistical analysis

ResultsDiscussionConclusionsAcknowledgmentReferences