ORIGINAL ARTICLE
Combined maxillary and mandibular distraction osteogenesis in patients with hemifacial microsomia rgia W. T. Lau,b Mariana Marquezan,c Mo ^ nica Tirre de Souza Arau jo,a Eduardo Franzotti Sant'Anna,a Geo d d John W. Polley, and Alvaro A. Figueroa Rio de Janeiro, Brazil, and Chicago, Ill
Introduction: Hemifacial microsomia is a deformity of variable expressivity with unilateral hypoplasia of the mandible and the ear. In this study, we evaluated skeletal soft tissue changes after bimaxillary unilateral vertical distraction. Methods: Eight patients (4 preadolescents 4 adolescents) each with a grade II mandibular deformity underwent a LeFort I osteotomy and an ipsilateral horizontal mandibular ramus osteotomy. A semiburied distraction device was placed over the ramus, and intermaxillary fixation was applied. Anteroposterior cephalometric and frontal photographic analyses were conducted before and after distraction. Statistics were used to analyze the preoperative and postoperative changes. Results: Cephalometrically, the nasal floor and the occlusal and gonial plane angles decreased. The ratios of affected-unaffected ramus and gonial angle heights improved by 15% and 20%, respectively. The position of menton moved toward the midline. The photographic analysis showed a decrease of the nasal and commissure plane angles, and the chin moved to the unaffected side. The parallelism between the horizontal skeletal and soft tissue planes improved, with an increase in the affected side ramus height and correction of the chin point toward the midline. Conclusions: Simultaneous maxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentition with fixed orthodontic appliances and well-aligned dental arches responded well to this intervention. (Am J Orthod Dentofacial Orthop 2015;147:566-77)
H
emifacial microsomia (HFM) is the best known branchial arch syndrome1-3 and the second most common craniofacial birth defect after
a Associate professor, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly, postdoctoral fellow, Department of Anatomy and Rush Craniofacial Center, Rush University Medical Center, Chicago, Ill. b PhD student, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly, postdoctoral fellow, Department of Anatomy and Rush Craniofacial Center, Rush University Medical Center, Chicago, Ill. c Postdoctoral fellow, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro; Brazilian Army dentist, Santa Maria, Rio de Janeiro, Brazil. d Codirector, Craniofacial Center, Department of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, Ill. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Eduardo Franzotti Sant0 Anna and Georgia W.T. Lau are recipients of scholarships from Coordenac¸~ao de Aperfeic¸oamento de Pessoal de Nıvel Superior (CAPES), and Eduardo Franzotti Sant0 Anna is recipient of grants n. E-26/171.246/2006 and n. E-26/111.647/2010 from Fundac¸~ao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Brazil. Address correspondence to: Alvaro A. Figueroa, Craniofacial Center, Rush University Medical Center, 1725 W Harrison St, Suite 425, Professional Bldg I, Chicago, IL 60612; e-mail, [email protected]. Submitted, April 2014; revised and accepted, December 2014. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.12.027
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cleft lip and palate.4-6 It occurs in 1:35005 to 1:56006 live births. The term HFM refers to an asymmetric congenital condition of variable expressivity affecting primarily aural, oral, and mandibular development. HFM can be part of a broader and variable phenotypic spectrum known as oculoauriculovertebral dysplasia and always involves mandibular and ear malformations, but its severity varies.7,8 The mandibular deficiency usually is associated with microtia, macrostomia, and craniomaxillofacial asymmetry on the affected side. The maxilla, temporal bone, and orbit are also affected as a result of the primary malformation and not secondarily affected by the mandibular hypoplasia, as suggested by some.6 In addition to the skeletal components, neural, muscular, and soft tissues are also affected. The mandibular deformity in HFM was classified by Pruzansky2 in 1969. In his classification, a grade I mandibular deformity consists of a normally shaped but small mandible. Grade II is a small and abnormally shaped mandibular ramus. In grade III, the mandibular deformity is characterized by absence of the mandibular ramus including the temporomandibular joint. The treatment of HFM is centered on the mandibular deformity, but surgical timing is still controversial. The
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reason for this controversy relates to what clinicians believe is the facial growth potential in patients with HFM. Those who support early reconstruction, before skeletal maturity, assume that the mandibular skeletal asymmetry will worsen with time, and that early reconstruction will prevent secondary growth deformities.5,9-11 However, studies have found that the growth of the mandible on the affected side parallels that of the unaffected side, with the degree of asymmetry remaining relatively constant throughout craniofacial development.12-14 Another concern is the psychological adjustment problems caused by differences in facial appearance.15,16 Some clinicians consider that the surgery should be done earlier to prevent social adjustment problems. Others, who prefer to wait for the completion of growth, believe that expectations of reconstructive surgery can cause disillusionment when performed too early, because the patient will still grow asymmetrically and additional surgery will be required. The critical step in achieving better facial skeletal harmony is to restore maxillary and mandibular symmetry. Facial asymmetry is a main indication for orthognathic surgery. Traditionally, skeletal hypoplastic malformations are corrected with segment repositioning with autogenous bone grafts to increase the volume and size.17 Recently, in patients with HFM, distraction osteogenesis has been used for correcting mandibular asymmetry.8,18 Mandibular elongation by gradual distraction is mainly indicated in HFM patients with mandibular deformities grades I and II.19 Since HFM primarily affects not only the mandible but also the maxilla and the orbit, clinicians have suggested simultaneous maxillary and mandibular interventions to correct these asymmetries with a single procedure.19-21 The purpose of this study was to assess skeletal and soft tissue changes after simultaneous maxillary and mandibular distractions in patients with HFM. MATERIAL AND METHODS
Eight patients with HFM grade II mandibular deformity and maxillary asymmetry with a mean age of 13 years 2 months underwent combined maxillary and mandibular distractions.3 The surgical procedures were done under general anesthesia with nasotracheal intubation. A complete horizontal LeFort I osteotomy was performed. In contrast to the original method of Ortiz Monasterio et al,19 the pterygomaxillary junction was freed with a curved chisel on both sides, not only on the affected side. The unaffected maxillary side LeFort I osteotomy was loosely secured with 1 surgical wire placed above
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the maxillary first and second permanent molars. This wire acted as a hinge and pivot point where the maxillomandibular complex was expected to rotate toward the unaffected side (Fig 1). The ascending ramus was exposed along its anterior border behind the last molar and extended to the gonial angle and the surrounding area. The orientation of the osteotomy and the position of the distractor device determined the vector of distraction. A semiburied distraction device (Z€ urich II Distraction System; KLS Martin, Jacksonville, Fla) was positioned over the ramus in the planned direction (usually parallel to the long axis of the ramus) and fixed with self-tapping screws to secure the foot plates above and below the initially incomplete horizontal ramus osteotomy. The activating arm, from the semiburied device, was placed externally through a small incision below the mandibular angle. The osteotomy was completed and verified by opening the distractor. Before closure, the device was deactivated. The incision was closed, and rigid intermaxillary fixation with surgical wires was applied. Younger patients in the mixed dentition had custom-banded (maxillary and mandibular first permanent molars) arch bars with soldered hooks secured with circumdental wires for additional support during intermaxillary wire fixation and elastic therapy. In the adolescent patients, the orthodontic appliances were used for presurgical alignment and intermaxillary wire fixation and postoperative elastic therapy. The extent of the required bone elongation and the vector of the distraction were determined by the severity of the ipsilateral mandibular deformity, the shape of the contralateral or unaffected mandibular ramus, and the transverse cant of the occlusal plane. After 7 days (latency period), the device was lengthened by 0.5 mm twice a day, for an average of 22 consecutive days. In younger patients, vertical elongation of over 15 mm was usually not required; therefore, a single 15-mm distractor was able to correct the occlusal plane discrepancy. In the adolescent patients who required more than 15 mm of vertical distraction, we preplanned 2 consecutive surgical procedures; after full activation of the first 15-mm distractor, it was removed, and another distractor of 30 mm was placed to complete the required vertical distraction. This is a required step, since the bone available to fixate the device above and below the planned osteotomy over the ramus is only sufficient to accommodate a distractor of limited length (usually 15 mm). After the initial distraction, a longer distractor can be placed. This device is partially opened before placement to clear the newly generated bone. Another reason why in certain patients it is necessary to use 2 consecutive devices relates to the fact that the initial
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Fig 1. Schematic representation of bimaxillary unilateral vertical distraction surgical plan. A, Complete maxillary LeFort I (dashed line), unilateral horizontal ramus osteotomy; mandibular buried single-vector distractor; intermaxillary wire fixation (dotted line); single wire acting as a hinge (circle, contralateral side); vertical and curved arrows indicate the expected direction of the maxillary and mandibular movements after distraction. B, Expected vertical bone formation between osteotomies, downward and medial rotation of the maxilla and mandible to the contralateral side with leveling of the occlusal plane and restoration of symmetry. (Reproduced with permission from Figueroa and Polley.21)
placement is such that true vertical elongation is not obtained. The placement of the device has mainly a vertical component with a forward and medial vector because of the shape of the hypoplastic ramus and the contralateral ramus that needs to be emulated to correct as much as possible not only the size but also the form of the ramus. The placement of the distractor in this manner results in an effective loss of vertical length. Semiburied distractors are rigid and true to their length, but as explained above, the skeletal change is less than the true expression of the distractor; therefore, the activation to skeletal change ratio is not 1:1. The goal of bimaxillary distraction is mainly to obtain a level occlusal plane and not perfect symmetry of the gonial angles. The reason is that the vertical discrepancy is usually greater at the gonial angles, and if they are leveled, the occlusal plane will be canted downward on the affected side. The gonial angle asymmetry can be addressed secondarily with bone grafting combined with other required procedures—eg, genioplasty or soft tissue augmentation—to further improve appearance. Activation of the mandibular distractor resulted in vertical elongation of the affected ramus and medial displacement of both the maxillary and mandibular dentitions toward the unaffected side. This was possible because the patients had a complete affected side horizontal ramus osteotomy and a complete LeFort I
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osteotomy. In addition, they were placed in intermaxillary wire fixation to move the maxilla, the mandible, and the dentition as a unit. The patient's preoperative occlusion was preserved through intermaxillary wire fixation during distraction. After distraction, a consolidation period with wire intermaxillary fixation was completed (4 weeks for the younger patients and up to 6 weeks for the adolescent patients). After this period, the wires were replaced with 6-oz, ¼-in orthodontic elastics for the next 3 months. The patients were placed on a liquid diet during the intermaxillary fixation period and a soft diet for 4 to 6 weeks after the wires were removed. Orthodontic treatment was continued in the adolescent patients for 6 to 8 weeks after the wire fixation was removed. In the younger patients, the fixation appliances were removed after 2 to 3 months of elastic therapy. The distraction device was left in place for 6 months and removed in the operating room under general anesthesia. All patients had anteroposterior (AP) cephalometric radiographs and clinical frontal photographs taken before and after distraction in a standard manner. Skeletal and soft tissue facial asymmetries were respectively measured with AP cephalometric and soft tissue photographic frontal analysis. Radiographs and photographs were hand traced by the same investigator (E.F.S.). Each measurement was repeated 3 times, and the mean was recorded for data comparison. There was no statistical difference
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Table I. Description of the cephalometric AP analysis for the vertical and horizontal measurements Measurement Definition Vertical angle measurements HL-Co0 Co Angle between the HL and the bicondylar plane HL-NF0 NF
Angle between the HL and the nasal floor plane
HL-J0 J
Angle between the HL and the maxillary jugal points
HL-OCP
Angle between the HL and the occlusal plane
HL-Go0 Go
Angle between the HL and the gonial plane
Landmark Condylion (Co), external lateral marginal portion of the condylar head Nasal floor (NF), most inferior point on inside surface of the bony nasal cavity Jugal process (J), bilateral points on the jugal process of the maxilla at a crossing with the tuberosity of the maxilla Occlusal plane (OCP), horizontal plane passing through the molar and the incisors Gonion (Go), most lateral and inferior point of the mandibular angle
Horizontal angle measurements VL-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
Incision superior frontale (isf), midpoint between the maxillary central incisor at the level of the incisal edges Menton (Me), point on the inferior border of the symphysis directly inferior to the mental protuberance Anterior nasal spine (ANS), tip of the ANS below the nasal cavity and above the hard palate Top of the nasal septum (Tns), the highest point on the superior aspect of the nasal septum
Fig 2. Cephalometric analysis of vertical and horizontal changes. A, Horizontal planes relative to the HL and VL references used for analysis: 1, HL-Co0 Co bicondylar plane; 2, HL HL-NF0 NF nasal floor plane; 3, J0 J maxillary jugal plane; 4, HL-occlusal plane; 5, HL-Go0 Go gonial plane. B, Vertical planes used for analysis: 1, VL-isf superior midline; 2, VL-Me mental line; 3, Tns-ANS nasal septum deviation to the VL.
between the 3 measurements as determined by the Dahlberg22 double determination method. The measurements from the AP cephalograms are given in Table I. Two reference lines were traced (Fig 2) and used to make vertical and horizontal measurements: a horizontal line (HL), the line connecting the right and left latero-orbitale points, and a vertical line (VL), the line perpendicular to the HL through the center of crista galli (most constricted point of the projection of the perpendicular lamina of the ethmoid).
The gonial height ratio (HL-Go0 /HL-Go) and the ramus height ratio (CoGo0 /CoGo) were calculated from the AP cephalograms to compare the affected vs the unaffected sides. HL-Go0 /HL-Go is the ratio between the linear perpendicular distance from the horizontal reference line to the affected Go0 point, and the linear perpendicular distance from the horizontal reference line to the unaffected Go point. Co0 Go0 /CoGo is the ratio between the linear perpendicular distance from the affected Co0 point to the affected Go0 point, and the linear
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Fig 3. Cephalometric analysis of the ratio of affected vs unaffected gonial height (HL-Go0 /HL-Go) and ramus height (Co0 -Go0 /Co-Go).
perpendicular distance from the unaffected Co point to the unaffected Go point (Fig 3). In the photographic facial analysis, we used 3 bilateral soft tissue landmarks identified on the frontal photographs: bilateral endocanthion (inner commissure of the eye fissure) and the center point of a line connecting the right and left endocanthions. Two reference lines were traced on the frontal photographs (Fig 4): an HL, the line connecting the right endocanthion to the left endocanthion points; and a VL, the line perpendicular to the HL through the midline of the distance between the right and left endocanthion points. The measurements obtained from the frontal photographs are shown in Table II. Statistical analysis
Paired t tests were used to examine the difference between the preoperative (T1) and postoperative (T2, 6 months after surgery) measurements using the Statistical Package for Social Sciences software (version15.0; SPSS, Chicago, Ill). The power of the paired t test was calculated for each variable considering a sample size of 8 and an a of 0.05, using the free software power and sample size calculator (version 3.1.2; Statistical Solutions, Boston, Mass). RESULTS
The results of the AP cephalometric analysis demonstrated vertical improvement in all patients as seen by statistically significant decreases relative to the HL of the nasal floor angle (P 5 0.004), the maxillary jugal plane
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Fig 4. Planes used in the photographic analysis to evaluate vertical and horizontal facial changes relative to the HL and VL reference lines: 1, HL-sbal0 sbal nasal base plane; 2, HL-ch0 ch labial commissure plane; 3, VL-Pog vertical line chin point.
angle (P 5 0.008), the occlusal plane angle (P 5 0.003), and the gonial plane angle (P 5 0.035). Of the horizontal changes, only the menton to the VL measurement (P 5 0.004) was statistically significant (Table III). The ratio of the affected-unaffected gonial height (HL-Go0 /HL-Go) significantly improved by 20% from 65.85% to 86.61% (P 5 0.027). Ramus height (Co0 Go0 /CoGo) also significantly improved by almost 15% from 78.12% to 93.06% (P 5 0.042) (Table III). The findings demonstrated parallelism among the horizontal planes, vertical elongation of the affected side ramus height, and improvement of the midline deviation measurements. These were favorable changes toward restoring symmetry. The facial photographic analysis (Table IV) demonstrated significant changes, with the nasal plane improving by 3.00 (P 5 0.014), and the chin position changing toward the unaffected side by 4.83 (P 5 0.000), thus improving the midline symmetry, but without reaching full correction. Although not statistically significant, the labial commissure plane improved by 2.3 . The power of the t test (ie, the probability of correctly rejecting the null hypothesis) is included in Tables III and IV. Most variables with statistically significant differences between T1 and T2 (6 of 9) had an over 90% power for the t tests.
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Table II. Description of photographic facial analysis for the vertical and horizontal measurements Measurement Vertical angle measurements HL-sbal0 sbal (nasal base angle plane) HL-ch0 ch (labial commissure angle plane) Horizontal angle measurement VL-Pog (chin point)
Definition
Landmark
Angle between the HL and the nasal base plane Angle between the HL and the labial commissure plane, and 1 horizontal angle measurement
Subalare (sbal), lower limit of each alar base Cheilion (ch) point at each labial commissure
Angle between the VL and the chin point
Pogonion (Pog), most anterior midpoint of the chin
Table III. Vertical and horizontal angular measurements and ratios from anteroposterior cephalometric radiographs
Measurement Bicondylar plane (HL-Co0 -Co) ( ) Nasal floor plane (HL-NF0 NF) ( ) Maxillary jugal plane (HL-J0 J) ( ) Occlusal plane (HL-OCP) ( ) Gonial plane (HL-Go0 Go) ( ) Superior midline (VL-isf) ( ) Mental line (VL-Me) ( ) Nasal septum deviation (Tns-ANS) ( ) Gonial height (HL-Go0 /HL-Go) (%) Ramus height (Co0 -Go0 /Co-Go) (%)
T1 mean 6 SD 3.42 6 2.07 14.28 6 6.36 11.85 6 6.76 12.71 6 5.85 12.42 6 7.18 5.71 6 4.95 7.00 6 7.58 14.71 6 6.36 78.12 6 14.45 65.85 6 16.01
T2 mean 6 SD 2.14 6 1.46 8.00 6 6.55 3.00 6 4.12 4.42 6 4.07 4.00 6 5.13 3.85 6 5.08 3.4 6 7.05 11.14 6 6.36 93.06 6 9.32 86.61 6 12.35
Difference T1 T2 mean 6 SD 1.28 6 1.70 6.28 6 3.72 8.85 6 6.03 8.28 6 4.46 8.42 6 8.24 1.85 6 3.18 3.6 6 2.50 3.57 6 4.03 14.93 6 13.59 20.76 6 21.37
95% CI of the difference P value 0.093 0.004y 0.008y 0.003y 0.035* 0.174 0.033* 0.058 0.027* 0.042*
Lower 0.29 2.83 2.28 4.15 0.80 1.08 0.48 0.16 2.36 0.99
Upper 2.86 9.73 3.27 12.41 16.05 4.80 6.71 7.30 27.50 40.53
Power of paired t test (%) 41.2 97.7 94.2 98.8 69.3 25.0 93.5 55.5 76.0 64.4
0 Affected side. *P \ 0.05; yP \ 0.01.
Table IV. Vertical and horizontal angular measurements from frontal photographs Difference T1T2 Measurement T1 mean 6 SD T2 mean 6 SD mean 6 SD P value Nasal base angle plane (HL-sbal0 sbal) ( ) 7.50 6 5.91 4.25 6 5.25 3.00 6 2.00 0.014* Labial commissure angle plane (HL-ch0 ch) ( ) 9.75 6 4.99 6.75 6 6.89 2.33 6 3.14 0.128 8.75 6 6.23 3.75 6 6.23 4.83 6 0.98 0.000y Vertical line-chin point angle (VL-pog) ( )
95% CI of the difference Lower 0.90 0.96 3.80
Upper 5.09 5.62 5.86
Power of paired t test (%) 94.9 40.0 100.0
0
Affected side. *P \ 0.05; yP \ 0.01.
DISCUSSION
Reconstruction of an asymmetric mandible associated with a soft tissue deficiency is one of the most challenging problems in patients with HFM. Numerous surgical procedures have been advocated to correct facial asymmetry in these patients, including costochondral grafts, mandibular osteotomies combined with bone grafts, and maxillary osteotomies, done at an early age or in late adolescence.6,9,18 The results can be unpredictable because of undesirable resorption of the graft, leading to decreases in volume and strength of the reconstructed area. Furthermore, these procedures can cause significant morbidity at the donor site. Conventional orthognathic surgery, such as maxillary impaction on the unaffected side, is usually performed
with mandibular osteotomies.17 A large movement has a high risk for relapse because of the soft tissue deficiency of HFM. Recently, a complete fossa, condyle, and ramus reconstruction with a prosthetic replacement has been reported in adolescent patients with HFM with severe mandibular deformities.23 Distraction osteogenesis has provided an alternative in the treatment of craniomaxillofacial deformities.18 Its success is related to the fact that it uses the body0 s own healing mechanisms to produce new bone and elongate the soft tissues. This diminishes the need for autografts, thus decreasing morbidity. Mandibular elongation by gradual distraction can be done at any age.19 However, acute changes in mandibular shape result in postoperative alterations in dental occlusion, such
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Fig 5. A and D, Presurgical photographs of a 6-year-old boy with left HFM; B and E, after distraction; and C and F, follow-up treatment frontal facial and occlusion photographs at age 16 years. Note the transitional dentition stage (D and E) and no orthodontic appliances during distraction. A year after distraction the asymmetry was improved and the inferior midline was overcorrected, but at the 10year follow-up the cant of the occlusal plane and the chin point had moved back toward to the affected side.
as open bite on the affected side, crossbite on the contralateral side, and on occasion anterior crossbite.24,25 These consequences of mandibular unilateral distraction require orthodontic treatment over a long period of time. Postoperative orthodontic management can be difficult in young patients because of challenging mechanics and limited cooperation levels. In this study, combined maxillary and mandibular distractions were performed to correct the bimaxillary deformity in patients with HFM as initially suggested by Molina et al.19 A complete LeFort I was done simultaneously with a complete horizontal ramus osteotomy on the affected side, placement of a semiburied distraction device with a vertical vector, and wire intermaxillary fixation.19,21 External distractors were not used for our patients, since there are some inherent problems with them. These include facial scars and the tendency for the external fixation pins to loosen. Loose pins prevent the required long-term retention needed to ensure consolidation of the new regenerate and stability of the newly elongated ramus. Early removal of the external distractor permits muscle and soft tissue forces to act on the newly created bone and may lead to relapse. This problem is reduced by the ability to keep internal distractors in place for a prolonged period. This approach
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protects the newly created bone and allows the soft tissues to adjust to the new length. Although consolidation of the regenerate is usually advanced after 6 to 8 weeks, it continues with additional remodeling.26 In this sample, the devices were left longer (6 months) to accommodate the patients0 school schedules. The simultaneous distractions of the maxilla and the mandible are designed to correct the vertical and horizontal occlusal and chin asymmetries. However, these fail to correct, if present, an orbitozygomatic deformity.14,27 In our patients, all horizontal planes improved, but of the midline structures only the mental deviation from the vertical was statistically significant. This is explained by the fact that the structures closer to the osteotomy—nasal septum and maxillary incisors—did not change as much because they were closer to the center of rotation of the maxillomandibular complex. The maxilla pivoted around the surgical wire hinge, located on the unaffected side of the LeFort I osteotomy, thus limiting the lateral displacement of the hinge wire side of the maxilla toward the unaffected side. However, vertical lengthening of the maxilla and the mandible on the affected side resulted in a significant rotation of the chin toward the facial midline or the unaffected side.
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Fig 6. A, Predistraction; B, postdistraction; and C, 10-year follow-up AP cephalometric radiographs of the patient shown in Figure 5. Note the initial cant of the nasal, occlusal, and gonial planes and the deviation of the chin point to the ipsilateral side (A). After distraction (B), the cant of the 3 planes was improved, and the chin point was centered. However, at 10-year follow-up (C), the 3 planes had worsened and the chin point had deviated to the affected side.
Fig 7. A, Presurgical frontal facial photographs of a 14-year-old boy with left HFM; B, during distraction; and C, posttreatment frontal facial photographs at age 18 years 6 months. Note the improvement of facial symmetry.
Combined unilateral vertical maxillary and mandibular distractions corrected the cant of the occlusal plane and the chin deviation. The desired complete correction of the facial asymmetry, especially in the gonial region, was not fully accomplished, even though the changes were statistically significant (P 5 0.035). This was not surprising, since it is geometrically impossible to produce mandibular symmetry with a unilateral mandibular
distraction in a bone with a multidimensional deformity. It is likely that these patients will require additional surgical interventions to further improve their residual asymmetry.28 Facial asymmetry in patients with HFM results from shortness of the skeleton and hypoplastic soft tissues. The frontal photographic analyses showed that the nasal plane reached a better position related to the horizontal
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Fig 8. Occlusion photographs of the patient shown in Figure 7: A-C, presurgical; D-F, during distraction; and G-I, after treatment. Note the orthodontic appliances during distraction after initial alignment, intermaxillary fixation using the orthodontic appliances, and excellent facial symmetry and occlusion after distraction and orthodontic treatment.
line (P 5 0.014), the labial commissure leveled, the chin position moved to the unaffected side (P 5 0.000), and the mandibular border contour improved but did not achieve full correction. The lack of soft tissues and severely hypoplastic muscles of mastication make correction of HFM facial asymmetry a difficult challenge.29 The distraction process did not augment the lateral bulk of the gonial angle and the overlying muscles of mastication. Although the central aspect of the face was closer to the midline, the appearance of the face was flattened on the affected side, thus compromising overall facial symmetry. To minimize the residual facial asymmetry, a series of secondary surgical interventions is usually necessary. Microvascular or free dermis-fat grafts can produce excellent results to restore the deficient soft tissue facial volume.30,31 There is much debate on the timing of surgery in patients with HFM, for either growing or nongrowing patients. The introduction of distraction has added to the confusion. The debate results from different understandings of how a child with HFM grows. The authors
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of 1 study recommended early intervention to prevent the progression of the mandibular and maxillary deformities in growing children.9 It is based on the premise that if the deformity is left untreated, it will worsen over time. The second approach delays intervention until the completion of growth. It is based on the premise that the deformity, if left untreated, remains relatively stable over time.12,13,32 The severity of HFM varies widely, and the functional impairments (airway, mastication, and speech) should dictate the timing of the surgical intervention. Patients with respiratory distress, and feeding and speech issues are candidates for early interventions. However, the parents need to be fully aware that additional corrective skeletal and soft tissue procedures will become necessary during late adolescence to fully address the facial asymmetry and functional impairments. To date, there is no evidence supporting the effectiveness of early mandibular osteodistraction in patients with HFM.14 In our study, 4 patients had surgery in the early mixed dentition to minimize the deformity. Surgery
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Fig 9. A, Predistraction; B, postdistraction; and C, 4.5-year follow-up AP cephalometric radiographs of the patient shown in Figure 7. Note the initial cant of the nasal, occlusal, and gonial planes and the deviation of the chin point to the ipsilateral side (A). After distraction (B), the cant of the 3 planes was improved, and the chin point was centered. Note the increase in ramus height, stability of all planes, and chin position after distraction and at 4.5-year follow-up (C).
Fig 10. Occlusal photographs of a 16-year-old boy with HFM: A and C, before orthodontic alignment; B and D, after orthodontic alignment. Note the asymmetry of the mandibular arch before orthodontic treatment with the decreased distance of the affected side to the midline (arrows). The arch was well aligned after treatment (D), with improved symmetry. Congruent and symmetrical arches allow for better outcomes with bimaxillary unilateral vertical distraction.
was performed with full awareness by the parents that as the child reaches skeletal maturity, more surgical procedures would be required.14,33 Although we observed
partial improvements in facial asymmetry, control of the occlusion was challenging because the children were in the transitional dentition stage, and also
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because of their lack of compliance with the elastics and the limitations of the appliances designed for transitional dentitions (Figs 5 and 6). On the other hand, the most successful cases treated in this small series were the adolescent patients with full permanent dentition, with fixed orthodontic appliances placed to align and level the arches before the bimaxillary distraction. No older patient had a secondary ipsilateral open bite or a contralateral crossbite. Postoperative occlusal relationships were close to ideal after the bimaxillary distraction procedure, and the patients required only routine orthodontics to complete treatment during a 6- to 12-month postoperative period; they have remained stable after the surgical and orthodontic treatments (Figs 7-9). The younger patients in our sample will require additional interventions such as additional distraction, double-jaw orthognathic surgery, genioplasty, and soft tissue augmentation. Case selection for a determined surgical procedure is critical. From our experience, we suggest that patients with clinically significant occlusal plane discrepancies, with congruent maxillary and mandibular arch forms when adequate occlusal interdigitation can be achieved, with minor AP maxillomandibular discrepancies, and without excessive maxillary gingival exposure on the unaffected side are appropriate for bimaxillary distraction. However, patients with excessive maxillary gingival show on the affected side can be managed as described here, but later, the vertical maxillary excess can be corrected by maxillary impaction. Maxillary impaction is the most stable procedure in orthognathic surgery.34 Patients with mandibular dentoalveolar arch asymmetry with a skewed arch should be first aligned with orthodontic treatment before proceeding with bimaxillary distraction (Fig 10). In patients in the permanent dentition with well-aligned arches, fixed orthodontic appliances are used for intermaxillary fixation, comfort (avoiding arch bars), postoperative elastic therapy, and finishing orthodontic occlusal details. As with many clinical distraction studies, our small sample size makes it difficult to draw definitive conclusions. Series from other authors had similar35 or even smaller sample sizes8,11,17,31,36-38 to study the effects of distraction in HFM. The relatively rare incidence of HFM and the number of patients who fit the criteria for bimaxillary distraction result in limited experience in the various treatment centers. The challenge for obtaining enough randomized subjects motivated the development of the National Dental Practice-Based Research Network.39 The aim of this initiative is to build an investigative union of practicing dentists and academic scientists collaborating to refine dental care.
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Therefore, intercenter collaborative studies are necessary to eventually develop a consensus for an effective protocol to treat patients with HFM. In this study, skeletal and soft tissue changes after bimaxillary distraction osteogenesis were measured with AP cephalometric radiographs and frontal facial photographs. Technological advances in 3-dimensional photogrammetry and radiologic scanning techniques will allow improved evaluation of outcomes.8,40 The use of 3dimensional virtual surgical planning and CAD/CAM generated splints and surgical guides will assist in selecting the best surgical interventions for a particular condition and can assist surgeons with accurate surgical execution, thus improving outcomes.41-45 CONCLUSIONS
Simultaneous maxillary and mandibular distraction improved facial balance and symmetry in all patients with HFM. Patients in the permanent dentition with fixed appliance orthodontic treatment and wellaligned dental arches responded better to this approach than did younger patients. The severity of the skeletal and soft tissue deficiencies may dictate the need for additional surgery such as orthognathic surgery, genioplasty, and soft tissue enhancement procedures to obtain improved facial balance and symmetry. ACKNOWLEDGMENT
We thank Daniel Ranjbar, Lawrence, Kansas, for his expert orthodontic support in the treatment of the patient shown in Figures 4, 7, and 8. REFERENCES 1. Grabb WC. The first and second branchial arch syndrome. Plast Reconstr Surg 1965;36:485-508. 2. Pruzansky S. Not all dwarfed mandibles are alike. Birth Defects Orig Artic Ser 1969;5:120-9. 3. Figueroa AA, Pruzansky S. The external ear, mandible and other components of hemifacial microsomia. J Maxillofac Surg 1982; 10:200-11. 4. Murray JE, Kaban LB, Mulliken JB. Analysis and treatment of hemifacial microsomia. Plast Reconstr Surg 1984;74:186-99. 5. Kaban LB, Mulliken JB, Murray JE. Three-dimensional approach to analysis and treatment of hemifacial microsomia. Cleft Palate J 1981;18:90-9. 6. Molina F, Ortiz Monasterio F. Mandibular elongation and remodeling by distraction: a farewell to major osteotomies. Plast Reconstr Surg 1995;96:825-40. 7. Gorlin RJ, Cohen MM Jr, Hennekam RCM. Syndromes of the head and neck. 4th ed. New York: Oxford University Press; 2001. 8. Chow A, Lee HF, Trahar M, Kawamoto H, Vastardis H, Ting K. Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a long-term study. Am J Orthod Dentofacial Orthop 2008;134: 724-31.
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9. Kaban LB, Moses MH, Mulliken JB. Surgical correction of hemifacial microsomia in the growing child. Plast Reconstr Surg 1988;82:9-19. 10. Grayson BH, Santiago PE. Treatment planning and vector analysis of mandibular distraction osteogenesis. Atlas Oral Maxillofac Surg Clin North Am 1999;7:1-13. 11. Jansma J, Bierman MW, Becking AG. Intraoral distraction osteogenesis to lengthen the ascending ramus. Experience with seven patients. Br J Oral Maxillofac Surg 2004;42:526-31. 12. Rune B, Selvik G, Sarnas KV, Jacobsson S. Growth in hemifacial microsomia studied with the aid of roentgen stereophotogrammetry and metallic implants. Cleft Palate J 1981;18:128-46. 13. Polley JW, Figueroa AA, Liou EJ, Cohen M. Longitudinal analysis of mandibular asymmetry in hemifacial microsomia. Plast Reconstr Surg 1997;99:328-39. 14. Nagy K, Kuijpers-Jagtman AM, Mommaerts MY. No evidence for long-term effectiveness of early osteodistraction in hemifacial microsomia. Plast Reconstr Surg 2009;124:2061-71. 15. Khetani MA, Collett BR, Speltz ML, Werler MM. Healthrelated quality of life in children with hemifacial microsomia: parent and child perspectives. J Dev Behav Pediatr 2013;34: 661-8. 16. Bemmels H, Biesecker B, Schmidt JL, Krokosky A, Guidotti R, Sutton EJ. Psychological and social factors in undergoing reconstructive surgery among individuals with craniofacial conditions: an exploratory study. Cleft Palate Craniofac J 2013;50:158-67. 17. Yamauchi K, Takahashi T. Maxillary distraction osteogenesis combined with mandibular osteotomy to correct asymmetry of the maxillomandibular complex. Plast Reconstr Surg 2006;118: 39e-45e. 18. McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1-8. 19. Ortiz Monasterio F, Molina F, Andrade L, Rodriguez C, Sainz Arregui J. Simultaneous mandibular and maxillary distraction in hemifacial microsomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 1997;100:852-61. 20. Molina F, Ortiz Monasterio F, de la Paz Aguilar M, Barrera J. Maxillary distraction: aesthetic and functional benefits in cleft lip-palate and prognathic patients during mixed dentition. Plast Reconstr Surg 1998;101:951-63. 21. Figueroa AA, Polley JW. Mandibular distraction osteogenesis. Operative Techniques. Otolaryngol Head Neck Surg 2002;13: 17-28. 22. Dahlberg G. Statistical methods for medical and biological students. New York: Interscience Publications; 1940. 23. Movahed R, Teschke M, Wolford LM. Protocol for concomitant temporomandibular joint custom-fitted total joint reconstruction and orthognathic surgery utilizing computer-assisted surgical simulation. J Oral Maxillofac Surg 2013;71:2123-9. 24. Hanson PR, Melugin MB. Orthodontic management of the patient undergoing mandibular distraction osteogenesis. Semin Orthod 1999;5:25-34. 25. Matsumoto K, Nakanishi H, Koizumi Y, Yamano M, Hashimoto I, Satake S, et al. Occlusal difficulties after simultaneous mandibular and maxillary distraction in an adult case of hemifacial microsomia. J Craniofac Surg 2004;15:464-8. 26. Samchukov M, Cope J, Cherkashin A. Biological basis of new bone formation under the influence of tension stress. In: Craniofacial distraction osteogenesis. St Louis: Mosby; 2001. p. 21-36. 27. Polley JW, Figueroa AA. Distraction osteogenesis: its application in severe mandibular deformities in hemifacial microsomia. J Craniofac Surg 1997;8:422-30.
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28. Molina F. Mandibular distraction: surgical refinements and longterm results. Clin Plast Surg 2004;31:443-62,vi-vii. 29. Huisinga-Fischer CE, Vaandrager JM, Prahl-Andersen B. Longitudinal results of mandibular distraction osteogenesis in hemifacial microsomia. J Craniofac Surg 2003;14:924-33. 30. Inigo F, Rojo P, Ysunza A. Aesthetic treatment of Romberg's disease: experience with 35 cases. Br J Plast Surg 1993;46:194-200. 31. Inigo F, Jimenez-Murat Y, Arroyo O, Fernandez M, Ysunza A. Restoration of facial contour in Romberg's disease and hemifacial microsomia: experience with 118 cases. Microsurgery 2000;20:167-72. 32. Kusnoto B, Figueroa AA, Polley JW. A longitudinal threedimensional evaluation of the growth pattern in hemifacial microsomia treated by mandibular distraction osteogenesis: a preliminary report. J Craniofac Surg 1999;10:480-6. 33. Meazzini MC, Mazzoleni F, Bozzetti A, Brusati R. Comparison of mandibular vertical growth in hemifacial microsomia patients treated with early distraction or not treated: follow up till the completion of growth. J Craniomaxillofac Surg 2012;40:105-11. 34. Proffit WR, Phillips C, Turvey TA. Stability following superior repositioning of the maxilla by LeFort I osteotomy. Am J Orthod Dentofacial Orthop 1987;92:151-61. 35. Cho BC, Shin DP, Park JW, Baik BS. Bimaxillary osteodistraction for the treatment of facial asymmetry in adults. Br J Plast Surg 2001;54:491-8. 36. Tehranchi A, Behnia H. Treatment of mandibular asymmetry by distraction osteogenesis and orthodontics: a report of four cases. Angle Orthod 2000;70:165-74. 37. Marquez IM, Fish LC, Stella JP. Two-year follow-up of distraction osteogenesis: its effect on mandibular ramus height in hemifacial microsomia. Am J Orthod Dentofacial Orthop 2000;117: 130-9. 38. Wolford LM, Bourland TC, Rodrigues D, Perez DE, Limoeiro E. Successful reconstruction of nongrowing hemifacial microsomia patients with unilateral temporomandibular joint total joint prosthesis and orthognathic surgery. J Oral Maxillofac Surg 2012;70:2835-53. 39. Kokich VG. Consider joining the orthodontic practice-based research network. Am J Orthod Dentofacial Orthop 2013; 144:323. 40. Trahar M, Sheffield R, Kawamoto H, Lee HF, Ting K. Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a preliminary report. Am J Orthod Dentofacial Orthop 2003;124:639-50. 41. Gateno J, Xia J, Teichgraeber JF, Rosen A. A new technique for the creation of a computerized composite skull model. J Oral Maxillofac Surg 2003;61:222-7. 42. Xia JJ, Gateno J, Teichgraeber JF, Christensen AM, Lasky RE, Lemoine JJ, et al. Accuracy of the computer-aided surgical simulation (CASS) system in the treatment of patients with complex craniomaxillofacial deformity: a pilot study. J Oral Maxillofac Surg 2007;65:248-54. 43. Xia JJ, Shevchenko L, Gateno J, Teichgraeber JF, Taylor TD, Lasky RE, et al. Outcome study of computer-aided surgical simulation in the treatment of patients with craniomaxillofacial deformities. J Oral Maxillofac Surg 2011;69:2014-24. 44. Polley JW, Figueroa AA. Orthognathic positioning system: intraoperative system to transfer virtual surgical plan to operating field during orthognathic surgery. J Oral Maxillofac Surg 2013;71:911-20. 45. Shibazaki-Yorozuya R, Yamada A, Nagata S, Ueda K, Miller AJ, Maki K. Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with conebeam computed tomography. Am J Orthod Dentofacial Orthop 2014;145:579-94.
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Combined maxillary and mandibular distraction osteogenesis in patients with hemifacial microsomia rgia W. T. Lau,b Mariana Marquezan,c Mo ^ nica Tirre de Souza Arau jo,a Eduardo Franzotti Sant'Anna,a Geo d d John W. Polley, and Alvaro A. Figueroa Rio de Janeiro, Brazil, and Chicago, Ill
Introduction: Hemifacial microsomia is a deformity of variable expressivity with unilateral hypoplasia of the mandible and the ear. In this study, we evaluated skeletal soft tissue changes after bimaxillary unilateral vertical distraction. Methods: Eight patients (4 preadolescents 4 adolescents) each with a grade II mandibular deformity underwent a LeFort I osteotomy and an ipsilateral horizontal mandibular ramus osteotomy. A semiburied distraction device was placed over the ramus, and intermaxillary fixation was applied. Anteroposterior cephalometric and frontal photographic analyses were conducted before and after distraction. Statistics were used to analyze the preoperative and postoperative changes. Results: Cephalometrically, the nasal floor and the occlusal and gonial plane angles decreased. The ratios of affected-unaffected ramus and gonial angle heights improved by 15% and 20%, respectively. The position of menton moved toward the midline. The photographic analysis showed a decrease of the nasal and commissure plane angles, and the chin moved to the unaffected side. The parallelism between the horizontal skeletal and soft tissue planes improved, with an increase in the affected side ramus height and correction of the chin point toward the midline. Conclusions: Simultaneous maxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentition with fixed orthodontic appliances and well-aligned dental arches responded well to this intervention. (Am J Orthod Dentofacial Orthop 2015;147:566-77)
H
emifacial microsomia (HFM) is the best known branchial arch syndrome1-3 and the second most common craniofacial birth defect after
a Associate professor, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly, postdoctoral fellow, Department of Anatomy and Rush Craniofacial Center, Rush University Medical Center, Chicago, Ill. b PhD student, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; formerly, postdoctoral fellow, Department of Anatomy and Rush Craniofacial Center, Rush University Medical Center, Chicago, Ill. c Postdoctoral fellow, Department of Pedodontics and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro; Brazilian Army dentist, Santa Maria, Rio de Janeiro, Brazil. d Codirector, Craniofacial Center, Department of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, Ill. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Eduardo Franzotti Sant0 Anna and Georgia W.T. Lau are recipients of scholarships from Coordenac¸~ao de Aperfeic¸oamento de Pessoal de Nıvel Superior (CAPES), and Eduardo Franzotti Sant0 Anna is recipient of grants n. E-26/171.246/2006 and n. E-26/111.647/2010 from Fundac¸~ao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Brazil. Address correspondence to: Alvaro A. Figueroa, Craniofacial Center, Rush University Medical Center, 1725 W Harrison St, Suite 425, Professional Bldg I, Chicago, IL 60612; e-mail, [email protected]. Submitted, April 2014; revised and accepted, December 2014. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.12.027
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cleft lip and palate.4-6 It occurs in 1:35005 to 1:56006 live births. The term HFM refers to an asymmetric congenital condition of variable expressivity affecting primarily aural, oral, and mandibular development. HFM can be part of a broader and variable phenotypic spectrum known as oculoauriculovertebral dysplasia and always involves mandibular and ear malformations, but its severity varies.7,8 The mandibular deficiency usually is associated with microtia, macrostomia, and craniomaxillofacial asymmetry on the affected side. The maxilla, temporal bone, and orbit are also affected as a result of the primary malformation and not secondarily affected by the mandibular hypoplasia, as suggested by some.6 In addition to the skeletal components, neural, muscular, and soft tissues are also affected. The mandibular deformity in HFM was classified by Pruzansky2 in 1969. In his classification, a grade I mandibular deformity consists of a normally shaped but small mandible. Grade II is a small and abnormally shaped mandibular ramus. In grade III, the mandibular deformity is characterized by absence of the mandibular ramus including the temporomandibular joint. The treatment of HFM is centered on the mandibular deformity, but surgical timing is still controversial. The
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reason for this controversy relates to what clinicians believe is the facial growth potential in patients with HFM. Those who support early reconstruction, before skeletal maturity, assume that the mandibular skeletal asymmetry will worsen with time, and that early reconstruction will prevent secondary growth deformities.5,9-11 However, studies have found that the growth of the mandible on the affected side parallels that of the unaffected side, with the degree of asymmetry remaining relatively constant throughout craniofacial development.12-14 Another concern is the psychological adjustment problems caused by differences in facial appearance.15,16 Some clinicians consider that the surgery should be done earlier to prevent social adjustment problems. Others, who prefer to wait for the completion of growth, believe that expectations of reconstructive surgery can cause disillusionment when performed too early, because the patient will still grow asymmetrically and additional surgery will be required. The critical step in achieving better facial skeletal harmony is to restore maxillary and mandibular symmetry. Facial asymmetry is a main indication for orthognathic surgery. Traditionally, skeletal hypoplastic malformations are corrected with segment repositioning with autogenous bone grafts to increase the volume and size.17 Recently, in patients with HFM, distraction osteogenesis has been used for correcting mandibular asymmetry.8,18 Mandibular elongation by gradual distraction is mainly indicated in HFM patients with mandibular deformities grades I and II.19 Since HFM primarily affects not only the mandible but also the maxilla and the orbit, clinicians have suggested simultaneous maxillary and mandibular interventions to correct these asymmetries with a single procedure.19-21 The purpose of this study was to assess skeletal and soft tissue changes after simultaneous maxillary and mandibular distractions in patients with HFM. MATERIAL AND METHODS
Eight patients with HFM grade II mandibular deformity and maxillary asymmetry with a mean age of 13 years 2 months underwent combined maxillary and mandibular distractions.3 The surgical procedures were done under general anesthesia with nasotracheal intubation. A complete horizontal LeFort I osteotomy was performed. In contrast to the original method of Ortiz Monasterio et al,19 the pterygomaxillary junction was freed with a curved chisel on both sides, not only on the affected side. The unaffected maxillary side LeFort I osteotomy was loosely secured with 1 surgical wire placed above
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the maxillary first and second permanent molars. This wire acted as a hinge and pivot point where the maxillomandibular complex was expected to rotate toward the unaffected side (Fig 1). The ascending ramus was exposed along its anterior border behind the last molar and extended to the gonial angle and the surrounding area. The orientation of the osteotomy and the position of the distractor device determined the vector of distraction. A semiburied distraction device (Z€ urich II Distraction System; KLS Martin, Jacksonville, Fla) was positioned over the ramus in the planned direction (usually parallel to the long axis of the ramus) and fixed with self-tapping screws to secure the foot plates above and below the initially incomplete horizontal ramus osteotomy. The activating arm, from the semiburied device, was placed externally through a small incision below the mandibular angle. The osteotomy was completed and verified by opening the distractor. Before closure, the device was deactivated. The incision was closed, and rigid intermaxillary fixation with surgical wires was applied. Younger patients in the mixed dentition had custom-banded (maxillary and mandibular first permanent molars) arch bars with soldered hooks secured with circumdental wires for additional support during intermaxillary wire fixation and elastic therapy. In the adolescent patients, the orthodontic appliances were used for presurgical alignment and intermaxillary wire fixation and postoperative elastic therapy. The extent of the required bone elongation and the vector of the distraction were determined by the severity of the ipsilateral mandibular deformity, the shape of the contralateral or unaffected mandibular ramus, and the transverse cant of the occlusal plane. After 7 days (latency period), the device was lengthened by 0.5 mm twice a day, for an average of 22 consecutive days. In younger patients, vertical elongation of over 15 mm was usually not required; therefore, a single 15-mm distractor was able to correct the occlusal plane discrepancy. In the adolescent patients who required more than 15 mm of vertical distraction, we preplanned 2 consecutive surgical procedures; after full activation of the first 15-mm distractor, it was removed, and another distractor of 30 mm was placed to complete the required vertical distraction. This is a required step, since the bone available to fixate the device above and below the planned osteotomy over the ramus is only sufficient to accommodate a distractor of limited length (usually 15 mm). After the initial distraction, a longer distractor can be placed. This device is partially opened before placement to clear the newly generated bone. Another reason why in certain patients it is necessary to use 2 consecutive devices relates to the fact that the initial
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Fig 1. Schematic representation of bimaxillary unilateral vertical distraction surgical plan. A, Complete maxillary LeFort I (dashed line), unilateral horizontal ramus osteotomy; mandibular buried single-vector distractor; intermaxillary wire fixation (dotted line); single wire acting as a hinge (circle, contralateral side); vertical and curved arrows indicate the expected direction of the maxillary and mandibular movements after distraction. B, Expected vertical bone formation between osteotomies, downward and medial rotation of the maxilla and mandible to the contralateral side with leveling of the occlusal plane and restoration of symmetry. (Reproduced with permission from Figueroa and Polley.21)
placement is such that true vertical elongation is not obtained. The placement of the device has mainly a vertical component with a forward and medial vector because of the shape of the hypoplastic ramus and the contralateral ramus that needs to be emulated to correct as much as possible not only the size but also the form of the ramus. The placement of the distractor in this manner results in an effective loss of vertical length. Semiburied distractors are rigid and true to their length, but as explained above, the skeletal change is less than the true expression of the distractor; therefore, the activation to skeletal change ratio is not 1:1. The goal of bimaxillary distraction is mainly to obtain a level occlusal plane and not perfect symmetry of the gonial angles. The reason is that the vertical discrepancy is usually greater at the gonial angles, and if they are leveled, the occlusal plane will be canted downward on the affected side. The gonial angle asymmetry can be addressed secondarily with bone grafting combined with other required procedures—eg, genioplasty or soft tissue augmentation—to further improve appearance. Activation of the mandibular distractor resulted in vertical elongation of the affected ramus and medial displacement of both the maxillary and mandibular dentitions toward the unaffected side. This was possible because the patients had a complete affected side horizontal ramus osteotomy and a complete LeFort I
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osteotomy. In addition, they were placed in intermaxillary wire fixation to move the maxilla, the mandible, and the dentition as a unit. The patient's preoperative occlusion was preserved through intermaxillary wire fixation during distraction. After distraction, a consolidation period with wire intermaxillary fixation was completed (4 weeks for the younger patients and up to 6 weeks for the adolescent patients). After this period, the wires were replaced with 6-oz, ¼-in orthodontic elastics for the next 3 months. The patients were placed on a liquid diet during the intermaxillary fixation period and a soft diet for 4 to 6 weeks after the wires were removed. Orthodontic treatment was continued in the adolescent patients for 6 to 8 weeks after the wire fixation was removed. In the younger patients, the fixation appliances were removed after 2 to 3 months of elastic therapy. The distraction device was left in place for 6 months and removed in the operating room under general anesthesia. All patients had anteroposterior (AP) cephalometric radiographs and clinical frontal photographs taken before and after distraction in a standard manner. Skeletal and soft tissue facial asymmetries were respectively measured with AP cephalometric and soft tissue photographic frontal analysis. Radiographs and photographs were hand traced by the same investigator (E.F.S.). Each measurement was repeated 3 times, and the mean was recorded for data comparison. There was no statistical difference
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Table I. Description of the cephalometric AP analysis for the vertical and horizontal measurements Measurement Definition Vertical angle measurements HL-Co0 Co Angle between the HL and the bicondylar plane HL-NF0 NF
Angle between the HL and the nasal floor plane
HL-J0 J
Angle between the HL and the maxillary jugal points
HL-OCP
Angle between the HL and the occlusal plane
HL-Go0 Go
Angle between the HL and the gonial plane
Landmark Condylion (Co), external lateral marginal portion of the condylar head Nasal floor (NF), most inferior point on inside surface of the bony nasal cavity Jugal process (J), bilateral points on the jugal process of the maxilla at a crossing with the tuberosity of the maxilla Occlusal plane (OCP), horizontal plane passing through the molar and the incisors Gonion (Go), most lateral and inferior point of the mandibular angle
Horizontal angle measurements VL-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
Incision superior frontale (isf), midpoint between the maxillary central incisor at the level of the incisal edges Menton (Me), point on the inferior border of the symphysis directly inferior to the mental protuberance Anterior nasal spine (ANS), tip of the ANS below the nasal cavity and above the hard palate Top of the nasal septum (Tns), the highest point on the superior aspect of the nasal septum
Fig 2. Cephalometric analysis of vertical and horizontal changes. A, Horizontal planes relative to the HL and VL references used for analysis: 1, HL-Co0 Co bicondylar plane; 2, HL HL-NF0 NF nasal floor plane; 3, J0 J maxillary jugal plane; 4, HL-occlusal plane; 5, HL-Go0 Go gonial plane. B, Vertical planes used for analysis: 1, VL-isf superior midline; 2, VL-Me mental line; 3, Tns-ANS nasal septum deviation to the VL.
between the 3 measurements as determined by the Dahlberg22 double determination method. The measurements from the AP cephalograms are given in Table I. Two reference lines were traced (Fig 2) and used to make vertical and horizontal measurements: a horizontal line (HL), the line connecting the right and left latero-orbitale points, and a vertical line (VL), the line perpendicular to the HL through the center of crista galli (most constricted point of the projection of the perpendicular lamina of the ethmoid).
The gonial height ratio (HL-Go0 /HL-Go) and the ramus height ratio (CoGo0 /CoGo) were calculated from the AP cephalograms to compare the affected vs the unaffected sides. HL-Go0 /HL-Go is the ratio between the linear perpendicular distance from the horizontal reference line to the affected Go0 point, and the linear perpendicular distance from the horizontal reference line to the unaffected Go point. Co0 Go0 /CoGo is the ratio between the linear perpendicular distance from the affected Co0 point to the affected Go0 point, and the linear
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Fig 3. Cephalometric analysis of the ratio of affected vs unaffected gonial height (HL-Go0 /HL-Go) and ramus height (Co0 -Go0 /Co-Go).
perpendicular distance from the unaffected Co point to the unaffected Go point (Fig 3). In the photographic facial analysis, we used 3 bilateral soft tissue landmarks identified on the frontal photographs: bilateral endocanthion (inner commissure of the eye fissure) and the center point of a line connecting the right and left endocanthions. Two reference lines were traced on the frontal photographs (Fig 4): an HL, the line connecting the right endocanthion to the left endocanthion points; and a VL, the line perpendicular to the HL through the midline of the distance between the right and left endocanthion points. The measurements obtained from the frontal photographs are shown in Table II. Statistical analysis
Paired t tests were used to examine the difference between the preoperative (T1) and postoperative (T2, 6 months after surgery) measurements using the Statistical Package for Social Sciences software (version15.0; SPSS, Chicago, Ill). The power of the paired t test was calculated for each variable considering a sample size of 8 and an a of 0.05, using the free software power and sample size calculator (version 3.1.2; Statistical Solutions, Boston, Mass). RESULTS
The results of the AP cephalometric analysis demonstrated vertical improvement in all patients as seen by statistically significant decreases relative to the HL of the nasal floor angle (P 5 0.004), the maxillary jugal plane
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Fig 4. Planes used in the photographic analysis to evaluate vertical and horizontal facial changes relative to the HL and VL reference lines: 1, HL-sbal0 sbal nasal base plane; 2, HL-ch0 ch labial commissure plane; 3, VL-Pog vertical line chin point.
angle (P 5 0.008), the occlusal plane angle (P 5 0.003), and the gonial plane angle (P 5 0.035). Of the horizontal changes, only the menton to the VL measurement (P 5 0.004) was statistically significant (Table III). The ratio of the affected-unaffected gonial height (HL-Go0 /HL-Go) significantly improved by 20% from 65.85% to 86.61% (P 5 0.027). Ramus height (Co0 Go0 /CoGo) also significantly improved by almost 15% from 78.12% to 93.06% (P 5 0.042) (Table III). The findings demonstrated parallelism among the horizontal planes, vertical elongation of the affected side ramus height, and improvement of the midline deviation measurements. These were favorable changes toward restoring symmetry. The facial photographic analysis (Table IV) demonstrated significant changes, with the nasal plane improving by 3.00 (P 5 0.014), and the chin position changing toward the unaffected side by 4.83 (P 5 0.000), thus improving the midline symmetry, but without reaching full correction. Although not statistically significant, the labial commissure plane improved by 2.3 . The power of the t test (ie, the probability of correctly rejecting the null hypothesis) is included in Tables III and IV. Most variables with statistically significant differences between T1 and T2 (6 of 9) had an over 90% power for the t tests.
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Table II. Description of photographic facial analysis for the vertical and horizontal measurements Measurement Vertical angle measurements HL-sbal0 sbal (nasal base angle plane) HL-ch0 ch (labial commissure angle plane) Horizontal angle measurement VL-Pog (chin point)
Definition
Landmark
Angle between the HL and the nasal base plane Angle between the HL and the labial commissure plane, and 1 horizontal angle measurement
Subalare (sbal), lower limit of each alar base Cheilion (ch) point at each labial commissure
Angle between the VL and the chin point
Pogonion (Pog), most anterior midpoint of the chin
Table III. Vertical and horizontal angular measurements and ratios from anteroposterior cephalometric radiographs
Measurement Bicondylar plane (HL-Co0 -Co) ( ) Nasal floor plane (HL-NF0 NF) ( ) Maxillary jugal plane (HL-J0 J) ( ) Occlusal plane (HL-OCP) ( ) Gonial plane (HL-Go0 Go) ( ) Superior midline (VL-isf) ( ) Mental line (VL-Me) ( ) Nasal septum deviation (Tns-ANS) ( ) Gonial height (HL-Go0 /HL-Go) (%) Ramus height (Co0 -Go0 /Co-Go) (%)
T1 mean 6 SD 3.42 6 2.07 14.28 6 6.36 11.85 6 6.76 12.71 6 5.85 12.42 6 7.18 5.71 6 4.95 7.00 6 7.58 14.71 6 6.36 78.12 6 14.45 65.85 6 16.01
T2 mean 6 SD 2.14 6 1.46 8.00 6 6.55 3.00 6 4.12 4.42 6 4.07 4.00 6 5.13 3.85 6 5.08 3.4 6 7.05 11.14 6 6.36 93.06 6 9.32 86.61 6 12.35
Difference T1 T2 mean 6 SD 1.28 6 1.70 6.28 6 3.72 8.85 6 6.03 8.28 6 4.46 8.42 6 8.24 1.85 6 3.18 3.6 6 2.50 3.57 6 4.03 14.93 6 13.59 20.76 6 21.37
95% CI of the difference P value 0.093 0.004y 0.008y 0.003y 0.035* 0.174 0.033* 0.058 0.027* 0.042*
Lower 0.29 2.83 2.28 4.15 0.80 1.08 0.48 0.16 2.36 0.99
Upper 2.86 9.73 3.27 12.41 16.05 4.80 6.71 7.30 27.50 40.53
Power of paired t test (%) 41.2 97.7 94.2 98.8 69.3 25.0 93.5 55.5 76.0 64.4
0 Affected side. *P \ 0.05; yP \ 0.01.
Table IV. Vertical and horizontal angular measurements from frontal photographs Difference T1T2 Measurement T1 mean 6 SD T2 mean 6 SD mean 6 SD P value Nasal base angle plane (HL-sbal0 sbal) ( ) 7.50 6 5.91 4.25 6 5.25 3.00 6 2.00 0.014* Labial commissure angle plane (HL-ch0 ch) ( ) 9.75 6 4.99 6.75 6 6.89 2.33 6 3.14 0.128 8.75 6 6.23 3.75 6 6.23 4.83 6 0.98 0.000y Vertical line-chin point angle (VL-pog) ( )
95% CI of the difference Lower 0.90 0.96 3.80
Upper 5.09 5.62 5.86
Power of paired t test (%) 94.9 40.0 100.0
0
Affected side. *P \ 0.05; yP \ 0.01.
DISCUSSION
Reconstruction of an asymmetric mandible associated with a soft tissue deficiency is one of the most challenging problems in patients with HFM. Numerous surgical procedures have been advocated to correct facial asymmetry in these patients, including costochondral grafts, mandibular osteotomies combined with bone grafts, and maxillary osteotomies, done at an early age or in late adolescence.6,9,18 The results can be unpredictable because of undesirable resorption of the graft, leading to decreases in volume and strength of the reconstructed area. Furthermore, these procedures can cause significant morbidity at the donor site. Conventional orthognathic surgery, such as maxillary impaction on the unaffected side, is usually performed
with mandibular osteotomies.17 A large movement has a high risk for relapse because of the soft tissue deficiency of HFM. Recently, a complete fossa, condyle, and ramus reconstruction with a prosthetic replacement has been reported in adolescent patients with HFM with severe mandibular deformities.23 Distraction osteogenesis has provided an alternative in the treatment of craniomaxillofacial deformities.18 Its success is related to the fact that it uses the body0 s own healing mechanisms to produce new bone and elongate the soft tissues. This diminishes the need for autografts, thus decreasing morbidity. Mandibular elongation by gradual distraction can be done at any age.19 However, acute changes in mandibular shape result in postoperative alterations in dental occlusion, such
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Fig 5. A and D, Presurgical photographs of a 6-year-old boy with left HFM; B and E, after distraction; and C and F, follow-up treatment frontal facial and occlusion photographs at age 16 years. Note the transitional dentition stage (D and E) and no orthodontic appliances during distraction. A year after distraction the asymmetry was improved and the inferior midline was overcorrected, but at the 10year follow-up the cant of the occlusal plane and the chin point had moved back toward to the affected side.
as open bite on the affected side, crossbite on the contralateral side, and on occasion anterior crossbite.24,25 These consequences of mandibular unilateral distraction require orthodontic treatment over a long period of time. Postoperative orthodontic management can be difficult in young patients because of challenging mechanics and limited cooperation levels. In this study, combined maxillary and mandibular distractions were performed to correct the bimaxillary deformity in patients with HFM as initially suggested by Molina et al.19 A complete LeFort I was done simultaneously with a complete horizontal ramus osteotomy on the affected side, placement of a semiburied distraction device with a vertical vector, and wire intermaxillary fixation.19,21 External distractors were not used for our patients, since there are some inherent problems with them. These include facial scars and the tendency for the external fixation pins to loosen. Loose pins prevent the required long-term retention needed to ensure consolidation of the new regenerate and stability of the newly elongated ramus. Early removal of the external distractor permits muscle and soft tissue forces to act on the newly created bone and may lead to relapse. This problem is reduced by the ability to keep internal distractors in place for a prolonged period. This approach
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protects the newly created bone and allows the soft tissues to adjust to the new length. Although consolidation of the regenerate is usually advanced after 6 to 8 weeks, it continues with additional remodeling.26 In this sample, the devices were left longer (6 months) to accommodate the patients0 school schedules. The simultaneous distractions of the maxilla and the mandible are designed to correct the vertical and horizontal occlusal and chin asymmetries. However, these fail to correct, if present, an orbitozygomatic deformity.14,27 In our patients, all horizontal planes improved, but of the midline structures only the mental deviation from the vertical was statistically significant. This is explained by the fact that the structures closer to the osteotomy—nasal septum and maxillary incisors—did not change as much because they were closer to the center of rotation of the maxillomandibular complex. The maxilla pivoted around the surgical wire hinge, located on the unaffected side of the LeFort I osteotomy, thus limiting the lateral displacement of the hinge wire side of the maxilla toward the unaffected side. However, vertical lengthening of the maxilla and the mandible on the affected side resulted in a significant rotation of the chin toward the facial midline or the unaffected side.
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Fig 6. A, Predistraction; B, postdistraction; and C, 10-year follow-up AP cephalometric radiographs of the patient shown in Figure 5. Note the initial cant of the nasal, occlusal, and gonial planes and the deviation of the chin point to the ipsilateral side (A). After distraction (B), the cant of the 3 planes was improved, and the chin point was centered. However, at 10-year follow-up (C), the 3 planes had worsened and the chin point had deviated to the affected side.
Fig 7. A, Presurgical frontal facial photographs of a 14-year-old boy with left HFM; B, during distraction; and C, posttreatment frontal facial photographs at age 18 years 6 months. Note the improvement of facial symmetry.
Combined unilateral vertical maxillary and mandibular distractions corrected the cant of the occlusal plane and the chin deviation. The desired complete correction of the facial asymmetry, especially in the gonial region, was not fully accomplished, even though the changes were statistically significant (P 5 0.035). This was not surprising, since it is geometrically impossible to produce mandibular symmetry with a unilateral mandibular
distraction in a bone with a multidimensional deformity. It is likely that these patients will require additional surgical interventions to further improve their residual asymmetry.28 Facial asymmetry in patients with HFM results from shortness of the skeleton and hypoplastic soft tissues. The frontal photographic analyses showed that the nasal plane reached a better position related to the horizontal
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Fig 8. Occlusion photographs of the patient shown in Figure 7: A-C, presurgical; D-F, during distraction; and G-I, after treatment. Note the orthodontic appliances during distraction after initial alignment, intermaxillary fixation using the orthodontic appliances, and excellent facial symmetry and occlusion after distraction and orthodontic treatment.
line (P 5 0.014), the labial commissure leveled, the chin position moved to the unaffected side (P 5 0.000), and the mandibular border contour improved but did not achieve full correction. The lack of soft tissues and severely hypoplastic muscles of mastication make correction of HFM facial asymmetry a difficult challenge.29 The distraction process did not augment the lateral bulk of the gonial angle and the overlying muscles of mastication. Although the central aspect of the face was closer to the midline, the appearance of the face was flattened on the affected side, thus compromising overall facial symmetry. To minimize the residual facial asymmetry, a series of secondary surgical interventions is usually necessary. Microvascular or free dermis-fat grafts can produce excellent results to restore the deficient soft tissue facial volume.30,31 There is much debate on the timing of surgery in patients with HFM, for either growing or nongrowing patients. The introduction of distraction has added to the confusion. The debate results from different understandings of how a child with HFM grows. The authors
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of 1 study recommended early intervention to prevent the progression of the mandibular and maxillary deformities in growing children.9 It is based on the premise that if the deformity is left untreated, it will worsen over time. The second approach delays intervention until the completion of growth. It is based on the premise that the deformity, if left untreated, remains relatively stable over time.12,13,32 The severity of HFM varies widely, and the functional impairments (airway, mastication, and speech) should dictate the timing of the surgical intervention. Patients with respiratory distress, and feeding and speech issues are candidates for early interventions. However, the parents need to be fully aware that additional corrective skeletal and soft tissue procedures will become necessary during late adolescence to fully address the facial asymmetry and functional impairments. To date, there is no evidence supporting the effectiveness of early mandibular osteodistraction in patients with HFM.14 In our study, 4 patients had surgery in the early mixed dentition to minimize the deformity. Surgery
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Fig 9. A, Predistraction; B, postdistraction; and C, 4.5-year follow-up AP cephalometric radiographs of the patient shown in Figure 7. Note the initial cant of the nasal, occlusal, and gonial planes and the deviation of the chin point to the ipsilateral side (A). After distraction (B), the cant of the 3 planes was improved, and the chin point was centered. Note the increase in ramus height, stability of all planes, and chin position after distraction and at 4.5-year follow-up (C).
Fig 10. Occlusal photographs of a 16-year-old boy with HFM: A and C, before orthodontic alignment; B and D, after orthodontic alignment. Note the asymmetry of the mandibular arch before orthodontic treatment with the decreased distance of the affected side to the midline (arrows). The arch was well aligned after treatment (D), with improved symmetry. Congruent and symmetrical arches allow for better outcomes with bimaxillary unilateral vertical distraction.
was performed with full awareness by the parents that as the child reaches skeletal maturity, more surgical procedures would be required.14,33 Although we observed
partial improvements in facial asymmetry, control of the occlusion was challenging because the children were in the transitional dentition stage, and also
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because of their lack of compliance with the elastics and the limitations of the appliances designed for transitional dentitions (Figs 5 and 6). On the other hand, the most successful cases treated in this small series were the adolescent patients with full permanent dentition, with fixed orthodontic appliances placed to align and level the arches before the bimaxillary distraction. No older patient had a secondary ipsilateral open bite or a contralateral crossbite. Postoperative occlusal relationships were close to ideal after the bimaxillary distraction procedure, and the patients required only routine orthodontics to complete treatment during a 6- to 12-month postoperative period; they have remained stable after the surgical and orthodontic treatments (Figs 7-9). The younger patients in our sample will require additional interventions such as additional distraction, double-jaw orthognathic surgery, genioplasty, and soft tissue augmentation. Case selection for a determined surgical procedure is critical. From our experience, we suggest that patients with clinically significant occlusal plane discrepancies, with congruent maxillary and mandibular arch forms when adequate occlusal interdigitation can be achieved, with minor AP maxillomandibular discrepancies, and without excessive maxillary gingival exposure on the unaffected side are appropriate for bimaxillary distraction. However, patients with excessive maxillary gingival show on the affected side can be managed as described here, but later, the vertical maxillary excess can be corrected by maxillary impaction. Maxillary impaction is the most stable procedure in orthognathic surgery.34 Patients with mandibular dentoalveolar arch asymmetry with a skewed arch should be first aligned with orthodontic treatment before proceeding with bimaxillary distraction (Fig 10). In patients in the permanent dentition with well-aligned arches, fixed orthodontic appliances are used for intermaxillary fixation, comfort (avoiding arch bars), postoperative elastic therapy, and finishing orthodontic occlusal details. As with many clinical distraction studies, our small sample size makes it difficult to draw definitive conclusions. Series from other authors had similar35 or even smaller sample sizes8,11,17,31,36-38 to study the effects of distraction in HFM. The relatively rare incidence of HFM and the number of patients who fit the criteria for bimaxillary distraction result in limited experience in the various treatment centers. The challenge for obtaining enough randomized subjects motivated the development of the National Dental Practice-Based Research Network.39 The aim of this initiative is to build an investigative union of practicing dentists and academic scientists collaborating to refine dental care.
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Therefore, intercenter collaborative studies are necessary to eventually develop a consensus for an effective protocol to treat patients with HFM. In this study, skeletal and soft tissue changes after bimaxillary distraction osteogenesis were measured with AP cephalometric radiographs and frontal facial photographs. Technological advances in 3-dimensional photogrammetry and radiologic scanning techniques will allow improved evaluation of outcomes.8,40 The use of 3dimensional virtual surgical planning and CAD/CAM generated splints and surgical guides will assist in selecting the best surgical interventions for a particular condition and can assist surgeons with accurate surgical execution, thus improving outcomes.41-45 CONCLUSIONS
Simultaneous maxillary and mandibular distraction improved facial balance and symmetry in all patients with HFM. Patients in the permanent dentition with fixed appliance orthodontic treatment and wellaligned dental arches responded better to this approach than did younger patients. The severity of the skeletal and soft tissue deficiencies may dictate the need for additional surgery such as orthognathic surgery, genioplasty, and soft tissue enhancement procedures to obtain improved facial balance and symmetry. ACKNOWLEDGMENT
We thank Daniel Ranjbar, Lawrence, Kansas, for his expert orthodontic support in the treatment of the patient shown in Figures 4, 7, and 8. REFERENCES 1. Grabb WC. The first and second branchial arch syndrome. Plast Reconstr Surg 1965;36:485-508. 2. Pruzansky S. Not all dwarfed mandibles are alike. Birth Defects Orig Artic Ser 1969;5:120-9. 3. Figueroa AA, Pruzansky S. The external ear, mandible and other components of hemifacial microsomia. J Maxillofac Surg 1982; 10:200-11. 4. Murray JE, Kaban LB, Mulliken JB. Analysis and treatment of hemifacial microsomia. Plast Reconstr Surg 1984;74:186-99. 5. Kaban LB, Mulliken JB, Murray JE. Three-dimensional approach to analysis and treatment of hemifacial microsomia. Cleft Palate J 1981;18:90-9. 6. Molina F, Ortiz Monasterio F. Mandibular elongation and remodeling by distraction: a farewell to major osteotomies. Plast Reconstr Surg 1995;96:825-40. 7. Gorlin RJ, Cohen MM Jr, Hennekam RCM. Syndromes of the head and neck. 4th ed. New York: Oxford University Press; 2001. 8. Chow A, Lee HF, Trahar M, Kawamoto H, Vastardis H, Ting K. Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a long-term study. Am J Orthod Dentofacial Orthop 2008;134: 724-31.
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Sant'Anna et al
9. Kaban LB, Moses MH, Mulliken JB. Surgical correction of hemifacial microsomia in the growing child. Plast Reconstr Surg 1988;82:9-19. 10. Grayson BH, Santiago PE. Treatment planning and vector analysis of mandibular distraction osteogenesis. Atlas Oral Maxillofac Surg Clin North Am 1999;7:1-13. 11. Jansma J, Bierman MW, Becking AG. Intraoral distraction osteogenesis to lengthen the ascending ramus. Experience with seven patients. Br J Oral Maxillofac Surg 2004;42:526-31. 12. Rune B, Selvik G, Sarnas KV, Jacobsson S. Growth in hemifacial microsomia studied with the aid of roentgen stereophotogrammetry and metallic implants. Cleft Palate J 1981;18:128-46. 13. Polley JW, Figueroa AA, Liou EJ, Cohen M. Longitudinal analysis of mandibular asymmetry in hemifacial microsomia. Plast Reconstr Surg 1997;99:328-39. 14. Nagy K, Kuijpers-Jagtman AM, Mommaerts MY. No evidence for long-term effectiveness of early osteodistraction in hemifacial microsomia. Plast Reconstr Surg 2009;124:2061-71. 15. Khetani MA, Collett BR, Speltz ML, Werler MM. Healthrelated quality of life in children with hemifacial microsomia: parent and child perspectives. J Dev Behav Pediatr 2013;34: 661-8. 16. Bemmels H, Biesecker B, Schmidt JL, Krokosky A, Guidotti R, Sutton EJ. Psychological and social factors in undergoing reconstructive surgery among individuals with craniofacial conditions: an exploratory study. Cleft Palate Craniofac J 2013;50:158-67. 17. Yamauchi K, Takahashi T. Maxillary distraction osteogenesis combined with mandibular osteotomy to correct asymmetry of the maxillomandibular complex. Plast Reconstr Surg 2006;118: 39e-45e. 18. McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1-8. 19. Ortiz Monasterio F, Molina F, Andrade L, Rodriguez C, Sainz Arregui J. Simultaneous mandibular and maxillary distraction in hemifacial microsomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 1997;100:852-61. 20. Molina F, Ortiz Monasterio F, de la Paz Aguilar M, Barrera J. Maxillary distraction: aesthetic and functional benefits in cleft lip-palate and prognathic patients during mixed dentition. Plast Reconstr Surg 1998;101:951-63. 21. Figueroa AA, Polley JW. Mandibular distraction osteogenesis. Operative Techniques. Otolaryngol Head Neck Surg 2002;13: 17-28. 22. Dahlberg G. Statistical methods for medical and biological students. New York: Interscience Publications; 1940. 23. Movahed R, Teschke M, Wolford LM. Protocol for concomitant temporomandibular joint custom-fitted total joint reconstruction and orthognathic surgery utilizing computer-assisted surgical simulation. J Oral Maxillofac Surg 2013;71:2123-9. 24. Hanson PR, Melugin MB. Orthodontic management of the patient undergoing mandibular distraction osteogenesis. Semin Orthod 1999;5:25-34. 25. Matsumoto K, Nakanishi H, Koizumi Y, Yamano M, Hashimoto I, Satake S, et al. Occlusal difficulties after simultaneous mandibular and maxillary distraction in an adult case of hemifacial microsomia. J Craniofac Surg 2004;15:464-8. 26. Samchukov M, Cope J, Cherkashin A. Biological basis of new bone formation under the influence of tension stress. In: Craniofacial distraction osteogenesis. St Louis: Mosby; 2001. p. 21-36. 27. Polley JW, Figueroa AA. Distraction osteogenesis: its application in severe mandibular deformities in hemifacial microsomia. J Craniofac Surg 1997;8:422-30.
577
28. Molina F. Mandibular distraction: surgical refinements and longterm results. Clin Plast Surg 2004;31:443-62,vi-vii. 29. Huisinga-Fischer CE, Vaandrager JM, Prahl-Andersen B. Longitudinal results of mandibular distraction osteogenesis in hemifacial microsomia. J Craniofac Surg 2003;14:924-33. 30. Inigo F, Rojo P, Ysunza A. Aesthetic treatment of Romberg's disease: experience with 35 cases. Br J Plast Surg 1993;46:194-200. 31. Inigo F, Jimenez-Murat Y, Arroyo O, Fernandez M, Ysunza A. Restoration of facial contour in Romberg's disease and hemifacial microsomia: experience with 118 cases. Microsurgery 2000;20:167-72. 32. Kusnoto B, Figueroa AA, Polley JW. A longitudinal threedimensional evaluation of the growth pattern in hemifacial microsomia treated by mandibular distraction osteogenesis: a preliminary report. J Craniofac Surg 1999;10:480-6. 33. Meazzini MC, Mazzoleni F, Bozzetti A, Brusati R. Comparison of mandibular vertical growth in hemifacial microsomia patients treated with early distraction or not treated: follow up till the completion of growth. J Craniomaxillofac Surg 2012;40:105-11. 34. Proffit WR, Phillips C, Turvey TA. Stability following superior repositioning of the maxilla by LeFort I osteotomy. Am J Orthod Dentofacial Orthop 1987;92:151-61. 35. Cho BC, Shin DP, Park JW, Baik BS. Bimaxillary osteodistraction for the treatment of facial asymmetry in adults. Br J Plast Surg 2001;54:491-8. 36. Tehranchi A, Behnia H. Treatment of mandibular asymmetry by distraction osteogenesis and orthodontics: a report of four cases. Angle Orthod 2000;70:165-74. 37. Marquez IM, Fish LC, Stella JP. Two-year follow-up of distraction osteogenesis: its effect on mandibular ramus height in hemifacial microsomia. Am J Orthod Dentofacial Orthop 2000;117: 130-9. 38. Wolford LM, Bourland TC, Rodrigues D, Perez DE, Limoeiro E. Successful reconstruction of nongrowing hemifacial microsomia patients with unilateral temporomandibular joint total joint prosthesis and orthognathic surgery. J Oral Maxillofac Surg 2012;70:2835-53. 39. Kokich VG. Consider joining the orthodontic practice-based research network. Am J Orthod Dentofacial Orthop 2013; 144:323. 40. Trahar M, Sheffield R, Kawamoto H, Lee HF, Ting K. Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a preliminary report. Am J Orthod Dentofacial Orthop 2003;124:639-50. 41. Gateno J, Xia J, Teichgraeber JF, Rosen A. A new technique for the creation of a computerized composite skull model. J Oral Maxillofac Surg 2003;61:222-7. 42. Xia JJ, Gateno J, Teichgraeber JF, Christensen AM, Lasky RE, Lemoine JJ, et al. Accuracy of the computer-aided surgical simulation (CASS) system in the treatment of patients with complex craniomaxillofacial deformity: a pilot study. J Oral Maxillofac Surg 2007;65:248-54. 43. Xia JJ, Shevchenko L, Gateno J, Teichgraeber JF, Taylor TD, Lasky RE, et al. Outcome study of computer-aided surgical simulation in the treatment of patients with craniomaxillofacial deformities. J Oral Maxillofac Surg 2011;69:2014-24. 44. Polley JW, Figueroa AA. Orthognathic positioning system: intraoperative system to transfer virtual surgical plan to operating field during orthognathic surgery. J Oral Maxillofac Surg 2013;71:911-20. 45. Shibazaki-Yorozuya R, Yamada A, Nagata S, Ueda K, Miller AJ, Maki K. Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with conebeam computed tomography. Am J Orthod Dentofacial Orthop 2014;145:579-94.
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