Management of Facial Asymmetry

Oral Maxillofacial Surg Clin N Am 19 (2007) 395–422 Management of Facial Asymmetry George K.B. Sándor, MD, DDS, PhD, Dr Habil, FRCDC, FRCSC, FACSa,b,c,d,e,f,g,*, Taylor P. McGuire, BSc, DDS, MSc, FRCDCh, Leena P. Ylikontiola, DDS, PhDf,g, Willy S. Serlo, MD, PhDi,j, Pertti M. Pirttiniemi, DDS, PhDf,k a Graduate Program in Oral and Maxillofacial Surgery and Anesthesia, University of Toronto, Toronto, Ontario, Canada b Pediatric Oral and Maxillofacial Surgery at the Hospital for Sick Children and Bloorview Kids Rehab Centre, Toronto, Ontario, Canada c Mount Sinai Hospital, Toronto, Ontario, Canada d Regea Institute of Regenerative Medicine, University of Tampere, Tampere, Finland e Oral and Maxillofacial Surgery, Institute of Dentistry, University of Oulu, Oulu, Finland f Institute of Dentistry, University of Oulu, Oulu, Finland g Cleft Lip and Palate Surgery, University of Oulu, Oulu, Finland h Facial Cosmetic and Reconstructive Surgery, Department of Surgery, Baptist Memorial-Golden Triangle, Columbus, MS, USA i Pediatric Surgery, Oulu University Hospital, Oulu, Finland j Department of Pediatric Surgery, Oulu University Hospital, Oulu, Finland k Oulu University Hospital, Oulu, Finland No human face is perfectly symmetric in its structure [1]. In fact, most hard and soft tissue facial asymmetries present in the general population exist as subconscious, innate inequities that contribute to the uniqueness of every individual. Alongside averageness, sexual dimorphism, and youthfulness, symmetry has emerged as one of the four major determinants of attractiveness [2–4]. The causes of asymmetries affecting the face are numerous (Box 1). Likewise, there are even more underlying etiologic sources responsible for each one of them. They are most easily classified by simplistically separating them into one of three categories: congenital, developmental, or acquired. Congenital defects can be further subclassified into malformations, deformations, and disruptions. Malformations are those types of congenital defects that arise because of an aberrant developmental process that takes place early during embryogenesis [5], whereas disruptions are morphologic defects that arise later in the fetal period secondary to failure of an otherwise normal developmental process [6]. Malformations, deformations, and disruptions can be interrelated. They are not mutually exclusive and they may produce asymmetries [7]. This article describes the management of some of the causes of asymmetries of the face. Frontal plagiocephaly * Corresponding author. The Hospital for Sick Children, S-525, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. E-mail address: george.sandor@utoronto.ca (G.K.B. Sándor). The term plagiocephaly, from the Greek plagios (oblique) and kephale (head), means distortion of the head, and refers clinically to craniofacial asymmetry [8]. It is a descriptive term that is used by clinicians to describe a specific 1042-3699/07/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.coms.2007.05.001 oralmaxsurgery.theclinics.com 396 SÁNDOR Box 1. Some causes of facial asymmetry Deformational plagiocephaly Synostotic plagiocephaly Clefting conditions Hemifacial hyperplasia Hemifacial atrophy Hemifacial microsomia Costochondral graft overgrowth Condylar and hemimandibular hyperplasia Idiopathic condylar hypoplasia Traumatic condylar hypoplasia Torticollis Hamartomas Vascular malformations Neoplasms morphology of upper facial asymmetry found in affected patients [9]. All patients who present for consultation with an abnormally shaped head require careful evaluation because the treatment of plagiocephaly varies significantly according to the underlying cause. There are two main causes of plagiocephaly: deformational plagiocephaly (DP) and craniosynostotic plagiocephaly (CP). Infantile plagiocephaly is most commonly caused by positional deformation of the skull. Although there has been a major decrease in the incidence of sudden infant death syndrome since the American Academy of Pediatrics released its recommendation in 1992 that infants be placed down for sleep in a non-prone position [10], the incidence of DP has increased dramatically with a concurrent increase in the incidence of torticollis [9,11,12]. In particular, infants who require newborn intensive care, particularly premature infants, are more prone to DP and ipsilateral dolichocephaly. Fortunately, the former can be prevented or minimized by proper positioning [12]. Similarly, DP can often be treated successfully with cranial molding-helmet therapy alone [13]. Craniosynostotic plagiocephaly is less common. It should always be considered in the differential diagnosis, as its functional implications and treatment considerations are different. Craniosynostosis, a premature fusion of cranial sutures, can arise as an isolated, sporadic, nonsyndromic congenital defect or as part of a larger craniofacial syndrome. Each of these, in turn, may be divided by origin into primary or secondary. The current primary craniosynostosis et al hypothesis suggests that the overproduction of bone at the suture is the cause of the craniosynostosis, with closure of the affected suture directly affecting subsequent brain and cranial growth secondarily through altered intracranial pressure (primary suture fusion model) [14]. The secondary craniosynostosis hypothesis attributes decreased cranial base growth or abnormal brain growth as the underlying cause of the craniosynostosis (cranial base, secondary brain parenchyma models, respectively) [14]. In the more common primary cases, premature fusion inhibits normal skull growth in a direction perpendicular to the orientation of the fused suture as described by Virchow’s Law [15]. This process, in turn, leads to skeletal compensation and abnormal craniofacial growth at adjacent sutures. The importance of symmetric cranial vault expansion cannot be overstated, as elevated intracranial pressure (ICP) is the most significant functional problem associated with untreated craniosynostosis [15,16]. One third of patients who have craniofacial dysostosis syndromes and about 15% to 20% of children who have single-suture craniosynostosis have a documented increase in ICP [17,18]. Multiple-suture craniosynostosis has a worse neurologic prognosis than single-suture craniosynostosis [18]. Isolated craniosynostosis still has been shown to be associated with a threeto fivefold increase in risk for cognitive deficits or learning/language disabilities [19]. The causal basis for this association is unclear. No particular calvarial suture (sagittal, metopic, left or right unilateral coronal) has yet been associated with a higher risk for problems [19]. Furthermore, persistent postoperative raised ICP has been described in 6% to 15% of patients who have craniofacial dysostosis [17]. There are multifactorial causes of increased ICP in both types of patients, which include altered cerebral perfusion pressures (CPP), upper airway obstruction, and hydrocephalus [15,17]. Hydrocephalus is rarely observed in nonsyndromic craniosynostosis, and in these cases is usually attributable to coincidental disorders. Conversely, it is a common feature of syndromic craniosynostosis, affecting at least 40% of patients who have Crouzon, Pfeiffer, or Apert syndrome [20]. At the present time, the underlying mechanisms and overall proportionate effect of each on raised ICP remains uncertain. Decreased CPP as a consequence of elevated ICP is believed by some to be the one most responsible for the neurologic, cognitive, and ophthalmologic sequelae exhibited frequently by these children, however [21]. MANAGEMENT OF FACIAL ASYMMETRY The prevalence of all forms of craniosynostosis has been estimated to be 1 in 1000 live births [22], with most cases arising as sporadic occurrences of unknown cause [15,23]. Syndromic craniosynostosis is usually genetic, presenting with autosomal dominant or recessive patterns, depending on the specific syndrome [15]. Craniofacial dysostosis is another term that should not be used incorrectly in place of craniosynostosis, because the former encompasses abnormalities of not only the cranial sutures but also abnormal development of the cranial base and facial bones because of other affected sutures [15,16]. Current treatment algorithms for syndromic/nonsyndromic craniosynostosis and craniofacial dysostoses all make use of surgery, but the specific indications, timing, and exact techniques used for the reconstruction of each can vary widely from patient to patient and center to center [9,15,16,24,25]. Classification The classification of craniosynostosis is based on cranial vault morphology. As such, skull shape is representative of the underlying fused sutures only and not of the cause. Synostotic frontal plagiocephaly arises because of the premature closure of one of the coronal sutures (Fig. 1A). The fusion of an ipsilateral frontal bone to its adjacent parietal bone results in the formation of one single large segment of calvaria with restricted growth potential. Osseous compensation for rapid infantile brain growth in the face of this problem then takes place at all remaining patent sutures, but is most prevalent along both sides of the contralateral coronal suture [15]. 397 deviation of the nose to the flattened side (Fig. 1B) [9,15]. Contralateral displacement of the chin and anterior fontanelle are also commonly exhibited, which further enhance the degree of facial asymmetry. Various adjunctive methods used to aid clinicians further in diagnosis and treatment planning include digital and standard anthropometry [26–28], serial standardized digital photographs [27,29], direct head circumference measurements [29], and thermoplastic [30] and manual plastercasting techniques [31]. Many centers are also developing and using newer three-dimensional (3D) clinical imaging technologies in an attempt to further enhance this process [31]. The regular use of conventional skull radiographs has decreased substantially as highresolution CT scans, including 3D osseous surface reformations with stereolithic skulls, have become a standard element in the evaluation of craniofacial anomalies in many centers (Fig. 1C). CT studies have shown that the endocranial base dysmorphology of patients who have plagiocephaly is cause-specific for synostotic frontal and posterior synostosis as compared with DP [32]. Consequently, 3D-CT endocranial base images are often used to assist in the differential diagnosis of plagiocephaly [33]. When initial clinical and radiographic examinations performed are suggestive of nonsyndromic synostotic frontal plagiocephaly, prospective patients are then jointly reviewed by a team consisting of a pediatric surgeon, pediatric neurosurgeon, pediatric ophthalmologist, radiologist, and craniomaxillofacial surgeon. Treatment Patient evaluation Craniosynostotic plagiocephaly, which warrants surgical correction, is documented clinically and radiographically and must be accurately differentiated from DP. Although differentiation by physical examination between synostotic frontal plagiocephaly and DP is possible for an experienced observer, inexperienced clinicians may have difficulty making an anatomically accurate diagnosis [26]. Classic isolated synostotic frontal plagiocephaly results in a predictable craniofacial morphology in affected patients. A focused clinical examination usually reveals the ipsilateral supraorbital rim and orbit to be superiorly and posteriorly displaced, with concomitant widening of the palpebral fissure, flattening of the forehead, and The timing of surgery in infants is most often dictated by the absence or presence of documented increases in ICP. Without evidence of increased ICP, our group’s preference is to delay definitive reconstruction until the child is between 12 and 24 months of age. Earlier intervention, between the ages of 2 and 9 months, is commonly performed in infants who have increased ICP attributable to the tripling of intracranial volume that occurs with normal unobstructed brain growth over this time frame [15,34,35]. The overall goal in the treatment of nonsyndromic synostotic frontal plagiocephaly is to restore facial symmetry and balance to the craniofacial complex by focusing on the distortions of the forehead and orbits. Achieving this therefore requires the surgical manipulation and 398 SÁNDOR et al Fig. 1. (A) Preoperative 3D CT scan showing fusion of the right coronal suture in this child who has craniosynostotic plagiocephaly. (B) Frontal photograph of an 18-month-old girl who has right-sided craniosynostotic plagiocephaly. Note the displacement of the chin toward the left. (C) Stereolithic skulls of patients who have plagiocephaly. These models are useful for surgical planning of complex craniomaxillofacial conditions. (D) Elevation of frontal bone flap. (E) Fronto-orbital bandeau is removed, trimmed, and scored to permit bending. The resorbable fixation is applied to the inner surface of the bandeau to increase its stability and keep most of the fixation material hidden. (F) The radiating triangles are cut from the frontal bone flap and adapted to eliminate the preoperative asymmetry. The resorbable fixation material can be softened in a warming bath to permit more accurate adjustments in contour. (G) The triangles adapted and fixated to the fronto-orbital bandeau. (H) Specially designed bone collector or suction trap to harvest bone slurry during cranioplasty procedures (CSMT, Mississauga, Canada). (I) The remaining osseous gaps are grafted over with bony fragments or slurry collected using a suction trap. The sheet-like resorbable fixation material acts like a membrane to help promote bony regeneration. (J) Final readaptation of pericranium after use of fibrin glue to keep bone slurry in calvarial defects. (K) Closure of the scalp with zigzag incision to allow cranial reshaping without soft tissue tension. (L) Immediate postoperative frontal view of corrected cranial asymmetry. MANAGEMENT OF FACIAL ASYMMETRY 399 Fig. 1 (continued) repositioning of multiple osseous regions, including the affected orbit, bilateral supraorbital ridge, forehead, and temporoparietal regions. Although the technical aspects of every reconstruction vary from individual to individual, most craniofacial surgeons reshape and reposition the calvaria and orbit using one of three procedures first introduced by Tessier in 1967: 1. Unilateral fronto-orbital (‘‘canthal advancement’’) advancement 2. Bilateral fronto-orbital advancement/modeling without nasal osteotomies and straightening 3. Bilateral fronto-orbital advancement/modeling with closing wedge nasal osteotomy [36,37]. Of the three different surgical techniques, the results achieved by the bilateral approach are most often considered better than those attained with the unilateral techniques [38,39]. In addition, 400 SÁNDOR osteotomies of the nasal bones are recommended in the cases of older children who have severe nasal deviation associated with dislocation of the nasoethmoidal complex [39]. Many modifications of these basic osteotomy approaches have been implemented since they were first described. More recently, distraction osteogenesis has also been used for the correction of plagiocephaly [40] and other types of craniosynostosis [41], on its own and in conjunction with conventional osteotomies [42]. When surgically correcting nonsyndromic synostotic frontal plagiocephaly, our preference is the ‘‘Daisy Petal’’ [43] or ‘‘Sunrise’’ [44] or what our team refers to as the triangle modification of the bilateral fronto-orbital advancement. Using a zig-zagged coronal incision, access to the frontoparietal and orbital regions is obtained. This incision allows the possibility of multiple ‘‘V’’ to ‘‘Y’’ advancements to accommodate the alterations of head contour produced by the osteotomy. The zig-zagged coronal incision also results in a more esthetic result than a straight incision. A craniotomy is performed to allow for the removal of the bilateral frontoparietal regions of the calvaria (Fig. 1D). A standard bilateral fronto-orbital bandeau is then removed, adjusted, and advanced for later fixation to the stable posterior calvaria using resorbable osteosynthesis plates (Fig. 1E). Next, the flattened frontal bone is cut with oblique radial osteotomies starting at the bregma into numerous triangles (Fig. 1F). The triangles are rotated axially in a medial direction (Fig. 1G). Internal table corticotomies are performed to recurve the flattening and to obtain a proper curve in the coronal plane. The remaining osseous gaps are then grafted using remaining calvarial bone slurry harvested with a specially designed suction trap, shown in Fig. 1H (CSMT, Mississauga, Canada) [45]. All bone fragments are fixated to each other using resorbable osteosynthesis plates (Fig. 1I). At the completion of this procedure, fibrin glue is placed over the grafted sites and the pericranium is treated carefully to obtain a better adaptation of the new bone shape (Fig. 1J). On final layered closure of the incision, this technique creates a stable unit that provides immediate improvements in craniofacial symmetry to the frontoparietal regions (Fig. 1K, L). Torticollis Torticollis is a condition of unknown cause, consisting of a unilateral tilt of the neck to one et al side caused by the development of a fibrous band in the sternocleidomastoid (SCM) muscle [7]. This condition is usually unilateral and results in the development of a cervicofacial asymmetry with the interpupillary plane slanted downward and the chin deviated to the side of the affected SCM muscle (Fig. 2A, B). The condition has been treated in the past with a stepped myotomy and lengthening of the SCM muscle but this has a tendency to recur. Our group supports the excision of the entire SCM muscle and its band from its origin to its insertion. Failure to correct torticollis may result in the development of a future more significant facial asymmetry. Torticollis may also be associated with other intracranial findings, such as intracerebral cysts and hydrocephalus (Fig. 2C) [35]. We recommend that in cases with torticollis that have not been present in the neonatal period MRI evaluation should be done to exclude such lesions. Unilateral clefting conditions Unilateral clefting syndromes, by their very nature, can cause profound facial asymmetries. The exact nature of the deformity depends on the location and extent of the cleft. With respect to the production of facial asymmetries it is the location of the cleft relative to the midline that is of importance. Nonsyndromic unilateral cleft lip with or without cleft palate is the most common cause of congenital asymmetry of the craniomaxillofacial skeleton. It occurs with an incidence of 0.77 per 1000 births, more commonly on the left side and in males [46]. The unilateral cleft lip deformity has effects on the facial skeleton and nasal structure that go far beyond the lips. Even in the repaired state unilateral cleft patients may exhibit striking asymmetries of their noses (Fig. 3) and may require secondary cleft lip rhinoplasties [47]. Hemifacial hyperplasia Hemifacial hyperplasia is a rare sporadic developmental condition that can lead to pronounced facial asymmetry that grows with the patient throughout childhood (Fig. 4A). Both soft tissue and hard tissue structures can be affected, including the cartilage, facial bones, and teeth (Fig. 4B). Hemifacial hyperplasia is a segmental form of congenital hemihyperplasia that may be complex, involving half the body. Although the MANAGEMENT OF FACIAL ASYMMETRY 401 Fig. 2. (A) Left-sided torticollis with fibrous band in left sternocleidomastoid muscle, occlusal plane canted down to the left, and chin point deviation to the left. (B) Posteroanterior (PA) cephalogram in a patient who has left-sided torticollis showing severe head tilt to the left and a downward cant of the occlusal plane to the left. (C) Intracerebral cyst found in patient who had torticollis. condition is generally unilateral, a limited bilateral crossover can occur in hemihyperplasia [48]. There is an association of Wilms tumors of the kidney in patients who have hemifacial hyperplasia, along with other possible findings such as nevi, pigmentation, and telangiectasia of the skin; unilateral enlargement of the cerebral hemisphere; seizures; mental retardation; and conductive hearing loss [48]. A tumor surveillance protocol with abdominal ultrasound examinations is recommended for children who have congenital hemihyperplasia to rule out rare Wilms tumors [49]. The correction of the facial deformities may require the harmonious serial reduction of both hard and soft tissue elements after growth cessation. Hemifacial atrophy Hemifacial atrophy is a rare condition of unknown cause also known as Parry-Romberg syndrome. It is a progressive condition that results in severe atrophy of all of the hard and soft tissues of one side of the face to varying degrees (Fig. 5A, B). Some believe that it is the result of the interruption of the trophic effects of the superior cervical ganglion, because the condition has been produced by cervical sympathectomy in the rat model [50]. It is associated with Jacksonian epilepsy with partial unilateral focal seizures, alopecia on the affected side, and cutaneous pigmentation changes. It has been associated with systemic lupus erythematosus, coup de sabre scleroderma, Rasmussen encephalitis, and Lyme disease. Once the progressive nature of the condition has stabilized, management has included both hard tissue and soft tissue augmentations to mask the effects of the localized atrophy. Such procedures have included silicone and fat injections, hydroxyapatite and coral granule augmentations [51], alloplastic implants, and free 402 SÁNDOR Fig. 3. A 36-year-old patient who has cleft lip and palate with profound residual nasal asymmetry that distorts the symmetry of the rest of the face. tissue transfers of fat using omentum or latissimus dorsi, for example. The results have been variable. Hemifacial microsomia Hemifacial microsomia (HFM) is an umbrella term that encompasses a group of variably expressive asymmetric craniofacial malformations. These malformations are ultimately derived from aberrations of development of derivatives of the et al first and second branchial arches [5,52]. HFM on its own commonly presents with an extremely variably asymmetric unilateral or bilateral hypoplasia of the orbits, maxilla, mandible, ear, cranial nerves, and related soft tissues (Fig. 6A, B). Malformations during early embryonic life involving other structures derived from the first and second branchial arch do, however, potentially result in a wider spectrum of anomalies that encompass diverse and heterogeneous phenotypes within the oculoauriculovertebral spectrum (OAVS) [53]. Other clinically descriptive terms used to describe HFM may include otomandibular dysostosis, lateral facial dysplasia, first and second branchial arch syndrome, unilateral intrauterine facial necrosis, unilateral craniofacial microsomia, and oculoauriculovertebral dysplasia [54]. HFM is second only to nonsyndromic cleft lip and palate as the most common congenital anomaly affecting the craniofacial region [5]. It is found to occur with an estimated incidence of 1 in 3500 to 5600 live births with a slight 3:2 male predominance [5]. Most patients are of normal intelligence. Although bilateral cases do occur, 70% to 85% of the cases are unilateral, most commonly involving the right side. Clefting may also occur in patients who have HFM, with up to 23% [55] of patients demonstrating a macrostomia compared with a lower 10% to 15% incidence of cleft lip and palate [54,55]. Many patients also have external ear deformities ranging from ear tags to microtia and anotia. Fig. 4. (A) A 24-year-old who has hemifacial hypertrophy of left side of face. Note the maxillary dental midline has shifted to the right. (B) Stereolithic skull showing the underlying bony deformity in hemifacial hyperplasia that contains hyperplastic soft and hard tissues. MANAGEMENT OF FACIAL ASYMMETRY 403 Fig. 5. (A) Frontal photograph of an 18-year-old woman who has hemifacial atrophy of the right upper third of the face involving the frontal, right periorbital, and right zygomatic areas. (B) Coup de sabre–like deformity near glabellar region outlined with marking pen. Note preexisting craniotomy scar for neurosurgical treatment of focal epileptiform seizures. In its worst presentation patients who have hemifacial atrophy may exhibit Rasmussen encephalopathy with atrophy of one hemisphere. The true pathophysiologic basis underlying this condition is not yet fully known, but two important concepts are recognized. First, based on experimental evidence and clinical observations, HFM is still believed to be one of several structural anomalies that are postulated to result from vascular disruption [56], with rupture of the stapedial artery still playing a central role [57]. A second cause may be abnormal migration of neural crest cells, because HFM may occur in conjunction with cardiac anomalies or other craniofacial morphologic malformations belonging to the OAVS spectrum [55,58]. Classification The wide variation of hard and soft tissue defects reported with HFM has led to the development of diverse classification systems. A comparative chronologic synopsis of these systems can be found in Table 1 [59–61]. Most clinicians agree that a useful HFM classification system must be centered on a functional temporomandibular joint (TMJ) and the mandible because these components are of prime importance among all other defects when it comes to reestablishing form and function. As such, the KabanHFM system seems well suited to be applied to treatment planning and surgical management. From a reconstructive perspective, types I and IIA are similar because both have a functional TMJ. Types IIB and III are more akin to each other because the TMJ apparatus, mandible, and related musculature are either severely malformed, totally absent, or inadequately positioned and often require alternative reconstructive techniques in an attempt to reconstitute normal form and function (Tables 2 and 3). Patient evaluation The successful management of HFM-induced facial asymmetry requires the attainment of accurate clinical, photographic, and radiographic records. Qualitative and quantitative hard and soft tissue measurements of the facial skeleton, overlying soft tissue, and dentoalveolar structures must be obtained by analyzing the patient in all three planes of space. The auditory and facial nerve function must also be evaluated. Standardized facial photographs, including a right and left three-quarter oblique and a submentovertex view, are taken. Additionally, frontal views of the patient at rest, in full smile, and while biting on a wooden tongue blade or a Fox plane are obtained to assess occlusal canting relative to the interpupillary plane (Fig. 7A). Intraoral records should include study models mounted on a semiadjustable articulator and intraoral photographs of the occlusion and maxillary and mandibular arches. Plain film radiographs (frontal and lateral cephalogram, panoramic, and 404 SÁNDOR et al Fig. 6. (A) Preoperative photograph of an 18-year-old man who has right-sided hemifacial microsomia classified as type IIA. (B) Lateral profile photograph showing partially reconstructed right ear affected with microtia. (C) Preoperative panoramic radiograph of patient in Fig. 5A, B. (D) Preoperative PA cephalogram of patient in Fig. 5A, B. (E) Preoperative lateral cephalogram of patient in Fig. 5A, B. (F) Le Fort I osteotomy to correct occlusal cant by impacting the maxilla on the left side and extruding the maxilla on the right side. (G) The gaps left by extruding the maxilla are grafted using bone harvested from the iliac crest. Rigid fixation has been applied to the osteotomy site and bone grafts. (H) An inverted ‘‘L’’ osteotomy was chosen to help reposition the mandible on the right making the vertical length of the ramus longer and placing the inferior segment laterally with an iliac crest one graft over top to minimize the concave defect in the right angle region of the mandible. (I) Postoperative panoramic radiograph showing the healed fragments and their hardware. A differential impaction and extrusion using a Le Fort I osteotomy of the maxilla was used. The right mandible was treated with an inverted ‘‘L’’ osteotomy and bone graft on the lateral aspect of the ramus of the mandible with left-sided sagittal split osteotomy. A genioplasty was performed to place the asymmetric chin into the midline. (J) Postoperative PA cephalogram showing the laterally and inferiorly repositioned angle of the mandible. (K) Postoperative lateral cephalogram showing the new anteroposterior position of the jaws. (L) Postoperative frontal photograph. Note the newly filled-out right-angle region of the mandible. (M) Postoperative profile view photograph showing the jaw line. a submentovertex) are often still obtained, but 3D-CT reconstructions and stereolithic skulls (Fig. 8A, B) illustrating the finer elements of the patient’s hard and soft tissue defects are quickly becoming the standard of care [62–64]. General treatment principles The overall strategy for patients who have HFM varies considerably. All comprehensive phased treatment plans are individually developed based on each patient’s age, physical examination, and assessment of photographs, radiographs, mounted models, and classification. There are, however, some important concepts to appreciate: The extent and rate of progression of facial asymmetry that develops in HFM depends directly on the pre-existing skeletal morphology [65]. MANAGEMENT OF FACIAL ASYMMETRY 405 Fig. 6 (continued) Untreated HFM affects the development of the maxilla because normal vertical growth of the ipsilateral maxilla is restricted by the poorly developed vertical growth of the corresponding mandible. Regardless of the skeletal type present, the end-stage deformity can be reduced by early childhood intervention because HFM is a progressive condition affected by growth [66]. 406 SÁNDOR et al Fig. 6 (continued) Treatments vary along a wide spectrum from the use of functional dentoalveolar orthopedic appliances to total TMJ reconstruction. Additional surgical procedures to correct secondary osseous and soft tissue deformities are commonly required. Management of hemifacial microsomia type I Treatment begins preferably in the primary or early mixed dentition stage with the introduction of a functional dentoalveolar orthopedic appliance. The goals at this early stage are to maximize appositional mandibular bone growth on the affected side in an anterior and inferior direction by exerting tension on the attached muscles and soft tissues [67,68]. In postpubescent HFM-type I adolescents and adults who do not have prior orthodontic or surgical interventions, conventional double-jaw orthognathic surgery and bone grafting may be required to correct the deformity. Le Fort I osteotomy is required to address the canted occlusal plane, while at the same time allowing for optimal maxillomandibular horizontal or vertical positioning and final incisor tooth show. Concomitant mandibular osteotomies may consist of either bilateral sagittal split ramus osteotomies or bilateral vertical ramus osteotomies or an Table 1 Overview of available hemifacial microsomia classification systems Author Date introduced HFM classification system Kaban et al [59] 1981 David et al [60] 1987 Vento et al [61] 1991 Types I, II (A & B), and III: Designed to relay the underlying types of skeletal deformity based on the mandible and the TMJ as a center of reference SAT system: Acronym used to highlight the three major anatomic components that are altered in HFM ‘‘S’’ for skeletal malformations, ‘‘A’’ for auricular involvement, ‘‘T’’ for tissue defects Modeled after the TMN classification of tumors OMENS system: Expanded on ‘‘SAT’’ with acronym describing the five major manifestations ‘‘O’’ for orbital distortion, ‘‘M’’ for mandibular hypoplasia, ‘‘E’’ for ear deformity, ‘‘N’’ for nerve defects, ‘‘S’’ for soft tissue deficiencies Each category is totally independent and the degree of deformity, including normal, is rated for each group Abbreviations: TMJ, temporomandibular joint; TMN, Tumor, Node, Metastasis. III IIB IIA Type I HFM commonly displays hypoplastic morphology with little to no malformation Hypoplastic Small but Present Preserved to Present but underdeveloped; may contain fatty infiltration present varying degrees Type IIA HFM commonly displays hypoplastic morphology with increasing malformation; TMJ is usually positioned symmetrically for opening Hypoplastic to Hypoplastic, Present Present; more malformed As with Type I with increasing severity of hypoplasia absent and cone than Type I shaped No articulation between the condyle and glenoid fossa seen; TMJ is displaced inferiorly, medially, and anteriorly Absent Rudimentary Present Absent Hypoplastic Hypoplastic to absent; not attached Rudimentary to condyle Absent Absent Absent Absent Rudimentary Absent Rudimentary to absent I Lateral pterygoid Temporalis Condyle Glenoid fossa Mandibular morphology Coronoid process Kaban type Table 2 Osseous and muscular morphology of hemifacial microsomia Gonial angle Masticatory muscle morphology Masseter and medial pterygoid MANAGEMENT OF FACIAL ASYMMETRY 407 ipsilateral vertical ramus osteotomy with a contralateral sagittal split osteotomy (Fig. 6C–H). Regardless of the osteotomy design, mandibular movements usually make up the asymmetric correction, including advancement on the affected side and setback on the unaffected side. Anteroposterior position and final vertical adjustments are subject to the Le Fort I performed for the occlusal plane leveling and incisor show. The selection of a vertical ramus versus a sagittal split osteotomy design primarily depends on the degree of asymmetry correction required to align the maxillary and mandibular midlines with facial midline. Finally, a genioplasty may also be performed to level and reposition the chin back to the facial midline vertically (Fig. 6I–M). Management of hemifacial microsomia type IIA Similar to HFM-type I, treatment of patients who have type IIA commences in early childhood with the use of a functional dentoalveolar orthopedic appliance. In such cases surgical vertical mandibular lengthening is usually required to adequately correct the asymmetry because the mandibular hypoplasia is more severe. Fortunately, early intervention occasionally precludes the need for a compensatory Le Fort I osteotomy. Adults who have HFM-type IIA, however, almost always require a bimaxillary or double-jaw orthognathic approach identical to that used for patients who have HFM-type I for 3D surgical correction of their underlying facial asymmetry. Management of hemifacial microsomia type IIB Childhood treatment of patients who have HFM-type IIB begins once again with functional dentoalveolar orthopedic appliances. Attempts to maximize affected maxillary and mandibular growth and to decrease dentoalveolar compensations are received with the understanding that they are less effective at alleviating the overall asymmetry because of the severity of the underlying defects. Consequently, an initial surgical procedure may be performed during the mixed dentition stage when midface asymmetry begins to occur. The absence of a functional TMJ with no articulation and no translation (see Tables 2 and 3) requires that the rudimentary, malpositioned one be removed. A new TMJ is then simultaneously fabricated in a newer, more ideal location to allow for symmetric joint function. Autogenous reconstruction consisting of costochondral and iliac crest grafts are preferred to alloplasts and are used to construct a new glenoid fossa and 408 SÁNDOR et al Table 3 Functional and adjunctive characteristics of hemifacial microsomia Movement Miscellaneous TMJ Kaban type Hinge rotation I, IIA Normal with unrestricted movement IIB, III Absent but movement unrestricted Condylar translation Reduced (type I), absent (type IIA) Absent Mandibular deviation on opening Facial nerve function Hearing Soft palatal movement Toward ipsilateral side Varies Decreased on ipsilateral side Decreased on ipsilateral side Toward ipsilateral side Varies Decreased on ipsilateral side Decreased on ipsilateral side ramus/condyle unit (Fig. 7B–J). As with HFM type I/IIA, isolated mandibular osteotomies to gain vertical length and correct rotation purposely incorporate the placement of an ipsilateral posterior open bite. This occlusion is slowly reduced at regular intervals over a 1- to 2-year time frame to allow for occlusal leveling as unrestricted maxillary growth occurs. Older, nongrowing patients who have HFM-type IIB still require reconstruction of the nonfunctional TMJ. This reconstruction is again preferentially addressed with autogenous bone grafting. Simultaneous Le Fort I and contralateral mandibular osteotomies are mandatory, however, if the surgeon is to adequately address not just the occlusal plane but all other 3D asymmetric issues. Management of hemifacial microsomia type III Patients who have HFM-type III exhibit the greatest severity of osseous, muscular, and soft tissue hypoplasia or aplasia. The use of functional dentoalveolar orthopedic appliances in these patients is avoided because the severity of the defects usually prevents any meaningful correction with growth. Rather, early treatment of patients who have HFM-type III consists of TMJ reconstruction as with HFM-type IIB. The emphasis in patients who have type III is on early reconstruction in the primary dentition stage (ages 2–5) as soon as the midface deformity begins to develop. The surgical reconstruction of the TMJ, mandibular lengthening osteotomies, and management of the surgically created open bite are identical to those described for patients who have HFM-type IIB. Adult patients who have HFM-type III with no prior surgical intervention require extensive osseous and soft tissue reconstruction similar to the nongrowing patients who have HFM-type IIB. Management of hemifacial microsomia types I- III with distraction osteogenesis Distraction osteogenesis (DO) is now a wellknown method of forming bone in the craniofacial skeleton through osteotomy and sequential stretching of the healing callus. This technique has been used in syndromic and nonsyndromic patients in whom the magnitude of planned movements required for elimination of existing hard tissue discrepancies would be unattainable with conventional orthognathic osteotomies because of soft tissue limitations, instability, and relapse (Fig. 9A). Moreover, inductive plastic effects on the hard and soft tissues and the possibility of molding the results have led to DO gaining increasing popularity in the treatment of congenital and acquired deformities [69]. Although the use of DO for the reconstruction of severe mandibular deformities in patients who have HFM-type III has been described [70], it has been applied with increasing frequency to patients who have less severe forms of HFM (Fig. 9B, C) [71] and has even been used to simultaneously address maxillary and mandibular defects [72,73]. Early problems with a lack of rotational control encountered with unidirectional distractors are now being addressed with multiplanar mandibular (Fig. 10) and maxillary distractors [74]. DO still has the disadvantages of increased treatment time, increased hardware costs, the possibility of external fistulae, and an increased incidence of iatrogenic apertognathia requiring compensatory or staged Le Fort I osteotomy [75]. Although aesthetic and psychologic advantages of DO are well accepted, it should be applied in the treatment of MANAGEMENT OF FACIAL ASYMMETRY 409 Fig. 7. (A) Canted occlusal plane in this 6-year-old girl who has a right-sided type IIB hemifacial microsomia is accentuated by the use of a tongue blade placed between the teeth in occlusion when compared with the plane of the interpupillary line. (B) Asymmetry of the lower third of the face with canting of the occlusal plane upward to the right in a 6-year-old girl who has right-sided type IIB hemifacial microsomia. (C) Note the canted occlusal plane of the dentition and shift of the mandibular dental midline to the left. (D) Preoperative panoramic radiograph showing type IIB hemifacial microsomia deformity. (E) Costochondral graft harvested to reconstruct right temporomandibular articulation. (F) Costochondral graft secured with rigid fixation screws. Note the occlusal wafer is wired in to begin treatment of the canted occlusal plane with selected grinding of the functional appliances. (G) Costochondral graft evident on the postoperative panoramic radiograph. (H) Tracing of the canted occlusal plane preoperatively. (I) Tracing of the leveled occlusal plane following treatment with functional appliances. (J) Functional appliance with adjustable occlusal plane. HFM after careful patient selection with a realization of the short- and long-term limitations. Soft tissue correction in hemifacial microsomia types I–III Many other deformities associated with HFM must also be addressed in addition to the osseous defects. For instance, as many as three [65] to six [54] staged surgical reconstructions for the treatment of auricular deformities may be required. External ear anomalies range from skin tags to complete absence of the pinna. Secondary treatment of other osseous contour defects of the mandible, zygoma and temporal bone may be corrected with autogenous rib, calvarial, or iliac onlay grafts or with custom fabricated alloplasts. Rhinoplasty and revision genioplasty may also be entertained at this stage 410 SÁNDOR et al Fig. 7 (continued) [65]. Remaining soft tissue anomalies and volume defects should only be addressed after all hard tissue defects have been reconstructed and facial growth has terminated. Although the severity of a given soft tissue defect most often parallels that of the underlying skeletal deformity [62], imaging studies serve to remind clinicians that the extent of skeletal hypoplasia of involved facial bones does not necessarily always predict the full extent of volume loss or hypoplasia in the attached musculature [76]. Nevertheless, the treatment of soft tissue hypoplasia in HFM follows two major paths. Minor volume defects may be successfully addressed using injectable fillers, such as autologous fat grafts [77,78]. Larger, more severe defects are often best addressed using fasciocutaneous microvascular flaps because they are capable of providing a greater amount of augmentation [78,79]. Costochondral graft overgrowth Costochondral graft overgrowth is a rare complication of costochondral grafting for the reconstruction of the ramus/condylar unit. Such overgrowth threatens to undo the reconstruction or correction of a mandibular asymmetry. Perrot and colleagues [80] have followed 26 patients who had 33 costochondral grafts for an average of 48 months. There were no signs of linear overgrowth of the costochondral grafts in 7 growing patients who had 8 reconstructed joints. They reported 2 cases of what they termed lateral contour overgrowth with an abnormal increase of the mass of the graft in the region of the costochondral junction [80]. Four mandibular asymmetries developed in the 19 nongrowing patients who were treated with costochondral grafts. Two were the result of contralateral resorption of the unoperated condyles and two were the result of remodeling with decrease in the lengths of the reconstructed ramus condylar units [80]. We present a case of costochondral graft overgrowth that involves a patient who was treated for apparent trismus at the age of 8 years with a left-sided costochondral graft (Fig. 11A– C). She was lost to follow-up for 12 years and returned with massive costochondral graft overgrowth (Fig. 11D–J). Although such cases are rare, they do alert the clinician to the possibility of late costochondral graft overgrowth. Condylar and hemimandibular hyperplasia Significant facial asymmetry can occur with unchecked unilateral growth of the mandible. MANAGEMENT OF FACIAL ASYMMETRY 411 Fig. 8. (A) Severe medial ward displacement of residual ramus and angle of mandible seen on the frontal view of this 3D stereolithic skull. (B) Lateral view of stereolithic skull of severe type IIB hemifacial microsomia. Some clinicians believed this could be classified as a type III but there seemed to be some condylar vestige. Perhaps the two best-documented conditions exemplifying these types of mandibular asymmetry are those of condylar hyperplasia (CH) and hemimandibular hyperplasia (HH). CH, as the name implies, produces excessive unilateral growth of the condyle resulting in associated facial asymmetric deformities [81]. HH is similarly characterized by a diffuse enlargement of the condyle, the condylar neck, and the mandibular ramus and body [82]. Although both are recognized to be self-limiting, non-neoplastic pathologic processes, much debate concerning their cause, pathogenesis, and true relationship still exists. In considering their underlying causes, both conditions have been documented in patients following previous trauma [83–86]. Conversely, they have also been shown capable of idiopathic development [87,88]. They can arise in patients of varying age and growth states and hence can exist as either developmental or acquired processes. The exact cause and pathogenesis for each condition is thus unknown. Suggestions and theories put forth to explain their existence vary from neurotrophic, circulatory, and hormonal disturbances [84] to intrauterine influences [81]. Despite these unknowns, both disorders have been shown to have at their basis persistent or resumed activity of the cartilaginous growth center of the mandibular condyle [81,82,85,89,90]. Classification The morphologic configuration of the unilateral hyperplastic condyle and mandible lies at the heart of controversy when it comes to the classification of these two types of facial asymmetry. In 1985 Toller [91] classified CH into two types based on the manifestation of the facial asymmetry. According to Toller [91], type I CH is the more common of the two subtypes, with the classic presentation of excessive vertical growth of the condylar neck leading to a contralateral deviation of the chin and a concomitant posterior dental cross-bite. The less common type II deformity described by Toller [91] manifests a downward vertical enlargement and bowing of the mandibular ramus and body on the ipsilateral side with the presence of a more severe posterior occlusal open bite and crossbite. The condylar head is usually normally shaped in type I CH and may be normal or hyperplastic in type II. In 1986 Obwegeser and Makek [85] attempted to reclassify type I and type II CH into hemimandibular elongation (HE) and HH, respectively. They believed that the term ‘‘condylar hyperplasia’’ referred to hyperplasia of the condyle alone and that it should not be used to describe the two hemimandibular anomalies as suggested by Toller [91]. Rather, they indicated that these two types of mandibular hyperplasia existed in pure 412 SÁNDOR et al Fig. 9. (A) Stereolithic skulls are particularly helpful in planning distraction osteogenesis procedure not only to ensure the correct vectors of distraction but also to ensure that the required hardware will fit on the unpredictably hypoplastic ramus of the mandible. (B) External distractor that can be adjusted in three planes of space to permit more accurate guidance of the distracted mandible. (C) Successful distraction of the mandibular segments bilaterally shown on this postoperative panoramic radiograph. and mixed forms based on the clinical, radiographic, and histologic findings they had noted in several patients. In 1996 Chen and colleagues [92] proposed that all cases of HH and HE actually represented variations of condylar overgrowth. They believed that unchecked condylar overgrowth progresses into HH and HE. Despite these differences in nomenclature, clinicians should recognize that two forms of mandibular hyperplasia exist. They should also appreciate that the overall severity of the facial asymmetry and degree of underlying skeletal and dental compensation with each form is highly variable and ultimately depends on the age of the patient and the rate and length of time hyperplasia has been active [91,93]. Patient evaluation The clinical picture varies widely, depending on the onset of the growth disturbance relative to the age of the patient, the rate of growth, and the extent of mandibular involvement. The most typical clinical history and presentation is one in which the patient or the patient’s parents have been aware for some time of a progressive deviation of the lower jaw to the contralateral side (Fig. 12A). This deviation may or may not be associated with skeletal and dental prognathism and is rarely associated with pain or malfunction of either the affected or unaffected TMJ. Compensatory skeletal adjustments, including occlusal canting (Fig. 12B), may exist despite the absence of an ipsilateral posterior MANAGEMENT OF FACIAL ASYMMETRY Fig. 10. A multiplanar internal distractor to help guide the mandible downward and forward. 413 most often using technitium-99 (tech-99). They are thus commonly used to identify the presence of active growth in several tissues, including osteoblasts potentially located within the condylar and mandibular regions (Fig. 12F). More recent advances in nuclear imaging for use in CH and HH include the use of single photon emission computed tomography (SPECT). Compared with planar scintigraphy, SPECT increases image contrast and improves lesion detection and localization [96]. This technique has already been shown to demonstrate enhanced diagnostic accuracy for CH and HH compared with conventional planar tech-99 scanning [97–99]. There are, however, limitations in sensitivity and specificity with false positive results most often occurring in patients who have associated TMJ infection, dysfunction, or neoplasia [95,100–102]. Nevertheless, as access to this technique becomes available, its enhanced ability to visualize hard and soft tissue in 3D combined with its potential for assessing structures in real time [101] will undoubtedly lead to the replacement of standard tech-99 scans for use in craniofacial imaging. Treatment open bite (Fig. 12C). This manifestation is plausible, of course, in the actively growing patient in whom the hyperplastic growth rate on the affected side is slow enough that it still allows for compensatory ipsilateral maxillary vertical growth, thereby maintaining a functional, yet canted, occlusion. Conventional radiographic examination of CH or HH performed in a growing child may additionally demonstrate the typical enlargement of the affected condyle, elongation/enlargement of the ipsilateral ascending ramus and mandibular body, and tilted occlusal plane (Fig. 12D, E). Although previously serial clinical and plain film radiographic views alone were used for diagnosis and treatment planning, the condylar growth activity, which often dictates surgical treatment strategies, cannot be assessed by conventional radiologic procedures [94]. Serial radionuclide skeletal scintigraphy or isotope bone scanning has been successfully used for years in the assessment of CH and HH causing mandibular asymmetry [94,95]. Conventional bone scans are planar or two-dimensional nuclear medicine imaging techniques that make use of comparative ratios of radioisotope uptake by cells exhibiting increased metabolism and turnover, Treatment modalities and philosophies of care for patients afflicted with these conditions vary greatly. This difference is because of the variability in age, overall skeletal growth, presence or absence of active hyperplasia, and degree of facial asymmetry with which patients may present. These variables are further compounded in complexity by other issues affecting the final treatment path, including the aggressivity or extent, timing, and potential number of procedures that may be required to restore proper form and function. Many practitioners believe strongly that early diagnosis is paramount with the primary principle of treatment being the elimination of the pathologic condylar growth site as soon as possible to mitigate the extent of the developing facial asymmetry that so often follows [89,93,103,104]. Proponents of this treatment strategy have therefore successfully used a wide array of surgical techniques ranging from isolated high condylar shave to staged and simultaneous TMJ and orthognathic surgery [103,104]. CH and HH are self-limiting pathologic processes by virtue of their nonneoplastic natures [81,82]. Additionally, the function of the TMJ, regardless of the severity of the facial asymmetry, is usually normal. The attempted elimination of the hyperplastic tissue 414 SÁNDOR et al Fig. 11. (A) Preoperative lateral cephalogram of this 6-year-old child who has apparent trismus. (B) Left costochondral graft placed at the age of 6 years shown on the panoramic radiograph. (C) Postoperative lateral cephalogram showing fixated costochondral graft. (D) Frontal photograph of same patient as in Fig. 10A now 17 years old with severe overgrowth of left costochondral graft. (E) Left lateral oblique view photograph of patient who has left costochondral graft overgrowth. (F) Right lateral profile photograph of patient who has left costochondral graft overgrowth. (G) Submental view showing extreme deviation of chin point to the right. (H) Severely displaced dentition in anterior and right directions. (I) Panoramic radiograph demonstrating severe overgrowth of left-sided costochondral graft to ramus of mandible. (J) Chin point deviation to the right demonstrated on PA cephalogram in patient who has overgrown left costochondral graft. MANAGEMENT OF FACIAL ASYMMETRY 415 Fig. 11 (continued) does not necessarily mean that further surgery will be avoided at the completion of growth [105]. Consequently our centers, along with others, believe that strong consideration should be given to: (1) refraining from any surgery until growth activity has ceased [82], and (2) the avoidance of open joint surgery in most patients unless absolutely indicated [106]. Condylar hypoplasia CH may be developmental, seemingly without an apparent underlying cause, in which case it is called idiopathic CH. The most common cause of CH is acquired, secondary to trauma of the mandible. It is also possible that at least some cases of idiopathic CH are caused by occult trauma that neither the parents nor the practitioner may be aware of. Unilateral CH may also rarely occur as a result of avascular necrosis of the mandibular condyle or unilateral involvement of the temporomandibular joint by rheumatoid arthritis. Traumatic injuries of the mandibular condyle can cause a hemarthrosis, particularly with intracapsular fractures of the mandibular condyle. Such an injury may predispose the patient to frank bony ankylosis of the TMJ, particularly if the mandible is immobilized for a prolonged period of time. At the very least, trauma to the mandible can lead to scarring and restricted translation of the mandibular condyle. Proffit and colleagues [107] have termed this functional ankylosis or soft tissue extracapsular ankylosis. Waite and Urban [108] believe the greater the degree of translational restriction, the greater the facial deformity. Fig. 13A displays a coronal CT image of the right condyle of an 8-year-old girl who sustained comminution and concomitant intracranial displacement of her right condylar head into the middle cranial fossa following a fall from a bicycle. The results attained with closed reduction attained and gradual traction can be seen in Fig. 13B. The patient was also placed on a program consisting of early vigorous mobilization. 416 SÁNDOR et al MANAGEMENT OF FACIAL ASYMMETRY 417 Fig. 13. (A) Right mandibular condyle displaced into the middle cranial fossa of this 8-year-old girl who fractured her mandible and temporal bone falling from a bicycle. (B) Dislocated fracture of right mandibular condyle retrieved from right middle cranial fossa by slow sustained traction. (C) Disorganized healing of comminuted intracapsular fracture of right mandibular condyle treated with aggressive mobilization from 2 weeks after the injury. (D) Panoramic radiograph 2 years after injury showing healed condylar mass with shortening of the right ramus of the mandible. (E) Deviation of the mandibular dental midline toward the affected right side 2 years after the injury. (F) Frontal photograph showing deviation of chin point toward the hypoplastic right mandibular condyle 4 years following the injury. (G) Submental view showing deviation of the chin to the right side. (H) Progressive right-sided deviation of the mandibular dental midline in keeping with the now apparent deviation of the skeletal midlines 4 years following the injury. (I) Skeletal deviation with posttraumatic condylar hypoplasia despite aggressive mobilization and maintenance of a satisfactory range of motion. leading to a clinically obvious mandibular asymmetry (Fig. 13F, H, I). The authors believe that in addition to translational restriction, damage of this nature sustained by the mandibular condyle and the surrounding tissues leads to restricted growth, which in this particular case was beyond the compensatory capacity of the functional matrix. : At the end of treatment a deformed but functional right TMJ existed (Fig. 13C, D). Two years following the injury the patient developed a shift of her mandibular dental and skeletal midline to the right (Fig. 13E). Despite ongoing active TMJ mobilization therapy and simultaneous orthodontic intervention, her midlines progressively worsened over the ensuing 2 years, Fig. 12. (A) Frontal photograph of 11-year-old girl who has left-sided hemimandibular hyperplasia. Note the deviation of the chin to the right and the occlusal plane cant upward to the right. Note also the position of the left inferior border of the mandible compared with the right. (B) Further demonstration of the occlusal cant using a tongue blade. (C) Left profile photograph of patient who has left hemimandibular hyperplasia. (D) Left-sided hemimandibular hyperplasia shown in this PA cephalogram. (E) Note the left hemimandibular overgrowth in this 11-year-old girl who has enlargement of the condylar head and neck, ramus, angle, and body of the mandible on the left side. (F) Note the increased scintillographic activity on these scans in the left condylar area consistently through all views of the scans. 418 SÁNDOR et al Fig. 13 (continued) The management of facial asymmetry resulting from CH depends on the degree of hypoplasia. In the traumatic case described above, interceptive orthodontics should prevent canting of the maxillary occlusal plane, thereby potentially limiting the surgical treatment to the lower jaw only. In such instances a derotational osteotomy of the mandible after growth cessation could be accomplished either by using either bilateral sagittal split osteotomies or a right sagittal split osteotomy and left intraoral vertical ramus osteotomy. If the condyle becomes grossly hypoplastic and severe trismus develops, then a costochondral graft to reconstruct the ramus/condyle unit may be necessary. Summary Fig. 14. Skeletal relapse in a 28-year-old woman 2 years after bimaxillary correction of an asymmetric prognathism despite negative condylar technetium scans preoperatively. The preceding cases and corresponding descriptions are designed to highlight some of the more common causes of facial asymmetry. Successful surgical outcomes are predicated on a sound knowledge base that allows for accurate diagnostic evaluation, growth monitoring, and well-planned adaptable single or serial treatments aimed at the correction of such deformities. Long-term monitoring of patients who have facial MANAGEMENT OF FACIAL ASYMMETRY asymmetry is important to ensure that complications caused by delayed growth are also managed (Fig. 14). References [1] Peck S, Peck L. Skeletal asymmetry in esthetically pleasing faces. Angle Orthod 1991;61(1):43–8. [2] Rhodes G. The evolutionary psychology of facial beauty. Annu Rev Psychol 2006;57:199–226. [3] Bashour M. An objective system for measuring facial attractiveness. 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