Unilateral craniofacial microsomia. Part I. Mandibular analysis

A decade of clinical research on clinical characteristics, medical treatments, and surgical treatments for individuals with craniofacial microsomia: What have we learned?

AIM

This article provides a review of a decade of clinical research studies on clinical features, medical interventions, and surgical interventions for individuals with craniofacial microsomia (CFM). We also provide recommendations for future clinical research.

METHOD

A systematic search of literature was conducted in Embase and PubMed/MEDLINE Ovid. All publications from 2010 to 2020 that included at least 10 individuals with CFM were considered relevant for this study.

RESULTS

A total of 91 articles were included. In the past decade, many new studies on CFM have been published providing more insight on the diagnosis and management of patients with CFM. This review encompasses findings on the clinical difficulties patients with CFM encounter, including the craniofacial and extracraniofacial characteristics of patients with CFM and its related clinical consequences on breathing, feeding, speech, and hearing.

CONCLUSIONS

A considerable number of large multicenter studies have been published in recent years, providing new insights in the clinical consequences of CFM. The phenotypic variety between patients with CFM makes patient-specific treatment tailored to individual needs essential. The research and development of clinical care standards might be challenging because of the heterogeneity of CFM. Future research on clinical and patient-reported outcomes can help identify optimal treatment strategies. Cooperation between craniofacial centers, using uniform registration and outcome measurement tools, could enhance research and future care for these patients.

LEVEL OF EVIDENCE

Level IV.

Three-dimensional functional unit analysis of hemifacial microsomia mandible-a preliminary report

Background

The aim of this study was to present three-dimensional (3D) structural characteristics of the mandible in the hemifacial microsomia. The mandible has six distinct functional units, and its architecture is the sum of balanced growth of each functional unit and surrounding matrix.

Methods

In order to characterize the mandibular 3D architecture of hemifacial microsomia, we analyzed the mandibular functional units of four hemifacial microsomia patients using the 3D reconstructed computed tomography (CT) images. And we compared the functional unit size between affected and non-affected side.

Results

The length of condyle and angle showed significant differences between affected and non-affected sides. However, the length of mandibular body showed insignificant differences. The size differences between affected and non-affected side were observed at the condyle, angle, and body in descending order.

Conclusions

This preliminary study suggests that the main etiopathogenic units are condyle and angle in the hemifacial microsomia mandible. Further investigation with the increased number of subjects will be helpful to establish treatment modality by etiopathogenic targeting of hemifacial microsomia.

Investigation of maxillofacial morphology and dental development in hemifacial microsomia

Objective : Hemifacial microsomia (HFM) is a congenital anomaly characterized by unilateral underdevelopment of the mandible and ear. This study was conducted to characterize maxillofacial morphology and dental development in Japanese patients with HFM. Design : This is a retrospective hospital-based study. Patients : The subject population comprised 12 boys and 12 girls (average age, 9.3 years) diagnosed with HFM. Main Outcome Measures : We used posteroanterior (PA) and lateral cephalograms obtained at the first visit to analyze maxillofacial morphology and orthopantomograms to compare dental development between the affected and unaffected sides. Dental development was graded according to Nolla's stages of tooth calcification. Results : PA cephalogram analysis showed that the occlusal plane inclined upward on the affected side in each patient. The mandibular body and ramus were smaller on the affected side than on the unaffected side. Lateral cephalogram analysis showed that the patients tended to have steep mandibles, large gonial angles, and a slightly convex facial structure. The affected side/unaffected side ratio of the mandibular body and ramus correlated with SNB, ANB, convexity, and mandibular plane. The difference in dental development between the affected and unaffected sides was significant at the mandibular molars and the mandibular canine. Conclusions : This study demonstrates a correlation between lateral and frontal measurement parameters in patients with HFM. The data also showed delayed calcification in the mandibular molars on the affected side.

Change of lip and occlusal cant after simultaneous maxillary and mandibular distraction osteogenesis in hemifacial microsomia

BACKGROUND

The purpose of this study was to investigate the lip and occlusal cant changes in hemifacial microsomia (HFM) cases after simultaneous maxilla and mandibular distraction osteogenesis (DO) of the mandible.

PATIENTS AND METHODS

Retrospective analysis of all HFM cases at Balaji Dental and Craniofacial Hospital were performed. Patient of either gender with all medical imaging records and pre and post-operative (6 months) facial photographs in natural head position were included in the study. The lip cant change was assessed by the angle of each labial commissure and the bi-pupillary reference line. The line joining the frontozygomatic unions and a parallel line is drawn at the level of anterior nasal spine. The occlusal plane is then traced. A vertical line is traced perpendicular to the frontozygomatic union. The deviation of the occlusal plane from the horizontal is measured as the occlusal cant and a change, between pre and post-operative records was considered as the angle and linear measurements.

RESULT

With the linear measurement, the mean change in occlusal cant was 7.18 ± 1.47 mm while for the mean change in lip cant was 3.31 ± 0.52 mm (P = 0.120). For the angular measurement, the mean angle change in occlusal cant was 13.86 ± 2.69° and mean change in angle of lip cant was 8.54 ± 0.7° (P = 0.01).

DISCUSSION AND CONCLUSION

For type1HFM, DO corrects the occlusal and lip cant. In present study, the lip cant change relative to occlusal cant change was 47.54 ± 10.71% in linear measurements while for angular measurements it was 63.19 ± 10.07% (P = 0.476; Pearson's correlation coefficient = -0.241).

Dental development in hemifacial microsomia

Hemifacial microsomia (HFM) is a congenital disorder marked by facial asymmetry. Whether facial asymmetry accounts for asymmetrical dental development is unknown. There are few data on dental development relative to mandibular development or severity of HFM, or on development over time. We hypothesized that when mandibular development was severely disturbed, local dental development was also affected. We compared dental development scores between affected and non-affected mandibular sides in patients with HFM (n = 84) and compared these data with those collected from Dutch control children (n = 451). Logistic functions were constructed for dental age over time for all four Pruzansky/Kaban types. The results showed a tendency toward delayed dental development in Pruzansky/Kaban types IIb and III at younger ages. The temporary delay of tooth formation in patients with severe forms of HFM and the distribution of agenic teeth suggest an interaction between mandibular and dental development.

Sulfotransferase Ndst1 is needed for mandibular and TMJ development

Heparan sulfate proteoglycans (HS-PGs) regulate several developmental processes, but their possible roles in mandibular and TMJ formation are largely unclear. To uncover such roles, we generated mice lacking Golgi-associated N-sulfotransferase 1 (Ndst1) that catalyzes sulfation of HS-PG glycosaminoglycan chains. Ndst1-null mouse embryos exhibited different degrees of phenotypic penetrance. Severely affected mutants lacked the temporomandibular joint and condyle, but had a mandibular remnant that displayed abnormal tooth germs, substandard angiogenesis, and enhanced apoptosis. In mildly affected mutants, the condylar growth plate was dysfunctional and exhibited thicker superficial and polymorphic cell zones, a much wider distribution of Indian hedgehog signaling activity, and ectopic ossification along its lateral border. Interestingly, mildly affected mutants also exhibited facial asymmetry resembling that seen in individuals with hemifacial microsomia. Our findings indicate that Ndst1-dependent HS sulfation is critical for mandibular and TMJ development and allows HS-PGs to exert their roles via regulation of Ihh signaling topography and action.

Hemandibular Hypoplasia Successfully Treated with Functional Appliances: Is it Truly Hemifacial Microsomia?

The literature contains a number of case reports on successful orthopedic treatment of hemifacial microsomia (HFM), with surprising changes in the morphology of the condyles. All of these reports regard patients who have substantially no soft tissue involvement but only severe mandibular ramus and condyle deformities. A number of cases with unexpectedly similar phenotypes diagnosed as HFM are described. The authors suggest that it is possible that all of these cases might be misdiagnosed traumatic injuries of the condyle, which present a normal functional matrix and, therefore, with growth and with the help of functional stimulation, tend to grow toward the original symmetry.

Mandibular distraction osteogenesis in hemifacial microsomia: long-term follow-up

AIM

Prospective, longitudinal, clinical long-term follow-up study of a homogeneous sample of children affected by hemifacial microsomia and treated by mandibular distraction osteogenesis.

MATERIAL

Eight patients affected by types I and II hemifacial microsomia were operated on at an average age of 5.6 years with an average follow-up of 5.8 years.

METHODS

Vertical changes were measured on postero-anterior cephalometric and panoramic radiographs taken sequentially.

RESULTS

Angular changes of the infraorbital and nasal floor planes were not significant, showing that distraction osteogenesis starting after 5 years of age did not influence the maxillary skeletal base. Occlusal (plane) cant was reduced by 7 degrees on average following distraction osteogenesis, showing good dentoalveolar plasticity. Mandibular vertical changes showed a gradual return of the asymmetry, with growth in all patients (the ratio between affected and non-affected rami returned by 77% of the correction obtained by means of distraction 5 years postoperatively).

CONCLUSION

Although aesthetic and psychological advantages of distraction osteogenesis are well accepted it should only be applied after careful patient selection and honest explanation of the long-term recurrence by genetically determined craniofacial growth patterns.

Hemifacial microsomia and treatment options for auricular replacement: A review of the literature

STATEMENT OF PROBLEM

Although surgical reconstruction is the treatment of choice for auricular deformities that result from hemifacial microsomia, the implant-retained auricular prosthesis must be considered when surgical reconstruction is not possible. The competent and successful practitioner should be knowledgeable of the nature of this congenital disease.

PURPOSE

This article reviewed the first and second branchial syndrome, treatment approaches, and potential advances in surgical and prosthetic rehabilitation for patients with hemifacial microsomia.

CONCLUSION

Advantages and disadvantages of autogenous and alloplastic ear reconstructions are discussed. New research initiatives, such as tissue engineering and fabrication of auricular prosthesis by CAD/CAM, offer the potential for improved treatment for the future treatment of hemifacial microsomia.

Effect of early orthopedic intervention on hemifacial microsomia patients: an approach to a cooperative evaluation of treatment results

The purpose of the present study was to analyze the effects of early orthopedic intervention in patients with hemifacial microsomia, clinically as well as radiologically, by computed tomographic examination to assess soft and hard tissue temporomandibular joint changes. Five patients, one with mandibular dysostosis, one with otomandibular dysostosis, two with Goldenhar syndrome, and one with a surgically revised fibroma of the right mandible that was reconstructed by a costochondral graft, were treated by means of an activator functional appliance. During functional appliance treatment, all patients showed improvement of function and occlusion, and facial asymmetry was reduced. Spiral computed tomographic examination before and during treatment provided data on the bony and muscular deficiencies. The volume and density of the lateral pterygoid muscle was measured with the standard computed tomography software. Evaluation of soft and hard tissue conditions before treatment has shown that the most important factor "lack of soft tissues" can be compensated by excellent cooperation during functional therapy. Pretreatment volume of the affected lateral pterygoid muscle in all patients was significantly smaller than on the unaffected side. In three patients, volume measurements between 4 and 8 years demonstrated that the lateral pterygoid muscle on the affected side had a third, less than a third, and a fifth of the volume of the unaffected side. Although increase, stability, and decrease of the ratio of left and right condylar dimension, muscular volume, and density were found, long-term prognosis cannot be given in the cases with extreme muscular deficiencies after cessation of growth. Prepubertal orthopedic treatment success is a desirable and feasible presurgical or nonsurgical treatment goal for the interdisciplinary team approach. From a study of the pathologic, we learn much about the normal.

Hemifacial microsomia: extraoral appliance for the early treatment of an infant. Literature review and case report

In this report a description of the different features of hemifacial microsomia is given and a new way of early treatment of concomitant respiratory problems is presented. An extraoral appliance was developed for the treatment of an infant affected with this syndrome. The purpose was to temporarily minimize the child's repeated respiratory disturbances, which were probably caused by glossoptosis, until an autologous costochondral graft in the mandibular ramus could be performed. An improvement of respiration, of facial asymmetry and even a stimulation of mandibular growth was observed. It is claimed that the use of this appliance can help to avoid tracheotomy in many severe cases of uni- or bilateral facial microsomia with glossoptosis and apnea. This treatment should be considered as temporary until the general condition of the patient has improved and grafting is possible.

Growth changes and orthodontic treatment in a patient with condylolysis

A patient with acquired bilateral degeneration of the mandibular condyles was treated orthodontically. The flattening of condyles and the shortening of the ramus began at adolescence. The facial profile changed to a convex type, with a marked mandibular retrognathia and severe Class II malocclusion. The cause seems to be due to a condylolysis of the mandible.

Data and patterns of transverse dentofacial structure of 6- to 15-year-old children: a posteroanterior cephalometric study

The aims of the present cross-sectional investigation were to provide normative data of selected dentofacial posteroanterior cephalometric measures and to describe the patterns of transverse dentofacial structure. The material comprised the P-A cephalograms of 588 Austrian schoolchildren (157 girls and 431 boys, who were 6 to 15 years old). All subjects were healthy, presented various types of occlusions, and did not receive orthodontic or orthopedic therapy. In studying the P-A cephalograms, 8 linear and 2 angular variables, as well as 10 ratios were used. The results of the study revealed that all skeletal widths and all ratios representing relations between the various breadths of the facial skeleton and the interorbital width demonstrated an increase when the measurements at the initial and final ages of 6 and 15 years, respectively, were compared. However, the maxillary intermolar width during the period from 9 to 12 years did not present any increase, and the mandibular intermolar width remained approximately the same during the whole observation period. The transverse dentoalveolar relationship in the incisal region remained very symmetric during aging. The standard deviations of most cephalometric variables were small when they were compared with their corresponding mean values. The present data are of value for the diagnosis of various types of dentofacial anomalies, for monitoring growth of persons or groups of corresponding age and race, and for comparison with other studies.

The three-dimensional cephalogram: theory, technique, and clinical application

The Broadbent-Bolton cephalostat produces intrinsically three-dimensional information about cranial form. Yet in the clinical setting, this information has been used primarily two dimensions at a time in the separate study of lateral or posteroanterior cephalograms. In this article we demonstrate an expedient use of existing cephalostat-based data sets to derive certain analyses of three-dimensional form. The technique is essentially the same as that of the Broadbent-Bolton "Orientator," an exploitation of the geometry of the cephalostat to simulate stereophotogrammetry. The three-dimensional method supports the usual biometrics of landmark locations, and takes advantage of a normative data base that is suited for semiautomatic analysis of syndromic data. The principal drawback of the method is its inability to represent curving form in three dimensions. However, in comparison with computed tomography (CT), it involves low radiation dose, is simpler to obtain, has an available normative data base, and is more practical for quantitative or long-term serial analysis.

The effect of treatment with functional appliance on a pathologic growth pattern of the condyle

Hemifacial microsomia causes asymmetry of the face frequently known to progress throughout the postnatal development if not submitted to any kind of treatment. According to the theoretic basis for treatment of hemifacial microsomia as presented by Harvold and associates, generation of the right muscle-bone interaction constitutes the necessary precondition for the bone apposition that produces facial symmetry. This theory was the basis for the treatment of three patients with abnormal condyles, one suffering from hemifacial microsomia, one patient with a unilateral condylar fracture followed by displacement and secondary resorption of the condyle, and one patient with bilateral loss of condylar cartilage as a result of trauma. The patients were treated with an activator a.m. Harvold, and the treatment results analyzed radiographically and clinically. The results demonstrated clearly that generation of an altered muscle balance is possible even though hemifacial microsomia patients suffer from absence of normal muscles--that is, normal functional matrix as well as absence of normal condyle--and that bone apposition required for establishment of symmetry can be achieved if the right microenvironment is established. It was, however, also obvious that treatment should be initiated as early as possible because the treatment result was dependent on both the timing and the cooperation of the patient.

Basilar multiplane cephalometric analysis

This article presents a method of cephalometric tracing and analysis using the basilar view cephalogram and discusses its role in diagnosis and treatment planning. Landmarks and structures found in each of three separate basilar planes are defined and instructions for tracings are presented. The analysis is applied to the study of orbital hypertelorism, craniofacial synostosis, and hemicraniofacial microsomia. The multiplane tracing technique is demonstrated to provide a three-dimensional concept of deformities in the craniofacial skeleton. A method to determine an anteroposterior midline construct from structures in the cranial base is described. As is practiced with the lateral cephalogram, presurgical tracings of the basilar film may be manipulated to simulate the skeletal changes anticipated in surgery.