Influence of metopic suture fusion associated with sagittal synostosis.

Some patients with sagittal synostosis present with a fused metopic suture. We hypothesize that premature metopic suture fusion consistently and identifiably alters form associated with sagittal synostosis. We previously validated three-dimensional vector analysis as a tool for the study of cranial morphology and used it herein to distinguish between dysmorphologies of isolated sagittal synostosis (ISS) and combined sagittal-metopic synostosis (CSM). Preoperative computed tomographic scans for patients with ISS and CSM were compared with matched normative counterparts. Premature metopic suture fusion was defined by established radiographic criteria. Color-coded point clouds were created for each scan, with color gradient based on patient deviation from normal across the dysmorphic skull. Standard deviation data were evaluated in 7 cranial regions and compared between ISS and CSM. Mean ISS and CSM point clouds were evaluated. Using three-dimensional vector analysis, standard anthropometric data/indices were determined and compared between the 2 groups. Differences in ISS and CSM regional deviations and index measurements were not statistically significant. Mean ISS and CSM representations depicted similar overall morphology. Using accepted criteria for identification of metopic synostosis in CSM, only subtle differences appear between the 2 populations on average. Expected morphologic changes associated with metopic synostosis are present in only a small number of patients with CSM, arguing against our hypothesis, and calling into question the criteria used to identify premature metopic suture fusion. Normal metopic suture fusion occurs for a continuum of time. Our findings suggest that the normal continuum may begin earlier than the literature suggests. In the setting of sagittal synostosis, the influence of metopic suture fusion and treatment is best determined by individual morphologic analysis.

Use of a three-dimensional, normative database of pediatric craniofacial morphology for modern anthropometric analysis.

BACKGROUND: Surgical correction of cranial abnormalities, including craniosynostosis, requires knowledge of normal skull shape to appreciate dysmorphic variations. However, the inability of current anthropometric techniques to adequately characterize three-dimensional cranial shape severely limits morphologic study. The authors previously introduced three-dimensional vector analysis, a quantitative method that maps cranial form from computed tomography data. In this article, the authors report its role in the development and validation of a normative database of pediatric cranial morphology and in clinical analysis of craniosynostosis. METHODS: Normal pediatric craniofacial computed tomography data sets were acquired retrospectively from the Duke University Picture Archive and Communications System. Age increments ranging from 1 to 72 months were predetermined for scan acquisition. Three-dimensional vector analysis was performed on individual data sets, generating a set of point clouds. Averages and standard deviations for the age and gender bins of point clouds were used to create normative three-dimensional models. Anthropometric measurements from three-dimensional vector analysis models were compared with published matched data. Preoperative and postoperative morphologies of a sagittal synostosis case were analyzed using three-dimensional vector analysis and the normative database. RESULTS: Three- and two-dimensional representations were created to define age-incremental normative models. Length and width dimensions agreed with previously published data. Detailed morphologic analysis is provided for a case of sagittal synostosis by applying age- and gender-matched data. CONCLUSIONS: Three-dimensional vector analysis provides accurate, comprehensive description of cranial morphology with quantitative graphic output. The method enables development of an extensive pediatric normative craniofacial database. Future application of these data will facilitate analysis of cranial anomalies and assist with clinical assessment.

Osteocutaneous face transplantation.

BACKGROUND: Facial transplantation has the potential to become a viable option in the treatment of acquired and congenital facial deformities. Transplantation of the bony maxillofacial skeleton with the soft tissues (osteocutaneous face transplantation) has not been performed clinically nor has it been described experimentally in a human cadaver model. METHODS: A mock osteocutaneous face transplant procedure was carried out on a cadaver model. The face was harvested in the subperiosteal plane and included the Le Fort III osseous segment. The allograft was inset by rigid internal fixation and soft tissue approximation. RESULTS: The face transplant procedure was technically feasible. On the basis of this experiment, review of prior investigations, and our experience in craniofacial surgery, the authors have identified 10 topics that present technical challenges specific to osteocutaneous transplantation of the face: customisation of the bony segment, sensory and motor innervation, extra-ocular movements, dentition, mastication, speech and swallowing, airway, vascular considerations, immunologic considerations, and identity issues. CONCLUSIONS: Once further advances in immunomodulatory therapy are made, face transplantation will likely still be reserved for only the most severe facial defects. Defects of such severity will likely include a substantial bony component in need of reconstruction. In addition to the challenges associated with facial allo-transplantation in general, there are many technical challenges associated specifically with osteocutaneous face transplantation. It is necessary to consider and discuss these challenges in anticipation of future advances that may allow composite face transplantation to become safe and clinically efficacious. This modality of transplantation has the potential to provide substantial benefit compared with autologous reconstruction.

A pilot study in sub-SMAS face transplantation: defining donor compatibility and assessing outcomes in a cadaver model.

BACKGROUND: Face transplantation may become a viable alternative in the treatment of patients with severe acquired facial deformity. In this study, the authors investigate morphological compatibility between donor and recipient by assessing chimeric outcomes in a human cadaver model. METHODS: Four faces were harvested from fresh human cadaver specimens in a surgical plane deep to the galea, to the superficial musculoaponeurotic system, and to the platysma. The faces were subsequently exchanged among the four donor crania, simulating full-face transplantations. Eight cranium-face chimera complexes were created and analyzed with standardized photography and with volumetric computed tomographic radiography. RESULTS: Four morphological parameters to consider in determining donor/recipient compatibility were defined: (1) skin color and texture, (2) head size, (3) soft-tissue features, and (4) gender. CONCLUSION: Careful selection of face donors based on compatibility criteria will aid in ensuring that the posttransplant outcome is morphologically similar to the recipient's native face.