Anatomical study using cadavers for imaging of life-threatening complications in Le Fort III distraction.

BACKGROUND: Few reports describe devastating complications with conventional Le Fort III osteotomy; however, life-threatening complications have been reported occasionally with Le Fort III distraction. An anatomical study using cadaveric Le Fort III osteotomy models was performed to investigate the causes of untoward fractures that might induce devastating complications. METHODS: The study sample consisted of 30 cadavers (60 sides). Specimens were separated into six groups depending on whether osteotomy of the lateral maxillary wall from the inferior orbital fissure to the pterygomaxillary junction (procedure A) and separation of the pterygomaxillary junction (procedure B) were performed completely, incompletely, or not at all. All osteotomy and fracture lines including the skull base and orbit were examined by computed tomography and direct observation. The separation or fracture type of the pterygoid plate of the sphenoid bone was categorized into four groups: ideal separation, low-level fracture, high-level fracture, and others. The frequency of each type of pterygoid plate fracture between controls and each group was compared. RESULTS: High-level fractures occurred more frequently in groups with intact pterygomaxillary junctions. All specimens with untoward fractures of the sphenoid bone leading to the skull base or carotid canal accompanied high-level pterygoid fractures, occurring in groups without sufficient pterygomaxillary separation. An extraordinary orbital fracture was observed when neither procedure A nor procedure B was performed. CONCLUSIONS: Precise separation of the pterygomaxillary junction is primarily of importance for preventing devastating complications of Le Fort III osteotomy and Le Fort III distraction. Osteotomy of the lateral maxillary wall is also necessary to minimize this risk.