The anatomy of the sphenoid sinus and pterygomaxillary junction region in Le Fort I osteotomy

Purpose: The purpose of this study was to examine the location and morphology of sphenoid sinus, pterygoid plate and great palatine canal at the pterygomaxillary region in Le Fort I osteotomy. Method. The subjects consisted of 144 Japanese patients with jaw deformity patients. Lateral cephalograms and computed tomography (CT) were analyzed for all patients. The measurements of the sphenoid sinus, pterygoid plate and great palatine canal were assessed using 2 bilateral sagittal planes (right and left) involving the great palatine canals and mid-sagittal plane involving ANS and PNS. Results. The subjects were divided into three groups (47 class II female, 62 class III female and 35 class III male). Sphenoid sinus existed on the sagittal plane involving the great palatine canal in 81 of 94 sides (86.2%) in class II female, 85 of 124 sides (68.5%) in class III female and 57 of 70 sides (81.4%) male. The distribution was significant difference (P = 0.0386). There was significant difference in the right maxillary sinus length (ML) between class II female and class III female (P = 0.0049). Ramus inclination in cephalometric measurements was selected as a variable related to the vertical distance between the sphenoid sinus wall and PNS (VDS) by stepwise regression analysis (P = 0.003 right, P = 0.0210 left). Conclusions . These results suggest that the sphenoid sinus exist more frequently recognized close to superior site of the pterygoid plate in class II female. However, the location of the sphenoid sinus at the pterygomaxillary junction region could not be predicted accurately using cephalometric measurements analysis.