Morphometric evaluation and clinical implications of the greater palatine foramen, greater palatine canal and pterygopalatine fossa on CBCT images and review of literature.

Abstract

The pterygopalatine fossa (PPF) infiltration is performed to reduce blood flow during endoscopic sinus surgery and septorhinoplasty, as well as to control posterior epistaxis and provide regional anesthesia in dental procedures. PPF infiltration performed with consideration of the morphometrics of greater palatine foramen (GPF), greater palatine canal (GPC) and PPF would increase the success of the procedure and reduce the risk of complications. The aim of this study is to investigate the GPF, GPC, lesser palatine foramen (LPF), lesser palatine canal (LPC) and PPF morphology via the images obtained by CBCT, to provide information for interventional procedures. GPF, GPC, LPF, LPC and PPF were morphometrically evaluated retrospectively in CBCT images of 75 female and 75 male cases by Planmeca Romexis program. The 19 parameters were measured on these images. These parameters were evaluated statistically. The comparison of these parameters by genders revealed significant differences in distances between GPC-PC, PC-IOF, LPC-GPF, GPF-MS in the coronal and transverse planes, the distance between GPF and the occlusal plane of the teeth, GPF-PNS, GPF-IF and TD-GPF, and in the area of GPF. The number of LPF was found ranging from 1 to 5. Our results may help to insert to needle properly for application of maxillary nerve block with a high success rate and minimal complication. We recommend that the needle should be inserted 14-15mm lateral to the midsagittal plane, 19-20mm over the occlusal plane of the teeth and on the same line with the third molar teeth. For PPF infiltration through the GPF, the needle should be pushed forward 28mm upward at 66° angle on the transverse plane and 14°-15° angle on the vertical plane.