An anatomic study using three-dimensional reconstruction for pterygopalatine fossa infiltration via the greater palatine canal

The pterygopalatine fossa (PPF) is accessed via the greater palatine canal (GPC) in an attempt to reduce bleeding during paranasal sinus surgery. This study aims to investigate the anatomy of the greater palatine foramen (GPF), GPC, and the PPF, with reference to PPF infiltration using three-dimensional reconstruction of computer tomographic (CT) scan measurements. The CT scans of 50 patients were retrospectively evaluated. The morphology of the GPF, GPC, and the PPF was assessed in a three-dimensional model. The thickness of the mucosa over the GPF was evaluated in the parasagittal plane. The mean length of the GPC was 13.8 ± 2.0 mm, and the mean height of the PPF was 21.0 ± 3.4 mm. The mean angles of the GPC in relation to the hard palate and the PPF were 67.4° ± 6.9° and 159.8° ± 7.1°, respectively. The GPF was 16.2 ± 1.3 mm lateral to the sagittal plane of the posterior nasal spine (PNS) and 6.1 ± 1.7 mm anterior to the coronal plane of the PNS. The mean volume of the PPF was 1039.9 ± 280.0 mm³. The mean thickness of the mucosa overlying the GPF was 10.7 ± 1.8 mm. We recommend that the PNS may be used as the bony landmark to locate the position of the GPF during PPF infiltration. The needle delivering the anesthetic should be bent 25 mm from the tip at a 45° angle, and a 1-ml injection of anesthetic should be administered in adults.