Microsurgical And Imaging Anatomy Study Of The Pterygopalatine Fossa

Objective:(1) To study the field of procedure and reliable landmark for endoscopic approach to the pterygopalatine fossa; (2) To investigate the anatomic variations of third portion of the internal maxillary artery and it's branches in endoscopic approach; (3) To observe the anatomy of effect of maxillary nerve and pterygopalatine ganglion on endoscopic surgery; (4) To analyze the present use of different endoscopic of the pterygopalatine fossa; (5) To probe clinical significance of the three -dimensional images of the pterygopalatine fossa . Methods:The bony landmarks of pterygopalatine fossa in 20(40 sides) dry skulls were measured and 15 cadavers(30 sides)of skull were microdissected. The correlative anatomic structure was measured during simulated endoscopic surgery on 15 adult cadaveric specimens. All data were analyzed by SAS. Results:1. The crista ethmoidalis of the perpendicular plate of the palatine bone was located just antero- inferior to the sphenopalatine foramen, and anterior to the lateral posterior nasal arteries. The distances from sphenopalatine foramen to anterior nasal spine,to superior end of inferior and to posterior end of middle turbinate concha were 50.54 + 3.28 mm ,9.99+1.79 mm and9. 51 + 1.88 mm respectively.2. The external diameter of the posterior superior alveolar artery, infraorbital artery, descending palatine artery and sphenopalatine artery were 1. 56 + 0. 32mm, 1. 26 + 0. 22mm, 1. 48 0.27mm and 1. 79 + 0. 34mm respectively.3. The contours of third portion of the internal maxillary artery, may be classified into 4 types:Y, intermediate, T, M. The Y type was found in 7 (23.3%) , intermediate in 10 (33. 3%) ,T in 8 (26. 7%) and M in 5 (16. 7%) in the 30 sides of cadavers.4. The pterygopalatine ganglion was found to be of triangular shape in all specimens. This triangular shape reflects its three principal branches:the vidannerve superomedially, the branch from the maxillary nerve superolaterally, and the palatine nerve inferiorly. The distances from The pterygopalatine ganglion to anterior nasal spine and to lateral nasal wall were 55. 82 2. 58mm and?. 16 1. 54mm respectively.5. The distances from foramen rotundum to anterior nasal spur,superior orbital fissure, optic canal and midsagittal plane are61. 86 3. 67mm, 3. 56 0.75mm, 11.23 1.24mm, 19.95 2.79mm respectively.6. All pterygopalatine fossa structures were indicated clearly and directly at various VR and MPR. There were accuracies in the measurement with cadavers and VR , MPR, both of which had not sighificantly differention(P>0. 05).Conclusion:1. Our investigation indicates that the crista ethmoidalis is a helpful and reliable landmark for endoscopically located sphenopalatine artery and foramen.2. The contours of third portion of the internal maxillary artery, may be classified into 3. Types:Y, intermediate, T, M. it is significance to endoscopic surgery approach to the pterygopalatine fossa and prevention of complication;4. Our investigation indicates that the descending palatine artery is a key landmark for endoscopically located sphenopalatine artery.5. The results indicate that the palatine nerve is a important landmark for endoscopic surgery to key out maxillary nerve and vidian nerve;5. We get the scope of the three different surgery. 6. The 3D images of pterygopalatine fossa are helpful in stereotaxy of anatomic structure at surgery.