Endoscopic Anatomy Variation of the Medial Pterygopalatine Fossa Structures and Its Surgical Applications

Objectives: Describe the endoscopic anatomy variability of the medial Pterygopalatine Fossa (PPF) structures during cadaveric dissection, and analyze the relationship of the neurovascular structures in this region. Methods: 20 non-injected fresh cadaveric specimens were dissected bilaterally via the endonasal endoscopic approach.40 medial PPF regions are described. The distances between the vidian canal (VC) and palatovaginal canal (PVC) orifices are measured and the mean length of the PVC is estimated. Also we measured the distances between VC orifice and foramen rotundum (FR) to estimate the risk of maxillary nerve lesion during the transnasal vidian neurectomy. The 3-D relationship between the greater palatine neurovascular bundle (GPB) and the aforesaid structures has been analyzed. Results: The mean distance between PVC and VC orifices equaled 2.6 mm and the mean length of the PVC was 6.4 mm. The mean length of the palatine bone sphenoid process is 7.2 mm, which is always approximately equal to the distance between the GPB and the PVC cranial orifice. The mean distance between the VC orifice and FR is 4.6 mm. Conclusions: Based upon this study, modified “retrograde” approach to the VC orifice from the choanal arch behind the middle turbinate tail via the palatine bone sphenoid process along the PVC is proposed. The peculiarity of this approach is the preservation of the PPF contents and sphenopalatine neurovascular bundle, which are moved aside laterally during the dissection. Further investigation is needed to establish the feasibility of this approach in vivo.