Anatomical Study of the Prominences on the Posterior Wall of the Maxillary Sinus: Clinical Implications
Background: Endoscopic endonasal approaches to the pterygopalatine fossa have become more frequent with the popularization of control of the terminal branches of the internal maxillary artery for epistaxis and the advent of transpterygoid approaches for endoscopic skull base surgery. Endoscopic identification of superficial landmarks on the posterior wall of the antrum help would help to predict the anatomical position of deeper structures within the pterygopalatine fossa.
Goal: To describe the incidence of important prominences on the posterior wall of maxillary sinus, ascertain their origin and their clinical relevance.
Methods: An anatomical study was performed on 18 adult cadaveric specimens. Middle meatal antrostomies were performed via an endoscopic endonasal approach to expose the posterior wall of maxillary sinus. Subsequently, we noted and recorded the presence or absence, location, number, and laterality of prominences on the posterior wall of maxillary sinus. After removing the bony posterior wall of the maxillary sinus, we ascertained which structure in the pterygopalatine fossa corresponded to the surface markings.
Results: Two prominences (P1 and P2) were identified among 18 specimens. P1 was an elongated prominence extending from the upper part of the PWMS to the inferior orbital wall and corresponded to the infraorbital nerve (IFN). P2 was located at the middle part of the PWMS, below P1, and corresponded to the IMA. P2 was always located medial side to a vertical drop line starting where P1 connected to the PWMS. The incidences of P1 and P2 were 41.7% and 22.2% respectively.
Conclusions: This is the first study to define the prominences on the posterior wall of maxillary sinus from an endoscopic perspective. Findings of this research have clinical significance as these landmarks are useful during the ligation of the IMA or its branches for refractory epistaxis and for surgery of tumors of the sinonasal tract pterygopalatine fossa and skull base.