Mini-Invasive Endoscopic Approaches to the Maxillary Sinus Floor: A Comparative Anatomical Study

While middle antrostomy (MA) is the most common approach to the maxillary sinus (MS), it is known for not allowing to fully inspect the whole MS, especially in its inferior and anterior portions. To overcome this limitation, alternative approaches have been proposed, such as inferior antrotomy (IA) and canine fossa accesses (CFA).

Given the lack of studies on the MS floor visualization with different accesses, our study aims, in a cadaver lab setting, to systematically compare three different approaches (MA, IA and CFA) in these regards.

Eight cadaver heads, previously submitted to CTscan, were prepared inserting fixtures corresponding to teeth 2, 4, 6, 11, 13 and 15 and into the canine fossae. Three approaches were prepared: a wide MA, an IM and a CFA. We endoscopically evaluated, for each specimen, side, access type and scope angle (0°, 30°, 45°, and 70°), which fixtures were visible on the maxillary sinus floor and whether the canine fossa fixture was visible (MA and IA only).

IA allowed to visualize all fixtures in nearly all cases (14/16 with 70° endoscope), while MA showed poor visualization results (3/16 with 70° endoscope); CFA failed to gain full visualization in most specimens (7/16 with 70°endoscope). Such difference was statistically significant. MA proved unable to visualize the canine fossa fixture in most cases while IA showed excellent possibilities. All differences were statistically significant (p < .001, Mcnemar's test).

Our data show that the IA grants a statistically significant superior surgical field vision when compared to MA and CFA, though in vivo validation of these results is still required.