Comparative anatomical study on the role of zygomatic osteotomy in the extradural subtemporal approach to the clival region, when less is more.

Purpose: A great concern in performing the extradural subtemporal approach (ESTA) is the evaluation of the actual advantage provided by zygomatic osteotomy (ZO). Complications related to zygomatic dissection have been widely reported in the literature, making it of paramount importance to balance the actual need to perform it, against the risk of maneuver-related morbidity. Authors comparatively analyze the putative advantage provided by ZO in the ESTA in terms of anatomic exposure and surgical operability. Technical limits and potentials are critically revised and discussed.

Methods: A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability.

Results: ZO was found to provide a weakly significant improvement in the surgical angle of attack (p value 0.01) (mean increase 3°). Maneuverability arch (MAC) increase related to ZO did not reach statistical significance (p value 0.09) (mean increase 2°). The variations provided by MAC increase on the conizing effect (CE) did not lead to an actual advantage in the real surgical scenario, modifying the vision area (VA) in terms of reduction of central vision area (CA) in favor of an increase of peripheral vision area (PA) only in the most caudal part of the surgical field. Ultimately, ZO did not influence the overall OS, scoring both ESTA-ZO and ESTA-ZO 2 out of 3.

Conclusion: In the ESTA, ZO does not provide an actual significant advantage in terms of surgical operability on clival and paraclival areas.