Quantitative Anatomic Study of the Minipterional Craniotomy in the Paraclinoid Region: Benefits of Extradural Anterior Clinoidectomy

Abstract

Background: Extradural anterior clinoidectomy (eAC) via the minipterional craniotomy (MPT) approach (MPT+eAC) has been recently introduced to the neurosurgical armamentarium to improve access to anterior and middle fossa skull base structures using a minimally invasive approach. However, the effect of extradural clinoidectomy on surgical exposure with the minipterional approach has not been evaluated. Moreover, the effect of eAC on surgical maneuverability has not been established for either traditional pterional or minipterional craniotomy. We sought to illustrate the microsurgical anatomy of the MPT+eAC and to evaluate the effect of eAC on surgical exposure and maneuverability. Methods: The area of exposure, area of surgical freedom, and maneuverability score for the MPT approach and MPT+eAC were compared in 5 cadaveric heads. Results: Compared with the MPT approach, the MPT+eAC enlarged the area of exposure approximately twofold (93 cm2 vs. 184 cm2; P < 0.001). All targets considered in the paraclinoid region, including the posterior communicating artery origin, prechiasmatic region, and ophthalmic artery origin, showed an increase in surgical freedom and maneuverability after performing eAC. Targets remote from the clinoid such as the internal carotid bifurcation were not affected. Conclusions: MPT+eAC offers a larger area of exposure and greater surgical freedom and maneuverability at the paraclinoid region using this minimally invasive approach.