Role of the Extradural Anterior Clinoidectomy to Approach the Paraclinoid Region Using Minimally Invasive Approaches: An Anatomic Study

Background: The eAC is a standard technique that enhances the extradural corridor and provides a broad access to the entire parasellar region, while reducing brain retraction. However, its role in expanding the surgical corridor in minipterional approach has not been addressed yet.

We sought to illustrate the microsurgical anatomy of the MPT + eAC and to evaluate the effect of eAC on surgical exposure and maneuverability along the paraclinoid region.

Methods: Area of exposure, surgical freedom, and surgical maneuverability provided by the MPT and MPT + eAC along the paraclinoid region were compared in six cadaveric heads. The area of exposure was determined by the length and width of a pentagonal-shaped region defining the area of interest within the paraclinoid region. Area of surgical freedom and maneuverability were calculated at 4 points considered to be representative of the paraclinoid region (Optic chiasm, origin of the posterior communicating artery, origin of the ophthalmic artery, and internal carotid bifurcation).

Results: In comparison to the MPT, the MPT + eAC enlarges the area of exposure in the paraclinoid region up to twofold (90 vs. 192 cm², p < 0.001). Likewise, the MPT + eAC afforded a larger area of surgical freedom and better maneuverability at all selected targets in the paraclinoid area (p < 0.05).

Conclusions: The evidence provided in this study establishes that the ACP affords improved surgical exposure and maneuverability when added to the MPT. The MPT offers a less invasive alternative to the traditional pterional or orbitozygomatic approach, while the eAC is a well stablished technique that overcomes some of the previous limitations of the standard MPT, improving surgical exposure and maneuverability within such narrow corridor.