Microsurgical anatomical study of the frontotemporal-zygomatic arch approach to the superior petroclival region.

The aim of this study was to explore the microsurgical anatomy of the superior petroclival region, and thus provide an anatomical basis for operative approaches. The frontotemporal-orbitozygomatic approach was performed on 20 sides of 10 adult cadaver heads. In comparison to the range of the exposure with the removal of the anterior clinoid process, posterior clinoid process and part of the tip of the petrous bone, we measured the neurovascular course and their relation to the superior petroclival region. We found that the trochlear nerve goes through the edge of the tentorial marginal branch, taking 5.42 mm (4.26-6.96) away from the ophthalmic nerve. Exposing the arteria basilaris, above the middle piece the length of exposure is 15.52 mm (14.22-16.70), resulting in the posterior cerebral artery and the front part of the midbrain being completely exposed. There is little exposure on the front part of the pons and midbrain with a length of 5.6 mm (4.38-6.82). Removing the partial petrosal bones, the inferior segment of the basal artery is exposed, while 4 other nerves cab also be observed: Cranial, abducens, facial and vestibulocochlear. The frontotemporal-zygomatic arch approach can clearly expose the superior petroclival region. Obtaining more information on the relationship between the location of these structures, is therefore helpful in improving the safety and success of surgery in this region.