Use of Neuroanatomic Knowledge and Neuronavigation System for a Safe Anterior Petrosectomy

Ana Flores-Justa,José María Santin-Amo,Matias Baldoncini,Amparo Saenz,Alice Giotta Lucifero,Juan F Villalonga,Alvaro Campero,Sabino Luzzi

doi:10.3390/brainsci11040488

Abstract

Introduction: The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery. Drilling of the anterior part of the petrous bone during the anterior transpetrosal approach involves the risk of injury of the cochlea, superior semicircular canal, internal carotid artery, and internal auditory canal. A thorough understanding of the microneurosurgical anatomy of this region is mandatory to execute the transpetrosal approaches, decreasing the risk of complications. The aim of this study is to describe the anatomical structures of the petroclival region, highlighting the importance of neuronavigation for safe performance of the anterior transpetrosal approach. Methods: Three adult cadaveric human heads were formalin-fixed and injected with colored silicone. They underwent an axial 1 mm slab CT scan, which was used for neuronavigation during the surgical approaches. The anterior petrosectomy was performed with the aid of neuronavigation during the drilling of the petrous bone. The surgical management of a patient harboring a petroclival meningioma, operated on using an anterior transpetrosal approach, was reported as an illustrative case. Results: The anterior petrosectomy was completed accurately with wide exposure of the surgical target without injuring the cochlea and other structures in all three cadaveric specimens. In the surgical case, no approach-related complications occurred, and a gross total resection of the tumor was achieved. Conclusions: Deep knowledge of the location and relationships of the vital elements located within the temporal bone, along with the use of neuronavigation, are the key aspects to perform the anterior transpetrosal approach safely, reducing the risk of complications.

Highlights

The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery
Subperiosteal dissection of the temporalis muscle allowed skeletonizing the squamosal part of the temporal bone and the posterior root of the zygoma
Neuronavigation during the anterior petrosectomy was successfully performed in all the specimens, and the surgical case demonstrated its clinical effectiveness

Summary

Introduction

The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery. The approach-related morbidity is non-negligible, especially for tranpetrosal ones, including the risk of cerebrospinal fluid fistulas, facial nerve palsy, deafness, facial anesthesia, and vascular injures [7,9,10,11] This aspect is probably among the main reasons why a number of surgeons are reluctant to use the transpetrosal corridors, recommending alternative approaches for petroclival meningiomas, trigeminal schwannomas, or basilar apex aneurysms. The surgical routes directed through the petrous bone are to be considered invasive only for the bone, since their correct execution involves a complete sparing of the neurovascular structures They permit surgeons to avoid a fixed brain retraction in most cases and allow for better illumination of the surgical field. Perfect knowledge of the anatomy of the middle cranial fossa is paramount for performing the anterior transpetrosal approaches and for concomitantly reducing the risk of complications

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