Endoscopic Multiportal Subtemporal Approach to Middle Cranial Fossa Floor

 

Introduction: Subtemporal keyhole approaches have been studied and employed to access the middle cranial fossa (MCF) for the treatment of encephaloceles, management of skull base defects, and tumoral resection. This approach represents a less-invasive technique than a traditional craniotomy and prevents excessive temporal lobe retraction. In this study, we present the endoscopic multiportal subtemporal approach to the MCF as a minimally invasive alternative.

Objective: The aim of this study is to investigate the feasibility and limitations in the clinical setting, specifically at repairing middle cranial fossa defects.

Methods: This study was performed on three alcohol-preserved, latex-injected cadaveric specimens. The procedure begins by demarcating two incisions sites anteriorly to the tragus and along the supramastoid crest. Once the incisions are carried down to the bone, the squama of the temporal bone is exposed and two burr holes are performed. Temporal dura is gently dissected from the MCF floor with the posterior petrosal edge as posterior limit and the GSPN as anteromedial extent.

Results: This multiportal approach allows wide exposition of three key sites for the treatment of MCF defects: the mastoid antrum roof, the arcuate eminence, and the tegmen tympani. It also permits appropriate maneuverability for surgical instruments which proves to be not inferior to other described keyhole techniques. Flaws of the procedure are the limited lateral visualization and the limited possibility to insert rigid reconstruction grafts which often are required for the repair of large defects.

Conclusion: The presented technique obviates some of the inconveniences of the classical microscopic craniotomy approach to the MCF floor. However, it may not be well-suited for large defects which may often require a rigid reconstruction technique. Nonetheless, temporal lobe retraction is significantly reduced and massive temporal muscle detachment is avoided, decreasing the risk of chewing discomfort after surgery. In addition, this technique presents the main difference from other endoscopic published procedures for MCF floor exploration that being the use of a two-hole approach which significantly increases both the range of surgical exposition and the capability to maneuver surgical instruments.

Publication History

Article published online:
15 February 2022

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