Chapter 13 - Endoscopic Endonasal Approach to Lateral Cavernous Sinus Lesions

Abstract

The cavernous sinus is still one of the riskiest areas of the skull base to be accessed surgically. Endoscopic endonasal approaches (EEA) to the cavernous sinus have become an attractive alternative to open approaches, particularly to address pathology located in the medial cavernous sinus. As all the cranial nerves are located lateral to the Internal Carotid Artery (ICA), any approach to the lateral cavernous sinus has the potential for morbidity. The cavernous ICA is also in risk, and it separates the lateral cavernous sinus from the medial cavernous compartment. The cranial nerves III, IV, V1, and VI area located in the lateral compartment of the cavernous sinus. The abducens nerve runs freely within the lateral cavernous sinus between the ICA and the lateral wall and is the most vulnerable nerve during a resection. The surgical technique involves a transmaxillary, transpterygoid approach in which the vidian nerve is followed endoscopically back to the lacerum segment of the ICA. The entire lateral sphenoid and cavernous sinus can then be visualized and reached surgically. Specialized neuro-endoscopic instruments, cranial nerve monitoring, stereotactic neuronavigation, doppler utilization, and an experienced team of neurosurgeons and otolaryngologists are essential for success. In properly selected patients, this technique can achieve excellent results with a low complication rate. The ventral corridor using the EEA to access the lateral compartment of the cavernous sinus is advantageous in comparison to open approaches since there is no need to dissect in between the cranial nerves to enter it.