Retractorless Retrosigmoid Craniectomy with Endoscopic Assistance to Meckel’s Cave, Technical Video

Background Meckel’s cave involvement in tumors poses a challenge due to their surrounding neurovascular structure and deep location. When tumors of this location need treatment, it is often that radiosurgery is given the strongest consideration due to the difficulty of the open surgical techniques associated with this region. The classic approach to Meckel’s case is anterolateral using a pterional craniotomy. This requires temporal lobe elevation to gain access to the region. The retrosigmoid intradural suprameatal approach involves a retrosigmoid craniotomy with drilling of the suprameatus petrous bone also provides access to the Meckel’s cave. The expanded endonasal endoscopic approach (EEA) also provides anteromedial access to the base of the Gasserian ganglion without brain retraction; however, it is not very commonly used. We present a case of a cerebellopontine angle tumor with Meckel’s cave involvement where endoscopic assistance is useful for tumor resection.

Case Review A 24-year-old man presented a year prior was found to have a large epidermoid tumor in the setting of progressive headaches and right trigeminal neuralgia. The tumor extended from the ambient cistern to the cerebellomedullary cistern and involved Meckel’s cave.

Technical Note/Video Description A retrosigmoid craniectomy was performed. Cranial nerves III, IV, VI, VII, IX, X and auditory brain stem responses were monitored. Once the craniectomy was completed, the dura was opened and thorough arachnoid dissection was completed to allow retraction on the cerebellum. Care was taken to ensure that cranial nerves VII/VIII and IX/X were free. Using ring curettes, the pearly white epidermoid tumor was able to be debulked. After the entire possible tumor was resected with the microscope. At this time, the 30-degree endoscope was used to identify the porus trigeminus. Malleable ring curettes and a malleable suction were used to remove the soft tumor from this location. The patient transiently had loss of hearing, but this returned within 2 weeks after surgery.

Conclusion The retrosigmoid approach is familiar to all neurosurgeons and with the adjunct of an angled endoscope, the posterior Meckel’s cave can be easily reached. This is particularly useful for tumors with soft consistency. The assistance of the endoscope allows Meckel’s cave visualization without additional drilling while still allowing safe resection of tumor from around the trigeminal nerve.