Endoscopic Surgery of the Cerebellopontine Angle: Barriers to Adoption

Introduction: Endoscopic- assisted surgery of the cerebellopontine angle (CPA) has been utilized for over a decade, but unlike the skull base surgeon's experience in the transnasal route, transition to a fully endoscopic procedure within the CPA has not gained widespread acceptance. This study reviews a single surgeon's experience (J. Y. K. L.) with an emphasis on endoscopic versus microscopic surgical techniques in the CPA.

Methods: This is a retrospective review of all surgical procedures performed by a single neurosurgeon (J. Y. K. L.) from 2006 to 2014 (MVD) and from 2011 to 2014 (acoustic neuroma).

Results: Over the time period from 2006 to 2014, 265 microvascular decompressions were performed through a retrosigmoid route, (89% for trigeminal neuralgia and the remainder for hemifacial spasm and other indications). Of the MVD procedures, 127 procedures (48%) were performed with endoscopic visualization only (without a microscope). Over the past 2 years, more than 95% of MVD procedures have been performed purely with an endoscope, representing the gradual transition from microscopic to fully endoscopic.

Endoscope adoption for acoustic neuroma resection demonstrates a different pattern of adoption as compared with MVD. Over a 3-year time period, 83 acoustic neuroma resections were performed through retrosigmoid (79%) or translabyrinthine (21%) route. About 16% of procedures were performed with the use of the endoscope, and in all the cases the endoscope was used as an adjunct—endoscope assisted—instead of fully endoscopic. Specific limitations of adoption of the fully endoscopic approach for tumor resections as compared with MVD include the following: tumor bleeding, difficulty in keeping endoscope clean during drilling of the IAC, instrument clash, and learning curve by surgical team members.

Conclusion: In experienced hands, fully endoscopic CPA surgery offers superb visualization and illumination and is both safe and effective, especially for microvascular decompression. The transition to a fully endoscopic resection of acoustic neuroma necessitates additional experience and steeper learning curve by both ENT and neurosurgical team members. Future adoption of a fully endoscopic cerebellopontine angle surgery will require attention to these specific points.