Introduction: This study aims to assess the usefulness of endoscopy during microvascular decompression (MVD) procedures for idiopathic trigeminal neuralgia (TN) and hemifacial spasm (HFS).
Methods: Between January 2010 and December 2011, 93 MVD procedures were performed (76 TN, 17 HFS). The operative technique always included a careful examination of the whole nerve course to identify possible sites of vascular compression. The visualization techniques used were: fully microscopic in 59 (63.5%) cases and fully endoscopic in 8 (8.5%) cases. In the remaining 26 (28%) cases, when the conflict was not clearly identified under microscopic view or it was not certainly resolved, the endoscope was then introduced, thus using a combined microscopic/endoscopic technique.
Results: In this series no surgical related neurovascular complications occurred. A neurovascular conflict was found in 86 (92.5%) cases. The microscope or the endoscope alone were able to show the conflict in all 67 cases. In the 26 microscopic endoscope assisted cases, the endoscope revealed 10 conflicts previously not clearly visible with the miscroscope and confirmed a complete conflict resolution in 9 cases. Seven patients had no intraoperative evidence of neurovascular conflict. During combined procedures, the introduction of the endoscope under microscopic magnification decreases the chances of damaging the neurovascular structures of the cerebello-pontine angle. This increases the confidence of the surgeon with the endoscopic technique, shortening the learning curve with this tool. Conversely, the fully endoscopic approach requires more experience and training; sometimes it is also necessary to do a wider craniotomy to allow enough room for the endoscope and for surgical instruments.
Conclusions: MVD under microscopic view remains the treatment of choice for neurovascular conflicts in the cerebello-pontine angle. The endoscope is a useful adjunctive imaging tool in confirming neurovascular conflicts identified by the microscope, revealing conflicts missed by the microscopic survey alone and verifying adequate nerve decompression.
Patient Care: In cases when the neurovascular conflict is not clearly identified under microscopic view or the surgeon is not fully convinced about conflict resolution, endoscopy can be helpful, thus resulting in improved success rate of the procedure.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify in which cases and when the endoscope can be used. 2) Understand the advantages and disadvantages of using the endoscope in such a delicate region.