Fig. 1

Illustration of the principles of microvascular decompression and the cranial nerves in proximity to the surgical area. The anatomical localization of the entry of the cranial nerves into the brainstem and the surgical field of microvascular decompression. The procedure was performed with the patient in a park bench position under general anaesthesia via an approximately 2 × 3 cm retrosigmoid craniectomy. Via a supracerebellar infratentorial approach, the cerebellopontine angle was visualized, and the trigeminal nerve and compressing vessel(s) were identified (Fig. 1). If the superior cerebellar artery was causing the compression, the nerve was alleviated by transposition of the blood vessel towards the tentorium, where it was fixed with Teflon and glue. If the compression was caused by the posterior or anterior inferior cerebellar artery the blood vessel was transposed caudally and fixed with Teflon if possible. If the surgeon was unable to transpose the artery, a piece of Teflon was interposed between the trigeminal nerve and the conflicting artery. If a vein was causing the compression, the vein was either divided to avoid avulsion or if possible, a piece of Teflon was interposed between the trigeminal nerve and the vein. The surgeon preferred not to coagulate veins and in particular sought to preserve the superior petrosal vein. Surgery was performed without the use of neuronavigation or brainstem auditory evoked responses or other neuromonitoring. Cerebellar retraction was not used, and neither were specific relaxation techniques. All procedures were performed microscopically