Microvascular decompression of cochlear nerve for tinnitus incapacity: pre-surgical data, surgical analyses and long-term follow-up of 15 patients.

The level of success of neurovascular decompression in ponto-cerebellar angle for hemifacial spasm and trigeminal neuralgia has already established the reality of the pathology to explain such symptoms. However, cochlear nerve compression syndrome by vascular loop is still a controversial topic. We have performed a retrospective cases review with long-term follow-up (5-7 years) concerning the results of microvascular decompression surgery of the cochlear nerve via an endoscopy assisted retrosigmoid approach on 15 patients suffering from unilateral incapacitating tinnitus with abnormal auditory brainstem response and an offending vessel on magnetic resonance imaging. During the surgery, a vascular compression was found on every patient. In a long-term follow-up, 53.3% (8 cases) of our tinnitus cases improved and 20% (3 cases) of them were completely cured. The ABR returned to normal in all patients who had good clinical results (diminished or disappeared tinnitus). When a vertebral artery loop (5 cases) was concerned we obtained 80% of good clinical results. No one showed amelioration or sudden aggravation of their hearing. Three cases required surgical correction of cerebrospinal fluid leak and one case developed spontaneously regressive swallowing problems. Such microvascular decompression surgery of the cochlear nerve appears to be successful in treating incapaciting tinnitus in particular when a vertebral artery loop is observed. Therefore, in such a case, one might recommend neurovascular decompression surgery, keeping in mind that the complications of this surgery should be minimized by a careful closure of the retrosigmoid approach. In order to ensure a better selection of patient more accurate cochlear nerve monitoring and functional MRI should be a promising assessment.