Microsurgical treatment of intracanalicular vestibular schwannomas.

Early treatment of intracanalicular vestibular schwannomas (IVSs) may be advisable because their spontaneous course will show hearing loss in most cases. Advanced microsurgical techniques and continuous intraoperative monitoring of cranial nerves may allow hearing preservation (HP) without facial nerve damage. However, there are still controversies about the definition of HP and the best surgical approach that should be used. In this study, we reviewed the main data from the recent literature on IVS surgery and compared hearing, facial function and complication rates after the retrosigmoid and middle fossa approaches, respectively. The results showed that the average HP rate is approximately 45% after IVS surgery whatever the surgical route. HP varied widely depending on the audiometric criteria that were used for definition of serviceable hearing. There was a trend to show that middle fossa approach offered a better quality of postoperative hearing (not statistically significant), whereas the retrosigmoid approach offered a better facial nerve preservation and fewer complications (not statistically significant). We believe that the timing of treatment in the course of the disease and selection between radiosurgical versus microsurgical procedure are key issues in the management of IVS. Once open surgery has been decided, selection of the approach mainly depends on individual anatomical considerations and experience of the surgeon.