Long-term vestibulocochlear functional outcome following retro-sigmoid approach to resection of vestibular schwannoma

The objective of this study was to evaluate long-term vestibulocochlear functional outcomes of patients operated for unilateral vestibular schwannoma via the retro-sigmoid approach. Patients who underwent vestibular schwannoma resection via retro-sigmoid approach between 2004 and 2008 at our institution, without prior surgical or radio-surgical therapy were considered to be eligible for this study. Preoperative auditory and vestibular symptoms were assessed retrospectively. Postoperative symptoms were prospectively assessed using a standardised questionnaire, pure tone audiometry, video-oculography, and rotary chair testing. Out of a total of 203 patients, 120 were eligible for this study, of whom 64 responded to follow-up requests and could be enrolled. Serviceable hearing was reported in 42 patients (66 %) preoperatively and was maintained in 18 (43 %) postoperatively. While no significant change in rate of tinnitus and balance impairment between pre- and postoperative periods was detected, vertigo decreased significantly (40 to 28 %, p < 0.001). Postoperative video-oculography demonstrated vestibular paresis in 80 %. Rotary chair testing demonstrated normal or central compensation in 84 %. Absence of central compensation was associated with postoperative balance disturbance (p = 0.035). Increasing tumour size and patient age, also decreasing quality of preoperative hearing were independent factors predictive of a postoperative non-serviceable hearing (p = 0.020, p = 0.039 and p = 0.002, respectively). Resection of vestibular schwannoma via the retro-sigmoid approach is associated with improvement in postoperative vertiginous symptoms. Absence of central compensation leads to increased postoperative balance disturbances. Preservation of serviceable postoperative hearing is associated with good preoperative hearing status, younger age, and smaller tumours.