gms | German Medical Science

Objective: After vestibular schwannoma (VS) surgery, a deterioration of facial and cochlear nerve function are common complications. In clinical routine neuroprotective strategies are still missing. A pilot-study (n=30) of prophylactic nimodipine and hydroxyethylstarch (HES) showed a beneficial effect on facial and cochlear nerve functions following VS surgery. An analogously performed prospective phase III trial (n=112) revealed no statistically significant result. However, the risk for postoperative deterioration of hearing was two times lower in the therapy group. Considering the small sample size, the data of both studies were pooled.

Method: The patients of both the monocentric, randomised pilot-study and the randomised multi-centre phase III trial were assigned to two groups. The therapy group (n=70) received parenteral nimodipine (1-2 mg/hr) and HES (hematocrit 30%-35%) from the day before surgery until the seventh postoperative day. The control group (n=72) was not treated prophylactically. Facial and cochlear nerve functions were documented before the operation, during the inpatient care and one year after surgery.

Results: Pooled raw data from both prospective studies was analyzed retrospectively. Intent-to-treat (ITT) analysis revealed a significantly lower risk for hearing loss (class D) twelve months after surgery in the therapy group compared to the control group (OR 0.46, 95% CI 0.22-0.97, p=0.04). After exclusion of patients with preoperative hearing class D, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83, p=0.016). Since tumor size was significantly larger in the therapy group, logistic regression analysis was additionally performed. The risk for hearing loss was adjusted four times lower in the therapy group compared to the control group (OR 0.25, 95% CI 0.09-0.65, p=0.003). Postoperative facial nerve functions were excellent in most patients of both groups. However, both ITT and logistic regression analysis (adjusted for tumor size) were not significant, but pointed to a potential beneficial effect in preventing deterioration of facial nerve function to HB IV-VI. Apart from dose-dependent hypotension (p<0,001), the study medication was well tolerated.

Conclusions: Prophylactic nimodipine is safe and should be recommended in VS surgery to preserve hearing. Prophylactic treatment with neuroprotective drugs prior to surgeries with nerve tissue at risk seems to be a novel and promising concept.