Exclusive surgical treatment for vestibular schwannoma regrowth or recurrence: A meta-analysis of the literature

Vestibular schwannomas can be treated in different ways, but for symptomatic or growing tumors, the gold standard is surgical removal of the lesion. In order to preserve neurovascular structures, partial removal is often performed, leaving a residual that may grow in subsequent years. To date, there is no consensus with regard to surgical treatment of vestibular schwannoma residuals, and so this review focuses on this topic. A structured search was performed on PubMed searching for all articles discussing vestibular schwannoma residuals and recurrences. Only articles discussing surgical treatment were included, focusing on studies which also examined facial nerve outcomes. A total of 51 articles were eligible for review and these included 375 patients. Statistical analysis was performed by correlating the following parameters: patients' gender and age at first surgery, surgical approach adopted at first and subsequent surgeries, tumor and residual size, and extent of resection (gross total, near total, subtotal or others) at first and subsequent surgical procedures. Facial nerve function was also analyzed focusing on its performance when correlated with the different surgical approaches. The data were analyzed by linear regression but there were no correlations between any of the parameters chosen. There was a statistically significant difference between the first approach used (mainly the retrosigmoid route) compared with subsequent approaches (mainly the translabyrinthine route). In total, 8.5 % of patients needed further treatment due to residual regrowth. Facial nerve outcome was independent of the parameters chosen. Exclusive surgical treatment for vestibular schwannoma residuals had a very low failure rate in terms of requiring further treatment. The approach usually chosen for second surgery was the translabyrinthine technique, and this may be explained by the location of the residual, rather than its size. The choice of a particular surgical approach rather than another had no influence on facial nerve function. Complications rates are comparable to Gamma Knife Radiosurgery's as reported in the literature.