Cerebrospinal fluid leak after acoustic neuroma surgery: influence of tumor size and surgical approach on incidence and response to treatment

Object. The aims of this study were to review the incidence of cerebrospinal fluid (CSF) leakage complicating the removal of acoustic neuroma and to identify factors that influence its occurrence and treatment. Methods. Prospective information on consecutive patients who underwent operation for acoustic neuroma was supplemented by a retrospective review of the medical records in which patients with CSF leaks complicating tumor removal were identified. This paper represents a continuation of a previously published series and thus compiles the authors' continuous experience over the last 24 years of practice. In 624 cases of acoustic neuroma the authors observed an overall incidence of 10.7% for CSF leak. The rate of leakage was significantly lower in the last 9 years compared with the first 15, most likely because of the abandonment of the combined translabyrinthine (TL)-middle fossa exposure. There was no difference in the leakage rate between TL and retrosigmoid (RS) approaches, although there were differences: in the site of the leak (wound leaks occurred more frequently after a TL and otorrhea after an RS approach, respectively). Tumor size (maximum extracanalicular diameter) had a significant effect on the leakage rate overall and for RS but not for TL procedures. The majority of leaks ceased with nonsurgical treatments: (18% with expectant management and 49% with lumbar CSF drainage). However, TL leaks (especially rhinorrhea) required surgical repair significantly more often than RS leaks. This has not been reported previously. Conclusions. The rate of CSF leakage after TL and RS procedures has remained stable. Factors influencing its occurrence include tumor size but not surgical approach. The TL-related leaks had a significantly higher surgical repair rate than RS-related leaks, an additional factor to consider when choosing an approach. The problem of CSF leakage becomes increasingly important as nonsurgical treatments for acoustic neuroma are developed.