Reduction of cerebrospinal fluid rhinorrhea after vestibular schwannoma surgery by reconstruction of the drilled porus acusticus with hydroxyapatite bone cement

Object. Cerebrospinal fluid (CSF) rhinorrhea remains a significant cause of morbidity after resection of vestibular schwannomas (VSs), with rates of rhinorrhea after this procedure reported to range between 0 and 27%. The authors investigated whether reconstruction of the drilled posterior wall of the porus acusticus with hydroxyapatite cement (HAC) would decrease the incidence of postoperative CSF rhinorrhea. Methods. A prospective observational study of 130 consecutive patients who underwent surgery for reconstruction of the posterior wall of the drilled porus acusticus with HAC was conducted between October 2002 and September 2005. All patients underwent a retrosigmoid transmeatal approach for VS resection and were followed up to document cases of CSF rhinorrhea, incisional CSF leak, meningitis, or rhinorrhea-associated meningitis. A cohort of 150 patients with VSs who were treated with the same surgical approach but without HAC reconstruction served as a control group. Results. The authors found that HAC reconstruction of the porus acusticus wall significantly reduced the rate of postoperative CSF rhinorrhea in their patients. In the patients treated with HAC, rhinorrhea developed in only three patients (2.3%) compared with 18 patients (12%) in the control group. This was a statistically significant finding (p = 0.002, odds ratio = 5.8). Conclusions. The use of HAC in the reconstruction of the drilled posterior wall of the porus acusticus, occluding exposed air cells, greatly reduces the risk of CSF rhinorrhea.