gms | German Medical Science

Objective: to correlate the risk of CSF Fistula with the extension of the petrous bone pneumatisation for the retrosigmoid approach and opening of the intern auditory canal.

Method: 140 patients submitted to resection of a vestibular schwannoma by a retrosigmoid approach were evaluated regarding the extension of the petrous bone pneumatisation and incidence of CSF Fistula. The evaluation was performed comparing the pneumatisation of the pre-operative thin sliced CT-scans with the opening of the air cells in the post-operative thin sliced CT-Scans and the clinical outcome.

Results: the CSF Fistula and its consequences for the clinical outcome and the length of the hospital stay in the vestibular schwannoma surgery represents a big issue for the surgeon and the patient. To achieve a complete resection of the tumor it is necessary to open the intern auditory canal during the surgery and consequently if the temporal bone is pneumatisated it represents a higher risk of a CSF-Fistula. Despite the obvious risk this issue was never studied in detail. We evaluated if the risk of a CSF-Fistula in patients in which the penumatisated intern auditory canal was opened during surgery correlates with the actual higher incidence of a CSF-Fistula. The incidence of CSF-Fistula was 12 %. From the patients with CSF-Fistula 80 % had a pneumatisated intern auditory canal witch was opened during surgery proving that the risk of CSF-Fistula is actually higher in patients in whom the intern auditory canal is pneumatisated.

Conclusions: the pre-operative evaluation of the pneumatisation of the temporal bone, specially the intern auditory canal, is essential for the surgeon to reduce the risk of a CSF-Fistula complication, thus the risk of a CSF-Fistula is 66 % higher when the petrous bone is pneumatisated.