gms | German Medical Science

Objective: In large tumors of the cerebello-pontine angle the preservation of the facial nerve function remains to be a challenge. We report about a group of 71 consecutive patients with special focus on this topic describing our operative strategies and tools we used during the procedure.

Methods: Records of the patients who were operated because of cerebello-pontine angle tumors between 1996 and 2016 with tumors larger than 2.5 cm in diameter were retrospectively analyzed. Follow up reached from 2 months to 225 months.

Results: 133 patients were operated between 1996 and 2016 because of cerebello-pontine angle tumors. 71 patients had tumors larger than 2.5 cm. in diameter. 41 of them had schwannomas (57.7%), 20 patients had meningiomas (28.2%), 10 patients (14.1%) had other histologies including carcinoma metastasis, cholesteatoma, epidermoid cysts, malignant melanoma and lymphomas. Most common symptoms were coordination and ataxia of varying degree (78.9%); followed closely by hearing loss and tinnitus (77.5%), nonetheless 16 patients had facial nerve dysfunction prior to surgery (22.5%), 4 of them with House – Brackmann grade IV and V (4.6%). 5 patients needed placement of an external ventricular drain prior to tumor removal (7%). Median tumor-size was 3.3 cm. Retrosigmoid approach was used. 72.5% of the patients were operated in semi-sitting position, 14.5% in prone position and 8.7% in lateral position. No operation had to be interrupted due to an air embolism. Complications included intracranial hemorrhages needing a surgical removal (2.8%), ventriculo-peritoneal shunt dependency (4.2%) and impaired wound healing needing a revision (5.6%).There was no fatal case. Median postoperative hospital stay was 11 days. 17 patients were lost to follow up after discharge; the median follow up with 54 patients was 51 months, of these 1 (1.9%) had House – Brackmann grade VI, and 6 (11.1%) had House – Brackmann grade IV and V facial nerve dysfunction. The tumor size and the preoperative facial nerve function were variables that affected the facial nerve outcome. Operations were performed with microsurgical facial nerve stimulation tools and continuous recording of evoked potentials. Recurrent tumor growth needing another surgical removal was noted in 4 patients (3 months to 9.3 years after surgery).

Conclusion: In large tumors of the cerebello-pontine angle the likelihood of complete loss of facial nerve function in long term after operation was only 1.4%, good facial nerve function defined as House – Brackmann grade I-III was 87%. Facial nerve stimulation is a most practicable tool in this setting and air embolism in semi-sitting was not a problem in our group of patients.