OUTCOMES AFTER TREATMENT OF VESTIBULAR SCHWANNOMA BY 2 DIFFERENT MODALITIES; MICROSURGICAL AND RADIOSURGICAL TECHNIQUES

Abstract

Background The choice between microsurgery and radiosurgery for treatment of vestibular schwannoma (VS) is debatable. There are a lot of treatment schedules, but the widely accepted is to treat tumors larger than 2.5 cm surgically, while tumors less than 2.5 cm could be offered the radiosurgical treatment. The aim of this work was to assess efficacy and safety of surgery and radiosurgery in treatment of vestibular schwannoma.
Methods The study was performed as a retrospective evaluation of 70 patients who had undergone vestibular schwannoma treatment during the period between June 2004 and June 2010. Patients with follow up less than one year and those subjected to previous vestibular schwannoma treatment were excluded from the study. The patients were classified into two groups; surgery group included 20 patients and radiosurgery groups included 50 patients. Patient records, treatment reports, and follow-up data were analyzed. The main outcome measures were magnetic resonance imaging, neurological status, patient complaints, and complications.
Results In the surgery group total or near total tumor removal was achieved in 85% of patients and tumor recurrence after surgery occurred in 1 patient (5%) (tumor control rate was 95%). Preservation of useful hearing was achieved in 30.8% of patients. Facial nerve was anatomically preserved in 85% of patients, and functional preservation (House – Brackmann grade I or II) was achieved in 75% of patients at the last follow up after surgery. Class T3b tumors showed the best results, with hearing preservation rate of 75% and functional facial nerve preservation rate of 83.3%. In the radiosurgery group tumor control rate was 98%. Hearing preservation rate was 57.1%, however facial nerve preservation rate was 98%. Results of Class T3b tumors were 50% and 80% for hearing and facial nerve preservation rate respectively.
Conclusions Tumor control rate after total or near total removal of vestibular schwannoma was comparable to control rate after radiosurgery. Although hearing and facial nerve preservation were better in the radiosurgery group, the results of Class T3b tumors after surgery were comparable to those after radiosurgery.
Keywords Acoustic neuroma; Cerebellopontine angle; Gamma knife; Radiosurgery; Vestibular schwannoma