Current management of acoustic neuromas: review of surgical approaches and outcomes

Abstract

The management options for patients with acoustic neuromas is discussed with a review of 164 patients assessed and treated between 1994 and 1998. Twenty-one patients have neurofibromatosis type II. In 33 cases initial observation was undertaken with repeated imaging. Surgical removal of 122 tumours was performed in 121 patients. Eleven of these patients have NF2, of whom three underwent Auditory Brainstem Implantation. Hearing preservation tumour removal was attempted in 37 and was successful in 20 (54%). The middle cranial fossa approach was used in ten cases with 100% successful hearing preservation. The retrosigmoid approach was used in 27 cases with 36% successful hearing preservation. Non-hearing preservation tumour removal was performed in 85 cases where hearing was poor or the tumour measured more than 2 cm within the cerebellopontine angle. The translabyrinthine approach was used in 80 of these patients. Postoperative facial nerve outcome was dependent on tumour size. All 38 patients with tumours </= 1.5 cm have normal (Grade 1) facial function. For all sized tumours, 90% of patients have good facial function (82% Grade 1, 8% Grade 2), 7% of patients have moderate function (6% Grade 3 and 1% Grade 4) and only 3% of patients have poor function (2% Grade 5, 1% Grade 6). Lasting complications were minimal with no operative mortality and eight patients (6.4%) suffering CSF fistulae. Seven patients in this series have had stereotactic radiation with variable outcome. The radiobiology of both single dose and fractionated stereotactic radiation is described and the current role of stereotactic radiation in the management of acoustic neuromas is discussed. Surgical tumour removal by an experienced multi-disciplinary team remains the primary treatment modality for acoustic neuromas. The middle cranial fossa approach is recommended for management of intracanalicular tumours. The translabyrinthine approach facilitates facial nerve preservation, particularly in patients with large tumours.