gms | German Medical Science

Objective: Although the early diagnosis of acoustic neuromas (AN) gives opportunity to operate them at smaller size, Neurofibromatosis type 2 (NF2)-patients still have frequently large tumors due to rapid polytope growth and the need for keeping the remaining hearing in the last ear. Individual decisions are necesseary for timing of surgery, approach, extent of tumor removal and use of Auditory Brainstem Implant.

Method: Large tumors were defined as diameter of 3cm or more. Out of 131 surgeries with ABI there were 41 NF2-Patients with tumors of 3cm up to 6cm size.

Results: We used the translabyrinthian (TL, 22 patients) or the lateral suboccipital approach (SO, 19 patients).TL was mandatory when there was invasion of cochlea, vestibulum or middle ear by the AN. Patients with origin of polytope large tumors involving other cranial nerves than VIII and VII were operated SO either in the supine or semisitting position. A complete removal of large tumors should be achieved for oncological reasons, to prevent early recurrence and the limited value of irradiation and was possible in 39 of 41 patients. The remaining quality of life due to other cranial and peripheral nerve tumors, especially spinal or optic nerve tumors, has to be respected. ABI insertion was possible in 38 of 41 patients, all of them having some restoration of hearing by the device. The risk of surgery was given by size and infiltrative character of the tumor and not by the additional ABI procedure. We lost 2 patients due to pulmonary embolism. The facial nerve could not be preserved in 3 patients, prolonged recovery of the caudal cranial nerves occurred in 2 patients. 1 patient had prolonged wound healing following multiple previous surgeries.

Conclusions: The surgical risk of NF2-patients with large AN is elevated and the results concerning preservation of cranial nerve functions and hearing restoration are worse and less constant than in patients with small or no tumors. However, surgery is often the last option after previous incomplete removal or radiation therapy. Patients with Wishart type of NF2 and fast simultaneous growing tumors in different regions have the highest risk.