[Small acoustic neuroma: observation or treatment? A review of 207 cases]

The management of small acoustic neuromas (AN) whether localized in an intracanalar position (stage I) or with a small extension of less then 2 cm into the cerebellopontine angle (stage II) remains under debate. Proposed strategies include surgery, stereotactic irradiation and observation. From 1987 to 1997, among 343 AN referred to our department, 207 were small (83 stage I and 124 stage II). Initially, 72 patients were treated conservatively mainly because of their age (over 60-65) and 132 were operated on. Three patients underwent irradiation because of their poor general condition. Significant tumor growth was observed in 15 cases in the conservative treatment group; 14 of these patients underwent secondary surgery and one irradiation. Among the 146 AN operated on (132 initially and 14 secondarily), 142 small AN were operated on via a transpetrosal approach (64% translabyrinthine, 21% middle-fossa and 15% retrosigmoid) and 4 AN, which became large tumors during the observation period, were treated through the translabyrinthine approach. No mortality was observed in our series. Postoperative complications included 11 CSF leakages necessitating reoperation (8%). In 93% of the cases, postoperative facial function at one year was good. Hearing preservation was attempted in 51 selected cases (pure tone average=50 dB, speech discrimination score 100%) with a 51% success rate (53% and 48% through middle-fossa and retrosigmoid approaches respectively). In our opinion, surgery with this risk-benefit ratio is indicated for small AN, except in the elderly for whom conservative management is preferred and in patients in poor clinical condition with a growing AN, for whom irradiation is recommended.