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Radiosurgery for acoustic neuromas: results of low-dose treatment
Yoshiyasu Iwai1, Kazuhiro Yamanaka, Masato Shiotani
1Department of Neurosurgery, Osaka City General Hospital, Osaka, Japan. y-iwai@rc5.so-net.ne.jp
Objective:
The results of radiosurgical treatment of acoustic neuromas have improved by reducing the tumor marginal doses. We report relatively long-term follow-up results (>5 yr) for patients who underwent low-dose radiosurgery.
Methods:
We treated and followed 51 consecutive patients with unilateral acoustic neuromas who were treated from January 1994 to December 1996 by gamma knife radiosurgery at low doses (
Results:
Clinical tumor growth control (without tumor resection) was achieved in 96% of patients, and the 5-year tumor growth control rate was 92%. Hearing was preserved in 59% of those with preradiosurgical hearing preservation (Gardner-Robertson Classes 1-4), and improvements (>20 dB of improvement) were noted in 9% of the patients with any hearing. Hearing was preserved at a useful level (Gardner-Robertson Classes 1 and 2) in 56% of patients. Although preexisting trigeminal neuropathy worsened in 4% of the patients, our patients did not experience new facial palsies or trigeminal neuropathies after radiosurgery. Facial spasm occurred in 6% of the patients, and intratumoral bleeding occurred in 4% of patients.
Conclusion:
Low-dose radiosurgery (
