Title:
Hearing outcome after gamma knife radiosurgery for vestibular schwannoma: a prospective Belgian clinical study
Authors:
C . Delbrouck 1,4S. Hassid ,. Choufani O.,De Witte D. D,vriendt 3,and N. Massager 2,4 1 2 3
Institutions:
ENT departmen4, Neurosurgery department, Erasmus University Hospital, Radiation therapy department, Institut J. Bordet and Gamma Knife Center, Université Libre de Bruxelles, Brussels, Belgium
Keywords:
Vestibular schwannoma; gamma knife, radiosurgery, hearing preservation
Pages:
77 - 84
Abstract:
Hearing outcome after gamma knife radiosurgery for vestibular schwannoma: a prospective Belgian clinical study. Introduction: Leksel Gamma Knife (LGK) radiosurgery is a safe and efficient therapeutic approach for vestibular schwannoma (VS) with low side effects. The goal of radiosurgery is not necessarily to cause significant tumour necro- sis or to obtain a complete radiographic response, but to halt the tumours growth permanently through its biological elimination. The 2 major aims of radiosurgery for VS are long-term tumour control and functional hearing preservation. The purpose of this study is to report our experience with LGK radiosurgery in the management of VS and to evaluate the hearing preservation rate after a minimum one-year follow-up. Material and methods: Between January 2000 and January 2011, 415 patients with unilateralVS underwent LGK radio- surgery at the University Erasmus Hospital of Brussels. There were 349 patients with previously untreatedVS (86 grade I, 96 grade II, 141 grade III, 9 grade IVa, 17 unknown grades, according to Koos) and 66 patients with post-operative residual tumour. All patients in our series underwent evaluation with high resolution neurodiagnostic imaging including computed tomography and magnetic resonance imaging, and clinical evaluation as well as audiological tests that includ- ed tonal and speech audiometries. The Gardner Robertson (GR) classification is used to report the results of this study. We identified 276 patients treated for VS with LGK, tested and retested with speech and tonal audiometries by the same team, and followed for a minimum of one year. Results: Before LGK, 144 patients had serviceable (85 GR class I and 59 GR class II) hearing; 95 (65.97%) of these patients had preservation of serviceable hearing (Pure tone average 50 db and Speech discrimination 50%) at mini- mum one-year audiological follow-up. It was observed that 44 of the 85 GR class I patients (51.76%) maintained their level of audition and 66 of these (74.64%) preserved serviceable hearing. In the 34 patients with preradiosurgery non- serviceable hearing (GR class III-IV) 25 of these patients (73.52%) maintained their hearing. The tumour was stable or declining in size in 90.44% of cases. Conclusion: LGK radiosurgery provides excellent tumour control in vestibular schwannomas and has low toxicity even after long-term follow-up.
Issue:
Suppl. 17, 2011


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Hearing outcome after gamma knife radiosurgery for vestibular schwannoma: a prospective Belgian clinical study