Radiosurgery of vestibular schwannomas: summary of experience in 829 cases.
OBJECTIVE
Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience.


METHODS
Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10-20 Gy). No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed).


CONCLUSIONS
Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.
Lunsford
L Dade
LD
Department of Neurological Surgery and Radiation Oncology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. lunsfordld@upmc.edu
Niranjan
Ajay
A
Flickinger
John C
JC
Maitz
Ann
A
Kondziolka
Douglas
D
D005260:Female; D005500:Follow-Up Studies; D006311:Hearing Disorders / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009367:Neoplasm Staging; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology / Q000601:surgery*; D011829:Radiation Dosage; D016634:Radiosurgery / Q000295:instrumentation*; D012720:Severity of Illness Index; D014277:Trigeminal Neuralgia / Q000209:etiology; D047368:Tumor Burden / Q000528:radiation effects