J Korean Neurosurg Soc.  2001 Nov;30(11):1308-1313.

Gamma-Knife Radiosurgery for Vestibular Schwannoma

• Paeng SH
• Kim MS
• Sim HB
• Jeong YG
• Lee SI
• Jung YT
• Kim SC
• Sim JH

Abstract

OBJECT: The goals of radiosurgery include preservation of neurological function and prevention of tumor growth. We document the results of gamma-knife radio-surgery for vestibular schwannoma. METHOD AND OBJECT: Eighty-two patients underwent stereotactic radiosurgery for an vestibular schwannoma from October, 1994 to December, 2000. Sixty-five of these patients were followed up for radiological and clinical evaluation. As pregamma-knife modality, surgical resection were done in 23 patients,and V-P shunt in 2 patients. Initial symptoms were headache(n=45), dizziness(n=16), tinnitus(n=17). While normal facial function(House-Brackmann grade 1) was present in 48 patients(73.8%), other patients showed grade 2 function in 8, grade 3 function in 7,and grade 4 function in 2. The Gardner/Robertson scale was used to code hearing function. Male to female ratio was 1:3. Mean tumor volume was 7.98cm3. Mean dose delivered to the tumor margin was 14.2Gy,and mean maximal dose was 28.3Gy.
RESULTS
Mean follow-up duration of 19.9 months. Thirty-five showed decrease(53.8%) in size, 19 patients(29.2%) stationary, 3(4.6%) initial decrease follow up increase, 5(7.6%) initial increase follow up decrease,and 59 patients (90.8%) were well controlled. Two patients experienced transient facial neuropathy, one transient trigeminal neuropathy, and one transient hearing deterioration. After gamma-knife radiosurgery, ventriculoperitoneal shunt was done in 4 patients.
CONCLUSIONS
Gamma-knife radiosurgery can be used to treat postoperative residual tumors as well as in patients with concomitant medical problems in patients with preserved hearing function. Gamma-knife radiosurgery is safe and effective method to treat small, medium sized(less than 3cm in extracanalicular diameter), intracanalicular vestibular schwannoma, associated with low rate of cranial neuropathy.

Keyword

Vestibular schwannoma; Radiosurgery; Gamma knife surgery; Hearing function; Facial function

MeSH Terms

Cranial Nerve Diseases
Facial Nerve Diseases
Female
Follow-Up Studies
Hearing
Humans
Male
Neoplasm, Residual
Neuroma, Acoustic*
Radiosurgery*
Trigeminal Nerve Diseases
Tumor Burden
Ventriculoperitoneal Shunt