title: Prognostic factors of hearing preservation after gamma knife radiosurgery for vestibular schwannoma.
abstract: We conducted a prospective study to identify prognostic factors of hearing preservation after gamma knife radiosurgery (GKRS) for vestibular schwannoma (VS). Twenty-seven patients with unilateral VS and serviceable hearing underwent GKRS. The mean lesion diameter was 17.3mm (range 6.1-30.0mm), the median marginal dose was 12 Gy (11-15 Gy), and the mean follow-up duration was 35.7 months (9-81 months). The probabilities of hearing preservation after GKRS were calculated using the Kaplan-Meier method. Tumor growth was controlled in 26 of the 27 patients (96.3%), and rates of hearing preservation were 85.1% and 68.1% at 2 and 3 years, respectively. A normal auditory brainstem response (ABR) (p = 0.008) and Gardner-Robertson class I hearing (p = 0.012) before GKRS were found to be significant prognostic factors of a favorable outcome. Our findings suggest that a normal pre GKRS ABR strongly predicts hearing preservation after GKRS. Accordingly, we advise that ABR should be considered with other prognostic factors when GKRS is considered in patients with VS.
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Gangnam-gu, Seoul, Korea.
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Kim
authors.forename: Kyu Whan
authors.initials: KW
authors.lastname: Chung
authors.forename: Doo-Sik
authors.initials: DS
authors.lastname: Kong
authors.forename: Do-Hyun
authors.initials: DH
authors.lastname: Nam
authors.forename: Kwan
authors.initials: K
authors.lastname: Park
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Sung Hwa
authors.initials: SH
authors.lastname: Hong
authors.forename: Yang-Sun
authors.initials: YS
authors.lastname: Cho
authors.forename: Won-Ho
authors.initials: WH
authors.lastname: Chung
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D003056:Cochlear Nerve / Q000473:pathology / Q000528:radiation effects / Q000601:surgery; D003390:Cranial Nerve Neoplasms / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D011183:Postoperative Complications / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011379:Prognosis; D011446:Prospective Studies; D011829:Radiation Dosage; D011859:Radiography; D016634:Radiosurgery / Q000009:adverse effects* / Q000706:statistics & numerical data; D014725:Vestibular Nerve / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000160:Vestibulocochlear Nerve Diseases / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D055815:Young Adult