Facial nerve preservation after vestibular schwannoma Gamma Knife radiosurgery

• Published in: Journal of neuro-oncology 2009-05, Vol.93 (1), p.41-48
• Main Authors: Yang, Isaac, Sughrue, Michael E., Han, Seunggu J., Fang, Shanna, Aranda, Derick, Cheung, Steven W., Pitts, Lawrence H., Parsa, Andrew T.
• Format: Article
• Language: English
• Subjects: Age Factors; Facial Nerve - radiation effects; Facial Nerve - surgery; Facial Nerve Injuries - epidemiology; Facial Nerve Injuries - etiology; Humans; Medicine; Medicine & Public Health; Middle Aged; Neurology; Neuroma, Acoustic - pathology; Neuroma, Acoustic - surgery; Oncology; Postoperative Complications - epidemiology; Postoperative Complications - etiology; Radiosurgery - adverse effects; Radiosurgery - methods; Radiotherapy Dosage; Topic Review
• ISSN: 0167-594X; 1573-7373
• DOI: 10.1007/s11060-009-9842-3

Objective Facial nerve preservation is a critical measure of clinical outcome after vestibular schwannoma treatment. Gamma Knife radiosurgery has evolved into a practical treatment modality for vestibular schwannoma patients, with several reported series from a variety of centers. In this study, we report the results of an objective analysis of reported facial nerve outcomes after the treatment of vestibular schwannomas with Gamma Knife radiosurgery. Materials and methods A Boolean Pub Med search of the English language literature revealed a total of 23 published studies reporting assessable and quantifiable outcome data regarding facial nerve function in 2,204 patients who were treated with Gamma Knife radiosurgery for vestibular schwannoma. Inclusion criteria for articles were: (1) Facial nerve preservation rates were reported specifically for vestibular schwannoma, (2) Facial nerve functional outcome was reported using the House–Brackmann classification (HBC) for facial nerve function, (3) Tumor size was documented, and (4) Gamma Knife radiosurgery was the only radiosurgical modality used in the report. The data were then aggregated and analyzed based on radiation doses delivered, tumor volume, and patient age. Results An overall facial nerve preservation rate of 96.2% was found after Gamma Knife radiosurgery for vestibular schwannoma in our analysis. Patients receiving less than or equal to 13 Gy of radiation at the marginal dose had a better facial nerve preservation rate than those who received higher doses (≤13 Gy = 98.5% vs. >13 Gy = 94.7%, P  1.5 cm 3 95.5%, P