Ventral foramen magnum meningiomas

Abstract
Object. Ventral foramen magnum meningiomas (VFMMs) are rare lesions that account for more than 3% of all meningiomas. These are among the most challenging of all meningiomas to treat. The authors comprehensively analyzed multiple features in a series of VFMMs. Methods. A retrospective study was performed of 18 patients who harbored a meningioma in the ventral foramen magnum (mean follow-up period, 40 months) and underwent surgery via a transcondylar approach. Sixteen patients underwent surgery for the first time: 12 underwent gross-total (75%), two near-total (12.5%), and two subtotal (12.5%) tumor removal. The remaining two patients were treated for a recurrent tumor. After obtaining postoperative Karnofsky Performance Scale (KPS) scores at follow up, statistically significant improvement was demonstrated compared with the preoperative scores. The extent of surgery and higher preoperative KPS scores were variables that showed statistically significant favorable influence on outcome. Ninth and 10th crania...