A series of 12 patients with intraforaminal neurinomas in the lumbosacral space was reviewed. Our classification according to tumor extension relative to the affected root into intradural intra-arachnoid, intraforaminal extra-arachnoid, and extraforaminal types was useful in determining the best surgical approach to achieve root preservation and minimal postoperative deficits. Where sacrifice of roots was unavoidable, surprisingly few neurological deficits occurred.