[1] New York Med Coll, Dept Neurol Surg, Valhalla, NY 10595 USA
[2] New York Med Coll, Dept Otolaryngol Head & Neck Surg, Valhalla, NY 10595 USA
[3] New York Med Coll, Dept Cell Biol & Anat Sci, Valhalla, NY 10595 USA
[4] Univ So Calif, Dept Neurol Surg, Los Angeles, CA 90089 USA