1Department of Neurological Surgery, School of Medicine, University of California, San Francisco (M.S.B.E., M.S.B.)
2Doctors Hospital, Modesto (W.G.B.), California
3Section of Neurosurgery, Ft. Miley Veterans Administration Hospital, San Francisco (M.S.B.E.)
4Section of Neurosurgery, Ft. Miley Veterans Administration Hospital, San Francisco; California