1 Department of Surgery (Division of Neurosurgery), QEII Health Sciences Centre and Dalhousie University, 3844-1796 Summer Street, Halifax, NS, B3H 3A7, Canada.
2 Department of Surgery (Division of Neurosurgery), IWK Health Centre and Dalhousie University, Halifax, NS, Canada.
3 Department of Surgery (Division of Neurosurgery), QEII Health Sciences Centre and Dalhousie University, 3844-1796 Summer Street, Halifax, NS, B3H 3A7, Canada. weise@dal.ca.