1. Division of Neurosurgery, Department of Surgery, Radiology, Anaesthesia and Intensive Care, University Hospital of the West Indies, University of the West Indies, Mona, Kingston, Jamaica
2. Royal Preston Hospital, Lancashire Teaching Hospitals NHS Trust, Preston, UK
3. Department of Neurosurgery, Hirslanden Hospital, Zurich, Switzerland
4. Department of Neurosurgery, University Medicine Goettingen, Georg-August-University Goettingen, Goettingen, Germany