1 Division of Neurosurgery, Department of General Surgery, Khoo Teck Puat Hospital, Singapore City, Singapore; Essex Neuroscience Centre, Department of Neurosurgery, Queen's Hospital, Rom Valley Way, Romford, Essex, United Kingdom. Electronic address: drquah@gmail.com.
2 Essex Neuroscience Centre, Department of Neurosurgery, Queen's Hospital, Rom Valley Way, Romford, Essex, United Kingdom.