Kanchan Kumar Mukherjee1, Manjul Tripathi2. 1. Department of Neurosurgery Neurosurgery Office Nehru Hospital, 5th Floor, Post Graduate Institute of Medical Education & Research, Chandigarh, India, 160012. kk_mukherjee@hotmail.com. 2. Department of Neurosurgery Neurosurgery Office Nehru Hospital, 5th Floor, Post Graduate Institute of Medical Education & Research, Chandigarh, India, 160012.