hemi = half
laminectomy = removal of all or part of the lamina, with the lamina being the back part of your vertebrae
So a hemilaminectomy is a surgery where the lamina is removed on the left or right side of the back of a vertebrae. This surgery is done to give more room for the spinal canal in the case of stenosis or to give the surgeon access to the spinal or foraminal areas to do a discectomy or foraminectomy.
HTH!
