Minimal invasive micro discectomy is performed for patients with disc herniation that have exhausted non-operative treatment. With micro discectomy, only the protruding disc material is removed, not the whole disc. This is performed through a small incision in the lower back. The muscles are elevated and retracted off the bony arch and roof of the spine (lamina) to gain access to the spine. The spinal canal is entered by removing a membrane in between the lamina and over the nerve roots (ligamentum flavum). Often, a small portion of the inside facet joint is removed, both to enable access to the nerve root and to remove pressure on the nerve. Under microscope magnification, the nerve root is then gently moved to the side and the disc material is removed from under the nerve root. The disc is then entered to remove any further loose disc fragment within it.Good relief from sciatica leg symptoms following micro discectomy surgery usually occurs in approximately 70 – 80% of cases. The results of the operation are however not nearly as reliable for the relief of lower back pain. Much of the back pain experienced comes from the damaged disc and associated muscular spasms, therefore, discectomy surgery cannot eliminate this and it should not be regarded as the main aim of the surgery.