Accurate localisation by MRI scan and microscopic technique have made it possible to approach disc fragments through small incisions with minimal disturbance to the underlying soft tissues. In the patient of average build, the incision is about an inch long. The muscle beneath is retracted to one side exposing a natural gap between the vertebrae (the interlaminar space). This is covered by an elastic fibrous sheet called the ligamentum flavum. Using a microscope the surgeon cuts a window in this sheet to enter the spinal canal. The nerve root is usually clearly visible and is gently moved out of the way. The annular ring of the disc is then cut, and the offending disc fragment can be removed with fine instruments called rongeurs. Afterwards, time is taken to probe and irrigate the disc space to make sure there are no residual fragments.
The disc removal is partial. To remove it entirely would entail much more extensive surgery with the risk of damaging a large blood vessel in the abdomen, and a likely need for fusion. Partial excision is usually all that is necessary for a lasting cure, but leaves a 5% chance of reherniation in the future.
Closure of the wound is achieved by placing absorbable stitches in the outer membrane of the muscle (fascia) and deeper layer of the skin. The outer skin itself is closed with steristrips which are removed after about a week.