Microdiscectomy is a surgical procedure for the relief of pain and other symptoms that occur when a herniated disc in the spine presses on an adjacent nerve root. During the operation, the surgeon frees the nerve by removing small fragments of disc, bone and ligament.

Microdiscectomy is sometimes described as a minimally invasive spine surgery, because it requires only a small incision and the use of a microscope or surgical glasses, called loupes, to magnify the site where the injury has occurred. The surgeon also uses smaller tools and instruments to work in the restricted space of the spine. Microdiscectomy is a type of spinal decompression surgery, and the term microdecompression – which describes the surgical removal of any bone or ligament that is compressing a nerve – may also be used to describe the procedure. However, the term "microdiscectomy" is more specific to the removal of the fragment of herniated disc tissue that is causing the patient’s symptoms.

Because most patients will recover from a herniated disc without surgery, microdiscectomy is recommended only after conservative treatment, including physical therapy, cortisone injections, and other medication have been tried for a period of at least 6 to 12 weeks, without bringing relief. In some cases, motor weakness may be a reason to have this surgery sooner. Patients with cauda equina syndrome require immediate surgical intervention. This is a condition in which pressure on the nerves in the lower portion of the spine affects bladder and bowel function, but it affects less than 1% of people.

Regardless of which particular microdiscectomy technique selected, the surgical goal is the same: to remove the disc fragment and any bone or ligament that may be compressing the nerve root. To do so, the surgeon creates a small window in the vertebra (a procedure also called a laminotomy) and pulls away the ligamentum flavum, the underlying tissue, to reveal the dura (the covering of the spine) and the nerve root. The herniated part of the disc is then removed to complete the nerve decompression.

Imaging techniques, including X-rays, are used before, and sometimes during, the surgery to ensure localization of the correct operative site.

While herniated discs may occur in almost any level of the spine, lumbar microdiscectomy – surgery in the lower portion of the back – is the most common site for this procedure.