Lumbar discectomy is the surgical removal of herniated disc material that presses on a nerve root or the spinal cord. Before the disc material is removed, some of the bone from the affected vertebra may be removed using a laminotomy (a small hole created in the bone) or laminectomy (removal of some bone) to allow the surgeon to better see the area.
Lumbar discectomy traditionally required a large incision and tended to require a longer time to heal. However, nowadays with the use of precise imaging tools, it is possible to localise the disc prolapse very precisely and therefore the surgical approach can be kept minimal (ie minimally invasive surgery). By minimising the surgical procedure, there is less damage to muscle and bone thereby improving postoperative pain and rehabilitation. In fact most patients are discharged within 24 hours after a routine minimally invasive discectomy.
There are various techniques that may be used for a lumbar discectomy. One of the most popular techniques is using a microscope or magnifying loupes. We also sometimes use an endoscope (ie a camera inserted through a small skin incision) for cases that are suitable for this approach. These various techniques will be described in more detail in other sections of this website.
Lumbar discectomy can alleviate symptoms from a herniated disc in the low back. The main goal of discectomy surgery is to remove the part of the disc that is putting pressure on a spinal nerve root. Taking out the injured portion of the disc also reduces chances that the disc will herniate again.
Lumbar disc protrusions are not usually operated upon early, but there are some clear situations when we may recommend early surgery: –
-If there is evidence of severe weakness of the foot, ankle or leg, early surgery may be offered.
-If the pain in the leg is so severe that narcotic analgesia is not controlling the pain, early surgery may again be an option.
-Severe bilateral leg pain (ie pain running down both legs) with weakness or numbness.
-Finally, if there is a suggestion of problems with the nerves that supply the bladder or bowel, early surgery is advocated. In this latter situation, an inability to pass urine may be evident, or there may be numbness in the crotch area, buttocks or when passing urine. This situation usually necessitates emergent or early surgery.
The procedure can be performed as a day stay surgery, but most patients stay in hospital for 1-2 nights. General anaesthesia is utilised and the surgery is performed through a small incision.
Discectomy surgery is usually done with the patient kneeling face down in a special frame. In the majority of cases a small incision and endoscopic surgery is is performed, but sometimes the surgery cannot be performed through this approach ie obesity, difficulties during surgery etc, and therefore a more standard approach is used. Usually a small window is made on one side of a spinous process through the removal of some bone and ligament to allow visualization of the disc bulge and involved root.
Through gentle dissection under illumination and magnification, the interface between the nerve root and disc bulge is identified and the offending fragment is removed. Only a small portion of disc is removed. The whole disc is not removed, although any loose fragments felt through the hole in the annulus (outer shell of the disc) are removed. The tear in the annulus is not repaired. After the nerve is freed completely the operation is completed. Typically this takes 1-2 hours to perform.
Infection is an important risk and most be considered in all operations. The infection rate in our centres is below 2% and patients are usually given prophylactic antibiotics.
Dural Tear. Small tear to the lining of nerves.
Problems with anaesthesia include drug reaction and respiratory problems. The chance of a serious or permanent complication is less than one in a thousand. These issues are usually short term and can be discussed with the anaesthetist.
Thrombophlebitis (Blood Clots) can precipitate as clot in the veins of the thigh called DVT (deep venous thrombosis), clot in the lungs PE (pulmonary embolism. Usually pressure stockings to keep the blood in the legs moving are used post operatively and medications that thin the blood and prevent blood clots from forming are administered if this condition is suspected. Active movement is advised as soon as possible.
Injury to the nerve may occur in less than 1% of cases. This would cause weakness in the ankle, foot or knee depending on the nerve that was damaged. Although the risk of damage to bowel and blader nerves is extremely rare ie 1 in 10,000 cases, it has been reported in the literature.