A decompressive lumbar laminectomy is usually recommended only when specific conditions are met. In general, surgery is recommended when a spinal nerve root(s) is pinched and you have:
Leg pain which limits your normal daily activities
Weakness in your leg(s) or feet
Numbness in your legs
Difficulty in walking or standing
What is It?
Lumbar decompression is an operation performed on the lower spine to relieve pressure on one or more nerve roots. The procedure may involve a complete or partial laminectomy. The term is derived from lumbar (lower spine), lamina (part of the spinal canal’s bony roof), and -ectomy (removal).
Why is it Done?
Pressure on a nerve root in the lower spine, often called nerve root compression, causes back and leg pain. In this operation the surgeon reaches the lumbar spine through a small incision in the lower back. After the muscles of the spine are spread, a portion of the lamina is removed to expose the compressed nerve root(s).
Pressure is relieved by removal of the source of compression part of the herniated disc, thickened “wear and tear” tissue, a disc fragment, a tumor, or a rough protrusion of bone, called a bone spur.
What Happens Afterwards?
Successful recovery from lumbar laminectomy requires that you approach the operation and recovery period with confidence based on a thorough understanding of the process. Your surgeon has the training and expertise to correct physical defects by performing the operation; he and the rest of the health care team will support your recovery. Your body is able to heal the involved muscle, nerve, and bone tissues. Full recovery, however, will also depend on your having a strong, positive attitude, setting small goals for improvement, and working steadily to accomplish each goal.
Surgery for lumbar decompression is performed with the patient lying on his/her abdomen. A small incision is made in the lower back. The length of incision is kept as small as possible, but may vary according to the severity of the problem.
After a retractor is used to hold aside fat and muscle, the lamina is exposed. Part of it is cut away to uncover the ligamentum flavum – a ligament that supports the spinal column.
Entering the Spinal Canal
Next an opening is cut in the ligamentum flavum (tissue attached to adjacent bones) through which the spinal canal is reached. The compressed nerve is now seen, as is the cauda equina (bundle of nerve fibers) to which it is attached. The cause of compression may now also be identified – a bulging, ruptured or herniated disc, or perhaps a bone spur.
Sometimes a fragment of disc has moved away from the disc space to press on the nerve root as it leaves the spinal canal. This will often cause more severe symptoms.
Removal of the Herniated disc
The compressed nerve is gently retracted to one side, and the herniated disc is removed. As much of the disc is taken out as is necessary to take pressure off the nerve. Some surgeons will remove all “safely available” disc material. After the cause of compression is removed, the nerve can begin to heal. The space left after removal of the disc should gradually fill with connective tissue. In many cases, the disc does not need to be removed once the lamina and ligamentum flavum have been removed to free up the spinal canal..
The operation is completed when the incision is closed in several layers. The suture material used to close the skin can be pulled out from one end as a single piece. If the suture does not come out in one piece, the ends can be cut flush with the skin because it is absorbable and will completely reabsorb in a matter of weeks.
Lumbar Decompression Success rates
The success rate of surgery is favorable. Following surgery, approximately 70% to 80% of patients will have significant improvement in their function (ability to perform normal daily activities) and markedly reduced level of pain and discomfort.
Laminectomy risks and complications
The potential risks and complications with a laminectomy procedure include:
Nerve root damage (less than 1 in 100) or bowel/bladder incontinence (1 in 10,000). Paralysis would be extremely unusual since the spinal cord stops at about the T12 or L1 level, and surgery is usually done well below this level.
1 to 10% % of the time a cerebrospinal fluid leak may be encountered if the dural sac is breached. This does not change the outcome of the surgery, and generally a patient just needs to lie down for about 24 hours after surgery to allow the leak to seal. In most cases, the dural tear is repaired at the time of surgery and sealed with a special glue to prevent leakage.
Infections happen in about 1% of any elective cases, and although this is a major nuisance and often requires further surgery to clean it up along with IV antibiotics, it generally can be managed and cured effectively.
Bleeding is an uncommon complication as there are no major blood vessels in the area. However a heamatoma (blood clot) may form under the wound. If this occurs, further surgery to evacuate the haematoma may be required.
In approximately 5 to 10% of cases, postoperative instability of the operated level can be encountered. This complication can be minimised by avoiding the amount of bone resection during surgery. Also, the natural history of a degenerative facet joint may lead it to continue to degenerate on its own and result in a degenerative spondylolisthesis. Either of these conditions can be treated by fusing the affected joint at a later date.
General anaesthetic complications such as myocardial infarction (heart attack), blood clots, stroke, pneumonia or pulmonary embolism can happen with any surgery. Although in the general population these complications are rare, lumbar decompression surgery for spinal stenosis is generally done for elderly patients and therefore the risk of general anaesthetic complications is somewhat higher.
The results are much better for relief of leg pain caused by spinal stenosis, and not nearly as reliable for relief of lower back pain. Lumbar spinal stenosis is often created by the facet joints becoming arthritic, and much of the back pain is from the arthritis. Although removing the lamina and part of the facet joint can create more room for the nerve roots it does not eliminate the arthritis. Unfortunately, the symptoms may recur after several years as the degenerative process that originally produced the spinal stenosis continues.
In certain instances the success rate of a decompression for spinal stenosis can be enhanced by also fusing a joint. Fusing the joint prevents the spinal stenosis from recurring and can help eliminate pain from an unstable segment. Fusion surgery is especially useful if there is a degenerative spondylolisthesis associated with the stenosis. Generally speaking, if there is multi-level stenosis from a congenitally shallow canal a fusion is not necessary; however, if the stenosis is at one level from an unstable joint (e.g. degenerative spondylolisthesis), then a decompression surgery with a fusion is a more reliable procedure. Your surgeon will be able to decide on the best procedure for you and will be able to perform either procedure at the time of surgery.