Lumbar laminectomy (Open decompression)

By: Peter F. Ullrich, Jr., MD
December 18, 2003

Similar to a microdecompression, a lumbar laminectomy (open decompression) is a surgical procedure that is performed to alleviate pain caused by neural impingement. The laminectomy surgery is designed to remove a small portion of the bone over the nerve root and/or disc material from under the nerve root to give the nerve root more space and a better healing environment (see Figure 1).

A laminectomy is effective to decrease pain and improve function for patients with lumbar spinal stenosis. Spinal stenosis is a condition that primarily afflicts elderly patients, and is caused by degenerative changes that result in enlargement of the facet joints. The enlarged joints then place pressure on the nerves, and this pressure may be effectively relieved with a lumbar laminectomy.

Laminectomy surgical procedure

The lumbar laminectomy (open decompression) differs from a microdiscectomy in that the incision is longer and there is more muscle stripping.

• First, the back is approached through a two-inch to five-inch long incision in the midline of the back and the left and right back muscles (erector spinae) are dissected off the lamina on both sides and at multiple levels (see Figure 2).

• After the spine is approached, the lamina is removed (laminectomy) which allows visualization of the nerve roots.

• The facet joints, which are directly over the nerve roots, may then be undercut (trimmed) to give the nerve roots more room.

Post-operatively, patients are in the hospital for one to three days, and the individual patient's mobilization (return to normal activity) is largely dependent on his/her pre-operative condition and age. Directly following the procedure, patients are encouraged to walk. However, it is recommended that patients avoid excessive bending, lifting or twisting for six weeks in order to avoid pulling on the suture line before it heals.

Laminectomy success rate

The success rate of a laminectomy 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.

The laminectomy surgical 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.

Laminectomy risks and complications

The potential risks and complications with a laminectomy procedure include:

• Nerve root damage (1 in 1,000) 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 3% 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 to allow the leak to seal.

• 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.

• In approximately 5 to 10% of cases, postoperative instability of the operated level can be encountered. This complication can be minimized by avoiding the pars interarticularis during surgery, as this is an important structure for stability at a level. Weakening or cutting this bony structure can lead to an isthmic spondylolisthesis after 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 anesthetic 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, laminectomy surgery for spinal stenosis is generally done for elderly patients and therefore the risk of general anesthetic complications is somewhat higher.