Although spine surgery has become much more reliable in the last 20 years or so, some patients will still have leg pain after a lumbar decompression surgery for spinal stenosis or a disc herniation.

See Lumbar (Low Back) Stenosis Surgery

Pain from a spinal stenosis may be resolved with decompression surgery. Lumbar Decompression Back Surgery

Watch Lumbar Herniated Disc Video

See Lumbar Spinal Stenosis

Sometimes this is a temporary condition as the nerve root or roots take time to heal. This can take days to weeks. If the pain is still there after 3 months, it is unlikely to improve on its own.

Below are a few reason why leg pain may persist after surgery.

Incorrect diagnosis

The #1 cause of postoperative leg pain is that the preoperative diagnosis was incorrect. This has become less likely as our preoperative imaging methods (e.g. MRI scans) have improved. But that being said, diagnosing the source of a patient's pain remains and inexact science.

See Getting an Accurate Back Pain Diagnosis


Dual problems causing pain

It is also possible that two different lesions are causing pain. For example, someone may have a herniated disc at the L4-L5 level with an L5 radiculopathy causing piriformis syndrome.

See Lumbar Radiculopathy

Watch Piriformis Syndrome Video

Decompressing the nerve may help resolve some of the patient’s pain, but the piriformis muscle also needs rehabilitation (which is often difficult).

Foraminal and central stenosis

Another common scenario is a patient who has both foraminal stenosis (narrowing of the disc space) and central stenosis. The central stenosis can be relieved with a decompression, but the decompression may not suffice for the foraminal stenosis. In these cases, a lumbar fusion may be necessary to address the foraminal stenosis.

Secondary disc herniation

After a microdiscectomy for a disc herniation, another disc may rupture and impinge again on the nerve root. This can happen anywhere from days to years after the surgery. The hallmark of this is pain that is gone initially after surgery, but then spontaneously returns. Postoperative inflammation of the nerve root can mimic a recurrent disc--with a return of pain 2-7 days after surgery--but will usually subside with time and rehabilitation.

See Microdiscectomy (Microdecompression) Spine Surgery


Nerve damage during surgery

A much less common cause of leg pain after surgery is nerve damage at the time of surgery. Nerve roots are generally tough and difficult to damage with a common surgical procedure.

Scar tissue

A really rare cause of postoperative leg pain, if it ever happens, is scar tissue. Scar tissue forms after all surgeries and it does not damage surrounding tissues. It can limit the mobility of a nerve root, but physical therapy can usually help in the early postoperative period.

See Scar Tissue and Pain After Back Surgery

Scar tissue only grows for 6-12 weeks and then gets softer with time. It is more commonly diagnosed as a cause of pain when there is no other obvious cause of postoperative pain, but the reality is that the patient’s pain is unlikely to be coming from scar tissue.

See Rehabilitation and Exercise Following Spine Surgery

For patients who have continued leg pain after spinal decompression surgery, alternative causes of the pain should be sought. It is often a frustrating situation, but patience and continued effort will often help alleviate the pain.

Learn more:

Treatment Options for Pain After Back Surgery

How Decompression Surgery Is Performed

Dr. Peter Ullrich is an orthopedic surgeon who retired from practice with more than 20 years of experience specializing in spine surgery. Dr. Ullrich previously practiced as an orthopedic spine surgeon at the NeuroSpine Center of Wisconsin.

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