Low back pain is among the most common reasons people seek medical attention and a major cause of lost productivity. In fact, a significant majority of the population can expect to experience at least one bout of it in their lifetime. Most episodes of low back pain stem from simple muscle strain and resolve within a relatively short period of time. However, another very common cause of back pain and leg pain is a condition called lumbar spinal stenosis.
According to Toledo Clinic orthopedic surgeon Kraig Kristof, MD, lumbar stenosis is typically a degenerative process related to arthritis and degenerative disc disease. Over time, the overgrowth of soft tissue and bone in the lumbar spine—the five vertebrae located between the rib cage and the pelvis—causes narrowing of the spinal canal and the openings through which nerve roots branch out from the spinal cord. As these passageways narrow, the nerve roots can become pinched. Also, degeneration of the vertebral discs can cause them to bulge at the back, causing narrowing of the spinal canal and compression of the nerves.
"This pressure on the nerve roots, called neurogenic claudication, can cause numbness and tingling in the lower extremities and a tight, cramping pain that extends from the low back, through the buttocks, and down the back of the legs," explains Dr. Kristof. "But the classic symptom of lumbar stenosis is the 'shopping cart sign.' When the person goes to the grocery store, the first thing he or she does is grab a cart and lean on it. This posture opens up the spinal canal slightly and improves symptoms. On the other hand, standing up straight and hyperextending worsens the symptoms."
Treatment of lumbar stenosis typically begins with conservative measures to manage symptoms, such as activity modification, physical therapy, medications, and various muscle stimulation techniques (e.g., transcutaneous electrical nerve stimulation, or TENS). If those methods don't work, the doctor may progress to lumbar epidural steroid injections or possibly facet injections (corticosteroid injections into the facet joints) to reduce inflammation related to the underlying arthritic problem. If conservative management doesn't achieve the desired results after approximately six to 12 weeks, surgical treatment is the next option.
"Surgery can take a variety of forms, depending on the cause," states Dr. Kristof. "One option is decompressive laminectomy, which is essentially removing the roof of the bone to allow more room for the nerve roots and soft tissue to expand. If scoliosis or mechanical slippage is involved, fusion can be done in addition to decompression to stabilize the spine. There are also both open and minimally invasive approaches that can be used, though not all patients are candidates for minimally invasive surgery."
Examples of recent advances in minimally invasive techniques include using a tubular retractor, which involves performing decompression through a small tube and is typically used for relatively mild cases. A TLIF, which stands for transforaminal lumbar interbody fusion, can be performed open or through a small incision and involves removing damaged disc material and placing a bone graft with a cage into the disc space to decompress the stenosis, restore disc height, and open up the canal. Fusion is also performed along the back of the treated vertebrae to stabilize them.
Surgery is very safe and effective. Over 90% of surgery patients report relief of leg symptoms, and fusion can be very effective for improving symptoms of mechanical instability. Potential risks of these procedures are, in large part, the same as those associated with any other surgical procedure, such as bleeding, infection, blood clots, and anesthesia-related risks. In rare instances, there is injury to the nerve, resulting in post-surgical numbness, tingling, and possible weakness. However, there is no risk of complete paralysis following surgery on the lumbar spine because the spinal cord ends at approximately the first lumbar vertebra.
Dr. Kristof emphasizes that the development of bowel or bladder problems, such as incontinence, in patients with lumbar spine stenosis is an absolute indicator of the need for surgery. This symptom should be considered an emergency and must be addressed right away.
"Post-operative recovery typically includes a three-day stay in the hospital and getting the patient walking right away—either that same evening or the following morning. Physical therapy for the next six weeks usually involves just getting up and walking. By six weeks, most patients are feeling pretty well, and they can add therapy later on to build their strength back up," notes Dr. Kristof.
Unfortunately, not much can be done to prevent lumbar spinal stenosis. It's a degenerative process that stems from both genetics and wear and tear. Plus, as we age, the water content in the discs of the spine naturally diminishes, so the discs no longer provide the same degree of cushioning and begin to collapse.
Weight loss can help improve symptoms, but there's often a "catch 22" to that approach: Patients need to exercise in order to shed excess pounds, but their back pain makes it very difficult to exercise.
The good news is, doctors have a wide range of treatment options available to them to help bring relief to patients with lumbar stenosis, ranging from conservative therapies to open and minimally invasive surgeries. "A lot of patients are fearful about spine surgery, but overall, it's exceedingly safe. It's what we're trained for, we do it on a daily basis, and it usually gets very good results," Dr. Kristof says.