The lower part of your spinal column is known as the lumbar spine. This region contains 5 vertebral bodies connected by joints (intervertebral discs and facets). Within the column of bone and joints is a tunnel, the spinal canal, containing spinal fluid, and through which the spinal cord and nerves travel. Under normal conditions, the spinal canal is large enough for the spinal cord and nerves to pass freely without obstruction.
Lumbar stenosis is a narrowing of this spinal canal in your lower back, resulting in pressure on the spinal cord or spinal nerves. This pressure (pinched nerve) may cause symptoms such as pain, numbness, or tingling in the low back and legs. In more severe cases, there can be leg weakness or difficulty with bladder control.
The usual cause of lumbar stenosis is age-related wear and tear (arthritis) on the joints and ligaments of the spinal column. As these structures degenerate, they can become deformed, overgrown, or misaligned, crowding into and narrowing the canal where the spinal cord and nerves travel. The resulting stenosis can cause pressure to be applied on the nerves.
Lumbar stenosis can also be caused by disc herniations or fractures of the spine.
Rarely, stenosis can be congenital.
Risk factors for lumbar stenosis are the same as risk factors for any degenerative condition of the spine. These include:
- Family history of spinal arthritis
- Physically strenuous work, repetitive bending and lifting
- Repetitive trauma (collision sports)
- Sedentary lifestyle, especially excessive sitting
- Poor posture
- Muscular imbalance
Signs & Symptoms
The classic symptom of lumbar stenosis is leg pain or weakness made worse by standing upright or walking, and relieved by bending over or sitting. This is known as neurogenic claudication. Typically, patients with lumbar stenosis find it more comfortable to walk while stooped over, or while leaning on a cane or shopping cart.
Pain, numbness, and tingling can affect one or both legs. When severe, the legs may become weak after prolonged standing or walking. In extreme cases, there can be loss of bowel or bladder control.
Lumbar spinal stenosis requires a thorough evaluation by a spine-specialized practitioner. This evaluation will include a detailed history, physical exam, and neurological assessment.
History taking will identify when your symptoms started, inciting events (such as trauma or heavy lifting), relieving factors, symptom severity (numeric pain scale or visual analog scale), associated neurological symptoms (sensory loss, numbness/tingling, abnormal gait, bowel/bladder dysfunction, weakness), and attempted therapies (oral/topical medications, physical therapy, acupuncture, chiropractic etc.). A complete history helps your doctor recognize the pattern of your symptoms that can point to a likely diagnosis.
The goal of physical examination is to further clarify and isolate the cause of your symptoms. Leg pain and dysfunction can result from lumbar stenosis. But leg pain can also be caused by a variety of other derangements in your body, including in your brain, cervical spine, hips, knees, or soft tissues of your legs. After a careful history has suggested the likely pain generators, a detailed physical exam tests individual joints, muscles, and nerves to assess which ones are malfunctioning.
Depending on the history and physical, diagnostic imaging such as X-ray, CT scan, or MRI may be indicated for further evaluation. However, if symptoms are mild and acute (<4weeks), diagnostic images are usually not required in the initial evaluation.
For those patients who have moderate to severe symptoms, or symptoms lasting more than 4 to 6 weeks, especially after attempted conservative therapies, diagnostic imaging such as MRI (magnetic resonance imaging) or CT scan (computed tomography scan) may be considered to provide guidance for more interventional therapy. MRI without contrast is generally the best imaging study initially. For patients who cannot get an MRI, a CT scan can be obtained instead.
The majority of patients with lumbar stenosis can return to normal function without the need for surgery.
Nonsurgical treatments include:
- Temporary rest to reduce ongoing irritation
- Medications to relieve – Inflammation (Ibuprofen, Naproxen, steroids)
- Muscle spasms (Flexeril, Valium, Skelaxin)
- Nerve irritation (Neurontin, Lyrica)
- Pain (Morphine, Percocet, Dilaudid)
- Physical therapy to strengthen the core and improve postural biomechanics
- Epidural steroid injections to reduce inflammation at the spinal nerves
Surgery treatments focus on making the narrow spinal canal wider (laminectomy), thus relieving pressure on the nerves. Sometimes, if the spine is already unstable because of spondylolisthesis or advanced arthritis, spine fusion might be necessary in addition to decompression of the nerves
Lumbar stenosis is a common degenerative condition that creates pressure on nerves in the lumbar spine. The resulting leg pain and dysfunction may be mild or severe. Most cases respond well to conservative treatments such as rest, medications, physical therapy, and injections. In rare cases, surgery may be needed, and is very effective.