- Back or buttock pain
- Leg pain
- Weakness in the lower extremities
- Numbness or burning in the leg
- Bowel or bladder incontinence
Lumbar spinal stenosis refers to a set of symptoms related to narrowing of the spinal canal in the low back seen with aging and degeneration. The spinal canal is like a tunnel which runs up and down the human spine. This canal sits directly behind the bony blocks which make up the spine (vertebrae) and contains the nerves (spinal cord and nerve roots) running from the brain to all areas of the body. The nerves exit the lumbar spinal canal and travel through to the legs.
Stenosis is the gradual result of aging and “wear and tear” on the spine as well as a genetic predisposition. With age, the disc space decreases in height and bulges posteriorly toward the spinal canal. The facet joints and ligaments also enlarge and bulge toward the spinal canal. The ligaments of the spine can thicken and harden (calcification). Bones and joints may also enlarge when arthritis develops in the small joints of the spine (facets), and bone spurs (osteophytes) may form compressing nerves and the spinal canal. Spondylolisthesis, the slipping of one vertebra onto another, also may occur and lead to compression.
The symptoms of lumbar stenosis can be very mild or unnoticeable even when significant stenosis is present. This is because the spinal nerves have the ability to accommodate to some degree. If the nerves are being sufficiently pinched in the low back, the patient can experience unremitting buttock or leg pain (radiculopathy). When the neuroforamina are reduced in size due to surrounding buildup of tissue, the nerves react to the pressure by swelling, causing irritation to the nerves.
Alternatively, if enough compression of the spinal canal exists, multiple nerves can be “chocked off” with normal activities such as walking. Generally, patients with spinal stenosis are comfortable if they are sitting, but have more pain down their legs when they walk and the pain increases the more they walk. Standing upright further decreases the space available for the nerve roots, and can block the outflow of blood from around the nerve. Walking while leaning over a supporting object , such as a walker or shopping cart, can help ease the pain. Early in the process of stenosis, the buttock or leg pain is usually intermittent and activity related. When the spinal nerves continue to be squeezed, the damage may become progressive and less commonly, irreversible nerve damage can result. This condition, when it significantly affects the quality of living, can be treated surgically by removal of the offending discs, overgrown ligaments and bone.
Lumbar Stenosis Treatment
The first line of treatment is almost always non-surgical. The exception is when there is bladder or bowel incontinence or progressive weakness. A vast majority of patients suffering from leg pain will naturally recover given time and non-operative treatment. Non-operative treatments include strengthening exercises, physical therapy, chiropractic, acupuncture, traction, epidural injections, pain medications, and anti-inflammatory medications including steroids.
For buttock or leg pain and mild weakness (radicular symptoms), generally at least 6 weeks of non-operative treatment is pursued to monitor for natural recovery. The waiting period is based on the knowledge that 80-90% of radicular symptoms are known to spontaneously recover. If recovery is progressing, more non-operative treatment may be prescribed.
For isolated low back pain, generally at least 6 months of non-operative treatment is pursued to monitor for natural recovery. The waiting period is based on the knowledge that most midline low back pain is known to spontaneously recover within 6 months.
Surgical treatment for may be suggested to treat pain that has not responded to non-operative treatment or if there is severe neurologic deficit such as bowel or bladder incontinence or progressive weakness in vital muscle groups. With the exception of the presence of severe neurologic deficits, the decision to proceed with surgery is a quality of life decision.
Surgical options for a lumbar spinal stenosis are listed below. These surgical options often include a combination of surgical treatments (i.e. decompression, fusion, instrumentation). For a detailed explanation of the individual treatments, please visit the Surgical Treatments section of the web site.
1. Lumbar Laminectomy/Foraminotomy
With this procedure, the lamina and overgrown facet joints are removed to make room for the nerves. This is the most common treatment for lumbar stenosis where there is bilateral buttock/leg symptoms.
2. Lumbar Laminotomy/Foraminotomy
This procedure is used to remove part of the lamina and overgrown facet joint to relieve unilateral leg symptoms.
3. Lumbar Laminectomy and Posterior Fusion with Instrumentation
With this procedure, the compression on the nerves is relieved and the motion between the vertebrae arrested by placement of bone and instrumentation to hold the vertebrae together until they fuse. This procedure is helpful when there is abnormal motion between vertebrae (spondylolisthesis). Arguably, the instrumentation increases the chance of fusion.
4. Lumbar Laminectomy and Posterior Fusion without Instrumentation
With this procedure, the compression on the nerves is relieved and the motion between the vertebrae arrested by placement of bone to allow the vertebrae to fuse together. This procedure is helpful when there is abnormal motion between vertebrae (spondylolisthesis).
5. Minimally Invasive Procedures
Posterior foraminotomy can be performed through tubes. Laser decompression and disc removal have also been performed with mixed results.
6. Anterior Lumbar Fusion, Lumbar Laminectomy and Posterior Fusion with Instrumentation
In patients who develop severe deformities including lumbar flatback or lumbar scoliosis, a combined anterior fusion and posterior decompression and fusion with instrumentation may be necessary to restore the normal alignment of the lumbar spine. This procedure allows excellent restoration of the disc height which is helpful for restoring normal curvature of the spine and decompressing the narrowed foramen. The fusion rate is also shown to be higher than posterior fusion alone since there is additional surface area for fusion.
7. Lumbar Laminectomy, Lumbar Interbody Fusion, Posterior Fusion with Instrumentation
With this procedure, similar to the above procedures, the compression of the nerves is relieved and motion between the vertebrae arrested. In addition, the disc space height is restored which is helpful for restoring normal curvature of the spine and decompressing the narrowed foramen. The fusion rate is also shown to be higher than posterior fusion alone since there is additional surface area for fusion. The interbody procedure is also referred to as “PLIF” (Posterior Lumbar Interbody Fusion) or “TLIF” (Transforaminal Lumbar Interbody Fusion) based on how the interbody is approached.
Lumbar Stenosis Case Study
This 68 year old developed increased buttock pain especially when walking. She was previously very active, but over the past 6 months has not been able to walk more than ½ block without developing severe buttock pain necessitating her to sit.
Her MRI scan shows severe lumbar stenosis at multiple levels seen on both the sagittal scans (Images A & B). The red outlines the spinal canal. The blue outlines what a normal spinal canal would look like. Note the hour-glass tightness that occurs at the disc levels, especially at L2-3, L3-4, and L4-5.
The cross-sectional, axial scans (Images C & D) which show the severe tightness. Again, the red outlines the dimensions of the spinal canal, and the blue outlines what a normal spinal canal would look like.
A lumbar laminectomy resulted in her ability to walk up to 1 mile easily, and return to her position as a hospital volunteer. __