The lumbar spine (lower back) consists of five vertebrae in the lower part of the spine between the ribs and the pelvis. Lumbar spinal stenosis is a narrowing of the spinal canal which compresses the nerves traveling through the lower back into the legs. While it may affect younger patients due to developmental causes, it is more often a degenerative condition that affects people age 60 and older. The discs may become less spongy as you age, resulting in reduced disc height and bulging of the hardened disc into the spinal canal. Currently, it is estimated that about 400,000 Americans, most over the age of 60, may be suffering from the symptoms of lumbar spinal stenosis. There are as many as 1.2 million Americans with back and leg pain related to any type of spinal stenosis.
Lumbar spinal stenosis may or may not produce symptoms, depending on the severity of your case. The narrowing of the spinal canal itself does not produce these symptoms. It is the inflammation of the nerves due to increased pressure that may cause noticeable symptoms to occur. When present, symptoms may include:
Degenerative spondylolisthesis and degenerative scoliosis are two conditions associated with lumbar spinal stenosis. Degenerative spondylolisthesis (slippage of one vertebra over another) is caused by osteoarthritis of the facet joints. Most commonly, it involves the L4 slipping over the L5 vertebra. It is usually treated with the same conservative and surgical methods as lumbar spinal stenosis.
Degenerative scoliosis (curvature of the spine) occurs most frequently in the lower back and more commonly affects people age 65 and older. Back pain associated with degenerative scoliosis usually begins gradually, and is linked with activity. The curvature of the spine in this form of scoliosis is often relatively minor, so surgery is required when conservative methods fail to alleviate pain associated with the condition.
Diagnosis is made by a neurosurgeon based on your history, symptoms, a physical examination, and results of tests, including the following:
- X-ray: Application of radiation to produce a film or picture of a part of the body can show the structure of the vertebrae and the outline of the joints.
- Computed tomography scan (CT or CAT scan): A diagnostic image created after a computer reads x-rays; can show the shape and size of the spinal canal, its contents, and the structures around it.
- Magnetic resonance imaging (MRI): A diagnostic test that produces three-dimensional images of body structures using powerful magnets and computer technology; can show the spinal cord, nerve roots, and surrounding areas, as well as enlargement, degeneration, and tumors.
- Myleogram: An x-ray of the spinal canal following injection of a contrast material into the surrounding cerebrospinal fluid spaces; can show pressure on the spinal cord or nerves due to herniated discs, bone spurs or tumors.
- Anti-inflammatory medications to reduce swelling and pain, and analgesics to relieve pain. Most pain can be treated with nonprescription medications, but if your pain is severe or persistent, your doctor may recommend prescription medications.
- Epidural injections of cortisone may be prescribed to help reduce swelling. This treatment is not recommended repeatedly and usually provides only temporary pain relief.
- Physical therapy and/or prescribed exercises may help stabilize your spine, build your endurance, and increase your flexibility. Therapy may help you resume your normal lifestyle and activities.
Your doctor may recommend surgery if conservative treatment options, such as physical therapy and medications do not reduce or end the pain altogether. He or she will talk to you about the types of spinal surgery available, and depending on your specific case, will help to determine what procedure might be an appropriate treatment for you. As with any surgery, a patient’s age, overall health, and other issues are taken into consideration when surgery is considered.
You may be considered a candidate for spinal surgery if:
- Back and leg pain limits normal activity or impairs your quality of life
- You develop progressive neurological deficits, such as leg weakness and/or numbness
- You experience loss of normal bowel and bladder functions
- You have difficulty standing or walking
- Medication and physical therapy are ineffective
- You are in reasonably good health
There are several different surgical procedures which can be utilized, the choice of which is influenced by the severity of your case. In a small percentage of patients, spinal instability may require that spinal fusion be performed, a decision that is generally determined prior to surgery. Spinal fusion is an operation that creates a solid union between two or more vertebrae. This procedure may assist in strengthening and stabilizing the spine and may thereby help to alleviate severe and chronic back pain.
The most common surgery in the lumbar spine is called decompressive laminectomy in which the laminae (roof) of the vertebrae are removed to create more space for the nerves. A neurosurgeon may perform a laminectomy with or without fusing vertebrae or removing part of a disc. A spinal fusion with or without spinal instrumentation may be recommended when spondylolisthesis or scoliosis occurs with spinal stenosis. Various devices (like screws or rods) may be used to enhance fusion and support unstable areas of the spine.
Other types of surgery, including several methods of spinal fusion to treat lumbar spinal stenosis and associated conditions:
- Anterior Lumbar Interbody Fusion (ALIF): Removal of the degenerative disc by going through the lower abdomen. Bone graft material or a metal device filled with bone is then placed into the disc space.
- Foraminotomy: Surgical opening or enlargement of the bony opening traversed by a nerve root as it leaves the spinal canal, to help increase space over a nerve canal. This surgery can be done alone or together with a laminotomy.
- Laminotomy: An opening made in a lamina, to relieve pressure on the nerve roots.
- Laparascopic Spinal Fusion: A minimally invasive procedure involving small incisions in the abdomen, through which a graft is placed into the disc space.
- Medial Facetectomy: Surgical procedure to remove part of the facet (a bony structure in the spinal canal), to increase the space.
- Posterior Lumbar Interbody Fusion (PLIF): Removal of the posterior bone of the spinal canal, retraction of thenerves, and removal of the disc material from within the disc space, followed by insertion of bone graft and sometimes hardware in order to fuse the bones. This procedure is called an "interbody fusion" because it is performed between the “bodies” of the vertebral bones and across the diseased disc space. This procedure is typically performed on both sides of the spine.
- Posterolateral fusion: Placing bone on the back and side of the spine to achieve a fusion.
- Transforaminal Lumbar Interbody Fusion (TLIF): Removal of the posterior bone of the spinal canal, retraction of the nerves, and removal of the disc material from within the disc space, followed by insertion of bone graft and sometimes hardware in order to fuse the bones. Similar to a PLIF, but frequently performed from only one side.
The benefits of surgery should always be weighed carefully against its risks. Although a large percentage of lumbar spinal stenosis patients report significant pain relief after surgery, there is no guarantee that surgery will help every individual.