The lumbar spine consists of five vertebrae in the lower part of the back, located between the pelvis and ribs. The condition known as lumbar spinal stenosis is a narrowing of the spinal canal, causing the nerves traveling through the lower back into the legs to become compressed. Due to developmental causes, this condition may affect younger patients. However, it is more common in people aged 60 and older as a degenerative condition.
One’s spinal canal may narrow very slowly, typically over various years or decades. One’s discs become less spongy as they age, causing one to lose disc height. It may also trigger the bulging of the hardened disk into the spinal canal. Also, bone spurs may occur, and one's ligaments may thicken. All of these factors may contribute to narrowing of the central canal, and they may or may not produce symptoms. Such symptoms may be caused by inflammation, compression of the nerve(s), or both.
Such symptoms may include:
- Weakness, pain, or numbness in the buttocks, legs, or calves
- Cramping that appears in the calves with walking, requiring short but frequent rests to walk some distance
- Pain radiating into one or both legs and thighs, similar to the term “sciatica”
- In rare cases, loss of normal bowel/bladder function or loss of motor functioning of the legs
- Pain that may improve with bending forward, sitting, or lying down
Degenerative spondylolisthesis and degenerative scoliosis (curvature of the spine) are two conditions that may be 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 non-surgical (“conservative”) and surgical methods as lumbar spinal stenosis.
Degenerative scoliosis occurs most frequently in the lower back and more commonly affects people aged 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. Surgery may be indicated when nonsurgical measures fail to improve pain associated with the condition.
Based on history, symptoms, test results, and physical examination, a neurosurgeon makes his or her diagnosis.
Imaging studies used may include the following:
- CT (CAT) scan
Medications, stretching, time, posture management, and exercise can be helpful to many patients who experience pain flare-ups. Nicotine cessation, weight management, and bone-strengthening endeavors may also be beneficial.
- Anti-inflammatory medications may reduce swelling and pain. Analgesics can also be used as pain relievers. Iif the pain is severe or persistent, prescription medications may be provided, but most pain can be treated without prescriptions.
- To reduce swelling, epidural injections of medications may be prescribed.
- Physical therapy and/or prescribed exercises may help to stabilize and protect the spine, increase flexibility, and build endurance. Therapy may aid a patient in resuming normal activities. Four to six weeks of physical therapy are usually recommended.
Surgery may be recommended if non-surgical management fails to improve symptoms. Different types of spinal surgeries are available, so, for each specific case, a neurosurgeon will determine the most appropriate procedure for the patient. Like all surgeries, a patient’s risks, which include age, overall health, and other issues, are taken into account before the surgery.
A patient may be considered a candidate for surgery if:
- Back and leg pain impairs quality of life orlimits normal activity
- Progressive neurological deficits develop (leg weakness, foot drop, numbness in the limb)
- Loss of normal bowel and/or bladder functions
- Difficulty standing or walking
- Medications and physical therapy are not effective
- The patient is in reasonably good health
Several different surgical procedures can be utilized, the choice of which being influenced by each case’s severity. For a small percentage of patients, spinal instability may require spinal fusion, a decision generally determined before surgery. While performing a spinal fusion, a surgeon creates a solid union between two or more vertebrae. This operation may assist in stabilizing and strengthening one’s spine, thereby helping to alleviate severe and chronic back pain.
Types of Surgeries
The most common lumbar spine surgery is a decompressive laminectomy. In this operation, the laminae (roof) of the vertebrae are removed, forming more space for the nerves. A laminectomy may be carried out with or without removing part of a disk or fusing vertebrae. A spinal fusion, either with or without spinal instrumentation, can be used to support unstable areas of the spine and enhance fusion
Other types of surgeries or techniques/methods to treat lumbar spinal stenosis include:
- Laminotomy: Creates an opening in the bone (the lamina), relieving the pressure on the nerve roots
- Foraminotomy: Surgical enlargement or opening of the bony exit for the nerve root where it leaves the spinal canal; may be done alone or alongside a laminotomy/laminectomy.
- Medial Facetectomy: Removal of a part of someone’s bony joint (facet), which can be overgrown; intended to create more space within the spinal canal.
- Anterior Lumbar Interbody Fusion (ALIF): Removal of the degenerative disk as a surgeon goes through the lower abdomen. A structural device, made of carbon filter, bone, metal, or other materials is inserted to take the supportive place of the removed disk and packed with bone. This is done with the intention of the fusion between the bone (body of the vertebrae) above and below occurs.
- Posterior Lumbar Interbody Fusion (PLIF): By going through the skin on the back, the removal of one’s degenerative disc. Also the removal of the posterior bone of the spinal canal and retraction of the nerves to get to the disk space. A structural device, constructed of metal, bone, carbon filter, and other materials, is placed to take the supportive place of the removed disk and packed with bone. Ultimately, the fusion between the bone (body of the vertebrae) above and below occurs. Similar to TLIF, this is often done on both sides of the spine.
- Transforaminal Lumbar Interbody Fusion (TLIF): Removal of the degenerative disk by going through the skin on one’s back. Afterward, the removal of one’s posterior bone of the spinal canal and the retraction of one’s nerves to get to the disk space. A structural device, composed of metal, bone, carbon filter or other materials, is placed to take the supportive place of the removed disk and packed with bone. Ultimately, the fusion between the bone (body of the vertebrae) above and below occurs. Similar to PLIF, this is often done on only one side of the spine.
- Posterolateral Fusion: Places bone graft on the back and side(s) of the spine to achieve a fusion.
- Instrumented Fusion: Using “hardware”, such as screws, hooks, other devices, to add stability to the construction for fusion.
The potential benefits of surgery must be weighed carefully against the risks associated with surgery and anesthesia. Although a large portion of lumbar spinal stenosis patients who ultimately undergo surgery report significant pain relief after surgery, there is no guarantee a procedure will help all patients.