What is spinal stenosis?
Spinal stenosis is a disorder due to narrowing of the spinal canal that causes nerve and spinal cord impingement. This often results in persistent pain in the lower back and lower extremities. Difficulty walking, decreased sensation in the lower extremities, and decreased physical activity may also be seen. Spinal stenosis most commonly affects people over the age of 65, and scoliosis and hypertension are considered to be risk factors.
What causes spinal stenosis?
While some people are born with a small spinal canal, most spinal stenosis occurs when something causes the spinal canal to narrow. This could include:
- Overgrowth of bone: Wear and tear damage from osteoarthritis can prompt the formation of bone spurs, which can grow into the spinal canal.
- Herniated disks: The soft cushions that act as shock absorbers between your vertebrae tend to dry out with age. Cracks in a disk’s exterior may allow some of the soft inner material to escape and press on the spinal cord or nerves.
- Thickened ligaments: The tough cords that help hold the bones of your spine together can become stiff and thickened over time. These thickened ligaments can bulge into the spinal canal.
- Tumors: Abnormal growths can form inside the spinal cord, within the membranes that cover the spinal cord or in the space between the spinal cord and vertebrae.
- Spinal injuries: Car accidents and other trauma can cause dislocations or fractures of one or more vertebrae. Displaced bone from a spinal fracture may damage the contents of the spinal canal. Swelling of nearby tissue immediately after back surgery also can put pressure on the spinal cord or nerves.
The physician begins with a physical examination searching for tenderness over certain areas of the spine, as well as assessing the various limitations in movement of the lower extremity. The physician most likely will order radiological imaging, such as a CT scan or MRI, to visualize the level of stenosis.
The symptoms of spinal stenosis are caused by a squeezing of the nerve root. These symptoms occur most often in the legs, with people experiencing heaviness, weakness, and pain while walking or during prolonged periods of standing.
Standing or walking makes the symptoms worse due to pressure and stretching of the irritated nerves. When you take a rest, the symptoms often disappear because you've taken the pressure off the nerve roots.
There is adequate proof that acupuncture is more effective in treating neck and back pain than inactive treatments.
Epidural steroid injections
This procedure involves injecting a medication into the epidural space, where irritated nerve roots are located. This injection includes both a long-lasting steroid and a local anesthetic. The steroid reduces the inflammation and irritation and the anesthetic works to interrupt the pain-spasm cycle and nociceptive (pain signal) transmission. The combination medicine then spreads to other levels and portions of the spine, reducing inflammation and irritation. The entire procedure usually takes less than 15 minutes.
The procedure, also known as the Racz procedure, has proven effective in removing excessive scar tissue in the epidural space. Scar tissue originates from inflammation, irritation, and often surgery. A needle is inserted into the caudal epidural space (by the tailbone) and a catheter is advanced into the epidural space under fluoroscopic guidance. Corticosteroid, local anesthetic, wydase, and hypertonic saline are injected to aid in lysing (or breaking) the adhesions (scar tissue).
Spinal cord stimulation (SCS)
SCS involves implanting an electrical device that decreases the perception of pain by confusing the spinal cord and brain pain processing centers. Initially a trial is done to see if this device will help you long-term. In the initial trial, a small electrical lead is placed in the epidural space by your pain physician. Painful signals are replaced by tingling electrical signals. If you have success in your trial, you may decide to have a permanent SCS device implanted.
When all conservative measures have been exhausted and the symptoms continue to be severe, a more invasive surgical laminectomy or foraminotomy may be necessary to take pressure off the spinal cord and surrounding nerves. Often surgical decompression is recommended in acute spinal stenosis and especially in patients who rapidly develop loss of bladder/bowel function, weakness, and decreased sensation.
NSAIDs (ibuprofen-like drugs), membrane stabilizing drugs, and other analgesics are often used in the management of pain associated with spinal stenosis.