Degenerative scoliosis

Degenerative scoliosis comes about as the result of degeneration in the disc space and paired facet joints posteriorly (in the back of the spine). As the joints degenerate they turn and create a bend in the back, resulting in the classic scoliotic curve.

Whereas idiopathic scoliosis is much more common in the thoracic spine (mid back), degenerative scoliosis is much more common in the lumbar spine (lower back). It occurs most frequently in people over 65 years of age.

Symptoms and diagnosis
Unlike idiopathic scoliosis, degenerative scoliosis can be a cause of back pain. The pain mainly results from degeneration in the joints leading to arthritis. However, there are a lot of people who have a degenerative scoliosis who have no pain, so it is not always a cause of pain. What needs to be decided is if the patient has a degenerative scoliosis that is causing pain, or if they have back pain and an incidental finding of scoliosis. Other causes of back pain first need to be ruled out (such as a typical muscle strain).

Back pain with degenerative scoliosis typically comes on gradually, and is associated with activity. The pain tends to be worse first thing in the morning, and tends to improve after the patient gets up and around for a while. Then, later in the day the pain tends to worsen. Patients are usually comfortable sitting and have more pain when they stand and walk. This is because the facet joints generate most of the pain, and facet joints have more loading (pressure) in the standing position. Sitting takes the stress and weight off the joints.

As the spine degenerates and the facet joints become arthritic they enlarge, and this can create narrowing of the lumbar spinal canal, or what is also known as lumbar stenosis. If the canal becomes compromised enough, it can result in neurogenic claudication, or leg pain when the patient walks. This is because in the standing position the canal is even further narrowed, whereas when the patient sits back down this opens the canal up and relieves the leg pain. The stenosis probably produces leg pain because it prevents the blood supply from leaving the nerve root and causes engorgement around the nerve. A sitting position opens up the space and allows the blood to flow out.

The pain is very similar to osteoarthritis since the two conditions are essentially the same, except the scoliosis also has a deformity associated with it.

Conservative treatments
There are a lot of conservative care treatment options for patients with back pain and a degenerative scoliosis, including:

Medications. NSAID's (such as ibuprofen or Celebrex) can help reduce inflammation. Acetaminophen (e.g. Tylenol) is also an excellent pain reliever.
Epidural injections or facet injections. Injections, in which an anti-inflammatory medication and/or numbing agent is injected directly into the affected area, can be used to decrease acute inflammation in the back.
Physical therapy. It is important to keep the soft tissues and joints limber, and a physical therapy program can provide an appropriate stretching routine.
Pool therapy (water therapy). In water there is no gravity creating stress across the facet joints, so stretching and exercising will create less discomfort but still provide conditioning for the patient.
Chiropractic or osteopathic manipulation. Adjustments and manipulation can keep the facet joints mobile and help reduce pain.
Weight loss. Losing weight helps decrease stress across the facet joints.
Bracing. Rarely, a corset brace may be required to help eliminate motion in the back to decrease stress across the facet joints.

Any one of these treatments—or a combination of them—may be tried to decrease back pain. The emphasis of treatment should not be on becoming pain free, but on managing the pain and allowing the patient to stay functional and maintain daily activities. There is no cure for degeneration and arthritis in the spine, so there is no absolute way to fix the condition.

Scoliosis surgery
For those who cannot stay functional despite aggressive conservative treatment, surgery may be considered. Most patients will not need surgery for their scoliosis, as the curves tend to either not progress or to progress at a very slow rate. The progression is typically no more than 1 to 3 degrees per year, so it takes many years of observation to see any significant progression of the curve in an adult. Also, because the curve is in the lumbar spine, progression of the curve is very unlikely to influence the lungs or heart (as it would in the thoracic spine). Therefore, unlike surgery for idiopathic scoliosis, the goal of surgery for degenerative scoliosis is not to prevent deformity as much as it is to treat pain.

Probably the most common indication for surgery is to treat the associated lumbar stenosis and neurogenic claudication (e.g. leg pain when the patient walks). Decompressing the spinal nerves, however, can result in further instability and a progression of the curvature, so a spinal fusion procedure is done in conjunction with the decompression.

As with idiopathic scoliosis, the surgery involves fusing the involved portion of the spine to stop the motion at the affected joints. Some correction of the spinal curve can usually be gained during the surgery. (See also Idiopathic scoliosis surgery.)

Potential risks and complications
Adult degenerative scoliosis is more difficult than adolescent scoliosis surgery for several reasons.

The patients are older and tend to have other medical problems, which leads to an increased chance of a peri-operative medical complication
Often, because the patients are older, osteoporosis is also present and this makes gaining purchase in the bone with spinal instrumentation systems a difficult process.
Fusing the lumbar spine at multiple levels often requires a surgical approach from both the front and back to get a solid fusion. Also, the fusion may need to be carried to the sacrum, and getting a solid fusion to heal for this area is very difficult.

Given these factors, the surgery is often a large procedure with potential for a lot of blood loss and other associated risks, and it is not at all uncommon for the patient to require blood transfusions postoperatively. The procedure usually takes the better part of a day to complete (6 to 12 hours). Sometimes the surgery is staged, with the anterior fusion done first, then days to weeks later the posterior portion is done.

Other risks include:

Excessive blood loss
The rods breaking or the hooks dislodging (especially if the patient is osteoporotic)
Infection
Cerebrospinal fluid leak
Failure of the spine to fuse
Continued postoperative pain
Neurological injury

However, as with any surgery for back pain, the biggest risk is that despite undergoing a large spinal fusion surgery, the patient may still have debilitating pain after the surgery. Success rates significantly improving the patient's level of pain with this type of surgery are usually only about 60% to 70%.

It can take anywhere from 3 to 12 months to improve after surgery, so only the patients with the worst symptoms and marked activity limitations should consider surgery. The one time in which surgery may be considered sooner rather than later is if the curve has demonstrated a progressive tendency over a period of time and the patient is still relatively young (e.g. 55 to 65 years old). Doing the surgery while the patient is still healthy and young has some merit because he or she will be better able to tolerate the procedure. However, this is still often a very tough call and a decision to proceed with surgery should only be made after careful consideration.

By: Peter F. Ullrich, Jr., MD
September 17, 2001