Spinal Surgery Not Always the Best Choice for Low Back Pain

Low back pain affects four out of five people at some point in their lives, according to the American Academy of Orthopaedic Surgeons. The pain and discomfort - which typically stem from strained, stressed muscles and other soft tissues around the spinal column - generally go away after a few days or weeks of rest, gradual resumption of activities and avoiding overuse that can aggravate those soft tissues near the spine.

But in some cases, the pain persists longer than a few months, or the patient experiences nerve pain that radiates to the hip and legs. Then, surgery may provide some relief.

Low-back surgery, however, should only be performed in a relatively few, well-chosen cases, emphasizes Raj D. Rao, MD, Associate Professor and Director of Spine Surgery in the Department of Orthopaedic Surgery at the Medical College of Wisconsin - and only when non-invasive methods such as over-the-counter pain medications, plus stretches and exercises prescribed by a physical therapist, have been tried, but failed to provide relief.

When Surgery Might Help
When is low-back surgery indicated? Dr. Rao lists these major indicators:

Pain. "By far, long-term pain is the most common reason," he notes, adding that definitions of pain can vary widely among patients. "Pain is a highly subjective term, and everyone's tolerance for pain is different." The type of pain that indicates surgery is not everyday pain, but serious, unrelenting pain that interferes with daily activities and interrupts sleep. When pain reaches that level of intensity and persists, surgery might provide relief - "but only if the surgeon feels the patient's outcome might be somewhat improved," Dr. Rao adds.

Nerve damage. When pain radiates from the low back into the leg, it usually indicates nerve involvement. In some cases nerve damage may rapidly worsen, causing patients to lose bladder and bowel control. This indicates an emergency requiring spinal surgery.

Spinal instability. When the bony structures of the spine (vertebrae) move excessively and become malaligned, the instability can often trigger pain. Vertebrae can become unstable through injury to the supporting structures of the spinal column or a condition called spondylolisthesis.

Spinal deformity. A deformity such as scoliosis - in which the spine curves abnormally from side to side - may require corrective surgery after the patient reaches a certain age, typically in late childhood or early puberty. In other cases, spines can become deformed at a single level, due to arthritis or other conditions.

Tumor or infection. Surgery is often required in these situations to help eradicate the disease, decompress the nerve tissues and restore the stability of the spinal column.

"Very few low-back conditions require surgery," Dr. Rao says, noting that some people become impatient and press for surgery - and some physicians may acquiesce. "Back surgery is sometimes overdone and ill-advised," he notes.

What Low Back Surgery Can Accomplish
"Patients need to understand what back surgery can do and cannot do," says Dr. Rao. "Patients often have an unrealistic expedition that they'll wake up from surgery feeling pain-free and 20 years younger. That will not happen." Here's what spinal surgery can do:

Unpinch a nerve. If a nerve is compressed - either because a disc has herniated, or arthritis has triggered a bony growth (called stenosis) - spinal surgery can remove the part of the disc or part of the bony spur that's pressing against the nerve and causing pain. If a large disc is pushing against the nerve, Dr. Rao does a procedure called a microdiscectomy. Through an incision that is often less than an inch long, a small amount of spinal bone is removed to visualize the underlying nerve tissue. The pinched nerve is gently moved to a side, and the underlying disc herniation removed.

Decompress the nerve sac at a specific level. If the nerve sac at a certain vertebrae level is being squeezed by a disc herniation or bone spurs and arthritis, a surgical procedure called laminectomy can help reduce the pain, and improve walking and standing ability. These surgeries are frequently done in the neck as well, says Dr. Rao, who performs many cervical (neck) surgeries as well as low-back procedures.

Stabilize the spine. For patients suffering pain stemming from spondylolisthesis or other destabilizing condition, surgery can internally "brace" or fuse the hypermobile vertebrae to reduce the instability. In spinal fusion surgery, known medically as arthrodesis, the surgeon joins two vertebrae by harvesting bone from the patient's hip or from sections of vertebrae that have been removed to decompress a nerve. Metal implants may be used to improve the chances of a successful fusion. In some cases, a spinal fusion may be performed along with a laminectomy.

Minimally Invasive Spine Surgery
In recent years - thanks to newer, specially designed instruments and sophisticated imaging equipment - surgeons have been performing some laminectomies and spinal fusion surgeries with smaller incisions than were used in the past. Dr. Rao prefers the term "minimal access spine surgery," which he says more accurately describes the technique. "Both types of surgery are invasive," he says. For patients, the smaller incision may produce less trauma to the soft tissues adjacent to the spine, and thus may mean a speedier recovery.

"This type of procedure isn't for everyone," he cautions. "It depends on what type of pathology is involved, the patient's overall health and age, and other factors." Although it does offer possible benefits, the imaging systems used in minimal access surgery may not give the surgeon as clear a view of the affected anatomy as conventional surgery does.

Disc Replacement
Another relatively new technique called disc replacement has been introduced in the United States. Like a hip or knee replacement, disc replacement removes a disc from between vertebrae and replaces it with artificial material. "We're qualified to do it at Froedtert Hospital," Dr. Rao says, "but I am very selective about who I would offer it to right now because the procedure is still new and unproven." If it works as it's designed to, the replaced disc should reduce wear and tear at the levels above and below the replaced joint, he explains.

"In theory, it sounds attractive, but I don't feel it's been in use long enough to judge the results. We still don't know for sure whether the deterioration that sometimes develops at the levels above and below a fusion is caused by the fusion or would happen anyway as part of the normal aging process."

Managing Expectations
Spinal surgery can alleviate - but not necessarily eliminate - pain caused by disc pressure in 90% of cases, according to a 2002 article in the Journal of the Southern Orthopaedic Association, and from stenosis in about 70% of cases. Younger patients generally have better outcomes than older patients; in older patients, symptoms may return, and require additional surgery.

"As a general rule," Dr. Rao says, "we have to be careful about quoting success rates. The patient's perception of success may vary considerably from that of the surgeon. A patient may expect low-back surgery will restore them to a pain-free, youthful existence," he notes, "but that's unreasonable. A surgeon's perception of a successful outcome may be nerve decompression and partial alleviation of pain.

"It's critically important for surgeons to have a thorough discussion of realistic outcomes before surgery," he continues. "A well-informed patient with appropriate expectations will generally recover well after surgery."

Barbara Abel
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.