Back pain is one of the most common health problems in the United States, affecting about 80 percent of American adults at some time in their lives. But "back pain" is a general term referring to pain that can come from a variety of causes--including sprains, strains, degenerative disk disease, osteoporosis, facet joint arthritis, spondylolisthesis, a herniated disk, hip problems and (rarely) cancer. Over-the-counter pain relievers are often sufficient to handle minor aches and pains, or the simple muscle strains incurred by the "weekend warrior" on the basketball court. However, back pain also can result from chronic, recurrent or even progressive conditions that are more serious and potentially disabling if not treated properly. It's important to know what is contributing to your back pain so you can work with your doctor to design an effective treatment plan.

Anatomy of the Spine

  The spine is composed of 33 vertebrae from the base of the skull to the tip of the tailbone. Between them are the cartilage disks that keep your spine flexible and cushion the hard vertebrae as you move. Below the lumbar spine is the sacrum, which is part of the pelvis, and the coccyx, or tailbone. The spine has two natural curvatures. Also, there are 31 pairs of nerves that branch off the spine into the arms and legs, 40 muscles, and numerous connecting tendons and ligaments.

The Degenerative Process
in the Spine

   A healthy back is mechanically balanced and stable. However, as we age we tend to develop conditions that contribute to spinal instability and lead to back pain. The spine is composed of bony vertebrae cushioned by cartilage disks. These "shock absorber" disks are composed of 90 percent water. As we grow older, they tend to dry out and gradually get thinner, flattening into a wafer-like shape. This results in decreased disk integrity, loss of disk height, and bulging of the outer portion of the disk (annulus fibrosis). The small joints (facet) in the back also undergo degeneration, resulting in their enlargement and bone spurs (osteophyte formation). This results in a narrowing where the nerve roots exit the spinal canal. Often, this lumbar degeneration also results in instability of the areas involved because of the change of the mechanical support. This can result in subluxation or spondylolisthesis of one vertebral body moving forward upon the segment below it. These deformities can worsen the nerve root irritation and compression of the stenosis. Simply defined, spinal stenosis is a reduction in the size of the spinal canal.

  Symptoms of spinal stenosis include a long history of back pain with discomfort in the back, buttocks and/or legs. It usually gets worse when you stand, walk or exercise in an erect posture. This results in pain, tightness, heaviness and/or subjective weakness in the legs. This symptom complex is referred to as "neurogenic claudication."

  Nerve impingement caused by stenosis in the spine is a common cause of sciatica. Sciatica is a symptom, not a diagnosis--it can result from any one of the many causes of back pain. Degenerative changes in the spine are often caused by osteoarthritis, wear and tear of the joints, which results in pain and stiffness. Spinal stenosis does not appear until nerves are affected. Unless leg pain as described above is present, the diagnosis has not progressed to the point of spinal stenosis.

Diagnosis of Spinal Stenosis

   Many common conditions can be confused with spinal stenosis, including peripheral vascular disease, degenerative arthritis of the hip or knee, and diabetic neuropathy. The correct diagnosis can be made with a careful history, physical exam and appropriate diagnostic studies. One way to suspect you might have spinal stenosis is that you feel more comfortable walking hunched over than standing up straight. This is because the spaces within the vertebrae through which nerves pass are constricted as the degenerative process narrows them and bone spurs develop. Walking bent over temporarily opens up more room inside for the nerves to pass, and, therefore, feels more comfortable. This sustained position can result in more problems with poor posture and strain to other parts of the body.

  I use imaging studies to confirm the diagnosis of spinal stenosis. Regular x-rays are essential; MRI, in combination with CT scan, is necessary to show nerve compression. A test called electromyography (EMG) may be ordered in some cases if the patient reports leg pain, or to help differentiate whether the symptoms are due to spinal stenosis or diabetic neuropathy.

Conservative Management

   In mild to moderate cases, spinal stenosis can be relatively stable. Patients do best with a comprehensive treatment plan that includes a combination of strengthening and flexibility exercises, use of heat and cold, joint protection including weight control, anti-inflammatory medication, analgesics and, sometimes, muscle relaxants and antidepressants.

  Physical therapy should consist of low-back exercises in combination with pelvic stabilization and aerobic conditioning. Aerobic conditioning can improve overall muscle tone and balance, and can assist in weight loss. A stationary bicycle is often ideal because it puts the spine in flexion. Walking is encouraged if it can be tolerated, and water exercise is often beneficial, especially in patients who also have hip or knee arthritis. Additionally, a lumbar brace may be helpful at times, but should only be used occasionally since it can cause deconditioning.

  If symptoms of lumbar stenosis persist, a series of epidural steroid injections (nerve blocks) can decrease inflammation in the nerves and relieve pain. This is usually a three-injection course of cortisone. I generally use epidural steroids in mild to moderate cases. If one or two injections are effective, a third may be done later, if the effect is wearing off. After the injections, patients should take advantage of the relief to advance in their exercise program.

  Other therapies such as facet injection, nerve blocks, manipulation, electrical stimulation, ultrasound and massage may provide some short-term relief, but are not effective in long-term management of spinal stenosis.

  These conservative treatment approaches may help forestall surgery for six months to a year, or in some cases even indefinitely. However, they only relieve symptoms and will not reverse or halt the progression of the degenerative process.

Surgical Treatment

   Patients who do not improve with these conservative treatments are likely to realize major benefit from decompressive surgery if they have moderate to severe spinal stenosis.

  Decompressive surgery (laminectomy) is appropriate for patients with neurogenic claudication and/or pain that significantly affects their quality of life. A thorough workup should be done preoperatively to identify associated changes, such as spondylolisthesis, spinal segmental instability or scoliosis, which might require stabilization or fusion. Factors associated with an unsuccessful outcome include osteoporosis, diabetes, repeat surgery or untreated instability.

  For a laminectomy, you might stay in the hospital for one or two days; with a fusion, four to five days. It takes a few weeks to get back to your normal activities after a simple laminectomy; adding fusion means a much longer recovery (several months). But you have to look ahead to where you want to be down the road: If you don't mind some short-term inconvenience for a long-term good result, surgery could be the way to go. Successful surgical treatment is seen in 80 to 85 percent of patients, and follow-up studies show that this improvement is maintained over the long term.

About the author:
Michael Winer, M.D. is an orthopaedic surgeon who specializes in traditional and minimally invasive spinal surgery. He is a member of the American Academy of Orthopaedic Surgeons, the American Association of Minimally Invasive Spinal Medicine & Surgery, and the North American Spine Society. Dr. Winer is affiliated with the Arizona Spine Care Alliance in Tempe, Arizona.

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