Lumbar Degenerative Disc Disease
Lumbar degenerative disc disease is a common cause of chronic lower back pain. This occurs when a disc weakens, often due to either general wear and tear or a torsional (twisting) injury to the disc space. The result is excessive micro-motion at the corresponding vertebral level because the disc cannot hold the vertebral segment together adequately. The resulting micro-motion, combined with the inflammatory proteins inside the disc that become exposed and irritate the local area, can create lower back pain.
There is some confusion over the term “degenerative”, which implies that the symptoms will worsen with age. Although the disc degeneration will likely progress, the symptoms (pain) that result from it typically does not worsen, but in fact usually gets better over time. A fully degenerated disc no longer has any inflammatory proteins and usually collapses into a stable position. While many people over the age of 60 have degenerated discs, it is highly uncommon for them to suffer from pain caused by this condition. The end stage of the disc degeneration is re-stabilization as the disc stiffens, and this can lead to less pain. It is, however, a process that typically takes many years (as much as 20-30 years).
The typical individual with degenerative disc disease is an active and otherwise healthy person who is in their thirties or forties.
- The pain is generally made worse with sitting, since in the seated position the lumbosacral discs are loaded three times more than when standing
- Certain types of activity will usually worsen the pain, especially bending, lifting and twisting
- Walking, and even running, may actually feel better than prolonged sitting or standing
- Patients will generally feel better if they can change positions frequently, and lying down is usually the best position since this relieves stress on the disc space
- The degree of pain will usually fluctuate and may be quite painful at times (e.g. for a few days, or weeks) and then subside to a more tolerable level
In addition to low back pain, there may be leg pain, numbness and tingling. Even without pressure on the nerve root (a “pinched nerve”), other structures in the back can refer pain down the buttocks and into the legs. The nerves can become sensitized with inflammation from the proteins within the disc space and produce the sensation of numbness/tingling. Generally, the pain does not go below the knee. These sensations, although worrisome and annoying, rarely indicate that there is any ongoing nerve root damage. However, any weakness in the leg muscles is an indicator of some nerve root damage.
A Magnetic Resonance Imaging (MRI) scan is the best test to determine whether or not there is disc degeneration. However, not all degenerated discs cause pain, so simply seeing the condition on the scan does not necessarily indicate the presence of this condition. Experiencing the above symptoms, in conjunction with findings from a clinical exam and MRI scan, is a good indication that this condition is causing the pain.
Conservative (non-surgical) treatments
In most cases, degenerative disc disease can be managed with conservative treatments. Patients with this condition tend to experience pain that occasionally intensifies, but as long as the pain is manageable overall, surgery can usually be avoided.
A consistent exercise program can help maintain stability in the problem area, so the excess movement and pain are lessened. Exercises that can be helpful include:
- Hamstring stretching
- Dynamic lumbar stabilization exercises and other strengthening programs
- Low-impact aerobic conditioning
Patients should consider visiting a physical therapist to learn how to do these types of exercises safely and effectively.
Non-prescription medications, such as ibuprofen (e.g. Advil, Nuprin, Motrin) to reduce inflammation, and acetaminophen (e.g. Tylenol) for its analgesic (pain-relieving) qualities, may be helpful in alleviating lower back pain. Stronger therapies, such as oral steroids or epidural steroid injections, may be prescribed to treat severe flare-ups of pain if needed. Narcotic drugs (e.g., Vicodin, Percocet, OxyContin) can also be used sparingly during severe flare-ups, but should generally be avoided as a primary means of controlling chronic pain.
Other common treatment options include manual manipulation by a chiropractor or other qualified health professional, electrical stimulation (e.g. a TENS unit), and application of ice and/or heat to the affected area.
In more serious cases, patients may be in severe pain and may be unable to function due to the pain. In such cases, lumbar fusion surgery or artificial disc replacement are options.
A spinal fusion surgery is designed to stop the motion at a painful vertebral segment, which in turn should decrease pain generated from the joint. All lumbar fusion surgeries involve adding bone graft to an area of the spine to set up a biological response that causes the bone graft to grow (fuse), causing two vertebral bodies to grow together into one long bone, and thereby stop the motion at that segment. Bone graft can be taken from the patient’s iliac crest (autograft bone) during the fusion surgery, or harvested from cadaver bone (allograft bone). Synthetic bone graft substitutes (such as bone morphogenic proteins) are also being used for certain fusion procedures.
In general, a lumbar spinal fusion is most effective for treating only one vertebral segment. Most patients will not notice any limitation in motion after a one-level fusion. Fusing two segments may be a reasonable option for treatment of pain, but fusion of more than two segments is infrequently indicated because it removes too much of the normal motion in the back, placing too much stress across the remaining joints.
Artificial disc replacement is a newer surgery to treat pain and disability from lumbar degenerative disc disease. The theory is that replacing the disc, instead of fusing the disc space together, maintains more of the normal motion in the lumbar spine, thereby reducing the chance that adjacent levels of the spine will break down due to increased stress. This procedure is relatively new in the US, so long-term efficacy, and potential risks and complications, are still relatively unknown.
Surgery should only be considered after conservative treatment has been proven to be ineffective, and if the patient is truly limited by the degree of pain they experience.