Latest News On Disc ProblemsIt used to be that a bulging disc, herniated disc, or degenerating disc was very bad news. Surgery was often done and in many cases with less than satisfactory results. But much more is known about disc disease now. Better technology allows for earlier diagnosis and successful treatment without surgery. The authors of this review article bring us up to date on what's the latest with lumbar degenerative disc disease (DDD).
Degenerative disc disease is a problem usually linked with aging. Disc degeneration follows a predictable pattern. First, the nucleus in the center of the disc begins to lose its ability to absorb water. The disc becomes dehydrated. Then the nucleus becomes thick and fibrous, so that it looks much the same as the annulus (fibrous outer covering of the disc).
As a result, the nucleus isn't able to absorb shock as well. Routine stress and strain begin to take a toll on the structures of the spine. Tears form around the annulus. The disc weakens. It starts to collapse, and the bones of the spine compress. It's the compression of the soft tissues that probably causes painful symptoms.
What does the doctor look for to identify degenerative disc problems? Low back pain, of course. And pain that travels into the buttock, sacroiliac area, and/or down the leg. Symptoms might be worse first in the morning and with any kind of forward bending movement of the spine. But this isn't standard and there can be a wide range of symptoms.
Without a specific set of identifying symptoms, surgeons often say that it's easier to rule out other possible causes of back pain than it is to rule in disc disease. That makes degenerative disc disease a diagnosis of exclusion.
What can the patient with low back pain expect at the surgeon's office? The physician starts with a detailed history and careful physical exam. Imaging studies such as X-rays and MRIs all contribute to the diagnostic process.
X-rays help show fractures, bony alignment, disc space narrowing, and bone spurs. MRIs give a detailed view of the discs themselves. If the disc looks normal on an MRI, the physician looks elsewhere for the cause of the painful symptoms. But even with abnormal findings, it isn't certain that the disc is the problem.
Studies show that one-third up to one-half of all patients with disc degeneration have no pain or other apparent distress from these changes. To help doctors understand what findings on MRIs are helpful, the authors provide images and a detailed description of types and locations of signal intensity changes that point to painful internal disc disruptions as a possible cause of low back pain.
It is also possible to test the disc directly using discography. The disc is injected with a dye. The extra fluid in the disc increases pressure and causes pain if that's the painful area. If there's a tear in the covering around the disc (called the annulus), the dye will leak out.
The disadvantages of this test may outweigh the benefits, so it's not used routinely. Besides being painful, it can create new pain in discs that were previously fine. And for patients who have other chronic pain patterns (e.g., neck, arm, general body pain), the risk of a false-positive result is much higher. Surgery isn't always helpful even when the discography is positive, so the value of the test is limited.
Most of the time, patients with degenerative disc disease improve with conservative (nonoperative) treatment. In fact, up to 90 per cent of all patients with low back pain of some kind get better without any treatment at all. For that reason, immediate treatment isn't advised unless there are significant neurologic symptoms suggesting an emergency situation.
Medications such as antiinflammatories and antidepressants have been found helpful with certain patient population groups. Physical therapy is often the first-line of hands-on treatment. Core training of the trunk (abdomen and back) muscles is used to stabilize the spine. Patients are taught correct posture, lifting techniques, the importance of movement, and other specific exercises that are appropriate for each individual.
When there is acute (recent) low back pain, spinal manipulation by a physical therapist or chiropractor has been shown to be effective. Chronic low back pain requires a different approach altogether with a multidisciplinary team of experts addressing physical, social, emotional, and psychologic issues.
When conservative care fails to reduce pain or restore movement or function, then more invasive treatment such as electrothermal therapy, steroid injection, or surgery may be considered. Intradiscal electrothermal therapy (IDET) is the use of heat to destroy damaged disc tissue. It has a very low complication rate but also mixed results, so it's not widely used yet.
Steroid injections seem to provide short-term pain relief. In some patients, that may be all that's needed to get them back on their feet and moving. More studies are needed to better understand this treatment approach. It may be possible to identify subgroups of patients who would benefit the most.
Spinal fusion is still done but it has come under question lately. The procedure is invasive, provides inconsistent results, and low overall long-term satisfaction. Some studies showed that doing nothing had as much effect as having a fusion.
Like all treatments for low back pain patients, it works for some, but not all, patients. Finding those patients for whom fusion would work best may help narrow down the field and produce better results.
For now we know that the predictive factors of a poor outcome include previous surgery for back pain, low income, tobacco use, depression, older age, and lawsuits. Current research is focusing on type of fusion and whether some types (e.g., posterolateral, anterior, interbody) have better outcomes than others.
As a result of these mixed reviews for fusion, surgeons have turned their focus in other directions looking for a better solution. The latest development has been what's called motion-sparing technology. This refers to surgical procedures designed to preserve motion at the diseased level so that the adjacent segments don't start to degenerate, too.
There are several types of motion-sparing procedures including supportive rods placed alongside the spine, polymers (manmade plastics and proteins) injected into the disc, and total disc arthroplasty (disc replacements).
Disc replacements are fairly new in the United States. Only a small number of patients qualify for this operation. They must have a stable spine and disc degeneration (not a herniated disc). There must be no stenosis (narrowing of the spinal canal), osteoporosis (low bone density or brittle bones), or obesity. Women who are pregnant and anyone with scoliosis, previous lumbar fusion, spinal infection, or vertebral fracture are also not good candidates for disc replacement at this time.
But data on the results of disc replacements is starting to be published. Most studies are small in number. There are complications such as failure of the implant, fractures of the vertebral bodies, and subsidence (sinking) or migration (movement) of the implant. Researchers are keeping an eye on adjacent disease and following patients to get long-term results.
The authors say that the big picture view of degenerative disc disease is that it can take a while to sort out all the possible causes of low back pain before determining the cause. Surgery is only done when the condition causes chronic pain and loss of function. Spinal fusion is still the most common surgical treatment. New evidence from studies on disc replacements may change that in the future, but for now, it's a wait-and-see proposition.
Luke Madigan, MD, et al. Management of Symptomatic Lumbar Degenerative Disk Disease. In Journal of the American Academy of Orthopaedic Surgeons. February 2009. Vol. 17. No. 2. Pp. 102-111.
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