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Degenerative Disc Disease and Low Back Pain

Lumbar Spine Degenerative Disc Disease

Degenerative disc disease (DDD) is a gradual process that may compromise the spine. Although DDD is relatively common, its effects are usually not severe enough to warrant medical attention. In this discussion, we address degenerative disc disease in the lumbar (low back) spine.

Degenerative Changes to a Disc

Degenerative changes in the spine are often referred to those that cause the loss of normal structure and/or function. The intervertebral disc is one structure prone to the degenerative changes associated with wear and tear aging, even misuse (eg, smoking).

Long before degenerative disc disease can be seen on an x-ray, biochemical and histologic (structural) changes occur. Some of these changes are similar to those associated with osteoarthritis.

Over time, the collagen (protein) structure of the annulus fibrosus weakens and may become structurally unsound. Additionally, water and proteoglycan (PG) content decreases. PGs are molecules that attract water. These changes are linked and may lead to the disc’s inability to handle mechanical stress. Understanding the lumbar spine carries a large portion of the body’s weight; the stress from motion may result in a disc problem (eg, herniation).

 

disc herniation

 

Non-operative Treatments for Lumbar Degenerative Disc Disease

DDD is a disorder that may cause low back pain. It is interesting to note that although 80% of adults will experience back pain, only 1% to 2% will need lumbar spine surgery!

In the past, some physicians prescribed long courses of bed rest and/or lumbar traction for their patients with low back pain. However, that is not the attitude today. During the acute phase, bed rest may be recommended for a few days, but beyond that, experts advocate stretching, flexion and extension exercises, and no- or low-impact aerobics. Of course, each patient is different, and therefore so is their treatment plan.

Therapeutic Exercise
In some patients, the pain response may limit flexibility. Prescribed stretching exercises can improve flexibility of the trunk muscles. Flexion exercises may help to widen the intervertebral foramen. The intervertebral (between the vertebrae) foramen are small canals through which the nerve roots exit the spinal cord. The intervertebral foramen are located on the left and right sides of the spinal column.

 

physical therapist extending patient's leg

 

Extension exercises, such as the McKenzie Method, focuses on the muscles and ligaments. These exercises help maintain the spine’s natural lordotic curve, important to good posture.

Aerobics (no/low impact) offers many benefits including improved muscular endurance, coordination, strength, strong abdominal muscles, and weight loss. Strong abdominal muscles work like a brace (or corset) to reduce the loads to the lumbar spine. It is also known that aerobics help to combat anxiety and depression. The loads on the discs during walking are only slightly greater than when lying down. Walking, bicycling, and swimming are forms of aerobic exercise a physician may suggest.

Acupuncture
Acupuncture, a type of alternative medicine, has been shown to help control pain. It has been suggested that acupuncture stimulates the production of endorphins, acetylcholine, and serotonin. However, acupuncture should be combined with an exercise program for many of the reasons outlined in prior paragraphs.

Drug Therapy:  Medications for Degenerative Disc Disease
During the acute phase of low back pain, medications may be prescribed. Some may include acetaminophen, anti-inflammatory agents, muscle relaxants, narcotics, and anti-depressants. Narcotics are used on a short-term basis partly due to their addiction potential. When low back pain is caused by muscle spasm, a muscle relaxant may be prescribed. These drugs have sedative effects. Depression can be a factor in chronic low back pain. Anti-depressant medications have analgesic properties and may improve sleep.

Manipulation
Today manipulation is performed by chiropractors and physical therapists. For patients without radiculopathy (pain stemming from a spinal nerve root), manipulation may be effective during the first month. Thereafter, benefits are unproven. Manipulation is believed to be effective because of its effect on spinal mobility. Acute low back pain, chronic low back pain, and degenerative disc disease without nerve compression may respond to manipulation.

Treatment Plan Example:  The First Six Weeks
Usually during the first six weeks, acute low back pain is treated with a couple of days of bed rest (slightly longer with a herniated disc) and appropriate medication. Muscle relaxants are seldom used for longer than one week. Early ambulation is encouraged to increase circulation (aids healing), improve flexibility, and build strength.

Generally, during the first two to three weeks, acute symptoms subside. Aerobic (no/low impact) exercise may be started three times per week along with daily back exercises. Some patients may be referred to physical therapy or a supervised work-conditioning program.

Treatment Plan Example:  Beyond Six Weeks
If the symptoms of degenerative disc disease and low back pain persist despite non-operative treatment, further diagnostic tests may be necessary. These tests may include an MRI, CT Scan, myelogram, or possibly discography.

Although most degenerative disc disease patients with herniation respond well to non-surgical treatment, a small percentage do not. Disc herniation is the most common indication for spinal surgery. In fact, 75% of all spinal surgeries are for a herniated disc.

Red Flags that May Point to a Need for Spine Surgery

  • Lumbar (low back) herniation causing loss of bowel or bladder control, or major lower extremity deficit, requires immediate surgery. These symptoms are caused by nerve root compression.
  • Cauda Equina Syndrome is a serious disorder that may be caused by a large central herniation. The cauda equina begins at the end of the spinal cord. The cauda sac is filled with nerves resembling the tail of a horse. When this sac is compressed the patient may present with the following symptoms: low back pain, bilateral lower extremity weakness, radiculopathy (pain from a nerve root), and incontinence.

When these symptoms present, surgery is required immediately. Most herniated discs often do not require surgical intervention and respond quite nicely to non-surgical treatments (within 6 weeks).

Spine Surgery Options for Lumbar Degenerative Disc Disease

The type of surgical procedure depends on the patient, the diagnosis, and the treatment goals.

Surgical removal of a disc may involve a limited laminotomy and partial disc excision. The disc fragments are removed and the nerve is decompressed. Microdiscectomy is often a preferred procedure requiring smaller incisions. Benefits include smaller scars and a faster recovery.

If the entire disc is removed, fusion may be needed to stabilize the spine. Patients who are obese, smoke, or who have psychological problems experience lower rates of success. Smoking in particular negatively impacts the process of fusion and healing in general. Spinal fusion may be combined with spinal instrumentation (e.g. screws, cages).

In Conclusion
Although lumbar degenerative disc disease is relatively common in aging adults, it seldom means spine surgery. When medical attention is needed, most patients respond well to non-surgical treatment. If people stop smoking (all tobacco use), keep up with a regular fitness program and good diet, most can enjoy the benefits of a healthy spine.

Updated on: 01/16/13
Dr. Lowe has given an excellent description on the overall epidemiology natural history of degenerative disc disease and low back pain. As he so correctly mentioned, most back pain and degenerative symptoms do not require surgical intervention. Alternative treatments including medications, physical therapy and manipulation techniques improve symptoms tremendously over the first 6-weeks after the onset of symptoms. Beyond 6-weeks, more long term management may be required. If symptoms persist, then thorough diagnostic imaging studies would be required to adequately diagnose specific pain generators. If a disc herniation is identified and conservative care management does fail, then partial disc excision may be performed either through a small open or minimally invasive technique. When surgery is required on a degenerative disc, surgeons are currently trying to limit the morbidity of the surgical procedure by directly approaching the pathology. It makes little sense to remove a collapsing degenerative disc when that is isolated as a focal pain generator. Surgical reconstruction, including interbody fusion technique may be required either through an anterior or posterior approach. Disc replacement techniques including nuclear and total disc replacement may hold promise for failed degenerative disc treatment when intervention is required. Many of these techniques are undergoing FDA IDE clinical evaluation at this time.
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