Degenerative Disc Disease DDD

 

Degenerative disc disease (DDD) is the name given to the process of early aging of the discs in the neck and back. The intervertebral discs and facet joints make up the articulations or joints that exist between each vertebrae. Scientists and physicians refer to these joints as motion segments. The disc accounts for roughly 2/3 of the stability of the motion segment, with the facet joints counting for most of the balance. As we age discs dry out. This is a natural process of senescence, but in some people the process is sped along by genetic factors, sports, trauma, and work environment. This process is usually pain free, but for some unfortunate people, it can lead to debilitating pain. Typically, patients with symptomatic disc degeneration complain more of neck or low back pain than of radiating arm or leg pain.

 

 

Spine Anatomy

The spine is divided into cervical, thoracic, lumbar, sacral and coccygeal regions. The spine is mobile through discs that separate each vertebrae. The spine allows flexibility of the neck and trunk, and serves to protect the spinal cord, essentially the electrical conduit through which nervous impulses pass from the brain to the rest of the body. Each vertebrae is comprised of a body (corpus) in front of the spinal canal, columns called pedicles on either side of the canal, and transverse processes,lamina, spinous processes, and facets in the back of the spine.

 

The cervical spine is the part of the spine that connects the head to the trunk. There are 7 vertebra within the cervical spine. The cervical spine is very mobile, leading to this part of the spine being a frequent source of pain as a result of wear and tear. The thoracic spine is the part of the spine to which ribs attach; there are usually 12 thoracic vertebra. The attachment of ribs to the spine causes this region to be relatively inflexible, and as a result there are few significant degenerative problems within this area. The lumbar spine is the mobile area below the thoracic spine; there are typically 5 lumbar vertebra. Most low back motion occurs here, and as a result degenerative changes and trauma in this area lead to many complaints of low back and leg pain. The sacral and coccygeal regions connect the spine to the pelvis and legs. Essentially no motion occurs in these areas, and therefore rare degenerative changes are seen here.

Disc Anatomy and Aging

The disc is composed of two primary components: the inner nucleus and the outer annulus. The nucleus is a gelatinous substance which provides the majority of shock absorption and disbursement of forces that pass through the spine. The annulus is a leather-like surrounding rim made up of multiple layers that provides structural support, resisting rotational and translational forces. Over time, the nucleus begins to desicate, or dry out, reducing its ability to absorb shock.

The forces that are normally placed through the spine, such as when lifting, bending, twisting, begin to be borne by the annulus and facet joints more than by the disc, resulting in formation of bone spurs (osteophytes) along the rim of the vertebrae. Cracks begin to develop within the layers of the annulus. Healthy discs are normally without blood supply, deriving their nutrition from the vertebra above and below. They also have very little nerve supply, with only the outer 1/3 of the annulus of a healthy disc being innervated. As the process of DDD progresses, and cracks develop in the annulus, blood and nervous tissue begin to invade the disc. At the same time, cartilage that lines the facet joints (the facets are paired for each disc, and reside behind or posterior to the discs) begins to erode, resulting in arthritic changes (spondylosis), stiffness, and sometimes pain. Over time, the disc begins to lose height, and like a flat tire, begins to bulge. A forceful bending injury, a twisting injury, or sometimes much less trauma can lead to a rupture of the annulus, allowing the nucleus to displace (herniate) backwards into the spinal canal. This is a very common injury, which may lead to neck or back pain, spasms in the muscles in the neck or back, and even radiating pain into the arms or legs. In the most severe cases, weakness and difficulty controlling the bowel or bladder may result. Other causes of neck and back pain exist as well. A simple muscle injury (strain) is very common, resulting in short term neck or back ache. A break or fracture of the vertebra, from trauma or osteoporosis, can lead to similar symptoms. A tumor within a vertebrae, or pressing on the nerves or spinal cord can cause pain. Abdominal problems such as aneurysms within the aorta can cause back pain.

Resolution of Neck and Back Pain

Most people who develop neck or back pain will have resolution of that pain within 6 to 12 weeks. For milder pain that doesn’t resolve within that period of time, severe pain, or if other symptoms such as constant tingling, numbness, weakness, or bowel/bladder symptoms develop, further treatment by an orthopedic spine specialist is appropriate. Diagnostic work-up and treatment are dictated by the presenting symptoms. Neck or back pain, mild numbness, mild radiating radiating arm or leg pain can be treated with analgesics such as naproxen (Aleve), ibuprofen (Advil), or acetaminophen (Tylenol), heat, ice, and gentle stretching. Physical therapy is appropriate, as is a short course of chiropractic. If symptoms persist despite these measures, further imaging studies such as X-Ray, MRI, and CT scanning may be appropriate. Mild narcotics, mild anti-spasm medicines, and even a short course of oral steroids occasionally improve symptoms. If not, typically the next step in the treatment of Degenerative Disc Disease, DDD, is consideration of epidural steroid injections. These injections are used to target inflamed tissue with potent anti-inflamatory medication. This may result in reduction in swelling of nerves, that may lead to improvement in neck, back, arm or leg pain. These steroids are different from anabolic steroids frequently discussed in the news to improve athletic performance. Serious side effects to steroid injections are rare, but it is important to understand that only about 50% of injections provide relief of pain. It is reasonable to have 3 or 4 injections a year for persistent pain, but continued use of injections only makes sense if prolonged relief of pain is achieved with each shot.

Most patients who have ongoing pain despite these efforts should be encouraged to participate in life-long, non or minimal-impact loading aerobic exercise such as walking, biking, using an elliptical machine, or better yet, swimming. Smoking cessation is crucial, as many studies have conclusively shown that smokers have a much higher incidence of low back and neck pain compared to non-smokers. Carrying extra weight can significantly negatively affect low back problems; weight loss combined with aerobic exercise provides the ideal route to improvement in overweight patients.

Surgery

Surgery may be a reasonable option for those few patients who have not responded to time, medications, therapy, chiropractic, and injections. Neck pain without arm symptoms is an exception to this general rule. Few patients respond well to surgery for isolated neck pain. In general, patients with isolated neck pain should live with these symptoms as long as possible before considering surgery. If studies show isolated single level (or possibly two level) disc degeneration in the cervical spine, a fusion has a chance of improving these symptoms, but the odds are only about 50:50 for good results. In general, surgery for DDD is more predictable at relieving arm or leg symptoms than neck or back symptoms. Many surgical options are available, and will be discussed in other areas of this web site. In general, nerves may be decompressed to relieve arm or leg pain, discs may be replaced, or fusion across the diseased and symptomatic motion segment(s) may be performed.

Home
Make An Appointment
Services & Treatments