What is Degenerative Disc Disease?
Degenerative disc disease describes the normal aging of the discs, or cushions, between the spinal vertebrae. This occurs naturally and is present in 20-30% of people at age 30, 60% at age 50, and almost 100% at age 70. Degenerative disc disease occurs because as the spinal discs age, they begin to lose their water content and the cartilage begins to wear out. This occurs most commonly in the cervical (neck) and lumbar (lower back) spine although it also does occur in the thoracic (mid back) spine. Importantly, most people do not develop neck or back pain as a result of degenerative disc disease although for largely unclear reasons some people do.
Degenerative Disc Disease Causes
Degenerative disc disease is universal and is caused by the normal aging process that happens to everyone with time. However, there are certain factors that are believed to accelerate this process. There is strong data for some of these factors and weaker data for some other factors.
Genetics certainly plays a role and patients whose parents had severe degenerative disc disease at a young age are likely to have similar degeneration at a young age. Patients that are overweight place more stress on their spines and have a predisposition to earlier degeneration. Smoking is also strongly associated with early onset degenerative disc disease due to the toxic effect of the smoke itself as well as the vasoconstrictive properties of nicotine, which reduces the blood supply to the spinal tissues and discs.
Degenerative Disc Disease Symptoms
In most people, degenerative disc disease is asymptomatic and is not associated with pain, weakness, spinal deformity, or any other symptoms. However, some patients do develop neck or back pain from degenerative disc disease for unclear reasons. Patients that are less active, have poor core and back flexibility and strength, are overweight, actively smoke, or have co-existent mood disturbances (anxiety or depression) are more likely to have neck or back pain from degenerative disc disease. Degenerative disc disease can also in some cases cause a spinal deformity such as scoliosis or kyphosis that is usually mild, but occasionally can be severe and require surgical stabilization. In some cases degenerative disc disease can contribute to decreased space available for the nerves (spinal stenosis) which can cause radiating pain down one arm or leg (radiculopathy) or sometimes pain or weakness down both legs with walking (neurogenic claudication). In the neck it can also sometimes cause spinal cord compression which can lead to difficulty with hand dexterity and with balance (myelopathy).
Diagnosis of Degenerative Disc Disease
Degenerative disc disease is present in everyone after a certain age. Most patients present to a physician with complaints of back pain, leg pain, numbness or tingling, or all of the above. If the main symptoms are back pain, the primary goal of the visit with a physician or spine surgeon is to rule out dangerous pathologic causes of the symptoms such as a fracture, tumor, or infection that is causing the back pain. This is done first with a detailed history and physical exam, and often also with standing radiographs (x-rays) of the spine. This information is usually sufficient to begin treatment. If symptoms persist despite 6 weeks to 3 months of conservative treatment, there is a progressive neurologic deficit, or there is concern for more serious underlying pathology (fracture, tumor, infection) then an MRI is obtained for further evaluation.
Degenerative Disc Disease Treatment
The treatment of degenerative disc disease with primarily neck or back pain symptoms without signs of neurologic compromise is conservative with minimal, if any, role for surgical treatment. This consists of a regular low impact exercise program (20-30 minutes daily of brisk walking, cycling, swimming, etc.), maintaining weight within a normal range, and smoking cessation (if an active smoker). Physical therapy is beneficial to help with postural training, hamstring flexibility, core strength, and lower back and pelvic stabilization. Acupuncture, dry needling, massage, and yoga can all also be beneficial. Medications such as non-steroidal anti-inflammatories (NSAIDS) and muscle relaxers can be used sparingly and often are helpful for acute flares of pain. Opioid medications are not helpful, and can be addictive and thus should be avoided.
Degenerative disc disease pain that is primarily from nerve or spinal cord compression such as arm pain, leg pain, numbness, weakness rather than primarily neck or back pain often is amenable to degenerative disc disease surgery if conservative measures have not helped. The precise type of operation depends on patient specific factors, the nature of the symptoms, and the precise location of the nerve or spinal cord compression and is determined after a thorough evaluation and in close conjunction with the patient’s wishes.