When people think of back pain, they often think of a "slipped disc." But what exactly is a disc, and how does it "slip?" More importantly, how are these injuries diagnosed and treated? This article will attempt to answer these questions.
What is a "slipped" disc?
The human spine is made up of 24 movable bones called "vertebrae." Discs are the shock absorbers between the vertebrae. There are six discs in the neck (the cervical spine), 12 discs in the middle and upper back (the thoracic spine), and five discs in the lower back (the lumbar spine).
Discs are made of cartilage and they are oval-shaped. It can be useful to think of discs like jelly doughnuts (except that discs are much firmer). The middle one-third of the disc contains a jelly-like material called the nucleus pulposus. The outer two-thirds of the disc is called the annulus fibrosus. The annulus is made up of tough rings of fibrocartilage that surround the inner nucleus. The top and bottom of each disc is made of a firm cartilaginous "endplate." These endplates are firmly attached to the vertebrae above and the vertebrae below. Therefore, discs don't really "slip."
Normally, the rings of the annulus are intact and hold the nucleus in the middle of the disc. However, with repeated injuries, the outer annular fibers can tear, allowing the jelly-like nucleus to seep through cracks and pinch sensitive nerves in the area. If the nucleus pushes against the outer wall of the annulus, the result is called a disc bulge. If it actually breaks through the outer wall and moves outside the disc, it can be referred to as a protrusion, prolapse, herniation or extrusion.
Causes of disc injuries
While there are many causes of disc injuries, the pain and inflammation associated with them usually occur as the "final straw" of many minor injuries that occur over a long period of time. Repeated improper bending and lifting, prolonged sitting with poor support, and trauma from car accidents and sports can all damage discs. Lack of proper flexibility and core strength also contribute. Smoking is a major risk factor for disc injuries since it reduces the disc's already limited blood supply.
Diagnosing disc injuries
When a disc becomes injured, the result can be pain, tingling, numbness, or weakness of the involved area. If the disc lesion is in the neck, one may experience symptoms down the arm to the hand and fingers. If the disc lesion is in the lower back, symptoms can go down the buttocks and leg to the foot and toes (when painful, this is known as "sciatica"). Examination of patients with these symptoms includes testing of reflexes, sensation and strength of the arms and legs. It also includes a variety of specific tests designed to reproduce the patient's pain by stressing the disc or involved nerve. Diagnostic imaging, especially MRI, is a valuable tool for arriving at an accurate diagnosis.
However, not all disc changes are relevant to the individual's symptoms. It is important to understand that just because there are findings on an MRI (spurs, arthritis, herniations, bulges, stenosis) it does not automatically confirm those changes as the cause of symptoms. The diagnosis must correlate with the examination. Also, there is almost always overlapping joint and muscle involvement, which can also contribute to radiating arm or leg symptoms. It has been demonstrated by several studies utilizing MRI and CAT-scans that disc changes from degeneration to large herniations occur in over 30 percent of individuals that have never had low back or leg complaints. But when the disc and or nerves are acutely pinched and inflamed it often causes problems.
Treatment of disc injuries
Once the correct diagnosis has been made, appropriate treatment can begin. Many people assume that surgery is the only treatment for disc injuries, but the fact is that very few of these injuries actually require surgery. The vast majority of disc injuries will resolve or improve with conservative treatment. Conservative chiropractic care includes: flexion distraction to restore mobility and reduce inflammation, ice to reduce pain and inflammation, electrical therapy to decrease pain, spinal adjustments to restore joint mobility, reduce inflammation and decrease muscle spasm, exercise instruction to improve flexibility and strength, advice on posture and movement to prevent aggravation of the injury, and acupuncture can also help to decrease pain and inflammation of the pinched nerve. In those rare cases where patients experience progressive weakness or loss of bowel or bladder control, neurosurgical referral is appropriate.
Disc injuries are a common cause of neck, lower back, arm and leg pain in adults. Fortunately, these injuries usually resolve without the need for surgery. The key is proper diagnosis and specialized Cox Technique chiropractic care provided by Dr. Hazen, along with specific exercise and activity modification.