What are intervertebral discs?
In between each of our spinal bones (vertebra) are discs that act as shock absorbers and keep the vertebrae separated, allowing them to move properly. These intervertebral discs are made up of an inner and an outer layer. The outer layer, the annulus fibrosus, consists of many layers of fibrocartilage, which distribute pressure across the disc. The inner layer, the nucleus pulposus, contains a gel-like fluid with loose fibers floating in it. It is similar to a jelly donut. The annulus fibrosus is the delicious, sweet doughy pastry shell, and the nucleus pulposus is the sticky red jelly that inevitably ends up all over your shirt.
What causes a disc injury (herniation)?
When you bite into the front of that donut, the jelly gets forced to the back of the donut. With a strong enough bite, or repeated small bites, the jelly is forced to the outside of the donut. Taking a big bite out of a donut is analogous to undergoing major trauma to the spine (car crash, sports collision, etc.) Taking many small bites is equivalent to experiencing a series of microtraumas to the spine (the damaging “flexed” position typical of poor posture, the repetitive motions of typing, etc.) The microtraumas accumulate over months to years and can cause the disc to degenerate. Aging, poor nutrition (such as eating too many donuts!), and chronic smoking also factor into determining the extent of disc degeneration. The pain associated with a disc injury comes partially from the mechanical irritation of the “jelly” squeezing it’s way out of the disc and into the epidural space, where it presses on delicate nerve roots. Further pain is caused because the “jelly” contains chemical irritants called cytokines, which cause inflammation and irritation of the nerve structures in the area.
What should I expect?
The pain associated with a disc injury may start slowly, and may get worse after standing or sitting, when bending backwards, or when coughing, sneezing, or laughing. The most common area for a disc injury is the lower back. You may have sharp pain in the leg, hip, or butt. There may also be pain, tingling, or numbness below your knee or into your foot. This is commonly referred to as sciatica. A disc injury in your neck may result in pain upon moving the neck, pain in your shoulder, arm, and sometimes into the fingers. Some disc injuries also result in muscle weakness in the involved areas. Your symptoms will likely resolve in weeks to months. Most cases resolve without surgery, but there are instances when a patient elects to have surgery so that they can get out of pain faster. You will need to notify your doctor immediately if you notice progressive muscle weakness, numbness or tingling in your genital or anal area, or loss of bowel or bladder function.
What to do about it?
To allow a disc injury to heal, we need to remove the damaging stimulus. This may mean avoiding certain postures, lifting lighter loads, and bracing your core before making sudden movements. As soon as you are able, you should return to your normal activities unless they aggravate your pain. Avoid sitting for long periods of time without taking a break, bending, and twisting. As soon as you injure a disc, apply ice to the painful area for twenty minutes every two hours. After three days, you can start to use a heat pack for twenty minutes every two hours to reduce muscle spasms and increase circulation. Therapies such as ART, Garston, and chiropractic manipulation can be useful to address soft tissue restrictions in the damaged tissues. Depending on the individual and the extent of the injury, your doctor can come up with the most appropriate treatment plan for you. Once the healing process is underway, these manual therapies can be combined with exercises to further rehabilitate your injury. These exercises are designed to strengthen the muscles in the injured area, as well as balance out different muscle groups so that the spine will be under minimal stress.