While most back or neck pain is caused by either a muscle or ligament strain, which never requires surgery, some people can herniate a disc which can require spine surgery to relieve the symptoms. In some cases, the presence of a herniated disc can imply that the patient is at risk of degenerative disc disease, meaning that they may experience herniations at other levels as well.
Consequently, those who have a herniated disc at one level in their low back or neck, can sometimes have additional herniated discs appear in the future. For these people, the newest FDA-approved artificial discs available now can be of great benefit.
The role of the healthy disc
A healthy disc acts like a shock absorber in between the bony vertebrae of the spine, enabling the spine to rotate. The disc itself resembles a jelly donut. If the disc is compressed or ruptures (from trauma or the stress of lifting something heavy) the jelly center, called the nucleus pulposus, can break through the wall of the disc.
This disc nucleus can then press on nearby spinal nerves causing radiating pain and numbness. Herniated discs in the low back typically cause radiating pain or numbness or weakness in a leg or foot. Herniated discs in the neck conversely cause radiating pain or numbness or weakness into an arm or hand.
While a person can use watchful waiting for three to six months for radiating pain into a leg or arm, that is not the case when the symptom is numbness or weakness in a leg or arm. This symptom is called “neurological deficit” and signals that the herniated disc is pressing on a nerve root off the spinal cord.
Those with symptoms of numbness or weakness in a foot or hand need to be seen by a spine surgeon within 48 hours. Left untreated these symptoms can become permanent and lifelong. Another emergency symptom that appears less frequently is “cauda equina,” where the person experiences loss of control of bowel or bladder because of a herniated disc in the low back.
If these symptoms are not treated promptly, the nerve root can be permanently damaged by the pressure on the nerve root, much like a car parked in the driveway for several days on a garden hose. Even if the car is moved, the hose may be permanently crimped.
Fixing a herniated disc
When a disc herniates, it’s important to understand that the surgeon cannot repair the disc wall. The surgeon instead removes the part of the disc that is pressing on a nearby nerve root. If the disc has been compressed, the surgeon must restore the disc space between the vertebrae by inserting a spacer between the two vertebrae.
The spacer could be a piece of bone harvested from the patient’s own hip bone, or a sterilized piece of cadaver bone from a bone bank. The process of removing the damaged disc and inserting the bone spacer is called a spinal fusion.
Each year in the U.S., more than 200,000 spinal fusion surgeries are performed to relieve pain or numbness caused by damaged discs in the low back and neck.
While the intent of a spinal fusion is to relieve the symptoms of pain or numbness, the downside of spinal fusion surgery is that it causes two vertebrae to become locked in place. This in turn puts additional stress on discs above and below the affected area, which can