Treating back and neck pain with spinal traction is a practice that's been around for many years. As with many medical treatments, this method has evolved with technology, but the rationale and the effects remain the same.
The goal of spinal traction is to pull the vertebrae apart from each other. The purpose is generally to create more space for nerves where they exit the spinal column or to relieve pressure on the cartilage disks between the bones or on the small spinal joints themselves. At lower intensities, it can also be used to stretch small spinal muscles. The unproven theory is that if the disks are pulled, they will regain hydration or have an influx of water. This would then make them more shock absorbent. What we do know is how much force of pull is needed to get certain areas of the spine to separate between segments. In the cervical spine (neck) it takes about 20-30 pounds of pull to achieve separation. This is a relatively narrow range because the size and weight of the head does not vary greatly. For lumbar traction the amount of pull needed to begin separation of the vertebrae is half the body weight. This means if you weigh 180 pounds, it will take 90 pounds of pull to begin getting separation of the spinal joints and bones.
Is traction effective? The research is a little mixed. For short-term symptom relief, traction seems to be appropriate for some joint-related back and neck pain, but no better than other means of treatment like stretching or joint manipulation. For pain from a disk- or arthritis-related pinched nerve, traction can be effective for some. For patients with arm pain from a pinched nerve in their neck, there are some limitations. The research indicates that if you have had the pain for less than 60 days, and it has been confirmed with an MRI, the problem can be traced to a disk and you might benefit more from intermittent traction. This means that the pull, at least 20 pounds of force, is on for no more than 1 minute, then off, then on again.
The research is less conclusive for treating low back and leg pain. This is probably because it's very difficult to get enough force on the lumbar spine to pull it because of the challenge in holding onto the upper body and lower body while applying the force. The tendency is for the harness to either be very tight or to slip. Lumbar traction has not been shown to be any better than other treatments available for lumbar pain or sciatica.
This brings us to how traction is done. Traditionally it is classified as either manual or mechanical. Manual traction is performed by another individual, usually your medical or rehabilitation provider. Mechanical traction comes in a wide variety of strategies and devices. We will first discuss the difference between sustained and intermittent traction. Intermittent traction is traction where the force of pull is used on and off. This can be done either manually or mechanically. Sustained traction is when the force of pull is held for an extended period of time, usually no more than 30 minutes. While this can be done manually, it is usually done mechanically since the force of pull can be held steady for a longer duration of time.
On the next page, learn how traction is used in medical treatment and physical therapy.