Disc Problems & Sciatica
If you experience pain that travels from your lower back down the back of your leg then you may be experiencing sciatica, especially if the pain extends past the knee. Some cases of sciatic pain are caused by bulging discs in the lower back. But there is growing evidence that the disc may not be the whole problem, even when a disc bulge shows up on and MRI.
Studies have shown that anywhere from 25% to over 50% of MRI's produce a false reading for disc bulge or disc protrusion. Even when the radiology report says that your MRI shows a bulging disc, up to 50% or more of these may be false. Of the cases that are true disc bulges and protrusions a large number of the actual symptoms that the patient experiences are frequently attributable to structures other than the disc such as muscles, nerves, ligaments and facet joints.
Bulging discs in the spine are extremely common. The incidence of significant disc changes on an MRI scan is almost identical to the age of the patient. If you look at a 100 MRI's of 40-year old patients you find that about 40% of them will show some degenerative changes in the discs. These changes are certainly not normal, but they are extremely common.
There are several mechanisms that can lead to disc problems and nerve root symptoms such as pain radiating into an arm or leg.
Chronic Spinal Misalignment (Subluxation)
It's tempting to associate the onset of a disc problem with a recent back strain or injury, but these kinds of singular events rarely cause disc herniation in an otherwise healthy spine. Like cavities and heart disease, disc problems are almost always the result of slow degenerative changes. And they are frequently the result of long standing alignment issues in the spine.
When the spine is ideally aligned the flat end plate surfaces of the vertebrae sit parallel to each other. The discs that between sit these end plates as little pads or shock absorbers are able to carry the stress of gravity and other bumps and jolts that the spine gets subjected to in a balanced way. But when the vertebrae not aligned properly the discs are forced to support stress on the spine in an unbalanced way.
Stenosis
Stenosis is a term that means “narrowing of an opening.” The spinal cord and spinal nerve roots travel from the brain to the body through small openings in the 24 movable bones of the spine. When these openings get too narrow pressure can be caused on the spinal cord or spinal nerves.
Every strain of the ligaments and other soft tissues that support the joints triggers a healing response. However, the repaired tissue is not the same as the original tissue. Instead, the body uses scar tissue to mend the injury. There are several problems with scar tissue. One of the problems is that it is thicker than normal ligament tissue. The thickening of ligaments due to repeated (and untreated) strain on the spine from normal daily living as well as from injuries affects the spinal joints. The enlarged fibrotic ligaments shrink the openings (stenosis) where the spinal cord and spinal nerves travel. They can even become calcified over time. The shrinking space for the spinal cord and spinal nerves can result in radiculopathy when the spinal nerves are affected or myelopathy when the spinal cord itself is affected. This can affect the sensory nerves (pain, numbness), motor nerves (muscle spasm, weakness) and autonomic nerves (organ, gland and circulatory dysfunction).
Many people have chronic low grade radiculopathy and myelopathy with little or no associated back pain. In the lower back the effects often show up as organ dysfunction such as chronic bladder infections, infertility or bowel problems. The patient and their doctor may never have a clue that the organ problem is really the result of an underlying spinal neuropathy (radiculopathy) that can be reduced or even eliminated with the proper chiropractic care.
Medically this kind of condition only gets diagnosed when it becomes so severe that the patient has complete loss of bowel control, bladder control or paralysis of the legs. At this point the patient is scheduled for emergency spinal surgery and this is exactly what has to be done when the condition is this far gone. Most medical doctors have little awareness of the number of chiropractic conditions their patients are suffering from. For example, a recent study even demonstrated significant reduction in high blood pressure when alignment problems in the upper neck are properly corrected by a chiropractor. In spite of this people are still prescribed highly toxic medications without being told there may be an easily corrected cause to their ailment. Medical care is important and sometimes essential. But we don't generally expect a medical doctor to check our teeth. They don't have the expertise in that area. That's the job of the dentist. The medical doctor is also not trained in chiropractic care of the spine. That's the job of the chiropractor.
Axial Spinal Cord Tension
The nerves of the body must travel great lengths from their source in the brain to their many destinations. As the nerves travel their long pathways through hard bony tunnels and soft tissues they must be allowed some degree of sliding in order to avoid being overly stretched and damaged as we move our body about. Even the spinal cord itself must slide up and down inside the canal of the spinal column as our spine twists and bends. If pressure occurs anywhere along the path of the spinal cord, that pressure can limit the excursion of the spinal cord and affect the entire length of the cord. For example, a misalignment in the neck or upper back can create tension that impacts the spinal nerves all the way to the lower back.
This kind of axial tension on the spinal cord is not tolerated well. The body attempts to relieve this tension by shortening the overall length of the spinal column. It does this by tightening the small muscles between the vertebrae and shortening the spinal column like and accordion. This helps to partially relieve the tension on the central nerves of the spinal cord.
The pressure of the continuously contracted vertebral muscles squishes the disc, causing it to bulge and ultimately tearing the inner fibers of the disc which allow it to herniate. This is another reason why regular chiropractic care is so important in helping to prevent this and many other health problems.
Peripheral Nerve Entrapment
Nerves can be entrapped anywhere along their path from the boney canal inside the spinal column, past the small openings between the vertebrae past the disc and facet joints and through the muscles and other soft tissues on their way to their target. If a nerve is traveling through tight muscles (for example, tight shoulder muscles or tight buttock muscles) then the entire nerve can be irritated. This can mimic conditions like sciatica when in fact the source of the problem is in a muscle or other soft tissue and not in the spine. This is often the case in conditions like carpal tunnel syndrome [link] where there are frequently multiple sites of nerve compression between the spine and the wrist. It's also the case with sciatica which is sometimes the result of an overly tight piriformis muscle in the buttocks.
In these cases active release of the involved muscles is the quickest way to resolve the problem. We also want to address the spine because most often there is nerve irritation from the spine that is creating the tight muscle issues. A combination of chiropractic and very specific soft tissue therapy is needed in these cases. To understand how disc problems often develop read about pelvic categories.
Dr. Philip Greenwood, D.C.
Murrieta, California
