Sciatica – Causes and Treatment Methods
Sciatica is a condition involving pain down the sciatic nerve– the largest peripheral nerve in the body. Although sciatica is more common in the older population, it can also affect younger people as well. It is characterized by a sharp, focal pain in the lower buttock, very close to the part of the pelvic bone that we sit on (called the ischial tuberosity). In some cases, it can travel down the back of the thigh, all the way to the back of the calf. Sciatica is usually unilateral (one side only), but can also be bilateral (both buttocks/ legs affected). It may be accompanied by lower back pain; and numbness, tingling and weakness in the lower leg.
The sciatica patient will report intermittent pain in the buttock, and may show labored gait. Sitting for more than a few minutes aggravates the condition, so the patient will favor standing when possible. The condition usually is not so severe that it causes disability (the need to stop working). It is more of a “significant annoyance”; most sciatica patients can still walk about, and even engage in light sports.
There are several, known causes of sciatica:
(1) Disc herniation: when a spinal disc herniates (ruptures or bulges outwards), it does so in the posterior (rear) direction, where the spinal cord and nerve roots reside. This is because a very strong ligament called the anterior longitudinal ligament covers the front part of the spinal column, preventing disc movement in that direction. If the bulge presses against one of the nerve roots that form the sciatic nerve, it can cause radicular pain that travels down the buttock and leg. The L3, L4, L5, S1, S2, and S3 nerve roots branch in pairs from the sides of the lumbar (lower) spine and sacrum (triangular bone at the base of the spine that connects to the flat pelvic bones) and eventually combine to form the sciatic nerve, which starts in the gluteal area and travels down the leg.
(2) Spinal stenosis: older people often suffer from degenerative disc disease (DJD). DJD involves thinning discs, hypertrophic (thickened) ligaments, and spondylosis (bone spurring/ thickening). All three of these things can result in the narrowing of the spinal canal– the space between the vertebral bodies and facet joints and spinous processes. The spinal canal is where the spinal cord and nerve roots reside. As the space narrows, cord material can get compressed or irritated by frequent contact with bone, ligament, or disc. Imagine years of moving your back, causing the cord to rub against hard, bony material. Over time, it can adversely affect nerve function, permanently. Spinal stenosis is usually the cause of the chronic, unrelenting form of sciatica.
(3) Piriformis Syndrome: the piriformis muscle is one of the deep gluteal muscles responsible for hip movement. It is attached to the side of the sacrum on one end, and the greater tuberosity of the same side femur bone (hip). The piriformis muscle turns your hip outwards. The sciatic nerve passes between the piriformis muscle and adjacent muscles as it makes its way down the gluteal region to the thigh. If the piriformis muscle spasms, it can effectively “pinch” the sciatic nerve, causing buttock pain and posterior thigh pain.
(4) Pelvic unleveling: the pelvis is made up of two flat bones (named “ischium”), and the sacrum. The femur heads of the femur bones insert into the ischium bones. Under normal conditions, when standing on a flat surface, the femur heads and tops of the pelvis should be exactly parallel to the surface. If for some reason one side is higher than the other, it can cause a shearing force in the gluteal muscles. This can irritate one or several gluteal muscles, and can affect the sciatic nerve as well. Pelvic unleveling can be the result of a hard fall on one buttock and other trauma to the spine and pelvis; uneven leg lengths (one leg physically shorter than the other); foot problems, knee reconstruction, and fractures or bone diseases that result in loss of bone in the femur or tibia.
Sciatica, depending on the cause, can be very difficult to resolve. In some cases, it resolves on its own with rest.
If the cause is related to a disc herniation, treatment geared towards reducing the disc herniation should be considered. This includes surgery, physical therapy, and non-surgical spinal decompression.
If the cause is related to spinal stenosis, the goal of treatment would be pain alleviation. If the stenosis is multiple-level, surgery may not be an option. For these cases, pain medications, nerve blocks/ cortisone injections, and epidurals may be helpful. Hotpacks, icepacks, and gentle stretching of the gluteals can help as well.
If the cause is due to piriformis syndrome, measures to reduce the piriformis muscle spasm would be appropriate. This includes massage therapy, ice and heat, joint mobilization, chiropractic adjustments, and muscle stim.
If the cause of the sciatica is pelvic unleveling, chiropractic adjustments to restore pelvic alignment could help. If the pelvic unleveling does not correct all the way, then shoe orthotics with a heel lift can help keep the pelvis even when standing; thus reducing the shearing force to the gluteal muscles.
In summary, sciatica, while not a very serious condition can adversely affect quality of life by limiting mobility. Self help measures include gently stretching the gluteal muscles, and applying ice and heat. Wear comfortable shoes, and be careful not to walk on uneven surfaces for extended periods (hill, beach, etc.). If it does not go away on its own, visit a qualified health professional to get a proper diagnosis and treatment.
Dan Perez, DC
San Francisco Chiropractor