January 2008

Sciatic Nerve Pain

By Elliot Wagner, O.M.D., L.Ac., Doctor of Oriental Medicine

Because many people see acupuncturists for painful sciatic nerve symptoms, or sciatica, it seems useful to consider this common, disabling, and often misunderstood health problem. In this article, I will discuss what may be emerging as the most common direct cause of sciatica: piriformis syndrome, or pelvic sciatic entrapment syndrome.

The sciatic nerve is the longest and largest nerve in the human body. It runs from the lumbosacral plexus created from the joining of the nerve roots of the spinal nerves at the 4th and 5th lumbar level, with those at the 1st, 2nd, and 3rd sacral level. These join inside the pelvis near the coccyx, then exit the rear of the pelvis through an opening (the sciatic notch) where they emerge into the buttock combined as the sciatic nerve.

From the buttock the sciatic nerve enters the rear of the upper leg, travels the length of the thigh, and divides again above the knee to form two large nerves, the tibial nerve and the fibular (peroneal) nerve, which travel uninterrupted to, respectively, the inside (medial) and outside (lateral) calf, ankle, heel, and sole.

Sciatica is defined as: pain along the course of the sciatic nerve, originating from irritation of or trauma to its fibers above the knee. Sciatic pain can arise in the low back, the buttocks, the rear thigh, the knee, and almost anywhere on the calf, ankles, heels or feet. It usually appears only on one side.

Until recently, sciatica was thought to be caused primarily by irritation of the nerve roots in the spine due to a displaced or ruptured intervertebral disc. However, a study published in the February, 2005 issue of the Journal of Neurosurgery:Spine, opens up for discussion the usual understanding of sciatica as being of discogenic origin. Of the subjects in this study, more than 2/3 were found to have sciatica caused by the painful compression of the sciatic nerve by the piriformis muscle against the wall of the sciatic notch, also known as piriformis syndrome.

For anyone who has suffered from the severe toothache-like pain arising anywhere from the buttocks to the toes that accompanies a diagnosis of sciatica, this news may come as no surprise. After all, a person with sciatica feels as though something is amiss in the buttocks or legs. It also may give hope to those for whom spinal surgery for sciatica has not proved effective. For many of us who treat this condition, it comes as a validation of our experience. For the first time there is conclusive evidence that sciatic pain is caused at least as often by soft tissue pressure on the sciatic nerve as by actual spinal problems. To quote from the study: "One long-standing objection to the validity of piriformis syndrome as a clinical diagnosis has been the unproven assertion that muscle spasm alone cannot produce nerve compression. The results of this study definitively disprove that assertion."

From the standpoint of treatment, it confirms what acupuncturists know: that deactivation of a spasmed piriformis muscle, or of piriformis trigger points, by acupuncture, as well as the use of regular acupuncture as part of a recovery strategy, can help with pain and restoration of function when other approaches have been ineffective.

Patients with piriformis syndrome often do not have the numbness or weakness that accompanies other types of sciatica. They usually have pain as the predominant symptom. Also, there is often tenderness at the greater trochanter, the bony prominence at the side of the hip, and in the mid- buttock. The pain is often made worse with sitting and better with walking. Lastly, piriformis syndrome is more common in women, particularly active women who exercise regularly, including runners.