Piriformis syndrome is an uncommon neuromuscular disorder that is caused when the piriformis muscle compresses the sciatic nerve. The piriformis is a flat, thin-like muscle in the buttocks near the top of the hip joint. This muscle stabilizes the hip joint, lifts, and rotates the thigh away from the body, which helps to maintain balance by enabling us to walk and shift our weight from one foot to the other.
We also use this muscle in sports when lifting and moving our legs and hips in every degree. Through the piriformis muscle is a long, thick nerve in the back of the leg called the sciatic nerve. This nerve branches off into smaller nerves that go to the feet. The piriformis muscle can have spasms which cause nerve compression.
Incidence and Prevalence
According to a recent study, the prevalence of piriformis syndrome is 17% among patients with low back pain. All patients diagnosed with the condition responded well to muscle injections in the study. Piriformis syndrome is often overlooked among patients with low back pain. The modified FAIR test is a reliable method for diagnosing the condition, especially when combined with the injection.
Causes and Symptoms
With piriformis syndromes, patients describe acute tenderness in the buttock and sciatica-like pain down the back of the thigh, calf, and foot. Typical piriformis syndrome symptoms may include:
Symptoms of piriformis syndrome often become worse after prolonged sitting, walking, or running, and may feel better after lying down on the back. Risk factors for developing piriformis syndrome include being female, prolonged sitting, direct trauma, anatomical variation, and overuse seen with various athletic activities.
Diagnosis and Treatment
Diagnosis of piriformis syndrome is made by the patients report of symptoms and with physical examination by using a variety of movements to provoke pain to the piriformis muscle. There is no diagnostic medical test for piriformis syndrome. In some cases, a tender or contracted piriformis muscle can be found during the physical exam. Symptoms may be similar in some conditions so radiologic test, such as x-rays or MRIs, may be used to rule out other causes of sciatic nerve compression like a herniated disc.
Avoid strenuous activities that may exacerbate the pain, and avoid prolonged sitting, especially against a pressure area such as a wallet. Ice and rest may be helpful. Other treatments for piriformis syndrome include:
Med KC, Nizar AJ (2013). Prevalence of piriformis syndrome in chronic low back pain patients. Pain Practice, 13.