Piriformis syndrome

Piriformis syndrome is a condition which is believed to result from compression of the sciatic nerve around the piriformis muscle. Symptoms may include pain and numbness in the buttocks and down the leg. Often symptoms are worsened with sitting or running. Causes may include trauma to the gluteal muscle, spasms of the piriformis muscle, anatomical variation, or an overuse injury. Few cases in athletics, however, have been described. Diagnosis is difficult as there is no definitive test. A number of physical exam maneuvers can be supportive. Medical imaging is typically normal. Other conditions that may present similarly include a herniated disc. Treatment may include avoiding activities that cause symptoms, stretching, physiotherapy, and medication such as NSAIDs. Steroid or botulinum toxin injections may be used in those who do not improve. Surgery is not typically recommended. The frequency of the condition is unknown, with different groups arguing it is more or less common. The signs and symptoms include gluteal pain that may radiate down buttock and the leg, and that is made worse in some sitting positions. When the piriformis muscle shortens or spasms due to trauma or overuse, it can compress or strangle the sciatic nerve beneath the muscle. Generally, conditions of this type are referred to as nerve entrapment or as entrapment neuropathies; the particular condition known as piriformis syndrome refers to sciatica symptoms not originating from spinal roots and/or spinal disc compression, but involving the overlying piriformis muscle. In 17% of an assumed normal population the sciatic nerve passes through the piriformis muscle, rather than underneath it; however, in patients undergoing surgery for suspected piriformis syndrome such an anomaly was found only 16.2% of the time leading to doubt about the importance of the anomaly as a factor in piriformis syndrome. Some researchers discount the importance of this relationship in the etiology of the syndrome. Oddly, MRI findings have shown that both hypertrophy (unusual largeness) and atrophy (unusual smallness) of the piriformis muscle correlate with the supposed condition. It has been theorized that people who regularly exercise by running, bicycling, and other forward-moving activities may be more susceptible to developing piriformis syndrome if they do not engage in lateral stretching and strengthening exercises. When not balanced by lateral movement of the legs, repeated forward movements can lead to disproportionately weak hip abductors and tight adductors. Thus, disproportionately weak hip abductors/gluteus medius muscles, combined with very tight adductor muscles, can cause the piriformis muscle to shorten and severely contract. This means the abductors on the outside cannot work properly and strain is put on the piriformis. However, it is also possible that such people are actually experiencing small herniations in a spinal disc which then impinge on the sciatic nerve and cause the piriformis to spasm secondarily. Evidence for a specific relationship between the strength or weakness of certain hip muscles and sciatic nerve pain centered around the piriformis muscle remains scant. Also, this sports-related explanation is useless for understanding piriformis syndrome in those who are not unusually physically active (which is often the case). The result of the piriformis muscle spasm can be impingement of not only the sciatic nerve but also the pudendal nerve. The pudendal nerve controls the muscles of the bowels and bladder. Symptoms of pudendal nerve entrapment include tingling and numbness in the groin and saddle areas, and can lead to urinary and fecal incontinence.