Piriformis syndrome

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Piriformis syndrome is a neuromuscular disorder that occurs when the sciatic nerve is compressed or otherwise irritated by the piriformis muscle. This causes pain, tingling and numbness in the buttocks and along the course of the sciatic nerve. The syndrome may result from anatomical variations in the muscle-nerve relationship, or from overuse or strain. Although the existence of this syndrome is disputed by some, two recent uncontrolled studies suppport the possibility (PMID 15739520; PMID 17030664). The need for controlled studies is supported by studies of spinal disk disease that show a high frequency of abnormal disks in asymptomatic patients (PMID 11172169 - see Table 2).

1 Pathophysiology
2 Other presentations
3 Treatment
4 External links
5 See also

[edit] Pathophysiology

In 15% of the population the sciatic nerve passes through the piriformis muscle, rather than underneath it. These people have a far greater incidence of piriformis syndrome than does the general population.

Inactive gluteal muscles also facilitate development of the syndrome. These are important in both hip extension and in aiding the piriformis in external rotation of the femur. A major cause for inactive gluteals is unwanted reciprocal inhibition from overactive hip flexors (psoas major, iliacus, and rectus femorus). This imbalance usually occurs where the hip flexors have been trained to be too short and tight, such as when someone sits with hips flexed, as in sitting, all day at work. This deprives the gluteals of activation, and the synergists to the gluteals (hamstrings, adductor magnus, and piriformis) then have to perform extra roles they were not designed to do. Resulting hypertrophy of the piriformis then produces the typical symptoms.

[edit] Other presentations

In addition to causing gluteal pain that may radiate down the leg, the syndrome may present with pain that is relieved by walking with the foot on the involved side pointing outward. This position externally rotates the hip, lessening the stretch on the piriformis and relieving the pain slightly. Piriformis syndrome is also known as 'wallet sciatica' or 'fat wallet syndrome,' as the condition can be caused or aggravated by sitting with a large wallet in the rear pocket. [1]

[edit] Treatment

Treatment begins with stretching exercises and massage, and the avoidance of contributary activities such as running and bicycling. Some clinicians recommend formal physical therapy, including the teaching of stretching techniques, manual massage, and strengthening of the core muscles (abs, back, etc.) to reduce strain on the piriformis muscle. Anti-inflammatory drugs, Botox, and/or corticosteroid injections can be used. Occasionally surgery may be recommended. The prognosis with treatment is generally good.