Piriformis Syndrome is an irritation of the sciatic nerve that occurs in the buttocks. The sciatic nerve is a thick nerve that forms from several spinal nerve roots in the lower spine that travels through the buttocks and extends down to the back of each leg. An irritation of the sciatic nerve in this region can result in pain or numbness and in rare cases weakness in the buttocks and legs.
Anatomy And Cause
As the sciatic nerve comes out of the pelvis to extend to the leg, it travels in underneath a muscle that helps to rotate the hip. This muscle is called the piriformis muscle. Excess tension, muscle trauma, or inflammation either in the muscle or nerve itself may lead to symptoms of sciatica. The actual cause or even existence of this problem in most cases is highly disputed. Many cases appear to have other possible or compounding problems such as lumbar disc herniation, spinal stenosis, hamstring tendonitis, and hip bursitis.
Most cases of supposed Piriformis Syndrome do not show any conclusive evidence of actual nerve compression on MRI images performed of the pelvic and hip. Also EMG nerve tests rarely reveal any abnormality in the sciatic nerve. Rare severe cases, caused by severe trauma to the buttocks will result in more severe sciatic nerve injury that will be evidenced by significant leg weakness and nerve compression findings on EMG nerve tests.
Treatment options include consistent stretching and strengthening of the hip and back muscles. Many cases will respond in part to oral medications: NSAIDs (i.e. Naprosyn, Voltaren) and occasionally anticonvulsants (i.e. Lyrica, Neurontin, Topomax). Injections of the piriformis muscle can be effective in persistent cases. Behavioral modifications such as avoidance of sitting usually should be reversed into a program of gradual sitting exposure.
The surgical release or cutting of a piriformis muscle that theoretically has entrapped the sciatic nerve is highly controversial and rarely performed. There is little evidence that this is effective treatment.