The piriformis muscle goes from the sacrum to the hip joints where it inserts. There is one on each side of the body. It is a small muscle that directly overlaps the sciatic nerve as it exits the pelvis into the leg. In 8% of patients, the muscle actually goes through the nerve or the nerve goes through the muscle.

When the piriformis gets inflamed or swollen, it can irritate the sciatic nerve and cause leg pain that can simulate the pain of a pinched nerve root. Piriformis problems are often associated with sacroiliac dysfunction but also occur on their own.

Sacroiliac surgery may sensitize the piriformis, but this is often temporary and responds well with ultrasound applications and muscle relaxants. Rarely, the piriformis may need injections and sometimes surgery.

Conservative treatment involves physical therapy and injections with a numbing agent and cortisone derivatives to decrease the inflammation. More recently, Botox injections have been used to try to relax the muscle.

The diagnosis is often made by a special nerve study that demonstrates a compression of the sciatic nerve when the leg is placed in a position that tenses the muscle.

The piriformis surgery is relatively easy. We cut the tendon of the muscle at its site of insertion, therefore relaxing it. The closure is with deep dissolvable stitches and skin glue. It requires an extra incision (also about 2.5 to 3 inches long).

The problem with this surgery is that this anatomical area is well innervated and therefore more sensitive to pain than the sacroiliac region. Also, the muscle takes some time realizing that it is no longer attached and often goes in bouts of uncomfortable spasms. Even though this procedure is easier than the sacroiliac surgery, most patients say that it is the most uncomfortable.

Even though the wounds usually heal in a couple of weeks, it may take a lot longer (months) for the piriformis and surrounding tissues to settle down. Piriformis surgery, when done with sacroiliac surgery, often adds to the hospitalization time and slows the recovery. In the long run, however, patients who need this extra surgery often do better.