Although rarely recognized, the piriformis syndrome appears to be a common cause of buttock pain with radiating to the leg. This seems fully justified by the great potential for confusing this entity with discogenic disease and consequently having unnecessary surgical procedures carried out. This paper is a prospective study of 20 patients, from some 150 patients admitted due to low back and leg pain, with sustained buttock pain with radiating to the leg due to piriformis syndrome after conservative treatment. The ratio females to males is 7 to 3. Trauma history is elicited in 65% of the cases.

Various investigations, including pelvic MRI study, bone scan, electromyography, H-reflex study and sacroiliac joint roentgenography, are of limited diagnostic value. The diagnosis can be made from reproduction of referred pain upon palpation by rectal route and confirmed from dramatic and immediate relief of pain by injection into the piriformis muscle with local anesthetics. 75% of the cases markedly improved immediately after local injection, 80% of the above mentioned remained improved for 2 months.

In conclusion, because of the similarity of symptoms to those of discogenic pain syndrome, patients with the piriformis syndrome can be easily misdiagnosed. We feel that digital palpation of the piriformis muscle during rectal examination should be a part of routine examination for low back pain with radiating to the leg.