What is it?
The condition is relatively common. Estimates suggest that about 5% of cases of sciatica (irritation of the sciatic nerve causing radiating pain from the back or buttock into the leg, calf and foot) are due to piriformis syndrome. It seems to be more common among women though the reason for this is not known.
Symptoms and signs
The typical patient with piriformis syndrome complains of “sciatica” — that is, sharp, severe, radiating pain from the lower back or buttock down the back of the leg and into the thigh, calf, and foot. Symptoms may seem to be due to hip bursitis or disc herniation (“slipped disc”) but the doctor’s examination helps sort out the true cause because with piriformis syndrome the person also has:
- difficulty sitting or putting weight on the buttock on one side
- muscle spasm of the piriformis muscle
- pain in the piriformis muscle during a rectal exam
- sciatica-type pain when the hip is moved and rotated outward against resistance.
Causes of piriformis syndrome
Recognized causes of piriformis syndrome include:
- Abnormal development or location of the piriformis muscle or sciatic nerve
- Abnormal spine alignment (such as scoliosis)
- Leg-length discrepancy (when the legs are of different lengths)
- Prolonged sitting, especially if carrying a thick wallet in a pocket directly behind the piriformis muscle
- Prior hip surgery
- Unusually vigorous exercise
- Foot problems, including Morton’s neuroma.
In many cases the cause cannot be identified.
The diagnosis is “clinical” meaning that it is based on symptoms and physical examination. There is no specific blood test, biopsy, or imaging test to confirm the diagnosis. For this reason, it is difficult to know for sure that a person has the condition and there is some controversy about how common it is. This is especially true because spine and disc disease can cause similar symptoms and piriformis syndrome can be present along with these other conditions such as hip bursitis.
The duration of piriformis syndrome is variable. Often, it is brief in duration, especially if proper treatment begins soon after symptoms appear.
There is no reliable way to prevent piriformis syndrome. For people who have had this or other back problems, standard recommendations include home exercises and stretching, a heel-lift (if the legs are of different lengths), not carrying a wallet in the back pocket, avoiding prolonged sitting, and getting treatment for other contributing conditions (such as spinal arthritis or foot problems).
While medications, such as pain relievers, muscle relaxants, and anti-inflammatory drugs may be recommended, the mainstay of treatment for piriformis syndrome is physical therapy, exercise, and stretching. Specific treatments may include:
- adjustments in gait
- improved mobility of sacroiliac joints
- stretching to relieve tight piriformis muscles and those surrounding the hip
- strengthening of the hip abductors (muscles that move the hips outward from the body)
- application of heat
With prompt diagnosis and treatment, the prognosis is quite good. However, the condition may become chronic; a poor outcome may be more likely if the diagnosis and treatment are delayed.
The Bottom Line
Piriformis syndrome may be the most common cause of sciatic-type back pain you’ve never heard of; or it may be rare, no one is really sure. If you have persistent, unexplained buttock pain that travels into the leg, stop carrying your wallet in your back pocket, try not to sit so much, and see your doctor. You might have a disc problem or some other common back trouble; but you could have piriformis syndrome and finding out sooner rather than later can make a difference.