What is piriformis syndrome?
Piriformis syndrome is a rare condition in which the muscle pinches off the sciatic nerve. The piriformis is a big muscle in the buttocks that attaches at the hip. Compression of the nerve causes pain sensations to travel through the buttocks to the back of the leg, often with tingling or numbness. This type of pain is called sciatica. Usually sciatica is not the result of piriformis compression, but rather a herniated spinal disc.
What causes piriformis syndrome?
Repetitive motions performed during activities such as running or lunging stress the piriformis muscle causing contractions that apply pressure to the sciatic nerve. Prolonged sitting, climbing stairs, squatting, or running uphill can also irritate the piriformis. Compression of the sciatic nerve results in inflammation that exacerbates pain, leading to a chronic condition. Physical trauma to the area may lead to fibrosis in the muscle that puts pressure on the sciatic nerve.
Other conditions that may result in piriformis syndrome include:
- Cerebral palsy
- Total hip arthroplasty
- Pseudoaneurysm in the inferior gluteal artery near the sciatic nerve
A definitive test for piriformis does not exist, so a diagnosis is determined based on a detailed history and physical exam.
Assessment and history of pain
The physician asks questions to find out when the pain began, how long the pain lasts, and what aggravates the pain. The patient describes the character of the pain, which is often characterized as a dull ache in the center of the affected buttocks.
Patients report pain that radiates down the back of the leg that is made worse by sitting or walking up stairs or along an incline. Piriformis syndrome may also present with weakness, numbness, or tingling in the lower extremities.
Tests and maneuvers
By palpating the piriformis, the doctor may determine if it is contracted and tense.
The Freiberg test determines involvement of the piriformis muscles when forced internal rotation of the extended thigh results in pain. Another movement that contracts the piriformis muscle selectively is the Beatty maneuver. Assuming a side-lying position, bending the knee towards the chest, and then abducting the thigh activates the piriformis and results in pain. A physical exam may show shortening of the leg length on the affected side and the patient may also present with a splayed foot on the affected side when lying on their back.
An X-ray or MRI scan may be performed to rule out other problems with the surrounding tissues. It’s important to rule out other, more common causes of sciatica, such as:
- Herniated spinal disc
- Fibrous adhesions of other muscles in the area surrounding the sciatic nerve
- Hamstring tendinitis
- Nerve conduction tests may be helpful in excluding other conditions
Piriformis syndrome is marked by muscle tension and spasms that affect the sciatic nerve that passes through the buttocks down the back of the leg, terminating in the smaller nerves at the feet. Most patients report an ache deep in the buttocks, which is intensified by sitting or climbing stairs. Piriformis can be an acute condition that resolves with rest, or a chronic, debilitating problem resistant to treatment.
Ice, heat, stretching
Ice packs applied to the area for 20 minutes every two to four hours are recommended initially for an acute injury. Pain management after the first 24 hours utilizes heat. A heating pad placed on the muscle for 20 minutes at a time may reduce inflammation and pain. The patient may receive a physical therapy consult to learn stretching exercises that relax the piriformis muscle and reduce pressure on the sciatic nerve. These stretches involve moves that flex and adduct the hip.
Massage speeds up the heating process by increasing blood flow to the inflamed area and stopping muscle spasms. The physician may prescribe muscle relaxers or anti-inflammatory medications. A holistic treatment plan can incorporate acupuncture to decrease tension in the body.
If pain persists after trying all the interventions mentioned above, the physician may recommend a corticosteroid and anesthetic injection to the area to reduce inflammation and pain. Iontophoresis is a therapy that uses a mild electric current to deliver medication to the muscle through the skin. For this procedure, the electrode containing a medication solution (steroid or other) is placed on the skin and a low voltage current is employed to drive the ions through the skin into the muscle.
Another treatment option is the injection of BOTOX® to weaken the piriformis muscle. Botox inhibits nerve signals traveling to the muscle, causing tonal relaxation and inhibiting the involuntary muscle contractions. The effects of Botox are temporary, but interrupting the cycle of muscle tension and nerve inflammation may allow the patient time to rest and recover from piriformis syndrome.
Surgery is an extreme measure only taken as a last resort in treating chronic, debilitating pain.