Piriformis Syndrome

What is piriformis syndrome?

Piriformis syndrome is a pain syndrome involving low back or buttock pain that is referred to the leg. It is a controversial syndrome that is an often under-diagnosed cause of sciatica type pain. It is a symptom complex that can involve pain, numbness, and various other presentations. It is estimated to occur in 5%-36% of patients who present with complaints of low back pain. It is a cause of low back pain. that can often be mistaken for or occur in conjunction with other causes of back pain including disc herniation, discitis and bursitis.

What is the piriformis muscle?

The piriformis muscle is a muscle that originates from the anterior or front side of the sacrum bone in the lower back or buttocks. It attaches on the upper part of the femur or thigh bone at site called the greater trochanter. It functions as an external rotator turning the leg outward, a weak abductor pulling the leg to the side and away from the body, and a weak flexor at the hip. It functions to help provide postural stability during standing and walking. The sciatic nerve passes under the piriformis muscle in the majority of people, even piercing or splitting the muscle in as many as ¼ of the population.

How does the piriformis become symptomatic?

The etiology of the pain caused by piriformis syndrome is still somewhat controversial. Most physicians believe the symptoms of piriformis syndrome can be grouped into two different categories; primary piriformis syndrome and secondary piriformis syndrome. Primary piriformis syndrome symptoms are attributed more to an anatomic cause such as a split sciatic nerve, a split piriformis muscle, or another uncharacteristic sciatic nerve path as it passes by the piriformis muscle and exits the pelvis. Secondary piriformis syndrome is caused by traumatic and ischemic events. Only about 15% of cases of piriformis syndrome are a result of a primary cause. The majority are due to macro-trauma to the buttocks causing inflammation and muscle spasm with resulting nerve compression. Micro-trauma causes are usually in the form of overuse injuries such as from walking or running.

Who gets piriformis syndrome?

Piriformis syndrome is a cause of low back pain that can affect a wide variety of patients often dependent on the underlying cause. The overuse syndrome often seems to affect those athletes involved in sports requiring long periods of running. For this reason runners are often victims of piriformis pain syndrome.

What are the symptoms of piriformis syndrome?

The symptoms of piriformis syndrome are many and often somewhat non-specific. The most common of these involves pain after sitting for more than 15 to 20 minutes. The pain usually gets better with ambulation and worse with remaining in one position for a prolonged period of time. The pain usually is from the sacrum or butt bone and radiates into the area of the buttocks and down the back of the thigh to the level of the knee. Sitting cross-legged or rotating the leg inward often will produce pain and patients will often sit or stand with the leg externally rotated.

How is piriformis syndrome diagnosed?

Diagnosis of piriformis syndrome is mostly clinical and requires a high suspicion for the diagnosis as many of the symptoms can be somewhat vague. Patients are often tender over the attachments and length of the muscle especially at the greater trochanter on the thigh bone or femur. Patients will often lay with their foot in an externally rotated position when lying on their backs due to a tight or contracted piriformis muscle. The diagnosis can be aided by the use of several clinical tests. A positive Lasegue sign is seen with pain elicited when pressure is applied over the piriformis muscle with the hip flexed at 90 degrees and the knee straight. A positive Freiberg sign is noted with pain produced when the hip is internally rotated. Electromyography can also be used to help in making the diagnosis and separating it from symptoms caused by vertebral disc herniation. Imaging techniques such as MRI and CT are more useful to rule out other pathologies such as disc herniations or vertebral causes. Helpful information can be obtained from the history of pain and any mechanisms of injury. It is also important to recognize that piriformis syndrome may occur in conjunction with other causes of back pain and sciatica.

What is the typical treatment for piriformis syndrome?

Treatment of piriformis syndrome often is conservative and involves use of nonsteroidal anti-inflammatory medications, muscle relaxers, neuropathic pain medications such as gabapentin or nortriptyline, ice and rest. Piriformis stretching and physical therapy is often the staple of treatment. Stretches usually involve placing the leg in a flexed position at the hip and knee and internally rotated and abducted position at the hip. Therapy often is aimed at strengthening and stretching the hip flexors, adductors, and abductors (see below for videos). Therapists may also attempt Myofascial release techniques. If these conservative measures fail then various injections may be attempted. The use of local anesthetics such as lidocaine, anti-inflammatories such as corticosteroids, or possibly botulinum toxin may be considered. For those cases that fail with the above treatments surgery is a possible option. Recalcitrant cases that have been documented with EMG testing to show neurological impairment have been shown to have the best results with piriformis release surgical procedures.

More Information: Read about sports injury treatment using the P.R.I.C.E. principle - Protection, Rest, Icing, Compression, Elevation.

Be sure to take a look at the following hip strengthening and stretching videos.
Hip Abductor Strength, Test & Exercise.
Quick Hip Strengthening, External Rotators
Stretching Hips/Hipflexors

If you suspect that you have Piriformis syndrome, it is critical to seek the urgent consultation of a local sports injuries doctor for appropriate care. To locate a top doctor or physical therapist in your area, please visit our Find a Sports Medicine Doctor or Physical Therapist Near You section.

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The Piriformis Syndrome. John R. Parziale, MD, Thomas H. Hudgins, MD, and Loren M. Fishman, MD. Am J Orthop. 1997 May; 26(5): 316, 318.

Piriformis Syndrome, Diagnosis and Treatment. Kirschner JS, Foye PM, Cole JL. Muscle Nerve. 2009 Jul: 40(1): 10-8.

Piriformis syndrome and low back pain: a new classification of the literature. Papadopoulos EC, Khan SN. Orthop Clin North Am. 2004 Jan; 35(1): 65-71.

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Vonda Wright

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Vonda Wright, MD
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