Pyriformis syndrome (part 2) :
Clinical signs of piriformis syndrome relate, either directly or
indirectly, to muscle spasm, resulting nerve compression, or both. Tenderness with palpation over the piriformis muscle, especially over the muscle’s attachment at the greater trochanter, is common. Patients may also experience tenderness with palpation in the region of the sacroiliac joint, greater sciatic notch, and piriformis muscle including pain that may radiate to the knee.
Some patients have a palpable “sausage-shaped” mass in the buttock caused by contraction of the piriformis muscle.A contracted piriformis muscle also causes ipsilateral external hip rotation. When a patient with piriformis syndrome is relaxed in the supine position, the ipsilateral foot is externally rotated a feature referred to as a positive piriformis sign.
Diagnostic Tests
Several clinical tests can be used to aid in the diagnosis of piriformis syndrome. These tests are useful for clarifying clinical situations, though there is no single test specific to piriformis syndrome.
Lasègue, Freiberg, and Pace signs are used in cases of piriformis syndrome. Lasègue sign is localized pain when pressure is applied over the piriformis muscle and its tendon, especially when the hip is flexed at an angle of 90 degrees and the knee is extended. Freiberg sign is pain experienced during passive internal rotation of the hip.Pace sign, revealed with the FAIR (flexion, adduction, and internal rotation) test , involves the recreation of sciatic symptoms. The FAIR test is performed with the patient in a lateral recumbent position, with the affected side up, the hip flexed to an angle of 60 degrees, and the knee flexed to an angle of 60 degrees to 90 degrees. While stabilizing the hip, the examiner internally rotates and adducts the hip by applying downward pressure to the knee. Fishman et al found the FAIR test to have sensitivity and specificity of 0.881 and 0.832, respectively. Alternatively, the FAIR test can be performed with the patient supine or seated, knee and hip flexed, and hip medially rotated, while the patient resists examiner attempts to externally rotate and abduct the hip. The FAIR test result is positive if sciatic symptoms are recreated.
The Beatty test is another diagnostic test for piriformis syndrome. In this test, the patient lies on the unaffected side, lifting and holding the superior knee approximately 4 inches off the examination table. If sciatic symptoms are recreated, the test result is positive.
Neurophysiologic testing can also be used in the diagnosis of piriformis syndrome. Electromyography (EMG) may be beneficial in differentiating piriformis syndrome from intervertebral disc herniation. Interspinal nerve impingement will cause EMG abnormalities of muscles proximal to the piriformis muscle. In patients with piriformis syndrome, EMG results will be normal for muscles proximal to the piriformis muscle and abnormal for muscles distal to it. Electromyography examinations that incorporate active maneuvers, such as the FAIR test, may have greater specificity and sensitivity than other available tests for the diagnosis of piriformis syndrome. Radiographic studies have limited application to the diagnosis of piriformis syndrome. Although magnetic resonance imaging and computed tomography may reveal enlargement of the piriformis muscle
Treatment
Throughout the physical evaluation of patients, clinicians should maintain a high index of suspicion for piriformis syndrome. Early conservative treatment is the most effective treatment, as noted by Fishman et al, who reported that more than 79% of patients with piriformis syndrome had symptom reduction with use of nonsteroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, ice, and rest.
Stretching of the piriformis muscle and strengthening of the abductor and adductor muscles should also be included in patient treatment plans. A manual medicine approach may combine muscle stretches, Gebauer’s spray and stretch technique, and soft tissue, myofascial, muscle energy, and thrust techniques to address all somatic dysfunctions in the patient with piriformis syndrome.If the patient does not respond adequately to manual treatment, then acupuncture and trigger point injection with lidocaine hydrochloride, steroids, or botulinum toxin type A (BTX-A) may be considered.
If all of the pharmacologic and manual medicine treatments fail, the final treatment option is surgical decompression