The piriformis originates from the anterior aspect of sacral vertebrae 2 through 4 and inserts on the greater trochanter. The sciatic nerve typically exits the greater sciatic notch just below the inferior border of the piriformis muscle. In about 7% to 21% of studied populations, the sciatic nerve (or a division of it), actually penetrates the muscle. 3,12,15,30,32,33

Edwards14 defines piriformis syndrome as neuritis of branches of the sciatic nerve caused by pressure of an injured or irritated piriformis muscle. Symptoms associated with piriformis syndrome typically consist of buttock pain that radiates into the hip, posterior aspect of the thigh, and the proximal portion of the lower leg.28,29 In general, pain increases with sitting or squatting, but persons with piriformis syndrome may experience difficulty with walking or other functional activities.12,29 Piriformis syndrome typically does not result in neurological deficits such as decreased deep tendon reflexes and myotomal weakness.29

Several authors attribute piriformis syndrome to a shortening or “spasm” of the piriformis that results in compression of the sciatic nerve.6,10,15,27,29,33 The cause of spasm of the piriformis muscle has been most attributed to direct trauma, postsurgical injury, lumbar and sacroiliac joint pathologies, and overuse.151617,27,29 Given as such, the standard treatment for piriformis syndrome has focused on decreasing spasm or shortening of the piriformis muscle and any associated inflammation. Medical management of piriformis syndrome is reported in the literature to include injections, 1,3,5,8,11,15,16,26,27,30 prescription of nonsteroidal anti-inflammatory drugs and muscle relaxants, 1,5,8,11,15,16,26,27 surgical release, 1,5,8,11,14,16 and referral to physical therapy.1,5,11,15,20,27,30 The most commonly reported physical therapy interventions include ultrasound, 1,5,11,16,19 soft tissue mobilization, 1,5,11,15,16,19,30 piriformis stretching, 1,11,15,16,19,26,27,30 hot packs or cold spray, 5,11,15,16,19 and various lumbar spine treatments.1,5,8,10,13,26,30

As noted above, a common assumption guiding physical therapy intervention for piriformis syndrome is that the piriformis is shortened or in spasm, creating compression of the sciatic nerve. Our alternate theory is that the piriformis muscle maybe functioning in an elongated position or subjected to high eccentric loads during functional activities secondary to weak agonist muscles. For example, if the hip excessively adducts and internally rotates during weight-bearing tasks due to weakness of the gluteus maximus and/or gluteus medius, a greater eccentric load may be shifted to the piriformis muscle. Perpetual loading of the piriformis muscle through overlengthening and eccentric demand may result in sciatic nerve compression or irritation.

Interestingly, many authors have recognized hip abductor weakness as an associated finding with piriformis syndrome.1,2,3,5,8,13,17,27,32 Yet only 2 of these reports included hip abduction strengthening as part of the treatment program, 1,17 with 1 of the 2 authors noting that hip abduction exercises “seemed to hasten recovery.”17 Therefore, a treatment program addressing hip strength and movement reeducation to control the femur in the frontal and transverse planes during functional activities may play a role in the treatment of patients with piriformis syndrome who demonstrate excessive frontal and transverse plane motions at the hip.

The purpose of this case report was to describe an alternative treatment approach for piriformis syndrome that emphasizes hip muscle strengthening and movement reeducation. The patient in this case had symptoms consistent with piriformis syndrome, weak hip abductors and external rotators, and excessive hip adduction and internal rotation during functional lower extremity activities.

Case Description

General Demographics The patient was a 30-year-old male who worked as a real estate agent. He also reported that he was a part-time tennis instructor and participated in a weekly basketball league. Apart from his current symptoms, the patient also had a 15-year history of intermittent low back pain.

History of Presenting Condition The patient was initially seen by an orthopaedic surgeon and given a diagnosis of sciatica. At this visit, radiographs were obtained of his lumbar spine and hip, which revealed no abnormalities. The patient was subsequently referred to physical therapy. The patient presented to physical therapy with a 2-year history of deep right buttock pain that radiated to the posterior thigh. The patient stated that the onset of his pain was insidious and denied any trauma that contributed to his current symptoms. The patient did not report any prior treatment for his buttock and thigh pain, but stated that he received intermittent chiropractic treatment for his low back symptoms.

Presenting Complaints The patient reported that his symptoms were exaggerated by playing basketball or tennis for 30 to 60 minutes. Stairs and squatting activities also were noted as aggravating activities. He reported that his pain was alleviated when he stopped participating in sports, but that it would be 4 to 6 days before symptoms would completely resolve. The patient's current activity level included participation in a weekly basketball league and teaching tennis 6 to 12 hours per week. He reported having to modify his tennis instruction to avoid running activities. The patient's symptoms were limiting the number of tennis lessons he could give per week and his ability to play basketball. The patient's stated goals were to participate in his weekly basketball league and return to his normal regime of tennis lessons of 3 nights per week for 2 to 4 hours.

Test and Measures Pain and Functional Status The patient completed a visual analog scale (VAS), where 0 is no pain and 10 is the most pain possible, to assess his current level of pain.34 The patient's baseline pain in his buttock and posterior thigh was 3/10 and reached a level of 9/10 after participation in 1 game of basketball. Prior to treatment, the patient completed the Lower Extremity Functional Scale to evaluate his functional status with regards to his buttock and posterior thigh symptoms. This self-assessment functional tool has been shown to be valid and reliable.4 The patient's score on the Lower Extremity Functional Scale Questionnaire was 65/80, with 80 representing maximum function. Differential Diagnosis Screening Active and passive examination of the lumbar spine and sacroiliac joint were performed to rule out spine and pelvic contributions to his symptoms. Active examination tests for the lumbar spine consisted of active range of motion (AROM), followed by AROM with overpressure in flexion, extension, and sidebending and rotation to the left and right. Passive testing was performed using both central and lateral posterior-to-anterior spring tests from the fifth lumbar to the tenth thoracic spinal segments. There was no reproduction of his buttock or thigh symptoms with active or passive testing to the lumbar spine. The sacroiliac joint was assessed using a cluster of tests, as described by Laslett.21 All tests were negative with respect to the reproduction of symptoms. Hip Joint Examination Passive motion assessment of the hip joint revealed normal ranges for hip flexion, internal rotation, and external rotation without reproduction of symptoms. Hip flexor muscle length was assessed using the Thomas test.18 No restrictions were noted when the 1-joint hip flexor was assessed (ie, iliopsoas); however, restrictions (−12°) were evident when evaluating the 2-joint hip flexor (ie, rectus femoris). Clinical tests were performed to assess for intra-articular hip joint pathology. The scour test, hip quadrant test, log roll test, FABER, and active straight leg test23 were performed, and all were negative with respect to reproduction of the patient's symptoms. Clinical tests also were performed to assess for piriformis syndrome. These tests included the piriformis stretch test above and below 60° of hip flexion, 2,5,15,16 the flexion/adduction/internal rotation (FAIR) test, 5,15,16 and piriformis contraction test.2 The piriformis stretch test below 60° was performed by maximally adducting and internally rotating the hip, with the hip flexed to 45°. The piriformis stretch test above 60° was performed by maximally adducting and externally rotating the hip, with the hip flexed to 90°. The FAIR test was performed by placing the patient in a sidelying position on the unaffected side, with the affected (superior) hip being moved passively into flexion, adduction, and internal rotation.15,16 The piriformis contraction test was performed by placing the patient in the FAIR test position and having the patient elevate the knee off the table for 5 seconds.2 The patient was found to have reproduction of buttock and thigh symptoms with both of the piriformis stretch tests, the FAIR test, and the piriformis contraction test. Neurodynamic testing, as described by Butler, 7 was performed to assess the sciatic nerve. Reproduction of buttock pain occurred at 50° of hip flexion during the straight leg raise test. Assessment of the straight leg raise test with ankle dorsiflexion resulted in reproduction of lower back, buttock, and posterior thigh pain, with only 10° of hip flexion. Symptoms resolved with ankle plantar flexion. Soft tissue palpation revealed tenderness of the piriformis muscle and trochanteric bursa. Palpation also resulted in the reproduction of buttock and posterior thigh pain. Muscle Strength Manual muscle testing of the hip musculature was performed as described by Kendall et al.18 Hip extensor strength was tested in the modified position, due to hip flexor tightness. Manual muscle test grades of 3+/5, 3+/5, and 4−/5 were given for the hip extensors, hip abductors, and external rotators, respectively. Dynamic Assessment An observational gait analysis was performed as the patient walked at a self-selected pace. The patient demonstrated decreased hip extension bilaterally in terminal stance. He also demonstrated abnormal movements in both the frontal and transverse planes during the stance phase on the right: (a) right trunk lean during single-limb support, (b) increased hip adduction during loading response through terminal stance, (c) increased hip internal rotation during weight acceptance through terminal stance, and (d) contralateral pelvic drop during single-limb support. The patient also was evaluated while performing a step-down maneuver, as described by Souza and Powers.31 The step-down task was selected because it is a single-limb activity, thereby placing greater demands on the lower-extremity musculature. The step-down test involved the patient stepping down slowly from a 20.4-cm step using the affected limb over a 2-second period. During this test, the patient demonstrated a contralateral pelvic drop, increased hip adduction, and increased hip internal rotation (FIGURE 1A). The patient also reported an increase in symptoms during this test (7/10 on the VAS). The patient was then provided verbal and visual instructions in an attempt to correct the excessive hip adduction and internal rotation during the step-down test. A repeated assessment of the step-down test was then performed without significant change in hip motion or symptoms. A hip-strapping device (SERF Strap; DonJoy Orthopedics Inc, Vista, CA) was then applied to the patient to assist with hip control while performing this maneuver. The SERF Strap consists of a thin elastic material that is secured to the proximal aspect of the leg, wraps in a spiral fashion around the thigh, and is anchored around the pelvis (FIGURE 2). The line of action of the SERF Strap pulls the hip into external rotation, with the intent of limiting excessive hip adduction and internal rotation during functional activities. The patient was observed to have decreased hip adduction and internal rotation, and reported decreased pain (4/10) when repeating the step-down test with the SERF Strap. We believe that the decrease in pain, combined with improved hip kinematics, could be interpreted as a diagnostic indicator that abnormal movement patterns at the hip were a contributing factor to his symptoms. Download Figure Download PowerPoint FIGURE 1. Patient performing the step-down maneuver pretreatment (A) and posttreatment (B). Both photos were taken at the same knee flexion angle (as assessed by motion analysis). Pretreatment, the patient demonstrates a greater amount of hip internal rotation and adduction and contralateral hip drop. Download Figure Download PowerPoint FIGURE 2. The SERF Strap consist of a thin, elastic material that is secured to the proximal aspect of the leg, wraps in a spiral fashion around the thigh, and is anchored around the pelvis. The line of action of the SERF Strap pulls the hip into external rotation.

Biomechanical Evaluation In addition to the clinical information obtained during the physical examination, the subject underwent a preintervention and postintervention biomechanical evaluation at the Musculoskeletal Biomechanics Research Laboratory at the University of Southern California. The purpose of this testing was to provide objective data to compare the subject's lower extremity kinematics before and after the intervention. Three-dimensional motion analysis was performed using a computer-aided video motion analysis system (Vicon, Oxford, UK). Kinematic data were sampled at 120 Hz. Reflective markers (14-mm spheres) placed on specific anatomical landmarks were used to determine lower extremity joint motions in the sagittal, frontal, and transverse planes. Data were obtained while the patient performed the step-down maneuver. The subject was instructed to stand on his right lower extremity while performing a step-down in 2 seconds and to return to the starting position in 2 seconds. The depth of the step for the step-down maneuver was set at 18 cm (approximately 10% of the patient's total body height). The speed of the movement was guided with a metronome set at 60 beats per minute. When averaged across 5 repetitions, peak hip adduction and internal rotation were 15.9° and 12.8°, respectively (FIGURE 3). These values were considered excessive, based on the normative data previously published by Souza and Powers.31 Download Figure Download PowerPoint FIGURE 3. Comparison of (A) hip adduction and (B) hip internal rotation during the step-down maneuver pretreatment and posttreatment.

Assessment Given the subjective and objective information obtained during our examination, it was our impression that the patient demonstrated significant impairments specific to the hip region. More specifically, our patient presented with weakness of the hip extensors, abductors, and external rotators, limited control of the hip and pelvis during functional movement testing, and reproduction of symptoms with passive stretching and activation of the piriformis muscle. We theorized that weakness of the gluteus maximus and gluteus medius was contributing to abnormal movement patterns at the hip, thereby subjecting the piriformis to excessive lengthening or eccentric loading during functional activities. In turn, we believed that the excessive lengthening of the piriformis was compressing the sciatic nerve. The fact that the application of the SERF Strap resulted in a simultaneous improvement in hip motion and buttock pain supported our hypothesis. Therefore, it was our belief that an intervention focused on addressing the hip muscle weakness and abnormal movement patterns would alleviate the patient's pain and improve his functional status.