Physical Medicine and Rehabilitation for Piriformis Syndrome Treatment & Management

There are several treatment approaches to piriformis syndrome, ranging from nonoperative treatment with physical therapy, costicosteroid injections, and self-stretching to operative management by piriformis muscle surgical release.

Physical Therapy

Because there is no definitive method to accurately diagnose piriformis syndrome, treatment regimens are controversial and have not been subjected to randomized, blind clinical trials. Despite this fact, numerous treatment strategies exist for patients with this condition.

Functional biomechanical deficits associated with piriformis syndrome may include the following:

• Tight piriformis muscle

• Tight hip external rotators and adductors

• Hip abductor weakness

• Lower lumbar spine dysfunction

• Sacroiliac joint hypomobility

Functional adaptations to these deficits include the following:

• Ambulation with the thigh in external rotation

• Functional limb length shortening

• Shortened stride length

Once the diagnosis has been made, these underlying, perpetuating biomechanical factors must be corrected.

Consider the use of ultrasound and other heat modalities prior to physical therapy sessions. Before piriformis stretches are performed, the hip joint capsule should be mobilized anteriorly and posteriorly to allow for more effective stretching. Soft-tissue therapies for the piriformis muscle can be helpful, including longitudinal gliding with passive internal hip rotation, as well as transverse gliding and sustained longitudinal release with the patient lying on his/her side. Addressing sacroiliac joint and low back dysfunction also is important.

A home stretching program should be provided to the patient. These stretches are an essential component of the treatment program. During the acute phase of treatment, stretching every 2-3 hours (while awake) is a key to the success of nonoperative treatment. Prolonged stretching of the piriformis muscle is accomplished in either a supine or an orthostatic position with the involved hip flexed and passively adducted/internally rotated.

Extracorporeal shock wave therapy

Radial extracorporeal shock wave therapy has emerged as a nonoperative treatment option for piriformis syndrome. A randomized, controlled trial by Ahadi et al comparing radial extracorporeal shock wave therapy with corticosteroid injection for the treatment of piriformis syndrome found that pain and quality of life significantly improved in both of the report’s cohorts. However, pain reduction was more rapid in the radial shock wave treatment group, with a decrease in pain noted at 1-week follow-up visit, sooner than in the corticosteroid injection treatment group. Otherwise, there was no significant difference between the cohorts. Radial extracorporeal shock wave therapy is a novel non-invasive treatment of piriformis syndrome, with few adverse side effects. ^[22]

Due to lack of objective clinical trials, no consensus exists on the overall treatment of piriformis syndrome. In most cases, conservative treatment (eg, stretching, manual techniques, injections, activity modifications, natural healing, modalities such as heat and ultrasound) is successful.

Injection therapy

Injection therapy can be incorporated if the situation is refractory to the aforementioned treatment program. For effective injection, the piriformis muscle must be localized manually by digital rectal examination. The piriformis muscle is then injected using a 3.5-inch (8.9-cm) spinal needle. Care must be taken to avoid direct injection of the sciatic nerve. Fluoroscopic or ultrasonographic imaging guidance can significantly enhance the effectiveness of the piriformis muscle injection, because this deep muscle cannot otherwise be directly visualized. ^{[23, 24]}

Failure or partial failure of piriformis syndrome treatment may be secondary to an underlying obturator internus muscle injury, since this problem can be obscured by piriformis syndrome. The obturator internus muscle is inferior to the piriformis muscle and is also an external hip rotator. It originates at the medial surface of the pubis and passes through the lesser sciatic notch to insert on the greater trochanter. Physical examination demonstrates a trigger point that is more caudal than that in piriformis syndrome. Injection therapy would require direct visualization by fluoroscopy, due to the small size and location of this muscle.

Botulinum toxin

A study by Al-Al-Shaikh et al indicated that botulinum toxin (BoNT) alleviates piriformis syndrome by causing atrophy and fatty degeneration of the piriformis muscle. In the study, which involved 20 patients with piriformis syndrome, MRI scans of the piriformis muscle from 12 patients who underwent BoNT treatment were compared with those from eight patients who did not. In the treated patients, the piriformis muscles demonstrated significantly decreased volume and thickness and increased fatty infiltration, with patients experiencing significant pain relief as well, while the untreated patients showed no significant changes in muscle size or thickness. ^[25]

A randomized, double-blind, controlled trial by Fishman et al suggested that piriformis syndrome can effectively be treated with incobotulinumtoxinA chemodenervation. Patients in the study were treated with physical therapy, as well as with either incobotulinumtoxinA or placebo, with the incobotulinumtoxinA group showing greater improvement in the visual analog scale score and in posterior tibial H-reflex delay on the flexion, adduction, and internal rotation (FAIR) test. ^[26]

Surgical management is the treatment of last resort for piriformis syndrome. Surgery for this condition involves resection of the muscle itself or of the muscle tendon near its insertion at the superior aspect of the greater trochanter of the femur (as described by Mizuguchi). ^[6] These procedures may be effective and may not cause associated superimposed postoperative disability. However, because surgical decompression is usually performed later in a chronic state, it may not, even if successful, bring about complete resolution of associated chronic piriformis syndrome pain.

Physiatrists or sports medicine physicians should be the primary consultants for this musculoskeletal condition. Consultation with an orthopedic surgeon for severe or refractory piriformis syndrome is indicated when surgical decompression is being considered.

Prior to physical therapy sessions, the use of ultrasound and the spray-'n-stretch myofascial treatment is helpful. Manual muscle medicine, including facilitated positional release, may also be helpful.

Injections with steroids, local anesthetics, and botulinum toxin type B (12,500 U) have been reported in the literature for the management of piriformis syndrome. ^{[27, 28, 29, 30, 31, 32]} No single technique is universally accepted. Localization techniques include manual localization of the muscle or localization with fluoroscopic, ultrasonographic, and electromyographic guidance. The piriformis muscle, after localization with a digital rectal examination, can be injected with a 3.5-inch (8.9-cm) spinal needle. Care should be taken to avoid direct injection of the sciatic nerve. Randomized comparison of ultrasound-guided imaging versus nerve stimulator with fluoroscopic imaging for piriformis muscle injections shows similar outcomes and without statistically significant differences in imaging or needling technique or total procedure time. ^[33]

In a prospective, double-blind, randomized, controlled trial, Misirlioglu et al found that although local anesthetic injections were effective in piriformis syndrome, the addition of corticosteroid to the local anesthetic did not increase the treatment’s efficacy. ^[34]

Medical acupuncture, including vigorous, direct, deep needling of the piriformis muscle, is performed to reduce piriformis muscle spasm and pain. ^[35]