From the Guidelines
Diagnosing pyriformis syndrome requires a thorough clinical evaluation, as there is no single definitive test, and should be based on a combination of clinical presentation, physical examination, and diagnostic imaging to rule out other causes of sciatic pain. The diagnosis of pyriformis syndrome is often one of exclusion, after ruling out other potential causes of similar symptoms, such as herniated discs or tumors, which can be detected by diagnostic imaging like MRI 1. The clinical presentation of pyriformis syndrome typically includes buttock pain that worsens with sitting, pain with external hip rotation against resistance, and tenderness on palpation of the pyriformis muscle. Some key diagnostic tests that can help identify pyriformis syndrome include:
- The FAIR test (Flexion, Adduction, and Internal Rotation), which can reproduce the patient's symptoms
- Electromyography and nerve conduction studies, which can sometimes detect sciatic nerve compression
- A diagnostic injection of local anesthetic into the pyriformis muscle, which can provide relief and support the diagnosis It's essential to differentiate pyriformis syndrome from other causes of sciatica, hip pathology, and sacroiliac joint dysfunction through careful physical examination and selective testing, as described in the acr appropriateness criteria® plexopathy: 2021 update 1. Pyriformis syndrome is a type of entrapment neuropathy, which can result from spinal or extraspinal compression, and can be detected by imaging, such as lumbosacral plexus MRI, which can help localize the site of nerve compression 1. In some cases, lumbosacral plexus MRI can detect spinal causes of nerve root compression that may not be detected on a lumbar spine MRI, such as a lateral disc herniation that compresses the distal nerve root lateral to the neural foramen 1. Therefore, a comprehensive diagnostic approach is necessary to accurately diagnose pyriformis syndrome and develop an effective treatment plan.
From the Research
Diagnosis of Piriformis Syndrome
The diagnosis of piriformis syndrome can be challenging, and it is often diagnosed only after excluding other possibilities. Some key indicators of piriformis syndrome include:
- A positive Freiberg sign and local tenderness over the piriformis tendon 2
- Buttock pain, pain aggravated on sitting, external tenderness near the greater sciatic notch, and pain on any maneuver that increases piriformis muscle tension, and limitation of straight leg raising 3
- Enlargement of the piriformis muscle with an anterior displacement of the sciatic nerve on magnetic resonance imaging (MRI) 4
Diagnostic Tests
Several diagnostic tests can be used to diagnose piriformis syndrome, including:
- The Freiberg test 2
- The FAIR test, which involves prolongation of the H-reflex with hip flexion, adduction, and internal rotation 5
- Electrophysiological testing and nerve blocks 6
- MRI or computed tomography (CT) scans to rule out other causes of sciatica 2, 4
Treatment
Treatment for piriformis syndrome can include:
- Local injection of triamcinolone acetonide and lidocaine into the piriformis tendon 2
- Physical therapy to relieve symptoms and reduce disability 5
- Surgery in some cases, although this is typically considered a last resort 5
- Ultrasound-guided injection of local anesthetics, steroids, and botulinum toxin into the piriformis muscle 6