Integrated Role of Musculoskeletal Ultrasound in Piriformis Syndrome: A Case Series

Piriformis syndrome (PS) is an uncommon entrapment neuropathy in which the sciatic nerve is compressed by the piriformis muscle, producing gluteal and radiating leg pain that closely mimics lumbar disc disease and other causes of sciatica, making accurate diagnosis a persistent clinical challenge. Musculoskeletal (MSK) ultrasound has emerged as a valuable imaging modality in this setting, offering real-time, dynamic assessment of muscle morphology, sciatic nerve architecture, and regional vascularity without the use of ionizing radiation. In this retrospective case series of three patients diagnosed with PS at a tertiary care centre in India over a two-year period, high-resolution MSK ultrasound with dynamic provocative maneuvers was employed to evaluate sciatic nerve behaviour in relation to the piriformis muscle. Dynamic imaging successfully demonstrated nerve compression in all three cases, with measurable changes in nerve caliber at the site of entrapment compared to adjacent unaffected segments, providing objective morphological evidence to support the clinical diagnosis. Following diagnostic confirmation, ultrasound-guided injection therapy was administered with complete positional accuracy; two patients received botulinum toxin A to achieve muscle relaxation and sustained nerve decompression, while one patient received a corticosteroid and local anesthetic combination to address inflammatory pain. All three patients achieved complete symptomatic resolution at four-week follow-up, underscoring the therapeutic efficacy of image-guided intervention when the diagnosis is precise. These cases collectively illustrate that MSK ultrasound, through its capacity for real-time dynamic evaluation and procedural guidance, represents a versatile and indispensable tool in the diagnosis and minimally invasive management of PS within a multidisciplinary clinical framework.