Feasibility and Reliability of an Ultrasound Examination to Diagnose Piriformis Syndrome

Abstract

We explored the diagnostic performance of ultrasound examinations in the diagnosis of piriformis syndrome (PS). In our single-center retrospective study, 52 patients with a diagnosis of PS and 50 healthy volunteers were enrolled to undergo ultrasound examination of the piriformis and sciatic nerve. The thicknesses of the piriformis and the diameter of the sciatic nerve were measured to compare the differences between the patients with PS and healthy volunteers. The diagnostic performance of ultrasound examinations was assessed by constructing a receiver operating characteristic curve and calculating the area under the curve. In patients with PS, the piriformis and sciatic nerve were enlarged on the abnormal side compared with the asymptomatic side, accompanied by a decreased echo intensity and an unclear perineurium. In addition, the piriformis thickness and sciatic nerve diameter of those with PS were significantly greater than were those of the healthy volunteers. The diagnostic performance of ultrasonography was significant. The area under the receiver operating characteristic curve for piriformis thickness and sciatic nerve diameter to discriminate between the abnormal and asymptomatic sides was 0.778 and 0.871, respectively. Ultrasound examinations can assist in the clinical diagnosis of PS and have the potential to be an alternative method for the diagnosis of PS for most musculoskeletal clinicians.