Study of ultrasonic scanning techniques and ultrasonographic characteristics of piriformis

Abstract

Objective To explore the scanning techniques of piriformis and different ultrasonographic characteristics of normal and abnormal piriformis. Methods A total of 40 cases diagnosed with unilateral piriformis syndrome underwent ultrasonic examination. Then ultrasonic scanning techniques of piriformis were summarized. Contours, thickness and smoothness of epimysium and ultrasonic echo of internal muscle texture of piriformis were compared between the normal and abnormal piriformis. The study was approved by the Third Affiliated Hospital Ethics Committee of Zhejiang Chinese Medical University (Approval no.ZSLL-JS-2016-18). Results Interruption of ultrasonic echo of ilium could be considered as ultrasonographic signs for locating piriformis quickly and accurately. Abnormal piriformis in suffering side of patients with piriformis syndrome showed obscure contours and being thicker than the other side [χ2=9.899, P=0.002; (25.81±0.30)mm vs (22.29±0.27)mm, t=13.604, P=0.000]. Moreover, there were significant differences in comparing smoothness of epimysium and ultrasonic echo of internal muscle texture of piriformis between the two sides(χ2=23.226, P=0.000; χ2=54.848, P=0.000). Conclusions Interruption of ultrasonic echo of ilium may be an important sign for locating piriformis. Ultrasound can display piriformis clearly and distinguish ultrasonographic images of normal piriformis accurately from abnormal piriformis, which can be taken as an basis imaging for clinical diagnosis of piriformis syndrome. Key words: Ultrasonography; Piriformis