SWE in 37-Year-Old Man Awaiting Rotator Cuff Repair for Full-Thickness Supraspinatus Tendon Tear: (A) Patient lies in supine and neutral position, gently stretches neck muscle, and turns head slightly to contralateral side. Transducer is initially placed with application of minimal pressure. (B) Supraspinatus and trapezius muscles identified in transverse plane. (C) Representation of view using sagittal T2-weighted MR image. (D) Transducer turned to longitudinal view. (E) Supraspinatus and trapezius muscles visualized along longitudinal orientation of muscle fibers. (F) Representation of view using coronal T2-weighted MR image. SS = supraspinatus
January 21, 2022 — According to an article in ARRS’ American Journal of Roentgenology (AJR), preoperative shear wave elastography (SWE) can play a complementary role with existing imaging as a prognostic marker for achieving successful rotator cuff repair.
Noting that SWE-derived elasticity is higher in patients with insufficient rotator cuff repair, “elasticity ratio independently predicted insufficient repair,” wrote corresponding author Eun Kyung Khil of Hallym University Dongtan Sacred Heart Hospital in Korea.
From May 2019 to January 2021, Khil’s team prospectively studied 74 patients (37 men, 37 women; mean age, 63.9 years) who underwent rotator cuff repair, including preoperative shoulder MRI and investigational shoulder ultrasound using SWE. The researchers measured mean elasticity of the supraspinatus and trapezius muscles, then calculated the elasticity ratio between the two.
Ultimately, preoperative elasticity ratio of the supraspinatus muscle—determined via SWE—was significantly higher in patients with insufficient rather than sufficient repair (3.66 vs. 1.83) and predicted insufficient repair (odds ratio=15.6) independently of tear size and muscle characteristics assessed by MRI and grayscale ultrasound.
Having measured SWE values in the supine position, rather than in a sitting position, to decrease tone, stiffness, and gravitational load of the trapezius muscle, “future studies are warranted to assess for differences in SWE values between the two positions,” the authors of this AJR article acknowledged.
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