Background: Painfully decreased cervical range of motion accompanied by muscle spasm is a common presentation of whiplash injury of the neck. Stiffness of the cervical muscles can be assessed by ultrasound shear wave elastography (SWE), expressed in kilopascals (kPa).
The hypothesis: SWE of the trapezius muscle is an objective measurement suitable for the initial screening and follow-up of patients who report whiplash injury.
Methods and results: A total of 99 patients after whiplash injury were compared to 75 control participants. Mean trapezius stiffness was 82.24 ± 21.11 vs. 57.47 ± 13.82 for whiplash patients and controls, respectively. The cut-off value of SWE of 75.8 kPa showed 77% accuracy in correctly assigning patients to the whiplash or control group. To evaluate whether SWE can be used as a follow-up method of recovery after a whiplash injury, initial and endpoint SWE (after six months, n = 24) was carried out. Patients reporting no recovery showed similar SWE values as completely recovered patients. This finding refutes the second part of our hypothesis.
Conclusions: SWE is a method that can be used for the initial screening of patients with whiplash injury, but we are still searching for an objective measurement that can be used in the follow-up of recovery.
Keywords: elastography; shear wave; stiffness; trapezius; ultrasound; whiplash injury.