Reliability of shear wave elastography for cervical and lumbar fascia stiffness and thickness in healthy and chronic neck and low back pain subjects

Purpose: This study had two primary aims: first, to assess the reliability of shear wave elastography (SWE) in measuring the stiffness of the posterior cervical fascia, the posterior layer of the lumbar fascia, and fascia thickness; and second, to compare these fascial properties between healthy individuals and patients with chronic neck and low back pain (LBP). Methods: Thirty participants, including 15 with concurrent neck and LBP and 15 healthy controls, were enrolled. The stiffness and thickness of the fascia, as well as the ratio of fascia stiffness to subcutaneous fat stiffness, were measured in the lumbar and cervical regions. Measurements were performed twice by a single examiner over 1-3 days. Reliability was assessed using the Intraclass Correlation Coefficient (ICC), Standard Error of Measurement (SEM), Minimal Detectable Change (MDC), and Bland-Altman plots. Independent t-tests were conducted to compare group differences. Results: Test-retest reliability for the stiffness of the fascia in the cervical and lumbar regions was excellent, with ICC(3,1) values >= 0.90. Fascia thickness and the ratio showed good to excellent reliability (ICC(3,1) >= 0.80). The SEM, MDC, and limits of agreement supported these findings. Patients with neck and LBP had significantly thicker lumbar fascia than healthy controls (p = 0.002), while no significant differences were found in stiffness between the groups. Conclusion: This study confirms the reliability of SWE in assessing fascia properties. While the lumbar fascia was thicker in patients with neck and low back pain, no significant differences in stiffness were observed between the groups.