Three-dimensional vibration-controlled transient elastography in human subjects with myofascial trigger pain points

Myofascial pain is associated with chronic lower back pain (LBP) and is a global health problem that affects almost all adults at some point in their lives. The myofascial components of chronic LBP, including trigger pain points (TPP) that are characterized by pain radiating from these points to broader areas, are difficult to diagnose due to a lack of reliable imaging biomarkers. Here, we present preliminary measurements of three-dimensional vibration-controlled ultrasound transient elastography to explore changes in muscle stiffness that accompany myofascial TPP. We scanned 16 subjects with identified myofascial TPP and 16 without any pain points. Elastic waves were excited by applying vibrations to the skin surface using a wide bar driven by a 150-Hz tone burst at four specific locations, including the multifidus and erector spinae muscles, bilaterally at the level of L3 and L4 vertebrae. Propagating waves were captured with the 3-D volumetric image using a row-column array transducer (RCA, Vermon RC6gV, 6 MHz). The propagation speed of the traveling wave was calculated throughout the muscle volume using a time-of-flight approach. Preliminary comparisons suggest that propagation speeds may be higher in lower back muscles with TPP, indicating the potential diagnostic value for myofascial components in chronic LBP.