THE EFFECT OF TOPICAL HEAT TREATMENT ON TRAPEZIUS MUSCLE BLOOD FLOW USING POWER DOPPLER ULTRASOUND

PURPOSE: To evaluate the effect of topical heat treatment on trapezius muscle vascularity (blood volume) using power Doppler ultrasound. METHODS AND MATERIALS: A temperature-controlled heating pad (Lauda Clear-view, model MD12-BDLCM, Brinkman Instruments, Inc.) was used to heat the upper back region (mid-trapezius muscles) of six healthy volunteers. The three heating pad-skin interface temperatures tested were 38 [degrees] C, 40 [degrees] C, and 42 [degrees] C. The trapezius was chosen over other large muscles because its broad flat shape makes ultrasound sampling easy. In addition, its size, location, and proximity to the overlying skin makes it ideal for assessing vascularity using ultrasound. The changes in vascularity were measured at 18 sites in the trapezius muscles (from just below the skin surface to a depth of approximately 3 cm depending on the thickness of the muscle) pre- and 30 minutes post-heat treatment at each visit using power Doppler ultrasound (GE Logiq 700 ultrasound scanner). ANALYSES: Analysis was performed using a modification of the program Matlab (The Mathworks, Natick, MA). A log transformation was applied to normalize the data. Mean percent change from baseline scores were calculated by subject and treatment period and analyzed using an analysis of variance for a three period crossover design. One-tailed t-tests were used to test for percent increases in vascularity from baseline. The different temperature groups were also compared using t-tests. RESULTS: Vascularity of the trapezius muscles increased 27% (p=0.250), 77% (p=0.036), and 104% (p=0.011) with heating pad-skin interface treatment temperatures of 38 [degrees] C, 40 [degrees] C, and 42 [degrees] C respectively 'when compared to pre-treatment baseline measurements. CONCLUSIONS: This preliminary study indicates that topical heat treatment for 30 minutes increases the amount of vascularity in the underlying trapezius muscle up to approximately three centimeters below the surface of the skin. This increased vascularity is likely the result of increased muscle tissue blood flow and may contribute to the analgesic and muscle relaxation effects of topical heat therapy.
Erasala GN(*), Rubin JM, Tuthill TA, Fowlkes JB, de Dreu SE, Hengehold DA(*), Weingand KW(*). Department of Radiology, University of Michigan, Ann Arbor, MI, USA and (*) The Procter & [...]