THE EFFECT OF CONTUSION AND CRYOTHERAPY ON SKELETAL-MUSCLE MICROCIRCULATION

Objective, The most common treatment of soft tissue contusions is ice application (cryotherapy). The physiological basis for this therapy is assumed to be cold-mediated vasoconstriction resulting in decreased e dema formation and a reduction in overall morbidity, This proposed mec hanism has not been tested, The present research examined the hypothes is that cryotherapy following contusion is effective because it reduce s microvascular perfusion and subsequent edema formation, Experimental design, The microcirculatory responses to contusion were studied with and without cryotherapy in a chronically instrumented rat model, Init ial studies evaluated the immediate effects of cryotherapy on arteriol ar and venular diameters and microvascular perfusion (using laser Dopp ler fluxmetry). Variables were measured before and immediately after 2 0 minutes of cryotherapy, Two additional studies monitored the same mi crovascular parameters longitudinally in four sets of chronically inst rumented animals, Groups of rats studied had contusion or sham contusi on with ice treatment or no ice treatment, Measurements were performed repeatedly before and after treatment for 24 hours or 96 hours after contusion/sham contusion, Results, The acute microvascular effects of cryotherapy were vasoconstriction and decreased perfusion, However, wh en cryotherapy was used as a treatment following contusion/sham contus ion, there were no long-lasting microvascular effects of cryotherapy e ither in the presence or absence of contusion, Conclusions, These resu lts indicate that cryotherapy of striated muscle following contusion d oes not reduce microvascular diameters or decrease microvascular perfu sion. Alternate mechanisms of action for cryotherapy treatment need to be investigated.