Study design: Interventional feasibility study.
Objectives: To evaluate safety and effects of local heat preconditioning on skin physiology using water-filtered infrared-A radiation (wIRA) or warm water therapy (wWT) in individuals with spinal cord injury (SCI).
Setting: Acute and rehabilitation center, specialized in SCI.
Methods: A convenience sample of 15 individuals (3 women, 12 men) with complete paraplegia from thoracic levels ranging between T2 and T12 received local heat applications either with wIRA or wWT on the thigh (paralyzed area) and on the upper arm (non-paralyzed area). Local heat was applied during three 30-min cycles, each separated by 30 min rest; thus, the treatment lasted for 180 min. Temperature, blood perfusion, and skin redness were measured at baseline, before and after heat application and 24 h after the last application.
Results: Heat applications with wIRA and wWT were well-tolerated. No burns or any other side effects were detected. Skin temperature (p ≤ 0.008) and blood perfusion (p ≤ 0.013) significantly increased after heat application. Local skin temperature (arm p = 0.004/leg p < 0.001) and blood perfusion (arm p = 0.011/leg p = 0.001) after the first and the second application cycle, respectively, were significantly higher during heat application with wIRA than with wWT. However, skin redness did not change significantly (p = 0.1). No significant differences were observed between the paralyzed and non-paralyzed areas for all parameters immediately, as well as 24 h after the treatment.
Conclusions: Although both heating methods have been confirmed as safe treatments in this study, further investigations with regard to their efficacy in the context of preconditioning are warranted.
Sponsorship: The use of the instruments Hydrosun® 750 Irradiator (Hydrosun Medizintechnik, Germany) and Hilotherm-Calido 6 (Hilotherm GmbH, Germany) was sponsored by the Dr. med. h. c. Erwin Braun Foundation and by Hilotherm GmbH, respectively.