Objectives
To make a quantitative assessment, using infrared thermography (IRT) of the vasodilation process induced by different analgesic currents, and to assess the differences between them. It will also be determined whether the vasodilation is due to the Joule effect or whether there are other mechanisms.
Materials and methods
The study included 12 subjects (6 men and 6 women), with an age range of 23-47 years (mean 34 years and 4 months) and who were assessed by infrared thermography prior to the normal treatment. An assessment with infrared thermography of the spinal column was performed on all of them, at the beginning, after treatment and at 30 and 60 minutes after the treatment was finished. The currents assessed were, biphasic, interferential, ultra-excitatory and diadynamic.
Results
After finishing the treatment an area of hyperaemia appeared beneath the electrodes using a temperature gradient of 3.7¡ãC ¡À 0.82¡ãC (P<0.001) from the baseline. Negligible hyperaemia was observed in the interpolar zones with temperature gradient of 0.9¡ãC ¡À 0.2¡ãC (P<0.05). At 30 and 60 minutes, the local hyperaemia disappeared, being extended across the back and with a temperature gradient at one hour of 1.3¡ãC ¡À 0.03¡ãC (P<0.05).
Conclusions
Analgesic currents produce vasodilation in the polar areas (higher in the cathode in single-phase currents) that gradually decreases and extends throughout the interpolar area. There are no significant differences between the currents at one hour. There may be other vasodilatory mechanisms as well as the Joule effect.
