INFRARED THERMOGRAPHIC EVALUATION OF SPINAL-CORD ELECTROSTIMULATION IN PATIENTS WITH CHRONIC PAIN AFTER FAILED BACK SURGERY

This study sought to visualize spinal-cord stimulation activity by inf ra-red thermography in humans suffering from chronic lumbosciatic pain . All the patients had previously undergone neurosurgery for a herniat ed intervertebral disc. Temperature changes were evaluated in two defi ned body areas after starting, stopping, maintaining or not starting t he stimulation. In one body area, corresponding to the pain location, the patient experienced stimulation paraesthesia, whereas in the non-p ainful (second) area no stimulation paraesthesia were present. The pat ients were studied on four consecutive days with a randomly chosen sti mulation pattern. Temperature changes in identical and comparable skin areas were measured and statistically analysed. No statistically sign ificant temperature variation was found between the painful and non-pa inful areas. These findings do not confirm the idea that spinal cord s timulation induces vasodilation in the affected pain area when stimula tion is present. Infra-red thermography is not able to differentiate t he stimulated from the non-stimulated areas.