Use of low level laser therapy to control neuropathic pain: A systematic review.

Neuropathic pain can be defined as pain initiated or caused by a primary lesion or dysfunction in the central or peripheral nervous system. The low level laser therapy (LLLT) has gained great prominence as a treatment in this type of pain; however, the application parameters are still controversial in the literature. This study aimed to review the literature on the use of LLLT in neuropathic pain with the goal of establishing a "therapeutic window" for the effective use of this treatment. We analyzed 14 articles, 10 in experimental animals and 4 in humans. The results are presented in three tables, the first being for comparison of the studies' application parameters, the second showing the average and median parameters experimental studies and third showing the clinical studies embodiment. The experimental studies revealed better results for LLLT and infrared laser powers above 70mW. Clinical studies are inconclusive as to the application parameters, due to the discrepancy; however all demonstrate the effectiveness of LLLT. According to the data presented, it was concluded that LLLT has positive effects on the control of analgesia for neuropathic pain, but further studies with high scientific rigor are needed in order to define treatment protocols that optimize the action LLLT in neuropathic pain.