Direct Photobiomodulation Therapy on the Sciatic Nerve Significantly Attenuates Acute Nociceptive Sensitivity Without Affecting Motor Output.

Objectives: Pharmacologic pain treatments lack specific targeting and often produce unwanted side effects (eg, addiction, additional hyperalgesia). We previously established that the direct application of laser irradiation (direct photobiomodulation [PBM]) of the sural nerve reduces thermal hypersensitivity in a rodent model of chronic pain, but not mechanical hypersensitivity. These observations were consistent with a selective reduction in the small-diameter fiber contribution to electrophysiologically measured evoked response after direct PBM of a sensory nerve (saphenous).

Photobiomodulation for pain relief: Model-based estimates of effective doses of light at the neural target.

Introduction: Photobiomodulation (PBM) has been studied since the 1960s as a clinical tool. More recently, PBM has been observed to reduce compound action potential components and hypersensitivities associated with neuropathic pains. However, no definitive description of efficacious light parameters has been determined.

Selective neural inhibition via photobiomodulation alleviates behavioral hypersensitivity associated with small sensory fiber activation.

Objective: Photobiomodulation at higher irradiances has great potential as a pain-alleviating method that selectively inhibits small diameter nerve fibers and corresponding sensory experiences, such as nociception and heat sensation. The longevity and magnitude of these effects as a function of laser irradiation parameters at the nerve was explored.

Methods: In a rodent chronic pain model (spared nerve injury-SNI), light was applied directly at the sural nerve with four delivery schemes: two irradiance levels (7.