Direct Electrical Nerve Stimulation
Direct electrical nerve stimulation (DENS), also known as percutaneous electrical nerve stimulation (PENS) and percutaneous neuromodulation therapy (PNT), involves precise ultrasound-guided needle placement adjacent to the nerves involved in the acute or chronic pain syndrome being treated. The procedure includes injecting a low concentration of local anaesthetic to block small diameter (pain transmitting) nerve fibers, while causing minimal disruption to large diameter (sensory and muscle control) nerve fibers, followed by electrical stimulation of large motor fibers for approximately twenty minutes. The electrical stimulation can prolong the pain blocking effect by altering neural activity at the spinal cord level. Electrical stimulation is also conducted by large nerve fibers to stimulate the inhibitory system and suppress the perception of pain in the central nervous system.