Peripheral Nerve Stimulation for Neuropathic Pain

Peripheral nerve stimulation (PNS), the targeted passage of electrical current through the fibers of a localized nerve, is an established and increasingly supported treatment option for neuropathic pain with its rationale based on the gate control theory of pain. PNS is specifically based on the supposition that persistent simultaneous activation of specific large A delta nerve fibers can overwhelm and suppress transmission from the associated small, nociceptive C fibers at the level of the spinal cord and result in a decreased nociceptive signal being relayed to the sensory cortex of the brain. PNS has been applied, with variable levels of success, to an increasing spectrum of pain syndromes including but not limited to trigeminal neuralgia, post-herpetic neuralgia, migraine, occipital neuralgia, chronic back pain, sacroiliac pain, fibromyalgia, postsurgical pain, postamputation pain, and complex regional pain syndrome. The success of PNS is highly dependent on optimal patient selection. Optimal patients are generally those without demonstrated psychological confounders who present with EMG-confirmed neuropathic pain refractory to conservative measures. Pain should localize to a particular nerve root distribution, and at least a 50% reduction in pain severity should be achieved in response to preliminary temporary stimulation testing. Utilization of new technology and refinement of stimulator placement technique, including the advent of percutaneous electrode placement with or without ultrasound guidance as well as the development of increasingly specialized electrode leads and external pulse generators, have allowed for decreased complication rates and more precise stimulation of effected peripheral nerves. Adoption of PNS as a mainstream treatment modality for neuropathic pain is dependent on both continued technologic device advancements and continued conduction of clinical studies with standardized outcomes to generate stronger, empirically supported algorithms for predicting patient-specific responses.