Neuropathic pain refers to pain caused by a lesion or disease of the somatosensory nervous system. Diabetic neuropathy, postherpetic neuralgia, radiculopathy pain, trigeminal neuralgia and complex regional pain syndrome are all neuropathic pain syndromes.

Local administration of botulinum neurotoxin (BoNT)) has proven significant effects on the treatment of neuropathic pain. Abnormal muscle contractions contribute to chronic pain. Botulinum neurotoxin serotype A (BoNT-A) is well known to have an effect on inhibition of muscle contraction and this may partially explain its effect on chronic pain. In preclinical models, BoNT-A was found to effectively block the release of several pain-related neurotransmitters, including norepinephrine, substance P, glutamate and calcitonin gene-related peptide, from afferent nerve terminals and dorsal root ganglia. These pain-related neurotransmitters can stimulate depolarization of C fibers, which are responsible for propagation of chronic pain. BoNT-A also decreases local inflammation around the nerve terminal.

This chapter offers clinical description and pictorial illustration for injection of BoNT for the particular conditions of diabetic neuropathy, postherpetic neuralgia and trigeminal neuralgia.