Treatment of chronic pain with chemical neurolysis

Neurolysis is almost exclusively reserved for the treatment of intractable cancer pain. Rarely, some forms ofnonmalignant pain can be treated with these neurolytic agents (for example, intractable postherpetic neuralgiaand chronic pancreatitis). Neurolysis using cryoanalgesia or radiofrequency is more precise and reversible;thus these agents are often used for chronic nonmalignant pain conditions.Several requisites must be met before neurolysis is performed. In most cases, successful pain relief should bedemonstrated with temporary blockade. The painful area must be sufficiently limited to be served by a readilyaccessible nerve or plexus. A thorough knowledge of the relevant anatomy and the mechanism by which theagent destroys nerve tissue are essential. Neurolysis should be regarded as an irreversible and potentiallypermanent procedure to be considered only when other treatment modalities have failed.A neurolytic block is the targeted destruction of a nerve or nerve plexus. Frequently, the term neuroablation isused to also describe the physical interruption of pain either chemically, thermally, or surgically. All neurolytictechniques cause Wallerian degeneration of the nerve axon distal to the lesion.Chemicals were extensivelyutilized in the past for neurolysis in the early ۲۰ century. The first report of chemical neurolysis was made in۱۸۶۳ by Luton who delivered irritant chemicals subcutaneously in patients with sciatic neuralgia, offering themsignificant alleviation of pain.