Neurolytic block

A neurolytic block is a form of nerve block involving the deliberate injury of a nerve by freezing or heating ("neurotomy") or the application of chemicals ("neurolysis").^[1] These interventions cause degeneration of the nerve's fibers and temporary (a few months, usually) interference with the transmission of nerve signals. In these procedures, the thin protective layer around the nerve fiber, the basal lamina, is preserved so that, as a damaged fiber regrows, it travels within its basal lamina tube and connects with the correct loose end, and function may be restored. Surgical cutting of a nerve (neurectomy), severs these basal lamina tubes, and without them to channel the regrowing fibers to their lost connections, over time a painful neuroma or deafferentation pain pain may develop. This is why the neurolytic is usually preferred over the surgical block.^[2]

The neurolytic block is sometimes used to temporarily reduce or eliminate pain part of the body. Targets include^[3]

• the celiac plexus, most commonly for cancer of the gastrointestinal tract up to the transverse colon, and pancreatic cancer, but also for stomach cancer, gall bladder cancer, adrenal mass, common bile duct cancer, chronic pancreatitis and active intermittent porphyria
• the splanchnic nerve, for retroperitoneal pain, and similar conditions to those addressed by the celiac plexus block but, because of its higher rate of complications, used only if the celiac plexus block is not producing adequate relief
• the hypogastric plexus, for cancer affecting the descending colon, sigmoid colon and rectum, as well as cancers of the bladder, prostatic urethra, prostate, seminal vesicles, testicles, uterus, ovary and vaginal fundus
• the ganglion impar, for the perinium, vulva, anus, distal rectum, distal urethra, and distal third of the vagina
• the stellate ganglion, usually for head and neck cancer, or sympathetically mediated arm and hand pain
• the intercostal nerves, which serve the skin of the chest and abdomen
• and a dorsal root ganglion may be treated by targeting the root inside the subarachnoid cavity, most effective for pain in the chest or abdominal wall, but also used for other areas including arm/hand or leg/foot pain.

References

1. Scott Fishman; Jane Ballantyne; James P. Rathmell (January 2010). Bonica's Management of Pain. Lippincott Williams & Wilkins. p. 1458. ISBN 978-0-7817-6827-6. Retrieved 15 August 2013.
2. Williams JE. Nerve blocks: Chemical and physical neurolytic agents. In: Sykes N, Bennett MI & Yuan C-S. Clinical pain management: Cancer pain. 2nd ed. London: Hodder Arnold; 2008. ISBN 978-0-340-94007-5. p. 225–35.
3. Atallah JN. Management of cancer pain. In: Vadivelu N, Urman RD, Hines RL. Essentials of pain management. New York: Springer; 2011. doi:10.1007/978-0-387-87579-8. ISBN 978-0-387-87578-1. p. 597–628.