create a light pink appearance within the affected area. Lumbar sympathetic neurolysis alters the ischemic rest pain transmission by changing norepinephrine and catecholamine levels or by disturbing afferent fibers. This procedure is mainly used only when other feasible approaches to pain management are unable to be used. Lumbar sympathetic neurolysis is performed by using absolute alcohol, but other chemicals such as phenol, or other techniques such as radiofrequency or laser ablation have been studied. To aid in the procedure, fluoroscopy or CT guidance is used. Fluoroscopic guidance is the most frequent, giving better real-time monitoring of the needle. The general technique of administering lumbar sympathetic neurolysis involves using three separate needles rather than one because it allows for better longitudinal spread of the chemicals. Complications can arise from this procedure such as nerve root injury, bleeding, paralysis, and more. Complications have been seen to be diminished when using the aforementioned radiofrequency or laser ablation techniques in comparison to the injection of alcohol or phenol. Generally, approximately two-thirds of patients can expect a favorable outcome (pain relief with minimal complications). Overall, the minimally invasive technique of lumbar sympathetic neurolysis is important in the relief of ischemic rest pain. Chemodenervation Chemodenervation is a process used to manage focal muscle overactivity through the use of either phenol, alcohol, or one of the more recently discovered botulinum toxins (BoNTs). Chemodenervation is used as a complement to neurolysis. The agent of choice is injected into the muscle fibers as opposed to nerve tissue and the two work together to dull the neuronal signaling within the muscles. The effects of alcohol and phenol injections are different from the effects of BoNTs. Neurolysis mediates the effects of alcohol and phenol injections but does not mediate the effects of BoNT injections. Phenol and alcohol are less expensive, faster acting, can treat larger areas, and can be re-administered or boosted in less than three months, however, those injections also require the patient to be sedated, cause muscle scarring, and can lead to muscle fibrosis. BoNT injections are easier to inject, better accepted by patients, and have reversible effects on muscles, however, they are more expensive, act very slowly, and the body can develop a resistance to them. References Materials degradation Nerves Neurosurgery