ABSTRACT
Although needle gauge, type (short or long bevel), and bevel configuration may influence the degree of nerve injury after peripheral nerve block, the findings are conflicting and there are no confirmatory human studies. Theoretically, localization of neural structures with a nerve stimulator would allow a high success rate without increasing the risk of neurologic complications, but this supposition has not been established. Indeed, serious neurologic injury has been reported after uneventful brachial plexus block with a nerve stimulator technique. Likewise, prolonged exposure or high dose or high concentrations of local anesthetic solutions also may result in permanent neurologic deficits. In laboratory models, the addition of epinephrine increases the neurotoxicity of local anesthetic solutions and also decreases nerve blood flow. However, the clinical relevance of these findings in humans remains unclear. Finally, nerve damage caused by traumatic needle placement, local anesthetic neurotoxicity, and neural ischemia during the performance of a regional anesthetic procedure may worsen neurologic outcome in the presence of an additional patient factor or surgical injury.
