Continuous peripheral nerve blocks

A continuous peripheral nerve block—also termed “perineural local anesthetic infusion”—involves the percutaneous insertion of a catheter adjacent to a peripheral nerve, followed by local anesthetic administration via the catheter, providing anesthesia/analgesia for a prolonged period of time. The most-common indication for continuous peripheral nerve blocks is analgesia following painful surgical procedures; but, they are also used for inducing a sympathectomy and vasodilation following digit transfer/replantation, a vascular accident, limb salvage, or peripheral embolism; treating intractable hiccups; alleviating the vasospasm of Raynaud’s disease; and treating chronic pain such as phantom limb pain, cancer-induced pain, complex regional pain syndrome, and trigeminal neuralgia. Continuous peripheral nerve blocks may also provide pain control during medical transport, or awaiting surgical correction. The most common catheter insertion techniques include electrical stimulation and ultrasound-guidance. Long-acting local anesthetic is usually the sole infusate, and is optimally delivered with a continuous basal infusion with available patient-controlled bolus doses. Benefits are dependent upon analgesia improvement, and include decreasing pain, supplemental analgesic consumption, opioid-related side effects, sleep disturbances, patient dissatisfaction, time until discharge readiness, and actual hospitalization duration. Additional possible benefits include improvements in ambulation/functioning and an accelerated resumption of passive joint range-of-motion. Most benefits occur during the infusion itself, but a few studies suggest prolonged benefits following catheter removal in some cases. Minor complications occur at approximately the incidence as for single-injection peripheral nerve blocks; but, major risks including nerve injury are extraordinary uncommon.