C-fiber-Selective Peripheral Nerve Blockade

Despite the clinical demand, current uses of local anesthetics do not allow selective blockade of nociceptive fibers. Regional anesthesia produces an analgesic effect accompanied with undesired side effects due to block of motor, non-nociceptive sensory and autonomic fibers. These side effects limit the clinical use of local anesthetics and affect the recovery and rehabilitation period after surgical procedures. Therefore one main goal of research in the field of regional anesthesia is selectively targeting nociceptive fibers. Recent studies describing the role of nociceptive specific sodium channels in generation and propagation of nociceptive signals make these channels ideal targets for pain selective blockade. In addition, novel methods of targeted delivery of charged local anesthetics selectively into nociceptors provide another potentially successful approach for c-fiber specific nerve block. This review summarizes currently on-going studies on several promising targets and methods to achieve pain selective anesthesia.