title: Neurologic complications of regional anesthesia.
abstract: OBJECTIVE
  Regional anesthesia is evolving rapidly and increasing in popularity as evidenced by the large number of publications on the topic. In this healthcare environment, continual assessment of the safety and efficacy of clinical practice is critical. Neurologic complications of regional anesthesia can result in disability and are feared by patients and clinicians. Ultrasound guidance is unique as a nerve localizing technique in terms of being able to image needle-nerve proximity and potentially prevent direct trauma to nerves. This article reviews the recent literature relevant to neurologic complications of regional anesthesia.
  
  
  RESULTS
  The incidence of intraneural injection during regional anesthesia is higher than previously appreciated. Defining intraneural injection and its significance are the subject of current debate. Clinical studies with small sample sizes suggest that intraneural injection may not necessarily be responsible for nerve injury. Inflammatory mechanisms may contribute to perioperative nerve injury. Ultrasound guidance has not been proven to reduce the incidence of nerve injury due to peripheral nerve blockade (PNB). Increased utilization of PNB is not associated with an increase in perioperative nerve injury.
  
  
  CONCLUSIONS
  The pathogenesis of perioperative nerve injury is complex with multiple potential etiologies and mechanisms. The role of intraneural injections as a modifiable risk factor for neurologic complications due to regional anesthesia remains topical. Relevant publications include studies on the morphology of peripheral nerves and risk of perioperative nerve injury in the context of both neuraxial anesthesia and PNB.
authors.affiliation: Department of Anaesthesia, St. Vincent's Hospital, Melbourne, Australia. Michael.Barrington@svhm.org.au
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Barrington
authors.forename: Gabriel L
authors.initials: GL
authors.lastname: Snyder
mesh_terms: D000765:Anesthesia, Conduction / Q000009:adverse effects*; D006801:Humans; D007431:Intraoperative Complications / Q000139:chemically induced / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D009407:Nerve Block / Q000009:adverse effects; D010525:Peripheral Nerves / Q000000981:diagnostic imaging; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography