Neurologic complications of regional anesthesia.

PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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.

Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications.

BACKGROUND AND OBJECTIVES: Peripheral nerve blockade is associated with excellent patient outcomes after surgery; however, neurologic and other complications can be devastating for the patient. This article reports the development and preliminary results of a multicenter audit describing the quality and safety of peripheral nerve blockade. METHODS: From January 2006 to May 2008, patients who received peripheral nerve blockade had data relating to efficacy and complications entered into databases. All patients who received nerve blocks performed by all anesthetists during each hospital's contributing period were included. Patients were followed up by phone to detect potential neurologic complications. The timing of follow-up was either at 7 to 10 days or 6 weeks postoperatively, depending on practice location and time period. Late neurologic deficits were defined as a new onset of sensory and/or motor deficit consistent with a nerve/plexus distribution without other identifiable cause, and one of the following: electrophysiologic evidence of nerve damage, new neurologic signs, new onset of neuropathic pain in a nerve distribution area, paresthesia in relevant nerve/plexus distribution area. RESULTS: A total of 6950 patients received 8189 peripheral nerve or plexus blocks. Of the 6950 patients, 6069 patients were successfully followed up. In these 6069 patients, there were a total of 7156 blocks forming the denominator for late neurologic complications. Thirty patients (0.5%) had clinical features requiring referral for neurologic assessment. Three of the 30 patients had a block-related nerve injury, giving an incidence of 0.4 per 1000 blocks (95% confidence interval, 0.08-1.1:1000). The incidence of systemic local anesthetic toxicity was 0.98 per 1000 blocks (95% confidence interval, 0.42-1.9:1000). CONCLUSIONS: These results indicate that the incidence of serious complications after peripheral nerve blockade is uncommon and that the origin of neurologic symptoms/signs in the postoperative period is most likely to be unrelated to nerve blockade.