Infectious complications following regional anesthesia: A narrative review and contemporary estimates of risk

Introduction: Infectious complications following regional anesthesia (RA) while rare, can be devastating. The objective of this review was to estimate the risk of infectious complications following central neuraxial blocks (CNB) such as epidural anesthesia (EA), spinal anesthesia (SA) and combined spinal epidural (CSE), and peripheral nerve blocks (PNB). Materials and methods: A literature search was conducted in PubMed, Embase and Cochrane databases to identify reference studies reporting infectious complications in the context of RA subtypes. Both prospective and retrospective studies providing incidence of infectious complications were included for review to provide pooled estimates (with 95% CI). Additionally, we explored incidences specifically associated with spinal anesthesia, incidences of central nervous system (CNS) infections and, the incidences of overall and CNS infections following CNB in obstetric population. Results: The pooled estimate of overall infectious complications following all CNB was 9/100 000 (95% CI: 5, 13/100 000). CNS infections following all CNB was estimated to be 2/100 000 (95% CI: 1, 3/100 000) and even rarer following SA (1/100 000 (95% CI: 1, 2/100 000)). Obstetric population had a lower rate of overall (1/100 000 (95% CI: 1, 3/100 000)) and CNS infections (4 per million (95% CI: 0.3, 1/100 000)) following all CNB. For PNB catheters, the reported rate of infectious complications was 1.8% (95% CI: 1.2, 2.5/100). Discussion: Our review suggests that the risk of overall infectious complications following neuraxial anesthesia is very rare and the rate of CNS infections is even rarer. The infectious complications following PNB catheters seems significantly higher compared with CNB. Standardizing nomenclature and better reporting methodologies are needed for the better estimation of the infectious complications.