RT Journal Article SR Electronic T1 A New Step Toward Evidence of In Vivo Perineural Dexamethasone Safety: An Animal Study JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 180 OP 185 DO 10.1097/AAP.0000000000000392 VO 43 IS 2 A1 Philippe Marty A1 Mehdi Bennis A1 Benjamin Legaillard A1 Etienne Cavaignac A1 Fabrice Ferre A1 Julie Lebon A1 Anne Brouchet A1 Vincent Minville YR 2018 UL http://rapm.bmj.com/content/43/2/180.abstract AB Background and Objectives The aim of this study was to analyze histological nerve toxicity of perineural dexamethasone administration in combination with ropivacaine on mice. Efficacy of perineural dexamethasone in combination with regional anesthesia is clearly demonstrated. However, the safety of this procedure is still a matter of debate.Methods A sciatic nerve block was performed on 90 mice. Five groups, each containing 18 mice assigned randomly, were used in these experiments: the sham group (isotonic saline solution), R group (perineural ropivacaine), D group (perineural dexamethasone), RDPN group (perineural ropivacaine and perineural dexamethasone), and the RDS group (perineural ropivacaine and systemic dexamethasone). Sensory and motor blocks were evaluated every 30 minutes for 14 hours. Fourteen and 28 days after this procedure, 9 mice in each group were killed for sciatic nerve histological assessment.Results No statistical difference was observed between different groups for Wallerian degeneration (P = 0.28 at day 14 and P = 0.22 at day 28) and perineural inflammation (P = 0.9 at day 14). Motor and sensory block durations were tested for each group. A statistical difference was observed for motor block duration between the RDPN group (150 minutes [127–172 minutes]), the RDS group (120 minutes [90–120 minutes]), and the R group (60 minutes [60–90 minutes]). Sensory block duration was also statistically different: 660 minutes (660–720 minutes) in the RDPN group, 480 minutes (427–660 minutes) in RDS group, 330 minutes (240–410) in the R group.Conclusions A combination of ropivacaine and perineural dexamethasone allows longer sensory block duration compared with ropivacaine alone or ropivacaine and systemic dexamethasone, without increased neural toxicity.