Spinal hyperbaric prilocaine vs. mepivacaine in perianal outpatient surgery

BackgroundThe aim of this randomised, clinical trial was to compare safety and efficiency of hyperbaric prilocaine and mepivacaine at a dosage of 0.5 ml each for perianal outpatient surgery in terms of transient neurologic symptoms (TNS) and postoperative recovery.Methods160 patients aged 18–80 years were randomized to receive a spinal anaesthesia (SPA) with 0.5ml of mepivacaine or prilocaine. We measured the expansion of the block, evaluated postoperative recovery times and determined the incidence of TNS one week after surgery.Results160 patients (93 male / 67 female) were available for analysis. Prilocaine led to shorter times from SPA to micturition (prilocaine: 178 (110–254) min vs. mepivacaine: 195 (130–305) min, p=0.0008) and discharge (prilocaine: 192 (126–267) min vs. mepivacaine: 220 (140–320) min, p<0.0001). 152 / 160 patients were available for the telephone follow-up. Six patients (9%) receiving mepivacaine compared to zero patients of the prilocaine group announced typical symptoms of TNS (p=0.0284).ConclusionBoth, hyperbaric mepivacaine 40 mg/ml and hyperbaric prilocaine 20 mg/ml can be used at a dosage of 0.5 ml each for SPA in perianal outpatient surgery. Due to the faster recovery profile and a lower incidence of TNS, we recommend the use of 10mg hyperbaric prilocaine 20 mg/ml for this indication.