Discharge times for knee arthroscopy in spinal vs. general anesthesia

BackgroundSpinal anesthesia (SPA) and general anesthesia (GA) are both safe techniques for knee arthroscopy. In this prospective, single-centre, randomised, clinical trial we compared the discharge times of SPA using 50mg hyperbaric prilocaine 2% and GA with propofol and sufentanil in patients undergoing ambulatory knee arthroscopy.Methods50 patients (18–80 years / American Society of Anaesthesiologists grade I–III) were randomized equally to receive either SPA or GA. The main outcome variable was the time until discharge from the day-surgery centre. Anesthesia related side effects, postoperative analgesics and patient satisfaction were assessed.ResultsTwo of the spinal blocks failed and GA had to be provided. Despite of a faster recovery (unassisted ambulation: SPA: 90 (90–295)min vs. GA: 156 (93–235)min, p=0.0029), spontaneous voiding led to a delayed discharge in the SPA group (SPA: 240 (135–295)min vs. GA: 156 (93–235)min, p<0.0001). There were no differences between the groups regarding other anesthesia related side effects, postoperative demand of analgesics or patient satisfaction.ConclusionSPA with 50mg hyperbaric prilocaine 2% leads to a later discharge than GA with sufentanil and propofol. However, a reevaluation of existing discharge recommendations including obligatory micturition is necessary, to make SPA become even more advantageous for ambulatory surgery.