Figure 1: Duration of anesthesia in the 2 patient groups. Minimum duration of anesthesia for bupivacaine is 4 hours, maximum duration is 9.8 hours, the IQR is 5.8-8.7 hours and the median is 7.2 hours. For ropivacaine, minimum duration of anesthesia is 3.75 hours, maximum duration is 9 hours, the IQR is 5.1-7.04 hours, and the median is 6 hours.