Fig. 5. Sensory function 4 days after a 1-h intrathecal infusion of 2.5% levobupivacaine (n = 21), 2.5% bupivacaine (n = 17), 2.5% dextrobupivacaine (n = 19), or normal saline (n = 17). Tail-flick (TF) latencies were converted to the percent maximal possible effect (%MPE), calculated as (postdrug value − baseline value)/(cutoff value − baseline value) × 100%. Data are presented as mean ± SEM. * P < 0.05 compared with saline.