Fig. 1. Sensory function 4 and 7 days after intrathecal administration of 5% lidocaine, 5% lidocaine with epinephrine (0.2 mg/ml; Lido + Epi), epinephrine (0.2 mg/ml), or saline. Tail-flick latency values were calculated as the average of latencies for the proximal, middle, and distal portions of the tail and are expressed as percent maximum possible effect (MPE):[(tail-flick latency − baseline)/(cutoff − baseline)]× 100. Data represent mean ± SD. * P < 0.05 versus  epinephrine or saline. ** P < 0.05 versus  all other groups.