A repeated measures analysis of variance showed that subjects receiving treatment with bupivacaine experienced a significant reduction in the numeric rating scale scores compared with those receiving saline at baseline ( M = 3.78 vs M = 3.18 , P = .10 ) , 15 minutes ( M = 3.51 vs M = 2.53 , P < .001 ) , 30 minutes ( M = 3.45 vs M = 2.41 , P < .001 ) , and 24 hours after treatment ( M = 4.20 vs M = 2.85 , P < .001 ) , respectively .