Bupivacaine and morphine group had similar acute postoperative pain scores ( WMD : @ ; @ % CI , -@ to @ ; P = @ ) ; number of patients requiring supplementary analgesia ( relative risk : @ ; @ % CI , @ to @ ; P = @ ) for the trials in this meta-analysis ( n = @ ) ; and side effects ( relative risk : @ ; @ % CI , @ to @ , P = @ ) .