Fig. 2. Postoperative opioid analgesic requirements in the control (gray bars ), bupivacaine-0.25% group (black bars ), and bupivacaine-0.5% group (white bars ) that were assessed using patient-controlled analgesia (PCA) morphine use during the first 72 h after surgery. *P < 0.05, values significantly different from those of the control group.