Evaluation of Pectoral Nerve Block in Modified Radical Mastectomy: Comparison of Three Concentrations of Ropivacaine

BACKGROUND: Pectoral nerve block type I (PECS I Block) and type II (PECS II Block) with ropivacaine are relatively new analgesic methods for breast-cancer surgery. We evaluated the safety and efficacy of different concentrations of ropivacaine given in the same volume for the PECS II Block in patients undergoing modified radical mastectomy (MRM). PATIENTS AND METHODS: One hundred and twenty women undergoing elective MRM who met inclusion criteria were divided randomly into four groups of 30: control group without PECS II Block and R(0.2%), R(0.3%), and R(0.4%) groups, who received general anesthesia plus the PECS II Block with ropivacaine at 0.2%, 0.3%, and 0.4%, respectively, in a volume of 40 mL. RESULTS: The postoperative numerical rating scale (NRS) pain score at rest and active was significantly higher in the control group than that in the three ropivacaine groups (P<0.05 for all), and the postoperative NRS score in the R(0.3%) group and R(0.4%) group at 12, 24, and 48 h postoperatively were significantly lower than that in the R(0.2%) group (P<0.05 for all); there was no significant difference between the R(0.3%) group and R(0.4%) group. The time when pain was first felt after MRM, the total number of complaints during 3, 6, 12, 24, and 48 h after MRM, and the total analgesic requirement (tramadol consumption) during the first 24 h postoperatively in the R(0.3%) group and R(0.4%) group were significantly lower than those in the control group and R(0.2%) group (P<0.05 for all); there was no significant difference between the R(0.3%) group and R(0.4%) group. CONCLUSION: A dose of 0.3% ropivacaine was the optimal concentration for a PECS II Block for patients undergoing MRM because it provided efficacious analgesia during and >48 h after MRM. Increasing the ropivacaine concentration did not improve the analgesia of the PECS II Block significantly.