| Background: Chronic post-surgical pain(CPSP)is a challenging problem after breast cancer surgery.There has been increasing interest in serratus anterior plane block(SAPB)as a simple and safe alternative for analgesia after surgery.However,the influence of SPB on chronic pain following modified radical mastectomy has still not been elucidated.We conducted this prospective randomized study to evaluate the efficacy of pre-operative ultrasound-guided SAPB on both acute postoperative pain and chronic pain following modified radical mastectomy.Methods: One hundred and ninety-six women scheduled for modified radical mastectomy were randomly allocated to receive pre-operative ultrasound-guided SAPB with 25 ml of ropivacaine 0.5% or normal saline.The primary outcome was the rate of pain three months after surgery(numeric rating scale >3).Secondary outcomes were acute postoperative pain,postoperative opioid consumption,quality of recovery(the gobal QoR-15 score),length of post-anesthesia care unit(PACU)stay,postoperative nausea and vomiting(PONV),dizziness,SAPB-related adverse events,and the rate of pain six months after surgery.Results: A total of 182 patients randomized and completed the trial.Pre-operative SAPB with ropivacaine 0.5% reduced chronic pain at three postoperative months from 36/90(40%)to 19/92(21%),relative risk(95% CI)0.52(0.32-0.83),P=0.004.Similarly,the rate of chronic pain was reduced at six months from 26/90(29%)to10/92(11%),relative risk(95% CI)0.38(0.19-0.73),P=0.002.Besides,the median global QoR-15 score 24 hours postoperatively was 120(IQR,116 to 123)among patients in the SAPB group and 112(IQR,109 to 114)among patients in the control group(P<0.001),with an estimated median difference of 8(95%CI,7 to 10).Ropivacaine serratus plane block reduced acute postoperative pain at rest and on movement during the first 24 hours,P<0.05 for both.Median postoperative sufentanil consumption within initial 48 postoperative hours was 48μg(IQR,48 to 52μg)in the SAPB group and 60μg(IQR,57.5-64μg)in the control group(P<0.001),with an estimated median difference of-10.2μg(95% CI,-11.5 to-8.9μg).Median AUC of NRS pain score at rest through initial 48 postoperative hours was 62.5(IQR,51.5 to80.3)in the SAPB group and 84.4(IQR,71.9 to 93.0)in the control group(P<0.001),with an estimated median difference of-17.4(95%CI,-22.3 to-12.9);Median AUC of NRS pain score on movement through initial 48 postoperative hours was86.7(IQR,71.6 to 97.2)in the SAPB group and 101.8(IQR,92.5 to 110.1)in the control group(P<0.001),with an estimated median difference of-15.1(95%CI,-19.9 to-10.6).The rate of PONV was also reduced from 12/90 to 4/92,relative risk(95% CI)0.30(0.09-0.95),P=0.032.Additionally,compared with the control group,preoperative SAPB reduced the length of PACU stay(difference,-7.7 min;95%CI,-8.3 to-7.0min)and improved patient satisfaction(difference,2;95%CI,2 to 3),P<0.001 for both.No SAPB-related complications occurred.Conclusion: Pre-operative ultrasound-guided SAPB with ropivacaine improved acute postoperative pain and quality of recovery,and decreased the rate of chronic post-surgical pain at three and six months after modified radical mastectomy. |
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