Effects of ultrasound-guided serratus anterior plane block on post-mastectomy pain syndrome

Abstract:

Objective：To investigate the effect of ultrasound-guided serratus anterior plane block on perioperative analgesia in patients after modified radical mastectomy（MRM） and to explore its role in preventing post-mastectomy pain syndrome（PMPS）. Methods：One hundred female patients scheduled for modified radical mastectomy，aged 28 to 75，were randoly divided into 2 groups the general anesthesia group（G） and the general anesthesia group combined with nerve block group（GB）. Before induction of anesthesia，patients in the GB group were injected with 0.33% ropivacaine for 30 mL in the serratus anterior plane under ultrasound guidance. Patients in the group G were injected with the same amount of saline at the same location. Patients in the two groups underwent tracheal intuba－tion，followed by static suction combined anesthesia. Patients in both groups were given patient controlled intravenous analgesia（PCIA） after surgery. The times of effective delivered doses 48 h postoperatively，the cases of remedial analgesia were recorded. Nu－merical rating scale（NRS） was used to evaluated the pain severity at 4 hours，12 hours，24 hours，and 48 hours postoperatively and at 3 months，6 months，9 months，12 months postoperatively in both groups. PMPS incidence will also be recorded. Results：①The NRS scores at rest in GB group were significantly lower than that of the G group at 4 h（P=0.000），12 h（P=0.000），24 h（P=0.000），and 48 h（P=0.001） postoperatively；NRS scores at movement in in GB group were significantly lower than that of the G group at 4 h（P=0.000），12 h（P=0.000），24 h（P=0.002），and 48 h（P=0.001） postoperatively. ②The number of effective analgesia pump pressing within 48 h in GB（0.07±0.34） was signifi－cantly less than that in the G group（0.56±0.82）（P=0.001）；the remedial analgesic ratio in GB group（4.77%） was lower than G group（35.90%）（P=0.000）. ③The NRS scores in the GB group at 6（P=0.020） and 9 months（P=0.016） after surgery were significantly lower than those in the G group. ④The incidence of PMPS in GB group at 6 months（47.62%） and 9 months（61.54%） postopera－tively was significantly lower than that in the G group at 6 months（71.80%，P=0.041） and 9 months（61.54%，P=0.020）postopera－tively. ⑤There was a correlation between the acute NRS scores and the chronic NRS scores. Conclusion：Ultrasound-guided serratus anterior plane block applied to modified radical mastectomy for breast cancer can not only improve acute pain scores，reduce periop－erative opioid consumption，but also reduce the incidence and severity of PMPS. In addition，the postoperative acute pain NRS score was related to the severity of PMPS.