Application of a new serratus anterior plane block in modified radical mastectomy under ultrasound guidance: A prospective, randomized controlled trial

Abstract

Study objectives: Post-operative pain is a significant concern following modified radical mastectomy in breast cancer patients. The serratus anterior plane block has recently been described as an effective technique for post-operative analgesia of modified radical mastectomy. The purpose of this study was to evaluate the analgesic efficacy and safety of a new serratus anterior plane (SAP) block for post-operative pain of mastectomy.

Design: A randomized controlled trial.

Setting: Single university teaching hospital, from October 2019 to April 2020.

Patients: Eighty-seven female breast cancer patients aged 30-81 years scheduled for unilateral modified radical mastectomy.

Interventions: Participants were randomly allocated to receive either general anesthesia plus SAP block (SAP block group, n = 43) or general anesthesia alone (Control group, n = 44). A single injection of 20 ml of 0.5% ropivacaine was administered into fascial plane between the pectoralis major and the serratus anterior in SAP block group. In the Control group, no block intervention was applied.

Measurements: The primary outcome measure of the study was the VAS pain scores at different time-points (1, 6, 12, 24, 48 h) after modified radical mastectomy whereas the secondary outcome measures were the consumption of opioid analgesics.

Main results: Breast cancer patients in SAP block group had lower VAS pain scores compared with the Control group during the early post-operative period (1 h and 6 h after modified radical mastectomy), both at rest and with movement. In addition, the consumption of propofol was similar in two groups (P = 0.406), and the consumption of sufentanil and remifentanil in SAP block group were significantly lower than that of Control group (P = 0.000 and P = 0.000, respectively).

Conclusions: SAP block significantly attenuated post-operative pain and decreased opioids consumption in breast cancer patients undergoing modified radical mastectomy.

Trial registration: This trial is registered in the Chinese Clinical Trial Registry (ChiCTR1900026989).

Keywords: Modified radical mastectomy; Opioid consumption; Post-operative pain; Serratus anterior plane block.