Effect of liposomal bupivacaine combined with bupivacaine hydrochloride for transversus thoracic muscle plane block and pectoral nerves block in modified radical mastectomy for breast cancer: protocol for a randomised controlled trial.

INTRODUCTION: The incidence of acute pain subsequent to modified radical mastectomy (MRM) for breast cancer approximates 40%, with more than half of these cases evolving into chronic pain. Currently, the commonly employed analgesic schemes in clinical practice still have inadequacies. Liposomal bupivacaine (LB) is bupivacaine encapsulated in liposomes, and it is reported that its duration of action can extend up to 72 hours. This study will investigate the analgesic efficacy of LB in combination with bupivacaine hydrochloride (BHCl) for transversus thoracic muscle plane (TTP) block and pectoral nerves (PECS) block after MRM for breast cancer. METHODS AND ANALYSIS: In this prospective, randomised, controlled trial, we will enrol 80 female patients aged 30 to 65 years who are scheduled to undergo MRM under general anaesthesia in combination with nerve block. They will be randomly assigned in a 1:1 ratio to the LB+BHCl group (Group A) and the BHCl group (Group B). All patients will undergo ultrasound-guided TTP+PECS block prior to surgery. The primary outcomes are the cumulative pain visual analogue scale (VAS) scores from 6 to 72 hours post-surgery and the quality of recovery, assessed using the QoR-40 score at 72 hours post-surgery. The secondary outcomes include the time to first analgesic rescue, the consumption of analgesic drugs within 72 hours postoperatively, the occurrence of adverse events and the VAS scores at 6 and 12 months postoperatively. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Ethics Committee of the Affiliated Hospital of Yangzhou University (2024 Ke Lun Shen (2024-07-01)). All patients will provide written informed consent. The results of this study will be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2400089933).