Comparing Quality of Recovery Between ESPB and IV Lidocaine After Major Breast Cancer Surgery

Major Breast Cancer Surgery (BCS), including mastectomy or modified radical mastectomy (MRM), is a globally prevalent procedure. Unfortunately, it is associated not only with significant acute postoperative pain but also a high incidence of chronic postsurgical pain (30-50%) . To improve outcomes, regional anesthetic techniques have been explored, including thoracic paravertebral block (TPVB) and ultrasound-guided erector spinae plane block (ESPB). While TPVB is considered the gold standard, it carries potential complications such as pleural puncture and pneumothorax. In contrast, ultrasound-guided (USG) ESPB is gaining popularity due to its technical simplicity and safety. However, controversy surrounds its mechanism of action, particularly the variable cutaneous sensory loss over anterior thoracic dermatomes. An emerging theory suggests that ESPB's clinical analgesia results from rapid and sustained local anesthetic (LA) absorption from the injection site. As an alternative, intravenous LA infusion (IVLI) during the perioperative period may offer equivalent analgesia without the invasiveness of ESPB. IV lidocaine, known for its substantial analgesic properties, persists beyond its typical duration of action, likely through mechanisms beyond sodium channel blockade. Although IV lidocaine has been established as part of multimodal analgesia in various perioperative settings, data specific to major BCS remain scarce. In this prospective, multicenter, randomized, triple-blind trial, the investigators aim to compare quality of recovery (assessed using the validated Quality of Recovery 15 \[QoR15\] score) between USG ESPB and IVLI. The investigator's hypothesis is that the quality of recovery after major breast cancer surgery with IVLI will be comparable to that achieved with USG ESPB.