Video-Assisted Thoracoscopic Surgery (VATS) is a minimally invasive surgery. Despite reduced surgical trauma compared to the traditional thoracotomy approach, pain control after VATS remains challenging. Regional analgesia may be a crucial component of multimodal postoperative pain management. The use of nerve blocks, such as the recently described erector spinae plane block (ESPB) has been shown in case reports to reduce pain and thus has the potential to improve patient recovery. This study aims to test the hypothesis that ultrasound-guided SPB would improve the quality of recovery after VATS by reducing acute postsurgical pain.

VATS is a minimally invasive surgical technique to remove intrathoracic lesions. VATS has become increasingly popular and gradually becoming the standard of care for lung surgery. Although acute pain after VATS is less than the traditional thoracotomy, patients still experience moderate amount of pain within the first 24 hours. However, the optimal regional analgesic technique for VATS procedures has not been established.

Thoracic epidural analgesia (TEA) and paravertebral block (PVB) have been tried to improve postoperative analgesia after VATS. Although TEA and PVB provides superior analgesia, these technologies accompanied by the rare but serious complications involving epidural hematoma, pneumothorax and total spinal anesthesia.

Erector spinae plane block (ESPB) is a novel and simple ultrasound-guided regional anesthetic technique, providing analgesia for the ipsilateral hemithorax. Ultrasound guidance is believed to improve peripheral and regional nerve block success rates and safety. ESPB is a technically easy to perform. ESPB has only been reported in case series but so far, no adverse events such as hypotension, hematoma or infection has been reported.

Given its safety, ease of performance and efficacy, the study aims to verify the hypothesis that combines ESPB with general anesthesia would accelerate functional recovery after breast cancer surgery. Our secondary aims were to examine ESPB's effect on analgesic outcomes (e.g., postoperative pain intensity, cumulative opioid consumption, postoperative nausea and vomiting, dizziness, the postanesthesia care unit discharge time and patients' satisfaction) in patients undergoing VATS.

Inclusion Criteria:

• American Society of Anesthesiologists' physical status class of I or II
• scheduled for elective VATS

Exclusion Criteria:

• a history of allergy to local anesthetics
• known coagulation disorders
• infection near the puncture site
• chronic opioid use
• inability to communicate,
• other reasons that not appropriate for this study.

It is not yet known if there will be a plan to make individual participant data (IPD) available.

Beginning 3 months and ending 3 years following article publication.

All of the individual participant data collected during the trial, the study protocol, statistical analysis plan, and clinical study report can be accessed with approval from the corresponding author.

The randomization sequence will be computer generated. Allocation concealment will be carried out via concealed assignments in opaque, sealed, and consecutively numbered envelopes.