Two-Point Versus Single-Point Serratus Anterior Plane Block for Post-Thoracoscopic Surgery Analgesia

Postoperative pain remains a common clinical challenge in patients undergoing video-assisted thoracoscopic surgery (VATS), impairing early recovery and increasing opioid consumption. The serratus anterior plane block (SAPB) is a widely used regional analgesic technique for thoracic surgery, but conventional single-point injection may have limited spread of local anesthetics, resulting in suboptimal analgesia in some patients. Preliminary anatomical evidence suggests that two-point combined SAPB may achieve wider dermatomal coverage and better analgesic efficacy. This is a single-center, prospective observational cohort study conducted at Shanghai Pulmonary Hospital, China. A total of 88 adult patients scheduled for elective unilateral VATS will be consecutively enrolled and naturally assigned to either the two-point combined SAPB group (injection at the 3rd and 5th rib levels, total 30 ml local anesthetic) or the single-point SAPB group (injection at the 5th rib level, 30 ml local anesthetic) according to routine clinical practice. The primary outcome is the verbal rating scale (VRS) pain score on coughing at 24 hours postoperatively. Secondary outcomes include resting and dynamic pain scores at multiple time points, cumulative opioid consumption at 24 and 48 hours, incidence of postoperative nausea and vomiting, block-related complications, length of hospital stay, and Quality of Recovery-15 (QoR-15) scores. This study aims to provide clinical evidence for optimizing perioperative analgesic strategies for thoracoscopic surgery.

Inclusion Criteria: * Aged 18 to 85 years at enrollment, regardless of sex * American Society of Anesthesiologists (ASA) physical status grade I to III * Scheduled for elective unilateral video-assisted thoracoscopic surgery * Planned to receive ultrasound-guided SAPB for routine perioperative analgesia * Able to understand study procedures and provide written informed consent Exclusion Criteria: * Local infection or skin lesion at the block puncture site * Known hypersensitivity or allergy to amide local anesthetics * Preexisting sensory abnormality in the chest wall surgical area * Chronic opioid use for \> 3 months, history of chronic pain syndrome, or history of opioid abuse * Severe coagulopathy (international normalized ratio \> 1.5 or platelet count \< 80 × 10⁹/L) * Cognitive impairment or inability to cooperate with postoperative pain assessment * Refusal to provide written informed consent