Effect of a T4 erector spinae plane block on post-thoracoscopic shoulder pain: protocol for an assessor-blinded randomized controlled trial using ropivacaine and dexamethasone

Effective pain management following thoracic surgery is a critical clinical issue. Neglecting to manage acute postoperative pain in a timely manner may result in its transition to a chronic state. Notably, ipsilateral shoulder pain is one of the common complications observed after thoracic surgical procedures. The incidence of shoulder pain following thoracoscopic surgery is approximately 21%. Severe shoulder pain not only impairs respiratory function and delays postoperative recovery but also leads to shoulder dysfunction and reduced patient satisfaction. Recent investigations have highlighted the efficacy of the erector spinae plane (ESP) block in providing robust analgesia across diverse anatomical regions, encompassing the cervical, thoracic, and abdominal areas. Characterized by its notable analgesic potency, ease of execution, and extensive range of action, the ESP block has garnered widespread application for postoperative pain management in thoracic surgical procedures. Cadaveric studies suggest that injectate placed at the T4–T5 level may reach cervical levels relevant to shoulder innervation. Dexamethasone has been used as an adjunct to local anesthetics in peripheral nerve blocks. The present trial evaluates a fixed T4 ESPB regimen containing ropivacaine and dexamethasone as an addition to standardized intravenous analgesia; it is not designed to determine the independent effect of dexamethasone. This single-center, two-arm, parallel-group Randomized controlled trial will include 104 adults undergoing thoracoscopic surgery. Participants will be assigned 1:1 to standardized perioperative intravenous analgesia plus a unilateral T4 ESPB with 30 mL of 0.25% ropivacaine and 8 mg dexamethasone (Group E, n = 52), or the same standardized intravenous analgesia without an ESPB (Group B, n = 52). Postoperative outcome assessors and the statistician will be blinded to allocation; the anesthesiologist performing the block cannot be blinded. The primary outcome is the proportion of participants with ipsilateral shoulder pain at 24 h after surgery, defined as a resting or coughing shoulder-pain VAS score >1 on a 0–10 scale. Secondary outcomes include repeated binary shoulder-pain status (present when either the resting or coughing shoulder-pain VAS is >1) and separate resting and coughing shoulder- and incisional-pain VAS scores at 1, 2, 4, 8, and 24 h; perioperative opioid consumption; rescue analgesia; postoperative nausea and vomiting and antiemetic use; the 24-h QoR-15 score; operative, anesthesia, and PACU durations; time to first ambulation; chest-tube duration; hospital stay; and adverse events. This trial will evaluate whether adding the complete T4 ESPB regimen containing ropivacaine and dexamethasone to standardized intravenous analgesia reduces post-thoracoscopic shoulder pain. If positive, the findings may help refine multimodal postoperative analgesia. Because the comparator receives no ESPB, any between-group difference cannot be attributed specifically to dexamethasone. ChiCTR2400092686. Registered on November 21, 2024.