Prospective, Randomized Comparative Study of an Anesthesiological, Ultrasound-Guided "Erector Spinae Plane Block" (ESPB) Versus a Surgical, Thoracoscopically-Guided "Intercostal Nerve Block" (ICNB) in "Video-Assisted Thoracoscopic" (VATS) Procedures, Evaluating Postoperative Analgesic Consumption, Postoperative Pain Perception, and Duration of the Procedure

Effective postoperative pain management is essential after thoracic surgery, as insufficient pain control may impair breathing and increase the risk of pulmonary complications such as atelectasis or pneumonia. Although video-assisted thoracoscopic surgery (VATS) is less invasive than open thoracotomy, patients may still experience significant postoperative pain.

This single-center, prospective, randomized non-inferiority study with two parallel arms compares two commonly used regional anesthesia techniques for perioperative pain management in adult participants undergoing elective VATS lung resections: the Erector Spinae Plane Block (ESPB) and the Intercostal Nerve Block (ICNB). Both techniques have been shown to reduce postoperative pain and opioid consumption. However, existing comparative studies have reported inconsistent results, and direct comparisons are limited by differences in techniques and study design.

After informed consent, participants are randomized preoperatively using a sealed-envelope system to receive either an ultrasound-guided ESPB or a thoracoscopically-guided ICNB.

The ESPB is performed by anesthesiologists before induction of general anesthesia, whereas the ICNB is performed intraoperatively by the surgeon under thoracoscopic visualization. Both interventions use a standardized dose of 25 mL ropivacaine 0.375% prior to the start of the surgical procedure. Perioperative anesthesia and analgesia management are standardized across both groups to ensure comparability and to minimize confounding effects.

The primary objective is to evaluate whether ESPB is non-inferior to ICNB with respect to postoperative analgesic consumption within the first 24 hours after surgery. The non-inferiority margin is defined as 5 mg piritramide within 24 hours. This margin was selected as it corresponds to the upper limit of a commonly used bolus dose in routine clinical practice and represents a clinically meaningful difference.

Secondary objectives include the comparison of postoperative pain perception within the first 24 hours and the duration of the chest wall block procedure. The incidence of postoperative nausea and vomiting (PONV) and procedure-related complications is also assessed.

The sample size calculation is based on the primary non-inferiority endpoint. Estimates of variability were derived from published data on postoperative opioid consumption following VATS. Using a one-sided significance level of 0.025, a statistical power of 90%, and a 1:1 allocation ratio, and accounting for a dropout rate of 10%, a total of 72 participants will be enrolled.

Statistical analysis will follow the non-inferiority design, comparing postoperative analgesic consumption between groups with respect to the predefined margin, while secondary outcomes will be analyzed using appropriate descriptive and inferential statistical methods.