Continuous Serratus Anterior Versus Erector Spinae Plane Block Catheters for Postoperative Pain Management Following Video-Assisted Thoracoscopic Surgery: A Retrospective Study

Introduction: Optimal pain management following video-assisted thoracoscopic surgery (VATS) is key to promoting efficient recovery while minimizing the incidence of postoperative complications. Regional anesthesia can help achieve greater pain control, fostering enhanced recovery and increased patient satisfaction, though debate remains over the most effective technique for VATS. This study sought to compare the analgesic efficacy of two continuous regional anesthetic techniques commonly used for VATS, the serratus anterior plane block (SAPB or CSAPB) and the erector spinae plane block (ESPB or CESPB). This study also sought to identify the clinical benefits of regional anesthesia (CSAPB or CESPB) versus no regional anesthesia in the setting of VATS. Methods: A retrospective study was conducted, including 397 adult patients who underwent VATS and received multimodal analgesia. Postoperative outcomes were compared among patients who received CSAPB versus those who received CESPB; these outcomes were also compared between patients who received either regional anesthesia technique (CSAPB or CESPB, block group) and patients who did not receive regional anesthesia (non-block group). Co-primary outcomes included opioid consumption during hospital admission (presented as morphine milligram equivalents) and pain (minimum, maximum, and average numeric pain scale scores) in the first 72 postoperative hours. Secondary postoperative outcomes included post- anesthesia care unit (PACU) length of stay, time from procedure end to discharge, time to first opioid medication, ambulation distance on day one, medication use, and incidence of surgical or block-related complications. All data were retrospectively obtained from patients' electronic medical records. Results: Comparing regional anesthesia techniques, patients who received CESPB reported lower pain with activity postoperatively than patients who received CSAPB (3.6 vs. 4.2, p=0.009). There were no other significant differences in postoperative outcomes between these groups. Comparing the block and non- block groups, the block group exhibited a higher overall comorbidity burden than the non-block group (p=0.001). Even so, the block group reported less postoperative pain at rest and with activity than the non- block group (mean: 3.6 vs. 4.1, p=0.012; mean 3.8 vs. 4.4, p=0.012). PACU stay and time to discharge were longer in the block group than non-block group (3.3 vs. 2.6 hours, p=0.004 and 3.1 vs. 2.9 days, p=0.012, respectively). However, the block group ambulated a significantly longer distance than the non-block group on the first postoperative day (median: 181.1 m vs. 73.2 m, p<0.001). The block group more often received acetaminophen and/or aspirin and gabapentinoids than the non-block group (94.5% vs. 75.0%, p<0.001 and 84.8% vs. 62.0%, p<0.001, respectively). Conclusion: Both CESPB and CSAPB are effective regional anesthesia techniques for VATS postoperative pain management with clear clinical benefits over no regional anesthesia. A direct comparison of the analgesic efficacy of CESPB versus CSAPB indicated that CESPB is more effective than CSAPB in terms of pain control. These findings are consistent with existing literature and most recent practice recommendations.