Superficial parasternal intercostal plane block reduces 24-hour morphine use by 8.53 mg in cardiac surgery patients

BACKGROUND: Effective postoperative pain control is essential for enhanced recovery after cardiac surgery, yet optimal multimodal strategies continue to evolve. The superficial parasternal intercostal plane (S-PIP) block has been proposed as a simple and safe technique for median sternotomy analgesia; however, current evidence remains fragmented, and its clinical impact is unclear. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials assessing the analgesic efficacy and safety of the S-PIP block in adult cardiac surgery. PubMed, Embase, CENTRAL, Web of Science, Scopus, ClinicalTrials.gov, and gray literature were searched through September 2025. Trials comparing S-PIP with standard or placebo analgesia were pooled using a random-effects model. The primary outcome was 24-hour opioid use (morphine milligram equivalents). Trial sequential analysis, meta-regression, and Grades of Recommendation, Assessment, Development, and Evaluation were applied to evaluate the robustness and certainty of evidence. RESULTS: Twenty-seven randomized controlled trials (1,760 patients) met the inclusion criteria. S-PIP block significantly reduced 24-hour opioid use compared with control (mean difference, -8.53 mg; 95% CI, -14.39 to -2.68), although the reduction was below the minimal clinically important difference and demonstrated substantial heterogeneity (I = 98.1%). Trial sequential analysis confirmed statistical significance, but the required sample size was not achieved. The block also lowered early pain scores, reduced rescue analgesic use, and shortened extubation time and intensive care unit stay. No meaningful differences were observed in hospital stay, postoperative nausea and vomiting, or chronic postsurgical pain. The certainty of the evidence ranged from moderate to very low. CONCLUSION: S-PIP provides modest early analgesic benefits after cardiac surgery. Further high-quality multicenter trials are required to clarify its overall clinical value.