Comparison of the Effects of Full Median Sternotomy vs. Mini-Incision on Postoperative Pain in Cardiac Surgery: A Meta-Analysis

Introduction: It is not yet clear whether cardiac surgery by mini -incision (minimally invasive cardiac surgery [MICS]) is overall less painful than the conventional approach by full sternotomy (FS). A meta -analysis is necessary to investigate polled results on this topic. Methods: PubMed (R)/MEDLINE, Cochrane CENTRAL, Latin American and Caribbean Health Sciences Literature (or LILACS), and Scientific Electronic Library Online (or SciELO) were searched for all clinical trials, reported until 2022, comparing FS with MICS in coronary artery bypass grafting (CABG), mitral valve surgery (MVS), and aortic valve replacement (AVR), and postoperative pain outcome was analyzed. Main summary measures were the method of standardized mean differences (SMD) with a 95% confidence interval (CI) and P -values (considered statistically significant when < 0.05). Results: In AVR, the general estimate of postoperative pain effect favored MICS (SMD 0.87 [95% CI 0.04 to 1.71], P=0.04). However, in the sensitivity analysis, there was no difference between the groups (SMD 0.70 [95% CI-0.69 to 2.09], P=0.32). For MVS, it was not possible to perform a meta-analysis with the included studies, because they had different methodologies. In CABG, the general estimate of the effect of postoperative pain did not favor any of the approaches (SMD-0.40 [95% CI-1.07 to 0.26], P=0.23), which was confirmed by sensitivity analysis (SMD-0.02 [95% CI-0.71 to 0.67], P=0.95). Conclusion: MICS was not globally less painful than the FS approach. It seems that postoperative pain is more related to the degree of tissue retraction than to the size of the incision.