Study selection and data retrieval
The search results are shown in the PRISMA diagram (Fig. 1). The initial screening identified 611 studies. Of these, 584 search results were excluded during the preliminary screening because they were unrelated or duplicated. The remaining 27 full-text manuscripts were retrieved, and a further 12 studies were excluded based on our inclusion and exclusion criteria. Fifteen studies evaluating four different regional anesthesia techniques were finally included for quantitative and qualitative analysis.16-30
The regional and local anesthesia techniques included the pecto-intercostal fascial (PIF), transversus thoracis muscle plane (TTMP), erector spinae plane (ESP), and pectoralis nerve (PECS) I blocks ( Fig. 2).
The 15 included studies were randomized to 849 patients. Of these, 405 patients were allocated to placebo or no intervention, 183 to the PIF block, 148 to the TTMP block, 93 to the ESP block, and 20 to the PECS I block.
According to the risk of bias evaluation, four studies had a low risk of bias, two had a high risk of bias, and some concerns arose with the remaining studies (Supplementary Material, File 2). The criteria that guided us in assigning the risk of bias judgments are available as supplementary material (Supplementary Material, File 3).