Data Extraction and Analysis
A single reviewer performed all data extraction to ensure consistency across each study. The results were broadly divided into two categories: safety and efficacy. After performing a full-text review, the most frequently discussed variables pertaining to safety (i.e. rates of infection, bleeding events, and mortality) and efficacy (i.e. adhesion formation rate and standardized tenacity scores) served as the major focus for analysis. “Infection” corresponded to any mention of infectious processes related to superficial site infection, sternal wound infection, mediastinitis, or sepsis after insertion of the adhesion barrier. “Bleeding event” corresponded to any mention of blood loss events intra- or post-operatively. “Mortality” corresponded to any mention of death in patients receiving a barrier. “Adhesion formation” corresponded to any mention of post-operative adhesions identified either at re-operation or through imaging. “Standardized tenacity score” (TSS) corresponded to any mention of a scaled-method for reporting adhesion severity.11, 12 No universal grading scale exists, and the studies assessed ranged from 0-3 to 0-21 point scales. All scales included a value for no adhesions (largely “0”), and they then varied along a spectrum from mild to severe adhesions requiring blunt to sharp dissection. A TSS equation that standardized the reported tenacity score values was developed and is presented in Figure 1.
A separate reviewer performed all data analysis using Excel. The rates of infection, bleeding events, and mortality, were determined by calculating the mean number of events in the patients receiving adhesion barriers and the available control groups via Excel. The adhesion formation was determined by calculating the mean number of events in patients the patients with adhesion barriers that received re-operation(s) and the available control group patients that received re-operation(s) via Excel. The TSS was determined by using the equation described previously (see Figure 1) via Excel. Issues during either data extraction and/or analysis were resolved by a third reviewer.
RESULTS:
695 articles were identified through the initial database searches (Scopus: 558; PubMed 137) (see Figure 2). After removing duplicates, 632 articles were screened. 603 were excluded, and the remaining 29 full-text articles were assessed for eligibility. Four studies were then excluded (three for wrong study design and one for wrong language) with a remaining total of 25 for review (see Table 1). The risk of bias is presented in Figures 3 and 4. 21 out of 25 studies had high bias in blinding of paricipants and personnel, as well as in outcome assessment. 21 out of 25 studies also had high bias in allocation concealment (Figure 3). About 80% of the studies had low bias in selective reporting (Figure 4).