This systematic review and meta-analysis was performed according to the Cochrane Handbook for Systematic Reviews of Interventions7 and follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)8 and Assessing the Methodological Quality of Systematic Reviews (AMSTAR 2) guidelines.9 The protocol for this systematic review was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO): CRD42018086635. The literature search, quality assessment, and data extraction and analysis, along with the critical appraisal, were performed by 2 independent researchers. Any disagreements occurring during the process, such as discrepancy between the assessment results provided by the 2 independent researchers, were discussed and resolved by the senior authors. The research question was formulated within the Patient Population, Intervention, Comparator, Outcomes, Timing, Setting (PICOTS) framework as follows:
(P) Population: Adults older than 18 years old undergoing surgery for LI;
(I) Intervention: LI with rod;
(C) Comparator: LI without rod;
(O) Outcomes: Stoma retraction rate;
(T) Time: 3 months postoperatively; and
(S) Setting: In- and outpatient.
Procedure. The PubMed, EMBASE, Cochrane Library, MEDLINE via Ovid, Cumulative Index of Nursing and Allied Health Literature, and Web of Science databases were systematically searched for randomized controlled trials (RCT) published in English from 1990 to the present using the MeSH terms ostomy, rod, and bridge combined with the Boolean operator AND and all synonyms combined with the Boolean operator OR. In addition, clinicaltrials.gov was searched for any ongoing studies. Relevant articles were identified and the results of the search were screened through the title, abstract, and/or full text article. The sensitivity of the search strategy was tested by screening the references of included articles for additional publications.
The articles included in this review compared creation of a LI with a rod to ileostomy without a rod in patients undergoing elective colorectal resections. Exclusion criteria were comparative observational studies, noncomparative descriptive studies, technical reports, studies involving pediatric populations, and studies comparing any of the interventions of interest to an irrelevant intervention, such as a skin bridge.
Ileostomy with a rod was defined as a LI matured over a supporting rigid plastic rod passed through a mesenteric window. Stoma retraction was defined as the disappearance of normal stomal protrusion to at, or below, skin level. The primary endpoint was stoma retraction rate.
Collected data included author, year of publication, study design, sample size, rates of postoperative adverse events, including the rates of stoma retraction, stoma necrosis, parastomal dermatitis, and parastomal hernia. Quality assessment of each individual study was performed according to the Cochrane Risk of Bias Tool7 on the following items: selection, performance, detection, attrition, selective reporting, and other bias risks. High risk of selection bias was defined as any situation negatively influencing random sequence generation and allocation concealment. Performance bias risk was high when patients and surgeons were not blinded. Not blinding outcomes assessors increases the risk of detection bias. Attrition bias risk was high when authors reported incomplete outcome data and reporting bias risk was present in cases of selective reporting. Levels of evidence of the included studies were defined according to the classification of the Oxford Center for Evidence-Based Medicine (CEBM).10
Data collection and analysis. The data from the included articles were collected to predefined Microsoft Excel (Excel 2010; Microsoft, Redmond, Washington) tables, and studies were assessed for external validity based on the above-mentioned quality assessment by 2 researchers independently.
Inverse variance and Mantel-Haenszel methods of meta-analysis were used for continuous and dichotomous variables, respectively. For continuous variables, the point estimate for standardized mean difference and standard error were calculated; odds ratios (OR) with 95% confidence intervals (CI) were calculated for dichotomous variables. Statistical heterogeneity among effect estimates was assessed using Cochran chi-squared and I2, and between-study variance was assessed using Tau2 statistic when the I2 was 50% or greater.9 A fixed-effects model was utilized for meta-analysis.
The results of the meta-analysis were illustrated on forest plots. The number needed to treat/harm (NNT) was calculated to assess clinical relevance of any statistical difference. Funnel plots (visual assessment of symmetry) and Egger’s tests were utilized to evaluate for publication bias. A P value <.05 was considered statistically significant. Statistical analysis was performed using RevMan (version 5.3; Nordic Cochrane Center, Cochrane Collaboration, Copenhagen, Denmark) and CMA Software, version 3 (Biostat, Englewood, New Jersey).