Prospective clinical trial of factors predicting the early development of incisional hernia after midline laparotomy.

BACKGROUND: Information-based scoring systems predictive of outcomes of midline laparotomy are needed; these systems can support surgical decisions with the aim of improving patient outcomes and quality of life, and reducing the risk of secondary surgical procedures. STUDY
DESIGN: All study subjects were followed for a minimum of 6 months after operation. Numerous demographic, clinical, treatment, and outcomes-related perioperative factors were recorded to determine statistical association with the primary end point: incisional hernia development. The first analysis was designed to establish the statistical model (scoring system) for estimating the risk of incisional hernia within 6 months of midline laparotomy. Univariate and multivariate analyses were performed. A simple additive model was constructed using stepwise logistic and linear regression. The second part of the study analysis was validation of the scoring systems developed initially.
RESULTS: A logistic linear minimum regression model was developed based on four covariates independently predictive of incisional hernia: Body mass index (BMI) > 24.4kg/m(2); fascial suture to incision ratio (SIR) < 4.2; deep surgical site, deep space, or organ infection (SSI); and time to suture removal or complete epithelialization >16 days (TIME). The hernia risk scoring system equation [p(%) = 32(SIR) + 30(SSI) + 9(TIME) + 2(BMI)] provided accurate estimates of incisional hernia according to stratified risk groups based on total score: low (0 to 5 points), 1.0%; moderate (6 to 15 points), 9.7%; increased (16 to 50 points), 30.2%; and markedly increased (>50 points), 73.1%.
CONCLUSIONS: A statistically valid, straightforward, and clinically useful predictive model was developed for estimating the risk of incisional hernia within 6 months of midline laparotomy. Prospective independent validation of this model appears indicated.