Background
Ventral incisional hernias (VIH) develop in up to 20% of patients following abdominal surgery. No widely applicable pre-operative risk-assessment tool exists. We aim to develop and validate a risk-assessment tool to predict VIH following abdominal surgery.
Study Design
A prospective study of all patients undergoing abdominal surgery was conducted at a single institution from 2008-2010. Variables were defined in accordance with the National Surgical Quality Improvement Project. VIH was determined through clinical and radiographic evaluation. A multivariate Cox proportional hazard model was built from a development cohort (2008-2009) to identify predictors of VIH. The HERNIAscore was created by converting the hazards ratios (HR) to points. The predictive accuracy was assessed on the validation cohort (2010) using a receiver operator characteristic curve and calculating the area under the curve (AUC).
Results
Of 625 patients followed for a median of 41(0.3-64 months), 93(13.9%) developed a VIH. The training cohort (n=428, VIH=70,16.4%) identified four independent predictors: laparotomy (HR 4.77, 95%CI 2.61-8.70) or hand-assisted laparoscopy (HR=4.00, 95% CI 2.08-7.70), COPD (HR=2.35; 95%CI 1.44-3.83), and BMI≥25 (HR=1.74; 95% CI 1.04-2.91). Factors that were not predictive included age, gender, ASA score, albumin, immunosuppression, prior surgery, and suture material/technique. The predictive score had an AUC=0.77(95%CI0.68-0.86) using the validation cohort (n=197, VIH=23,11.6%). Using the HERNIAscore--HERNIAscore=4*Laparotomy+3*HAL+1*COPD+1* BMI≥25--three classes stratified the risk of VIH: Class I (0-3 points):5.2%, Class II (4-5 points):19.6%, and Class III (6 points):55.0%.
Conclusions
The HERNIAscore accurately identifies patients at increased risk for VIH. While external validation is needed, this provides a starting point to counsel patients and guide clinical decisions. Increasing the use of laparoscopy, weight-loss programs, community smoking prevention programs, and incisional reinforcement may help reduce rates of VIH.