Predicting Midline Fascial Re-Approximation with Component Separation In Complex Ventral Hernias: Maximizing the Utility of Pre-Operative Computed Tomography

BACKGROUND:

Component separation techniques have allowed for midline fascial reapproximation in large midline ventral hernias.  In certain cases, however, fascial apposition is still not feasible resulting in a suboptimal bridged repair  Previous estimates on myofascial advancement is based on hernia location and does  not take into account variability between patients.     Examination of pre-operative computed tomography (CT) may provide insight into these variabilities and may allow for prediction of abdominal closure with component separation.

 METHODS:

An IRB-approved, retrospective review was conducted of all patients who underwent abdominal wall reconstruction from 2007-2010 with component separation techniques by the senior author (PB).  Pre-operative CT imaging was obtained for all patients and specific parameters were analyzed using image analysis software (Terarecon, Inc.). Student’s t-test and Fisher’s exact test were used for continuous and categorical variables, respectively. Logistic regression was utilized to predict ideal operative closure. Multivariate analyses were adjusted for age and gender.  The a priori p-value was set at p < 0.05.

 RESULTS:

54 patients met the study criteria and had pre-operative CT imaging available for analysis.  48 patients had fascial reapproximation achieved, while 6 patients had a bridged repair.  Age, gender, weight, and BMI were similar between groups (p>0.05).  Multiple variables were investigated.  Significant differences were seen between groups in 3 variables; transverse defect size, defect area, and percent abdominal wall defect. Average transverse hernia defect and hernia area resulting in a bridged repair was 19.8cm and 420cm² v. 10.4cm and 184.2cm² in defects able to achieve closure (p<0.05).  On analyzing the percent abdominal wall defect, bridged defects were found to be statistically higher than defects achieving closure (18.9% v. 10.6%; p<0.05).

CONCLUSIONS:

Predicting midline approximation following component separation techniques is critical as outcomes following bridging repair result in high recurrence rates.    Preoperative determination of abdominal wall defect ratios and hernia defect areas may represent a more accurate method to predict abdominal wall closure following component separation techniques.