Kathryn A Schlosser, Sean R Maloney, Tanushree Prasad, Paul D Colavita, Vedra A Augenstein, Brant T Heniford. Carolinas Medical Center
Aims: BMI and hernia defect size are strongly associated with outcomes after open ventral hernia repair (OVHR). The impact of abdominal subcutaneous fat (SQFV), intra-abdominal volume (IAV), hernia volume (HV), ratio of HV to intra-abdominal volume (HV:IAV, representing visceral eventration) is less clearly elucidated. This study examines the interaction of multiple markers of adiposity and hernia size in OVHR.
Methods: A prospective institutional database was queried for OVHR with preoperative CT scans (2007-2017). 3-D volumetric software was used to analyze hernia characteristics and abdominal adipose tissue distribution. Demographics, operative characteristics, and outcomes were evaluated. Given the high degree of multicollinearity between markers of hernia dimensions and adiposity distribution, a principal component analysis was performed to create new component variables (PC1, PC2) for multivariate analysis. Variables PC1 and PC2 included BMI, defect area, HV, IAV, SQFV, and HV:IAV.
Results: A total of 1,103 patients (58.1% female) had pre-OVHR CTs. Mean BMI was 33.4±7.5kg/m2, age 54.4±12.4yr, 30.9% had diabetes, 15.1% used tobacco, and 66.4% had recurrent hernias. Mean defect area was 146.7±133.2cm2, SQFV was 6768.6±3583.4cm3, IAV 4288±2804.2cm3, HV 936.1±1286.9cm3, and HV:IAV was 0.28±0.45. Mesh was used in 93.4% of repairs, component separation in 47.9%, 34.1% had concomitant panniculectomy, and 26.6% were contaminated. In univariate analysis BMI, SQFV, IAV, HV, defect area, and HV:IAV ratio were associated with readmission, complications of Clavien-Dindo grade ≥3 (CD≥3), and component separation (p≤0.03 all variables). BMI, defect area, and HV:IAV were associated with recurrence and increased length of stay (p≤0.05 all). After principal component analysis controlling for multicollinearity, PC1 consisted mostly of hernia dimensions, with HV demonstrating a 56% correlation, HV:IAV 46.2%, and defect area 43.2%. PC2 consisted of primarily SQV (66.0%) and BMI (56.6% correlation). Multivariate analysis was performed to control for potentially confounding factors including PC1, PC2, age, sex, diabetes, tobacco use, history of recurrent hernia, contamination, and mesh placement. PC1 was associated with increased length of stay (+0.93days,SE0.13,p<0.0001), reoperation (OR 1.17, CI1.06-1.29), readmission (OR1.19, CI 1.08-1.31), CD≥3 (OR1.34, CI1.22-1.48), wound complications (OR1.34, CI1.21-1.47), and performance of component separation (OR1.32, CI1.20-1.47). PC2 was associated with slightly decreased length of stay (-0.34days,SE0.16,p=0.04), increased readmission rate (OR1.14, CI1.01-1.28), and increased wound complications (OR1.24, CI1.1-1.39).
Conclusion: The impact of hernia dimensions and distribution of abdominal adiposity has a complex impact on OVHR outcomes. Hernia dimensions, including defect area, HV, and the ratio of HV:IAV, most significantly impact operative outcomes.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 94964
Program Number: S026
Presentation Session: Complex Abdominal Wall Hernia
Presentation Type: Podium