Subcutaneous and visceral adipose tissue in patients with primary and recurrent incisional hernia

PURPOSE: Visceral obesity rather than body mass index has been reported to be associated with a higher incidence of incisional hernias. The aim of this study was to examine the relationship between CT measured adipose tissue and muscle in primary and recurrent incisional hernia. METHODS: Patients with a ‘Primary’ or ‘Recurrent incisional hernia’ were obtained from a prospective cohort of patients who were being assessed for incisional hernia repair over a 2-year period. Computerised tomography (CT)-images were analysed using NIH Image-J software to quantify adipose tissue and skeletal muscle cross-sectional areas at the level of lumber vertebra 3/4 using standard Hounsfield units. To test inter-observer ‘absolute agreement’, each parameter was measured independently by two investigators and reliability analysis performed. RESULTS: Thirty-six patients were included in the study: 15 had a Primary while 21 had a Recurrent incisional hernia. Both groups had similar baseline characteristics. Reliability analysis for CT-measured areas showed very high interclass correlation coefficient (ICC) between observers. Patients in the recurrent group had significantly greater subcutaneous adipose tissue (SAT) [median = 321.9cm(2) vs 230.9cm(2), p = 0.04] and visceral adipose tissue (VAT) [median = 221.1cm(2) vs 146.8cm(2), p = 0.03] than those in the primary group. There was no difference in skeletal muscle areas for right [median = 2.8cm(2) vs 2.9cm(2)] and left [median = 3.7cm(2) vs 4.1cm(2)] rectus muscles between groups. CONCLUSION: Our study shows that patients with a recurrent incisional hernia have significantly more subcutaneous and visceral adipose tissue than those with a primary incisional hernia. Further studies in this area are required if we are to reduce the burden of recurrent hernia following repair of a primary incisional hernia.