LAUSR

To examine whether the dimensions of the abdominal rectus muscle (ARM) affect the risk of developing parastomal hernia (PSH). The hypothesis is that a thinner anteroposterior (AP) dimension of the ARM predisposes for PSH. Retrospective cohort study of rectal cancer patients undergoing tumour resection and permanent colostomy creation in two Swedish healthcare regions during 2005–2017. Patients were identified from the nationwide Swedish Colorectal Cancer Registry. Measurements of ARM dimensions in the AP and latero-lateral (LL) planes were made on preoperative (before permanent colostomy creation) and postoperative (9–18 months post stoma creation) computerised tomography images. The ARM dimensions were analysed in a multivariate logistic regression model, considering known risk factors and potential confounders. Some 151 of the planned 200 patients have been included, of which 40% are female and 20% have a radiologically evident PSH at approximately one year postoperatively. Preliminary results from the multivariate model do not indicate that ARM thickness can predict the occurrence of PSH. Body mass index seems to be the only predictor in this material. The study is still including. Preliminary results indicate that ARM thickness is not an independent risk factor for PSH development. Supplementary results will be presented.