Validation of Urostomy Parastomal Herniation Incisional Prevention Strategies

Abstract

ObjectiveTo evaluate simulated parastomal herniation forces in in vitro abdominal fascial models. Our group previously illustrated how incision type may play a consequential role in bowel herniation force generated across an incision using several abdominal fascia models. We sought to 1)Confirm findings in fresh human tissue 2)Assess correlation between herniation force and incision size 3)Determine whether incision type impacts drainage in a simulated ex vivo ileal conduit. Materials and MethodsAxial tension force(N) of herniation was measured using our previously published protocol, pulling a Foley catheter balloon 3.8cm diameter affixed to a dynamometer through silicone/fascial incisions ranging 3cm-5.8cm. We simulated ileal conduits using bovine small intestine with stoma matured through human fascia using 3.0 cm linear or cruciate incisions. The conduit’s caudal end was catheterized and filled at 20mL/minute. Drainage was measured by pad weight change. Two-sided α<0.05 was used to reject the null hypothesis. ResultsMean(±SD) herniation forces in fresh human fascia varied significantly across linear longitudinal, linear transverse, and cruciate incisions (20.9±3.7, 23.3±8.8, and 8.9±3.8N, respectively[p=0.011]). Fresh human fascial linear incisions 3cm in diameter had a herniation force of 22.1±6.3 vs 3.5±0.7N for 5.8cm incisions when herniating a 3.8cm balloon(p=0.002). All observations were similar in silicone. In simulated ileal conduit, mean drainage: 70.8±3.6 vs 82.1±9.7mL (linear vs cruciate) after 100mL instilled, respectively(p=0.05). ConclusionsThis ex-vivo study further suggests incision type has predictable influence on herniation force. These data support standardization of urostomy construction techniques and evaluating the clinical impact of stomal maturation techniques on parastomal hernia rates.