Assessment of Urostomy Parastomal Herniation Forces Using Incisional Prevention Strategies with an Abdominal Fascia Model

BACKGROUND: Approximately 10 000 patients undergo cystectomy/ileal conduit annually in the USA, of whom over 70% subsequently develop a parastomal hernia (PSH). Still, no well-established “best” practice for stoma creation to prevent a PSH exists. OBJECTIVE: To measure the relationship between incision size/type/material and axial tension force (ATF) as a surrogate for herniation force, using several models to mimic abdominal fascia. DESIGN, SETTING, AND PARTICIPANTS: Abdominal fascia models included silicone membrane, ex vivo porcine, and embalmed human cadaveric fascia. A dynamometer pulled a Foley catheter (20 mm/min) with the balloon inflated to 125% incision (linear, cruciate, and circular) diameter using a motorized positioning system. The maximum ATF before herniation was recorded. The study was repeated in unused silicone/tissue for suture reinforcement. We evaluated silicone, ex vivo porcine, and human abdominal fascia. INTERVENTION: Incision sizes (1–3 cm) in 0.5-cm increments were evaluated in silicone. A 3-cm incision was used in porcine/human tissue. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: ATF for herniation was recorded/compared across incision types/sizes using Mann-Whitney U and Kruskal-Wallis tests as appropriate, with α = 0.05. RESULTS AND LIMITATIONS: Linear incision ATF was significantly greater than cruciate and circular incisions. A cruciate incision had significantly greater ATF than a circular incision. In cadaveric tissue, incisions were significantly greater for linear (34.5 ± 12.8 N) versus cruciate (15.3 ± 2.9 N, p = 0.004) and for cruciate versus circular (p = 0.023) incisions. Results were similar in ex vivo porcine fascia and silicone. Reinforcement with a suture significantly increased ATF in all materials/incision sizes/types. The ex vivo nature is this study’s main limitation. CONCLUSIONS: This study suggests that urostomy fascial incision type may influence ATF required for herniation. Linear incisions may be preferable. Urostomy reinforcement may significantly increase ATF required for a PSH. These data may help establish best practices for PSH risk reduction. PATIENT SUMMARY: The results of this study illustrate that urostomy fascia incision type may influence the force required to create a parastomal hernia. Linear incisions may be preferable.