Influence of barbed suture on leak pressures after double-layer inverting closure of cystotomy sites in sheep

Objective: To determine the influence of barbed suture on double-layer inverting closure of cystotomy sites in sheep. Study design: Ex vivo study. Sample population: Urinary bladders harvested from ovine (n = 26) cadaveric specimens. Methods: After collection and specimen preparation, a 3-cm-long incision was created on the ventral aspect of the urinary bladder. The cystotomy was repaired with barbed (n = 13) or nonbarbed analogous monofilament absorbable suture (n = 13) in a double-layer inverting suture pattern. Time required for closure in seconds was recorded for each test. Each bladder was connected to a pressure transducer to monitor intraluminal pressure during infusion with dyed Hartmann's solution until leakage occurred. Intraluminal pressure at time of initial leakage and leakage site were also recorded. Two-sample t tests were used to compare initial leakage pressure and closure time between the 2 types of suture (P =.05). Results: The mean (± SD) leakage pressure of ovine urinary bladder incisions did not differ between closures with barbed sutures (42.3 ± 21.7 mmHg) and nonbarbed closures (32.5 ± 14.4 mmHg, P =.187). Cystorrhaphies were performed faster with barbed suture (307 ± 50 seconds) than with nonbarbed suture (390 ± 62 seconds, P =.001). Conclusion: The use of barbed suture did not affect mean leakage pressure of ovine urinary bladder incisions but decreased the time required to complete cystorrhaphies in this model. Clinical significance: This study provides evidence to support the use of knotless barbed suture for open ovine cystorrhaphies. Use of such suture for laparoscopic and laparoscopic-assisted procedures in sheep warrants caution until cyclic and in vivo testing is performed with appropriate laparoscopic instrumentation.