Ureter, bladder, and bowel were examined for tissue injury after no compression, 1 sec, 10 sec, 30 sec, 1 min, and 5 min compression with a robotic grasper. Tissues were harvested either immediately after compression or after the animals were survived 10-14 days. A single pathologist graded the tissue crush injury in 4 categories (inflammation, nuclear smearing, necrosis, and hemorrhage) on a 0 – 5 point scale with 0 representing no change and 5 indicating severe change.
Results in the immediate period showed a trend towards increased injury to the bowel (p=0.07), but not in the ureter (p=0.16) or bladder (p=0.30). At the 14 day follow up, there were no differences in the injury scores between the tissue types or with the compression time with all categories of injury scoring 0.
The porcine model may be more difficult to prove injury to than in humans as evidenced by prior partial nephrectomy models, but this study demonstrates that short term grasping may not be as harmful as initially thought. Further studies that include grasping tissues for longer periods of time to induce ischemia are needed as well as the grasping of vascular structures.
Presented by Necia M. Pope, et al. at the American Urological Association (AUA) Annual Meeting - May 14 - 19, 2011 - Walter E. Washington Convention Center, Washington, DC USA
Reported for UroToday by Michael Louie, MD, Department of Urology, University of California, Irvine.