Background
This investigation evaluated a novel three row variable height circular surgical stapler in sites with similar (colocolonic) and non-similar (gastrojejunic) thicknesses of apposed tissue, allowing interrogation of early anastomotic healing events.

Materials and methods
One gastrojejunostomy and two colocolostomies were made per subject utilizing a novel three row variable height circular stapler or a control DST SeriesTM EEATM; evaluations occurred at post-operative days 3, 10, 21 and 28 using select complementary interrogative methods including radiography, endoscopy, gross observations, tissue imaging/measurement and histopathology. Each anastomotic site was excised and anastomotic index was calculated; staple formation was also analyzed. Subject weight loss was also tracked.

Result
All animals survived the surgeries with no adverse events, and post-operative percent weight loss ranged from 0-13.8 %. Radiography provided insight to the location and number of staples per staple line. Fluoroscopy was beneficial when used in combination with the endoscope, allowing stoma visualization, verification of stoma patency and real time assessment of tissue health and healing. Anastomotic index calculations revealed similar results for both devices; notably, the novel device showed less relative contraction in the staple lines placed in the colon by Day 28. Histopathology results indicated adequate to excellent healing responses over the same time frame.

Conclusion
Based on the series of in vivo and post-mortem evaluation criteria presented here, the novel three row variable height yielded results comparable to the "gold standard" DST SeriesTM EEATM device in this model, which assessed tissue apposition at anastomoses with equivalent and non- equivalent tissue thicknesses.