Comparative Study of Three Reinforcement Materials On an Endo Gia™ Reload with Tri-Staple™ Technology

*Andrew J Duffy, MD, **Dwight Bronson, MS, **Jennifer Diederich, MS, **Stephanie Marcucio, MPH, **Nadia Neave, **William Mulligan, ASEE, **Elizabeth Lalime, BS. *Yale University School of Medicine, New Haven, CT, **Covidien, North Haven, CT

INTRODUCTION:
Surgical stapling device technology continues to evolve. Many bariatric and colorectal surgeons use staple line reinforcement in an effort to reduce adverse events such as anastomotic leaks and bleeding. Most stapling devices were not designed with reinforcement products in mind. This study evaluates the performance of two commonly used staple line reinforcement products, W. L. Gore® SeamGuard (GS) and Synovis® PeriStrip™ Dry with Veritas (SV), versus the Covidien Duet TRS™ Reload with Tri-Staple™ Technology (CD). We hypothesize that CD will demonstrate equivalent performance to other staple line reinforcement products on a Tri-Staple™ reload.

METHODS AND PROCEDURES:
We performed multiple firings of 45mm and 60mm CD and Tri-Staple™ reloads with GS and SV in 9 canines. Comparisons were made among 45mm firings on small intestine and for 60mm firings on the stomach. Under stable hemodynamic conditions, we obtained bleeding scores at 30 seconds and 90 seconds after creation of the staple line and division of the tissue. Any bleeding along the staple line after 30 seconds was collected on blotting paper for an additional 60 seconds and weighed on a microbalance. The materials were tested for adherence to the stapler during insertion through a standard 12mm Versaport™ for both 45mm and 60mm length reloads. We also scored the retention during positioning on the bowel and across previously placed staple lines. Undercrimp measurements were obtained on all staple firings as a measure of staple formation. The location of the firings on the stomach and bowel were randomized among the staple line reinforcement materials on each animal. The differences between the observed and expected overall scores were analyzed via the Chi-square test. Where appropriate, a Kruskal-Wallis test comparing medians was also applied.

RESULTS:
All reinforcement products performed as expected with limited significant staple line bleeding. There was no correlation of staple line reinforcement type with tissue thickness and bleeding after staple line creation. No differences were seen in bleeding scores at 30 or 90 seconds, or cumulative bleeding measurements, among types of staple line reinforcement. SG demonstrated significantly more displacement on the stapler head, typically sliding against the insertion force, during introduction through the port for the 45mm and 60mm loads (p<0.01). Similar differences were noted regarding rotation of SG reinforcement on the stapler heads during positioning on the bowel and stomach (p=0.00). CD showed significantly less undercrimp in stomach firings versus SV and GS (p<0.001). SV demonstrated significantly more undercrimp on bowel firings (p<0.001) versus GS and CD.

CONCLUSIONS:
Staple line reinforcement materials performed well with Tri-Staple™ reloads, and provide effective and equivalent hemostasis. CD demonstrated significantly less staple malformation relative to SV and GS on stomach. Significant differences were noted in the adherence of the GS to the staple reload, relative to CD and SV, during both port insertion and stapler positioning. This is likely due to the design of the GS relative to the new Endo GIA™ Reload with Tri-Staple™ head design. The GS requires a redesign to stay reliably positioned on the stapler.