The Effect of Laparoscopic Staplers On Small Bowel Perfusion and Leak Rates

Bilal M Shafi, MD, Parth K Shah, MD, Harveen Bal, MD, Douglas L Fraker, MD. Hospital of University of Pennsylvania

Introduction: Few studies have been designed to assess the performance of laparoscopic surgical staplers, especially when it comes to their contribution to leak. This study analyzes the effect of staples and staple height on tissue perfusion in an acute as well as chronic study. Methods: Staple lines created on live porcine small bowel segments using laparoscopic surgical staplers were tested for perfusion using visible light spectroscopy to assess tissue oxygenation. Previously reported perfusion measurements taken on both the serosal surface (SS) and mucosal surface (MS) of the staple lines are reported as percentage of oxygen saturation. Three separate experiments were performed comparing: (1) measurements at the staple line (n=24) and 4cm away (n=24) ; (2) staple height: white (2.5mm, n=9), blue (3.5mm, n=9), green (4.1mm, n=6) staple loads; and (3) position along the staple line in reference to the hinge of the stapler: proximal (n=8), mid (n=8), and distal (n=8). We continue to collect data in the acute study. In addition to this a set of animals will be survived for a period of 1, 3, and 6 weeks to evaluate perfusion and histology with various staple heights. Data are reported as means; parametric tests were used for analysis. Results: Preliminary data suggests tissue perfusion was significantly reduced at the staple line (SS – 63%, MS – 25% ) when compared to measurements away from it (SS – 77%, MS – 41%) (p<0.001). Perfusion was also related to staple height on both the SS and MS; white loads had the worst profile (SS – 57%, MS – 18%) when compared to blue (SS – 65%, MS – 28%) (SS -p<0.07, MS – p < 0.1) and an even worse profile when compared to green (SS – 70%, MS – 32%) (SS – p<0.01, MS – p < 0.08). The proximal end (MS – 34%) of all staple lines showed a trend of improved perfusion when compared to the mid portion (MS – 23%) and the distal end (MS – 17%) on the MS. No difference was seen on the SS. We are continuing to collect data to increase the power in the acute study and will correlate this data to the chronic study. Conclusions: Laparoscopic surgical stapling significantly impacts tissue perfusion in small bowel. Previously presented data indicates, staple height is an important determinant of tissue perfusion where decreasing staple height leads to decreased tissue perfusion. This effect is seen more so on the serosal side than on the mucosal side of the staple line. Within the same staple line there is a trend toward decreased perfusion when moving distally along the staple line away from the hinge of the stapler. At the completion of this study, we continue to validate ths preliminary data and will correlate it with long term data on tissue perfusion and histology giving some insight into leaks.

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