Ex Vivo Pneumostasis Evaluation of a Variable-Height Staple Design

Abstract

This study examined the effect of using a variable-height staple construct containing three rows of staples with heights of 3.0, 3.5, and 4.0 mm (staple leg length, medial to lateral) versus standard three-row single-height staplers (with staple heights of either 3.5 or 4.8 mm) for pneumostasis in healthy porcine and canine lung parenchyma to determine whether a single stapler that uses variable staple heights could perform as well as, or better than, existing single-height stapling devices. The work presented here used healthy animal tissues, in lieu of diseased tissue, which is extremely difficult to obtain and quantify. Briefly, fresh explanted porcine and canine trachea-lung blocs were used for all testing. Tissue thicknesses were measured with a custom-design spring-loaded caliper before stapling with control and test articles to ensure that the tissue was of "appropriate" thickness for the stapler size (staple height) selected (per manufacturer's instructions for use). All tissue measurements were comparable across each area of lung tested, and both test and control devices were fired into the same tissue thicknesses. After stapling, the lungs were submerged in water, insufflated, checked for air leaks at four discrete (increasing) pressures, and scored using a predetermined scale. Statistical analysis was performed for n = 26 (3.5-mm staples), n = 29 (4.8-mm staples), and n = 26 or 29 (paired to the standard group) for the variable-height stapler (3.0-, 3.5-, and 4.0-mm staples). The results demonstrated that the test article comprising three rows of variable-height staples provided comparable pneumostasis with the standard three-row single-height staplers (with staple heights of either 3.5 or 4.8 mm) under the test conditions described. A novel test article containing three rows of staples with heights of 3.0, 3.5, and 4.0 mm (variable-height stapler) showed promising results when compared with standard commercially available single-height staplers, performing as well as or better than the standard single-height staplers. This work demonstrates important first steps to proving equivalent device performance, which might facilitate the use of a variable-height stapler in place of multiple single-height staplers.