Experimental Study of Mechanical Integrity Testing in Stapled Large Bowel: Methylene Blue Leak Test Is Not Inferior to Air Leak Test

Abstract

<b><i>Background/Objectives:</i></b> Anastomotic leakage remains the most devastating postoperative complication in colorectal surgery. The mechanical integrity of the newly formed colorectal anastomosis can be evaluated by visual inspection intraoperatively; both air leak and liquid leak tests are also used to evaluate the integrity of stapled colorectal anastomoses. It is not clear whether double-stapled anastomoses are more prone to leaks than single-stapled anastomoses. The aim of our study was to compare the methylene blue and the air leak test in the experimental setting of single-stapled and double-stapled porcine bowels. <b><i>Methods:</i></b> Twenty-four distal colons were excised from slaughtered pigs without delay. The proximal bowel end was closed with a linear stapler using blue cartridges. The bowels were randomly divided into single-stapled or double-stapled groups. Air leak and methylene blue leak tests were performed. A digital pressure monitor with a gradual pressure increase function was used to both gradually increase pressure within the bowel and to determine the pressure at which the stapler line disintegrated. <b><i>Results:</i></b> Air leakage occurred at a mean pressure of 51.62 (±16.60) mm Hg and methylene blue leakage occurred at 46.54 (±16.78) mm Hg (<i>p</i> = 0.31). The air and methylene blue leaks occurred at comparable pressures in single-stapled bowels and in double-stapled bowels (47.21 [±14.02] mm Hg vs. 50.96 [±19.15] mm Hg, <i>p</i> = 0.6). <b><i>Conclusions:</i></b> The methylene blue solution leak test is not inferior to the air leak test. There is no significant difference in bursting pressure between single-stapled and double-stapled anastomoses.

Evaluating Performance of Circular Staplers Using Comparative Test Methods for Evidence-Based Surgery

“…For example, the variability of tests performed ex vivo with volume-controlled rather than pressure-controlled inflation led to a proposal of 30 or 34 mmHg 13,14 as an acceptable leak threshold. 24 The canine in vivo model more accurately recapitulates the challenging clinical environment of the staple line, including using pressure-controlled inflation to better account for the viscoelastic nature of the tissue 25,26 and specimen geometry. In these conditions, the threshold needed to be higher (≥40 mmHg) to reveal significant differences in the staple line integrity for the TriEEA and ECP staple lines (Table 1).…”

“…For example, the variability of tests performed ex vivo with volume-controlled rather than pressure-controlled inflation led to a proposal of 30 or 34 mmHg 13,14 as an acceptable leak threshold. 24 The canine in vivo model more accurately recapitulates the challenging clinical environment of the staple line, including using pressurecontrolled inflation to better account for the viscoelastic Red foam is affixed to custom fixturing which engages with a tensile tester and allows firing into the foam. The device is held to a pegboard using a vice and thermoplastic set to hold the contour of the device such that the distal end is vertical.…”

Dynamic Serosal Perfusion Assessment during Colorectal Resection Using Visible Light Spectroscopy

“…We routinely tested colorectal anastomoses with an air-leak test. If positive, the anastomosis was redone with or without defunctioning ileostomy at the surgeon’s discretion [15]. After surgery, clinical examinations were conducted on daily ward rounds, and diagnostic tests like computer tomography or endoscopy were carried out as necessary.…”

An alternative asymmetric figure-of-eight single-layer suture technique for bowel anastomosis in an in vitro porcine model

“…After anastomosis completion, the specimen was stored in normal saline solution at room temperature and tested within 1 h. The leakage testing was conducted essentially as described previously (23,(31)(32)(33)(34)(35)(36). Briefly, a 4-cm flexible pipe was tightly connected to a 50-ml syringe, which was inserted into the proximal end of the anastomosis.…”