Thrombotic Effect of Purposeful Back-Wall Stitch for End-to-Side Microarterial Anastomosis in Rats

Abstract

The accidental placement of a back-wall stitch is a mistake easily made by microsurgeons during an end-to-side (ETS) anastomosis, which is technically more difficult compared with an end-to-end (ETE) anastomosis. The thrombogenic effects of a back-wall stitch may aggravate the already existing turbulence and therefore thrombus-prone ETS anastomosis. We investigated this dangerous combination by applying a purposeful back-wall stitch model (PBWS) in an ETS microarterial anastomosis model in various configurations the rat carotid and femoral arteries. We performed femoral and carotid artery bypass grafts via two ETS anastomosis. Carotid (n=28) and femoral (n=28) artery groups were equally divided into four different subgroups according to PBWS placement: Control (no PBWS) and 30-degree, 60-degree, and 90-degree subgroups with PBWS located at 30, 60, and 90 degrees, respectively. We found that there were no significant patency differences with respect to vessel type, PBWS placement, or time of assessment. The results of our current study and previous studies demonstrate that a PBWS in the ETS anastomosis does not have a major effect on thrombus formation. We think that an inadvertent back-wall stitch in the ETS anastomosis may not be a significant cause of thrombosis alone but in combination with retained thrombogenic material into lumen can contribute to thrombus.

Rat Microvascular Model is Tolerant to Technical Errors

“…This finding contradicts some past dedicated back-wall models. [8][9][10] Notably, we found arterial anastomoses with back-wall suture error are 59 times more likely to be thrombosed than to remain patent. In contrast, this OR rises astoundingly to 1,000 for venous anastomoses from our record.…”

“…Past literature often reported a high patency rate of up to 100% upon applying various technical errors, given the seeming discrepancy between experimental models and clinical practice. [3][4][5][6][7][8][9][10][11] In a microsurgery training setting, suture anastomosis is often the domain with the steepest learning curve, leading to patency failure ultimately when first beginning the training. A competent proficiency to reach anastomosis patency may take over 10 times of attempts and practice.…”

“…1,2 In-depth analyses of technical error types, including vessel torsion, large or uneven bites, back wall sutures, and others, have been shown to have varying differential effects on vessel patency in a rat model. [3][4][5][6][7][8][9][10][11] Such clinical errors are considered unacceptable in the clinical world due to the increased risk of vessel thrombosis. [12][13][14][15][16][17] However, the rat model exhibits a high tolerance to select technical errors.…”

A Comparison of the Minimal-Touch Technique and the Eversion Technique for Microvascular Anastomosis in a Rat Model

“…The result is an increase in turbulence near the vessel wall that has been shown to cause both immediate and delayedonset thrombosis in small caliber vessels. 15,16 Therefore, reducing the risk of an inadvertent back-wall stitch is a first-order priority in clinical microsurgery.…”

“…Back-wall stitches are known to be a common technical cause of thrombosis in microvascular anastomoses. 15,16 Gently grasping and everting the vessel wall with a microforceps, however, provides a direct field of view of the path of the needle and the back wall of the vessel (►Fig. 2A).…”