Enterotomies are routinely performed in dogs for various purposes, such as treatment of foreign body obstruction, biopsy specimen collection, or enteral feeding tube placement.1,2 Among dogs that undergo an enterotomy, incisional dehiscence with leakage of luminal contents can be a major contributor to morbidity and death, and rates of full-thickness dehiscence in dogs are reported to be 3% to 28%.3–7 Dehiscence may result in septic peritonitis, which is a surgical emergency associated with a guarded prognosis; among affected dogs, the mortality rate is 36.4% to 85%.8–10 Thus, minimizing intestinal incisional dehiscence and leakage following enterotomy is critical for improving long-term outcomes for dogs that undergo gastrointestinal tract surgery.
A variety of hand-sewn and staple techniques11,12 are routinely used for intestinal closure. Use of barbed suture materials for intestinal closure has previously been investigated in several experimental studies.13–16 In the production of barbed suture material, automated processing creates either unidirectional or bidirectional barbs; when the suture material is used, the barbs lodge within tissues, allowing even distribution of tension along the incisional line. The tensile pull strength of barbed suture materials is equivalent to that of barbless suture material of the same size or 1 size smaller (as defined by the US Pharmacopeia).16 In canine leak pressure studies,13,15 the ILPs for barbed suture material and smooth monofilament suture material appear equivalent. Unidirectional barbed sutures have a preconstructed end loop, and the suture needle can be passed through the loop after the initial tissue bite; hence, no knot is needed. Moreover, the barbs prevent backward slippage of the suture material. Overall, these characteristics of the suture material negate the need for knotting for suture security, which can facilitate shorter operative times.15 The elimination of suture knots may be advantageous because knots represent the weakest portions of a suture line.17
Leakage pressure testing is commonly performed to evaluate surgical methods that mimic in vivo conditions prior to clinical implementation.2,13,18–24 Cadaveric samples have been used for leak pressure testing of barbed suture materials in canine,13,15 equine,25 and ovine studies22,23; in those studies, various specimen storage temperatures and handling techniques prior to definitive testing were evaluated. Multiple factors, including but not limited to sample manipulation, storage temperature, interval from sample collection to time of testing, and postmortem changes associated with tissue autolysis, may adversely change and negatively affect the microscopic architecture and tissue integrity of tested specimens and, subsequently, affect study results and data interpretation.21 Results of a recent study21 identified the negative impact of cryopreservation and the deleterious effects of a single freeze-thaw cycle on the integrity of closed enterotomies in cadaveric jejunal specimens obtained from juvenile pigs. To date, there is no consensus regarding the optimal storage conditions for canine intestinal specimens prior to postenterotomy leakage pressure testing.
Following enterotomy closure in cadaveric intestinal specimens, establishment of a seal at the site of closure that is water-tight at physiologic pressures is a crucial step in determining the efficacy and safety of experimental suture materials and patterns for use in live animals. Small intestinal peristaltic pressures in healthy dogs range between 15 and 25 mm Hg.26 Determination of any potential negative effect of storage conditions on leakage pressures of cadaveric tissue specimens is of critical importance for validation of the results of ex vivo enterotomy leak pressure studies. This information may lead to implementation of more rigorous protocol stipulations in future leakage pressure studies involving cadaveric specimens.
The purpose of the study reported here was to compare the effect of presurgical storage conditions on enterotomy site leakage pressures, specifically intraluminal pressure at the time of enterotomy leakage (ie, ILP) and MIP, following enterotomy closure with unidirectional barbed suture material placed in a single-layer appositional continuous pattern in cadaveric canine jejunal segments. We hypothesized that ILP and MIP would be greater for segments tested immediately following collection and segments chilled at 4°C for 24 hours prior to testing, compared with findings for segments that had undergone a single controlled freeze-thaw cycle (ie, stored at −20°C for 7 days and thawed at 21°C for 6 hours) prior to testing.
The authors declare no conflict of interest related to this study, nor was any financial support received.
The authors thank Jon Hash for assistance with cadaver specimen collection. All surgical suture was provided by Covidien Inc, Mansfield, Mass.
Initial leakage pressure
Maximum intraluminal pressure
Euthasol, Virbac AH Inc, Fort Worth, Tex.
Vetivex Hartmann solution for injection, Dechra Veterinary Products, Overland Park, Kan.
Random number generator, Research Randomizer, Lancaster, Pa. Available at: www.randomizer.org. Accessed Sep 12, 2019.
Ziplock, SC Johnson & Son Inc, Racine, Wis.
Polyglyconate, V-Loc 180 absorbable wound closure device (V-20 needle), Covidien Animal Health, Mansfield, Mass.
Insyte, BD Vialon Material, Franklin Lakes, NJ.
Methylene blue, Kordon LLC, Hayward, Calif.
Lifeshield Primary Plumset, Hospira, Lake Forest, Ill.
Plum A+, Hospira, Lake Forest, Ill.
Logical, Smiths Medical, Dublin, Ohio.
Passport 2, Mindray North America, Mahwah, NJ.
Statistical software, Stata/SE, v.15.0, StataCorp, College Station, Tex.
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