Bertuglia, Andrea

Gandini, Marco

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MARCO GANDINI

ANDREA BERTUGLIA

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In Vitro Evaluation of an Inverted End‐to‐End Equine Jejunojejunal Anastomosis Using Skin Staples

Institutional Research Information System University of Turin

In Vitro Evaluation of an Inverted End-to-End Equine JejunojejunalAnastomosis Using Skin StaplesMARCO GANDINI, MedVet and ANDREA BERTUGLIA, MedVet, PhDObjective—To compare functional indices of end-to-end (EEA) jejunojejunal anastomosis usingskin staples in horses with a 2-layer inverting hand-sewn technique.Study Design—Experimental study.Sample Population—Jejunal segments from 8 fresh equine cadavers.Methods—For each bowel segment, 2 EEA anastomoses were created: one 2-layer hand-sewn andone 1-layer using skin staples. Time for anastomosis creation was recorded and compared. Lumendiameter of each anastomosis was measured on digital radiographs after intraluminal instillation ofcontrast medium and inflation of the jejunal segments to 14mm Hg. Anastomotic indices (a com-pensated measure of stoma diameter) and bursting pressure were determined.Results—EEA jejunal anastomosis using skin staples was significantly faster than use of a 2-layerhand-sewn technique. Anastomotic index, a measure of lumen size, was significantly larger with theskin-staple technique; however, the bursting pressure of stapled anastomoses was significantly lessthan for the hand-sewn technique, but the values were well above those reported for other anas-tomotic techniques.Conclusions—An anastomotic technique using skin staples was easy to learn and perform, effectiveand faster, and mechanically comparable with a hand-sewn 2-layer technique.Clinical Relevance—The staple technique could be beneficial in equine gastrointestinal surgery byreducing anastomosis time, although further in vivo studies are needed to establish clinical safety.r Copyright 2006 by The American College of Veterinary SurgeonsINTRODUCTIONANASTOMOSES USING skin staples were initiallyused by military surgeons to create a single layer,inverting, end-to-end (EEA) anastomosis for treatment ofintestinal gunshot injuries.1 Preliminary studies in pigsand clinical application in human patients have been re-ported.1–3 The method was easy to learn, safe, faster, andmechanically superior to conventional, inverting hand-sewn techniques. In dogs, a method for performing aneverted, single layer, jejunojejunal EEA stapling tech-nique resulted in a fast, safe, and mechanically compar-able anastomosis with a routine hand-sewn pattern.4Our purpose was to compare the functional indices ofEEA jejunojejunal anastomoses created using either skinstaples or a 2-layer hand-sewn inverting technique inequine jejunal specimens. We hypothesized that stapledanastomoses could be constructed more quickly, wouldhave a larger lumen, and would be as strong as suturedanastomoses. To test this, we constructed EEA anasto-moses in fresh jejunal specimens and measured anasto-motic construction time, luminal diameter, and burstingpressure, and evaluated failure mode.MATERIALS AND METHODSJejunal SpecimensJejunal segments were collected from 8 slaughtered horses.Segments were harvested at least 2m proximal to the ileocecalPresented as a poster at the 8th Equine Colic Research Symposium, Quebec City, August 2005.Address reprint requests to Marco Gandini, MedVet, Dipartimento di Patologia Animale, Facolta` di Medicina Veterinaria di Torino,Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy.E-mail: marco.gandini@unito.it.Submitted January 2006; Accepted April 2006From the Department of Animal Pathology, Faculty of Veterinary Medicine, University of Turin, Turin, Italy.r Copyright 2006 by The American College of Veterinary Surgeons0161-3499/06doi:10.1111/j.1532-950X.2006.00208.x678Veterinary Surgery35:678–682, 2006valve and transported and stored at room temperature in0.9% saline solution. Each segment was used within 4 hours ofdeath to create 2 EEA anastomosis types: a 1-layer invertinganastomosis using skin staples (Weck Visistats35R, staplesize 5.7  3.9mm; Weck Teleflex Medica, Research TrianglePark, NC; Fig 1) and a hand-sewn double-layer invertinganastomoses. All anastomoses were performed by 1 surgeon(M.G.).Surgical TechniqueAfter cutting the jejunum with scissors at  601 to themesenteric border, the mesentery was stripped 5mm backfrom the transected edges with a moistened sponge.Stapled Anastomosis. Three single inverting horizontalmattress seromuscular sutures (2-0 polyglactin 910) were in-serted into each end as stay sutures; 1 suture was inserted onthe mesenteric border and the other 2 sutures inserted so thatthere was approximately equidistant spacing between the 3sutures around the circumference. Traction applied to the staysutures produced slight inversion of the transected edges. Skinstaples were then inserted  1–2mm apart around the cir-cumference, applying minimal pressure to the bowel surface,to produce an inverted pattern. Approximately 50–70 stapleswere used for each anastomosis.Hand Sewn Anastomosis. A 2-layer inverting suturedanastomosis composed of a single continuous layer in themucosa oversewn with a continuous Cushing pattern in theseromuscular layer using 3 metric polyglactin 910 was used asa control. After alignment of the 2 segments with 2-stay su-tures inserted at the mesenteric and antimesenteric borders,the mucosal suture layer was interrupted half-way aroundthe circumference to reduce the purse-string effect. Likewise,the Cushing pattern was also interrupted once around thecircumference.Time (minutes) to complete each anastomosis was recordedfrom insertion of the first stay suture to the insertion of thelast suture or staple. After anastomosis completion, eachbowel segment was transected  15 cm proximal and distalto the anastomosis and stored in 0.9% saline at room tem-perature before testing. Mechanical testing was conducted onall specimens within 1 hour of completion of the anastomosis.Lumen Diameter and Anastomotic IndexBefore biomechanical testing, each jejunal segment wasrinsed with 0.9% saline solution. Then, the lumen was filledwith a saline solution containing 10% of barium sulfate cream113% (Prontobario esofago, Bracco s.p.a, Milano, Italy), for 1minute after which the fluid was milked out of the specimen.The segment ends were closed with plastic self-locking bandsand the lumen was filled with air to an intraluminal pressureof 14mm Hg. Specimens were radiographed with a digitalsystem (Agfa Mimosa Vips 1206, Agfa-Gevaert N.V/S.A 96,Munich, Germany) and lumen diameter at the anastomoticsite and at 2 sites each 5 cm distant from the anastomosis weremeasured on the radiographic images.To account for interindividual horse variation, an anasto-motic index was calculated with the formula: index¼ 2 anastomotic lumen diameter (cm)/(distal lumen diameter[cm]þproximal lumen diameter [cm]). This value is the ratio betweenthe lumen diameter at the anastomotic site and the mean lumendiameter of proximal and distal sites.Biomechanical TestingAnastomotic leakage was evaluated by specimen inflationwith air and subsequent immersion in a water tank. Burstingstrength was determined for all specimens using a modified gasinflation tank test. A metal cannula connected to a com-pressed air tank was inserted into the lumen at 1 end of thespecimen and a similar cannula inserted at the other end wasconnected to a calibrated mercury sphygmomanometer. Thespecimen was submerged in water, inflated with air at 1L/minuntil gas leaked from the bowel. Luminal pressures were con-tinuously measured and recorded by digital camera. Review ofrecordings allowed determination of the peak pressure at spe-cimen failure. Failure was confirmed by observation of gasbubbles leaking from the specimen and a decline in luminalpressure.Statistical AnalysisAnastomosis construction time and anastomotic indexfor the 2 anastomosis types were compared using a pairedFig 1. Anastomosis completed with skin staples. Staples mayappear closer than 1mm or farther apart because they wereapplied while the suture line was under tension, whereas thephotograph was taken with the bowel relaxed.679GANDINI AND BERTUGLIAStudent’s t-test. Bursting pressure values were compared be-tween techniques using a Wilcoxon’s matched pair test. Allstatistical analyses were performed with commercially avail-able software (Graphpad InStatsversion 3.05 for Windows95/NT, GraphPad Software, San Diego, CA) with significanceset at P  .05. Results are reported as mean  SEM.RESULTSHand-sewn anastomoses had more pronounced inver-sion whereas the stapled anastomosis had a more bulkyappearance. The mean ( SEM) completion time forstapled anastomosis (6.63  0.17 minutes) was significantlyfaster than for hand-sewn anastomosis (17.24  0.31minutes; Po.0001; Table 1). The mean anastomotic indexfor stapled anastomoses (0.77  0.01) was significantlyhigher than for the hand-sewn anastomosis (0.72 0.01;Po.0001). Only 1 stapled anastomosis leaked air aftercompletion; none of the hand-sewn anastomoses leakedafter completion.All but 1 hand-sewn anastomosis failed at the mesen-teric attachment, at sites distant from the anastomosis, ata mean pressure of 180.83 3mmHg. The specimen thatfailed at the anastomotic site leaked where the 2 contin-uous sutures merged in proximity to the antimesentericsite. The mean bursting pressure for stapled anastomoses(133.3 19.09mm Hg) was significantly lower than forthe sutured anastomosis (P¼ .0078). Two stapled anas-tomoses failed at mesenteric sites distant from the anas-tomosis (Fig 2), whereas the other specimens failed atdifferent locations within the anastomosis.After distension, serosal tears were associated witheach staple in all stapled anastomoses but were not as-sociated with specimen failure.DISCUSSIONWe found that an EEA jejunojejunal anastomosis cre-ated by use of skin staples could be performed morerapidly than a 2-layer hand-sewn anastomosis and hadless reduction in luminal diameter but lower burstingpressure. The recorded bursting pressures for both anas-tomosis types were markedly higher than intraluminalpressures recorded in horses with bowel distention.Hand-sewn anastomoses typically failed on the mesen-teric border in the intermesenteric space away from theanastomosis, whereas stapled anastomoses typicallyfailed between the anastomosed edges.Table 1. Summary Data for Construction Time, Bursting Pressure and Anastomotic Index for Hand sewn (HS) and Stapled (SS) Jejunal AnastomosesSpecimenConstruction Time(minutes) Bursting Pressure (mm Hg) Anastomotic IndexHS SS HS SS HS SS1 16.88 6.05 178 40 0.75 0.782 15.93 6.70 170 95 0.69 0.753 17.80 6.20 190 160 0.71 0.744 17.25 7.53 185 145 0.8 0.825 18.35 6.35 200 180 0.67 0.746 16.35 6.88 175 165 0.69 0.737 17.08 6.83 165 160 0.76 0.818 18.25 6.50 180 120 0.72 0.8Mean 17.24 6.63 180.38 133.13 0.72 0.77SD 0.86 0.47 11.20 46.44 0.04 0.04Fig 2. Failure in the intermesenteric region at a distant sitefrom anastomosis in 1 stapled specimen.680 STAPLED JEJUNOJEJUNAL ANASTOMOSIS IN HORSESJejunojejunal EEA anastomoses are commonly per-formed in equine intestinal surgery. One approach is a 2-layer inverting hand-sewn pattern, a technique that isdemanding in terms of surgical skills and time. Use ofconventional intestinal staplers in horses has been limitedby cost and the dimensions of available instruments. TheEEA stapling devices commonly used in humans andsmall animals have been used in ponies5 but cannot beused in adult horses because the dimensions are too smallcompared with horse luminal diameter.5,6 Linear thora-co-abdominal (TA) staplers have been used to constructeverting or inverting triangulated EEA anastomoses;however, both techniques have some disadvantages. Theeverted anastomosis leaves contaminated mucosa ex-posed to the abdominal cavity, whereas the invertingpattern is demanding in terms of skills and time.7,8 Lineargastrointestinal (GIA, gastrointesinal anastomosis, orILA, intestinal linear anastomosis) staple devices havebeen used successfully to create true side to side or func-tional EEA jejunojejunal anastomoses in horses,9,10 al-though their cost can be a limiting factor and their use isalso not without complications.11–13 Nevertheless, amajor advantage of intestinal stapling instruments is theprecision by which staples are applied that ensure an evendistribution thus reducing the chance of anastomoticleakage. With the use of skin staplers, even distribution, isa function of the surgeon’s skill, although placing the tipof the instrument against the previously placed staple canfacilitate achieving a standardized distance betweenstaples.The skin-staple technique that we describe was easy tolearn and perform. The single anastomoses that leakedair just after completion was the first performed. Subse-quent attention to stay suture positioning resulted in op-timal edge inversion and improved placement of the staysutures and staples resulted in an airtight seal at comple-tion. In an in vivo study in dogs,4 all stapled anastomosesleaked air after completion but did not leak ingesta orresult in postoperative complications. Some of ourstapled anastomoses were stronger than intact intestinalwall, and all accommodated intraluminal pressures high-er than those reported for other stapled anastomosis.14Failure of most anastomoses (stapled and hand sewn)occurred on the mesenteric border in the intermesentericspace at a site distant from the anastomosis, highlightingthe importance of the serosa as a force-resisting layer.After distension, serosal tears occurred in stapled anas-tomoses as reported for other 1-layer techniques15 butwere not associated with specimen failure.Exposed foreign material used to create anastomosesis of concern for potential adhesion formation. The like-lihood of adhesions to skin staples in the equine abdomenis unknown but could potentially be prevented withthe use of anti-adhesion membranes16,17 or surgicaltechniques.18 Complications directly related to skin stapleuse in the gastrointestinal tract have not been reported indogs,4,19 pigs,2,20,21 or humans.3 In vivo studies are need-ed to evaluate the abdominal response in horses. Staplemigration can occur after remodeling of the anastomosis.In dogs,19 8 months after skin-stapled closure of entero-tomies, one-third of the staples were no longer visible onabdominal radiographs. The staples had apparently mi-grated into the bowel lumen and been evacuated in feces.In a skin-stapled EEA anastomosis study in dogs,4 stapleswere completely covered by fibrous connective tissue at21 days.Disposable skin staplers are readily available and areproduced by several different manufacturers. Our prelim-inary testing indicated that regular size (5.7mm 3.9mm)staples were adequate for horses because they resulted in abetter approximation of the edges in an inverting EEAjejunojejunal anastomosis. Other staple sizes are nowavailable and may be better suited to this application.Hemorrhage from enterotomy sites may be of concern23 asskin staples do not provide hemostasis because of theirdesign. Thus, if used for anastomosis, it would be import-ant to ensure adequate hemostasis of the transected bowelends before stapling. Skin staples are cost-effective com-pared with intestinal stapling devices and the technique wedescribe reduces the amount of mucosa exposed comparedwith an everted EEA-stapled anastomosis technique.Seemingly, the main advantages of our method arespeed of construction and reduced bowel handling com-pared with traditional hand-sewn techniques, factors thatmay be beneficial in reducing postoperative morbidity.Care with adequate hemostasis of transected ends beforeanastomosis and precise positioning facilitated by staysuture placement will be important to prevent leakage.Based on our results, skin staple devices may be useful tocreate technically simple and rapid EEA anastomoses inequine jejunum, and clinical evaluation of the techniqueseems warranted.REFERENCES1. Howell GP, Morgans BT, Ryan JM, et al: Assessment of theuse of disposable skin staplers in bowel anastomoses toreduce laparotomy time in penetrating ballistic injury tothe abdomen. Ann R Coll Surg Engl 73:87–90, 19912. Edwards DP, Galbraith KA.: Colonic anastomosis in thepresence of fecal peritonitis using a disposable skin stapler.J Invest Surg 11:267–274, 19983. Fraser I: Intestinal anastomosis with a skin stapler: a safe andefficient method in humans. Br J Surg 81:665–667, 19944. Coolman BR, Ehrhart N, Pijanowski G, et al: Comparison ofskin staples with sutures for anastomosis of the small in-testine in dogs. Vet Surg 29:293–302, 2000681GANDINI AND BERTUGLIA5. Robertson-Smith RG, Adams SB: Evaluation of an end-to-end stapling instrument for anastomosis of the small in-testine in the pony. Vet Surg 16:99, 19876. Freeman DE: Surgery of the small intestine. Vet Clin NorthAm Equine Pract 13:261–301, 19977. Bristol DG, Cullen J: Use of a linear stapling device to con-struct an inverted, triangulated, end-to-end anastomosis ofthe equine jejunum. Cornell Vet 79:88–93, 19898. Sullins KE, Stashak T, Mero K: Evaluation of intestinalstaples for end-to-end anastomosis of the small intestine ofthe horse. Vet Surg 14:87–91, 19859. Baxter GM, Hunt RJ, Tyler D, et al: Sutured end-to-end andstapled side-to-side jejunal anastomosis in the horse. VetSurg 21:47–55, 199210. Coatney RW, Adams SB: Evaluation of a linear stapling in-strument for side-to-side anastomosis of small intestine inthe pony (abstract). Vet Surg 18:63, 198911. Latimer FG, Blackford JT, Valk N, et al: Closed one-stagefunctional end-to-end jejunojejunostomy in horses with useof linear stapling equipment. Vet Surg 27:17–28, 199812. Mackey VS, Pascoe JR, Peterson PR: A potential techniqueerror in stapled side-to-side anastomosis of the small in-testine of the horse. Vet Surg 16:189–192, 198713. Frankeny RL, Wilson DA, Messer NT, et al: Jejunal intus-susception: a complication of functional end-to-end stapledanastomosis in two ponies. Vet Surg 24:515–517, 199514. Bickers RJ, Blackford JT, Eiler H, et al: A comparison of themechanical strength of two stapled anastomosis techniquesfor equine small intestine. Vet Surg 31:104–110, 200215. Nieto JE, Snyder JR: Comparison of a single versus a doublelayer hand sewn end-to-end anastomosis in the jejunum ofhorses. Proceedings of the 8th International Equine ColicResearch Symposium, Quebec City, QC, Canada, 2005, pp192–19316. Fogle CA, Elce YE, Little D, et al. Association of sodiumcarboxymethylcellulose and a bioresorbable hyaluronate-carboxymethylcellulose membrane with postoperativefactors in horses with small intestinal surgery: 33 cases(2003–2004). Proceedings of the 8th International EquineColic Research Symposium, Quebec City, QC, Canada,2005, pp 179–18017. Gandini M, Bertuglia A: Mesenteric flap to prevent adhesionsafter small intestinal end to end anastomosis in thehorse. Proceedings of the 8th International Equine ColicResearch Symposium 2005, Quebec City, QC, Canada, pp94–9618. Dawson DL, Coil JA, Jadali M, et al: Use of skin staplersin experimental gastrointestinal injuries. J Trauma 32:204–209, 199219. Fackler ML, Breteu JPL, Sendowski ICP, et al: Perforatingwounds of the abdomen by the modern assault rifle.J Trauma (China) 6(Suppl): 192–199, 199020. Coolman B, Ehrart N, Marretta SM: Use of skin staples forrapid closure of gastrointestinal incisions in the treatmentof canine linear foreign bodies. J Am Anim Hosp Assoc36:542–547, 200021. Doyle AJ, Freeman DE, Rapp H, et al: Life-threateninghemorrhage from enterotomies and anastomosis in 7 hors-es. Vet Surg 32:553–558, 200322. Eggleston RB, Mueller E, Quandt JE, et al: Use of a hyal-uronate membrane for jejunal anastomosis in horses. Am JVet Res 62:1314–1319, 2001682 STAPLED JEJUNOJEJUNAL ANASTOMOSIS IN HORSES

In vitro evaluation of an inverted end-to-end equine jejunojejunal anastomosis using skin staples

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In vitro evaluation of an inverted end-to-end equine jejunojejunal anastomosis using skin staples

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