Surgical Stapling of the Small Intestine

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SURGICAL STAPLING

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SURGICAL STAPLING OF THE SMALL INTESTINE Sharon L. Ullman, DVM, MS

Intestinal resection and anastomosis, bypass enterostomy, and typhlectomy are indicated for many intestinal disorders. The thoracoabdominal (TA, United States Surgical Corporation [USSC], Norwalk, CT), gastrointestinal anastomosis (GIA, USSC), and end-to-end anastomosis (EEA, USSC) stapling instruments all may be used to perform a variety of small intestinal surgical procedures.

INTESTINAL ANASTOMOSIS

Three stapled anastomosis techniques are available: the everting triangulating end-to-end anastomosis, the inverting end-to-end anastomosis, and the antiperistaltic side-to-side ("functional end-to-end") anastomosis. The latter is the procedure of choice owing to limitations of both of the true end-to-end anastomosis techniques. There are several methods of performing side-to-side enteroanastomoses, including the open lumina technique, functinal end-to-end anastomosis, offset method,. and one-stage functional end-to-end anastomosis and resection. As discussed in the following sections, the open lumina technique is the procedure most frequently performed in veterinary medicine owing to its low incidence of complications and ease of application.

From Veterinary Surgical Associates, Concord, California

VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE VOLUME 24 • NUMBER 2 • MARCH 1994

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True Anastomosis Techniques Triangulating End-to-End Anastomosis

Surgical Technique. 19• 21 The TA 30 stapling instrument is applied three times in a triangulation fashion to create this everting anastomosis. Stay sutures are placed to afford traction, appose mucosal edges of the bowel ends, and properly align mesenteric borders (Fig. lA). Allis tissue forceps may be used between traction sutures to approximate tissue edges (Fig. lB). The TA 30 instrument is locked in between two stay sutures and fired, creating a double row of staggered staples; the cartridge edge is used as a cutting edge to trim excess tissue to an appropriate length (Fig. lC). It is imperative that with the second and third application of the TA 30, previous staple lines are overlapped to avoid leakage (Fig. lD and lE). Comments. This anastomotic technique is rarely used because of its many limitations. This procedure is only appropriate for portions of the small intestine that are easily rotated. There is a potential to compromise the intestinal lumen after three applications of the TA 30 instrument. 21 Compared to other techniques, everting anastomoses have been shown to have delayed healing, increased incidence of adhesions, and leakage in the absence of omentum. 10• 15 When everted staple lines were compared to everted sutured lines, the latter had a significantly higher dehiscence rate. 8 Inverting End-to-End Anastomosis

Surgical Technique. 19• 21 The inverting end-to-end anastomosis is created using the EEA (USSC) instrument. After sizing instruments have been used to determine the appropriate size stapler to be used, a pursestring instrument is used at both cut bowel ends to prepare these ends for application of the EEA (Fig. 2A). A suitably sized EEA stapler is introduced into one segment of bowel through a separate longitudinal enterotomy site (Fig. 2B). The stapling device is advanced to the level of one pursestring. The EEA is then opened and the pursestring tightened. The anvil is introduced into the other bowel segment (Fig. 2B), and the second pursestring is tightened. The instrument is then closed and fired, creating an inverting anastomosis of two circular rows of staggered staples. Once the EEA is removed, the enterotomy site made to accommodate the EEA is closed using a TA device in a transverse manner to avoid compromise to lumen diameter (Fig. 2C). Comments. One drawback of this technique is the need to create an enterotomy incision to permit introduction of the EEA stapler. The two major limitations of this technique for enteroanastomosis are the sizes of EEA available and the potential for lumen compromise or stricture for-

Figure 1. Triangulating end-to-end anastomosis. A, Three everting traction sutures are placed to approximate transected bowel ends mucosa to mucosa, being sure to align mesenteric borders. 8 , The TA 30 instrument is placed just below the first two traction sutures. C, The instrument is fired. Using the cartridge edge as a guide, excess tissue is excised, leaving the traction sutures intact. D, The bowel is rotated and the procedure is repeated ; the second TA 30 placement must overlap the end of the previously placed staple line. E, The bowel is again rotated, and the third staple line is fired . F, Completed everted end-toend anastomosis.(© 1974, 1980, 1988, United Staies Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

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Figure 2. Inverting end-to-end anastomosis. A, The pursestring instrument is used on each transected bowel end in preparation. B, The EEA instrument is advanced through a longitudinal enterotomy to the anastomosis site. The proximal pursestring is tightened around the instrument, and the anvil is introduced into the distal bowel loop. C, The stapler is fired , creating an inverted anastomosis. The enterotomy site is closed with a T A stapling device in a transverse manner. (© 1974, 1980, 1988, United States Surgical Corporation . All rights reserved. Reprinted with permission of United States Surgical Corporation.)

mation. 21 In the majority of cats and small dogs, unless both portions of the small intestine chosen to form the anastomosis are greatly dilated, they will be too small to accommodate the EEA stapling device. Because this creates an inverting anastomosis, lumen diameter can be compromised.9· 21 • 24 When inverting stapled and hand-sewn anastomoses were compared in canine colonic anastomosis, there was a higher incidence of stenosis at the stapled colonic anastomotic site. 9 Interestingly, the development of strictures after stapled anastomoses was related to, among other factors, the exclusion of intestinal contents at the anastomotic site.24 Because these two studies were performed on canine colons, the incidence of strictures in small intestinal anastomoses can only be speculated. It should be remembered that EEA staplers should not be used on any tissue that compressed to less than 2 mm in thickness. If bowel is greatly dilated, this may be a problem.

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Side-to-Side Anastomosis Techniques

Functional rather than true end-to-end anastomosis techniques are preferred because they are easily performed and do not compromise gastrointestinal function of anastomotic lumen size. Techniques described include the open lumina technique, functional end-to-end anastomosis, and one-stage functional end-to-end anastomosis and resection. All three procedures anatomically create an antiperistaltic side-to-side anastomosis. The intestinal lumen sizes are larger than the original bowel lumen, whereas there is a viable decrease in stomal size with either of the true end-to-end anastomotic techniques.21 ' 22 Another advantage of functional end-to-end enteroanastomosis techniques is that they can be used to connect bowel ends with disparate diameters.Z1' 22 The length of the GIA 50 staple line (USSC) ultimately determines the size of the stoma in the completed anastomosis. This procedure can easily accommodate even large differences of lumen diameter, as often occur with intestinal obstruction and pre-obstruction dilatation. Open Lumina Technique

Surgical Technique.5' 19' 21 ' 22 After intestinal resection, one limb of the GIA stapling instrument is inserted to the designated cartridge length into each open intestinal lumen (Fig. 3A). The antimesenteric surfaces of the two bowel segments are apposed, and the stapler is locked and fired, creating two double staggered staple lines to join the bowel (Fig. 3B). Simultaneously, the knife blade cuts between these double staple lines to create a stoma. The GIA 50 is withdrawn, and the anastomotic staple lines are inspected for adequate hemostasis. Stay sutures are placed to include serosal and mucosal surfaces at the edge of the single opening that has been created (Fig. 3C). A TA 55 is used to complete the anastomosis (Fig. 3D). The stapler is applied across the intestinal edges, the jaws closed, and the instrument activated. Excess tissue is trimmed using the cartridge edge as a guide (Fig. 3D). An anchoring suture should be placed at the base ("crotch") of the GIA 50 staple line because this region, under the greatest tension, is most prone to staple pullout (Fig. 3E). Comments. The open lumina technique is the preferred method of creating a side-to-side anastomosis because only two staple cartridges are used instead of the four cartridges used with the closed technique. 19' 21 In a study of 20 dogs and 4 cats, surgical stapling equipment was used to perform open lumina enteroanastomoses.ZZ There was a low incidence of short-term complications (12.5%) consisting of postoperative anastomotic leakage in two dogs and a localized abscess at the staple line in one cat. No long-term complications were recorded in follow-up periods of 3 to 29 months. 22 The three animals with postoperative complications

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Figure 3. Open lumina anastomosis. A, The limbs of the GIA stapling instrument are inserted into the transacted bowel en.ds. B, Antimesenteric surfaces are approximated, and the stapler limbs are locked. The instrument is activated. C, The GIA instrument is removed; a single transverse opening remains.

were at higher risk for problems because of severe pre-existing peritonitis, a compromised immune system, or colonic involvement in the anastomosis.3· 7• 10 Although there is no data available comparing incidence of contamination between the open and closed techniques, intestinal content spillage was not a factor in a series of cases using the open lumina technique. 2 When performing any side-to-side enteroanastomosis, it is of major

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E Figure 3 (Continued). 0 , Traction sutures are used to approximate mucosal surfaces. The bowel is clamped with the T A stapling instrument. E, Completed open lumina anastomosis. The GIA staple lines are held apart by the direction of theTA staple lines. An anchor suture should be placed at the base of the anastomosis for additional security. (© 1974, 1980, 1988, United States Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

importance to be certain that all layers of bowel are incorporated into the TA staple line. All complications reported in the open lumina study occurred along the everted TA staple line. It was postulated that partial necrosis of the mucosa occurred, creating an environment that supported a leak or partial leak with abscess formation. Once the GIA 50 stapling instrument has been fired, the remaining stoma can be closed in two orientations. The anastomosis staple lines can be held apart by theTA staple lines (Fig. 3E), or the closure can be made so that the GIA staple lines are adjacent to one another; this technique is similar to the orientation of closure when the offset variation of the functional end-to-end (closed lumina) anastomosis technique is used (see Fig. 50). Some authors have been concerned about potential adhesions between anastomosis lines and the creation of a stricture; however, there are no known reports describing this complication in association with the open lumina technique. In the previously cited retrospective study of 24 open lumina intestinal anastomoses, both types of closures were used, and no strictures developed. 22

Functional End-to-End Anastomosis

Surgical Technique.19 • 21 This procedure is similar to the open lumina anastomosis; however, the bowel resection is performed using the GIA

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A

Figure 4. Functional end-to-end anastomosis. A, Bowel resection is performed with two applications of the GIA stapling instrument. B, The antimesenteric corner of the GIA staple line closure of both bowel loops is excised. C, Antimesenteric surfaces are aligned, and one fork of the GIA instrument is introduced into each bowel lumen. Illustration continued on opposite page

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Figure 4 (Continued). D, The GIA limbs are locked, and the instrument is fired. E, The common opening is closed with a TA 55 stapler. Traction sutures are used to ensure incorporation of all tissue layers with theTA 55 staple lines. F, Completed functional end-toend anastomosis. An anchor suture should be placed at the base of the anastomosis for additional security. (© 1974, 1980, 1988, United States Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

SO instrument. Two double staggered rows of staples are created, and the knife assembly simultaneously transects the bowel between the double staple lines (Fig. 4A). All bowel ends are closed during resection; the potential for contamination is diminished. The anastomosis is created with another application of the GIA 50. To accommodate the limbs of the GIA 50, the antimesenteric borders of the resection staple lines are excised (Fig. 4B). One fork of the GIA 50 instrument is introduced into each portion of bowel (Figs. 4C and 40); the instrument is locked and

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fired along the antimesenteric borders. An anastomotic stoma is created, as with the open lumina technique. The GIA 50 is withdrawn, and the staple lines are checked for hemostasis. Once again, traction sutures are placed to ensure mucosa-to-mucosa apposition and inclusion of all bowel layers in the closure (Fig. 4£). A TA 55 is used to complete the anastomosis in the same manner as described for the open lumina technique (Fig. 4F). An anchor suture is recommended at the base of the GIA anastomotic staple line for additional support, as this is the area of highest tension and mobility. Comments. The main difference between this technique and the open lumina is in the method of resection. This can be an advantage or a disadvantage, depending on one's perspective. It is advantageous to minimize the potential for contamination by closing all bowel ends during resection. This requires two additional GIA 50 instrument firings, however, which adds considerable expense to the procedure. As previously stated, open lumina enteroanastomoses do not appear to have a higher incidence of interoperative contamination;22 therefore, the use of two more GIA cartridges may not be justified. When closing the anastomosis, care must be taken to avoid direct apposition of the anastomotic (GIA) staple lines; this can create tissue thickness exceeding the limits that theTA 55 staples can accommodate. A leak can develop at the intersection of three double rows of staples.21 There must, however, be overlap of theTA 55 staple line and all previous staple lines (resection lines and anastomotic lines) to ensure a leakagefree closure (Fig. 4F). Tissues can easily slip as the TA staple line is closed; it is imperative that the proposed staple line be inspected prior to firing the TA 55 stapler to confirm all tissue layers extend beyond the cartridge edge. Offset Anastomosis

Surgical Technique.5 ' 19' 21 The only difference between this procedure and the functional end-to-end anastomosis is the orientation of the anastomotic staple lines to one another as the TA 55 is closed and fired. Once the GIA 50 is introduced, either the instrument is rotated 45° relative to the resection staple lines or the bowel is rotated around the stapler (Fig. SA), The result is the same; the GIA staple lines are not directly across from one another. Instead, they are "offset" by approximately 5 mm (Fig. SB). When the TA 55 is applied to complete the anastomosis, the anastomotic staple lines are held apart, and the stoma remains open (Fig. SC and SD). Comments. There has been a report of stricture formation from adherence of two anastomotic staple lines held in direct apposition when a functional end-to-end anastomosis was performed in humans. 16' 21 As

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B

Figure 5. Offset anastomosis. A, Initial steps are described in Figure 4A and 48. The GIA stapling instrument is rotated 45° relative to the transection staple lines, or the bowel is rotated and the instrument is held stable. Broken arrow indicates that the bowel walls slightly overlap. 8 , By rotating bowel or instrument, the staple lines created are not in direct apposition to one another when the remaining stoma is closed. There is a 5-mm space between inverted edges. C, A TA 30 or TA 55 stapler is used to close the common opening. Traction sutures are used to ensure incorporation of all tissue layers within the TA staple lines. 0, Completed offset anastomosis. Compare with Figure 4F. An anchor suture should be placed at the base of the anastomosis for additional security. (© 1974, 1980, 1988, United States Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

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Figure 6. See legend on opposite page

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stated before, to prevent potential leaks, the anastomotic lines should be slightly askew to prevent undue thickness of tissue at that site when the TA 55 is fired. The offset method prevents both excessive tissue thickness and adhesion formation. The offset variation is the method of choice if a closed lumina technique is chosen. One Stage Functional End-to-End Anastomosis and Resection

Surgical Technique. 15' 19 The portion of bowel to be resected is manipulated into a loop, and the antimesenteric borders of the proposed anastomotic site are apposed with a Babcock clamp. A clamp is placed at 60° angles across both loops of bowel at the intersection of viable and nonviable bowel (Fig. 6A). A scalpel blade is used to make a stab incision into each bowel lumen (Fig. 6B), through which the GIA forks are inserted (Fig·. 6C). The two prongs of the GIA are placed simultaneously into the proximal and distal loops with the instrument assembled. The GIA instrument is locked and activated, creating two double staggered rows of staples. Simultaneously, the knife assembly creates a stoma by cutting between the two double staple lines. A forceps is used to hold the anastomotic staple lines apart (Fig. 6D) as the TA 55 is positioned around both segments of bowel at the intended line of resection (Fig. 6D). The instrument is fired, creating a double row of staggered staples. The cartridge edge is used as a template, and the affected bowel segment is resected (Fig. 6E). An alternative to using theTA for the stomal closure and resection is to use a second firing of the GIA stapler. The advantage to using the GIA is that the stomal closure and resection are performed simultaneously, and the bowel removed is closed by the staple lines during resection, thus decreasing the chance of contamination. Both instruments create mucosal-to-mucosal closure. An anchor suture should be placed at the end of the GIA staple line to complete the procedure (Fig. 6F).

Figure 6. One-stage functional end-to-end anastomosis and resection. A, A Babcock clamp is used to appose antimesenteric borders, and a clamp is placed across both bowel segments at the intersection of viable and nonviable intestine. B, A stab incision is made into the lumen of both portions of bowel. C, One fork of the GIA stapling instrument is introduced into each bowel lumen, and the instrument is locked and fired. 0, The end of the GIA staple line is grasped with a forceps to hold the stoma open. The dotted line indicates appropriate placement of the T A instrument. E, A T A 55 is used to close the stoma. The edge of the T A 55 is used as a template to resect the nonviable bowel. F, Completed enteroenterostomy. An anchor suture should be placed at the base of the anastomosis for additional security. (© 1974, 1980, 1988, United States Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

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Comments. This procedure was performed on 10 dogs and resulted in no anastomotic leaks, intestinal obstruction, or wound infections. 15 This procedure uses only two staple cartridges and has minimal contamination potential. Because the two bowel loops are held in apposition, inserting the GIA stapler limbs and closing the instrument with the antimesenteric surfaces aligned is a less awkward maneuver than ·the other side-to-side anastomotic procedures. If the bowel tissue is thickened, there is a potential for exceeding the maximum allowance for tissue thickness that the staplers can accommodate when creating the second row of staples. In normal dogs, this was not a problem/ 5 but the possibility should be considered in animals with intestinal pathology. Bypass Enteroenterostomy

Surgical Technique. 19 Traction sutures are applied to align antimesenteric borders of the bowel loops to be joined in a side-to-side fashion. Using a scalpel blade, a stab incision is made into the lumen of each bowel segment (Fig. 7A), and the GIA limbs are inserted simultaneously into each lumen. The GIA is locked along the antimesenteric borders and discharged (Fig. 7B). Next, traction sutures are placed at the edge of each anastomotic staple line and distracted (Fig. 7C). This has the effect of holding the stoma open as well as approximating the wound edges mucosa to mucosa. The common opening is closed with a TA 55. The stapler is placed below the traction sutures and closed. Before activating the instrument, the intestinal edges are inspected to be certain that all layers of bowel are included. After the TA 55 is discharged, the cartridge edge is used as a template to trim excess tissue (Fig. 7D). The procedure is completed by placing an anchor suture at the base of the GIA anastomosis line for additional security (Fig. 7E). Comments. This procedure is similar to the one-stage functional end-to-end anastomosis except that there is no resection of bowel. Typhlectomy

Surgical Technique.6 The cecum is mobilized, and an appropriately sized TA instrument is chosen based on the width of the cecum at its base (Fig. 8A). The TA is locked and fired, creating a double row of staggered staples. The cecum is excised, using the cartridge edge as a cutting template. The TA is removed, and the staple line is inspected (Fig. 8B). Comments. Three clinical cases in which this technique was used were recently described. 6 There were no failures of the stapling equipment or postoperative complications involving the stapled typhlectomy site.

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Figure 7. Bypass enteroenterostomy. A, Traction sutures are used to approximate antimesenteric borders of the bowel to be anastomosed in a side-to-side fashion. Stab incisions are made into each bowel wall. 8 , One fork of the GIA stapler is inserted into each bowel lumen, and the instrument is locked onto the antimesenteric borders and fired. C, Traction sutures are used to hold the stoma open and approximate mucosal surfaces. 0 , The bowel is clamped with theTA 55 instrument. The stapler is fired , and excess tissue is trimmed, using the cartridge edge as a cutting template. G, Completed enteroenterostomy. An anchor suture should be placed at the base of the anastomosis for additional security.(© 1974, 1980, 1988, United States Surgical Corporation. All rights reserved. Reprinted with permission of United States Surgical Corporation.)

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A Figure 8. Typhlectomy. A, TheTA stapling instrument is clamped at the base of the cecum and fired. The cecum is transected, using the staple cartridge as a guide. 8 , Completed typhlectomy.

GENERAL COMMENTS

The mortality and complication rates associated with surgical stapling instruments do not exceed rates for the same procedures performed by hand-suture techniques. 1• 13• 22 Complications associated with surgical stapling of the intestines occurring in the immediate postoperative period include mechanical failure, inadequate approximation of tissues, bleeding, and anastomotic leaks.5 • 13 Long-term complications reported with stapled intestines consist of adhesions, stricture formation, and stomal dysfunctions and altered bacterial flora and motility. 13· 21 Most complications can be prevented by careful surgical technique. Regardless of the intestinal stapling procedure performed, the surgeon should not substitute stapling instruments for proper surgical technique. Minimization of contamination and trauma, maintenance of adequate blood supply, tension-free staple lines, and incorporation of all intestinal layers in the staple lines are all essential to a successful outcome.5· 8• 18 As a general rule, intestinal tissues that are not healthy enough to suture should not be stapled.5· 8 Small intestine with questionable viability should be resected.18 To minimize mechanical errors, the surgeon must be familiar with the stapling instruments prior to using this equipment in the operating room. All staple lines should be carefully inspected for adequate

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hemostasis before continuing to the next step of the surgical procedureP The B-shape staple configuration that preserves blood supply also can allow hemorrhage at the staple lineP· 21 To reduce the incidence of inaccurate approximation of tissues, the positioning of the stapling instrument should be carefully assessed prior to firing the cartridges. All tissue layers must be included in each staple line. Prior to final closure, all staple lines should be checked for leakage with saline infusion.5 Although it has been recommended that oversewing or inverting the cut edge of everted staple lines is necessary in accordance with Lembert's principles of intestinal surgeryP the everted staple lines have not been shown to cause increased. complications in most animal patients.6· 13· 16 We do recommend using an omental or serosal patch in animals, especially those patients with a compromised immune system or bacterial peritonitis? Stapling techniques have been shown to be more rapid and as effective as hand-sutured intestinal procedures. 4• 10• 13· 16 Healing progresses at different rates for hand-sutured and stapled intestinal closures. A higher bursting pressure is achieved with staples during the lag phase of healing. 2· 12 The intestinal staple or suture lines are functionally weakest at the end of the lag phase and more prone to dehiscence.10 Sutured anastomoses result in a lower tensile strength than stapled anastomoses after 7 days.U Staple lines have superior wound strength during the critical first weeks2 as a result of healing by primary intention and minimal inflammatory response.2 Staples avoid vascular compromise yet provide adequate holding power. The small amount of tissue involved and the B-shape of the staples result in minimal inflammation and necrosis. 21 Complication rates for sutured and stapled anastomoses appear to be comparable. Prevalence of small intestinal dehiscence in dogs after sutured anastomoses or enterotomies has been reported to be 15.7%.1 Stapled anastomoses compare favorably with a complication rate of 12.5%.22 Mechanical stapling of the bowel offers advantages such as consistent spatial alignment and simultaneous placement of staples at identical tension.16· 20· 21 Decreased surgical time results in decreased anesthetic time,12 less tissue exposure/6 and a lower risk of peritoneal contamination.16 These benefits are particularly advantageous in critically ill patients. Stapling techniques for small intestinal surgical procedures are rapid and efficient and are recommended for a variety of disorders. •. . References 1. Allen DA, Smeak DD, Schertel ER: Prevalence of small intestinal dehiscence and associated clinical factors: A retrospective study of 121 dogs. J Am Anim Hosp Assoc 28:70, 1992 2. Ballantyne GH, Burke JB, Rogers G, et al: Accelerated wound healing with stapled enteric suture lines. Ann Surg 201:360, 1985

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3. Bucknall TE: Factors affecting healing. In Bucknall TE, Ellis H (eds): Wound Healing for Surgeons. London, Bailleire Tindal, 1984, pp 42-44 4. Chassin JL, Rifkind KM, Sussman B, et al: The stapled gastrointestinal tract anastomosis: Incidence of postoperative complications compared with the sutured anastomosi5. Ann Surg 188:689, 1978 5. Chassin JL, Rifkind KM, Turner JW: Errors and pitfalls in stapling gastrointestinal tract anastomoses. Surg Clin North Am 64:441, 1984 6. Clark GN, Pavletic MM: Typhlectomy in dogs using a stapling instrument. JAm Anim Hosp Assoc 28:511, 1992 7. Crowe DT: The serosal patch: Clinical uses in 12 animals. Vet Surg 13:29, 1984 8. Dunn DH, Buchwald H: Gastrointestinal anastomoses: Facts and fiction. In Najuraian JS, Delaney JP (eds): Gastrointestinal Surgery. Chicago, Yearbook, 1979, pp 681-699 9. Dziki AJ, Duncan MD, Harmon JW, et al: Advantages of handsewn over stapled bowel anastomosis. Dis Colon Rectum 34:6;442, 1991 10. Ellison GW: End-to-end anastomosis in the dog: A comparison of techniques. Compend Contin Educ Pract Vet 3:486, 1981 11. Hamilton JE: Reappraisal of open intestinal anastomoses. Ann Surg 165:917, 1967 12. Hess JL, McCurnin DM, Riley MG, et al: Pilot study for comparison of chromic catgut suture and mechanically applied staples in enteroanastomosis. JAm Anim Hosp Assoc 17:409, 1981 13. Latimer RG, Doane WA, McKittrick JE, et al: Automatic staple suturing for gastrointestinal surgery. Am J Surg 130:766, 1985 14. Ravitch MM: Observations on the healing of wounds of the intestines. Surgery 77:665, 1975 15. Ravitch MM, Ong TH, Gazzola L: A new precise and rapid technique of intestinal resection and anastomosis with staples. Surg Gynecol Obstet 139:6, 1974 16. Ravitch MM, Steichen FM: Techniques of staple suturing in the gastrointestinal tract. Ann Surg 175:815, 1972 17. Reiling RB, Reiling WA, Bernie WA, et al: Prospective controlled study of gastrointestinal stapled anastomosis. Am J Surg 139:147, 1980 18. Richardson DC: Intestinal surgery: A review. Compend Contin Educ Pract Vet 3:259, 1981 19. Stapling Techniques: General Surgery with Auto Suture instruments, ed 3. Norwalk, CT, United States Surgical Corporation, 1988, pp 82-153 20. Steichen FM: The use of staplers in anatomical side-to-side functional end-to-end enteroanastomosis. Surgery 64:948-953, 1968 21. Steichen FM, Ravitch MM: Stapling in Surgery. Chicago, Yearbook, 1984, pp 79-112, 173-219 22. Ullman SL, Pavletic MM, Clark GN: Open intestinal anastomosis with surgical stapling equipment in 24 dogs and cats. Vet Surg 20:385, 1991 23. Wassner JD, Yohair E, Heinlich HC: Complications associated with the use of gastrointestinal stapling devices. Surgery 82:393, 1977 24. Yamane T, Takahashi T, Okuaumi J, et al: Anastomotic stricture with the EEA stapler after colorectal operation in the dog. Surg Gynecol Obstet 174:41, 1992

Address reprint requests to Sharon L. Ullman, DVM, MS Veterinary Surgical Associates 1410 Monument Boulevard, Suite 108 Concord, CA 94520