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Beginner’s guide to gastrointestinal surgery

There are many indications for gastrointestinal surgery, including neoplasia, mechanical obstruction, abnormal positioning or failure of motility

09 July 2020, at 7:40am

Gastrointestinal surgery is commonly performed in both first opinion and referral practices. There are a number of common indications for gastrointestinal surgery including neoplasia, mechanical obstruction (due to neoplasia, intussusception or a foreign body), abnormal positioning (eg gastric dilatation and volvulus) or failure of motility (eg megacolon). This article will focus on basic surgery, and specifically suturing, of the stomach and intestines.


The small and large intestines are accessed via a ventral celiotomy. Access to the rectum may require pelvic symphysiotomy or a perineal approach depending on the location of the lesion. The abdomen should be clipped from mid-thorax to the level of the pelvis and four quarter draping performed to allow room for an adequate length of celiotomy incision. Ease of surgical exploration is aided by the use of self-retaining abdominal retractors (such as Balfour retractors), suction and a Poole suction tip and good lighting.

The edges of your incision should be covered with moist laparotomy swabs prior to placement of your retractors. The precise order of exploration of the abdomen is up to the individual surgeon but should be consistent and ensure all structures are examined and palpated. With respect to the intestine, it makes sense to run the gut from either the proximal or distal end, paying attention to regional lymph nodes and gut wall thickness. Waves of peristalsis should be apparent during examination.

For all gastrointestinal surgeries consider changing gloves and kit if there has been contamination of these by intestinal contents or if there is a neoplastic aetiology.

If there has been spillage of intestinal contents, the abdomen should be lavaged prior to closure of the celiotomy.


  • Isolate the stomach from the surrounding viscera
  • Place stay sutures (using 3/0 or 4/0 USP monofilament suture material) either side of your proposed entry site on the ventral surface of the stomach in an avascular area of the fundus
  • Using an assistant to elevate the stay sutures (to limit spillage), use a number 11 blade to make a stab incision into the stomach lumen
  • The gastrotomy incision can then be extended using Metzenbaum scissors to create an appropriately sized incision
  • Remove the foreign body (Figure 1) or obtain a biopsy


The stomach can be closed in a single- or two-layer closure (the author usually performs a two-layer closure as the layering of the stomach wall is usually clearly visible) (Figure 2).


Indications: foreign body removal, full thickness biopsy

Once the location of the lesion has been identified, the affected loop of bowel should be isolated using moist swabs to reduce the risk of contamination. The lumen of the intestine orad and aborad to the lesion should be occluded to reduce the risk of leakage of intestinal contents. This can either be achieved using the fingers of an assistant or using atraumatic bowel clamps (Doyens).

Intestinal foreign body
FIGURE (3) Enterotomies are performed to remove intestinal foreign bodies. The dashed line indicates the location of the incision on the anti-mesenteric border within a viable area of intestine

Make your incision into a healthy-looking area of bowel (Figure 3) on the anti-mesenteric border using a number 11 blade ensuring the length of the incision is suitable for your needs (eg if for a foreign body removal, the incision should be long enough to permit removal without tearing the incision further). Have the assistant stretch the bowel out between their fingers as this will make it easier for you to suture.


The intestine is most commonly sutured using a full thickness simple continuous or simple interrupted pattern and swaged on suture material. One cadaveric study suggested avoiding the use of conventional cutting needles (Mitsou et al., 2018). It is not necessary to use inverting suture patterns nor to do a two-layer closure. Sutures should be placed 3 to 5mm from the edge of the tissue and around 3mm apart. Minimise how much you handle the edges of your tissue with forceps (Figure 4A) and use Debakey forceps rather than rat tooth forceps. The submucosa must be included in the closure.

The author prefers to use simple interrupted sutures of 4/0 USP polydioxanone in the small intestine (Figure 4B) unless the tissue is very thick (in which case 3/0 USP polydioxanone is used). Surgical sites should be wrapped with omentum after suturing. This can be tacked in place depending on personal preference.

Serosal patching can be utilised in cases where there are concerns regarding the strength of your repair if resection of the affected section of the intestine is not feasible.

Leak testing

The author usually performs a leak test of any intestinal incision as it allows for peace of mind. Saile et al. (2010) reported that for canine jejunum, saline volumes of 16.3 to 19ml (digital occlusion) and 12.1 to 14.8ml (Doyen occlusion) could be used to achieve intraluminal pressures of 34cm water during leak testing of a 10cm segment containing a closed biopsy site.

Bearing in mind we are not usually able to assess intraluminal pressures in surgery, the lumen of the intestine either side of the incision is occluded by an assistant’s fingers and 10ml of sterile saline introduced into the lumen using a 24 gauge needle (volume depending on the length of the bowel you are testing). The incision is checked visually for any signs of leakage and extra sutures placed as required.


Enterectomies are indicated for the removal of devitalised intestine, resection of neoplastic lesions (Figure 5A), management of intestinal wound dehiscence and irreducible intussusception (Figure 5B).

  • Isolate the affected segment of the bowel as previously advised
  • Determine the section of bowel to be removed based on either its vascularity, the length which is affected (eg intussusception) or, if neoplastic, an appropriate margin of grossly normal bowel
  • Ligate the individual arcade vessels supplying the affected segment of bowel to be removed using 4/0 USP monofilament suture material and then cut the mesenteric attachments of the segment of bowel to be removed (Figure 6)
  • Place two Doyen clamps either side of your site of resection (alternatively a crushing forceps can be applied to the end of the tissue which is to be removed) and use a number 11 blade to cut the tissue between the clamps
  • Bring the two Doyen clamps to lay close to each other so you can start to suture
  • The mesenteric border is the most common site for leakage from the anastomosis. The suture at the mesenteric border is therefore placed as a stay suture (some surgeons place the first three sutures at the mesenteric border as stay sutures) (Figure 7)
  • The anastomosis is performed using full thickness simple interrupted sutures of 4/0 USP polydioxanone sutures which should be placed 3 to 5mm from the edge of the tissue and around 3mm apart (Figure 8). You are aiming to appose serosa to serosa without mucosa everting through the suture line
  • A leak test is performed as above (using either Doyens or ideally an assistant’s fingers to occlude the lumen)
  • The mesentery is closed using 4/0 USP monofilament suture in a simple continuous pattern (ensuring you do not inadvertently include the vascular supply to the remaining intestine)
  • The surgical site is omentalised

Post-operative care

Nutrition is a significant consideration in the post-operative period and a plan should be in place for feeding before the surgery. Enteral intake of food is important both for nutrition of enterocytes (and thus wound healing) and also for stimulation of peristalsis. Thus, food should be offered at the earliest opportunity. Placement of a feeding tube (usually oesophagostomy or gastrostomy tube) should be considered at the time of surgery if the patient has been inappetant prior to surgery or you feel the patient may have specific requirements for feeding post-operatively (eg in septic peritonitis).

A full review of post-operative drug therapy is not in the scope of this article, but the most common time for intestinal incisional dehiscence, the most concerning complication seen after intestinal surgery, is reported to be three to five days post-operatively. Rectal temperature is usually monitored three times daily to check for pyrexia, and body weight can be monitored to assess for the accumulation of ascites, seen as an increase in body weight.

Complications of gastrointestinal surgery

  • Dehiscence of the surgical site resulting in septic peritonitis
  • Pancreatitis
  • Oesophagitis
  • Diarrhoea – particularly if the ileocolic junction is resected. This is better tolerated in cats than dogs
  • Ileus
  • Adhesions – uncommon in dogs and cats but can rarely cause issues with entrapment of organs
  • Short bowel syndrome has been reported with resection of between 50 and 80 percent of the small intestine
Author Year Title
Mitsou, K., Papazoglou, L. G., Savvas, I. and Tzimtzimis, E. 2018 Investigation of leakage holes created by four needle types used for closure of canine enterotomies. Open Veterinary Journal, 8, 411-414
Saile, K., Boothe, H. W. and Boothe, D. M. 2010 Saline volume necessary to achieve predetermined intraluminal pressures during leak testing of small intestinal biopsy sites in the dog. Veterinary Surgery, 39, 900-903

Rachel Hattersley, BVetMed(Hons), CertSAS, DECVS, MRCVS, graduated from the RVC and undertook a residency in small animal surgery at the University of Liverpool. She became a diplomate of the European College of Veterinary Surgery in 2012 and works at Dick White Referrals.

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