12 J. Brad Case and Gary W. Ellison The gastrointestinal (GI) tract follows the same basic healing curve as the skin but has accelerated healing properties. The lag or inflammatory phase of healing lasts 3 to 4 days. Immediately after wounding, contraction of blood vessels occurs, platelets aggregate, the coagulation mechanism is activated, and fibrin clots are deposited to control hemorrhage. The fibrin clot offers some minimal wound strength on the first postoperative day, but the main wound support during the lag phase of healing comes from the sutures.1 Enterocyte regeneration begins almost immediately after wounding; however, the epithelium offers little biomechanical support.1 The lag phase is the most critical period during visceral wound healing because most dehiscences take place within 72 to 96 hours after the wound has been created. Wound dehiscence of an intestinal wound (Figure 12.1) often leads to generalized bacterial peritonitis and subsequent death. Therefore, factors that negatively affect visceral healing are potentially of great clinical significance to the surgeon. Factors that cause intestinal wounds to leak include failure to adequately identify ischemic tissue; improper suturing or stapling technique; and factors that negatively affect wound healing such as sepsis, malnutrition, and antineoplastic therapy. The GI submucosa is composed primarily of dense type 1 collagen,2 which provides the majority of the tensile strength of the GI tract and is responsible for holding sutures after gastrotomy or enterotomy.1 Submucosal appositional closure of gastrotomy and enterotomy is preferred because inaccurate apposition causes eversion of mucosa, resulting in secondary healing, which is significantly delayed and increases the risk of leakage when compared to direct GI healing.1,3 Figure 12.1 Intraoperative image of an intestinal dehiscence in a dog with septic peritonitis 4 days after enterotomy for a linear foreign body. For a discussion of the important anatomic concerns with regard to GI laparoscopic procedures, please see Chapter 11. Careful consideration of the patient and the particular condition is required before performing laparoscopic GI surgery. The general considerations are discussed in Chapter 11. Although not defined specifically in veterinary surgery, the authors believe linear foreign bodies, septic peritonitis or previous peritonitis, intestinal adhesions (Figures 12.3 and 12.4), and large-diameter lesions to be potential contraindications to a laparoscopic approach.11 Linear foreign bodies cause plication and tethering of the bowel, which limit bowel exteriorization and may increase the risk of iatrogenic mesenteric perforation. Furthermore, linear foreign bodies are associated with a high rate (31%) of perforation and preexisting septic peritonitis,12 requiring careful exploration of the entire GI tract, and the accuracy of laparoscopic-assisted GI exploration is currently unknown. Adhesions have been noted to be a contraindication for laparoscopic GI surgery in humans.13,14 Large lesion diameter may also be a contraindication because exteriorization of affected bowel would require significant enlargement of the extraction incision, which might negate the benefits of the laparoscopic approach. A wide range of lesion diameters have been suggested by human GI laparoscopists, but more current guidelines suggest a maximal diameter of approximately 5 cm, although larger lesions are reported.15-17 Conversely, laparoscopic-assisted GI biopsy is an excellent alternative to an open approach in obtaining GI biopsies in conditions such as inflammatory bowel disease (IBD) and alimentary lymphoma in dogs and cats and is routinely performed in many centers. Figure 12.3 Intracorporeal view of a dog with small intestinal obstruction and multiple small intestinal adhesions. The laparoscopic-assisted approach was converted to an exploratory laparotomy after identification of the adhesions. Figure 12.4 Intraoperative image of the same dog from Figure 12.3. Notice the multiple adhesions and bunching of the bowel, which would have precluded extracorporealization via the extraction incision. Aside from the systemic health of the patient, a number of prognostic factors should be considered when performing laparoscopic-assisted enterotomy or enterectomy. Linear foreign bodies are associated with increased morbidity and mortality in dogs undergoing open enterotomy and enterectomy.17-19 Because a laparoscopic approach is more limited, identification of a linear foreign body should prompt the surgeon to perform or convert to an exploratory laparotomy. Nonlinear GI foreign bodies have recently been shown to be protective for postoperative dehiscence and septic peritonitis after open enterotomy and enterectomy.20 Clinically, dogs with nonlinear foreign bodies and intestinal mass lesions appear to have an excellent prognosis with laparoscopic-assisted enterotomy and enterectomy,11,21 although large-scale studies have not been performed. Preoperative septic peritonitis is associated with a greater risk of intestinal dehiscence after GI surgery.20,22,23 Furthermore, septic peritonitis results in cardiovascular and metabolic compromise of the patient, which may increase the risks of anesthesia. Increased length of anesthetic and surgical time may have deleterious consequences in some cases; thus, a laparoscopic approach may not be advisable. The clinical use of laparoscopic-assisted enterectomy or enterotomy in dogs and cats with preoperative septic peritonitis has not been reported. In human surgery, laparoscopy was found to be less accurate than exploratory celiotomy for penetrating abdominal injuries involving the stomach and small intestine, missing up to 19% of injuries in one study.24 Conversely, appendicular peritonitis is associated with an excellent prognosis when treated laparoscopically.25 For laparoscopic or laparoscopic-assisted gastrotomy, enterotomy, and enterectomy, the patient is positioned in a similar manner to when diagnostic procedures of the GI tract are performed; these are described in detail in Chapter 11. After establishment of a pneumoperitoneum, intracorporeal examination of the viscera is performed. Thereafter, pneumoperitoneum is discontinued, and either the stomach or intestine is exteriorized for gastrotomy, enterotomy, or enterectomy and anastomosis as indicated. Instruments needed include a straight laparoscopic Babcock forceps (required); straight or articulating DeBakey forceps (recommended); coaxial deviating laparoscopic Babcock forceps (optional if used with EndoCone; Karl Storz Endoscopy, Goleta, CA); a 5-mm, 30-degree laparoscope (required); blunt palpation probe (required) or fan retractor (facilitative); two threaded or smooth 5.5-mm cannulas (required for multiport technique); SILS (Covidien, Mansfield, MA) or EndoCone (required for a single-port approach); wound retractor (facilitative); baby Gelpi retractor (facilitative); biopsy instruments (required); basic surgical pack (required); and Thoraco-abdominal (e.g., TA, Covidien), Gastrointestinal Anastomotic (e.g., GIA, Covidien), or Endo-Gastrointestinal Anastomotic (e.g., EndoGIA, Covidien) staplers (required for stapled anastomosis). Laparoscopic gastrotomy for removal of gastric foreign bodies has been described in 20 clinical dogs.26 In this report, a midline, three-port technique was used, and the gastrotomy was closed in a single inverted pattern or with an endoscopic surgical stapler. Foreign bodies were removed using an endoscopic retrieval bag, and contamination was minimal. The clinical outcome was good in all dogs with no complications reported. Flexible endoscopy is successful for the removal of gastric foreign bodies in 90% of cases and is an ideal method for gastric foreign body removal in dogs.27 However, in some cases, flexible endoscopy has been ineffective, and a laparoscopic-assisted method can be used for rescue gastrotomy
Laparoscopic-Assisted Gastrotomy, Enterotomy, Enterectomy, and Anastomosis
Preoperative Considerations
Gastrointestinal Wound Healing
Diagnostic Workup
The general preoperative evaluation of dogs and cats undergoing laparoscopic-assisted GI surgery is similar to that of patients to be treated via laparotomy and is discussed in Chapter 11. However, it is important to consider advances in diagnostic imaging and specific characteristics of GI disease in patients being considered for a laparoscopic approach to better predict surgical success and to minimize frequency of conversion. In the past decade, significant improvements in diagnostic imaging have been made. For example, ultrasound and three-dimensional imaging modalities have become readily available in most referral institutions. Abdominal ultrasonography (AUS) allows for accurate assessment of bowel diameter and wall thickness4 and is also useful in documenting small volumes of peritoneal fluid and gas, loss of wall layering, and hyperechoic mesentery, which are findings consistent with peritonitis.5 However, given the limitations of AUS (e.g., inadequate operator experience, presence of large amounts of GI gas, and length of the exam),6,7 advanced diagnostics may be particularly useful in preoperative evaluation of patients being considered for laparoscopic-assisted GI surgery. Preoperative abdominal computed tomography (CT) is used commonly for evaluation of humans with abdominal and GI disease and is becoming more popular in veterinary patients.7-9 Contrast-enhanced CT is more accurate at lesion measurement versus AUS (Video Clip 12-1) and is reported to be 100% accurate in differentiating surgical from nonsurgical acute abdominal conditions in dogs.7 The authors of this chapter have found preoperative CT helpful in dogs and cats before laparoscopic-assisted GI surgery for a few reasons, including evaluation and measurement of intestinal lesions, location of lesions within the specific region of the GI tract, association with other abdominal structures, identification of adhesions, and exploration of the abdominal cavity before surgery (Figure 12.2). Accurate information regarding these parameters is helpful in predicting dogs and cats more likely to be amenable to a laparoscopic-assisted surgical approach. Abdominal CT may also be a useful diagnostic test for staging dogs and cats with alimentary neoplasia.10
Figure 12.2 Sagittal and frontal plane computed tomography (CT) images from a dog with an orad jejunal cloth foreign body. The exact location within the gastrointestinal tract and lesion size are easily assessed with preoperative CT. Abdominal ultrasonography was also performed in this patient, but acoustic shadowing complicated lesion localization and measurement (Video Clip 12-1). This dog was considered an excellent candidate for a laparoscopic-assisted approach based on the CT.
Patient Selection
Prognostic Factors
Patient Preparation
Patient Positioning, Port Positions, and Working Space
Surgical Techniques
Instrumentation
Laparoscopic and Laparoscopic-Assisted Gastrotomy
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