Small Bowel Resection

Current Procedures: Surgery > Chapter 19. Small Bowel Resection > Indications Tumor. Ischemia or incarceration. Trauma or perforation. Fistula. Ulcer or bleeding. Obstruction. Stricture or Crohn's disease. Contraindications Absolute Poor blood supply to bowel ends (ie, radiation-injured bowel). Unclear bowel viability after a revascularization procedure. Both ends of the small bowel may be brought up to skin level as temporary ostomies if the distal small bowel is involved. A proximal small bowel ostomy will create a high-output fistula that is difficult to manage. Alternatively, both ends can be stapled closed and a plan made for a second-look laparotomy in 24–48 hours. In extreme situations (eg, acute mesenteric ischemia with gangrene extending from the ligament of Treitz to mid colon), the likelihood of survival is very small. This is an absolute contraindication to attempted resection and anastomosis. Inadequate tumor margins. If a tumor is unresectable, and small bowel obstruction is likely to occur, a side-to-side anastomosis in uninvolved bowel proximal and distal to the obstruction may be performed as a bypass procedure, leaving the tumor in situ. Relative Peritoneal sepsis. Hemodynamically precarious patient. Extensive Crohn's disease. Stricturoplasty should be considered to minimize the need for extensive resection and risk of short gut syndrome; 90 cm is the approximate shortest length of small bowel that might still support a viable oral nutrition program. Informed Consent Expected Benefits Relief of obstruction. Control of gastrointestinal hemorrhage. Treatment of gastrointestinal ischemia, necrosis, or perforation. Potential Risks Common complications include: Surgical site infection (either deep or superficial). Bleeding. Systemic complications of major surgery, including pneumonia, venous thromboembolism, and cardiovascular events. Small bowel obstruction, stricture, and need for further surgery are also potential risks of small bowel resection. Patients with extensive intra-abdominal sepsis or who are in a malnourished state are at increased risk for anastomotic leak and enteric fistula. Equipment Self-retaining retractors are useful to help provide adequate exposure and access. Gastrointestinal anastomosis (GIA) stapler or thoracoabdominal (TA) stapler, or both (depending on surgeon's preference for anastomotic technique). Patient Preparation Preoperative Evaluation CT scan. Small bowel follow-through versus small bowel enteroclysis. As indicated for bleeding: Esophagogastroduodenoscopy, push enteroscopy, or double balloon enteroscopy. Capsule endoscopy. Nuclear scan. Angiography. At the Time of the Procedure Nutritional status should be optimized preoperatively if possible. Treatment of systemic illness. Intravenous perioperative antibiotics. Nasogastric tube, in cases of obstruction. Patient Positioning The patient should be supine. The abdomen is usually entered through a midline incision. Procedure Hand-Sewn Anastomosis The abdomen is entered via a standard midline incision. A thorough four-quadrant examination should be performed, with lysis only of those adhesions necessary to gain access to the area of pathology. Figure 19–1: After the margins of resection have been determined (dotted line), electrocautery is used to score the mesentery to encompass only vessels and lymph nodes (if cancer operation) related to the section to be removed. The first step in resection is to make a window in the mesentery adjacent to the bowel that is free of blood vessels at the site of the planned margins. This can be done using gentle dissection with a right-angle or Coller clamp. Figure 19–2A,B: Creation of this window allows a GIA stapler to be passed through on either side of the segment of bowel to be divided (Figure 19–2A). Typically the blue load (3.8 mm) is used to divide the bowel, creating two staple lines and two ends (Figure 19–2B). After the bowel is divided, the mesentery can be divided using a combination of electrocautery for further dissection plus hemostats with free ties, suture ligatures, or a harmonic scalpel along the previously scored line. Figure 19–3: After applying atraumatic bowel clamps, the first (posterior) layer of 3-0 silk suture is placed in an interrupted fashion taking seromuscular bites. This is the Lembert stitch. Stay sutures on either end help keep the bowel ends oriented appropriately to facilitate accurate placement of stitches. Figure 19–4: The staple line is excised using the cut setting of the electrocautery device. A 2-cm area should be allowed at the edge of the bowel clamp for a two-layer anastomosis. Figure 19–5: The inner layer is started using a double-armed 3-0 absorbable (PDS or Vicryl) suture. Starting in the midpoint with a full-thickness bite, the suture is tied. Then with one arm, the posterior inner layer is closed by including full-thickness bites of mucosa, submucosa, and seromuscular tissue in continuous fashion. Care should be taken to avoid inverting too much mucosa, which would narrow the anastomosis. Instead, just enough mucosa (1–2 mm), approximately half the thickness of the other layers, should be taken. To reduce strangulation of tissues within the anastomosis, the posterior full-thickness sutures are often locked to prevent the purse-string effect. This is usually a matter of surgeon's preference. Figure 19–6: After the corner has been turned, a transition stitch from suturing inside the bowel to outside is taken to facilitate completion of the anterior layer. Typically a narrow full-thickness horizontal mattress suture is used to end up with the suture on the outside. This is repeated with the other arm of the continuous suture heading in the opposite direction. After the transition stitch is completed, the suture is set up to complete the anterior layer. A continuous Connell (horizontal mattress) stitch minimizes mucosal inversion and is another way to optimize luminal diameter. Continuing with the over-and-over stitch is acceptable as well. The other arm of the suture can meet in the middle and be tied down to complete the full circumference of the anastomosis. Figure 19–7: The outer anterior layer of interrupted seromuscular (Lembert) stitches can then be placed easily. Confirmation of a patent lumen can be made by gently pinching the thumb and first finger at the bowel anastomosis to verify that a patent lumen is present. Figure 19–8: The mesentery should then be closed with 3-0 interrupted or continuous silk sutures to prevent internal herniation. Figure 19–1 Figure 19–2A–B Figure 19–3 Figure 19–4 Figure 19–5 Figure 19–6 Figure 19–7 Figure 19–8 Stapled Anastomosis All staplers are sized 3.8 mm unless the bowel is thick, in which case a 4.8-mm stapler is used. Figure 19–9A-C: First, the two segments of the small bowel to be used for the anastomosis are positioned in antiparallel apposition. The bowel segments should be checked to ensure that no mesentery is trapped between them. Adjacent corners of the staple lines are cut off (Figure 19–9A) and a GIA-60 mm or GIA-80 mm cutting stapler is inserted, with one limb of the stapler in the distal small bowel and the other limb in the proximal small bowel segment (Figure 19–9B). The stapler is fired, which should make a connection with the length of the stapler between the two ends of the bowel, creating a side-to-side, functional, end-to-end anastomosis (Figure 19–9C). The staple line is inspected by eversion to identify any sites of bleeding. Small interrupted 4-0 silk sutures can be placed to control any bleeding, or, alternatively, very light and controlled application of electrocautery may suffice. Figure 19–10A, B: The resultant enteroenterotomy is then closed using a TA stapler. Firing of the stapler completes the anastomosis. The staple line is often inverted by placing an outer layer of 3-0 silk interrupted Lembert sutures. Figure 19–9A–C Figure 19–10A–B Postoperative Care Epidural analgesia can decrease the amount of postoperative pain and ileus. The nasogastric tube should be left in place until resolution of postoperative ileus with nasogastric output < 200 mL per 8-hour shift. Diet should be advanced slowly after the passage of flatus. Perioperative antibiotics can be discontinued postoperatively if there has been no intraoperative contamination. Parenteral nutrition should be considered if the patient was malnourished preoperatively, if delayed resumption of oral intake is anticipated, or if prolonged postoperative ileus is expected. Potential Complications Wound infection. Prolonged ileus. Mechanical obstruction. Anastomotic bleeding. Anastomotic leak. Enterocutaneous fistula. Pearls and Tips To determine adequacy of the blood supply, note the color of bowel ends and the presence of pulsatile flow in terminal arterial branches at bowel ends. Free up the bowel ends to ensure sufficient mobility to achieve a tension-free anastomosis. Accurate apposition of the layers of bowel is critical: submucosa to submucosa and seromuscular to seromuscular layers. There should be no fat, other tissues, or hematoma within the anastomosis. This can be a barrier to healing, and can increase the risk of leak. Clear no more than a 1-cm wide area of serosa for anastomosis to avoid devitalization. Avoid excessive force or tension when suturing the anastomosis to prevent strangulation and leak. Allow for some amount of postoperative edema. Avoid excessive manipulation of the bowel ends with forceps to prevent further injury and bruising. References Irvin TT, Goligher JC. Aetiology of disruption of intestinal anastomosis. Brit J Surg. 1973;60:461–464.[PubMed: 4715175] [Full Text] Ravitch MM, Steichen FM. Techniques of staple suturing in the gastrointestinal tract. Ann Surg. 1972;175:815–837.[PubMed: 4555242] [Full Text] Scott-Conner CE, ed. Chassin's Operative Strategy in General Surgery, 3rd ed. New York, NY: Springer; 2001. Souba WW, Fink MP, Jurkovich GJ, et al, eds. ACS Surgery: Principles and Practice. WebMD Professional Publishing; 2003.