Various portions of the small intestine are resected for a variety of reasons. Emergency procedures involving interference with the blood supply by a strangulated hernia, a volvulus due to a fixed adhesion, mesenteric thrombosis, traumatic injuries, localized tumors, and regional enteritis are among the indications for small bowel resection. Occasionally it may be judicious to perform an enteroenterostomy in the presence of many adhesions or extensive regional ileitis in an effort to avoid further resection of the already shortened small bowel resulting from previous extensive resections.
The indications for operation control the time allotted for fluid, electrolyte, and blood replacement (see Plate 47). Constant gastric suction is instituted. An inlying catheter for drainage of the bladder is useful in monitoring the adequacy of urinary output in response to treatment. When the pulse is elevated and gangrenous intestine is suspected, plasma expanders or red cells may be administered. Intravenous antibiotics are given, and the patient is aggressively rehydrated using central venous pressure and urinary output as monitors.
The stomach should be on constant gastric suction, and the suction should be adequate to avoid the danger of aspiration of gastric contents. A cuffed endotracheal tube is advisable to seal off the trachea and avoid the possibility of aspiration pneumonia.
The patient is placed in a comfortable position with the operating table elevated at right angles to the working level of the surgeon. A modest reverse Trendelenburg position may be helpful in improving subsequent exposure as well as in the retraction of dilated small bowel.
The skin is prepared in the usual manner.
The incision is made in the general area of the suspected lesion. In the trauma patient, a long midline incision ensures adequate exposure for an extensive exploration. When an incarcerated hernia is likely to contain gangrenous intestine, some prefer to open the abdomen with an oblique incision above the groin in order to divide the viable bowel above the point of incarceration, lessening the chances of gross contamination when the hernial sac is opened. In the presence of previous scars, especially in the midline, a new incision may be judiciously made beyond the end or to one side in order to lessen the chance of injuring the underlying, probably tightly adherent small intestine.
A specimen of abdominal fluid is taken for culture and its color and odor evaluated as predictors of “dead intestine.” The release of restrictions by adhesions or a hernia sac is the first priority in the hope that a return of adequate blood supply will follow. When the viability of the intestine is questioned, the bowel may be placed in warm, moist gauze for some minutes. Procaine may be injected carefully into the mesentery to stimulate visible arterial pulsations. Obviously gangrenous small bowel should be promptly isolated with towels in order to minimize infection. In trauma patients, the small as well as the large intestine must be thoroughly inspected for possible injury, since protruding mucosa may temporarily block contamination. Injuries to the mesentery with hematoma formation require very careful evaluation. Multiple perforations with extensive mesenteric injury may make resection of a segment of small bowel a safer procedure than an attempt at multiple repairs of a segment. The possibility of another intraluminal cause of obstruction mandates evaluation of the small intestine beyond the point of intussusception or obstruction.
Non-crushing Scudder clamps are applied proximal to the planned point of division of the small bowel as well as distal to the area to be resected. This prevents gross contamination of the obstructed bowel while controlling the blood supply. The specimen is resected (Figure 1) after a thin straight clamp is applied obliquely to the intestinal wall with a free mesenteric serosal border of 1 cm or more. This leaves a clear serosal area for the application of the TL60 with 4.8-mm staples.
The cutting linear stapler (TLC 55) can be used to approximate the open two ends of the divided small bowel (Figure 2). After the bowel has been divided on the modest oblique plane with 1 cm of freed mesenteric border, the ends are aligned. This is accomplished by placing traction sutures at the mesenteric and antimesenteric borders (Figure 2). The antimesenteric border is approximated, and each of the cutting linear stapler (TLC 55) forks is inserted. The bowel must be aligned evenly on the forks before the instrument is fired (Figure 3). The bowel walls are sewn together with the stapler and the stoma is established by the cutting knife within the cutting linear stapler (TLC 55) (Figure 3A). The stapled suture line is inspected for bleeding, which, if present, is controlled with interrupted sutures.
Traction sutures (A, A′) are placed on the mesenteric border of each segment, and another is placed centrally (B) to permit traction on the end of the suture line on the antimesenteric border (Figure 4). The common lumen can be closed with the application of a noncutting linear stapler (TL 60). The excess bowel wall beyond the suturing instrument is excised (Figure 5). Any bleeding points after the removal of the stapling instrument are controlled with interrupted sutures.
With time and experience, it has been found preferable to close this opening in a vertical manner from B to B′, thus approximating A to A′. This creates crossed staples only at the ends (B and B′), which are then carefully inspected for possible suture reinforcement. Again, any bleeding points are controlled with interrupted sutures. The lines of closure are carefully inspected, and the excess intestine outside of the staple lines is excised. The security of the suture line is evaluated, and the antimesenteric border can be approximated if desired with interrupted sutures for distance of the anastomosis.
The mesentery is completely approximated with interrupted sutures (Figure 6). The approximation may be performed before the anastomosis is created. The mesentery must be completely approximated to avoid any possibility of later internal herniation of a loop of intestine. The patency of the anastomosis is tested by palpation between the thumb and the index finger.