An incision is made in the peritoneal reflection close to the lateral wall of the bowel from the tip of the cecum upward to the region of the hepatic flexure (figure 1). A liberal margin should be ensured in the region of the tumor. Occasionally, the full thickness of the adjacent abdominal wall may require excision to include the local spread of tumor. Since the entire hepatic flexure is usually removed as part of a right colectomy, the hepatocolic ligament, which contains some small blood vessels, must be divided and ligated, but there will be no blood vessels of importance in the peritoneal attachments along the right gutter. With the lateral peritoneal attachment divided, the large bowel may be lifted mesially with the left hand, while the loose areolar tissue lying under it is dissected off with a moist gauze sponge over the right index finger (figure 2). In elevating the right colon toward the midline, the surgeon must positively identify the right ureter and be certain that it is not injured. Care is taken also toward the top of the ascending colon and near the hepatic flexure to avoid injury to the third portion of the duodenum, which underlies the large bowel (figure 3). The raw surface remaining after the intestine has been freed and brought outside the peritoneal cavity is covered with warm, moist gauze pads. The middle colic vessels are identified, along with the right-hand branches heading toward the hepatic flexure and the planned zone of transection. The mesentery of the large bowel is clamped and divided just distal to the hepatic flexure or wherever the bowel is to be resected. The right branches or all of the middle colic vessels are divided and doubly ligated. The bowel at the selected level for division is freed of all mesentery, omentum, and fat on both sides. All vessels must be carefully ligated. The right half of the greater omentum is divided near the greater curvature of the stomach and excised along with the right colon.
The terminal ileum is prepared for resection some distance away from the ileocecal valve, depending upon the amount of blood supply that must be sacrificed to ensure excision of the lymph node drainage area of the right colon. After the small intestine has been prepared at its mesenteric border, a fan-shaped excision of the mesentery to the right colon is carried out. This usually includes part of the right branches of the middle colic vessels. In the presence of malignancy, the lymph node dissection should descend as far as possible along the course of the right colic and ileocolic vessels without compromising either the middle colic vessels or the superior mesenteric vascular supply of the remaining small bowel (figure 4). The blood vessels of the mesentery are doubly tied.
A straight vascular clamp, or some other type of straight clamp, is applied obliquely to the small intestine about 1 cm from the mesenteric border to ensure a serosal surface for the placement of sutures for the subsequent anastomosis. Stone, Kocher, or Pace-Potts clamps are next applied across the large intestine, which is then divided between the clamps. The intervening section of bowel, with its fan-shaped section of mesentery and nodes, is excised. The divided proximal end of the small intestine is covered with gauze moistened with saline, and closure of the stump of the large bowel is started unless an end-to-end or end-to-side anastomosis is planned. Many surgeons prefer to use stapling devices, in which case the colon and terminal small bowel are resected using a linear stapling device. The ileum and transverse colon may then be anastomosed in an antimesenteric side-to-side manner using the technique shown in Chapter 45, Resection of Small Intestine, Stapled. As staples may not be universally available, the techniques for hand-sewn anastomoses are shown in the continuing figures of Chapter 55.
The end of the colon is closed by a continuous absorbable suture on an atraumatic needle and whipped loosely over a Pace-Potts or similar noncrushing clamp (figure 5). Interrupted 000 silk sutures placed beneath the clamp may be used. The clamp is then opened and removed. If a continuous suture is used, it is pulled up snugly and tied. A single layer of 000 silk Halsted mattress sutures is placed about 2 or 3 cm from the original suture line; care being taken that no fat is included. As these sutures are tied, the original suture line is invaginated so that serosa meets serosa (figure 6). The surgeon must determine before closing the ends of the colon whether an end-to-end, end-to-side, side-to-end, or lateral anastomosis is to be carried out (figures 14, 16 to 18).
The end-to-side approximation is physiologic, simple, and safe to perform. The small intestine, still held in its clamp, is brought up adjacent to the anterior taenia of the colon (figure 7). The small intestine should retain a good color and give evidence of adequate blood supply before the anastomosis is attempted. If its color indicates an inadequate blood supply, the surgeon should not hesitate to resect a sufficient length until its viability is unquestionable. Next, the omentum, if not previously excised, is retracted upward, and the anterior taenia of the transverse colon is grasped with Babcock forceps at the site chosen for anastomosis (figure 7). Following this, the edge of the mesentery of the small intestine should be approximated to the edge of that of the large intestine, so that herniation of the small intestine cannot occur beneath the anastomosis into the right gutter (figure 14). This opening is closed before the anastomosis is started, since on rare occasions the blood supply may be injured by the procedure and the viability of the anastomosis jeopardized. A small, straight crushing clamp is applied to the anterior taenia, including a small bite of the bowel wall (figure 8). Following this, the clamps on the terminal ileum, as well as on the anterior taenia of the transverse colon, are so arranged that a serosal layer of interrupted 000 mattress or nonabsorbable synthetic sutures can be placed, anchoring the terminal ileum to the transverse colon (figure 9). The two angle sutures are not cut and serve as traction sutures (figure 9). An opening is made into the large intestine by excising the protruding contents of the crushing clamp that has been applied to the anterior taenia (figure 10). An enterostomy clamp is then applied behind each of the crushing clamps. The crushing clamps are removed, and the terminal ileum is opened; likewise, the crushed contents of the transverse colon are separated. Sometimes it is necessary to enlarge the opening in the mucosa of the colon, since the previous excision of the contents of the crushing clamp did not provide a sufficiently large stoma for satisfactory anastomosis. The mucosa is then approximated with a continuous locked nonabsorbable suture on atraumatic needles, which is started in the midline posteriorly. The sutures, A and B, are continued as a Connell inverting suture around the angles and anteriorly to ensure inversion of the mucosa (figures 11 and 12). Interrupted fine 000 silk sutures are preferred by some for closing the mucosal layer. An anterior row of mattress sutures completes the anastomosis. Several additional mattress sutures may be placed to reinforce the angles (figure 13). The patency of the stoma is tested. It should permit introduction of the index finger. If the tension is not too great, the raw surface over the iliopsoas muscle may be covered by approximating the peritoneum of the lateral abdominal wall to the mesentery.
The second method shown is a direct end-to-end anastomosis (figures 15 and 16). The discrepancy in the size of the terminal ileum and the transverse colon can be overcome safely by attending to certain technical details. Added luminal circumference can be provided by exaggerating the oblique division of the terminal ileum. During the anastomosis, slightly larger bites are taken in the colonic side to compensate for the discrepancy between the two sides of the anastomosis. Following completion of the anastomosis, any remaining gap between the mesenteries is approximated. The patency of the lumen is determined by palpation.
If a side-to-end anastomosis is preferred by the surgeon, the stump of the small intestine is closed as previously described for the large intestine. The small intestine is then brought up to the open end of the large intestine (figure 17), the posterior row of serosal sutures is placed, the small intestine is opened, and the continuous mucosal suture or the inverting sutures are placed as well as, finally, the anterior serosal sutures of interrupted 000 silk or nonabsorbable synthetic material. Whenever this type of procedure is carried out, care should be taken that only a very small portion of small intestine protrudes beyond the suture line, since blind ends of bowel that are in the peristaltic line form a stagnant pouch against which peristalsis tends to work, increasing the chance of eventual breakdown.
In the fourth method, the ends of the large and small intestines are closed, and a lateral anastomosis is carried out. Only a small portion of small intestine should protrude beyond the suture line. The small intestine should be anchored to the colon with interrupted sutures of silk or nonabsorbable synthetic material, including both angles of the stoma as well as the closed end of small bowel (figure 18). The stapled equivalent of each of the variations can be found in earlier chapters illustrating the use of various stapling instruments in small bowel anastomoses.