The operation is performed chiefly for tumor of the left colon or a complication of diverticulitis.
Tumors of the left colon are frequently of the stenosing type. Patients with this condition often come to the surgeon with symptoms of impending intestinal obstruction.
When obstruction is not complete, the bowel can best be prepared over a period of days by oral administration of the appropriate cathartics and a clear liquid diet for the last 48 hours. The frequency with which cathartics and cleansing agents are administered will vary depending upon the amount of obstruction. The level and nature of the obstruction may be confirmed by barium enema; however, colonoscopy allows biopsy for pathologic identification, identification and removal of additional lesions such as polyps, and potential evaluation of the proximal colon. In the presence of total obstruction, a nasogastric tube is passed for decompression and the colon is emptied from below with enemas. Evaluation of the distal colon with colonoscopy is valuable and a virtual colonoscopy may be obtained with special CT imaging to evaluate the proximal colon. A baseline carcinoembryonic antigen (CEA) blood test is obtained. If this and enzymatic liver function tests are elevated, CT or imaging scans of the abdomen and liver may be obtained to evaluate metastatic spread. Perioperative antibiotics are given. A Foley catheter is inserted after induction of anesthesia.
General anesthesia is preferred.
The patient is placed in a comfortable supine position and rotated slightly toward the operator. A slight Trendelenburg position may be used, although it can rarely lead to lower extremity compartment syndrome. If the colon tumor or process is in the lower left colon or sigmoid region, most surgeons will position the patient in a modified lithotomy manner using Allen stirrups supporting the knees and ankles. This will allow for prepping and draping of the rectal region for potential passage of an EEA stapling device. The legs are spread and the knees elevated sufficiently to provide this access to the rectum but not so high or wide as to interfere with the abdominal portion of the operation. If there is any doubt as to the locations, lithotomy position is recommended.
The skin is prepared in the routine manner.
The operator stands on the patient's left side. A liberal midline incision is made centered below the level of the umbilicus. The liver as well as other possible sites for metastasis are explored. The small intestines are then packed away medially with warm, moist packs. A pack is placed toward the pelvis and another along the lateral wall up to the spleen.
Precautions against possible spread of the tumor should include limited manipulation of the growth. As soon as possible, the tumor should be covered with gauze and its major blood supply clamped.
With the bowel at the point of the lesion held in the left hand, the lateral peritoneal reflection of the mesocolon is incised close to the bowel except in the region of the tumor over as wide an area as seems essential for its free mobilization (Figure 1). Following this, the bowel is retracted toward the midline and the mesentery is freed from the posterior abdominal wall by blunt gauze dissection. Troublesome bleeding may occur if the left spermatic or ovarian vein is torn and not ligated. The left ureter is identified because it must not be drawn up with the mesentery of the intestine and accidentally divided. A fan-shaped incision of sufficient size is made so that the entire left colic artery and vein down to their origins can be removed in order to maximize removal of regional lymph nodes (Figure 2). Some surgeons perform this division as soon as possible to minimize angiolymphatic spread of tumor from manipulation and traction of the specimen. In this technique, originally called “no touch,” it is essential that the surgeons have already identified the left ureter as well as the inferior mesenteric and sigmoid vessels (see Anatomy Plate 3, Vessels 8 and 9). At least 10 cm of margin from the gross border on either side of the lesion should be allowed. The contents of the clamps applied to the mesentery are tied. The mesenteric border of the bowel at the proposed site of resection is cleared of mesenteric fat in preparation for the anastomosis (Figure 3).
In most patients, the splenic flexure of the colon is mobilized to avoid an anastomosis under tension. This maneuver is easier and safer to accomplish if the midline incision is extended up to the xyphoid. This technique is shown in Figures 15, 16, and 17. Alternatively, the omentum may be removed in its relatively avascular junction along the left colon until the splenocolic region is reached. The descending left colon is then mobilized superiorly along the extension of the lateral line of Toldt. By approaching both ends toward the middle, the sometimes difficult splenocolic omental attachments are safely visualized and divided with minimal risk of splenic injury.
Most surgeons would currently use a stapled closure for a left hemicolectomy or sigmoidectomy, as described in Plate 82. In either case, care must be taken to divide distally below the rectosigmoid junction both to avoid leaving sigmoid diverticula and because it allows better mobility of the rectum and easier advancement of the EEA stapler. In cases where the surgeon does not have access to staplers, the following hand-sewn method is included. Paired crushing clamps of the Stone or similar type are placed obliquely across the bowel above the lesion within 1 cm of the limits of the prepared mesentery (Figure 4). The field is walled off with gauze, and the bowel is divided. A pair of noncrushing clamps is then applied to the prepared area below the lesion, and the bowel is divided in a similar fashion. The ends of the large intestine are brought end to end to determine whether the anastomosis can be carried out without tension. The clamps are approximated and manipulated so that the posterior serosal surface of the intestine is presented, to facilitate placement of a layer of interrupted mattress 000 silk sutures (Figure 5). The mesenteric border should be free of fat to achieve accurate approximation of the serosa. The sutures at the angles are not cut and are utilized for traction (Figure 6).
Enterostomy clamps are placed several centimeters from the crushing clamps, and the crushing clamps are removed (Figure 6). The portions of excessive bowel that were beyond the clamps may be excised. The field is completely walled off with moist, sterile gauze packs, and a direct open anastomosis is carried out. The mucosa is approximated with a continuous lock suture on an atraumatic needle starting in the middle of the posterior layer (Figure 7). At the angle, the lock suture is changed to one of the Connell type to ensure inversion of the angle and the anterior mucosa (Figures 8 and 9). A second continuous suture is started adjacent to the first one and is carried out in a similar fashion (Figure 10). After the mucosa has been accurately approximated, the two continuous sutures, A and B, are tied with the knot on the inside (Figure 11). A layer of interrupted 000 silk sutures or nonabsorbable sutures is utilized to approximate the anterior serosal layer. Particular attention is given to either angle to ensure accurate and secure approximation.
Alternative techniques for colon anastomoses include the use of single layer of delayed absorbable interrupted sutures with knots within the lumen and the use of stapling instruments. The latter technique is shown in Plate 61, Colon Anastomoses, Stapled.