Anterior Resection of Rectosigmoid: Side-to-End Anastomosis (Baker)

The low-lying lesions of the rectum and rectosigmoid may be resected and bowel continuity established anterior to the sacrum in a variety of ways. Although the end-to-end anastomosis (Plate 80) can be used, side-to-end anastomosis is advantageous in cases with considerable discrepancy in size between the resected bowel and the rectal stump, particularly in obese patients. When the lesion is so low that abdominoperineal resection, with sacrifice of the rectum, ordinarily would be indicated, and in the presence of distant metastases, or when the patient refuses to give permission for a permanent colostomy, bowel continuity can be established by a very low side-to-end anastomosis. This approach may occasionally be needed in colostomy (Hartmann's) closure, and a similar ileorectal anastomosis can be used in closing an ileostomy (e.g., after total colectomy for pseudomembranous colitis).

The principles of cancer surgery should be observed, including en bloc excision of the lymphatic drainage area and early ligation of the inferior mesenteric vessels near the point of origin (Figures 1 and 2). The blood supply to the sigmoid will be sustained through the marginal artery of Drummond via the middle colic artery arising from the superior mesenteric artery. The malignant lesion of the rectosigmoid should be at least 8 cm above the anus unless the anterior resection is carried out for palliation alone. At least 5 cm and preferably more of the bowel should be resected below the malignant tumor to assure removal of all adjacent lymph nodes. The continuity can be reestablished after the descending colon, the splenic flexure, and the left portion of the transverse colon are mobilized (Figure 3).

The entire right colon can be freed from its lateral peritoneal attachments and rotated to its embryologic position on the left side of the abdomen, if more mobility is desired.

The advantages of the side-to-end anastomosis include assurance of a larger and more secure anastomosis than may be possible by the end-to-end method.

After the lesion has been proved to be malignant by microscopic examination, and polyps or secondary lesions ruled out by appropriate colonoscopic and barium studies of the colon, the patient is shifted to a clear liquid diet for a day or so before surgery. A preliminary computed tomography scan with IV contrast may reveal distal spread and locate the courses of the ureters. For cancers below the peritoneal reflection, an endorectal ultrasound study will aid in the staging of the extent of disease. Appropriate tumors should be evaluated for radiation therapy and chemotherapy prior to operation. The rectum is irrigated with saline or a povidine-iodine solution. The tube is left in place for rectal decompression. An indwelling urethral catheter ensures a collapsed bladder, providing better exposure of deep pelvic structures. Systemic antibiotics are given.

General endotracheal anesthesia is satisfactory. Spinal anesthesia may be used.

The patient is placed near the left side of the table and so immobilized that the Trendelenburg position can be assumed during the final anastomosis without difficulty.

The skin is prepared from the symphysis up to the epigastrium. If a stapled anastomosis is planned, Allen stirrups are used to create a modified lithotomy position allowing concurrent preparation and draping for later access to the rectum. The perineum and rectum are prepared and included in the draping if stapling is planned.

A midline incision is made, starting just above the symphysis and extending down to the umbilicus and around it on the left side. The height to which the incision is carried in the epigastrium depends on the location of the splenic flexure. Because it will be necessary to detach the splenic flexure, easy exposure of this area must be provided. Undue tension of the left half of the colon and splenic flexure will tear the splenic capsule, causing blood loss and risking splenectomy.

After the abdomen is opened, a self-retaining retractor is inserted, and the liver is palpated for evidence of metastasis. Palpation should be carried out well over the top of both lobes of the liver as well as on the undersurface. Likewise, lymph nodes along the course of the inferior mesenteric artery and at the bifurcation of the aorta are inspected for evidence of involvement. The position and fixation of the tumor are ascertained by palpation. In the presence of metastasis to the liver or seeding throughout the general peritoneal cavity, a sleeve type of segmental resection is indicated. When a palliative resection is carried out, wide dissection of the inferior mesenteric blood supply up to the point of origin in the region of the ligament of Treitz is not necessary.

After it has been decided that the lesion is resectable, that an anterior resection is warranted, and that adequate bowel can be resected distal to the tumor, the small intestines are walled off and the transverse colon and splenic flexure are mobilized (Figure 4).

While the omentum is held upward, sharp dissection is used to divide the attachment of the omentum to the transverse colon. A few blood vessels may need to be ligated during this procedure. Opening into the lesser sac above the transverse colon ensures an easier and safer separation of the omentum from the splenic flexure of the colon, particularly in the obese patient. Again, great care must be exercised as the splenocolic ligament is divided in order to avoid tearing the splenic capsule. Clamps should be applied in this area so that the contents of the splenocolic ligament can be carefully divided and ligated (Figure 5).

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The peritoneum over the region of the left kidney is divided as gentle traction is maintained downward and medially on the splenic flexure of the colon. There is a tendency to grasp the colon and to encircle it completely with the fingers. This tends to puncture the thinned out mesentery. Rents can be avoided if a gauze pack is used to gently sweep the splenic flexure downward and medially (Figure 6). Usually, it is unnecessary to divide and ligate any vessels during this procedure. The peritoneum in the left lumbar gutter is divided, and the entire descending colon is swept medially.

The rectosigmoid is freed from the hollow of the sacrum as shown in Plates 70 and 71, Total Mesorectal Excision. The sigmoid is first separated from any attachments to the iliac fossa on the left side, and the left gonadal vessels and the ureter are identified throughout their course in the field of operation (Figure 7). Often, especially in the female, a very low-lying lesion can be mobilized and lifted up well into the wound.

After the bowel has been freed from the hollow of the sacrum, the fingers of the left hand should separate the right ureter from the overlying peritoneum by blunt dissection (Figure 8). The peritoneum is incised some distance from the tumor, and the rectum is freed further down to the region of the levator muscles using the mesorectal dissection (Plates 70 and 71). Division of the middle hemorrhoidal vessels with the suspensory ligaments may be necessary to ensure the needed length of bowel to be resected below the tumor. The surgeon should not hesitate to divide the peritoneal attachments in the region of the pouch of Douglas, to free the rectum from the prostate gland in the male and from the posterior wall of the vagina in the female. The inferior mesenteric artery is freed from the underlying aorta to near its point of origin (Figure 9). Three curved clamps are applied to the inferior mesenteric artery, and the vessel is divided and ligated with 00 silk. The inferior mesenteric vein should be ligated at this time, before the tumor has been palpated and compressed due to the manipulation required during resection.

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After the mesenteric vessels have been ligated and the rectum has been mobilized adequately, a Pace-Potts noncrushing clamp is applied across the bowel at least 5 to 10 cm below the tumor (Figure 10A). The position of both ureters should once again be identified before the clamp is applied. A straight clamp is applied 1 cm proximal to the noncrushing clamp, and the bowel is divided (Figure 10B). As soon as possible the specimen is wrapped in a large pack held in place by encircling ties (Figure 11).

It is reassuring for the surgeon, especially in obese patients, to see active pulsations at the anastomotic site, and the surgeon should take the time to free the mobilized colon and to loosen any tension on the middle colic vessels. Procaine, 1 percent, can be injected into the mesentery to strengthen pulsations in elderly patients or in the presence of large fat deposits in the mesentery (Figure 11). The Doppler apparatus may be used to verify the adequacy of the blood supply. The small bowel should be returned to the abdomen from the plastic bag, since the base of the mesentery of the small intestine can compress the middle colic vessels, particularly if the small intestine is placed on the abdominal wall above and to the right of the umbilicus (Figure 12). The blood supply improves as the colon resection nears the middle colic vessels, since the descending colon is now dependent upon the marginal vessels of Drummond arising from the middle colic vessels (Figure 12). The entire transverse colon as well as the right colon may be mobilized by detaching the omentum and the peritoneal attachments as indicated by the dotted line (Figure 12).

The mesentery is divided up to the bowel wall (Figure 13) where active pulsations have been identified. The mesentery to the sigmoid is further mobilized and divided until a sufficient amount of bowel has been isolated proximal to the lesion.

The remaining colon must be sufficiently mobilized then to reach the rectal stump loosely and without tension. Extra mobility is mandatory, since postoperative distention of the bowel and subsequent tension on the suture line must be anticipated.

A decision is made for an end-to-end anastomosis with or without a stapling instrument or a side-to-end anastomosis. The adequacy of the exposure, the amount of omental fat, and finally, the discrepancy between the sizes of the upper and lower lumens may influence the final technical approach.

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The bowel is divided obliquely after the mesentery has been cleared off to about 1 cm from the clamp (Figure 14). The mobility of this segment of bowel is tested by bringing it down to the region of the rectal stump to be absolutely certain that side-to-end anastomosis can be carried out without tension. If the initial segment is too tight, additional transverse colon may be mobilized. The hepatic flexure can be freed as well as the entire right colon. Any attachments constricting the mesentery of the descending colon can be divided. The presence of active arterial pulsations should be determined while the closed end of the colon is held deep in the pelvis. The end of the bowel is closed using a running absorbable suture followed by 000 interrupted silk Halsted mattress sutures. Alternatively, a stapled closure and division with a GIA instrument can be used. Some surgeons oversew this staple line with interrupted 000 silks for better security and inversion.

The taenia adjacent to the mesentery along the inferior surface of the mobilized segment is grasped with Babcock forceps, and traction sutures (A and B) are placed at either end of the proposed opening (Figure 15). These sutures keep the inferior taenia under traction during the subsequent placement of the posterior serosal row of interrupted 00 silk sutures (Figure 16). The traction suture (B) should be within 2 cm of the closed end of the bowel, since it is undesirable to leave a long blind stump of colon beyond the site of the anastomosis. After this, the Pace-Potts clamp is removed. The margins of the rectal stump are protected by gauze pads to avoid gross spilling and contamination. It is advisable to excise the edge of the rectal stump if it has been damaged by the clamp. The color of the mucosa and viability of the rectal stump should be rechecked. Any bleeding points on the edge of the rectal stump are grasped and ligated with 0000 absorbable sutures. It has been found useful for exposure to insert a traction suture (C) in the midportion of the anterior wall of the rectum (Figure 17). This keeps the bowel under modest traction and aids in subsequent placement of mucosal sutures. A noncrushing clamp may be applied across the colon to avoid the possibility of gross contamination. An incision is made between the traction sutures (A and B) along the taenia, and the lumen of the proximal bowel is opened (Figure 15). All contamination is removed in both angles of the openings. The same type of traction suture (C) can be placed in the midportion of the wall of the sigmoid. Interrupted 000 silks are placed full thickness through the posterior edges of both the descending colon and rectal stump (Figure 16). The knots are tied within the lumen and then cut. This layer provides absolute full thickness control for the posterior suture row. A double-ended running 00 absorbable suture is tied in the posterior midline. This proceeds laterally as a running, locking, continuous suture until each suture line reaches the corner. A Connell inverting suture is then used as the closure proceeds from both corners to the midline. Thereafter, an interrupted row of 00 nonabsorbable sutures are placed in a submucosal mattress manner for inversion and security of the completed anterior anastomosis (Figure 18).

This provides a large stoma. The patency of the stoma is determined by palpation and the integrity of the anastomosis can be checked by filling the pelvis with saline and then insufflating the rectum with air using an Asepto syringe. The appearance of air bubbles signals the needs to reevaluate the suture line or even in the entire anastomosis.

After completing the anastomosis, the surgeon should recheck the adequacy of the distal blood supply and be certain that the proximal colon is not under tension. The hollow of the sacrum is irrigated with saline and the placement of a closed-system Silastic catheter in this region is optional.

To release tension from the suture line as the bowel becomes dilated in the early postoperative period, it is useful to anchor some fat pads to the peritoneal reflection in the iliac fossa. This seals off entrance into the pelvis as it anchors the bowel in this area. Likewise, the free medial edge of the mesentery should be approximated to the right peritoneal margin in order to cover all raw surfaces. As this peritoneum is closed, the course and location of both ureters must be identified repeatedly to avoid including them in a suture.

The Baker's side-to-end anastomosis as illustrated is a very safe approach when the surgeon must perform a hand-sewn anterior or low anterior resection. Most surgeons, however, have access to and proficiency with stapling instruments. In these circumstances, the proximal descending colon is transected with a cutting linear stapler (GIA) while the rectal stump is divided between a pair of suture lines created with a noncutting linear stapler (TA) stapling device (Figure 19). The rectum is divided between the staple lines and the specimen removed. The staple line of the proximal colon is partially resected along the antimesenteric border so as to create an opening that allows passage of a circular stapler (EEA) anvil, whose shaft will exit through the taenia, approximately 5 cm proximal to this opening. A purse string is then applied about the anvil shaft and tied in a snug manner (Figure 20). The open cut end of the proximal colon is closed with the noncutting linear stapler. The main circular stapler (EEA) instrument is passed, with its disposable trocar retracted within, until it reaches the staple line of the rectal stump. Under direct vision, the surgeon guides the circular stapler (EEA) trocar out through the posterior rectal bowel wall about ½ cm behind the suture line. A purse string is carefully placed about the penetrating trocar. The trocar is removed and the anvil inserted into the circular stapler (EEA) instrument within the rectum. The rectal purse string is tightened and both purse strings are inspected. The two segments of bowel are carefully brought together and the instrument is fired. The firing and release require adherence to the manufacturer's instructions to verify correct tightness or compression of the tissue before firing and the correct amount of loosening for the cap to tilt before careful removal. The surgeon verifies the presence of two intact tissue rings (donuts) containing the purse strings of both the proximal and distal colon walls. After inspection of the anastomosis, the air bubble test described above is most useful, as the surgeon cannot always see fully around the anastomosis. An advantage of bringing the circular stapler (EEA) stapler trocar out posterior to the rectal stump staple line is that it places the junction of the two staple lines (corners) somewhat anteriorly, where they may be most easily reinforced with interrupted 000 nonabsorbable mattress sutures.

The routine closure is performed.

The Foley catheter is removed in 1 to 5 days, depending upon how much bladder and presacral dissection was performed. Careful observation of the voiding pattern, volumes, and residual volumes determines successful recovery. The initial liquid diet is advanced as tolerated. The presacral drain is monitored for output and blood content. It is usually removed in a few days unless a urine leak is suspected on the basis of a large output of clear fluid with an elevated urea content.