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.