Figure 6.3. Left hemicolectomy. (A) Diagram of the colon showing the resection margins (jagged lines) of a left hemicolectomy. (B) Diagram of the colon after resection.
ileocecal valve, such as a right hemicolectomy, care must be taken not to use so much barium that the small bowel is flooded with contrast medium, obscuring the colon.
A left hemicolectomy involves resection of the splenic flexure, descending colon, and sigmoid with anastomosis of the distal transverse colon to the rectosigmoid (Fig. 6.3).
Total colectomy refers to resection of the entire colon; the rectum remains, and continuity is usually established with an anastomosis from the ileum to the remaining rectum (Fig. 6.4).
Total proctocolectomy refers to resection of the entire colon and rectum. In this circumstance, a permanent ileostomy must be performed. Subtotal colectomy refers to resection of the entire colon proximal to the distal sigmoid (Fig. 6.5). Generally, an anastomosis is created between the ileum and the remaining sigmoid to establish continuity. In some patients after significant colonic resection (subtotal colectomy, right hemicolectomy, etc.), the small bowel proximal to the anastomotic site will develop an appearance of pseudohaustration and dilatation termed colonization.
Abdominoperineal resection (AP resection) is generally performed for tumors below the levator ani muscle. The rectum is removed, and a permanent colostomy is created at the distal descending colon (Fig. 6.6).
Hartmann's procedure, generally performed for diverticulitis, consists of resection of the sigmoid colon, closure of the rectal stump, and an end colostomy. Usually, the bowel continuity is reestablished later, after inflammatory changes have subsided. This procedure and the ileal pouch-anal anastomosis (IPAA) are discussed in more detail shortly. Other operations are fairly self-explanatory, including ileocecal resection and transverse colectomy.
The automatic stapling device is now used frequently for the creation of colonic anastomoses. These devices reduce operative time and permit lower rectal anastomoses than hand-sewn anastomoses. In patients who have undergone rectal or rectosigmoid resection, it has been suggested that a baseline plain film of the abdomen be obtained in the early postoperative period to evaluate the integrity of the staple ring (Fig. 6.7). In the early postoperative period a disrupted staple ring
is suggestive of anastomotic dehiscence (Fig. 6.8) . Animal studies have shown that the staple ring should remain intact for at least 4 weeks, but after that time migration of staples may occur as a result of healing with fibrosis . To evaluate for disruption of the ring, the staple line must be viewed clearly en face, and additional films at different angles may therefore be necessary .
Now being increasingly performed by laparoscopy, colonic resection is considered to be a well-tolerated and safe procedure for benign disease. Although laparoscopic surgery is also being increasingly performed for malignant disease, there is some concern about the adequacy of resection with this technique, as well as the possibility of spread of cancer to the port site and long-term survival [5,6].
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