Colonic Interposition for Benign Disease

Although a variety of methods are available to re-establish gastrointestinal continuity after esophageal resection, the most commonly used esophageal substitute is the stomach. In situations where the stomach is not available either as a consequence of prior surgery or for oncologic concerns when the tumor involves a significant portion of the lesser curve and cardia, a colon interposition is an excellent alternative. The transverse colon based on the ascending branch of the left colic artery is a reliable esophageal substitute that has the benefit of a consistent blood supply and long length. Drawbacks to esophageal replacement with a colon graft compared with a gastric pull-up include the increased time and complexity and the necessity of three anastomoses (esophago-colo, gastro-colo, and colo-colo). In addition, use of a colon graft requires preoperative evaluation with colonoscopy or barium enema to exclude colonic mucosal abnormalities, and bowel preparation before the operation. While long-term functional results after a colon interposition can be excellent, there are technical details that are important to minimize potential pitfalls and maximize the long-term advantages of a colon graft, the major one being protection of the residual squamous esophageal mucosa from reflux-induced injury that can lead to the redevelopment of Barrett’s esophagusandinrareinstancesesophagealadenocarcinoma. Preoperative Evaluation Preoperative evaluation of a patient for colon interposition must take into consideration the primary esophageal pathology but also the patient, the status of the colon, and the planned route of reconstruction. Evaluation of the patient begins with a careful history and physical examination. Specific questions regarding the patient’s history should include a review of any chronic colonic symptoms as well as the presence of colonic pathology such as diverticulosis, Crohn’s disease, ulcerative colitis, prior polyps, or malignancy. In addition, the patient should be questioned about prior colonic resection or history of an abdominal aortic aneurysm repair. In patients that have not had a recent colonoscopy, the colonic mucosa should be examined before use of the colon for esophageal replacement. At a minimum an air contrast barium enema should be obtained, but colonoscopy is preferred since it allows direct examination of the colonic mucosa and biopsy or removal of polyps or lesions. The role of virtual colonoscopy with computed tomographic scanning remains to be determined. The colon should be prepared before surgery, and my preference is to admit the patient into thehospitalthedaybeforesurgeryandcleansethecolonwith 4 liters of Go-Lytely combined with oral Neomycin and metronidazole. Enemas are avoided to minimize the potential for mucosal edema in the colon. The most common portion of colon used for esophageal replacement is the transverse colon based on the ascending branch of the left colic artery from the inferior mesenteric artery (Fig. 1). Although the routine use of preoperative angiography to examine the colonic vasculature is controversial, I find it useful to prevent unnecessary dissection and wasted time in the operating room since anatomic variants of the colonic arteries are common, and in elderly patients a patent inferior mesenteric artery cannot be assumed to be present. Angiographic criteria favorable for a transverse colon graft include the presence of a patent inferior mesenteric artery, an intact marginal artery, a single middle colic trunk, and a separate origin of the right colic artery. Absolute requirements include a patent inferior mesenteric artery and marginal artery. 1 If a stenosis is present in the inferior mesenteric artery, the standard transverse colon graft should be avoided and an alternate vascular pedicle or graft used. Venous drainage of the colon parallels the arterial system. Typically the left colic vein joins the splenic and portal system, and the marginal vein also provides colonic venous drainageviathehemorrhoidalveinandinferiorvenacavaifit is left in continuity when the colon graft is divided. In the rightcolicsystemthereisgreatervariationandoftennodominant vein, and it has been suggested that marginal venous drainage may in part be responsible for the higher infarction and anastomotic leak rate reported to occur with use of the right colon for esophageal replacement. 2