Left Colectomy

Chapter 22


Left Colectomy



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Surgical Principles


The pattern of left colonic resection is defined by the indication for surgery, the need to facilitate a tension-free colo-colonic anastomosis, and the blood supply. The most common indication for isolated left colonic resection is neoplasia. In this case, a radical lymphadenectomy is necessary for staging and prognosis, and lymphatic drainage must be considered. Because the pattern of lymphatic drainage for the colon follows that of the arterial supply, the inclusion of the mesocolic envelope containing the inferior mesenteric artery (IMA) and its branches, with ligation of the IMA close to its origin, ensures that this is achieved. This is referred to as a high ligation of the IMA. This approach may devascularize the entire left colon, requiring its resection and the mobilization of the distal right colon for anastomosis to the upper rectum.


Other indications for left colonic resection include diverticular disease, ischemia, Crohn disease, sigmoid volvulus, rectal prolapse, and secondary involvement in noncolonic processes, such as ovarian carcinoma. None of these conditions requires high ligation of the IMA, and in these cases it may be acceptable to ligate only the relevant branches of the IMA, perform a less extensive mobilization of the left colon, and create a tension-free anastomosis.



Anatomy for Preoperative Imaging


For colonic carcinoma, computed tomography (CT) of the chest, abdomen, and pelvis provides preoperative staging of the disease. CT includes identification of distant metastases, gross local lymph node involvement, and local invasion of the primary tumor (Fig. 22-1, A). Full colonoscopic evaluation determines the presence of synchronous lesions. For benign disease, CT and colonoscopy may help to identify pathologic features, such as the extent of Crohn disease or ischemia, that may affect approach and extent of dissection.





Vascular Anatomy


The anatomy of the vascular supply to the colon is demonstrated in Figure 22-2. Knowledge of these vessels, the autonomic nerves, and the lymphatic drainage, as well as its relationship to the spleen, pancreas, kidney, and ureter, is required for successful completion of the left hemicolectomy (Figs 22-3 and 22-4, A).



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Aug 12, 2016 | Posted by in ANATOMY | Comments Off on Left Colectomy

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