Left Hemicolectomy
What the Examiner Expects
Resection of the splenic flexure and descending colon with a colorectal or colocolic anastomosis, performed for left-sided colon cancers. The examiner expects you to ligate the inferior mesenteric artery at its origin from the aorta for adequate lymph node harvest and oncologic clearance. The splenic flexure must be fully mobilized to allow a tension-free anastomosis. Key anatomic hazards include the left ureter (crosses the iliac vessels at the pelvic brim), the gonadal vessels, and the spleen (traction injury during flexure mobilization). The marginal artery of Drummond provides collateral blood supply, and the arc of Riolan (meandering mesenteric artery) provides SMA-IMA communication.
Key Examiner Focus Points
- Indications: splenic flexure or descending colon cancer
- Ligate the inferior mesenteric artery (IMA) at its origin for cancer
- Mobilize splenic flexure for a tension-free colorectal anastomosis
- Left ureter and gonadal vessels at risk during retroperitoneal mobilization
- Colorectal or colocolic anastomosis depending on level of resection
Common Curveballs
You injure the spleen while mobilizing the splenic flexure
Assess the severity. Minor capsular tears can be managed with topical hemostatic agents. If bleeding is significant and cannot be controlled, splenectomy may be required — be prepared. Postop, the patient will need vaccinations (pneumococcal, meningococcal, H. influenzae).
After IMA ligation, the descending colon conduit appears ischemic
The blood supply to the proximal colon now depends on the marginal artery from the middle colic. If the marginal artery is attenuated or the arc of Riolan is absent, the colon may be ischemic. Extend the resection proximally to well-vascularized transverse colon.
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