S171 – Left hemicolectomy with anterior resection or proctosigmoidectomy
OHIP Urology Code — DIGESTIVE SYSTEM SURGICAL PROCEDURES · Schedule of Benefits
S171 is for a left hemicolectomy with anterior resection or proctosigmoidectomy. The procedure specifically includes an anastomosis below the peritoneal reflection and the mobilization of the splenic flexure. This procedure may be performed laparoscopically or with laparoscopic assistance, in which case the E793 premium (add 25%) applies. If a neo-rectal pouch is formed, E808 is payable in addition. This is a major surgical procedure typically performed by a general surgeon and is eligible for assistant and anaesthesia services.
When to Use
- Use S171 for a left hemicolectomy that specifically includes splenic flexure mobilization and an anastomosis below the peritoneal reflection.
- Use S171 when performing a proctosigmoidectomy that requires the same extent of mobilization and low anastomosis as defined in the procedure description.
Common Pitfalls
- Billing S171 when the procedure does not include splenic flexure mobilization or the anastomosis is not below the peritoneal reflection; ensure the operative report explicitly confirms these steps.
- Failing to append E793 when the procedure is performed laparoscopically, as this is a separate claim line that is not automatically triggered by the base code.
- Attempting to bill a second surgical assistant without prior authorization, as S171 is not on the pre-approved list for multiple assistants.
Billing Tips
- Always append E808 if a neo-rectal pouch is created during the same operative session, as this is a flat-fee add-on that must be claimed alongside S171.
- Verify that the operative report clearly documents the anatomical landmarks and the level of anastomosis to support the use of S171 over less complex colonic resection codes.
Effective: April 1, 2026
S. Digestive System Surgical Procedures
DIGESTIVE SYSTEM SURGICAL PROCEDURES
Surgical
Digestive System Surgical Procedures
All insured services must be documented in appropriate records establishing that an insured service was provided, the service claimed is the service rendered, and the service was medically necessary.
Anaesthesia basic units: 8.
Assistant basic units: 7.
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