Which arteries should be ligated (and at what level) for a right hemicolectomy, transverse colon resection, left hemicolectomy or sigmoid resection, and low anterior or abdominoperineal resection for rectal cancer?

Arterial Ligation Levels for Colon Resections

The extent of colonic resection and arterial ligation is determined by the blood supply and distribution of regional lymph nodes, with wider margins required due to obligatory ligation of the arterial blood supply to achieve adequate lymphadenectomy. 1

General Principles of Vascular Ligation

For oncologic resections, at least 12 lymph nodes must be resected to clearly define stage II versus III disease and to identify potential lymph node metastases. 1 This requirement drives the extent of vascular ligation, as lymph nodes follow the arterial distribution. 2

The resection should include a segment of colon of at least 5 cm on either side of the tumor, though wider margins are typically included because of obligatory arterial ligation. 1

Right Hemicolectomy

For cecal and ascending colon cancers, perform right hemicolectomy with ligation of:

• Ileocolic artery at its origin from the superior mesenteric artery (SMA) 2
• Right colic artery at its origin (when present—this vessel has variable anatomy and may be absent) 2, 3
• Right branch of the middle colic artery at its origin 2, 3

The right colic artery has various origins and ascending colon cancers show various patterns of lymph node metastases, necessitating right hemicolectomy rather than limited resection. 2 If the right colic and middle colic arteries share a common trunk, this common trunk should be ligated. 2, 3

Transverse Colon Resection

For transverse colon cancers, the arterial ligation depends on tumor location:

Right-sided transverse colon:

• Ligate the middle colic artery at its origin from the SMA, or if the right colic and middle colic arteries have a common trunk, perform right hemicolectomy with ligation of this common trunk 2, 3

Left-sided transverse colon:

• Ligate the left branch of the middle colic artery at its origin 2
• If the left branch of the middle colic artery has an independent replaced origin, lymph node dissection should be modified according to this variant anatomy 2, 3

The middle colic artery forks into right and left branches, each with different branching variations that must be identified preoperatively or intraoperatively. 2, 3

Left Hemicolectomy and Sigmoid Resection

For descending and sigmoid colon cancers, the level of inferior mesenteric artery (IMA) ligation remains controversial, with two acceptable approaches:

High Tie Approach:

• Ligate the IMA at its origin from the aorta 4, 5
• This ensures complete lymphadenectomy of nodes around the IMA origin 4

Low Tie with Lymph Node Dissection:

• Ligate the IMA just below the origin of the left colic artery (LCA) 4, 5
• Combined with lymph node dissection around the origin of the IMA 4, 5
• This preserves blood flow to the anastomosis while achieving equivalent oncologic outcomes 4, 5

Both approaches yield equivalent overall survival and relapse-free survival rates, even in lymph node-positive cases. 4, 5 The low tie with lymph node dissection is anatomically less invasive and may reduce anastomotic complications by preserving blood flow through the LCA. 4

Additional considerations for sigmoid resection:

• If the left colic artery and first sigmoidal artery share a common trunk, lymph nodes along this common trunk must be removed 2
• For sigmoid colon cancer, 6.3% of patients have lymph node metastases along the superior rectal artery, so these nodes should be included in the dissection 2

Low Anterior Resection and Abdominoperineal Resection for Rectal Cancer

For rectal cancer, perform:

• High ligation of the IMA at its origin from the aorta (standard approach) 4
• Alternatively, low ligation just below the LCA origin with lymph node dissection around the IMA origin 4, 5
• Ligate the superior rectal artery (continuation of the IMA) 2

The level of vessel ligation should be documented, as it is relevant for subsequent completion proctectomy or revisional surgery. 1 Visualization and preservation of autonomic nerves (periaortal, presacral) should be attempted during dissection. 1

Common Pitfalls to Avoid

Inadequate lymph node harvest: Failure to achieve 12 lymph nodes risks understaging and inappropriate omission of adjuvant therapy. 1 This requires central vascular ligation with adequate mesenteric resection. 6, 7

Failure to identify vascular variations: The right colic artery is absent in many patients, and the middle colic artery has significant branching variations. 2, 3 Preoperative imaging or careful intraoperative assessment is essential to plan appropriate ligation levels.

Inadequate blood supply to anastomosis: While high tie of the IMA ensures complete lymphadenectomy, it may compromise anastomotic blood flow. 4 Low tie with lymph node dissection offers equivalent oncologic outcomes with potentially better perfusion. 4, 5

Incomplete documentation: The method of vessel ligation (tie, clips, staplers, energy devices) should be documented, as it informs follow-up imaging interpretation. 1