What vessels are typically ligated during a sigmoidectomy?

Vessels Ligated in Sigmoidectomy

During a sigmoidectomy, the inferior mesenteric artery (IMA) is typically ligated, with the specific level of ligation determined by the clinical context and surgical approach.

Vascular Anatomy and Ligation Considerations

• In sigmoidectomy, the primary vessel requiring ligation is the inferior mesenteric artery (IMA), which is the main arterial supply to the sigmoid colon 1
• The inferior mesenteric vein (IMV) is also typically ligated during the procedure 2
• For benign conditions like sigmoid volvulus, a full oncological anterior resection with high ligation is not typically needed - the main consideration is ensuring adequate vascular supply to the remnant colon 3
• For malignant conditions, high ligation of the IMA at its origin is often performed to ensure optimal lymphadenectomy 4, 5

Surgical Approaches to Vessel Ligation

• Traditional mechanical ligature (ML) techniques for IMA ligation include double clipping, staples, or surgical thread 6
• Modern approaches increasingly utilize energized vessel sealing systems (EVSS), which have demonstrated comparable safety to mechanical ligature with potentially shorter operative times 6
• During laparoscopic sigmoidectomy, the IMA is typically approached and ligated early in the procedure to facilitate subsequent mobilization 7

Clinical Implications of Ligation Level

• High ligation of the IMA (at its origin from the aorta) provides oncologic benefit in sigmoid cancer by enabling more thorough lymphadenectomy 4
• In a study of 1,389 patients with sigmoid or rectal cancer, 3.1% had IMA node metastasis, with 25.6% of these patients remaining disease-free after 5 years following high IMA ligation 4
• The beneficial rate of high IMA ligation was 1.8% for non-disseminated sigmoid colon cancer 4
• The level of IMA ligation should be carefully considered as it affects blood supply to the remaining colon and potential anastomotic integrity 5

Potential Complications of Vessel Ligation

• Ligation of the IMV close to the IMA root can potentially lead to venous congestion in the rectosigmoid region 2
• Hemorrhagic events can occur with both mechanical ligature and energy vessel sealing systems, though they are relatively rare (1-2%) 6
• Careful attention to vascular anatomy is critical, as surgeons' intraoperative estimation of IMA ligation level correlates with postoperative CT findings in less than 50% of cases 5

Special Considerations in Sigmoid Volvulus

• In emergency sigmoidectomy for volvulus, the decision to perform isolated sigmoid colectomy versus high anterior resection should consider the vascular supply to the remnant colon 3
• For sigmoid volvulus cases, resection of infarcted bowel should be performed without detorsion and with minimal manipulation to prevent release of endotoxin, potassium, and bacteria 3
• In these emergency cases, end colostomy creation (Hartmann procedure) is often appropriate for hemodynamically unstable patients or those with significant comorbidities 3

Technical Considerations

• Laparoscopic approaches to vessel ligation are increasingly common and have shown comparable safety to open techniques when performed by experienced surgeons 1
• Proper identification and ligation of vessels is crucial, as anatomical variations can complicate the procedure 7
• The use of energy vessel sealing systems for IMA ligation has been associated with shorter operative times (200.7 vs 253.7 minutes) and hospital stays (8.1 vs 10.4 days) compared to mechanical ligature 6