What is ligation and how is it performed surgically?

Surgical Ligation: Definition and Technique

Ligation is the surgical procedure of tying off a blood vessel, duct, or tubular structure with suture material to occlude it, prevent bleeding, or interrupt pathological flow.

Core Surgical Technique

Ligation involves placing a ligature (suture) around the target structure and securing it with a knot to achieve complete occlusion. The fundamental steps include:

• Identification and isolation of the vessel or structure requiring ligation through appropriate surgical exposure 1
• Placement of suture material around the structure, ensuring complete circumferential encirclement 1
• Securing with surgical knots that maintain adequate tension without slipping—the Roeder slip knot is commonly used in laparoscopic procedures and requires approximately 1125 grams of tension to induce reverse slipping when using 0/chromic catgut 1
• Verification of complete occlusion before completing the procedure 2

Context-Specific Applications

Arterial Ligation for Hemorrhage Control

For persistent epistaxis (nosebleed), surgical arterial ligation should be evaluated when bleeding is not controlled by packing or cauterization 3. The American Academy of Otolaryngology-Head and Neck Surgery recommends:

• Transendoscopic sphenopalatine artery ligation (TESPAL) as the preferred surgical approach, which can include concurrent anterior ethmoidal artery ligation 3
• Surgical ligation demonstrates superior safety compared to endovascular embolization, with stroke rates of 0.1% versus 0.9% for embolization alone 3
• TESPAL is more cost-effective than endovascular embolization and typically requires general anesthesia 3
• Complications occur in 2.1% to 3.8% of cases and may include skin/nasal necrosis, facial nerve paralysis, blindness, and stroke 3

Spinal Dural Arteriovenous Fistula

Surgical ligation through laminectomy is the definitive treatment for spinal dural arteriovenous fistulas 4. The procedure involves:

• Laminectomy exposure at the level of the intervertebral foramen 4
• Dural opening to visualize the fistula site 4
• Identification of the arterialized vein and direct ligation 4
• This approach is safe and reliable for treating these abnormal arteriovenous shunts 4

Laparoscopic Ligation Considerations

The Roeder knot provides a substantial safety factor ratio of 55:1 for vessels up to 3 mm diameter in laparoscopic surgery 1. Key technical points include:

• The knot is fashioned outside the abdomen and slipped along the ligature to the intended site 1
• Ligature tension required for vessels up to 3 mm diameter at 150 mmHg pressure is less than 5 grams 1
• The relationship follows the formula: T = 3/2 pr δ (where T=tension, p=pressure, r=vessel radius, δ=radius at ligature point) 1

Tubal Ligation

Pomeroy tubal ligation can be performed via laparoscopy using endoloop sutures or minilaparotomy 5. Both approaches demonstrate:

• Similar operative times (18.90 minutes for laparoscopy versus 23.12 minutes for minilaparotomy) 5
• Minor morbidity with both techniques 5
• Laparoscopy may be preferable when appropriate conditions and equipment are available 5

Critical Pitfalls

Incomplete ligation poses significant risks, particularly in cardiac surgery where incomplete left atrial appendage ligation exposes patients to residual embolic risk 2. Verification of complete closure is essential 2.

Suture material selection matters for temporary ligation—only polyglycolic acid sutures reliably achieve transient arterial occlusion, while plain gut and chromic gut are unreliable for this purpose 6.