What is the basic technique of Endoscopic Submucosal Dissection (ESD)?

Basic Technique of Endoscopic Submucosal Dissection (ESD)

Endoscopic submucosal dissection (ESD) is an advanced endoscopic technique that involves resecting the overlying mucosa along with the lesion itself by dissecting through the submucosal layer using electrocautery knives after submucosal injection. 1

Key Steps of ESD Procedure

1. Lesion Assessment and Preparation

• Carefully evaluate the lesion's characteristics (size, morphology, location)
• Determine if ESD is appropriate based on suspected depth of invasion
• Mark the borders of the lesion with 3-4 mm margin of normal surrounding mucosa 1

2. Submucosal Injection

• Inject solution into the submucosa to create a fluid cushion
• Preferred solutions include:
  • Sodium hyaluronate or colloidal solutions (provide longer-lasting lift than normal saline) 2
  • Consider adding a contrast agent and low concentration adrenaline 2
• Adequate lifting separates the lesion from the muscularis propria layer

3. Circumferential Incision

• Create a complete circumferential mucosal incision around the marked borders
• This isolates the lesion with surrounding normal mucosa 1
• Use specialized ESD knives for precise cutting

4. Submucosal Dissection

• Further inject submucosa under the lesion as needed
• Using controlled movements under direct visualization (often facilitated by a cap)
• Dissect through the expanded submucosal layer with an ESD knife
• Maintain traction and counter-traction for optimal visualization
• Continue dissection until the lesion is completely excavated in one piece 1

5. Management of the Resection Bed

• Inspect the resection bed for:
  • Complete removal of the lesion
  • Potential perforations
  • Bleeding vessels requiring hemostasis
• Consider closure methods when needed (suturing or over-the-scope clips) 1

Equipment and Tools

Essential Instruments

• Specialized ESD knives (various types available)
• Transparent cap attachment for the endoscope
• Injection needles
• Hemostatic devices
• Electrosurgical unit with appropriate settings 3

Types of ESD Knives

• Insulated-tip (IT) knives
• Needle-type knives
• Hybrid knives
• Flexible Maryland dissector (alternative option) 4, 3

Indications for ESD

ESD is primarily indicated for:

• Large lesions (>20 mm) where en bloc resection using standard EMR is difficult
• Lesions suspected to have superficial submucosal invasion
• Mucosal lesions with fibrosis
• Local residual early carcinoma after endoscopic resection
• Non-polypoid colorectal dysplasia in inflammatory bowel disease patients 1

Technical Considerations and Pitfalls

Anatomical Challenges

• The colon's narrow, tortuous lumen and thin wall increase complication risk compared to gastric ESD
• Right colon locations are associated with higher complication rates 2
• Retroflexion maneuvers carry increased perforation risk 2

Common Complications

• Perforation (main early adverse event)
  • Aspirational standard for perforation rate should be <0.5% 2
• Bleeding (2-5% risk)
  • Post-procedure bleeding rate should be <5% 2
• Recurrence (target <5% at 12 months) 2

Risk Mitigation

• Detailed inspection of the post-resection defect is essential
• Consider prophylactic closure of resection defects ≥20mm in the right colon
• Ensure availability of full-thickness closure methods (suturing, clips) 1, 2

Learning Curve and Expertise

ESD requires extensive training and experience due to its technical complexity. Endoscopists should:

• Develop skills progressively from simpler to more complex cases
• Master submucosal injection and dissection techniques
• Be proficient in managing complications
• Consider hybrid ESD techniques as a bridge between conventional EMR and full ESD for those developing skills 1, 5

ESD represents an advanced endoscopic technique that allows for en bloc resection of lesions that would otherwise require piecemeal removal or surgery, providing excellent histological assessment capabilities while maintaining a minimally invasive approach.