Mastering Piecemeal EMR: Lessons from a Complex Transverse Colon Polyp

Introduction

Large sessile polyps in the transverse colon represent one of the most common yet technically demanding scenarios in therapeutic colonoscopy. This expert live case demonstrates the complete workflow for managing a bulky transverse colon polyp using piecemeal endoscopic mucosal resection (EMR), from initial optical assessment through to defect closure.

Optical Assessment with BLINK Criteria

“Before we resect anything, we need to characterise this polyp using BLINK criteria to determine the best resection strategy.” - 3:20

The case begins with systematic polyp characterisation using the BLINK optical diagnosis framework. The operator methodically evaluates surface pit pattern, vascular architecture, and morphological features to confirm benign histology and plan the resection approach.

Underwater and Injection-Assisted EMR Technique

“Watch how the underwater view gives us superior visualisation of the polyp margins compared to traditional air insufflation.” - 12:45

The resection employs a hybrid approach combining underwater EMR with targeted submucosal injection. Water immersion causes the polyp to float away from the muscularis propria, creating a natural safety margin. For areas requiring additional lift, dilute adrenaline with methylene blue is injected submucosally.

Key technical pearls include careful snare placement at the polyp-normal mucosa junction, controlled slow closure of the snare, and systematic resection in overlapping pieces.

Managing Intraprocedural Bleeding

“When you encounter arterial bleeding during piecemeal resection, the key is not to panic - cap the scope, fill with water, and identify the precise source.” - 32:10

The most valuable teaching moment comes during management of intraprocedural arterial bleeding. The operator demonstrates a structured precision framework: cap the endoscope tip, fill with water for improved visualisation, then identify the exact bleeding vessel.

Margin Assessment and Residual Ablation

Following piecemeal resection, the operator performs meticulous inspection of the resection margins using white light and NBI. Small islands of residual adenomatous tissue are treated with snare-tip soft coagulation (STSC).

“The decision between en bloc and piecemeal comes down to polyp size and morphology - above 20mm in the colon, piecemeal EMR remains the pragmatic choice.” - 65:00

Clip Closure of the Resection Defect

“Complete clip closure of the resection defect significantly reduces the risk of delayed bleeding in large EMR cases.” - 58:30

The case concludes with systematic clip closure using a zipper technique. This is emphasised as particularly important for transverse colon lesions where the wall is thinner.

Key Takeaways

• Systematic optical assessment using BLINK criteria should precede every polypectomy decision
• Hybrid underwater/injection EMR combines the safety advantages of both techniques
• Structured bleeding management (cap, water, identify, treat) prevents escalation
• Complete margin inspection with NBI after piecemeal resection catches residual tissue
• Prophylactic clip closure is recommended for large transverse colon EMR defects