Complex colorectal polyps (defined as >2cm) or those positioned in difficult anatomic locations may be major endoscopic challenges. Underwater ESD (UESD) has recently emerged as a potential technical solution to facilitate removal of complex polyps. The major benefits of UESD are: gravity-assistance independence, magnification, hydro-dissection, reduced tissue burn artifact and electrosurgical smoke reduction. In addition, endolumenal tissue traction and counter-traction, cornerstone principles of effective dissection, have been confined to limited methods ranging from clipping/retraction to using two scopes. Despite clear benefits of ESD (R0 resection and low recurrence rate), it remains a technically challenging procedure with higher perforation rates compared to EMR. In this case, we employed a hybrid approach using UESD facilitated by a novel endoscopic double balloon system which permitted polyp tissue retraction, to decrease technical difficulty and increase safety.

Case Description: 68 year old male, large complex polyp located in the ascending colon.

PMH: OSA, PVC, HLD, HTN

UESD-R technique (briefly): The balloons were deployed behind and in front of the lesion. After the balloons were inflated, a sealed ‘therapeutic zone’ was created. Water aggregation was due to patient and polyp position (6 o’clock). A mucosal incision was made at the proximal lesion margin and developed. The incision leading edge was developed further using underwater dissection. At the appropriate point the mucosal edge was clipped to the base of the fore balloon. Using variable tension on the fore balloon, tissue dissection continued until resection. After the procedure, the specimen was removed using the fore-balloon as a specimen retrieval bag.

UESD-R total procedural time was 120 minutes. No perforations were observed.

Paris classification was IIa

Size: 6x3cm

Final histology: Tubulovillous adenoma

The double balloon system enabled UESD-R. This led to an enhanced sense of stability of the scope in a difficult situation. The combined benefits of UESD and retraction appeared to be additive when tackling complex polyps unamenable to gravity assistance and should be studied further.