Alternative approaches to polyp extraction in colonoscopy: a proof of principle study

A limitation of determination of the completeness of resection in polypectomy is polyp fragmentation. When a polyp fragments, the pathologist cannot determine resection completeness. Alternative approaches to reduce polyp fragmentation include reducing shearing forces on the polyp or removing polyps through the instrument channel. The primary aim of this study was to assess fragmentation of polyps extracted using different approaches from conventional polyp retrieval.

Polyps (5-15 mm) resected by cold snare or cautery by 3 colonoscopists were extracted from the colonoscope using 1 of 4 techniques. Method I was the conventional method of pressing the suction valve button and retrieving the polyp through a trap. Method II involved removing the suction valve, covering the open suction valve cylinder with a finger. Method III used a Roth Net polyp retriever placed through the instrument channel. Method IV involved connecting a polyp trap to suction onto the instrument channel port. Fragmentation was defined as multiple pieces of the specimen in formalin, as grossly described by the pathologist. Alternative approaches (methods II, III, and IV) were all compared with the conventional method (method I).

The method I fragmentation rate of polyps was 60.3% (123/204). Method II extraction reduced fragmentation to 43.0% (52/121, P = .003), proving that fragmentation occurs with passage through the suction valve channel. Method III had a lower fragmentation rate of 23.1% (6/26, P < .001). Method IV likewise showed a reduced fragmentation rate of 18.5% (5/27, P < .001).

Polyp fragmentation is reduced by removal of the suction valve button. There is also a decrease in fragmentation rates in removing the polyp by connecting the polyp trap to the instrument port. Our study suggests that decreasing polyp fragmentation and improving pathology margin interpretability is possible through methods that extract polyps through the instrument port with currently available devices.