932 POLYPS RETRIEVED WHEN TRAP IS ATTACHED TO INSTRUMENT PORT ARE MORE FREQUENTLY INTACT AND INTERPRETABLE THAN WHEN REMOVED BY CONVENTIONAL METHOD

Abstract

A major limitation of determination of the completeness of resection in colonoscopy polypectomy is polyp fragmentation. When a polyp fragments, the pathologist cannot determine resection completeness. In current practice, the polyp is retrieved following traversing the entirety of the colonoscope and the specimen negotiates lumen diameter change at the suction valve. Alternative approaches to reduce polyp fragmentation include removal of the suction valve button or alternatively removing polyps through the instrument channel thereby bypassing issues of polyps traversing the suction valve passage entirely. Polyps with sizes ranging from 5-15 mm removed en bloc by cold snare or snare cautery by three colonoscopists were extracted using one of four techniques in a prospective manner. Method I was the conventional method of pressing suction valve button and retrieving the polyp through a trap. Method II involved removing the suction valve, sealing the open suction valve cylinder to apply suction. Method III used a Roth Net polyp retriever (US endoscopy) placed through the instrument channel. Method IV involved connecting a polyp trap to suction(etrap-US endoscopy) onto the instrument channel port. Fragmentation was defined as multiple pieces in gross description based on pathologist review of the specimen in formalin. Technical failures were defined when a polyp was unable to be retrieved using the specific methodology assigned. Differences between groups were calculated by two sided Fisher’s exact test. The Method I fragmentation rate of polyps was 60.3%. Method II had a reduced polyp fragmentation rate 43% (p=0.003) proving that polyp fragmentation occurs with passage through the suction valve channel. Method III had an even lower fragmentation rate of 23.1% (p= <0.001) which was a proof of principle approach that extraction through the instrument channel could reduce fragmentation even further. Method IV was a cost effective approach of direct application of polyp removal through instrument channel but still reduced the fragmentation rate to 19.2%% (p=<0.001). 3 of the 26 polyps removed by Method IV were technical failures but all 3 failures were retrieved fragmented through conversion back to Method I. The decrease in fragmentation rate was seen in both snare cautery and cold snare. Polyp fragmentation is reduced and interpretability of specimen improved by simply removal of the suction valve button. There is a further decrease in fragmentation rates in using a retrieval approach involving connecting the polyp trap to the instrument port. Our study suggests that decreasing polyp fragmentation and improving pathology margin interpretability may be possible through methods that extract polyps through the instrument port rather than requiring polyps to traverse the entirety of the scope as is currently practiced.Phases: (I) Conventional Polypectomy Technique with finger depressing suction valve button (II) Technique with finger covering the opening of the suction valve port with valve button removed (III) Technique using Roth Net extracting polyp through instrument channel (IV) Technique with polyp trap attached to instrument channel port with suction applied.View Large Image Figure ViewerDownload Hi-res image Download (PPT)