1993 Volume 35 Issue 6 Pages 1290-1298_1
The endoscopic technique originally developed to remove gastric lesions with intrasub-mucosal injection of saline remains room for improvement when applied to flat lesions in the colon. The thin submucosal layer possibly allows mechanical procedures to affect the proper muscle. The narrow and tortuous channel of the colon may also make it hard to place a cutting snare on an appropriate site of the lesion area. In this study we assessed the advantages of our removal method in 355 flat lesions in the colon. The notable procedures of our method as compared to the original technique are as follows: 1) injection of saline to produce a larger protrusion for the following snaring procedure, 2) placing a cutting snare on the midportion of the protrusion to protect the proper muscle layer against mechanical damage, 3) an use of a hexagonal shaped-cutting snare with a small needle which we devised to fix it correctly on the lesion area and 4) cutting off tissue by combining a larger current power (60 W) and tight squeeze of the snare to minimize the tissue damage. We estimated our technique as to be useful when a lesion was removed successfully within 3 minutes. High useful rates were obtained regardless of the protrusion shapes and of the location of lesions (shapes : subpedunculated, 97.5% ; sessile, 97.2% and broadly-based, 96.2%, locations : between folds, 98.9%, on a fold, 98.0% and behind a fold or inner site of curved area, 91.3%). Histology of resected specimens revealed clearly that the submucosal tissue was cut off its upper part, suggesting strongly that the proper muscle was insusceptible to mechanical procedure. It was also confirmed histologically that the tissue damage of the cut ends of resected specimens was minimal. No complications occurred in all cases. From the present results, we conclude that our method is practical and safe technique for removing the flat colon tumors endoscopically which have been detected increasingly by recent advance of endoscopy.
