Perforation during underwater EMR.

Prasanna L. Ponugoti, MD, Douglas K. Rex, MD Indiana University School of Medicine, Division of Gastroenterology and Hepatology Indianapolis, Indiana, USA Underwater EMR is effective and safe and does not require submucosal injection. Here, we describe the first perforation during underwater EMR. A 62-year-old man had a 30-mm flat lesion in the proximal ascending colon visible only in retroflexion. It appeared that submucosal injection would move it too close to the colonoscope tip to permit easy therapy. During underwater EMR, transection of the first piece resulted in perforation (Fig. A), which was closed with 3 clips (Cook Endoscopy, Winston-Salem, NC; Fig. B). CT confirmed free air without fluid collections. The patient remained asymptomatic (he was afebrile and his white blood cell count was normal). Because the EMR was not completed, right hemicolectomy was performed 30 hours later. The perforation was adjacent to pericolonic fat, without peritoneal contamination. After primary anastomosis, the patient’s recovery was uneventful. D.K.R. performed >30 underwater EMRs of lesions >2 cm before and >20 after this perforation, all without adverse events. We believe this perforation was caused by the retroflexed instrument stretching the colon wall, preventing the lesion from floating. Fortunately, water did not enter the peritoneal cavity. Caution is appropriate when performing underwater EMR in retroflexion. Colonoscopists performing underwater EMR should look for the lesion floating as a safety predictor.