BACKGROUND: Monopolar hot biopsy forceps (HBF), bipolar HBF, and cold biopsy forceps (CBF) followed by bipolar electrocoagulation are used clinically to simultaneously perform a biopsy and coagulate diminutive colon polyps and angiomata. Our purpose was to conduct a randomized, controlled study to evaluate the safety of these different techniques in the canine right colon. METHODS: After right colotomy in 8 mongrel dogs, colonic mucosa was grasped en face, tented, and biopsy performed in randomized order. The dogs were sacrificed after nine days and the biopsy sites were identified and histologically examined. RESULTS: Monopolar HBF caused an overall mean rate of acute serosal whitening of 29% compared with 0% for bipolar HBF and CBF and 6% for CBF/bipolar probe. Histologically confirmed transmural injury 9 days after biopsy occurred in 44% of monopolar HBF compared with 5% of bipolar HBF, 0% of CBF, and 50% of CBF/bipolar probe. CONCLUSIONS: Monopolar HBF had significantly higher rates of acute serosal whitening and histologic transmural damage than bipolar HBF or cold biopsy alone. On the basis of these results, monopolar HBF should be avoided for coagulation of small or flat right colon lesions such as diminutive polyps or angiomata.
BACKGROUND: Monopolar hot biopsy forceps (HBF), bipolar HBF, and cold biopsy forceps (CBF) followed by bipolar electrocoagulation are used clinically to simultaneously perform a biopsy and coagulate diminutive colon polyps and angiomata. Our purpose was to conduct a randomized, controlled study to evaluate the safety of these different techniques in the canine right colon. METHODS: After right colotomy in 8 mongrel dogs, colonic mucosa was grasped en face, tented, and biopsy performed in randomized order. The dogs were sacrificed after nine days and the biopsy sites were identified and histologically examined. RESULTS: Monopolar HBF caused an overall mean rate of acute serosal whitening of 29% compared with 0% for bipolar HBF and CBF and 6% for CBF/bipolar probe. Histologically confirmed transmural injury 9 days after biopsy occurred in 44% of monopolar HBF compared with 5% of bipolar HBF, 0% of CBF, and 50% of CBF/bipolar probe. CONCLUSIONS: Monopolar HBF had significantly higher rates of acute serosal whitening and histologic transmural damage than bipolar HBF or cold biopsy alone. On the basis of these results, monopolar HBF should be avoided for coagulation of small or flat right colon lesions such as diminutive polyps or angiomata.