Mucosal proctectomy and ileoanal anastomosis is being increasingly performed on patients with familial polyposis, many of whom have undergone previous subtotal colectomy followed by endoscopic surveillance and polypectomy with monopolar electrocautery (MPEC) or, more recently, argon laser (AL). Our aim was to compare the ease of mucosal dissection following polypectomy with MPEC or AL in the canine colon. At celiotomy, two groups of fifteen 5-to 7-mm sessile polyps were surgically created in the descending colon of five mongrel dogs. Six weeks later, each animal underwent flexible colonoscopy and polyp fulguration with MPEC (15 polyps) and AL (15 polyps). Fulguration was performed weekly for 2-3 weeks until all polyps had been obliterated. Ten weeks later, mucosal dissection was performed with the operating team unaware of prior treatment. Mucosal dissection was scored for dissectability (1 to 4; 1 = facile, 4 = difficult), blood loss, operating time, and number of mucosal perforations with the last three parameters normalized to 100 cm2 of mucosa. AL and MPEC were equally effective at polyp obliteration; however, more AL-treated polyps required retreatment than MPEC-treated polyps (P < 0.05). After AL treatment, mucosal dissection was more facile [dissectability index (mean ± SEM): 1.4 ± 0.2 vs 2.6 ± 0.2; P < 0.05] and could be performed more quickly (15.1 ± 2.4 min vs 23.6 ± 2.7 min; P < 0.01). After AL treatment, mucosal dissection could be performed with fewer mucosal holes (1.6 ± 1.0 vs 7.7 ± 1.0 holes, P < 0.007) and less blood loss (67.2 ± 19.3 cc vs 105.6 ± 24.5 cc, P < 0.03). We conclude that argon laser is as effective as MPEC in colonic polyp ablation and may allow the surgeon an easier and safer mucosal dissection at the time of subsequent mucosal proctectomy.
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