Endoscopic tattooing of the colon: clinical experience.

Nonpalpable lesions of the colon can be difficult to locate intraoperatively. We have demonstrated in an experimental study in dogs that the colon can be endoscopically "tattooed" by injecting dye through a flexible needle into the wall of the colon. At laparotomy, the resulting "tattoo" is then visible on the serosal surface of the bowel. This technique allows precise surgical localization of endoscopically identified lesions simply by visualizing the dye. Our initial clinical experience tattooing 15 colonic lesions in 12 patients is presented. In all patients, the endoscopically injected dye (1 per cent indocyanine green) was easily visualized on the serosal surface of the colon at surgery. The dye remained at the site of injection for at least 36 hours allowing tattooing to be performed the day before surgery. No significant complications were encountered with only one patient developing an inflammatory reaction at the site of injection. This experience demonstrates the clinical utility of endoscopic tattooing of the colon to permit accurate intraoperative localization of small or nonpalpable lesions.