Background and study aims: Knowledge of the exact location of colorectal lesions is necessary but difficult to establish during surgery. Thus, endoscopic tattooing has been used as an important preoperative marker for identification. Using the conventional technique, we injected tattooing agents directly into the colonic wall. However, to make sure that the tattooing agents were adequately injected into the submucosal layer, and to prevent spillage into the peritoneal cavity, we modified the conventional method and developed a new tattooing technique: using India ink with prior and subsequent injection of saline into the submucosa. The aim of this study was to retrospectively assess the clinical utility and potential complications of the above two techniques of endoscopic tattooing using India ink.
Patients and methods: A total of 153 patients underwent laparoscopically assisted colectomy at the National Cancer Center Hospital East, Kashiwa, Chiba, Japan, between June 1994 and December 1999, and 91 patients underwent preoperative endoscopic tattooing by either the conventional or the new technique. The conventional and new techniques were used from June 1994 to December 1997 (n = 36) and from January 1998 to December 1999 (n = 55), respectively. Informed consent was obtained from all the patients.
Results: Using the conventional technique, the exact location of the lesion was identified in 31 of 36 cases (86.1 %) during surgery. The complications of this procedure were silent local peritonitis in two patients and reactive lymph node swelling in one patient (3/36, 8.3 %). Using the new technique, in 54 of 55 cases lesions (98 %) were easily identified (p = 0.034),and in only one there was a small leakage of India ink into the peritoneal cavity (1/55; 1.8 %), no other serious complications were observed.
Conclusions: The results demonstrate that our new technique for endoscopic tattooing is probably better than the conventional technique for clinical use, in terms of diagnostic accuracy and safety, but this would have to be proven in a randomized comparison.