Colonic tattooing with India ink: benefits, risks, and alternatives.

Objective: To provide comprehensive information on key issues concerning colonic tattooing with India ink in reported literature.

Methods: A total of 735 citations on India ink alone were present in the English literature (1966-1995), including 16 on India ink and colonic tattooing. Nine major studies were identified and reviewed for 1) preparation before tattooing (type of ink used, sterilization process, colonic preparation, and antibiotic prophylaxis), 2) the tattooing process (technique and volume injected), 3) success in localization, and 4) complications.

Results: A'total of 447 cases of colonic tattooing with India ink have been reported. Major indication was preoperative marking of tumor site. Various India ink preparations were used. Ink was unsterilized in 57% (255/447), autoclaved in 42% (187/447), and gas sterilized in 1% (5/447) of cases. Colonic preparation varied similarly. Prophylactic antibiotics were used in 1% (5/447) of cases. Dilution of India ink varied from undiluted to 1:100 (with 0.9% saline). The volume injected ranged from 0.1 to 2 ml per site injected, commonly with tangential needle insertion and delivery of ink into the submucosa in the majority of the cases. Intraoperative localization was easier with multiple tattoo injections. Five reports of complications have been made. In only one instance did overt clinical complications develop. Risk of a clinical complication with colonic tattooing with India ink is 0.22%.

Conclusion: Marked variability in technique, as well as potential for reporting bias, limit the quantitative conclusions. In general, colonic tattooing with India ink is a safe, accurate, and inexpensive method for preoperative marking and prospective study of colonic lesions.