Small-Dose Endoscopic Tattooing Using a Novel Needle for Localization Prior to Laparoscopic Surgery of Colorectal Cancer.

Backgrounds Endoscopic tattooing failure by deep mural injection or tattoo leakage-induced massive staining causes localization errors or decreased laparoscopic visualization. To overcome these, we developed a novel tattoo needle with comparatively shorter needle (length, 2.5 mm) and minimal-caliber catheter (volume, 0.3 mL). Aims The single-center, prospective observational study aimed to determine the efficacy and safety of a small-doze endoscopic tattooing prior to laparoscopic surgery for colorectal cancer, using the needle. Methods Patients with colorectal cancer indicated for laparoscopic surgery were recruited. With the novel needle, a single tattoo was created at the anterior wall close to the lesion. During laparoscopic surgery, surgeons assessed the tattoo visibility, tattoo leakage, and the disturbance of laparoscopic view by tattoo leakage. The primary endpoint was an accurate localization by visible tattoo. Secondary endpoints were adverse events related to tattooing, the need for intraoperative endoscopy, and tattoo leakage. Results A total of 383 tattoos in 358 patients were analyzed. Accurate tumor localization rate was 96.6% (95% confidence interval [CI]: 94.3-98.0%). No adverse events occurred. Intraoperative colonoscopy was performed in 7 (1.8%) patients with invisible tattoo. Tattoo leakage was found in 4.2% (95%CI: 2.6-6.7%), and leakage disturbed the laparoscopic view of the surgical plane in 0.7% (95%CI: 0.3-2.3%). Conclusions Prior to laparoscopic surgery for colorectal cancer, our endoscopic tattooing with a standardized protocol using a novel needle is considered a simple, highly reliable localization technique with an extremely safe profile, which would be valuable to reduce physician's efforts and redundant medical resources. Trial registration number UMIN000021012. Date of registration: June 2016.