Since the introduction of the minimally invasive approaches, the benefits of laparoscopic colorectal resections, such a complete exploration of the abdominal cavity, minimal surgical trauma, and favorable surgical results when compared to the open approach, have been enhanced. However, the difficulties of intra-operative localization small cancers and polyps at the time of surgery without tattoo have been highlighted, due to reduced tactile feedback during laparoscopy. The precise lesion location must be identified pre-operatively as failing to identify the lesion for resection can result in open conversion or removal of the wrong bowel segment.
In this set-up, endoscopic India ink marking techniques during preoperative colonoscopy were implemented and this is current one of the preferred methods with approximately a 70 to 90% of successful intra-operative location. However, endoscopic documentation of the tattoo site with respect to the tumor can be inconsistent and at times misleading or difficult to interpret. According to the literature, the tattoo is visible and accurate in 60 to 90% of cases, visible but inaccurate in approximately 5 to 10% of cases and not visible in 15 to 20% of case. In up to 20% of patients, no tattoos were found and either intraoperative endoscopy and/or intraoperative specimen analysis was required to confirm that the lesion was within the resection specimen.
In cases of location failure, a complete review of the full length of the bowel is necessary. Laparoscopically enhanced visualization may be able to compensate for inconsistent documentation of the tumor´s distance from the anal verge. Identifying difficult spots, such as the splenic flexure, is definitely feasible at this point thanks to the laparoscopic instrumentation. Helpful maneuvers to visualize the tattoo may be the release of omental attachments or adhesion, or lateral mobilization of the colon, which may be hiding the ink on its posterior side. If any of these resources are unsuccessful, intraoperative colonoscopy may be useful for accurate localization.
Preoperative endoscopic tattooing is a safe and effective technique for intraoperative localization of colorectal lesions, improving the operative results of laparoscopic colorectal resections.