Objective: To test the feasibility of using a newly developed device for laparoscopic lymphatic mapping of the colon by simultaneous and quantitative detection of both tissue coloration and radioactivity.
Methods: Four pigs were used in this study. In each animal, both blue dye and radioisotope injections were utilized. Lymphatic mapping was performed laparoscopically in the sigmoid mesocolon and in the right mesocolon. A solution containing a mix of 35 microcuries of Technetium Tc-99 sulfur Colloid and 1 mL of a vital blue dye was administered subserosally by percutaneous insertion of a 25 gauge needle under laparoscopic control. The new device for automated sentinel-node detection consists of a gamma-probe coupled with a laser device and can be passed through a regular 10-mm trocar. The device detects simultaneously both radioactivity and quantitative tissue coloration. Nodes showing a radioactivity at least 5 times higher than that of the background or that had a blue colorant concentration were considered our sentinel nodes.
Results: Laparoscopic simultaneous and quantitative detection of sentinel nodes was feasible in all pigs. One or more sentinel nodes were identified by either the blue dye or radioisotopic technique in both the sigmoid and right mesocolon. Quantitative tissue coloration detection led to the recognition of additional nodes that were not apparently colored to the naked eye.
Conclusion: Laparoscopic sentinel node detection using a device combining gamma and color detection is feasible in the porcine model. The significance of nodes apparently clear but positive with the quantitative detection technique should be further evaluated.