Transillumination Techniques for Vessel Identification During Small Colon Resection in Six Horses

Background: Transillumination has been described in human surgery to improve vessel visualization but has not been described in horses. Since the equine mesocolon contains a great amount of fat which restricts visualization of the vessels, this technique could be useful during small colon resection. Objectives: To describe transillumination of the mesocolon to provide an improved vessel identification during resection and anastomosis of the small colon in horses. Methods: Data of horses that underwent resection and anastomosis of small colon were recorded. Two transillumination techniques were used during resection and anastomosis of small colon. In a first technique, used on three horses, the operating lamp was used. It was lowered and tilted so that the assistant surgeon could lift the small colon so that the mesentery was between the lamp and the first surgeon eyes. In a second technique, used on further three horses, a smartphone with a rear LED flashlight turned on was placed into a sterile rectal sleeve. The device was placed on the surgical field and the portion of small colon to be resected was then laid over the smartphone, to backlight the vessels. The vessels were then identified and ligated. Results: Six horses referred for acute colic that underwent resection and anastomosis of the small colon were included in the study. Using both transillumination technique the mesocolon was backlit and the vessels were clearly and easily identified, dissected, ligated, and transacted without complications. The smartphone technique subjectively ensured a better operating position for the surgeon and less fatigue for the assistant. Conclusions: Transillumination techniques are useful to avoid damage when ligating vessels and using the flashlight of a smartphone is easier and provide safer and more accurate transection of them during small colon resection and anastomosis.