Novel Technique for Identification of Ureters Using Sodium Fluorescein

Background: The unique property of sodium fluorescein has made it ideal for use in medical applications such as diagnostic ophthalmology and intravenous angiography. It is mainly excreted via the renal system and although extensively used in these diagnostic applications, it has not been widely used to aid in the visualization of the ureters. It is possible to visualize the urinary tract by shining a source of light and studying the fluorescence using a special filter. The goal of our study was to assess the real-time visualization of ureters using intravenous sodium fluorescein under the stimulus of a 530 nm wavelength light.

Materials And Methods: Nine 250 gm Wister rats were given an intravenous dose of 0.01 ml of sodium fluorescein. A laparotomy was immediately performed following the administration of dye. Anesthesia was performed with an intraperitoneal dose of ketamine-xylazine. The retroperitoneum was exposed and observed under an alternating white xenon and a 530 nm excitation light with an objective to visualize the organs captured within the fluorescence of the compound (sodium fluorescein).

Results: Under xenon light, the location of the kidneys and urinary bladder were visualized, but not the ureters. The light was then changed to a 530 nm wavelength mode when the location and orientation of the ureters was visualized along with the peristaltic movements. Fluorescence visualization of the ureters was noted 5-10 min following kidney visualization. In addition, the vascular structures in close proximity to the ureters were also visualized. None of the rats underwent any retroperitoneal dissection, and in one case, partial mobilization of a kidney was undertaken. All rats were euthanized at the completion of the procedure.

Conclusion: Intravenous administration of sodium fluorescein enables fluorescence visualization of the ureters in a rat model, after activation with a 530 nm light transmitter.