Lung W Lau, MD1, Michael Luciano, PhD2, Martin Schnermann, PhD2, Jaepyeong Cha, PhD1. 1Children’s National Medical Center, 2National Cancer Institute
Introduction: Ureteral identification during laparoscopic surgery can be difficult, with iatrogenic ureteral injuries reported as high as 7.6 percent during colorectal and gynecologic surgeries. Current methods of identification, such as ureteral stents or watching for peristalsis, are not always effective. In settings of inflammation and distorted anatomy, ureteral identification is even harder, with greater risk for injury. The use of fluorescent dye can improve intraoperative ureteral identification without the need for any additional, invasive procedures. While no ureter-specific fluorescent dye exists for clinical use, our team has previously described the development of a pre-clinical ureter-specific dye, UL-766. Here, we present the use of the fluorescent dye during laparoscopy to assist in ureteral identification in an inflammatory swine model.
Method: With approval from IACUC, two 20-25kg swine underwent laparoscopic abdominal surgery with use of an FDA-approved fluorescent laparoscopic system. Inflammation was created by sharp and blunt dissection of right ureter from surrounding tissues. Tissue surfaces were further irritated by rubbing with surgical gauze. The animals were allowed to recover and returned to the operating room after seven days. Images of the inflamed right retroperitoneum were taken before and after intravenous injection of the novel fluorescent dye. The dye was dosed at 120ug/kg, injected via the ear vein. The time to fluorescent visualization of the ureters was measured. Fluorescent signal was measured for up to four hours from initial dye injection. Ureter was dissected from inflamed tissue under fluorescence laparoscopy, and injury was replicated via partial transection. Urine was collected and analyzed by high-performance liquid chromatography (HPLC) for analysis of metabolic changes of the dye.
Results: Despite surrounding tissue erythema and edema, ureteral visualization under fluorescent laparoscopy was achieved within 5-10 minutes after dye injection. The fluorescent signal was visible for at least 4 hours after injection. The fluorescent dye showed ureteral injury that would not have been seen under standard laparoscopy (Figure 1). Urine analysis show chemically unaltered dye after excretion.
Conclusion: UL-766 is a novel fluorescent dye useful for intraoperative identifications of ureters in an inflamed abdomen and visualization of ureteral injuries. Excretion of the dye is minimally metabolized indicating a likely linear excretion profile. With more preclinical data, this novel dye can become a valuable tool to prevent iatrogenic ureteral injuries during laparoscopic abdominal and pelvic surgeries.
Figure 1: Fluorescent visualization of ureteral injury with effluent of urine from the ureter, visualized with and without fluorescence laparoscopy (blue).
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 91854
Program Number: P683
Presentation Session: Poster Session (Non CME)
Presentation Type: Poster
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