Fluorescence-guided autonomic nerve preservation during total mesorectal excision: A prospective pilot study

Abstract Introduction: Total mesorectal excision has significantly improved oncologic outcomes in rectal cancer; however, post-operative urinary and sexual dysfunction remain important concerns due to inadvertent pelvic autonomic nerve injury. Intraoperative identification of these nerves is particularly challenging following neoadjuvant chemoradiotherapy. This study evaluated the feasibility of indocyanine green (ICG)-guided fluorescence imaging for the selective visualisation of pelvic autonomic nerves during minimally invasive TME. Patients and Methods: In this prospective pilot feasibility study, 24 patients undergoing minimally invasive TME for rectal adenocarcinoma were included. Twelve patients underwent conventional nerve-preserving TME guided by anatomical landmarks, whereas twelve received intravenous ICG (0.5 mg/kg) 12 h preoperatively. Near-infrared imaging was used intraoperatively. Short-term post-operative outcomes assessed included the day of urinary catheter removal, need for recatheterisation and incidence of urinary tract infection. Results: The median age was 57 years, and baseline characteristics were comparable between groups. In the fluorescence-guided group, autonomic nerves appeared as distinct non-fluorescent structures against a fluorescent background. Earlier catheter removal was observed in the ICG group (predominantly post-operative day 2 vs. day 3). Recatheterisation was required in one patient in the fluorescence-guided group compared with three in the conventional group. One UTI occurred in the conventional group, whereas none were observed in the fluorescence-guided group. No adverse reactions to ICG were recorded. Conclusion: Pre-operative low-dose ICG administration is feasible and safe for real-time intraoperative visualisation of pelvic autonomic nerves during minimally invasive TME and may improve early post-operative urinary outcomes. Larger prospective studies are warranted.