Case report on a rare complication after transanal total mesorectal excision (TaTME) for rectal malignancy vesicorectal fistula

Introduction and importance: Transanal Total Mesorectal Excision (TaTME) represents the latest surgical approach in rectal cancer management. We present a rare case of vesicorectal fistula (VRF) following a complication of TaTME surgery.Case presentation: A 67-year-old male underwent a Hartmann's procedure for perforated rectosigmoid cancer in 2019. He was lost to follow-up and re-presented in 2021 with synchronous cancer of the transverse colon and rectum. A two-team surgical approach was utilized: open subtotal colectomy (transabdominal approach) with concurrent excision of rectal stump (TaTME approach). Intraoperatively, an inadvertent bladder injury was identified and repaired. 8 months later, he re-presented with the passage of urine per rectum. Imaging and endoscopy revealed a VRF with cancer recurrence at the rectal stump.Clinical discussion: VRF is an uncommon complication of TaTME that carries a significant physical and psycho-logical impact on the patient. While shown to be a safe and useful technique, the long-term oncological outcomes of TaTME are still awaited. Unique complications have been reported with TaTME, including gas embolism and injuries to the genitourinary structures, in which the latter caused the eventual VRF formation in our patient.Conclusion: Revisional surgery for recurrent disease is challenging and can result in rare complications, especially in patients with distorted anatomy and when new surgical techniques are utilized. Radiotherapy further causes unpredictable tissue healing quality. The challenge remains for proper patient selection with individualization of surgical approaches, while keeping a close eye on the oncological outcomes of the patient.