VM41 - The Accessory Middle Colic Artery’s Role in Sigmoid Colon and Rectum Perfusion: Implications for Ultra-Low Rectal Cancer Surgery

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Purpose/Background: The accessory middle colic artery (AMCA) may play a significant role in the blood perfusion of the left colon and rectum, but there is currently a lack of studies confirming its impact. Our present study investigated the effect of the AMCA on blood perfusion in the left colon, particularly the sigmoid colon and rectum, following high tie of the inferior mesenteric artery (IMA) during radical surgery for rectal cancer.Furthermore, we explore the potential value of the AMCA in achieving tension-free anastomotic reconstruction in ultra-low rectal cancer surgery. This video provides a detailed description of our surgical steps when the patient has an AMCA during laparoscopic intersphincteric resection (ISR).

Methods/Interventions: This study involved a 65-year-old male patient who was diagnosed with rectal cancer 3 months prior, with the tumor located 1.0-1.5 cm from the dentate line. Preoperative MRI and PET-CT scans revealed metastatic lymph nodes in the mesorectum. The patient subsequently underwent neoadjuvant chemoradiotherapy. Before the surgery, a CTA examination was performed, which confirmed the presence of an AMCA. Our previous research indicated that when the AMCA is present, good blood perfusion to the rectum and sigmoid colon can be maintained even after high tying the IMA. Therefore, ISR was planned for this patient. During the surgical procedure, a high tie of the IMA was performed. Following the completion of the total mesorectal excision (TME), the ISR procedure commenced. First, dissection between the sphincters was completed laparoscopically, after which the rectum was transected through the anus. Once the rectum was transected, the proximal bowel was pulled out through the anus. Blood perfusion of the rectum and sigmoid colon was assessed using a laser speckle flow imaging (LSFI) system. Finally, the rectum and a portion of the sigmoid colon were resected, the specimen was removed, and anastomosis was successfully performed.

Results/Outcomes: The surgery lasted 3 hours and 20 minutes, with an intraoperative blood loss of 10 ml. During the procedure, the splenic flexure of the colon was not mobilized. After the proximal bowel was pulled out through the anus, the LSFI results confirmed that the rectum and sigmoid colon maintained good blood perfusion. Furthermore, the anastomosis was tension-free, indicating its safety. However, to ensure patient safety, a preventive ileostomy was performed. Postoperatively, the patient recovered smoothly, starting to eat and ambulate the day after surgery. The abdominal drainage tube was removed on the sixth postoperative day, and the patient was discharged on the seventh postoperative day. No postoperative complications were reported.

Conclusion/Discussion: In this video, we demonstrate that the presence of an AMCA allows for the maintenance of good blood perfusion to the rectum and sigmoid colon, even after high tying the IMA. This finding suggests that during ultra-low anterior resection, including ISR, if the AMCA is present, there is no need to mobilize the splenic flexure. This is due to the significant flexibility in determining the length of bowel to be resected, which ensures that there is sufficient proximal bowel available for anastomosis reconstruction. Consequently, we can achieve a tension-free anastomosis with adequate blood supply.