Low Powered Colorectal Anastomosis After Rectal Excision (OASIS)

There are a variety of available anastomotic techniques to facilitate restorative surgery following total mesorectal excision (TME) for rectal cancer. However, there is no good quality evidence demonstrating the superiority of any single technique with regards to the potential sequalae of restorative surgery including anastomotic leakage and functional impact. Double-stapled anastomotic technique (DST) for colorectal anastomosis is the most widely used technique worldwide. An alternative to DST is the hand-sewn coloanal anastomotic (CAA) technique, which is traditionally reserved for patients with ultralow rectal tumours requesting restorative surgery or in cases of technical difficulties whereby a low colorectal anastomosis is converted to a coloanal anastomosis. More recently, the Transanal Transection and Single Staple anastomosis (TTSS) technique has been described. The TTSS technique has the potential to mitigate the difficulties encountered with DST and the potential complications and long-term functional sequalae encountered with handsewn anastomosis. Moreover, powered mechanical circumferential staplers represent a significant advancement in colorectal surgery, particularly in performing anastomosis following rectal excision. These devices are designed to provide consistent staple formation and controlled tissue compression, reducing the variability associated with manual stapling.

AL has a significant impact on clinical, patient-reported, and oncological outcomes. To mitigate the impact of AL a diverting stoma is routinely used to protect the distal anastomosis and facilitate anastomotic healing, with these stomas reversed once the integrity and patency of the distal anastomosis is confirmed. However, there is a significant complication profile associated with the routine use of diverting stomas. Through the incorporation of appropriate pre-operative risk stratification and careful post-operative surveillance a selective stoma strategy is associated with good clinical and functional outcomes.

The use of Double-stapled anastomotic technique (DST) or Transanal Transection Single-Stappled (TTSS) by laparoscopic or robotic approach, using or not a defunctionning stoma could not be separately tested in randomized trial.

In this exploratory, observational, prospective, IDEAL stage 2b International cohort study, we aim to include 400 patients with resection rectal and low powered colorectal anastomosis.

• Overall morbidity and mortality rates at 1 month [Time frame: At 1 month after the end of the surgery]
• The rate of anastomotic leakage at 6 and 12 months after rectal surgery; [Time frame: At 12 month after the end of the surgery]
• Quality of life with QLQ C30 questionnaire [Time frame: At 1, 6 and 12 months after rectal surgery]
• Quality of life with QLQ CR29 questionnaire [Time frame: At 1,6 and 12 months after rectal surgery]
• Qualiy of life with EQ5D-5L [Time frame: At 1, 6 and 12 months after rectal surgery]
• Digestive function with LARS score [Time frame: At 1, 6 and 12 months after rectal surgery]
• Anal Incontinence with Wexner score ( or Vaizey score) [Time frame: At 1,6 and 12 months after rectal surgery]
• Female Sexual Function Index (FSFI) scale scores [Time frame: At 1, 6 and 12 months after rectal surgery]
• International Index of Erectile Function (IIEF)-5 [Time frame: At 1,6 and 12 months after rectal surgery]
• International Prostate Symptom Score (IPSS) [Time frame: At 1, 6 and 12 months after surgery]
• Predictive factors for anastomotic fistula [Time frame: From the surgery to 12 months]