TaTME Versus Open Intersphincteric Resection After Neoadjuvant Concurrent Chemoradiotherapy.

"laparotomy arm: surgical Instruments for open approach operation: Abdominal anterior resection combined with peranal intersphincteric resection of the rectum~Abdominal step a high ligation of the inferior mesenteric artery is performed together with a full mobilization of the left colon. A circular incision of the anal canal is performed 1 cm below the tumour. Both the mucosa and the muscular layer are incised to transect the internal anal sphincter. A coloanal anastomosis, transverse coloplasty or colonic J-pouch and a diverting loop ileostomy are associated with the hand-sewn coloanal anastomosis.~laparoscopic approach group: instruments used: laparoscopic instruments mentioned at the arm description~intervention: laparoscopic mobilization of the rectum and colon combined with the peranal intersphincteric resection as in the laparotomy approach"

minimally invasive approach group: instruments used: laparoscopic instruments mentioned at the arm description instruments: laparoscopic instruments mentioned in the laparoscopic rectal resection arm intervention: laparoscopic mobilization of the rectum and colon combined with the peranal intersphincteric resection as in the laparotomy approach