A Clinical Trial Comparing Staged Turnbull-Cutait Pull-through Anastomosis With Direct Anastomosis Plus Prophylactic Ileostomy in the Treatment of Low Rectal Cancer After Internal Sphincter Resection

Laparoscopic surgery is recommended. A standard 5-port method is used to create pneumoperitoneum after placing the trocar. The sigmoid colon and upper rectal mesentery are dissected along Toldt's fascia. Autonomic nerves should be preserved, and high ligation of the inferior mesenteric vessels with lymph node dissection is recommended. TME: Using a posterior-to-anterior approach, the mesorectal plane is dissected down to the pelvic floor, cutting the Waldeyer's fascia to enter the intersphincteric space, where sharp dissection is carried out toward the levator ani muscle hiatus. The dissection endpoint is the dentate line, where the proximal colon is exteriorized by at least 2 cm and sutured to the anal canal with 6-8 stitches, without a protective ileostomy.Two to four weeks after the first surgery, after the colon has adhered well to the surrounding tissue, the exteriorized colon is excised (under epidural or spinal anesthesia, trimming the exteriorized colon to form the anus).

ISR is categorized into partial ISR (PISR), subtotal ISR, and total ISR (TISR). Correspondingly, the anastomosis site after coloanal anastomosis is located below the levator ani hiatus (PISR, near the dentate line; subtotal-ISR and TISR, below the dentate line).The dissection steps are the same as in the first stage of the Staged Turnbull-Cutait Pull-through Anastomosis group (TME and intersphincteric space dissection).The bowel is transected at least 1 cm below the tumor, leaving a larger segment of healthy tissue on the non-tumor side while ensuring that no more than 1/3 of the dentate line is resected to avoid impairing fecal control.Anastomosis is performed using absorbable sutures under direct visualization. A protective ileostomy is created 25-30 cm from the ileocecal valve.3 to 6 months after surgery, the ileostomy is reversed. Prior to closure, digital rectal examination, defecography, MRI, colonoscopy, and other evaluation must perform.