2.5. Surgical technique

The surgical approach utilized for the NOSES group has been comprehensively elaborated in our prior work. ¹¹ Yet, to cater to the context of this investigation, a concise overview is presented below. Additionally, Figure 1 offers an illustrative depiction of the NOSES surgical procedure. For a more detailed and dynamic visual understanding, supplementary videos of each major step in the NOSES surgical procedure are available in the Supplementary Materials section (Supplementary Material 1).

Intra‐operative illustration of the NOSES surgical procedure. (A) Mobilization of the Descending and Sigmoid Colon. (B) Clipping of the inferior mesenteric artery using hem‐o‐lock clips. (C) Dissection of the mesorectum following total mesorectal excision (TME). (D) Delivery of the anvil in the sigmoid and resection of the rectum using the linear stapler echelon 60. (E) Removal of the anvil connection rod at the distal end of the sigmoid colon. (F) transanal extraction of the opened distal rectal stump for smooth specimen extraction. (G) Extracorporeal resection of the rectal specimen and inspection for adequate distal margin. (H) Passage of the head of the circular stapler through the anal orifice, followed by an end‐to‐end double‐stapled anastomosis. (I) positioning of the post‐operative peritoneal drainage tube near the anastomosis site. This figure provides a detailed intra‐operative depiction of the NOSES surgical procedure, illustrating the key steps involved in this minimally invasive approach to mid‐rectal surgery. (J) Three‐week postoperative assessment revealed favorable cosmetic results on the abdominal wall. Notably, the absence of additional incisional scars for specimen extraction was evident. Instead, five inconspicuous trocar scars were observed, contributing to excellent postoperative esthetic outcomes.

Patients underwent bowel preparation with oral laxatives and enemas. A single dose of either second‐generation Cephalosporins or Levofloxacin was administered intravenously during anesthetic induction, with repetition if surgery surpassed 3 hours. Post‐anesthesia, patients were positioned supine in a modified lithotomy stance. A five‐trocar laparoscopic method was employed. The tumor's location was then confirmed by a combination of digital rectal examination and intraoperative colonoscopy. The medial to lateral approach was utilized for mobilizing the descending and sigmoid colon, ensuring the preservation of the left gonadal vessels, left ureter, and inferior mesenteric nerve plexus. The inferior mesenteric artery was clipped using Hem‐o‐Lock clips (Teleflex Inc., USA) and transected. Lymph node dissection occurred at the root of the inferior mesenteric vessels. The mesorectum was dissected following the total mesorectal excision (TME) technique and was irrigated with 1% povidone‐iodine solution (Betadine®). The rectum was transected using a linear stapler (Echelon 60) 2‐3 cm below the tumor's lower edge. The distal rectum was then irrigated and incised for transanal specimen extraction. A sterile protective sleeve facilitated the specimen's extraction, ensuring no tumor deposition. The specimen was inspected extracorporeally, ensuring an adequate distal margin. The anvil of the circular stapler (CDH29) was introduced, followed by a purse‐string suture with 2–0 Prolene. The rectal stump was sealed with an Endo‐GIA linear stapler (AST45) and the specimen was retrieved. An end‐to‐end double stapled anastomosis was executed intracorporeally under laparoscopic guidance. Post‐operation, a peritoneal drainage tube was positioned near the anastomosis. The specimen's extraction through a natural orifice precluded the need for any additional abdominal incisions, thereby minimizing the risk of wound‐related complications.

Postoperatively, the exhaust time, which is the time to first passage of flatus or first bowel movement following surgery, was recorded. We also measured postoperative pain using the Visual Analogue Scale, which graded the pain intensity from 0 (no pain) to 10 (maximal pain ever experienced). ¹⁶

Conversely, the CLAR group underwent conventional laparoscopic‐assisted resection, wherein an abdominal incision was necessary for the specimen's extraction. This was followed by the same postoperative protocols as in the NOSES group.

By comparing these techniques, our study aims to highlight the advantages and disadvantages of each, thereby enabling a more informed choice of treatment for patients with mid‐rectal cancer.