Surgical Robot-Assisted Transanal Specimen Extraction Radical Sigmoidectomy Without an Auxiliary Abdominal Incision

This clinical study represents a robotic-assisted radical sigmoidectomy resection with a transanal specimen extracted without a auxiliary abdominal incision. The proposal and the refinement of NOSES concept represent a major technological innovation in the field for minimally invasive surgery. Robot-assisted NOSES integrates the advantages of robotic surgery with natural orifice specimen extraction, ensuring radical resection efficacy while significantly enhancing both the surgeon's experience and the patient's recovery.

To begin, use nanocarbon to mark the site of the primary tumor during preoperative colonoscopy. After tilting the patient to displace the small intestines away from the surgical site, use small gauze to prevent the intestines or mesentery from sliding and interfering with the surgical field. Grasp and lift the rectum and inferior mesenteric vessels ventrally with two forceps to expose the surgical area.

Use bipolar coagulation forceps to open tilt space at the sacral promontory. Push along tilt space and dissect to the right iliac vessel bifurcation. Dissect the presacral space from proximal to distal using sharp and blunt techniques.

Increase the grasping force for the mesentery and use sharp and blunt dissection to gradually expose and widen the space. Gently draw the mesentery pedicle to the left ventral side using grasping forceps and expand the peritoneal window using bipolar coagulation forceps. Expose the root of the inferior mesenteric artery and separate it distally along its direction.

Then progressively isolate the left colic artery, the sigmoid artery, and the superior rectal artery. Dissect the lymph nodes at the root of the inferior mesenteric artery. Expose and ligate the sigmoid artery, superior rectal artery and inferior mesenteric vein in sequence.

Place gauze on the posterior aspect of the mesosigmoid to protect the ureter end vessels. Pull the sigmoid mesentery to the right to expose the mesentery peritoneum junction. Dissect the lateral attachments of the sigmoid colon free.

Completely mobilize the sigmoid colon using sharp and blunt dissection. Incise the sigmoid mesocolon to the bowel edge and ligate the sigmoid vessels along the dissection line. Clear parasigmoid fat and epiploica for two to three centimeters along the bowel.

Ensure the distal resection margin is five centimeters from the tumor. Dissociate the mesentery along the same horizontal line from right to left. Connect the resection lines posteriorly.

Select a protective sleeve appropriate to specimen size. Then insert it through trocar hole A1, placing it in the abdominal cavity for later use. Transect the rectum at the lower resection line using an endoscopic linear cutter.

Then sterilize the cut ends of the intestine with povidone gauze. Use bipolar forceps to carefully expose the rectal stump and disinfect with iodoform gauze. Ask the assistant to press an iodoform gauze against the stump using an oval clamp to generate tension.

Hold the oval clamp and carefully draw the transparent protective sleeve through the anus to create a sterile passage. Then insert the anvil through the protective sleeve into the abdomen. Make a longitudinal incision on the exposed sigmoid colon above the tumor.

After disinfecting the lumen, insert the anvil into the lumen of the proximal sigmoid colon. Then use the linear cutter to close the incision while leaving the anvil in place. Disinfect the stump with povidone gauze.

Protrude the center rod of the anvil head through one side of the suture line. Place the resected specimen and any used gauze into the sterile plastic sleeve before extracting them through the anus. Then carefully tighten the protective sleeve to secure the contents.

Insert an oval clamp into the pelvic cavity through the anus and grasp one end of the specimen. Gently extract it through the rectum and anus. Confirm that the protective sleeve remains intact.

Close the open rectal stump using a linear cutter. Then place the closed stump in a specimen bag and remove it through trocar A1.Introduce the circular stapler through the gently dilated anus. Protrude the spike of the stapler from one side of the suture line.

Connect the center rod of the anvil to the distal part of the circular stapler. Check for twisting of colon and mesentery and ensure surrounding organs are away from the stapling path. Perform a reinforced suture at the intraabdominal risk triangle.

Check the anastomosis for leaks by verifying the proximal and distal ring integrity and performing an air test. Place two drainage tubes routinely on either side of the pelvic cavity at the anastomosis site. The sigmoid colon specimen was surgically resected with no signs of perforation or fragmentation.

Histopathology following surgery showed no residual cancer in the sigmoid colon with reactive lymphadenopathy observed in all 12 retrieved lymph nodes. The patient underwent blood index examinations on the first, third and fifth postoperative days, as well as in the fourth week after surgery to monitor changes in hemoglobin levels, inflammation markers, and liver function. The surgeon rated intraoperative workload was minimal with all NASA-TLX dimension scores at or near the lowest rating of one to two.