Laparoscopic Low Anterior Resection – A Stepwise Approach

Laparoscopic surgery is a technically demanding procedure that requires a significant level of experience and expertise. Since surgery is the mainstay treatment of rectal cancer, comprehending the complexities of multilaminar structures and interfascial spaces is imperative. This is the case of a 68-year-old woman who was evaluated for a positive fecal occult blood test. Colonoscopy found a vegetative lesion 15 cm from the anal verge, occupying ~1/2 of the lumen. Biopsy and distal tattooing were performed. Pathology study confirmed the presence of a moderately differentiated adenocarcinoma. The CT-scan showed no lung or liver metastasis. MRI revealed an upper rectal cancer, 11.4 cm from the anal verge, with no pathological lymph nodes, staged as cT2 N0 Mx CRM-. After discussion in a multidisciplinary meeting, a laparoscopic anterior rectal resection was proposed. By segmentation of the surgery into well-organized stages, this video demonstrates all the important technical steps to fasten the learning curve and master the procedure without compromising the oncologic principles.

The patient was put in a lithotomy position with a slight Trendelenburg (20 degree) and right lateral position (10 degree). This positioning allows the surgeon to use gravity as retraction for small bowel. The surgeon stood on the right side with the second assistant on the surgeon’s right side, while the first assistant was positioned on the left side of the patient. An umbilicus port was used to establish the pneumoperitoneum with a Veress needle. The surgery begins with the placement of four trocars. One 12 mm trocar at the umbilicus level to accommodate a 30-dregree camera and two working ports: a 12 mm trocar at the level of the right midclavicular line in right iliac fossa and a 5 mm trocar at the right para-umbilicus region in between the first two trocars, respectively. The first assistant placed another 5 mm trocar at the left para-umbilicus region aligned with the left midclavicular line as an auxiliary retraction port.

Exploratory Laparoscopy A diagnostic laparoscopy was performed to rule out any metastatic abdominal disease. Small Bowel Retraction The small bowel and the great omentum were placed in the right upper quadrant, out of the area of dissection. Preparation of the operative field is of the utmost importance in order to avoid small bowel overriding the dissection area. By retracting the uterus anteriorly, the pouch of Douglas is exposed allowing for the identification of the tattoo ink. Medial-to-lateral Dissection The sigmoid summit was retracted towards the anterior abdominal wall to put tension on the inferior mesenteric artery. This was followed by incising the peritoneum at the base of sigmoid mesocolon in a line starting at the sacral promontory. A space was then created between the mesocolon containing the arch of the inferior mesenteric artery and the posterior plane covered by Toldt’s fascia. Left Ureter and Gonadal Vessels Separation of the sigmoid mesentery from the retroperitoneal structures was done through entering into an avascular space below the inferior mesenteric artery. Dissection was directed upward just below the vessels and dropping down the gonadal vessels and the left ureter as they crossed the pelvic brim and travel downward into the pelvis. Inferior Mesenteric Artery Dissection then proceeded towards the origin of the inferior mesenteric artery, care being taken not to injure the sympathetic roots of dorsolumbar origin, which give rise to the superior hypogastric plexus located at the level of the sacral promontory. After the inferior mesenteric artery was dissected with the surrounding lymph nodes, ligation was achieved by ultrasonic energy after application of double proximal clips and a single distal one. Inferior Mesenteric Vein The next step was the identification, dissection, and distal cutting of the inferior mesenteric vein. Again, ultrasonic energy cutting was used after application of double proximal clips and a single distal one. Lateral Peritoneal Detachment After placing the gauze over the left ureter and gonadal vessels in order to avoid unintentional injury, the next step was freeing the lateral embryonic attachment between the peritoneum of anterior abdominal wall and the descending and sigmoid colon. The aim of this dissection was to reach the previously created retroperitoneal space. Peritoneal Reflection Pelvic dissection of the rectum was then carried out along the left side of the rectum moving anteriorly towards the peritoneum overlying the pouch of Douglas in women and the Denonvilliers’ fascia in men. The incision was completed on the right side of the rectum. Mesorectal Dissection In the pelvis, the dissection of the mesorectum started posteriorly at the sacral promontory with the rectum being pulled forwards and towards the head side. This dissection took place in the retrorectal space, also known as holy space, an avascular plane between visceral fascia and parietal fascia. By using a small gauze and an ultrasonic scalpel, surgeon’s dissection continued towards the pelvic floor. Dissection proceeded laterally and anteriorly until circumferential mobilization of the rectum was accomplished. [05:08min] Distal Margin Determination Then, surgeons proceeded to verify the location of the tumor and the distance between its inferior margin and the possible line of resection. Once determined, the distal transection cut is prepared by using an angled dissecting forceps and an ultrasonic scalpel. Through this dissection, surgeons aim to minimize the necessity for multiple linear stapler firings during rectal transection, thereby reducing the risk of anastomotic leakage. Since two or more firings are associated with a higher rate of anastomotic leak, surgeons should strive to reduce the number of linear stapler firings and try to transect the rectum with a single firing. [05:50min] Rectal transection The rectum was then transected with a 60mm linear stapler, blue cartridge. [06:06min] Tension free colon mobilization Since surgeons don’t routinely mobilize the splenic flexure, they initially ensured a tension-free anastomosis was possible due to the redundant colon. Here, one can see the proximal colonic segment was indeed long enough for a colorectal anastomosis at the level of the pelvic floor.   Mesocolon division In order to keep manipulation of the mesentery of the sigmoid colon to a minimum avoiding subsequent problems of tension or blood supply, proximal section of the vascular arcade was performed laparoscopically before specimen extraction to identify the level of proximal section of the colon. A Pfannenstiel incision was performed, dividing the proximal sigmoid colon externally. After placing the anvil of an end to end anastomosis circular stapler at the proximal colon, surgeons perfomed a purse string suture and dropped the colon into the abdomen.   End-to-End Anastomosis The rectum was irrigated with iodine solution and an assistant surgeon gently distended the anus digitally. After closing the Pfannenstiel incision and recreating the pneumoperitoneum, restoration of the bowel continuity was accomplished using a 29 mm end-to-end anastomosis circular stapler introduced from the anal canal. Leak Test The colonic and rectal doughnuts were inspected carefully, and a routine transanal air leak test was performed. Air leak test was done by injecting air in the anal canal and watching for bubbling in the pelvis flooded with irrigated saline solution.

The procedure was uneventful. The patient was discharged on postoperative day 5. The pathological examination confirmed the presence of a moderately differentiated adenocarcinoma with free margins. It was staged as pT3 N0 LV0 G2 R0 tumor, and the specimen had 20 lymph nodes without metastasis. The patient was referred to follow-up care and surveillance.

Recomendations: - A small gauze, besides maintaining control of minor oozing during the procedure, also allows for blunt dissection without the use of an energy source and sharp instruments. - The introduction of a vaginal manipulator by the assistant may help dissecting the anterior mesorectum from the vagina, lowering the risk of iatrogenic injury. - The positioning of the colon should be analyzed to avoid any twists in the mesentery. - A grasper may be placed distally at the transected rectum to serve as reference for the surgical specimen extraction.

No disclosure of conflicts.

I was unable to submit further authors that I would want to be included. I will leave here their name and remaining order: 2nd Inês Mogárrio Coelho MD 3rd Ana Sofia Oliveira MD 4th Diana Fernandes MD 5th Sofia Jardim Neves MD 6th Joana Vieira Pereira MD 7th Rómulo Ribeiro MD 8th Jorge Fernandes MD 9th Carmo Caldeira MD

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