Robot-assisted Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection for Locally Advanced Middle-low Rectal Cancer

The robotic technique described herein aims to detail a stepwise approach to robot-assisted total mesorectal excision, and lateral pelvic lymph node dissection for locally advanced rectal cancer located below the peritoneal reflection. This protocol complies with the guidelines of the Ethics Committee of the First Affiliated Hospital of Xi'an Jiaotong University. We present the case of a 64-year-old male patient who had intermittent hematochezia for approximately three months.

Digital rectal examination revealed that a mass was located on the interior and right lateral wall of the rectum, five centimeters from the anus. An enhanced computed tomography scan and endoscopic ultrasound revealed lower rectal cancer with internal iliac lymph node metastasis. Colonoscopic biopsy confirmed the presence of moderately differentiated adenocarcinoma.

Accordingly, we decided to perform a robot assisted total mesorectal excision, and lateral pelvic lymph node dissection. Patient consent was obtained prior to performing these procedures. Induce general anesthesia.

Place the patient in all Lloyd Davis position, and secure them carefully to the operating table. Ensure that the legs are carefully padded in stirrups, and that both arms are tucked at the side. Ensure that the primary surgeon operates from the robotic console, and customizes their settings.

Have an assistant laparoscopic surgeon stand on the right side of the patient. Have a nurse stand on the left side of the patient. Place the robotic, and assistant ports as depicted in figure.

Place each trocar after making transverse skin incision. Set visual port. Make a 12 millimeter incision 2 to 3 centimeters above of the umbilicus, and slightly to the left, and set a 12 millimeter trocar as a visual port.

Set three robotic arm ports. Place trocar after making transverse 8 millimeter skin incisions for each trocar. Place arm 1 in the right McBurney's point.

Place arm 2 in the midclavicular line at the level of the visual port. Place arm three in the left interior axillary line at the level of the visual port. Set two assistant ports.

Place a 12 millimeter assistant port 1 in the right midclavicular line at the level of the visual port. Place an 8 millimeter assistant port 2 approximately 1 to 2 centimeters above the pubic symphysis. Chapter three.

Total mesorectal excision. Section one. Mobilize the left colon.

Retract the descending and sigmoid colon medially by cardiere grasping forceps in R 3 to expose the left paracolic sulci. Release the physiological adhesions of the descending, and sigmoid colon along the paracolic sulci with monopolar scissors in R 1. Incise the peritoneum along the paracolic sulci.

Dissect the descending colon from superior to inferior with monopolar scissors in R 1 until the ureter is exposed to mobilize the lateral side of the descending, and splenic flexure colon. Place a piece sterile gauze near the ureter as an indicator. Grasp and keep elevating the sigmoid colon with its mesentery forward, using cardiere grasping forceps in R 3.

Tension the mesentery with a bipolar grasper in R 2, and forceps in the assistant's hand, then recognize the white line of Toldt's fascia. Incise the peritoneum along the white line. Separate along this plane toward the lateral paracolic sulci with monopolar scissors in R 1 to mobilize the sigmoid colon.

Afterwards, create a tunnel between the medial and a lateral compartments under the guidance of the indicator gauze that was set previously. Continue to develop this plane downward to the sacral promontory using electrocautery, and combined sharp, and blunt spreading to dissect rapidly to completely mobilize the descending and sigmoid colon. Section two.

Transect the inferior mesenteric artery and inferior mesenteric vein. After mobilizing the sigmoid colon, grasp, and keep elevating the sigmoid colon with forceps in R 3 to expose the aorta. Dissect along the aorta superiorly with monopolar scissors in R 1 to expose the inferior mesenteric artery.

Change the instrument in R 1 from monopolar scissors to harmonic scalpel. From the root of the inferior mesenteric artery, separate the lymphatic tissue from the vessel with an ultrasonic scalpel in R 1 until the left colic artery appears. Continue to separate the lymphatic tissue from the left colic artery with the harmonic scalpel in R 1.

Recognize the inferior mesenteric vein, and the descending branch of the left colic artery. Have the assistant surgeon clip the inferior mesenteric artery below the origin of the left colic artery with a large locking clip, then transect with the harmonic scalpel to minimize bleeding. Have the assistant surgeon clip, and transect the inferior mesenteric vein, and the descending branch of the left colic artery.

Section three. Perform pelvic dissection of the rectum. Use a ribbon retractor to lift the rectum.

Place the grasping forceps in A 2 by the assistant surgeon, and control the movement of the rectum by gripping the ribbon retractor. Change the instrument in R 1 to monopolar scissors. Lift the rectum forward with cardiere grasping forceps inserted through the posterior margin of sigmoid colon to expose the sacral promontory, then dissect into the retrorectal plane between the mesorectal fascia and pre-hypogastric nerve fascia with monopolar scissors in R 1.

Develop along this plane, and separate the mesorectal fascia from pre-hypogastric nerve fascia using monopolar scissor in R 1 until the level of the levator ani muscle is reached. Note, the integrity of the mesorectal fascia should be retained. Incise the peritoneum, and open the lateral mesorectal plane close to the rectum with monopolar scissors in R 1.

Have the assistant surgeon move the rectum to the other side. Change the instrument in R 1 to harmonic scalpel. Carefully dissect and develop this plane until the level of the levator ani muscle is reached.

Repeat this step for the contralateral side. If it seems difficult to operate consider dealing with the interior plane first. Incise the peritoneum 1 centimeter above the reflection of the visceral peritoneum with the harmonic scalpel in R 1.

After incising the reflection of the visceral peritoneum, identify the seminal vesicles and Denonvilliers'fascia that cover the posterior wall of the seminal vesicle. Continue to develop the plane between Denonvilliers'fascia and mesorectal fascia until the level of the levator ani muscle is reached with the harmonic scalpel in R 3. Note, in women, dissection should be performed between the vaginal posterior wall, and the mesorectal fascia.

Surgeons should avoid damaging the thin vaginal posterior wall. At this time, conduct a digital rectal examination trans anally to confirm that the dissection has proceeded past the distal margin of the tumor, and that there are appropriate margins for resection. Chapter four.

Lateral pelvic lymph node dissection. Starting on the left, incise the peritoneum just lateral to the ureter with the harmonic scalpel in R 1. Extend the incision up to the vas deferens.

Identify the left ureter at the level of its crossing with the iliac vessels, then mobilize the ureter and move it to the medial side with forceps in R 3. Avoid complete skeletonization of the ureter if possible. Let the ureter and pre-hypogastric nerve fascia become the medial plane of the lateral node dissection.

From the lateral to the external iliac artery, separate the lymphatic tissue surrounding the external iliac artery, and vein with the harmonic scalpel in R 1. Retract the external iliac vein laterally with the aspirator in the assistant's hand. At the bifurcation of the internal, and external iliac artery, separate lymphatic tissue with the harmonic scalpel in R 1, and identify the obturator nerve and umbilical artery.

At the lateral wall, completely release the lymphatic tissue from the surface of the psoas, and internal obturator muscles. Retract the umbilical artery, and the vesicle hypogastric fascia medially with the aspirator in the assistant's hand. Separate lymphatic tissue from the vesicle hypogastric fascia.

Let the umbilical artery and vesicle hypogastric fascia become the medial wall of dissection of obturator nodes. Carefully separate the lymphatic tissue from fascia and nerve along the obturator nerve with the harmonic scalpel in R 1, and identify the obturator artery and vein, which are the branches of the internal iliac artery and vein. Carefully isolate the obturator artery, and vein to avoid injury.

Retract the ureter and pre-hypogastric nerve fascia medially with the aspirator in the assistant's hand. Completely release the lymphatic tissue from fascia with a harmonic scalpel in R 1. Identify and isolate the 2 to 3 superior vesicle arteries which are the branches of the umbilical artery.

Avoid ligating all superior vesicle artery branches to minimize urinary dysfunction. At least one superior vesicle artery should be preserved especially when bilateral LPL and D is performed. Continue to dissect the lymphatic and fatty tissue distally with the harmonic scalpel in R 1, until meeting the vas deferens.

Remove the lymphatic adipose tissue as a single specimen from the fossa using a sterile specimen bag. If necessary, repeat these steps on the right to complete the right side dissection. The procedure we present in video was performed in April, 2019, by the corresponding author using the DaVinci C robot system.

The estimated blood loss during the operation was 90 milliliters, and no transfusions were required. Post operative management adhered to the principles of enhanced recovery after surgery. After the first defecation on the sixth day after the operation, we administered a meglumine diatrizoate enema, and performed x-ray radiography to determine whether anastomotic leakage occurred.

We then removed the drain after confirming no evidence of leakage. The patient did not report any urinary or sexual dysfunction during follow up. The pathologic examination of the specimen indicated adenocarcinoma with moderate differentiation.

No positive lymph nodes were detected in any of the 19 mesorectal nodes or 18 lateral lymph nodes. We recommended that the patient receive adjuvant chemotherapy. Until January, 2021, the patient still remained without any evidence of recurrence or metastasis.

At our center, this robotic technique has been performed in 89 patients. All procedures were successfully completed under robotic assistance without conversion to open surgery. The detailed information is shown in table.

In conclusion, this robotic technique is safe, and feasible for patients with locally advanced middle low rectal cancer. This technique enables better exposure of complicated anatomic structures, and can reduce unanticipated injury. Following the development trend of minimally invasive surgery, an appropriate selection of surgical indications, and a radical understanding of anatomic structures are critical factors of successful procedures.

In addition, we suggest appropriately individualized adjustments based on the preferences, and experiences of individual surgeons.