Robot‐assisted low anterior resection in a patient with rectal cancer who had a urinary reservoir: A case report

Undergoing another surgery after a previous abdominal procedure can sometimes result in significant abdominal adhesions. We present a case of robot‐assisted low anterior resection in a patient with rectal cancer who had a urinary reservoir. A 65‐year‐old male patient underwent robot‐assisted total bladder resection and creation of a urinary reservoir for bladder cancer in 2013. He presented with melena. Thus, the findings revealed advanced low rectal cancer. The robot‐assisted low anterior resection was performed in 2022. Extensive adhesions were observed in the pelvic space. The indocyanine green function was appropriately used, and the robotic surgery was completed without injury to the urinary reservoir or major complications. The surgical time was 510 min, and the blood loss volume was 15 mL. The patient had been recurrence free for 12 months following the surgery. Robot‐assisted surgery can be beneficial for patients with rectal cancer with significant pelvic adhesions.


| INTRODUCTION
Total mesorectal excision (TME) is the fundamental strategy in rectal cancer (RC) surgery.However, surgery in patients with RC who have a prior history of pelvic surgery can be challenging due to the disruption of normal dissection planes and membrane structures in the anterior rectal wall, thereby increasing the surgical difficulty. 1 In Japan, the use of surgical assistance robots was sanctioned under the Pharmaceutical Affairs Law in 2009, and for the first time, it was included in insurance coverage for complete prostatectomy in 2012.This was followed by coverage for rectal surgery in 2018 and extended to all colorectal cancers in 2022.A recent study has shown that robotic surgery is linked to fewer positive circumferential resection margins and perioperative complications when compared with conventional laparoscopic surgery in advanced RC. 2 However, the benefit of robotic surgery for RC with associated adhesions remains uncertain.We present a case of robot-assisted low anterior resection (LAR) in a patient with RC patient who has a history of abdominal surgery.

| CASE PRESENTATION
A 65-year-old male patient had a preexisting bladder cancer (underwent robotic total bladder resection and urinary reservoir reconstruction).The cancer was first diagnosed in 2013.In 2022, he presented with melena.Therefore, the lower gastrointestinal endoscopy revealed a tumor in the lower rectum, and the patient was diagnosed with RC.The blood test revealed low hemoglobin levels (11.2 g/dL) and normal tumor marker levels (carcinoembryonic antigen level: 3.0 ng/mL and cancer antigen 19-9 level: 28.4 IU/L).The lower gastrointestinal endoscopy revealed a 50-mm large type 2 lesion in the lower rectum with 7.0 cm from the anal verge.The biopsy revealed tubular adenocarcinoma (tub1 and tub2) (Figure 1).The computed tomography scan and magnetic resonance imaging revealed contrast enhancement in the rectum and the urinary reservoir located anterior to the rectum (Figure 2).Based on these findings, a clinical diagnosis of cT3, cN1b, cM0, and cStage IIIB according to the Union for International Cancer Control classification, eighth edition in the lower rectum was made.Thus, robot-assisted LAR and colostomy were performed.The Da Vinci Xi surgical system (Intuitive Surgical Inc.) was attached to an 8 mm port, which was positioned at the navel and used as a camera port targeting the sigmoid-descending junction.Two 8 mm ports were inserted in the lower right abdomen and one 8 mm port was placed in the upper left abdomen.We used a fenestrated bipolar forceps for port 1, a camera for port 2, a curved monopolar scissors for port 3, and a tip-up fenestrated grasper for port 4.
The surgical findings revealed extensive adhesions within the abdominal cavity.The small intestine, which was being used as a urinary reservoir, was adhered to the abdominal wall and the sigmoid colon.(Figure 3).The mesentery that supplies the sigmoid colon, the urinary reservoir, and the replacement bladder was challenging to handle due to adhesions.Indocyanine green (ICG) at the lower margin of the tumor facilitated the resection of the rectal tumor through TME, confirming the replacement bladder and the ureteral and urethral anastomoses of the replacement bladder (Figure 4).After establishing a 3 cm margin on the anorectal surface of the rectum and performing dissection, an anastomosis was created using the double stapling technique.The surgical time was 510 min, the console time was 375 min, and the volume of blood loss was 15 mL.There were no intraoperative complications.

| DISCUSSION
After bladder resection, one of the urinary tract reconstructions involved creating a urinary reservoir using the small intestine.The replacement bladder was located on the anterior wall of the rectum.Consequently, the dissected layer of the TME was compromised during surgery.The peeling layer of the TME was damaged.Additionally, a significant adhesion has formed between the urinary reservoir and the rectum.
In addition to the necessary oncological healing properties required for standard RC surgery, bladder function must be preserved.Given that the surgery for TME in patients with RC was performed in a narrow pelvic cavity, the open or laparoscopic procedure can be an extremely challenging one.Robotic surgery features high-definition threedimensional imaging and antishake, multijoint, and motion scaling functions.3][4] Previous reports have shown that in robotic surgery, there is no significant difference in perioperative outcomes, even in cases with a history of abdominal surgery compared with cases with no history of abdominal surgery. 1,5,6The tips for adhesiotomy include using stable forceps operation and the multijoint functionality of robotic surgery, which enables precise removal by identifying the appropriate separation layer between adhesions.
Additionally, robotic surgery features a Firefly fluorescence imaging function using ICG, which is used to assess lymphatic and blood flow, as well as to verify lymph node dissection and blood flow at the anastomosis site. 7Using these functions, even highly complex surgeries can be performed safely. 8,9Hasegawa et al. showed that robotic surgery is beneficial for procedures such as pelvic kidney surgery, where the surgical field of view is obstructed by organs, especially due to the ability to eliminate the physical interference of the forceps thanks to their articulated function. 10Moreover, in our case, the benefits of using ICG were especially valuable.The local injection into the mucosa near the tumor not only pinpointed the tumor but also highlighted the lymphatic vessels within the mesorectum.However, the border between the mesorectum and the small mesentery used for the urinary reservoir was not well defined.
We report the case of a patient who had a prior history of bladder replacement due to bladder cancer.Robot-assisted surgery for patients with RC can also be beneficial in cases with significant pelvic adhesions.conducted in accordance with the principles of the Helsinki Declaration.

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I G U R E 1 Lower gastrointestinal endoscopic image.There was a 50-mm large type 2 lesion in the lower rectum with 7.0 cm from the anal verge.The biopsy revealed tubular adenocarcinoma (tub1, tub2).

F I G U R E 2
Computed tomography (CT) scan.A contrast effect was observed in the rectum, and the urinary reservoir (white arrow) was located anterior to the rectum.Magnetic resonance imaging (MRI).The urinary reservoir (white arrow) was located anterior to the rectum, with a high degree of adhesion expected.Rectal cancer (black arrow) in contact with the urinary reservoir.F I G U R E 3 Representative intraoperative images.Extensive adherence of the urinary reservoir (UR) to the right side of the rectal wall and the anterior wall.