Application of the Xi robotic platform for familial adenomatous polyposis with ultra-low rectal cancer: exploration of minimally invasive and refined therapies

When a familial adenomatous polyposis (FAP) patient’s rectal polyp undergoes malignant transformation, the surgeon needs to consider how to balance the quality of surgery with the patient’s quality of life. Here, we present a case of robotic surgery in a patient with familial adenomatous polyposis and ultra-low rectal cancer. Fiberoptic colonoscopy found that hundreds of polyp-like bulges were diffusely distributed throughout the colon, and a malignant mass was found at the end of the rectum. The patient underwent total colectomy with abdominoperineal extended radical resection for rectal cancer using the Xi robotic platform. The patient recovered well in the postoperative period. The ileostomy was well used. And the patient was in good health and metastasis free at 9 months postoperatively. We identified total colectomy combined with extended radical rectal resection under the assistance of the da Vinci robot platform is of great benefit to the patient.


Introduction
Surgical treatment is an important part of the lifelong surveillance for familial adenomatous polyposis (FAP) [1]. The robotic platform is well recognized in segmental colectomy or total mesorectal excision surgery [2,3]. Here, we reported the first case of applicating the Xi robotic platform for familial adenomatous polyposis with ultra-low rectal cancer.

Case report
A 29-year-old man with a family history of FAP was diagnosed with FAP by colonoscopy. Colonoscopy revealed hundreds of polypoid protrusions throughout the colon and rectum. A big lesion was found at 1 cm from the anus, which was pathologically reported as adenocarcinoma. The preoperative staging of rectal cancer was mrT2N0, and the whole-body computed tomography scan suggested no distant metastases. The American Society of Anesthesiologists classification was class II and his body mass index was 19.3 kg/m 2 . The patient expressed a strong desire for anus preservation. The multidisciplinary team comprehensively evaluated the patient's condition and the rectal lesion location, and decided to perform a total colectomy combined with abdominoperineal extended radical resection for rectal cancer using the Xi robotic platform.

Surgical position, trocar placement and surgical procedure
Gastrointestinal preparation was performed 12 h before surgery. After anesthesia, the patient was placed in a modified lithotomy position. This procedure is performed using a four-port approach as shown in Fig. 1A. The four trocars are placed in the umbilical region, in the right iliac fossa, Huan Xiong and Jiaqi Wang have equally contributed to this work and shared the frst authorship.

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and in the right and left upper quadrants. The surgeon separated the end of the ileum and the whole colon in turn, and finally performed abdominoperineal extended radical resection for rectal cancer (Fig. 1B, C). The position of the manipulator was adjusted according to different surgical sites.

Anatomical separation of the colon
The two operating arms of the robot system are connected to Trocar R1 and Trocar R2, with Trocar A acting as a manual auxiliary hole. The right hemicolectomy and left hemicolectomy were performed using the lateral approach. In a clockwise direction, the surgeon separated the lateral ascending colon in turn, free and ligated the vessels feeding the right hemicolon in turn. Then, the omentum is opened and the gastrocolic ligament is severed. The terminal ileum was divided with an Echelon ENDOPATH stapling. (Fig. 1D) After reorienting the camera to target the splenic flexure of the colon, the surgeon divided the lateral descending colon, then opened the Toldt's fascia and sequentially dissected the left colic artery and the left branch of arteriae colica media. At this point, the dissection of the terminal ileum, ascending, transverse and descending colon has been completed.

Abdominoperineal resection for rectal cancer
For rectal cancer resections, the orientation of the camera was adjusted to target the pelvic cavity. The patient was adjusted to the Trendelenburg position [4]. The operation arms were connected to Trocar A and Trocar R2, with Trocar R1 acting as a manual auxiliary hole. The surgeon performed total mesorectal excision with D3 lymph node dissection of the mesenteric lymph nodes. After completed removal of rectum and anal from the perineum, the surgeon extracted the disconnected partial ileum, total colon, rectum and anal canal through the perineal incision (Fig. 1E). After the perineal assistants left two drains in the presacral space and sutured the perineal incision, the surgeon closed the pelvic floor peritoneum (Fig. 1F). Sterile saline peritoneal lavage was performed.

Digestive tract reconstruction
After extending the incision of Trocar A, the surgeon pulled the ileal dissection out of the abdominal wall and The left colon and rectum were dissected sequentially. D The terminal ileum was divided with an Echelon ENDOPATH stapling; E the partial ileum, total colon, rectum and anal canal which had been disconnected were pulled out through the perineal incision; F closed the pelvic floor peritoneum; G photographs of patients' abdominal walls; H photographs of surgical specimens performed a single-lumen ileostomy. The remaining three trocar holes were closed (Fig. 1G).

Postoperative outcomes
The operative time was 100 min for free right colon, 85 min for free left colon, and 210 min for abdominoperineal rectal cancer radical surgery and ileostomy. The blood loss was only 50 ml. Patients resumed flatus via stoma at 36 h postoperatively, and gradually resumed liquid nutrient on the third day postoperatively. The pathology of the local rectum reported rectal cancer staged as AJCC stage III (pT2N1M0), moderately differentiated adenocarcinoma, invaded dentate line, and negative circumferential resection margin. The number of detected lymph nodes was 21 with 1 positive finding. Multiple tubular adenomas were detected in the whole colon, but pathological analysis of them was not performed, because the number of tubular adenomas reached hundreds (Fig. 1H).

Follow-up data
The patient refused genetic testing but received mFOLFOX6 adjuvant chemotherapy. At 3 months postoperatively, the QLQ-C30 questionnaire of the patients suggested good functional scores and symptom scores consistent with previous studies [5]. The patient was in a healthy condition at six months postoperatively. The patient stated that his urinary and sexual functions were not negatively affected, and no stoma-related complications occurred.

Discussion
When FAP patients are complicated with locally advanced colorectal cancer, the surgical approach should be determined by the stage and location of colorectal cancer [6]. For this patient, despite earlier preoperative MRI staging, the rectal tumor was located too close to the anus. We finally decided to perform total colectomy and abdominoperineal extended radical resection for rectal cancer.
Surgical safety and quality are usually priorities. In this case, we applied the da Vinci robotic surgical system to perform total colectomy with abdominoperineal extended radical resection for rectal cancer for the first time. Compared with laparoscopic total colorectal resection undergone by patients with conventional FAP, the present procedure required an extended radical treatment of rectal cancer, but the total length of each step did not increase significantly [7]. In addition, the surgeon was able to complete the resection of the colon more quickly with the robotic surgical system, thus attacking the lower rectum with greater concentration. The robotic surgical system has a clearer and broader field of vision and more stable operating arms, which are helpful for the surgeon to identify the subtle nerves and blood vessels in the pelvis and prevents the surgeon from accidentally injuring the nerves and blood vessels due to arm tremors [3].
In addition, the patient had a good perioperative recovery without any complication such as abdominal hemorrhage, respiratory infection, and abdominal abscess occurred. The patient's short-term quality of life and psychological status were at a high level and the urinary and reproductive were not affected by the surgery. This indicates that the procedure was of high quality.
We did not open the specimen in the abdominal cavity or removed the specimen transabdominally. All surgical specimens were removed via the perineum, which is also a NOSES-like procedure [8]. The pathological report of invaded dentate line justified our choice of abdominoperineal radical resection. The lymph node dissection in this procedure is above standard. And the negative circumferential resection margins further demonstrate the radicality of the procedure. Accordingly, the procedure was in accordance with the aseptic and tumor-free principle.
There are still some challenges with this procedure. Due to financial constraints, we lacked the assistance of an additional robotic arm, which prolonged the operative time compared to previous reports [9,10]. The surgical scope of the patient involved the whole colorectum, and the rectal cancer needed to be radically resected. In addition, the position and orientation of the robotic arms were changed during the procedure, which may have resulted in additional operative time. The risks of anesthesia associated with prolonged operation should be seriously concerned. Therefore, we recommend this type of procedure for suitable patients in large general hospitals and do not recommend its widespread promotion.
In conclusion, with the assistance of the Xi robotic platform, the perioperative outcomes and short-term outcomes of four-port approach for total colectomy combined with extended rectal radical resection are excellent. This case was only an initial exploration, and more clinical studies are required in the future to confirm the safety and feasibility of the procedure. versions of the manuscript. All authors read and approved the final manuscript.
Funding None.
Data availability All data and information are saved in the Second Affiliated Hospital of Harbin Medical University, and the information is true, credible and available. The datasets is availability from the corresponding author on reasonable request.