World-first report of low anterior resection for rectal cancer with the hinotori™ Surgical Robot System: a case report

Abstract

Background: The hinotori™ Surgical Robot System was approved for use in colorectal cancer surgery in Japan in 2022. This robot has advantages, such as an operation arm with eight axes, an adjustable arm base, and a flexible three-dimensional viewer, and is expected to be utilized in rectal cancer surgery. Herein, we report the world's first surgery for rectal cancer using the hinotori™ Surgical Robot System.

Case presentation: A 71-year-old woman presented to our hospital with bloody stools. A colonoscopy revealed type 2 advanced cancer in the rectum, and a histological examination exposed a well-differentiated adenocarcinoma. Abdominal enhanced computed tomography divulged rectal wall thickening without significant swelling of the lymph nodes or distant metastasis. Pelvic magnetic resonance imaging showed tumor invasion beyond the intrinsic rectal muscle layer. The patient was diagnosed with cStage IIa (cT3N0M0) rectal cancer and underwent low anterior resection using the hinotori™ Surgical Robot System. Based on an adequate simulation, surgery was safely performed with appropriate port placement and arm base-angle adjustment. The operating time was 262 min, with a cockpit time of 134 min. Subsequently, the patient was discharged 10 days postoperatively without complications. The pathological diagnosis was pStage IIA (cT3N0M0) and the circumferential resection margin was 6 mm.

Conclusions: We report the first case of low anterior resection for rectal cancer using the hinotori™ Surgical Robot System, in which a safe and appropriate oncological surgery was performed.

Keywords: Hinotori; Low anterior resection; Rectal cancer; Robotic surgery.

Fig. 1

Pre-operative colonoscopy examination. Colonoscopy reveals a type 2 tumor extending to almost the entire circumference of the rectum

Fig. 2

Pre-operative enhanced CT and MRI. A, B CT discloses wall thickening in the rectum (arrow). There are no enlarged lymph nodes or distant metastases (A: axial, B: sagittal). C MRI reveals tumor invasion beyond the intrinsic muscle layer of the rectum (arrow)

Fig. 3

Layout of the surgical instruments. The operating unit is rolled in from the left side of the patient and the tilt setting of the arm base is 6° to the lower right

Fig. 4

Port placement. A GelPOINT Mini (Applied Medical) is positioned at the umbilical site. R1–4 robotic arms; R1, R4 8 mm, R3 12 mm; and R2 port for the scope, 10 mm. Two assistant ports are placed on the upper right and lateral left sides of the abdomen

Fig. 5

Intra-operative findings during robotic low anterior resection. A The left colon is dissected using a medial approach. B Lymph nodes around the IMA are dissected and the root of the IMA is ligated. C The right side of the rectum is dissected. D The posterior rectum is dissected

Fig. 6

Intra-operative findings at the time of rectal transection. A The tumor is located endoscopically. B The rectum is dissected by the suturing device