Short-term surgical outcomes of robot-assisted colectomy for colon cancer using the hinotori Surgical Robot System

Koji Morohara; Hidetoshi Katsuno; Tomoyoshi Endo; Kenji Kikuchi; Kenichi Nakamura; Kazuhiro Matsuo; Takahiko Higashiguchi; Tetsuya Koide; Tsunekazu Hanai; Zenichi Morise

doi:10.3393/ac.2024.00871.0124

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Technical Note Minimally invasive surgery Short-term surgical outcomes of robot-assisted colectomy for colon cancer using the hinotori Surgical Robot System: Koji Morohara¹, Hidetoshi Katsuno¹, Tomoyoshi Endo¹, Kenji Kikuchi¹, Kenichi Nakamura¹, Kazuhiro Matsuo¹, Takahiko Higashiguchi¹, Tetsuya Koide¹, Tsunekazu Hanai², Zenichi Morise¹; Annals of Coloproctology 2025;41(1):97-103.
DOI: https://doi.org/10.3393/ac.2024.00871.0124
Published online: February 28, 2025

¹Department of Surgery, Okazaki Medical Center, Fujita Health University, Okazaki, Japan

²Department of Gastrointestinal Surgery, Fujita Health University Bantane Hospital, Nagoya, Japan

Correspondence to: Koji Morohara, MD, PhD Department of Surgery, Okazaki Medical Center, Fujita Health University, Gotanda 1, Harisaki, Okazaki 444-0827, Japan Email: koji.morohara@fujita-hu.ac.jp

• Received: November 27, 2024 • Revised: January 24, 2025 • Accepted: January 27, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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INTRODUCTION
TECHNIQUE
DISCUSSION
ARTICLE INFORMATION
SUPPLEMENTARY MATERIALS
REFERENCES

INTRODUCTION

Over the past 2 decades, advancements in robot-assisted surgery (RAS) have significantly improved surgical precision by providing capabilities that conventional laparoscopic surgery cannot offer. Key features—such as forceps with an extended range of motion, anti-shake technology, and high-resolution 3-dimensional (3D) imaging—have addressed many limitations of laparoscopic surgery [1, 2]. These innovations are particularly beneficial in rectal surgery, where precise manipulation within the narrow pelvic space is crucial [3, 4]. RAS is also expected to improve outcomes in laparoscopic colectomy.

The hinotori Surgical Robot System, developed by Medicaroid Corporation, is Japan's first domestically produced robotic surgery platform. Initially approved in 2020 for urological surgery, its application was extended to gastrointestinal and gynecological procedures by November 2022. However, reports on colectomy using the hinotori remain limited to case studies [5], and larger scale analyses are lacking. This study evaluates the short-term outcomes of RAS with the hinotori for colon cancer, focusing on its safety and feasibility.

TECHNIQUE

The hinotori system comprises an operation unit with 4 robotic arms, a surgeon cockpit, and a monitor cart (Fig. 1). Its robotic arms feature 8 axes, which provide enhanced flexibility while reducing interference. A monitoring system alerts the surgeon to potential collisions. Unlike conventional systems, the docking-free design enables pivot adjustments without linking the trocar to the robotic arms, thereby reducing tissue strain and increasing working space. The cockpit includes a 3D viewer to minimize neck strain (Fig. 1B) and a 16:9 wide monitor that offers enhanced visualization compared to da Vinci’s 4:3 monitor (Intuitive Surgical) [6].

Port placement for right and left hemicolectomies is illustrated in Fig. 2, while the setup for sigmoidectomy follows that used in robotic rectal surgery [7]. For procedures other than sigmoidectomy, a small laparotomy at the umbilicus facilitates instrument insertion. Lymph node dissection is performed using the D3 dissection technique combined with the double bipolar method [7].

The instrument configuration across the robotic arms includes bipolar forceps in arm 1 and an endoscope in arm 2, both of which remain stationary during surgery. Arms 3 and 4 accommodate interchangeable instruments tailored to specific surgical needs (Fig. 3). The docking-free design maintains unobstructed space around the trocars (Fig. 4A). During the medial-to-lateral approach, monopolar curved scissors assist in mobilization, and maryland bipolar forceps are used for lymph node dissection around vascular structures (Fig. 4B, C). After completing lymph node dissection and colonic mobilization, the robotic instruments are disengaged. Anastomosis is performed extracorporeally for ileocecal resection, right hemicolectomy, and left hemicolectomy, whereas for sigmoidectomy, the anastomosis is completed using the double-stapling technique.

Patients eligible for hinotori-assisted robotic colectomy included those with clinical stages I to IV colon cancer, excluding cases with tumors invading adjacent organs due to the system's early adoption phase. Clinical staging adhered to the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma, 9th edition [8]. In this study, 54 cases were analyzed; patient demographics and background are presented in Table 1. The median cockpit and total operative times were 135 minutes and 234 minutes, respectively, with minimal blood loss (median, 18 mL). Surgical procedures and outcomes are detailed in Table 2. Postoperative complications are listed in Table 3, which includes a single Clavien-Dindo grade III complication, an ileus requiring decompression with an intestinal tube. Pathological findings are summarized in Table 4, with a median of 26 harvested lymph nodes.

Ethics statement

The study was approved by the Institutional Review Board of Fujita Health University (No. HM24-029). Informed consent was waived due to the retrospective nature of the study. The study adhered to the ethical principles of the Declaration of Helsinki.

DISCUSSION

Recent technological advancements have demonstrated that RAS offers several advantages over laparoscopic surgery, particularly by improving short-term outcomes in rectal cancer treatment [9–11]. Looking ahead, RAS is expected to overcome many limitations of laparoscopic surgery and enhance the overall quality of colon cancer treatment. Meta-analyses have highlighted the benefits of robotic-assisted colectomy (RAC), including reduced conversion rates, faster return of bowel function, lower complication rates, decreased intraoperative blood loss, and shorter hospital stays [12, 13]. These advantages align closely with the findings of our current study.

Recent innovations in surgical robotic systems have been notable, with several new platforms gaining approval in Japan, including the hinotori [5, 7, 8, 14], the da Vinci SP (Intuitive Surgical), the Hugo RAS system (Medtronic), and the Saroa surgical robot (Riverfield Inc) [15]. The hinotori, which shares a similar structural design with the da Vinci system, has emerged as a more cost-effective alternative for institutions seeking to implement robotic surgery. However, reports on RAC using the hinotori remain limited. In both our previous study of 28 rectal cancer cases [7] and the current series of 54 colon cancer cases, no intraoperative complications, severe postoperative complications, or conversions to laparoscopic or open surgery were observed. These findings suggest that the hinotori is a safe and feasible surgical platform for colorectal cancer surgery.

A key difference between the hinotori and da Vinci systems is the hinotori’s docking-free mechanism, which eliminates the need to attach the trocar to the robotic arm. This design provides ample space around the trocar and reduces tissue damage from excessive traction. However, the hinotori requires a process called pivot setting, during which the system memorizes the trocar's position. If patient repositioning becomes necessary, the pivot must be reset, potentially extending operative time. Although this process may be time-consuming during the initial implementation phase, increased experience can significantly reduce the time required from the start of surgery to cockpit initiation—eventually shortening it to approximately 15 to 20 minutes. Another notable limitation is the absence of energy devices such as vessel sealing systems, ultrasonic coagulation shears, and linear staplers. To compensate, our facility primarily employs the double bipolar method [7], which has proven particularly effective for lymph node dissection procedures.

Although direct comparisons are challenging, our results indicate that the operative time with the hinotori was approximately 30 minutes longer than the operative times reported in meta-analyses of RAC [12, 13]. Nonetheless, blood loss was minimal, and no severe intraoperative complications were noted. The extended operative time may be attributed to the pivot resetting required during right and left hemicolectomies, as well as the limited availability of energy devices. Future developments aimed at simplifying the pivot setting process and expanding the range of energy devices are anticipated.

The hinotori demonstrates favorable short-term outcomes; however, challenges related to setup and operational complexities remain. As more cases accumulate, these issues are expected to be addressed, further improving the system's usability and efficiency. Further studies are necessary to evaluate long-term outcomes—including recurrence rates and survival—and to compare the hinotori with other robotic platforms such as the da Vinci. The cost-effectiveness of the hinotori also requires additional investigation. Although preliminary evidence suggests it may offer a more affordable alternative to the da Vinci, comprehensive cost-benefit analyses are needed to support these claims and inform healthcare policy decisions. As robotic surgery evolves, ongoing innovation and increased competition among platforms are likely to drive further technological advancements and cost reductions. The hinotori represents a significant achievement in Japan's medical technology sector and has the potential to contribute meaningfully to the global development of RAS.

In conclusion, this study demonstrates that RAC using the hinotori yields favorable short-term surgical outcomes, confirming its safety and technical feasibility in colon cancer surgery. However, to fully evaluate the long-term efficacy and broader clinical impact of the hinotori, further studies with larger patient cohorts and extended follow-up are essential. Future research should prioritize long-term outcomes, such as recurrence rates and overall survival, to more definitively establish the role of the hinotori in colorectal cancer treatment.

ARTICLE INFORMATION

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Funding

None.

Acknowledgments

The authors thank Medicaroid Corporation for providing the photographic images used in this publication.

Author contributions

Conceptualization: K Morohara, HK, T Hanai; Investigation: K Morohara, HK, TE, KK, KN, K Matsuo, T Higashiguchi, TK; Methodology: K Morohara, HK, T Hanai, ZM; Project administration: K Morohara, HK, ZM; Supervision: HK, T Hanai, ZM; Visualization: K Morohara, HK; Writing–original draft: K Morohara; Writing–review & editing: all authors. All authors read and approved the final manuscript.

SUPPLEMENTARY MATERIALS

Supplementary Video 1.

Left hemicolectomy using the hinotori Surgical Robot System (Medicaroid Corp).

Supplementary materials are available from https://doi.org/10.3393/ac.2024.00871.0124.

Fig. 1.

The hinotori Surgical Robot System (Medicaroid Corp). (A) The operation unit is equipped with 4 robotic arms, each possessing 8 axes to provide greater flexibility in movement. (B) The surgeon cockpit is equipped with a flexibly positioned 3-dimensional viewer, designed to reduce neck and shoulder fatigue. (C) Monitor cart. Images courtesy of Medicaroid Corporation.

Fig. 2.

Arrangement of surgical instruments and port placement for (A, B) right hemicolectomy and (C, D) left hemicolectomy. A rigid endoscope was attached to arm 2.

Fig. 3.

The 4 robotic arms of the hinotori Surgical Robot System (Medicaroid Corp). (A) Arm 1: fenestrated bipolar forceps in the left hand. (B) Arm 2: rigid 0° or 30° endoscope. (C–E) Arm 3: monopolar curved scissors, bipolar Maryland forceps, and clip applier in the right hand. (F, G) Arm 4: Croce grasping forceps or universal grasping forceps in the right hand. Images courtesy of Medicaroid Corporation.

Fig. 4.

Surgical technique of the hinotori Surgical Robot System (Medicaroid Corp). (A) A docking-free system is presented, providing ample space around the trocars and minimizing tissue damage caused by excessive traction. (B) Lymph node dissection in ileocecal resection using the double bipolar method. (C) Lymph node dissection in left hemicolectomy using the double bipolar method. ICV, ileocolic vein; SMV, superior mesenteric vein; IMA, inferior mesenteric artery; LCA, left colic artery; SA, sigmoid artery; SRA, superior rectal artery.

Table 1.

Patient demographics (n=54)

Characteristic	Value
Sex
Male	30 (55.6)
Female	24 (44.4)
Age (yr)	72 (38–85)
Body mass index (kg/m²)	22.7 (15.5–28.6)
ASA physical status
I	10 (18.5)
II	40 (74.1)
III	3 (5.6)
IV	1 (1.9)
Previous abdominal surgery	20 (37.0)
Tumor location
Cecum	8 (14.8)
Ascending colon	16 (29.6)
Transverse colon	4 (7.4)
Descending colon	9 (16.7)
Sigmoid colon	17 (31.5)
cStage
I	21 (38.9)
II	13 (24.1)
III	15 (27.8)
IV	5 (9.2)

Values are presented as number (%) or median (range).

ASA, American Society Anesthesiologists; cStage, clinical stage.

Table 2.

Operative outcomes

Outcome	Value
Type of procedure
Ileocecal resection	14 (25.9)
Right hemicolectomy	12 (22.2)
Left hemicolectomy	11 (20.4)
Sigmoidectomy	17 (31.5)
Lymph node dissection
D2	2 (3.7)
D3	52 (96.3)
Operative time (min)	234 (158–418)
Time to cockpit initiation (min)	23 (12–82)
Cockpit time (min)	135 (75–283)
Estimated blood loss (mL)	18 (2–391)
Conversion	0 (0)

Values are presented as number (%) or median (range).

Table 3.

Postoperative complications

Complication	Value
Clavien-Dindo grades I–II	4 (7.4)
Wound infection	2 (3.7)
Intra-abdominal infection	1 (1.9)
Ileus	1 (1.9)
Clavien-Dindo grade III (ileus)	1 (1.9)
Postoperative hospital stay (day)	9.5 (7–39)
Reoperation within 30 days of surgery	0 (0)
Readmission within 30 days of surgery	0 (0)

Values are presented as number (%) or median (range).

Table 4.

Pathological outcomes

Outcome	Value
Tumor size (mm)	30 (9–90)
pT category
pT1	13 (24.1)
pT2	12 (22.2)
pT3	20 (37)
pT4	9 (16.7)
pN category
pN0	42 (77.8)
pN1	6 (11.1)
pN2	6 (11.1)
pN3	0 (0)
pStage
I	23 (42.6)
II	18 (33.3)
III	8 (14.8)
IV	5 (9.3)
Lymph node retrieval	26 (6–67)
Proximal resection margin (mm)	97.5 (50–280)
Distal resection margin (mm)	100 (40–230)

Values are presented as median (range) or number (%).

pT, pathological T; pN, pathological N; pStage, pathological stage.

REFERENCES

1. Rondelli F, Balzarotti R, Villa F, Guerra A, Avenia N, Mariani E, et al. Is robot-assisted laparoscopic right colectomy more effective than the conventional laparoscopic procedure? A meta-analysis of short-term outcomes. Int J Surg 2015;18:75–82. Article PubMed
2. Yamauchi S, Hanaoka M, Iwata N, Masuda T, Tokunaga M, Kinugasa Y. Robotic-assisted surgery: expanding indication to colon cancer in Japan. J Anus Rectum Colon 2022;6:77–82. Article PubMed PMC
3. Kim MJ, Park SC, Park JW, Chang HJ, Kim DY, Nam BH, et al. Robot-assisted versus laparoscopic surgery for rectal cancer: a phase II open label prospective randomized controlled trial. Ann Surg 2018;267:243–51. Article PubMed
4. Mizoguchi M, Kizuki M, Iwata N, Tokunaga M, Fushimi K, Kinugasa Y, et al. Comparison of short-term outcomes between robot-assisted and laparoscopic rectal surgery for rectal cancer: a propensity score-matched analysis using the Japanese Nationwide Diagnosis Procedure Combination database. Ann Gastroenterol Surg 2023;7:955–67. Article PubMed PMC
5. Miyo M, Okita K, Okuya K, Ito T, Akizuki E, Ogawa T, et al. Right hemicolectomy for ascending colon cancer using the hinotori surgical robot system: the first ever case report for colon cancer. Asian J Endosc Surg 2023;16:604–7. Article PubMed
6. Inoue S, Nakauchi M, Umeki Y, Suzuki K, Serizawa A, Akimoto S, et al. First clinical experiences of robotic gastrectomy for gastric cancer using the hinotori^TM surgical robot system. Surg Endosc 2024;38:1626–36. Article PubMed PDF
7. Katsuno H, Morohara K, Endo T, Chikaishi Y, Kikuchi K, Nakamura K, et al. A new era in surgical oncology: preliminary insights into the hinotori^TM surgical robot system's role in rectal surgery using the double bipolar method. World J Surg Oncol 2024;22:215.Article PubMed PMC PDF
8. Japanese Society for Cancer of the Colon and Rectum. Japanese classification of colorectal, appendiceal, and anal carcinoma: the 3d English edition [secondary publication]. J Anus Rectum Colon 2019;3:175–95. Article PubMed PMC
9. Yamanashi T, Miura H, Tanaka T, Watanabe A, Goto T, Yokoi K, et al. Comparison of short-term outcomes of robotic-assisted and conventional laparoscopic surgery for rectal cancer: a propensity score-matched analysis. Asian J Endosc Surg 2022;15:753–64. Article PubMed PMC PDF
10. Matsuyama T, Endo H, Yamamoto H, Takemasa I, Uehara K, Hanai T, et al. Outcomes of robot-assisted versus conventional laparoscopic low anterior resection in patients with rectal cancer: propensity-matched analysis of the National Clinical Database in Japan. BJS Open 2021;5:zrab083.Article PubMed PMC PDF
11. Morohashi H, Sakamoto Y, Miura T, Ichinohe D, Kubota S, Yamazaki K, et al. Short-term outcomes of robotic-assisted surgery following neoadjuvant chemotherapy for lower rectal cancer. Asian J Endosc Surg 2022;15:577–84. Article PubMed PDF
12. Solaini L, Bazzocchi F, Cavaliere D, Avanzolini A, Cucchetti A, Ercolani G. Robotic versus laparoscopic right colectomy: an updated systematic review and meta-analysis. Surg Endosc 2018;32:1104–10. Article PubMed PDF
13. Solaini L, Bocchino A, Avanzolini A, Annunziata D, Cavaliere D, Ercolani G. Robotic versus laparoscopic left colectomy: a systematic review and meta-analysis. Int J Colorectal Dis 2022;37:1497–507. Article PubMed PMC PDF
14. Miura R, Okuya K, Akizuki E, Miyo M, Noda A, Ishii M, et al. World-first report of low anterior resection for rectal cancer with the hinotori^TM Surgical Robot System: a case report. Surg Case Rep 2023;9:156.Article PubMed PMC PDF
15. Hanaoka M, Kinugasa Y, Sakai Y, Tokunaga M. World’s first report of sigmoidectomy for sigmoid cancer using the Saroa surgical system with tactile feedback. Updates Surg 2023;75:2395–401. Article PubMed PDF

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Short-term surgical outcomes of robot-assisted colectomy for colon cancer using the hinotori Surgical Robot System

Ann Coloproctol. 2025;41(1):97-103. Published online February 28, 2025

DOI: https://doi.org/10.3393/ac.2024.00871.0124

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Figure

Short-term surgical outcomes of robot-assisted colectomy for colon cancer using the hinotori Surgical Robot System

Fig. 1. The hinotori Surgical Robot System (Medicaroid Corp). (A) The operation unit is equipped with 4 robotic arms, each possessing 8 axes to provide greater flexibility in movement. (B) The surgeon cockpit is equipped with a flexibly positioned 3-dimensional viewer, designed to reduce neck and shoulder fatigue. (C) Monitor cart. Images courtesy of Medicaroid Corporation.

Fig. 2. Arrangement of surgical instruments and port placement for (A, B) right hemicolectomy and (C, D) left hemicolectomy. A rigid endoscope was attached to arm 2.

Fig. 3. The 4 robotic arms of the hinotori Surgical Robot System (Medicaroid Corp). (A) Arm 1: fenestrated bipolar forceps in the left hand. (B) Arm 2: rigid 0° or 30° endoscope. (C–E) Arm 3: monopolar curved scissors, bipolar Maryland forceps, and clip applier in the right hand. (F, G) Arm 4: Croce grasping forceps or universal grasping forceps in the right hand. Images courtesy of Medicaroid Corporation.

Fig. 4. Surgical technique of the hinotori Surgical Robot System (Medicaroid Corp). (A) A docking-free system is presented, providing ample space around the trocars and minimizing tissue damage caused by excessive traction. (B) Lymph node dissection in ileocecal resection using the double bipolar method. (C) Lymph node dissection in left hemicolectomy using the double bipolar method. ICV, ileocolic vein; SMV, superior mesenteric vein; IMA, inferior mesenteric artery; LCA, left colic artery; SA, sigmoid artery; SRA, superior rectal artery.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Short-term surgical outcomes of robot-assisted colectomy for colon cancer using the hinotori Surgical Robot System

Characteristic	Value
Sex
Male	30 (55.6)
Female	24 (44.4)
Age (yr)	72 (38–85)
Body mass index (kg/m²)	22.7 (15.5–28.6)
ASA physical status
I	10 (18.5)
II	40 (74.1)
III	3 (5.6)
IV	1 (1.9)
Previous abdominal surgery	20 (37.0)
Tumor location
Cecum	8 (14.8)
Ascending colon	16 (29.6)
Transverse colon	4 (7.4)
Descending colon	9 (16.7)
Sigmoid colon	17 (31.5)
cStage
I	21 (38.9)
II	13 (24.1)
III	15 (27.8)
IV	5 (9.2)

Outcome	Value
Type of procedure
Ileocecal resection	14 (25.9)
Right hemicolectomy	12 (22.2)
Left hemicolectomy	11 (20.4)
Sigmoidectomy	17 (31.5)
Lymph node dissection
D2	2 (3.7)
D3	52 (96.3)
Operative time (min)	234 (158–418)
Time to cockpit initiation (min)	23 (12–82)
Cockpit time (min)	135 (75–283)
Estimated blood loss (mL)	18 (2–391)
Conversion	0 (0)

Complication	Value
Clavien-Dindo grades I–II	4 (7.4)
Wound infection	2 (3.7)
Intra-abdominal infection	1 (1.9)
Ileus	1 (1.9)
Clavien-Dindo grade III (ileus)	1 (1.9)
Postoperative hospital stay (day)	9.5 (7–39)
Reoperation within 30 days of surgery	0 (0)
Readmission within 30 days of surgery	0 (0)

Outcome	Value
Tumor size (mm)	30 (9–90)
pT category
pT1	13 (24.1)
pT2	12 (22.2)
pT3	20 (37)
pT4	9 (16.7)
pN category
pN0	42 (77.8)
pN1	6 (11.1)
pN2	6 (11.1)
pN3	0 (0)
pStage
I	23 (42.6)
II	18 (33.3)
III	8 (14.8)
IV	5 (9.3)
Lymph node retrieval	26 (6–67)
Proximal resection margin (mm)	97.5 (50–280)
Distal resection margin (mm)	100 (40–230)

Table 1. Patient demographics (n=54)

Values are presented as number (%) or median (range).

ASA, American Society Anesthesiologists; cStage, clinical stage.

Table 2. Operative outcomes

Values are presented as number (%) or median (range).

Table 3. Postoperative complications

Values are presented as number (%) or median (range).

Table 4. Pathological outcomes

Values are presented as median (range) or number (%).

pT, pathological T; pN, pathological N; pStage, pathological stage.