{"paper_id":"60c190a6-2231-4755-bc36-62eab78dc625","body_text":"Review began\n 01/20/2026 \nReview ended\n 02/09/2026 \nPublished\n 02/11/2026\n© Copyright \n2026\nMabuchi et al. This is an open access\narticle distributed under the terms of the\nCreative Commons Attribution License CC-\nBY 4.0., which permits unrestricted use,\ndistribution, and reproduction in any\nmedium, provided the original author and\nsource are credited.\nDOI:\n 10.7759/cureus.103434\nFeasibility and Safety of Robotic Para-Aortic\nLymphadenectomy Using the hinotori™ Surgical\nRobot System: A First-in-Human Experience\nSeiji Mabuchi \n, \nTomoyuki Sasano \n, \nTomoko Ueda \n, \nYu Wakimoto \n, \nHiroshi Tsubamoto \n1.\n Department of Obstetrics and Gynecology, Hyogo Medical University, Nishinomiya, JPN\nCorresponding author: \nSeiji Mabuchi, \nseijimabuchi@hyo-med.ac.jp\nAbstract\nThis case series reports the first cases of para-aortic lymphadenectomy performed using the hinotori™\nSurgical Robot System (Medicaroid Corporation, Kobe, Japan), Japan’s first domestically developed robotic\nsurgical platform. Three patients with gynecologic malignancies (two endometrial and one ovarian cancer)\nunderwent curative surgery, including total hysterectomy, bilateral salpingo-oophorectomy, pelvic\nlymphadenectomy, and para-aortic lymphadenectomy. All procedures were completed robotically without\nconversion or intraoperative complications. Operative time ranged from 461 to 512 minutes, and blood loss\nfrom 10 to 50 mL. A total of 9-38 para-aortic lymph nodes (median 26) were retrieved, comparable to yields\nfrom laparoscopic or da Vinci®-assisted procedures, confirming oncologic adequacy. Postoperative recovery\nwas uneventful in all cases. These cases demonstrate that para-aortic lymphadenectomy using the\nhinotori™ system is technically feasible and safe. Expanding its use from well-established pelvic surgery to\nadvanced oncologic procedures marks an important milestone for robotic surgery in Japan. Further studies\nare needed to refine protocols and assess outcomes.\nCategories:\n Obstetrics/Gynecology\nKeywords:\n abdominal aorta, endometrial neoplasms, lymph node excision, ovarian neoplasms, para-aortic\nlymphadenectomy, robotic surgical procedures\nIntroduction\nPara-aortic lymphadenectomy (PALND) plays a crucial role in the surgical staging and therapeutic decision-\nmaking of gynecologic malignancies, where para-aortic lymph node metastasis is a key prognostic factor \n[1]\n.\nWhile its definitive survival benefit remains under investigation, several randomized controlled trials (RCTs)\nare ongoing to determine its therapeutic impact \n[2-4]\n. Traditionally, this procedure was performed via\nlaparotomy, which is associated with significant surgical trauma and delayed postoperative recovery due to\nthe large abdominal incision. With increasing patient demand for minimally invasive options and rapid\ntechnological advances, minimally invasive approaches, including laparoscopy and robot-assisted surgery,\nhave gained popularity \n[5,6]\n. Minimally invasive PALND requires a high level of technical skill and\nexperience, as the procedure is performed within a narrow operative field adjacent to major vessels,\nincluding the inferior vena cava, aorta, and renal vessels, and carries potential risks of vascular, uterine, and\nintestinal injury. In this context, robot-assisted surgery may offer advantages over open surgery, including\nenhanced three-dimensional visualization, improved ergonomics, and tremor filtration, potentially enabling\nsafer and more precise dissection in a narrow retroperitoneal space. However, to date, all reported cases of\nrobot-assisted PALND have been performed using the da Vinci® system \n[5,6]\n.\nThe hinotori™ Surgical Robot System is a novel robotic-assisted surgical platform developed in Japan by\nMedicaroid Corporation (Kobe, Japan), a joint venture between Kawasaki Heavy Industries and Sysmex\nCorporation. It became the first domestically developed robotic system to gain regulatory approval in Japan\nin August 2020. The system features a surgeon console and a patient-side cart with four robotic arms, each\nwith eight degrees of freedom, enhancing flexibility and reducing arm collision. Its software-based pivot\ncalibration and ergonomic design aim to optimize performance and surgeon comfort \n[7]\n. Clinical use began\nin 2020 in urology \n[8]\n, later expanding to gastrointestinal, thoracic, and gynecologic surgeries \n[9]\n. In\ngynecology, it has mainly been applied to endopelvic surgeries for benign uterine diseases and early-stage\nendometrial cancer \n[10]\n. Importantly, PALND using the hinotori™ system has never been reported in any\nsurgical specialty.\nHere, we present the world’s first cases of PALND performed using the hinotori™ system in patients with\nendometrial or ovarian cancer, evaluating its safety, feasibility, and perioperative outcomes, in the context\nof previously published da Vinci®-based experiences.\nCase Presentation\nSurgical procedures\n1\n1\n1\n1\n1\n \nOpen Access Case Report\nHow to cite this article\nMabuchi S, Sasano T, Ueda T, et al. (February 11, 2026) Feasibility and Safety of Robotic Para-Aortic Lymphadenectomy Using the hinotori™\nSurgical Robot System: A First-in-Human Experience. Cureus 18(2): e103434. \nDOI 10.7759/cureus.103434\n\nPatient and Ethical Considerations\nThree patients with gynecologic malignancies requiring full staging surgery, including PALND, were\nenrolled. All provided written informed consent. Procedures were approved by the High-Level New Medical\nTechnology Evaluation Committee of Hyogo Medical University Hospital and performed as self-financed\nmedical care. The Institutional Review Board waived the requirement for approval, as a case series of three\npatients did not meet the definition of human-subject research.\nInstrument Placement\nTrocar placement for PALND is shown in Figure \n1A\n. The abdomen was entered via the open technique, and a\n12-mm balloon trocar was placed infraumbilically. Three 8-mm robotic trocars were positioned horizontally\nbelow the umbilicus, and an additional 8-mm assistant port was placed in the lower quadrant to maintain\npneumoperitoneum at 12 mmHg using an AirSeal® system (CONMED Corporation, Largo, FL). The patient\nwas placed in a 20° Trendelenburg. Small bowel and omentum were retracted cranially before docking. The\nhinotori™ cart was docked from the right for PALND, and then undocked and rotated for pelvic procedures\n(Figure \n1B\n). Perioperative prophylaxis included intravenous flomoxef and low-molecular-weight heparin.\nFIGURE\n 1: Positioning of the trocars.\n(A) Trocar placement for para-aortic lymphadenectomy (PALND). (B) Trocar placement for pelvic surgery.\nOriginal illustration created by the authors.\nSurgical Technique\nPALND was generally performed up to the level of the renal vessels using a transperitoneal approach, as\npreviously reported \n[11]\n. However, in technically challenging cases - such as those with severe adhesions,\nvascular anomalies, or marked obesity - the dissection was limited to the level of the inferior mesenteric\nartery (Figure \n2\n). Key steps included: (1) incision of peritoneum over the right common iliac artery; (2)\ncreation of peritoneal tent through a suspension of the peritoneum using Laptraction® (Hakko Co., Ltd.,\nNagano, Japan) \n[12]\n; (3) lateral retraction of the right ureter with a silicone sling (Vespasta®; Alfresa Pharma\nCorporation, Osaka, Japan) \n[13]\n; (4) identification of renal vein, psoas muscle, inferior mesenteric artery,\ngonadal vein, and a left ureter; (5) dissection of nodes from aortic bifurcation to renal veins; and (6) removal\nof presacral nodes. Specimens were extracted via the 12-mm port or vaginally.\n \n2026 Mabuchi et al. Cureus 18(2): e103434. DOI 10.7759/cureus.103434\n2\n of \n7\n\nFIGURE\n 2: Extent of para-aortic lymphadenectomy.\nCase 1: Para-aortic lymphadenectomy (PALND) to the level of the inferior mesenteric artery (IMA). Cases 2 and 3:\nPALND to the level of the left renal vein.\nOriginal illustration created by the authors.\nThe clinicopathological characteristics and the surgical outcomes of three cases undergoing para-aortic\nlymphadenectomy using the hinotori™ Surgical Robot System are summarized in Table \n1\n.\n \n2026 Mabuchi et al. Cureus 18(2): e103434. DOI 10.7759/cureus.103434\n3\n of \n7\n\n　\n　\nCase 1\nCase 2\nCase 3\nAge (year)\n72\n62\n70\nBody mass index (kg/m\n2\n)\n18.2\n17.5\n19.6\nFamily history of hereditary cancer\nNo\nNo\nNo\nChief complaint\nAbnormal uterine bleeding\nAbdominal distension\nAbnormal uterine bleeding\nCancer type\nEndometrial cancer\nOvarian cancer\nEndometrial cancer\nHistology\nEndometrioid adenocarcinoma\n(grade 2)\nMucinous\nadenocarcinoma\nEndometrioid adenocarcinoma\n(grade 3)\nPreoperative stage\nIB\nIB\nIB\nSurgical procedures\nSH, BSO, PLND, PALND, OM\nPLND, PALND\nPLND, PALND, OM\nIndication for surgery\n†\nStaging for stage IB disease\nStaging for stage IB\ndisease\nStaging for stage IB disease\nOperative time (minutes)\n477\n461\n512\nBlood loss (mL)\n25\n50\n10\nTotal lymph nodes\n25\n66\n46\nPelvic lymph nodes\n16\n28\n20\nPara-aortic lymph nodes\n9\n38\n26\nMetastatic lymph nodes\n0\n0\n0\nIntraoperative/Postoperative\ncomplications\nNo\nNo\nNo\nPostoperative adjuvant\nchemotherapy\nAP\nNo adjuvant\nAP\nRecurrence (Follow-up duration)\nNo (14 months)\nNo (6 months)\nNo (3 months)\nTABLE\n 1: Clinicopathological characteristics of three cases of para-aortic lymphadenectomy\nusing the hinotori™ Surgical Robot System.\n†\nStaging of endometrial and ovarian cancers was performed according to the 2009 and 2014 International Federation of Gynecology and Obstetrics\nclassifications, respectively.\nSH, simple hysterectomy; BSO, bilateral salpingo-oophorectomy; PLND, pelvic lymphadenectomy; PALND, para-aortic lymphadenectomy; OM,\nomentectomy; AP, adjuvant chemotherapy consisting of doxorubicin plus cisplatin\nCase 1\nA 72-year-old woman (BMI 18.2 kg/m\n2\n) with grade 2 endometrioid adenocarcinoma, clinically suspected to\nbe stage IB disease, underwent robotic total hysterectomy, bilateral salpingo-oophorectomy (BSO), pelvic\nlymphadenectomy (PLND), and PALND up to the inferior mesenteric artery (Figures \n2\n, \n3\n). The operative time\nwas 477 minutes, with an estimated blood loss of 25 mL. Final pathology revealed pT1B N0 M0 disease\n(grade 2 endometrial carcinoma) with lymphovascular invasion. A total of 25 lymph nodes were retrieved (16\npelvic and 9 para-aortic). She received adjuvant chemotherapy and remained disease-free at 12 months of\nfollow-up.\n \n2026 Mabuchi et al. Cureus 18(2): e103434. DOI 10.7759/cureus.103434\n4\n of \n7\n\nFIGURE\n 3: Intraoperative views after completion of para-aortic\nlymphadenectomy.\nRepresentative photographs from three cases. The para-aortic lymphadenectomy included the lateroaortic,\npreaortic, laterocaval, precaval, aortocaval, and presacral regions, extending from the level of the inferior\nmesenteric artery (Case 1) or the left renal vein (Cases 2 and 3) to the aortic bifurcation.\nAo, descending aorta; IMA, inferior mesenteric artery; IVC, inferior vena cava; Lumb A, lumbar artery; Ov vein,\novarian vein; Ure, ureter\nCase 2\nA 62-year-old woman (BMI 17.5 kg/m\n2\n) with a large mucinous ovarian tumor, initially suspected to be a\nmucinous borderline tumor, underwent primary open surgery including total hysterectomy, BSO, and\nomentectomy. However, final pathology confirmed invasive carcinoma. Subsequently, robotic restaging\nsurgery was performed, including PLND and PALND up to the renal vessels (Figures \n2\n, \n3\n). The operative time\nwas 461 minutes, and blood loss was 50 mL. A total of 66 lymph nodes were removed (28 pelvic and 38 para-\naortic), all of which were negative. The patient opted for observation without adjuvant therapy and\nremained recurrence-free at four months.\nCase 3\nA 70-year-old woman (BMI 19.6 kg/m\n2\n) with grade 3 endometrial carcinoma, clinically suspected to be stage\nIB disease, underwent robotic total hysterectomy, BSO, omentectomy, PLND, and PALND up to the renal\nvessels (Figures \n2\n, \n3\n). The operative time was 512 minutes, with minimal blood loss of 10 mL. Final\npathology demonstrated pT1A N0 M0 disease (grade 3 endometrial carcinoma) without lymphovascular\ninvasion. A total of 46 lymph nodes were retrieved (20 pelvic and 26 para-aortic), all negative. She is\ncurrently receiving adjuvant chemotherapy.\nDiscussion\nThis study was designed as an exploratory, early-phase investigation to address the question of whether\nPALND can be technically performed using the hinotori™ Surgical Robot System. Accordingly, we reported a\ncase series comprising the first three patients who underwent hinotori™-assisted PALND at our institution. \nAs of 2024, four robotic platforms have been approved in Japan: da Vinci® (2009), Hugo™ (2020), Saroa™\n(2022), and hinotori™ (2023). To date, only the da Vinci® system has been reported for use in PALND \n[14]\n.\nBarriers to wider adoption of hinotori™ include its recent approval and the absence of insurance\nreimbursement for robotic PALND, unlike laparoscopic PALND.\nTo our knowledge, this is the first study to demonstrate the feasibility and safety of PALND performed using\nthe hinotori™ Surgical Robot System, a domestically developed robotic platform in Japan. These findings\nsuggest that the hinotori™ system may be applicable to advanced gynecologic oncologic procedures beyond\nendopelvic surgery and could provide an additional option for institutions in Japan where the system is\navailable.\nIn our three cases, 9-38 para-aortic nodes were retrieved, comparable to or exceeding the 6-33 nodes\ntypically reported for laparoscopic or da Vinci®-assisted PALND \n[14,15]\n, suggesting an oncologic adequacy.\nNo conversions or intraoperative complications occurred, and blood loss was minimal (10-50 mL),\nconfirming safety. Postoperative recovery was uneventful in all cases, supporting feasibility. Operative times\n(461-512 minutes) were also consistent with Japanese reports (371-834 minutes, median ~480) \n[14]\n. The\nrelatively lengthy operative times reflect the academic training environment, where junior surgeons\nperformed pelvic procedures, including hysterectomy, salpingo-oophorectomy, and pelvic\nlymphadenectomy, while the most experienced surgeon performed the PALND. Operative times are expected\n \n2026 Mabuchi et al. Cureus 18(2): e103434. DOI 10.7759/cureus.103434\n5\n of \n7\n\nto decrease as surgical proficiency increases.\nThe limitations of this study should be acknowledged. As this study was designed as a feasibility assessment\nrather than to validate therapeutic efficacy, this and the previous sections primarily focus on surgical\noutcomes, including operative time, blood loss, and perioperative complications. The number of retrieved\npara-aortic lymph nodes, one of the most important indicators of procedural adequacy in PALND, was\ncarefully evaluated and discussed in comparison with previously published reports. However, oncologic\noutcomes were not assessed because of the short follow-up duration and the limited number of cases.\nComparisons with laparoscopic or da Vinci®-assisted PALND were restricted to descriptive references based\non values reported in the literature, without statistical analysis or formal validation.\nWith further accumulation of cases, future studies will be able to address the limitations of the present\nreport and allow for more comprehensive evaluation of procedural safety, reproducibility, and oncological\nvalidity.\nConclusions\nPALND using the hinotori™ Surgical Robot System may be technically feasible in selected cases, with\nacceptable short-term perioperative outcomes. These first reported cases provide preliminary clinical\nexperience regarding the use of hinotori™ in oncologic surgery. Further accumulation of cases is necessary\nto clarify technical reproducibility and oncologic safety.\nAdditional Information\nAuthor Contributions\nAll authors have reviewed the final version to be published and agreed to be accountable for all aspects of the\nwork.\nAcquisition, analysis, or interpretation of data:\n  \nTomoyuki Sasano, Seiji Mabuchi, Tomoko Ueda, Yu\nWakimoto, Hiroshi Tsubamoto\nDrafting of the manuscript:\n  \nTomoyuki Sasano, Seiji Mabuchi\nCritical review of the manuscript for important intellectual content:\n  \nTomoyuki Sasano, Seiji Mabuchi,\nTomoko Ueda, Yu Wakimoto, Hiroshi Tsubamoto\nConcept and design:\n  \nSeiji Mabuchi\nSupervision:\n  \nSeiji Mabuchi\nDisclosures\nHuman subjects:\n Informed consent for treatment and open access publication was obtained or waived by all\nparticipants in this study. \nConflicts of interest:\n In compliance with the ICMJE uniform disclosure form, all\nauthors declare the following: \nPayment/services info:\n All authors have declared that no financial support\nwas received from any organization for the submitted work. \nFinancial relationships:\n All authors have\ndeclared that they have no financial relationships at present or within the previous three years with any\norganizations that might have an interest in the submitted work. \nOther relationships:\n All authors have\ndeclared that there are no other relationships or activities that could appear to have influenced the\nsubmitted work.\nReferences\n1\n. \nAlouini S, Bakri Y: \nPara-aortic lymphadenectomy in ovarian, endometrial, gastric, and bladder cancers: a\nsystematic review of randomized controlled trials\n. 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Int J Clin Oncol. 2025, 30:358-70.\n10.1007/s10147-024-02635-8\n15\n. \nDíaz-Feijoo B, Bebia V, Hernández A, et al.: \nSurgical complications comparing extraperitoneal vs\ntransperitoneal laparoscopic aortic staging in early stage ovarian and endometrial cancer\n. Gynecol Oncol.\n2021, 160:83-90. \n10.1016/j.ygyno.2020.10.038\n \n2026 Mabuchi et al. Cureus 18(2): e103434. DOI 10.7759/cureus.103434\n7\n of \n7","source_license":"CC0","license_restricted":false}