Effects of Modifying Hinotori Surgical Robot System on the Surgical Step of the Dissection of the Renal Hilum and the Kidney Isolation

The introduction of robot-assisted surgery using the da Vinci Surgical System (DVSS) has significantly advanced minimally invasive surgery in Japan. Subsequently, the hinotori Surgical Robot System (HSRS), the first domestically developed robot-assisted surgical system in Japan, was introduced in 2019 by Medicaroid Corporation (Kobe, Japan) cofunded by Sysmex Corporation and Kawasaki Heavy Industries (Kobe, Japan). The first procedure using the HSRS was robot-assisted radical prostatectomy (RARP), and the perioperative outcomes of its initial cases have been reported [1]. HSRS has also demonstrated effectiveness in robot-assisted partial nephrectomy (RAPN), robot-assisted radical nephrectomy, robot-assisted adrenalectomy, robot-assisted radical nephroureterectomy, and radical cystectomy [2-4]. Many surgeons first practiced and mastered robot-assisted surgery using DVSS, which was the first widely adopted system in Japan. For the HSRS, developed later, improving operability to enable surgeons to perform more sophisticated surgical techniques is a very important theme. One of the main advantages of the HSRS is its ease of modification. Our previous study demonstrated that modifications to the HSRS improved perioperative outcomes in RARP [5]. In this study, we report on the effects of HSRS modifications on specific surgical steps in kidney surgery. We retrospectively reviewed 57 cases who underwent RARN for kidney cancer or RANU for upper tract urothelial carcinoma, performed using the HSRS at Kobe University Hospital. We focused on the following modifications: reduction of arm floating sensation, mitigation of emergency stops during arm collisions, and the addition of a clutch function via hand switch in addition to the foot pedal. These modifications were previously shown to improve perioperative outcomes [5]. The patients who underwent RARN or RANU using the HSRS before these modifications were classified as Group A, and those treated after implementation as Group B. A comparison of patient backgrounds, surgeons experience, and perioperative outcomes between these groups are presented in Table 1. All RARN and RANU procedures were performed using a transperitoneal approach, following previously described standard surgical techniques [2, 3]. In total, 31 and 26 patients underwent RARN and RANU, respectively. Robot-assisted surgery was successfully completed in all cases, and no serious intraoperative mechanical malfunctions was observed. The number of surgeons with more experience as console (DVSS) or cockpit (HSRS) surgeons was significantly higher in Group A than in Group B. In addition, the time required for kidney isolation and renal hilum dissection were significantly shorter in Group B than those in Group A. There was no significant difference in dissection duration around the perirenal tissue. The Clavien-Dindo grade III complication rates in Groups A and B were 0% and 2.3%, respectively. Our findings indicate that HSRS modifications have enabled smoother surgical procedures for kidney isolation. While no significant difference in the time required before and after modification was observed in the perirenal dissection step—often assisted by the assistant—, the step involving renal hilum dissection, which demands precise handling and is primarily performed by the cockpit surgeon, was significantly expedited post-modification. This suggests HSRS modifications could improve surgical performance. Compared with the DVSS, the HSRS differs in several aspects, including its instrument repertoire, sense of levitation, viewing angles, and sensitivity to alerts and emergency stops during collisions. Many urologic surgeons who have mastered techniques on the DVSS may initially find these differences challenging However, the HSRS has the advantage that all joints are motor-driven and the system enables software-based modifications without changing the model. There are some limitations of this study. The sample size is small, and the influence of the difference of the surgeon's experience and surgical procedures such as “RANU or RARN” between two groups are inevitable. While taking these issues into consideration, our study suggests that HSRS modifications can reduce operations time not only in RARP but also in kidney surgeries such as RANU and RARN. Further improvements in HSRS operability are expected to further enhance surgical quality, even in more complex cases [6]. Jun Teishima: conceptualization, writing – original draft, investigation, data curation. Naoto Wakita: conceptualization, data curation. Kotaro Suzuki: data curation. Takuto Hara: data curation. Tomoaki Terakawa: data curation. Hideaki Miyake: conceptualization, writing – review and editing. The authors have nothing to report. The protocol for this research was approved by an optionally constituted ethics committee of the institution (Approval No. B250094) and it conforms to the provisions of the Declaration of Helsinki. Informed consent was waived due to the retrospective fashion. Jun Teishima belongs to an endowed chair funded by Medicaroid Corporation. Jun Teishima, Tomoaki Terakawa, and Hideaki Miyake are Editorial Board members of the International Journal of Urology and a co-authors of this article. To minimize bias, they were excluded from all editorial decision-making related to the acceptance of this article for publication.