Comparison of the efficacy of different models of KangDuo surgical robots and the da Vinci surgical robots in partial nephrectomy of RENAL score ≤9 tumors
Highlight box
Key findings
• This study included 124 patients who underwent robot-assisted partial nephrectomy (PN) and found that, when performed by experienced surgeons, different models of the KangDuo surgical robot system was comparable to the da Vinci system in key surgical outcomes, perioperative safety, and preliminary oncological results for tumors with a RENAL [radius (R), exophytic/endophytic (E), nearness to collecting system/sinus (N), anterior/posterior (A), and location relative to polar lines (L)] score ≤9.
What is known and what is new?
• Previous studies have shown that the safety and effectiveness of the KangDuo robotic system in renal surgery are non-inferior to those of the da Vinci system; however, most studies have focused on comparisons between single-generation models.
• This study found that the safety and effectiveness of the KangDuo and da Vinci robotic systems in PN are consistent across different models.
What is the implication, and what should change now?
• Different models of the KangDuo robot-assisted laparoscopic PN have comparable safety and effectiveness to the da Vinci robotic system for patients with renal tumors and a RENAL score ≤9.
Introduction
Renal cell carcinoma (RCC) is a common malignancy of the urinary system, with an annual global incidence of approximately 400,000 cases, imposing a substantial burden on patients’ quality of life and healthcare systems. For localized T1 renal tumors, partial nephrectomy (PN) has emerged as the standard kidney-sparing treatment (1). It achieves oncological outcomes comparable to radical nephrectomy while maximizing renal function preservation. Current surgical approaches primarily include open surgery, conventional laparoscopic surgery, and robot-assisted laparoscopic surgery. In recent years, with the continuous advancement of medical technology, robot-assisted laparoscopic surgery has been increasingly utilized in PN. This technique offers clear advantages over open surgery, such as lower estimated blood loss, fewer postoperative complications, and shorter hospital stays (2). Furthermore, when compared to traditional laparoscopy, robot-assisted laparoscopic surgery provides better ergonomics (3). Most current research focuses on the da Vinci surgical system. However, the high cost of the da Vinci system severely limits its widespread adoption in healthcare institutions.
In recent years, an increasing number of newly developed robotic surgical systems have entered the market, including Revo-I (4), Hugo (5), Senhance (6), and Hinotori (7). China has also developed a new surgical robot, the domestic KangDuo surgical robot system (KD-SR) (Suzhou KangDuo Robotics Co., Ltd., Suzhou, China). This system comprises a control console, a bedside surgical arm system, an image processing system, and surgical instruments. Its key features include an open-architecture console and a suspended bedside surgical arm system. With continuous technological upgrades and improvements, three models—SR-1000, SR-1500, and SR-2000—have been approved for market release sequentially. Currently, various models of the KangDuo system are being gradually adopted in a range of urological surgeries (8-10). Given this increasing clinical adoption, a systematic comparison is warranted. This study aims to compare the safety and efficacy of different KD-SR models with the da Vinci Surgical System in PN for tumors with a RENAL [radius (R), exophytic/endophytic (E), nearness to collecting system/sinus (N), anterior/posterior (A), and location relative to polar lines (L)] nephrometry score ≤9. We present this article in accordance with the TREND reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0476/rc).
Methods
General data
This prospective study collected clinical data from patients who underwent PN at Peking University First Hospital and its Miyun District branch between January 2024 and December 2025. From the initial cohort of 81 patients who underwent PN with the KangDuo Surgical Robot (KD-SR) system, 18 were excluded due to incomplete clinical data. Ultimately, 63 patients were included in the KD-SR group (Figure 1). Among these, 52 patients underwent PN with the KD-SR-1000 system, and 11 patients underwent PN with the KD-SR-2000 system. To establish a comparison group, we selected 61 patients who underwent da Vinci robotic PN during the same period. The da Vinci group was operated on by the same surgeon, who had performed the highest number of surgeries in the KD-SR group. This group comprised 46 patients who underwent PN with the da Vinci Si system and 15 patients who underwent PN with the da Vinci Xi system. All procedures were performed by expert surgeons from two large tertiary centers, each with experience in over 100 robotic surgeries.
Inclusion criteria: (I) requirement for PN [tumor-node-metastasis (TNM) stage T1, RENAL score ≤9]; (II) age 18–75 years, regardless of gender; (III) provided written informed consent for the surgical procedure. Exclusion criteria: (I) severe cardiac, pulmonary, cerebral, hepatic, or renal disease precluding tolerance of surgery or anesthesia; (II) inability to tolerate pneumoperitoneum; (III) severe coagulation disorders (activated partial thromboplastin time or prothrombin time exceeding 1.5 times normal range, or platelet count <100×109/L); (IV) active pulmonary tuberculosis.
This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Biomedical Research Ethics Committee of Peking University First Hospital (approval No. 2024 Yan 083-002). All patients in the KangDuo group provided written informed consent.
Data collection and definitions
We prospectively collected general clinical information and perioperative clinical data, including robotic operation time, warm ischemia time (WIT), estimated intraoperative blood loss, hemoglobin levels within 24 hours postoperatively, glomerular filtration rate, and positive surgical margin rate. Robotic console time was defined as the duration from the initiation of robotic instrument manipulation to the completion of the surgical procedure at the console.
The primary endpoint of this study is surgical success rate, defined as meeting all of the following criteria: (I) successful resection of the target lesion according to the predefined surgical plan with negative margins; (II) for RENAL scores of 4–6, intraoperative WIT <30 min; for RENAL scores of 7–9, intraoperative WIT <40 min; (III) no conversion to open surgery, radical resection, or laparoscopic procedures during surgery (8). Postoperatively, all adverse events were assessed using the Clavien-Dindo classification system.
Surgical procedure
The KD-SR-1000 is a master-slave robotic system comprising an open surgeon console, a three-arm robotic patient surgical platform, and an imaging cart (Figure 2A). The KD-SR-2000 adds a fourth arm to the KD-SR-1000 configuration (Figure 2B). Although both the KangDuo-2000 and da Vinci XI systems are 4-arm robots, we found that for PN, using just 3 robotic arms along with 2 assistant ports works better than using all four arms, resulting in a more efficient surgical workflow. Accordingly, all surgeries in this study were performed with just 3 arms. All patients underwent the same surgical procedure. The patient was positioned in the lateral decubitus position. The surgeon sat at the surgeon’s console (Figure 2C). Ports were placed as illustrated in Figure 3, and the same trocar layout was used for all patients. Subsequently, the docking process was performed. All patients underwent surgery via the transperitoneal approach. After dissecting the colon and exposing the renal artery (Figure 4A), the renal artery was clamped using a non-damaging Bulldog clamp (Figure 4B). The tumor was resected with a 0.5-cm margin of normal tissue (Figure 4C,4D). The surgical site was sutured with absorbable sutures (Figure 4E,4F). The tumor was then placed into a specimen bag for removal, and a drainage tube was inserted.
Patients are required to remain on bed rest for 1 day postoperatively. The urinary catheter is removed once the patient is able to ambulate. The surgical drain is removed approximately 3 days postoperatively, provided the drainage volume is less than 30 mL/day. Meanwhile, complete blood count (CBC), urinalysis, and liver and kidney function tests are reassessed on postoperative days 1 and 3. Once the drainage volume has decreased, laboratory results have returned to normal, and the patient’s condition is stable, the patient can be discharged.
Statistical analysis
Analysis was performed using SPSS 26.0 software. Normally distributed quantitative data are expressed as mean ± standard deviation. Comparisons between groups were conducted using t-tests. Non-normally distributed quantitative data are presented as median (interquartile range), and comparisons between groups were performed using nonparametric tests. Count data are expressed as frequencies or rates, and comparisons between groups were conducted using Chi-squared tests. Results were considered statistically significant when the P value was <0.05.
Results
General information
The baseline demographic and clinical characteristics were similar between the two groups, as shown in Tables 1,2.
Table 1
| Characteristics | KD-SR-1000 (n=52) | DV-SS-Si (n=46) | P value |
|---|---|---|---|
| Age (years) | 54.5 (43.3–61.8) | 56.5 (41.5–62.3) | 0.78 |
| Gender (male/female) | 33/19 | 33/13 | 0.38 |
| BMI (kg/m2) | 25.5 (23.7–27.7) | 25.2 (22.5–27.9) | 0.80 |
| Tumor location (right/left) | 29/23 | 21/25 | 0.31 |
| RENAL nephrometry score | 6.0 (5.0–7.0) | 6.5 (5.0–8.0) | 0.09 |
Data are presented as median (interquartile range) or n. BMI, body mass index; DV-SS-Si, da Vinci Si Surgical System; KD-SR-1000, KangDuo 1000 surgical robot; RENAL, radius (R), exophytic/endophytic (E), nearness to collecting system/sinus (N), anterior/posterior (A), and location relative to polar lines (L).
Table 2
| Characteristics | KD-SR-2000 (n=11) | DV-SS-Xi (n=15) | P value |
|---|---|---|---|
| Age (years) | 53.1±14.5 | 54.2±13.1 | 0.83 |
| Gender (male/female) | 2/9 | 1/14 | 0.38 |
| BMI (kg/m2) | 24.6±3.6 | 25.6±3.1 | 0.44 |
| Tumor location (right/left) | 8/3 | 12/3 | 0.15 |
| RENAL nephrometry score | 5.7±1.4 | 6.5±1.1 | 0.15 |
Data are presented as mean ± standard deviation or n. BMI, body mass index; DV-SS-Si, da Vinci Si Surgical System; KD-SR-2000, KangDuo 2000 surgical robot; RENAL, radius (R), exophytic/endophytic (E), nearness to collecting system/sinus (N), anterior/posterior (A), and location relative to polar lines (L).
Surgical information
In the KD-SR-1000 group, two patients had a WIT exceeding 40 minutes; the remaining patients completed their surgeries as planned. The robotic console time was significantly longer in the KD-SR-1000 and KD-SR-2000 groups than in the DV-SS-Si and DV-SS-Xi groups, respectively: 49.0 (41.3–60.0) vs. 40.5 (36.5–53.5) min (P=0.01) and (63.5±15.1) vs. (42.9±11.9) min (P<0.001). The operative time was significantly longer in the KD-SR-1000 and KD-SR-2000 groups than in the DV-SS-Si and DV-SS-Xi groups, respectively: 89.5 (73.3–112.3) vs. 72.0 (65.0–83.5) min (P<0.001) and (110.2±31.3) vs. (73.1±14.0) min (P<0.001). The postoperative hospital stay was also significantly longer in the KD-SR-1000 and KD-SR-2000 groups than in the respective control groups: 5.0 (4.0–7.0) vs. 3.0 (3.0–4.0) days (P<0.001) and 6.0 (5.0–6.0) vs. 3.0 (3.0–3.0) days (P<0.001). Additionally, the KD-SR-1000 group had significantly greater intraoperative estimated blood loss than the DV-SS-Si group [20 (20–50) vs. 20 (10–21) mL, P=0.01]. No significant differences were observed in the other indicators, as shown in Tables 3,4.
Table 3
| Variables | KD-SR-1000 (n=52) | DV-SS-Si (n=46) | P value |
|---|---|---|---|
| Primary outcomes | |||
| Success | 50 (96.2) | 46 (100.0) | 0.17 |
| Secondary outcomes | |||
| Conversions | None | None | – |
| WIT (min) | 15.5 (12.0–20.0) | 14.5 (11.0–19.0) | 0.13 |
| 30< WIT ≤40 min | None | None | – |
| WIT >40 min | 2 (3.8) | 0 | 0.17 |
| PSM | None | None | – |
| Console time (min) | 49.0 (41.3–60.0) | 40.5 (36.5–53.5) | 0.01 |
| Operative time (min) | 89.5 (73.3–112.3) | 72.0 (65.0–83.5) | <0.001 |
| EBL (mL) | 20.0 (20.0–50.0) | 20.0 (10.0–21.0) | 0.01 |
| Glomerular filtration rate reduced 24 hours after surgery (mL/min/1.73 m2) | 2.0 (–3.3 to 5.8) | 2.4 (–1.9 to 11.0) | 0.34 |
| Hemoglobin reduced 24 hours after surgery (g/L) | 12.0 (4.3–18.8) | 10.0 (6.0–17.0) | 0.50 |
| Postoperative hospital stay (days) | 5.0 (4.0–7.0) | 3.0 (3.0–4.0) | <0.001 |
Data are presented as median (interquartile range) or n (%). DV-SS-Si, da Vinci Si surgical system; EBL, estimated blood loss; eGFR, estimated glomerular filtration rate; KD-SR-1000, KangDuo 1000 surgical robot; PSM, positive surgical margin; WIT, warm ischemia time.
Table 4
| Variables | KD-SR-2000 (n=11) | DV-SS-Xi (n=15) | P value |
|---|---|---|---|
| Primary outcomes | |||
| Success | 11 (100.0) | 15 (100.0) | – |
| Secondary outcomes | |||
| Conversions | None | None | – |
| WIT (min) | 17.8±8.3 | 14.5±5.4 | 0.22 |
| 30< WIT ≤40 min | None | None | – |
| WIT >40 min | None | None | – |
| PSM | None | None | – |
| Console time (min) | 63.5±15.1 | 42.9±11.9 | <0.001 |
| Operative time (min) | 110.2±31.3 | 73.1±14.0 | 0.003 |
| EBL (mL) | 20.0 (10.0–150.0) | 20.0 (10.0–20.0) | 0.21 |
| Glomerular filtration rate reduced 24 hours after surgery (mL/min/1.73 m2) | 7.5±8.6 | 3.8±9.3 | 0.31 |
| Hemoglobin reduced 24 hours after surgery (g/L) | 9.8±11.6 | 9.9±7.3 | 0.99 |
| Postoperative hospital stay (days) | 6.0 (5.0–6.0) | 3.0 (3.0–3.0) | <0.001 |
Data are presented as n (%), mean ± standard deviation, or median (interquartile range). DV-SS-Xi, da Vinci Xi Surgical System; EBL, estimated blood loss; KD-SR-2000, KangDuo 2000 surgical robot; PSM, positive surgical margin; WIT, warm ischemia time.
Two patients in the KD-SR-1000 group and one patient in the KD-SR-2000 group received postoperative blood transfusions. One patient in the KD-SR-1000 group underwent interventional embolization therapy after surgery. All other patients in both groups experienced Clavien-Dindo grade I complications.
In the da Vinci Si group, there were 42 cases of RCC, 2 cases of angiomyolipoma, 1 case of posterior renal adenoma, and 1 case of complex renal cyst. In the da Vinci Xi group, there were 14 cases of RCC and 1 case of multilocular cystic renal tumor of low malignant potential. In the KD-SR-1000 group, there were 45 cases of RCC, 6 cases of angiomyolipoma, and 1 case of adrenal cortical adenoma. In the KD-SR-2000 group, there were 9 cases of RCC and 2 cases of angiomyolipoma.
Discussion
This study systematically conducted a subgroup analysis to compare two primary models of the domestically produced KD-SR system (SR-1000 and SR-2000) with two established models of the imported da Vinci surgical robot system (Si and Xi) in the context of PN for localized RCC. The KD-SR-2000 and da Vinci Xi robotic systems represent two new-generation platforms that offer enhanced operational flexibility of robotic arms, improved surgical visualization systems, and greater operator comfort compared to their predecessors. These advancements significantly improve the surgeon’s experience, as well as surgical precision and patient safety. All patients in this study underwent safe and successful procedures, with no conversions to open surgery or laparoscopic surgery. Our findings indicate no significant differences between the KangDuo system and the da Vinci system in key surgical outcomes and postoperative recovery metrics, such as WIT, positive surgical margin rate, and short-term postoperative renal function changes. The WIT in both groups was also comparable to that reported in previous clinical studies (8,9). Regarding perioperative outcomes, two patients in the KD-SR-1000 group and one patient in the KD-SR-2000 group received postoperative blood transfusions. One patient in the KD-SR-1000 group underwent interventional embolization therapy after surgery. All other patients in both groups experienced Clavien-Dindo grade I complications. These findings indicate that the safety and efficacy of the KD-SR system are comparable to those of the da Vinci system across different models. In a meta-analysis conducted by Almajali et al., no significant differences were observed between the KangDuo surgical robot and the da Vinci Surgical System in terms of efficacy or safety, suggesting comparable outcomes (11).
In this study, the KangDuo robot demonstrated longer operative time, console time and postoperative hospital stay compared to the da Vinci robot in both subgroups. We attribute the longer console time to potential differences between the two surgical robot systems: the da Vinci system employs an immersive visual system with manual clutch-based switching, whereas the KangDuo system employs an open visual system with foot-operated clutch controls only. Surgeons may require a learning curve to adapt to these differences, a finding consistent with prior observations in prostate cancer surgery (12). Additionally, the longer postoperative hospital stay in the KangDuo group likely stems from logistical or administrative factors, such as differing patient discharge protocols or bed availability across the hospital campuses where the KangDuo procedures were performed, rather than from differences in postoperative recovery itself.
In this study, the surgical success rate in the KD-SR-1000 group was 96.2%. The primary reason for the two cases with prolonged WIT was incomplete occlusion of branch vessels during surgery, which resulted in significant intraoperative bleeding. This compromised the surgical field during tumor resection, prolonging the WIT to 42 and 47 minutes, respectively. However, both patients completed the procedure successfully without conversion to open or laparoscopic surgery, and negative surgical margins were achieved. The KD-SR-1000 group exhibited significantly higher estimated intraoperative blood loss compared to the DV-SS-Si group. Specifically, we attribute this difference primarily to the incomplete occlusion of branch vessels in the aforementioned two patients, which substantially increased bleeding.
As an emerging robotic system, the KD-SR (including the KD-SR-1000 and KD-SR-2000 models) features an open console design that better aligns with ergonomic principles, allowing surgeons to adjust their seating position and neck posture according to personal preference during procedures, thereby reducing ocular and cervical fatigue (13). It also enables real-time comparison of intraoperative conditions with preoperative 3D reconstructions and fluorescence imaging (e.g., indocyanine green), which facilitates multimodal image fusion for decision-making without complex in-console image switching. However, like the da Vinci system, it lacks haptic feedback mechanisms. Furthermore, although both the KD-SR-2000 system and the da Vinci Xi surgical system are four-arm robots, we employed only three surgical arms in this study. We believe that using three surgical arms supplemented by two assistant ports facilitates more effective completion of the procedure compared to using four arms.
There are certain limitations in this study. First, although 124 patients were enrolled, the subgroups for the KD-SR-2000 and da Vinci Xi systems included relatively few patients. Furthermore, this study was not a randomized controlled trial. Future research should focus on conducting large-scale, multicenter, randomized controlled trials to validate these findings. Second, while we reported short-term oncological outcomes and renal function metrics, long-term tumor control (recurrence-free survival, overall survival) and renal function preservation require extended follow-up. Finally, this study primarily included patients with RENAL scores ≤9; consequently, it lacks comparative data on the safety and efficacy for highly complex renal tumors.
Conclusions
In summary, this study conducted a subgroup comparison between the domestically produced KD-SR system and the imported da Vinci surgical system for PN. The findings show that, when used by experienced surgeons, the KangDuo surgical robot system was not shown to be inferior to the da Vinci system in key surgical outcomes, perioperative safety, and preliminary oncological results for PN procedures of RENAL score ≤9 Tumors. However, the KangDuo group had longer operative time, console time, and postoperative hospital stay. The estimated intraoperative blood loss in the KD-SR-1000 group was significantly higher than that in the da Vinci Si group. This conclusion still requires validation by multicenter, prospective, randomized controlled trials with long-term follow-up.
Acknowledgments
None.
Footnote
Reporting Checklist: The authors have completed the TREND reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0476/rc
Data Sharing Statement: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0476/dss
Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0476/prf
Funding: This work was supported by
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0476/coif). X.L. serves as an Editor-in-Chief of Translational Andrology and Urology from March 2026 to March 2029. The other authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Biomedical Research Ethics Committee of Peking University First Hospital (Approval No. 2024 Yan 083-002). All patients in the KangDuo group provided written informed consent.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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