Robot-assisted ureteral reimplantation using the KangDuo surgical Robot-01 system: a prospective, single-center, single-arm pilot study.

This prospective, single-center, single-arm clinical study complied with the Declaration of Helsinki (as revised in 2013). This study received approval from the Institutional Review Board of Peking University First Hospital (Beijing, China; IRB No. 2021SR338) and was registered on www.chictr.org.cn (ChiCTR2200056553). All patients provided written informed consent. From Feb. 2022 to Jun. 2024, 32 patients were recruited at Peking University First Hospital. The inclusion criteria for this study were as follows: (1) patients aged between 18 and 75 years; (2) confirmed diagnosis of distal ureteral stricture, vesicoureteral reflux or ureterovaginal fistula based on imaging; (3) had comprehensive preoperative data available. Exclusion criteria included concurrent malignancy, pregnancy and intolerance to surgery. All procedures were performed by a single surgeon who had completed more than 30 robotic pyeloplasty surgeries and partial nephrectomy surgeries in prior KD-SR-01 system trials and more than 50 robotic ureteral reimplantation using the da Vinci ® robotic system. The KD-SR-01 system is a master-slave robotic platform comprising a surgeon console, a 3-arm patient cart, and a high-definition vision cart (Fig.  1 a-c). The open surgeon console displays a 3D high-definition image on the primary screen and an auxiliary image on the secondary screen. The patient cart serves as the operating system, holding the endoscope and surgical instruments. The robot arm system mimics and precisely replicates the surgeon’s movements through the main hand controller and pedals. Fig. 1 The schematic diagram of KD-SR-01 system, patient positioning and port placement for robot-assisted ureteral reimplantation. a  The surgeon console. b  The patient cart. c  The vision cart. d  The patient was placed in Trendelenburg position, the patient cart was docked at the side of the operating table. Standard port placement included: one 12-mm camera port 2 cm superior to the umbilicus, two 9-mm robotic trocars 8 cm lateral to the umbilicus at its horizontal level, one 12-mm assistant port on the patient’s left side superior to the camera port, and one 5-mm assistant port on the patient’s left side superior to the iliac crest. For mid-distal ureteral lesions, all ports shifted cephalad proportionally. e  The three operating arms mounted on the beam can be rotated synchronously as a group to align with the patient’s position The schematic diagram of KD-SR-01 system, patient positioning and port placement for robot-assisted ureteral reimplantation. a  The surgeon console. b  The patient cart. c  The vision cart. d  The patient was placed in Trendelenburg position, the patient cart was docked at the side of the operating table. Standard port placement included: one 12-mm camera port 2 cm superior to the umbilicus, two 9-mm robotic trocars 8 cm lateral to the umbilicus at its horizontal level, one 12-mm assistant port on the patient’s left side superior to the camera port, and one 5-mm assistant port on the patient’s left side superior to the iliac crest. For mid-distal ureteral lesions, all ports shifted cephalad proportionally. e  The three operating arms mounted on the beam can be rotated synchronously as a group to align with the patient’s position After general anesthesia, the patient was placed in the 30° Trendelenburg position. The port placement is shown in Fig.  1 d. The patient cart was then docked at the patient’s side (Fig.  1 e), and the assistant sat on the same side of the robot. A pneumoperitoneum was established at 14 mmHg using a Veress needle, followed by placement of five abdominal trocars. After incision of the posterior peritoneum, the ureter was identified and carefully dissected at the level of the iliac vessels (Fig.  2 a). The ureter was transected above the diseased segment until urine could flow out smoothly. Approximately 4–5 cm of the healthy ureter was mobilized. Fat and scar tissue were removed from the ureter using cold scissors, while the periureteral blood supply was carefully preserved. In certain cases, indocyanine green (ICG) was used to visualize the ureter via the nephrostomy tube. Fig. 2 Surgical techniques and postoperative radiographic images of submucosal tunnel reimplantation. a  Dissection of ureter. b  Psoas hitch technique. c  Submucosal tunnel formation. The submucosal tunnel is outlined by yellow dashed lines. d Completed submucosal tunnel reimplantation ( e ) Postoperative three-dimensional reconstructed images of computed tomography urography. f  Postoperative cine magnetic resonance urography Surgical techniques and postoperative radiographic images of submucosal tunnel reimplantation. a  Dissection of ureter. b  Psoas hitch technique. c  Submucosal tunnel formation. The submucosal tunnel is outlined by yellow dashed lines. d Completed submucosal tunnel reimplantation ( e ) Postoperative three-dimensional reconstructed images of computed tomography urography. f  Postoperative cine magnetic resonance urography If the ureter was insufficient for a tension-free anastomosis, a psoas-hitch procedure was performed. Bladder hydrodistention of the bladder was firstly performed by filling 300 ml of normal saline through the indwelling Foley catheter. The bladder was then mobilized off from the anterior and both lateral pelvic walls. The bladder wall was fixed to the Psoas minor muscle tendon using 1 − 0 absorbable barbed sutures in a continuous manner. (Fig.  2 b). In this series, three distinct techniques of ureterovesical anastomosis were utilized: submucosal tunnel reimplantation, nipple reimplantation, and the Boari flap. The choice of technique was determined by the ureteral stump length and the ureteral dilation degree. Submucosal tunnel reimplantation is typically performed in patients with a relatively long ureteral stump and minimal or no significant luminal dilation. The nipple reimplantation technique may be considered when the ureteral stump demonstrates sufficient length and dilation to permit papillary formation. In cases where the ureteral stump is relatively short, making tension-free ureterovesical anastomosis technically challenging or unfeasible, the Boari flap is generally regarded as the preferred reconstructive approach. Submucosal tunnel reimplantation: A submucosal tunnel was created following the natural course of the ureter at the bladder dome. (Fig.  2 c). To ensure an anti-reflux effect, the ratio between the tunnel length and the ureteral diameter was maintained at 3:1. The ureter was connected to the bladder at the most distal part of the tunnel using a 4 − 0 Vicryl suture in an interrupted pattern. The submucosal tunnel was closed using a 4 − 0 Vicryl suture (Fig.  2 d). Nipple reimplantation: The ureter was folded back onto itself by about 1.5 cm to form an anti-reflux nipple using interrupted 4 − 0 sutures (Fig.  3 a). In cases of megaureter, intracorporeal tailoring of the dilated ureter was required, and the surgical technique was similar to what we previously described [ 18 ]. The redundant wall of the ureter was trimmed along its lateral aspect. The tailored ureter was then closed using 4 − 0 suture in a running manner, and an anti-reflux nipple was similarly formed in this scenario. Nipple ureteroneocystostomy was then performed at the lateral dome of the bladder using an interrupted 4 − 0 Vicryl suture (Fig.  3 b). Fig. 3 Surgical techniques and postoperative radiographic images of nipple reimplantation. a  Ureteral nipple formation. b  Completed nipple reimplantation. c  Postoperative three-dimensional reconstructed images of computed tomography urography. d Postoperative cine magnetic resonance urography Surgical techniques and postoperative radiographic images of nipple reimplantation. a  Ureteral nipple formation. b  Completed nipple reimplantation. c  Postoperative three-dimensional reconstructed images of computed tomography urography. d Postoperative cine magnetic resonance urography Boari flap: The surgical technique used was similar to what we previously described [ 19 ]. Specifically, a scaled stent was used to determine the distance from the proximal transverse section of the ureter to the fixed position of the psoas hitch. Subsequently, a bladder flap was created to be 1–2 cm longer than the defect requiring bridging, with the apex and base widths measuring approximately 1–2 cm and 3–4 cm, respectively. A side-by-side anastomosis was carried out between the apex of the flap and the spatulated ureter using 4 − 0 sutures (Fig.  4 a), and the bladder flap was tubularized by 3 − 0 barbed sutures in a continuous manner (Fig.  4 b). Fig. 4 Surgical techniques and postoperative radiographic images of Boari flap. a  The spatulated ureter is anastomosed to the tailored bladder flap. Short dashed lines outline the edges of the bladder flap; long dashed lines outline the suture lines for the ureterovesical anastomosis and the tubularization of the bladder flap. b  Completed Boari flap reimplantation. c  Postoperative three-dimensional reconstructed images of computed tomography urography. d Postoperative cine magnetic resonance urography Surgical techniques and postoperative radiographic images of Boari flap. a  The spatulated ureter is anastomosed to the tailored bladder flap. Short dashed lines outline the edges of the bladder flap; long dashed lines outline the suture lines for the ureterovesical anastomosis and the tubularization of the bladder flap. b  Completed Boari flap reimplantation. c  Postoperative three-dimensional reconstructed images of computed tomography urography. d Postoperative cine magnetic resonance urography Most patients remained hospital for 2–4 days until the drainage tube was removed. The urethral catheter was taken out 2 weeks after the surgery, and the ureteral stent was removed 2–3 months postoperatively. For patients with a nephrostomy tube, the tube was clamped 1–2 weeks postoperatively. Videourodynamic (VUD) assessment of the upper urinary tract was performed 1 week after ureteral stent removal. The nephrostomy tube was subsequently withdrawn upon VUD confirmation of unobstructed contrast drainage and absence of contrast extravasation. Follow-up consisted of clinical evaluation, serologic testing, and renal ultrasonography every 3 months after surgery. Functional cine magnetic resonance urography (cine MRU) was performed 3 months after surgery. Computed tomography urography was performed 6 months after surgery. Preoperative assessment, perioperative data and follow-up outcomes were prospectively collected. Preoperative data include demographics, clinical symptoms, serum creatinine (sCr), estimated glomerular filtration rate (eGFR), renal ultrasonography, CTU, and diuretic renal scan. Anterograde or retrograde urography was necessary for patients with ureteral stricture, while excretory cystourethrography was needed for patients with vesicoureteral reflux. Intraoperative data include docking time, operating time, and estimated blood loss (EBL). The docking time was defined as the interval from robotic cart initiation toward the operating table until final cannula-to-arm docking completion. Postoperative data included postoperative hospital stay (PHS), duration of catheterization, and postoperative complications. Follow-up included clinical symptoms, sCr, eGFR, imaging examinations and complications. Subjective success is defined as no tubes or stents in the body, no clinical symptoms, and no evidence of obstruction on imaging examinations. Complications were classified based on the Clavien-Dindo system. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) was utilized for the subjective assessment of ergonomics [ 20 ]. The NASA-TLX consists of six sub-facets addressing mental, physical, and temporal demands, perceived performance, effort, and frustration felt. We adapted the original NASA-TLX continuous rating scale (0-100) to a 10-point scale, omitting the weighting process and simply summing the ratings to generate an estimate of the overall workload [ 17 , 21 ]. As a prospective pilot study primarily assessing technically feasibility and safety, a formal sample size calculation was not performed. The sample size was determined in accordance with the IDEAL framework for early-phase surgical innovation studies and corresponds to established cohort sizes in robotic surgery feasibility trials [ 22 , 23 ]. Statistical analyses were performed using SPSS Statistics version 19.0 (IBM Corporation, Armonk, NY, USA). Measurement data are expressed as the median (interquartile range, IQR). Enumeration data are expressed as numbers (percentage). The 95% confidence interval (CI) was calculated using the binomial exact method. Categorical variables between groups were compared using Fisher’s exact test. Continuous variables between groups were compared using Student t test or Mann-Whitney U test.

In this study, 32 patients meeting the inclusion criteria were enrolled. 31 patients (96.9%) completed the treatment with ureteral reimplantation using KD-SR-01 system, while one patient (3.1%) was excluded because of transfer to ureteroureteral anastomosis using KD-SR-01 system. As shown in Table  1 , there was 5 men (16.1%) and 26 women (83.9%). The median age was 45 years (IQR, 35–51 years) and the body mass index was 23.8 kg/m 2 (IQR, 21.3–26.0 kg/m 2 ). Twenty patients presented with involvement of the left ureter, while 11 patients had involvement of the right ureter. Twenty-six patients (83.9%) presented with distal ureteral stricture, 3 (9.7%) presented with vesicoureteral reflux and 2 (6.5%) presented with ureterovaginal fistula. The median length of the ureteral strictures was 7 cm (IQR, 5–9.5 cm), and the median degree of vesicoureteral reflux was IV (IQR, III-IV). Table 1 Baseline characteristics of the patients Parameter Value Patients, n (%) 31 (100) Age (year), median (IQR) 45 (35–51) Gender, n (%) Male 5 (16.1) Female 26 (83.9) BMI (kg/m 2 ), median (IQR) 23.8 (21.3–26.0) Affected side, n (%) Left 20 (64.5) Right 11 (35.5) Diagnosis, n (%) Distal US 26 (83.9) VUR 3 (9.7) UVF 2 (6.5) Etiology, n (%) Ureteral endometriosis 8 (25.8) Ureteroscopic laser lithotripsy 6 (19.4) Gynecological surgery 4 (12.9) Pelvic radiation 2 (6.5) Obstructive megaureter 3 (9.7) Appendicitis 1 (3.2) Hematopoietic stem cell transplantation 1 (3.2) VUR after ureteral reimplantation 2 (6.5) Idiopathic 4 (12.9) Previous ureteral reconstruction surgery, n (%) 7 (22.6) Symptoms, n (%) Flank pain 9 (29.0) Hyperpyrexia 5 (16.1) Bladder irritation 4 (12.9) Vaginal discharge 2 (6.5) Asymptomatic 14 (45.2) Preoperative sCr (µmol/L), median (IQR) 69.3 (63.9–82.9) Preoperative eGFR (ml/min/1.73m 2 ), median (IQR) 91.0 (80.7–102.0) GFR of affected side (ml/min), median (IQR) 36 (24–43) Length of the US (cm), median (IQR) 7 (5-9.5) Degree for VUR, median (IQR) IV (III-IV) Preoperative placement of ureteral stent, n (%) DJ 7 (22.6) PCN 16 (51.6) IQR interquartile range, BMI body mass index, US ureteral stricture, VUR vesicoureteral reflux, UVF Ureterovaginal fistula, sCr serum creatinine, eGFR estimated glomerular filtration rate, GFR glomerular filtration rate, DJ double-J ureteral stent, PCN  percutaneous nephrostomy Baseline characteristics of the patients IQR interquartile range, BMI body mass index, US ureteral stricture, VUR vesicoureteral reflux, UVF Ureterovaginal fistula, sCr serum creatinine, eGFR estimated glomerular filtration rate, GFR glomerular filtration rate, DJ double-J ureteral stent, PCN  percutaneous nephrostomy As shown in Table  2 , the procedures were successfully completed without perioperative complications or conversion. Of the 31 cases, submucosal tunnel reimplantation was adopted in 11 patients (35.5%), nipple reimplantation was used in 10 patients (32.3%), while Boari flap was performed in 10 patients (32.3%). Psoas hitch was required in 26 patients (83.9%). In two patients (6.5%), ureteral reimplantation was performed in combination with bilateral ovarian cystectomy. In one patient (3.2%), unilateral ovariectomy was carried out. In one patient (3.2%), adrenalectomy was performed during the same procedure. The median operative time was 153 min (IQR, 136–178.5 min). The median EBL was 20 mL (IQR, 15–30 mL). The PHS was 4 days (IQR, 4–4 days). Table 2 Surgical outcomes and follow-up results Parameter Value Technique, n (%) Submucosal tunnel reimplantation 11 (35.5) Nipple reimplantation 10 (32.3) Boari flap 10 (32.3) Psoas hitch 26 (83.9) Combination of surgery, n (%) Unilateral ovariectomy 2 (6.5) Bilateral ovarian cystectomy 1 (3.2) Adrenalectomy 1 (3.2) Surgical conversion, n (%; 95% CI) 0 (0; 0-9.23) Docking time (min), median (IQR) 4.3 (3.2–5.2) Operative time (min), median (IQR) 153 (136-178.5) EBL (mL), median (IQR) 20 (15–30) Intraoperative complications, n (%; 95% CI) 0 (0; 0-9.23) PHS (day), median (IQR) 4 (4–4) sCr at discharge (µmol/L), median (IQR) 64.8 (57-74.9) eGFR at discharge (ml/min/1.73m 2 ), median (IQR) 103.0 (86.5-110.6) Follow up period (month), median (IQR) 22 (13–35) Symptom resolution, n (%; 95% CI) Over all 30 (96.8; 83.3–99.9) Submucosal tunnel reimplantation 10 (90.9; 58.7–99.8) Nipple reimplantation 10 (100; 69.1–100) Boari flap 10 (100; 69.1–100) Obstruction resolution, n (%; 95% CI) Over all 30 (96.8; 83.3–99.9) Submucosal tunnel reimplantation 10 (90.9; 58.7–99.8) Nipple reimplantation 10 (100; 69.1–100) Boari flap 10 (100; 69.1–100) Complications (CD classification), n (%; 95% CI) Grade I-II Over all 8 (25.8; 11.9–44.6) Submucosal tunnel reimplantation 2 (18.2; 2.3–51.8) Nipple reimplantation 3 (30.0; 6.7–65.2) Boari flap 3 (30.0; 6.7–65.2) Grade III-IV Over all   0 (0; 0-9.23) VUR-related syndromes, n (%; 95% CI) Over all 1 (3.2; 0.1–16.7) Submucosal tunnel reimplantation 0 (0; 0-28.5) Nipple reimplantation 1 (10; 0.3–44.5) Boari flap 0 (0; 0-30.9) Subjective success, n (%; 95% CI) Over all 30 (96.8; 83.3–99.9) Submucosal tunnel reimplantation 10 (90.9; 58.7–99.8) Nipple reimplantation 10 (100; 69.1–100) Boari flap 10 (100; 69.1–100) CI confidence interval, min minutes, IQR interquartile range, EBL estimated blood loss, PHS postoperative hospital stays, sCr serum creatinine, eGFR estimated glomerular filtration rate, GFR glomerular filtration rate, CD Clavien-Dindo, VUR  vesicoureteral reflux Surgical outcomes and follow-up results CI confidence interval, min minutes, IQR interquartile range, EBL estimated blood loss, PHS postoperative hospital stays, sCr serum creatinine, eGFR estimated glomerular filtration rate, GFR glomerular filtration rate, CD Clavien-Dindo, VUR  vesicoureteral reflux All patients completed the standardized follow-up assessments at 3 and 6 months postoperatively, with extended annual follow-up thereafter. Therefore, the follow-up duration varied based on recruitment time. The distribution of follow-up durations is presented in supplementary materials (see Supplementary Tables 1 and Supplementary Fig. 1). Then the patients were stratified into two groups based on follow-up duration: ≤18 months and > 18 months. Fisher’s exact test revealed no statistically significant difference in failure rates between the two groups ( p  = 1.00). At a median follow-up of 22 months (IQR, 13–35 months), 31 patients (96.8%) demonstrated improvement or resolution of both symptoms and hydronephrosis. CTU revealed no evidence of ureteral obstruction (Figs.  2 e, 3 c and 4 c), and cine magnetic resonance urography showed normal peristalsis and urine jets in the ureter (Figs.  2 f, 3 d and 4 d). The subjective success rate was 96.8% (30/31), with a 95% CI of 83.3–99.9%. The single failure case reported right flank discomfort following ureteral stent removal, with no significant improvement in hydronephrosis observed. This patient received reinsertion of DJ stent and continued to be followed up. Notably, one patient developed contralateral ureteral stricture, and underwent bilateral ileal ureter replacement 8 months after the initial surgery, precluding further protocol-specified follow-up. The initial procedure was still classified as successful based on follow-up results and the patent ureter confirmed during reoperation. No severe complications (Clavien-Dindo III or IV) occured in the patients. Eight patients (25.8%) developed postoperative urinary tract infection (Clavien-Dindo II), which were ameliorated with antibiotic therapy. One patient (3.2%) experienced VUR-related symptoms postoperatively. During the procedures, the KD-SR-01 system demonstrated several notable technical features. The suspended manipulator arm system allowed for rapid docking, with a median docking time of 4.3 min (IQR, 3.2–5.2 min). The instrument arm enabled dexterous manipulation during precise dissection and suturing. The 3D screen provided the surgeon with greater depth perception than the da Vinci robotic system, partially making up for the lack of haptic feedback. However, compared to optical lenses, this electronical lens was more prone to be contaminated and required intermittent cleaning. The surgeon reported a high level of comfort with the open console design due to significantly reduced neck strain and eye fatigue. The global, sub-item scores of the NASA-TLX were shown in Table  3 . Table 3 NASA-TLX score Mean ± SD NASA-TLX 9.47 ± 4.97 Mental demand 1.94 ± 1.58 Physical demand 1.82 ± 1.32 Temporal demand 2.05 ± 1.13 Performance 0.90 ± 0.51 Effort 1.65 ± 0.90 Frustration 1.11 ± 0.52 NASA-TLX National Aeronautics and Space Administration Task Load Index, SD  standard deviation NASA-TLX score NASA-TLX National Aeronautics and Space Administration Task Load Index, SD  standard deviation

Ureteral reimplantation is a critical aspect of distal ureteral reconstruction. After Ehlrich et al. introduced the first laparoscopic ureteral reimplantation in 1994 [ 1 ], minimally invasive surgery has become widely accepted for such procedures [ 2 ]. Compared with conventional open surgery, laparoscopic ureteral reimplantation demonstrates similar success rates while providing substantial benefits, such as decreased blood loss, reduced postoperative pain, shorter hospitalization durations, and accelerated recovery [ 3 , 4 ]. However, adoption of laparoscopic techniques has been limited by several challenges, including a long learning curve, technically demanding intracorporeal free-hand suturing, and relatively poor ergonomics for surgeons [ 5 , 6 ]. Since its approval for clinical use in 2000, the da Vinci ® robotic system (Intuitive Surgical, Inc., Sunnyvale, California) has revolutionized reconstructive urological surgery [ 7 , 8 ]. This system enhances surgical precision by providing superior three-dimensional (3D) visualization and enabling seven degrees of freedom in instrument manipulation. In addition, patients appeared to be more willing to accept robotic surgery, as they perceived it to be more effective and less invasive [ 9 ]. However, this system is associated with higher costs compared to open or laparoscopic approaches [ 10 ]. Over the last two decades, several surgical robot systems have emerged, including the HUGO™ RAS system, the Senhance™ system and Revo-i robot system, amongst others [ 11 – 13 ]. These new surgical robotic systems have emerged as potential alternatives, offering distinct technical features including modular design, an open control console, and telesurgery capabilities [ 14 ]. In China, the newly developed KD-SR-01 system (Suzhou Kangduo Robot Co., Ltd.) has demonstrated promising outcomes in partial nephrectomy, pyeloplasty, and radical prostatectomy [ 15 – 17 ]. This pilot study aims to assess the technical feasibility and safety of the KD-SR-01 system in robot-assisted ureteral reimplantation, as well as to evaluate preliminary efficacy outcomes and ergonomics.

Over the past two decades, there has been a rapid adoption of robot-assisted laparoscopic surgery in ureteral reconstruction. This transformation is largely driven by the advantages of robotic surgery in performing precise resections and accurate suturing. In this study, ureteral reimplantation was employed to evaluate the capability of KD-SR-01 system in lower ureteral reconstruction. All procedures were successfully completed. The techniques used included submucosal tunnel reimplantation, nipple reimplantation and Boari-flap. Additionally, some cases involved a combination with ovarian surgeries. The excluded patient underwent ureteroureteral anastomosis because of the relatively short stricture discovered during the surgery. Notably, no conversion to open or laparoscopic surgery was needed, demonstrating the practicability of the KD-SR-01 system. Perioperative parameters, including EBL and PHS, remained within acceptable limits. No severe perioperative complications were observed, which confirmed the safety of KD-SR-01 system. The subjective success rate of 96.8% was comparable to that reported in studies utilizing the da Vinci system, thereby demonstrating its preliminary efficacy (Supplementary Table 2) [ 24 – 32 ]. In terms of ergonomics, surgeons reported a high degree of comfort while using the KD-SR-01 system. Neck stiffness is a common issue in robotic surgeries using the da Vinci system, likely due to maintaining a static neck position for extended periods [ 33 ]. The open console design of this new robot system enables surgeons to keep their necks upright and adjust as needed, which reduces fatigue. Additionally, this design facilitates more effective communication between the surgeon and the assistant. Surgeons also noted reduced eye strain during operations, potentially attributable to the magnification and high-definition screen. However, further studies are required to objectively measure ocular strain [ 34 ]. In this study, we utilized the NASA-TLX to evaluate subjective workload. The overall NASA-TLX score was 9.47 ± 4.97, which is notably lower than the scores reported for laparoscopic procedures [ 35 ]. This finding suggests that this robotic system offers favorable ergonomic benefits. It is important to note, however, that the participating surgeon was highly experienced in robotic ureteral reconstruction, which may have introduced a selection bias into the subjective assessment of workload. Future research should incorporate more objective measures to evaluate fatigue and further validate these findings [ 5 ]. The KD-SR-01 system possesses several key features that enhance its functionality and versatility in robotic-assisted surgeries. First, the suspended manipulator arm system provides an extensive range of motion for multi-quadrant access. This design allows all arms to rotate synchronously to align with the patient’s position. This design not only simplifies the docking process but also minimizes the time required for docking. Second, the KD-SR-01 system can be integrated with commercially available 3D laparoscopic systems. This compatibility not only provides high-quality visualization but also reduces costs associated with specialized equipment. In ureteral reconstruction surgeries, the 3D high-definition visualization enables clear identification of the ureter, bladder, and surrounding tissues, facilitating meticulous manipulation during the procedure. This is especially crucial in redo cases, where anatomical landmarks may be less clearly defined. Third, the surgeon console features a dual-screen setup. The main screen displays real-time 3D high-definition images, providing surgeons with detailed intraoperative views. The secondary screen presents auxiliary images, offering additional guidance during the operation. Common auxiliary images include preoperative 3D image reconstructions [ 36 ], intraoperative ultrasound images, and real-time indocyanine green (ICG) imaging [ 37 ]. In this trial, ICG imaging was utilized for ureteral identification and precise definition of ureteral stricture margins, ensuring safer dissection and improved surgical outcomes (Fig.  5 ). Fig. 5 Realtime ICG imaging in ureteral reimplantation using the KD-SR-01 system. a  ICG imaging was displayed on the second screen. b  Identification of the ureter via near-infrared fluorescence imaging (NIRF), demonstrating characteristic yellow coloration. c Dissected ureter under NIRF. d Ureteral identification under white light vision. e Dissected ureter under white light vision Realtime ICG imaging in ureteral reimplantation using the KD-SR-01 system. a  ICG imaging was displayed on the second screen. b  Identification of the ureter via near-infrared fluorescence imaging (NIRF), demonstrating characteristic yellow coloration. c Dissected ureter under NIRF. d Ureteral identification under white light vision. e Dissected ureter under white light vision Despite its advantages, the KD-SR-01 system still has a few areas that could be improved. First, the system is equipped with only three arms: two instrument arms and one camera arm. Compared to the four-arm da Vinci system, a higher level of surgeon-assistant cooperation is required in complex ureteral reconstruction surgeries. Second, the stereoscopic vision of the KD-SR-01 system does not feature a naked-eye 3D display. Polarized glasses are required to view the 3D images on the main screen, and some surgeons reported discomfort when wearing these glasses for extended periods. Future advancements in visual ergonomics are anticipated, such as glasses-free 3D imaging, eye-tracking camera control, and integration of haptic feedback systems [ 38 – 40 ]. These new techniques could further enhance the surgical experience. This study has several limitations, such as the lack of a control group, the single center design, a relatively limited sample size, and short follow-up periods. The single-arm design does not allow for intergroup comparisons, and therefore primarily reflects technically feasibility and preliminary safety, rather than therapeutic efficacy. This study was conducted at a single tertiary center with all procedures performed by one surgeon with high surgical expertise. The single-center, single-surgeon design may introduce selection bias and limit the generalizability of the findings. The absence of a priori sample size calculation limits the statistical power to detect clinically relevant differences. The heterogeneity in indications and surgical techniques further reduced subgroup-specific statistical power. In addition, the absence of cost-effectiveness and learning curve analysis precludes direct comparison with other robotic systems [ 41 , 42 ]. Future larger-scale disease-specific randomized controlled studies with long follow-up will should examine therapeutic efficacy, quality of life assessment, cost-effectiveness analysis, and comparisons of robot performance and learning curves between different robotic systems [ 14 , 43 ].

Robotic-assisted ureteral reimplantation using the KD-SR-01 is technically feasible and safe. Further large-scale randomized controlled trials with extended follow-up periods are needed to validate its therapeutic efficacy.

Supplementary Material 1. Supplementary Material 1. Supplementary Material 2. Supplementary Material 2. Supplementary Material 3. Supplementary Material 3.