Mapping the global landscape of robot-assisted upper urinary tract reconstruction: a comprehensive bibliometric analysis

Introduction

Background

The surgical management of upper urinary tract strictures has undergone a revolutionary paradigm shift over the past two decades (1,2). Historically, open surgery represented the gold standard for complex upper urinary tract reconstruction; however, the emergence of the Da Vinci robotic surgical system has fundamentally transformed this clinical landscape (3,4). By providing three-dimensional magnified visualization, tremor filtration, and wristed instrumentation with seven degrees of freedom, robotic surgery effectively mitigates the technical constraints inherent in conventional laparoscopy, particularly within the challenging confines of deep pelvic or narrow retroperitoneal spaces (3,5). Consequently, the indications for robotic application have expanded rapidly—progressing from simple pyeloplasty to encompass complex procedures such as buccal mucosa graft (BMG) ureteroplasty, kidney auto-transplantation, and totally intracorporeal ileal ureter replacement (6-8).

Rationale and knowledge gap

Despite the increasing clinical literature describing these advances, the field lacks a macroscopic visualization of its underlying knowledge structure (9). Although individual high-volume centers have reported favorable technical outcomes (8,10), the absence of a comprehensive bibliometric synthesis leaves the urological community without a clear overview of the academic trajectory, collaboration patterns, and inter-institutional relationships that shape research in this specialized field.

Objective

To bridge this knowledge gap, this study aims to conduct a comprehensive bibliometric analysis of the literature concerning robot-assisted upper urinary tract reconstruction. By systematically mapping publication trends, geographical contributions, institutional networks, and evolving research hotspots, this study seeks to provide urologists and researchers with an overview of the field and to identify areas where future collaborative research is particularly needed. Clinically, these areas include the heterogeneity of stricture etiology, lesion location and length, prior interventions, renal functional assessment, definitions of success, and long-term follow-up after individualized reconstructive procedures. We present this article in accordance with the BIBLIO reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0314/rc).

Methods

A bibliometric study was performed using the Web of Science Core Collection (WoSCC) as the primary database. The updated search was conducted in the Topic field and covered the period from January 1, 1991 to June 20, 2026. The search strategy was: TS=((pyeloplasty OR ureteroplasty OR ureteroureterostomy OR ureteral reimplantation OR ureteroneocystostomy OR Boari flap OR psoas hitch OR ileal ureter OR ileal ureter replacement OR buccal mucosa graft OR oral mucosal graft OR lingual mucosal graft OR mucosal graft ureteroplasty OR appendiceal ureteroplasty OR upper urinary tract reconstruction OR ureteral reconstruction OR renal pelvis reconstruction) AND (robot OR robot-assisted OR robotic-assisted OR robotic surgery OR robotic surgical procedures OR da Vinci)).

The initial search identified 2,056 records. Only publications classified as articles or reviews were retained, and 725 records such as conference abstracts, editorial materials, early access items, letters, conference papers, corrigenda, news items, book chapters, withdrawn publications, and reprints were excluded. After this step, 1,331 publications remained. Forty-two non-English publications were further excluded, leaving 1,289 records. Upper urinary tract reconstruction was defined as robotic reconstructive procedures involving the ureter and ureteropelvic junction. 185 irrelevant studies, which primarily focused on bladder, urethral, vesicovaginal fistula, or other lower urinary tract reconstructive procedures were excluded, yielding 1,104 publications for the final bibliometric analysis (Figure 1A).

Figure 1 Flow diagram, publication trends, and global collaboration. (A) Literature identification, screening, and final inclusion. (B) Annual and cumulative publications from 2005 to 2025, demonstrating sustained and accelerating growth of research activity, particularly after 2020. (C) Top-10 most relevant countries. (D) Country collaboration network. MCP, multiple-country publications; SCP, single-country publications; WoSCC, Web of Science Core Collection.

Statistical analysis

Bibliographic data were exported in plain text format and analyzed using R software (v4.2.1) and the bibliometrix package. Descriptive analyses were performed to quantify annual publication growth, country output, author productivity, institutional productivity, journal distribution, and citation patterns. Bradford’s Law was used to identify core source journals. Country and author collaboration networks were constructed based on affiliation and co-authorship relationships. Keyword co-occurrence, topic trend, and burst analyses were performed after synonym merging to identify major research themes and emerging hotspots. No inferential hypothesis testing was performed, as this study was designed as a descriptive bibliometric analysis.

Results

Publication trends

The earliest publication on robotic upper urinary tract reconstruction was Sung et al.’s study [1999] (11). Annual output increased from 12 publications in 2005 to 116 publications in 2025, with a clear acceleration after 2020. Publications from 2020 to 2025 accounted for 501 records, nearly half of the 2005–2025 dataset. The highest annual output occurred in 2025, indicating continued growth of research activity in robot-assisted upper urinary tract reconstruction (Figure 1B).

Global contributions

A geographical analysis demonstrated the dominant contribution of the United States, which led the field with 539 publications, followed by China [137] and Italy [107] (Figure 1C). Although China ranked second in publication output, most studies were conducted through domestic collaborations [multiple-country publications (MCP) =8], reflecting the growing maturity and self-sufficiency of high-volume Chinese centers in robotic upper urinary tract reconstruction. The collaboration network identified the United States as the central hub of international cooperation, maintaining strong links with major European countries, particularly Italy, Germany, France, and the United Kingdom (Figure 1D). In contrast, European countries exhibited a higher degree of international collaboration relative to their publication volume, highlighting their important role in advancing global research partnerships.

Author analysis and institutional networks

Author analysis showed a concentrated but expanding research community. The five most productive authors were Gundeti MS (38 publications), Li XS (34 publications), Yang KL (34 publications), Li ZH (29 publications), and Eun DD (25 publications). Citation analysis among these productive authors showed high citation influence for Gundeti MS (889 citations) and Eun DD (801 citations), reflecting the impact of high-volume reconstructive and pediatric robotic surgery groups (Figure 2A).

Figure 2 Author analysis, institutional networks, and Bradford’s Law. (A) Top five productive authors. (B) Top-10 productive institutions. (C) Author collaboration network. (D) Cumulative publications of the top three productive institutions from 2010 to 2025. (E) Bradford’s Law core sources. (F) Top-10 most relevant journals.

Institutional analyses identified the University of Chicago as the most productive institution (44 publications), followed by New York University (35 publications), Peking University (35 publications), Children’s Hospital of Philadelphia (33 publications) and Cleveland Clinic (30 publications) (Figure 2B). Author collaboration analysis identified four major research clusters centered on leading institutions (Figure 2C). The largest and most densely connected cluster was led by Peking University (Li XS, Yang KL, Li ZH, and colleagues), while additional influential clusters were centered on New York University and Temple University (Eun DD, Zhao LC, Stifelman MD), the University of Chicago (Gundeti MS, Koh CJ, Noh PH), and a European pediatric urology network represented by Masieri L, Esposito C, and Escolino M. Overall, the field is driven by a small number of highly productive institutional teams with strong intra-group collaboration but relatively limited interaction between major clusters. Cumulative output curves from 2010 to 2025 showed that the University of Chicago, New York University, and Peking University represented the three leading institutional contributors (Figure 2D).

Journal analysis

Publication sources were widely distributed; however, Bradford’s Law identified four core journals: Journal of Endourology, Journal of Pediatric Urology, Urology, and Journal of Robotic Surgery. Among them, Journal of Endourology was the most productive source (116 publications), followed by Journal of Pediatric Urology (101 publications), Urology (86 publications), and Journal of Robotic Surgery (56 publications) (Figure 2E). The remaining top journals included The Journal of Urology, Journal of Laparoendoscopic & Advanced Surgical Techniques, World Journal of Urology, BJU International, Frontiers in Pediatrics, and Current Urology Reports. These findings indicate that research in robotic upper urinary tract reconstruction is concentrated within a small number of specialized urology journals, consistent with Bradford’s Law (Figure 2F).

Highly cited seminal papers

The ten most frequently cited papers are listed in Table 1. The most cited article was Lee et al. [2006], which compared pediatric robot-assisted laparoscopic dismembered pyeloplasty with open surgery and received 257 citations. This was followed by Autorino et al. [2014], a systematic review and meta-analysis of robot-assisted and laparoscopic repair of ureteropelvic junction obstruction, with 194 citations. Highly cited papers were predominantly focused on robotic pyeloplasty, ureteropelvic junction obstruction, ureteral reimplantation, and early fluorescence-guided ureteral reconstruction.

Keyword co-occurrence and evolutionary research hotspots

Keyword analyses were performed after synonym merging to reduce fragmentation of procedure- and disease-related terms. A total of 478 distinct keywords were identified. The most frequent keywords were pyeloplasty (506 occurrences), robotic surgery (450 occurrences), surgery (382 occurrences), pediatric (348 occurrences), laparoscopy (342 occurrences), clinical experience (257 occurrences), outcomes (241 occurrences), ureteropelvic junction obstruction (237 occurrences), management (204 occurrences), and ureteral reimplantation (183 occurrences). The keyword co-occurrence network demonstrated that pyeloplasty, robotic surgery, laparoscopy, pediatric reconstruction, outcomes, and ureteral reimplantation constituted the central knowledge structure of the field (Figure 3A).

Figure 3 Keyword co-occurrence and evolutionary research hotspots. (A) Top frequent merged keywords. (B) Topic trend analysis from 2016 to 2025, showing the evolution of research interests from established robotic pyeloplasty toward increasingly complex ureteral reconstructive procedures. (C) Keyword co-occurrence network. (D) Keyword burst analysis from 2016 to 2025.

Topic trend analysis revealed a clear evolution of research interests over time (Figure 3B,3C). Early studies primarily focused on robotic pyeloplasty, pediatric applications, and surgical feasibility, whereas more recent research has shifted toward procedure-specific and technically demanding reconstructive topics, including ureteral stricture, ureteral reconstruction, BMG, ureteroplasty, single-port surgery, and megaureter. This transition reflects the expansion of robotic surgery from established reconstructive procedures to increasingly complex ureteral reconstruction.

Keyword burst analysis further identified emerging research frontiers from 2016 to 2025 (Figure 3D). The strongest burst keyword was ureteroplasty (strength =5.96; 2024–2025), followed by single port (5.10; 2023–2025), repair (4.15; 2020–2021), ureteral stricture (3.91; 2024–2025), and reconstructive urology (3.86; 2025). The recent emergence of terms related to ureteral reconstruction, graft-based techniques, and next-generation robotic platforms suggests that complex ureteral stricture management and advanced reconstructive procedures have become the predominant research focus in contemporary robotic urology.

Discussion

Key findings

This bibliometric analysis revealed several key findings. First, research on robotic upper urinary tract reconstruction has grown steadily, especially after 2020, reflecting wider global adoption of robotic technology. Second, research output is concentrated in a few countries and institutions, with the United States leading and China rapidly increasing its contributions. Third, the field is mainly based on robotic pyeloplasty, pediatric reconstruction, and ureteral reimplantation, which are the most influential topics. Finally, recent studies are shifting toward more complex procedures (22,23), such as ureteral stricture management, ureteroplasty, BMG reconstruction, and single-port robotic surgery, indicating ongoing advancements in techniques and technology.

Strengths and limitations

This study possesses several strengths: it offers a macroscopic visualization of the field’s knowledge structure, employs bibliometric tools to map global collaboration networks, and provides a long-term temporal analysis of research hotspots. However, limitations must be acknowledged. First, bibliometric data are affected by citation lag, meaning that recent clinically relevant studies may not yet have accumulated sufficient citations. Second, citation-based indicators may be influenced by self-citation and field-specific citation practices. Third, the reliance on WoSCC and English-language publications may exclude non-indexed regional literature and non-English studies, potentially overlooking localized innovations. Fourth, bibliometric metrics reflect publication frequency and citations rather than the intrinsic clinical quality, safety, durability, or patient-centered value of individual surgical techniques. Finally, because upper urinary tract reconstruction is highly individualized, bibliometric patterns should be interpreted as indicators of research activity rather than direct evidence for standardized treatment algorithms.

Comparison with similar research

Unlike previous studies that have focused exclusively on a certain procedure or general robotic urology, this analysis specifically isolates the niche of upper urinary tract reconstruction (24). While other bibliometric reviews have documented the rise of robotic surgery in urology, our findings emphasize a more pronounced shift toward “complex” reconstructions compared to earlier, broader studies. Furthermore, the identified collaboration patterns align with existing literature in robotic oncology, though our findings uniquely highlight the relative scarcity of inter-cluster cooperation specifically within the sub-specialty of reconstructive urology, distinguishing it from the highly collaborative nature of robotic prostatectomy research.

Explanations of findings

The increased publication activity observed after 2020 may correlate with broader adoption of robotic platforms, accumulated surgeon experience, and growing interest in complex reconstructive indications. The prominent contributions from the U.S. and China may reflect the maturation of high-volume urological centers in these countries and a shift from general robotic applications toward complex reconstructive challenges. The concentration of publications and citations within core journals and productive institutions, as predicted by Bradford’s Law, suggests that dissemination in specialized urology journals plays an important role in shaping academic attention in this field.

Implications and actions needed

This bibliometric analysis suggests that robotic upper urinary tract reconstruction is evolving from an exploratory technique into a more mature field. As surgical indications expand from pyeloplasty to more complex ureteral reconstruction, future studies should focus not only on feasibility but also on long-term outcomes, quality of life, cost-effectiveness, and patient-centered measures. Although publication output has increased rapidly, most studies are still single-center and retrospective, mainly from a few high-volume institutions and indications and technique selection remain poorly standardized. Collaboration is strong within individual groups but limited between international centers. Because upper urinary tract reconstruction is individualized according to etiology, stricture length and location, prior interventions, renal function, tissue availability, and patient comorbidity, future guidelines should focus on standardized reporting, definitions and decision frameworks (8,25). Therefore, multicenter registries, standardized reporting, and broader collaboration are needed to improve data quality and generalizability (26).

The rise of ureteroplasty, graft-based reconstruction, and single-port robotic surgery highlights the need for prospective comparative studies. High-quality evidence from multicenter prospective and randomized studies will be essential to guide clinical practice and improve outcomes (27).

Conclusions

This updated bibliometric analysis tracks the evolving literature on robot-assisted upper urinary tract reconstruction using 1,104 screened publications. Research output has increased steadily, particularly in recent years. The United States remains the leading contributor, while China is rapidly emerging as a key independent research force. Early studies focused on pyeloplasty and basic reconstruction, whereas recent work has shifted toward more complex ureteral procedures and new robotic techniques. Despite these advances, collaboration between major research groups remains limited. Future efforts should focus on multicenter cooperation, standardized outcomes, and higher-quality evidence to further improve patient care.

Acknowledgments

The authors would like to thank all of the medical staff who participated in this study.

Footnote

Reporting Checklist: The authors have completed the BIBLIO reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0314/rc

Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0314/prf

Funding: This study was supported by Capital’s Funds for Health Improvement and Research (No. 2024-1-4072).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0314/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.

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/.

References

1. Mufarrij PW, Shah OD, Berger AD, et al. Robotic reconstruction of the upper urinary tract. J Urol 2007;178:2002-5. [Crossref] [PubMed]
2. Kim S, Buckley JC. Robotic Lower Urinary Tract Reconstruction. Urol Clin North Am 2021;48:103-12. [Crossref] [PubMed]
3. Beale R, Sicilila S, Riestra P, et al. Are robots the future? A case for robotic pyeloplasty as the gold standard treatment in ureteropelvic junction obstruction. Curr Opin Urol 2022;32:109-15. [Crossref] [PubMed]
4. Grosso AA, Di Maida F, Paganelli D, et al. Complex Ureteral Reconstruction via Open or Robotic Ureteroplasty with a Buccal Mucosa Onlay Graft: A Two-center Comparison. Eur Urol Open Sci 2025;71:125-31. [Crossref] [PubMed]
5. Hebert KJ, Linder BJ, Gettman MT, et al. A Contemporary Analysis of Ureteral Reconstruction 30-Day Morbidity Utilizing the National Surgical Quality Improvement Program Database: Comparison of Minimally Invasive vs Open Approaches. J Endourol 2022;36:209-15. [Crossref] [PubMed]
6. Yee CH, Ko IC, Tam HM, et al. Robotic Bilateral Ileal Interposition: The Total Intracorporeal Approach. Int Braz J Urol 2025;51:e20250359. [Crossref] [PubMed]
7. Yang K, Fan S, Wang J, et al. Robotic-assisted Lingual Mucosal Graft Ureteroplasty for the Repair of Complex Ureteral Strictures: Technique Description and the Medium-term Outcome. Eur Urol 2022;81:533-40. [Crossref] [PubMed]
8. Yang K, Pang KH, Fan S, et al. Robotic ureteral reconstruction for benign ureteral strictures: a systematic review of surgical techniques, complications and outcomes : Robotic Ureteral Reconstruction for Ureteral Strictures. BMC Urol 2023;23:160. [Crossref] [PubMed]
9. Wang J, Fan M, Qiang Z, et al. Global research trends of robotic-assisted surgery in Urogynecology and Reconstructive Pelvic Surgery: a bibliometric and visualization analysis based on web of science. J Robot Surg 2025;19:671. [Crossref] [PubMed]
10. Lee M, Lee Z, Houston N, et al. Robotic ureteral reconstruction for recurrent strictures after prior failed management. BJUI Compass 2023;4:298-304. [Crossref] [PubMed]
11. Sung GT, Gill IS, Hsu TH. Robotic-assisted laparoscopic pyeloplasty: a pilot study. Urology 1999;53:1099-103. [Crossref] [PubMed]
12. Lee RS, Retik AB, Borer JG, et al. Pediatric robot assisted laparoscopic dismembered pyeloplasty: comparison with a cohort of open surgery. J Urol 2006;175:683-7; discussion 687. [Crossref] [PubMed]
13. Autorino R, Eden C, El-Ghoneimi A, et al. Robot-assisted and laparoscopic repair of ureteropelvic junction obstruction: a systematic review and meta-analysis. Eur Urol 2014;65:430-52. [Crossref] [PubMed]
14. Link RE, Bhayani SB, Kavoussi LR. A prospective comparison of robotic and laparoscopic pyeloplasty. Ann Surg 2006;243:486-91. [Crossref] [PubMed]
15. Lee Z, Moore B, Giusto L, et al. Use of indocyanine green during robot-assisted ureteral reconstructions. Eur Urol 2015;67:291-8. [Crossref] [PubMed]
16. Casale P, Patel RP, Kolon TF. Nerve sparing robotic extravesical ureteral reimplantation. J Urol 2008;179:1987-9; discussion 1990. [Crossref] [PubMed]
17. Mufarrij PW, Woods M, Shah OD, et al. Robotic dismembered pyeloplasty: a 6-year, multi-institutional experience. J Urol 2008;180:1391-6. [Crossref] [PubMed]
18. Braga LH, Pace K, DeMaria J, et al. Systematic review and meta-analysis of robotic-assisted versus conventional laparoscopic pyeloplasty for patients with ureteropelvic junction obstruction: effect on operative time, length of hospital stay, postoperative complications, and success rate. Eur Urol 2009;56:848-57. [Crossref] [PubMed]
19. Smith RP, Oliver JL, Peters CA. Pediatric robotic extravesical ureteral reimplantation: comparison with open surgery. J Urol 2011;185:1876-81. [Crossref] [PubMed]
20. Marchini GS, Hong YK, Minnillo BJ, et al. Robotic assisted laparoscopic ureteral reimplantation in children: case matched comparative study with open surgical approach. J Urol 2011;185:1870-5. [Crossref] [PubMed]
21. Yee DS, Shanberg AM, Duel BP, et al. Initial comparison of robotic-assisted laparoscopic versus open pyeloplasty in children. Urology 2006;67:599-602. [Crossref] [PubMed]
22. Cho EY, Chaudry AE, Puri D, et al. Outcomes of Robot-assisted Appendiceal Ureteroplasty From a Multi-institutional Experience. Urology 2024;192:136-40. [Crossref] [PubMed]
23. Bourillon A, McGuire BB, Pinar U, et al. Robot-assisted Buccal Mucosa Graft Ureteroplasty for Ureteral Stricture: A European Multicenter Case Series. Eur Urol Open Sci 2026;83:166-72. [Crossref] [PubMed]
24. Zhang Y, Yan R, Wang K, et al. Global trends in robot-assisted ureteral reimplantation: a bibliometric and visualization analysis. J Robot Surg 2026;20:488. [Crossref] [PubMed]
25. Saini S, Lukas V, Pathak RA, et al. Robot-Assisted Laparoscopic Ureteral Reconstruction for Malignant Pathology: Single-Center Experience with Analysis of Perioperative, Functional, and Oncologic Outcomes. J Endourol 2023;37:42-9. [Crossref] [PubMed]
26. Ji E, Naser-Tavakolian A, Kanabolo D, et al. Reconstruction of a Devastated Ureter: Multi-institutional Experience with Robotic Intracorporeal Ileal Ureter Replacement. Eur Urol 2026;89:541-9. [Crossref] [PubMed]
27. Prebay ZJ, Schneider A, Shah S, et al. Surgical success following robotic upper urinary tract reconstruction, results from a global network of healthcare organizations. J Robot Surg 2025;19:761. [Crossref] [PubMed]