A bibliometric study of the top 100 most-cited papers in ureteral stricture reconstruction

Abstract

Background

Ureteral stricture is caused by iatrogenic and non-iatrogenic factors. The treatment of ureteral stricture usually involves ureteral reconstruction. This study aimed to identify and analyze the top 100 most cited (T100) papers in ureteral stricture reconstruction, a field lacking prior bibliometric analysis.

Methods

Using the Web of Science Core Collection, we retrieved the T100 articles and review articles on ureteral stricture reconstruction and applied bibliometric tools (CiteSpace, VOSviewer, Bibliometrix) to examine citation patterns, authorship, geographic distribution, journal distribution, co-citation networks, and keyword trends.

Results

The T100 articles received 4 to 130 citations each, with an average of 25.13. Publications originated from 23 countries, with the USA leading (56 papers, 1,635 total citations) followed by China (17 papers). Temple University (USA, 12 papers) and Peking University (China, 9 papers) were among the most productive institutions. Daniel D. Eun was the top contributing author (12 papers). Urology, Journal of Endourology, and Journal of Urology were the most productive journals. Topic and keywords analysis shows the hot spots of mucosa grafts and robot-assisted surgery.

Conclusions

Our study provides a comprehensive overview of influential literature in ureteral stricture reconstruction. Ureteral stricture reconstruction is an emerging research field. Mucosa grafts and robot-assisted surgery are likely to be hot topics in the future.

Highlight box.

Key findings

• Mucosa grafts and robot-assisted surgery are likely to be hot topics in the future.

What is known and what is new?

• Ureteral stricture is caused by iatrogenic and non-iatrogenic factors.

• The most productive country is the USA, and the most productive institution is Temple University.

What is the implication, and what should change now?

• Robotic-assisted reconstruction and oral mucosa grafts are hot topics in ureteral reconstruction and should be further studied.

Introduction

Ureteral stricture refers to an abnormal narrowing of the ureteral lumen, which can result from various etiologies, including iatrogenic injury (e.g., post-surgical or endoscopic procedures), trauma (e.g., external injury or radiation), pathological conditions (e.g., malignancy, infections, or retroperitoneal fibrosis), or congenital anomalies (e.g., ureteropelvic junction obstruction) (1). The incidence of ureteral stricture is 1.5% in patients with stones and 3% in renal transplant patients (2,3). Untreated ureteral stricture may cause short-term and long-term complications, including functional obstruction and chronic renal failure (4). The treatment of ureteral stricture usually involves ureteral reconstruction to restore the patency of the ureter and ensure smooth drainage of the kidneys (5). With the rapid progress of technological advancements in urology, there have been significant changes in surgical treatment for urological diseases, including pure laparoscopic and robotic-assisted approaches to ureteral stricture (6-8). Advancements in operative laparoscopy, such as the integration of the da Vinci robotic surgical instruments, have allowed surgeons to explore a broader range of choices for reconstructing ureteral strictures (9).

Bibliometrics is a discipline that analyzes the citation relationships in scientific literature, and it measures the influence and recognition of an article or researcher in the scientific community through citation counts (10). In the medical field, especially in specialties such as urology, the number of citations is often considered a key indicator of the quality and importance of a study (11,12). Although many studies have endeavored to identify and assess the “citation classics” within specific domains, as of now, no bibliometric studies have been conducted in the field of ureteral stricture reconstruction.

This study aims to fill this gap by identifying and analyzing the top 100 most cited (T100) papers in the field of ureteral stricture reconstruction, to reveal the research trends and key contributors in this field. These highly cited papers not only represent significant advancements in the field but also may reveal potential directions for future research. Through an in-depth analysis of these highly cited papers, we aim to identify the most influential research topics in the field of urology, as well as the researchers, countries/regions, and institutions that have made significant contributions to the field.

Methods

Data source

On November 12, 2024, the Web of Science Core Collection (WOSCC) database was queried to retrieve relevant papers in the field of ureteral stricture repair and reconstruction. A complex search strategy in the form of title (TI), abstract (AB), and author keywords (AK) was used to enhance the accuracy of retrieval and ensure more targeted results aligned with the focus of our study (13). The specific query expression was: (TI=(ureteral stricture) AND TI=(reconstruction)) OR (AB=(ureteral stricture) AND AB=(reconstruction)) OR (AK=(ureteral stricture) AND AK=(reconstruction)). Papers related to ureteral stricture repair and reconstruction published between 2000 and 2024 were selected based on the number of citations. Our analysis included only articles and review articles published in English between January 1, 2000 and November 10, 2024. Publications in other languages or of different types—such as meeting abstracts, proceedings papers, editorials, letters, and early access items—were not included. All T100 papers were screened by an author and checked by two independent urologists to ensure accuracy and completeness. The following information of the papers was further analyzed: annual publication number, country/region, institution, journal, author, co-cited references, topic, and keywords.

Statistical analysis

In this study, various software tools were employed to conduct bibliometric analyses at different levels. CiteSpace (Chaomei Chen, Drexel University, Philadelphia, PA, USA) is a visualization software specially designed for illustrating trends and patterns in scientific literature. The software supports functions such as tracking co-citation relationships, detecting frequently co-occurring keywords, and pinpointing newly emerging research areas (14-16). In our research, it was applied to analyze the distribution of publications across countries and institutions, reference co-citation patterns, and keyword co-occurrence. The analysis was conducted using a one-year interval for each time slice to capture fine-grained changes in thematic evolution, especially considering the relatively recent and fast development of the field. The parameter g-index k =25 was set, following recommendations from developers and common practices in similar bibliometric studies. VOSviewer (Centre for Science and Technology Studies, Leiden University, Leiden, The Netherlands) is a software tool for constructing and visualizing bibliometric networks (17,18). Bibliometrix (Massimo Aria and Corrado Cuccurullo, University of Naples Federico II, Naples, Italy) is an open-source R package designed for comprehensive science mapping analysis (19). Microsoft Office Excel (Microsoft Corporation, Seattle, WA, USA) was used to plot the annual publication and citation graph. For country-level analysis, CiteSpace was utilized to construct collaborative networks, identifying the global research landscape and leading nations in the field. Author-level analysis and visualization and institutional collaboration networks were performed using VOSviewer to identify key researchers and institutions. Journal impact and distribution across research areas were assessed using the Bibliometrix R package. Cited reference analysis was conducted using CiteSpace to reveal the foundational studies and key references driving the field’s development. Finally, keyword co-occurrence analysis was carried out in CiteSpace to identify research trends and hotspots. All automated outputs from bibliometric tools were manually verified by two authors to ensure data accuracy.

Results

Summary bibliographic information

The T100 papers in the field of ureteral stricture reconstruction were searched and screened by two independent authors. Figure 1 illustrates the annual numbers of publications and citations. The citation counts for the T100 papers ranged from 4 to 130, with an average of 25.13. The most-cited paper authored by Armatys et al. in 2009, discussed the use of ileal segments for ureteral substitution in reconstructive urology (20). The latest T100 paper, published in 2023 with 10 citations, explored the application of robot-assisted laparoscopic ileal ureter reconstruction in the treatment of ureteral stricture (21).

Figure 1.

The year distribution of published literature. The figure illustrates the total cumulative citations received by articles published each year.

Country/region and institutional analysis

A total of 23 countries/regions contributed to the T100 papers, with 10 of them associated with equal or more than two papers, as detailed in Table 1. Figure 2A,2B show the country/region collaborative network between countries/regions, the thickness of the lines indicates the strength of international collaboration. The USA ranked first in the world in both the counts of publications and citations with 56 papers and 1,635 citations, followed by China (17 papers and 312 citations) and Germany (five papers and 123 citations). Among the 100 papers analyzed, only 9% involved international collaboration (Table S1).

Table 1. Countries of origin for the top 100 most cited papers.

Rank	Country	Number of publications	Citations	Average citations per article
1	USA	56	1,635	29.20
2	China	17	312	18.35
3	Germany	5	123	24.60
4	India	3	54	18.00
5	France	3	50	16.67
6	Belgium	3	46	15.33
7	Egypt	2	66	33.00
8	Spain	2	63	31.50
9	Canada	2	60	30.00
10	South Korea	2	51	25.50

Figure 2.

Country/region analysis. (A) The country/region collaborative network visualization. The node size represents the number of publications. (B) The world map of country/region collaboration. The depth of blue represents the number of publications, and the thickness of the red connecting line represents the intensity of cooperation between countries. The color grey indicates no publication in certain country/region.

A total of 123 institutions contributed to the T100 papers, with 12 of them participating in more than three papers, as outlined in Table 2. Among these top institutions, five are based in the USA, six in China, and one in Belgium. Temple University (12 papers and 389 citations), Peking University (nine papers and 156 citations), and Hackensack University Medical Center (seven papers and 173 citations) occupied the top three positions regarding number of published papers among all institutions analyzed. The institution with the greatest average citation per article was University of California San Francisco, with an average of 38.33 citations per article and three publications that ranked seventh.

Table 2. The most productive institutions in the top 100 most cited papers.

Rank	Institution	Number of publications	Citations	Average citations per article	Country
1	Temple University	12	389	32.42	USA
2	Peking University	9	156	17.33	China
3	Hackensack University Medical Center	7	173	24.71	USA
4	Emergency General Hospital	7	138	19.71	China
5	New York University	6	194	32.33	USA
6	National Urological Cancer Center	4	76	19.00	China
7	University of California San Francisco	3	115	38.33	USA
8	Wake Forest University	3	87	29.00	USA
9	Beijing Jiangong Hospital	3	61	20.33	China
10	Huazhong University of Science and Technology	3	61	20.33	China
11	Peking University First Hospital	3	48	16.00	China
12	Ghent University Hospital	3	46	15.33	Belgium

Journal distribution analysis

The T100 papers were published across 33 journals, comprising both general and primarily urology-focused journals. Among these, 14 journals published more than two T100 papers, as detailed in Table 3. Urology published the highest number of T100 papers and accounting for 345 citations. This was followed by the Journal of Endourology, with 16 T100 papers and 196 citations, and the Journal of Urology, which, despite publishing nine T100 papers, had the highest citation count at 612.

Table 3. Journal distribution of the top 100 most cited papers.

Rank	Journal	Number of publications	Citations	Average citations per article	2023 IF	2023 IF quantile	5-year’s IF
1	Urology	20	345	17.25	2.1	Q2	2.2
2	Journal of Endourology	16	196	12.25	2.9	Q1	3.4
3	Journal of Urology	9	612	68.00	6.4	Q1	6.1
4	European Urology	6	127	21.17	25.3	Q1	19.4
5	International Journal of Urology	5	26	5.20	1.8	Q3	2.4
6	International Urology and Nephrology	5	23	4.60	1.8	Q3	2.0
7	Current Opinion in Urology	4	17	4.25	2.1	Q2	2.2
8	Current Urology Reports	3	24	8.00	2.5	Q2	2.7
9	Transplantation Proceedings	3	19	6.33	0.8	Q4	0.8
10	Investigative and Clinical Urology	2	10	5.00	2.5	Q2	2.2
11	Journal of Laparoendoscopic & Advanced Surgical Techniques	2	17	8.50	1.1	Q3	2.0
12	Translational Andrology and Urology	2	7	3.50	1.9	Q3	2.3
13	Urologia Internationalis	2	22	11.00	1.5	Q3	1.5
14	Urologic Clinics of North America	2	36	18.00	2.4	Q2	2.4

IF, impact factor.

Authors analysis

A total of 458 researchers worldwide contributed to the T100 papers. Scientists who authored more than six T100 papers are shown in Table 4. An author collaboration network is rendered in Figure 3A, and details of the top five author clusters are illustrated in Figure S1. Daniel D. Eun from Temple University ranked the first, contributing 12 T100 papers (five as corresponding author) and 389 citations. Ziho Lee (who was trained under Dr. Eun) ranked second, contributing 10 T100 papers, including five as the first author and four as a second or co-author, with a total of 359 citations. Xuesong Li from Peking University First Hospital also authored 10 T100 papers, all as the corresponding author, garnering 165 citations. Figure 3B shows the changes in author activity over time, and it is evident that the top authors have been productive since 2015.

Table 4. The most productive authors in the top 100 most cited papers.

Rank	Author	Number of publications	First author	Second or third author	Corresponding author	Others	Current affiliation	Country	Citations
1	Eun, Daniel D.	12	0	0	5	7	Temple University	USA	389
2	Lee, Ziho	10	5	4	0	1	Northwestern Medicine	USA	359
3	Li, Xuesong	10	0	0	10	0	Peking University First Hospital	China	165
4	Stifelman, Michael D.	9	0	1	8	0	Hackensack University Medical Center	USA	245
5	Metro, Michael J.	8	0	0	0	8	Temple University	USA	211
6	Yang, Kunlin	8	3	1	0	4	Peking University First Hospital	China	126
7	Zhou, Liqun	8	0	0	3	5	Peking University First Hospital	China	107
8	Zhang, Peng	7	0	0	1	6	Emergency General Hospital	China	138
9	Li, Xinfei	7	1	3	0	3	Peking University First Hospital	China	101
10	Zhao, Lee C.	6	2	0	1	3	New York University, Langone Medical Center	USA	190
11	Xiong, Shengwei	6	1	2	0	3	Peking University First Hospital	China	130
12	Lee, Randall A.	6	0	4	0	2	Temple University	USA	109
13	Fan, Shubo	6	1	4	0	1	Peking University First Hospital	China	107
14	Li, Zhihua	6	0	1	0	5	Peking University First Hospital	China	87

Figure 3.

Author analysis. (A) Author collaborative network visualization. Each color represents a collaboration cluster, and each node represents an author. The node size represents the number of publications, and the thickness of connecting lines represents the intensity of cooperation between authors. (B) Author collaborative network visualization with time overlay. Each node represents an author. The node size represents the number of publications, and the thickness of connecting lines represents the intensity of cooperation between authors.

References co-citation analysis

A total of 392 references were included in the analysis. Figure 4A presents the co-citation network of referenced articles, where articles with citations greater than or equal to 6 times are tagged on the diagram. “Robotic Ureteral Reconstruction Using Buccal Mucosa Grafts: A Multi-institutional Experience” published by Lee C. Zhao had the highest co-citation count and highest co-citation burst, which reported the safety and effectiveness of robotic buccal mucosa ureteral reconstruction in the treatment of benign middle and proximal ureteral stricture (22). Figure 4B shows the clusters of co-cited references, including “buccal mucosa”, “endoscopic management”, and “ureteral stricture reconstruction”, all of which had silhouette values exceeding 0.8, suggesting that the clustering results were highly reliable.

Figure 4.

Co-cited references analysis. (A) Co-cited references network visualization. The color represents a reference publication year, the node size represents the number of publications, and the thickness of connecting lines represents the connection strength of references. (B) Clusters of co-cited references. Each color represents a specific cluster.

Topic and keywords analysis

After the summarizing of topics in the T100 papers, 37 articles predominantly address reconstructions associated with robotic assistance, nine articles focused on buccal mucosa reconstructions, six discussed ileum reconstructions, and five articles each discussed reconstructions related to the lingual mucosa and appendix. Additionally, two articles focus on small intestine mucosa reconstructions.

The keywords reflect the core and focus of a paper. A total of 225 keywords were included in our analysis, the complete keywords are shown in Table S2. Keywords network is illustrated in Figure 5A, and keywords with frequency of occurrence equal to or more than 11 were labeled, among which the five most frequently appearing keywords were “experience”, “replacement”, “management”, “robotic surgery” and “reimplantation”. Besides, “ileal ureter” ranked 8^th, “buccal mucosa graft” ranked 12^th, and “lingual mucosa graft” ranked 24^th. Centrality reflects how strongly a node is linked to others across the whole network; nodes exhibiting high centrality (indicating strong intermediary roles and substantial influence) were highlighted using magenta-colored circles. A total of 12 keywords exhibited centrality values of 0.1 or higher, the top five of them were “complications”, “experience”, “management”, “replacement”, and “buccal mucosa graft”. Figure 5B displays the 10 most prominent clusters, where the largest clusters were “robotic management”, and “mucosal graft ureteroplasty”, as well as “complex ureteral reconstruction”. As all silhouette scores were above 0.65, the clustering results could be considered reasonably sound.

Figure 5.

Keywords analysis. (A) Keywords network visualization. The color represents the year of a keyword, the node size represents the importance of keywords, and the thickness of connecting lines represents the connection strength of keywords. (B) The top 10 clusters of keywords. Each color represents a specific cluster.

Discussion

General information

With the continuous development of urology, more and more literature has focused on the development and prospects of ureter reconstruction techniques. However, there has been no bibliometric analysis addressing the status and trends in this field, so our study was conducted to evaluate it. A total of 458 researchers from across the globe contributed to the T100 papers, which were published in 33 different journals. The data suggest that ureter reconstruction has gradually become one of the emerging hot research areas in the field of urology.

Despite research in the field of ureter reconstruction being conducted worldwide, the highest citation rate and the largest number of publications were both from the USA. The significant influence of the USA may be attributed to the talented and innovative surgeons in this country and substantial research funding. Collaborative groups, notably Collaborative of Reconstructive Robotic Ureteral Surgery, significantly influenced multi-institutional studies on ureteral reconstruction (23-25). Additionally, China also plays an important role in ureter research. This also indicates the urgent importance of increased international participation and collaborative efforts in research from other nations, especially from developing countries. The country/region analysis also showed few international collaborations, so interdisciplinary exchanges and cooperation such as academic conferences or online surgical demonstration should be promoted, especially international cooperation.

Identification of hotspots

Numerous urologists have carried out diverse attempts and made remarkable contributions to the material of ureteral stricture reconstruction. The top-cited paper by Armatys et al., describes the utilization of ileum segments for ureteral replacement in reconstructive urology (20). The latest paper discussed the application of intracorporeal robot-assisted ileal ureter substitution in the surgical treatment of ureteric strictures (21). Since this technique was first reported in 2003, it is evident that the ileal ureteric replacement is a traditional approach and it remains an important approach in the field of ureter reconstruction, with multiple studies still focusing on this aspect (26-28). Ureteroplasty using an appendix graft, first reported in 2009, allows a tension-free, watertight anastomosis while maintaining the vascular supply to the appendix, with a much lower risk of electrolyte abnormalities compared with ileal ureter reconstruction (29,30). Some articles focus on reconstruction using oral mucosa grafts. Buccal mucosa transplantation ureteroplasty is a specialized approach employed to treat ureteral strictures longer than 3 cm which are irreparable via end-to-end anastomosis (27). Not only does the buccal mucosa share similar characteristics with the inner lining of urinary tracts but it is also easily accessible (31-33). This technique mitigates damage to the delicate blood supply of the ureter and facilitates the establishment of a seamless connection with minimum stress (34). Some centers have reported buccal mucosa graft ureteroplasty, showing feasibility and safety (22,24,34,35). A study in 2022 compared the robot-assisted buccal mucosa graft ureteroplasty with endoscopic stenting for the first time, verified its superiority in resolution of hydronephrosis, glomerular filtration rate, as well as physical and psychological quality of life compared with endoscopic stent placement (36). Notably, in 2016, Li et al. have proposed for the first time internationally a novel laparoscopic onlay lingual mucosa graft ureteroplasty for proximal ureteral stricture for patients with ureteral strictures at the proximal end, and the new technique has set a precedent for patients with proximal ureteral stricture and seems to be an excellent choice for the treatment method, especially under the condition of buccal mucosa deficiency caused by betel nut consumption (37). Two reports in 2022 shared the experience with robot-assisted and laparoscopic lingual mucosa graft ureteroplasty, both showed feasibility and safety (38,39). Evidence suggests that mucosa grafts not only facilitate successful reconstruction in complicated ureteral strictures but also holds promise for lower complication rates compared to other graft materials and methods (40,41). Since the novelty of this technique, no cohort study has been conducted; but we believe high-level evidence will emerge in the near future. In recent years, many urologists have increasingly turned to ureteroplasty with oral mucosal grafts and appendiceal grafts, for the purpose of promoting the treatment of complex ureteric strictures in the proximal or middle segment, thereby avoiding ileal substitution and autogenous kidney transplantation (22,24,34,35). Searching for new substitutes to replace the ureter will still be a hot area in the field of ureter reconstruction.

Moreover, according to the theme of the T100 papers, many articles mainly focus on robotic assisted reconstruction. Despite the sharp learning curve and higher expenses, robot-assisted reconstruction not only has the direct benefit of reducing the total size of incisions needed, such as leading to lower recurrence rates and improved aesthetic outcomes, as well as potentially faster recovery, but it can also handle various pelvic pathologies (42-46). Additionally, robot-assisted technology can be used in multiple surgical approaches, such as anastomosis, ureteral reimplantation, oral mucosa graft ureteroplasty, ileal replacement, and autologous kidney transplantation (27). Studies demonstrate a significant trend towards the incorporation of robotic techniques in ureteroplasty, showcasing their effectiveness as a safe alternative to traditional open surgery approaches (47,48). Clearly, as the use of robotic surgeries expands rapidly, better methods and standards should be developed and implemented to fully utilize the potential of robotic technology in medicine, especially surgery, to achieve better results in surgical outcomes and prognosis (49-51).

Advantages and limitations

The study utilized WOSCC, a reputable and extensively used academic database, ensuring dependable and precise research outcomes through high-quality sources. This approach also minimizes issues related to formatting inconsistencies and duplicate entry issues. In addition, by revealing current research hotspots and developmental trends, the study offered valuable insights that help scholars better plan and conduct future research, thus strengthening the relevance and influence of its findings. Despite being able to analyze the 100 most cited papers on ureteral stricture reconstruction in this report, we still have some limitations. For example, we only focused on highly cited articles, which may have lost some novel or equally valuable literature with low citation rates due to recent publication years, including some papers related to lingual mucosa grafts. Future bibliometric studies could incorporate broader inclusion criteria to avoid this shortcoming. Excluding conference papers, technical reports, preprints and sources beyond WOSCC may also limit the ability to capture emerging trends. Additionally, as the first bibliometric article in this field, articles with lower citation counts were not included in the analysis. Lastly, ureteral stricture is not a common disease (2,3), further multicenter and high-volume studies are urgently needed, especially those that focus on robot-assisted surgery and mucosa grafts.

Conclusions

This study is a bibliometric analysis of the T100 papers of ureteral stricture reconstruction, offering evolving directions and prominent areas of interest within this research field. The analysis revealed the leading contributors in terms of countries, institutions, and researchers. Additionally, current and emerging focal areas were identified, such as robot-assisted surgery and mucosa grafts. Institutions from the USA and China lead in this area of research, but the international cooperation is relatively few which need to be strengthened. The three most productive authors include Daniel D. Eun, Ziho Lee, and Xuesong Li. Our study offers meaningful insights into the evolution of ureteral stricture reconstruction, offering potential benefits to researchers, academic institutions, healthcare facilities, and policy makers.

Supplementary

The article’s supplementary files as

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.