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Neurospine Search


Liu, Kotheeranurak, Quillo-Olvera, Facundo, Sharma, Suvithayasiri, Jitpakdee, Lin, Mahatthanatrakul, Jabri, Khandge, Aher, Wu, Ho, Wong, Wing, Akbary, Patel, Pakdeenit, Chen, Lokanath, Jaiswal, Suen, Hasan, Sabal, and Kim: A 30-Year Worldwide Research Productivity of Scientific Publication in Full-Endoscopic Decompression Spine Surgery: Quantitative and Qualitative Analysis



The ever-growing number of articles related to full-endoscopic spine surgery published in the last few decades presents a challenge which is perplexing and time-consuming in identifying the current research status. The study aims to identify and analyze the most cited works related to full-endoscopic decompression spine surgery, compare the articles published by different publishers and area, and show the current publication status of full-endoscopic research.


Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science database between 1992 and 2022. Spine has the highest H-index with the most-cited journal in the field of full-endoscopic decompression spine surgery. China ranked as the most productive country, whereas the most cited with high H-index papers came from South Korea. For the author analysis, Yeung AT, Ruetten S, Hoogland T, Ahn Y, Choi G, and Mayer HM were the most impactful authors in the global and local citations. The most productive organization is Wooridul Spine Hospital.


The bibliometric study showed a growing trend of research on full-endoscopic decompression spine surgery over the past 30 years. It has demonstrated that there is a significant increase in the number of authors, institutions, and internationally collaborated countries. However, the quality of studies is still low, and the lack of high-quality clinical evidence and the trend of general journal submissions has somewhat affected the quality of endoscopy journals in recent years.


The ongoing coronavirus pandemic pneumonia (severe acute respiratory syndrome coronavirus-2, SARS-CoV-2) has spread rapidly worldwide all over the world for more than 2 years since its nomenclature by World Health Organization [1]. Due to its spread around the world, the low cost of postoperative care is a critical need and the clinical care models have gradually changed to accommodate the new healthcare environment. For this reason, so minimally invasive spine surgery as one of the solutions for clinical practice has been attracted by medical decision-makers due to its shorter perioperative period with less approach-related morbidity than traditional spine surgery [2]. In recent decades, the interest in microscopic and endoscopic surgery has been grown in growing in both developing and developed countries, especially rising fast in the area of full-endoscopic procedure. The ever-growing number of articles related to full-endoscopic technique published recently and present a challenge that is perplexing and time-consuming to recognize the high-impact papers.
The rapid development of modern information technologies significantly influences medical treatment and public health, and knowledge management in clinical medicine has provided new approaches and possibilities. The discipline of “Bibliometry” can be traced back to the beginning of the last century. It is a statistical method branch of information science that combines linguistics, information, and statistics [3]. This bibliometric method can measure the information distribution models via quantitative and qualitative analysis of a particular research area from published journals. In general, the cited times were considered as a determined measurement of the impact of an author, article, or journal. After that, by conducting scientific mathematical methods for data integration and processing, the evolution of the selected research direction could be revealed and help to predict valuable future research directions [4]. The present study aims to demonstrate the bibliometric analysis of the fullendoscopic spine decompression surgery publications and illustrate the research trends with visible scientific mapping. We also investigate the cost and resource allocation of each author’s country’s National Health System and discuss the impact of their likely willingness to submit to journals.


1. Search Strategy

In our cross-sectional bibliometric analysis research, a thirtyyear timespan of literature was searched on the Web of Science Core Collection database based on the modified evidence-based Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) guidelines [5]. Our team performed the search with the “Topic” search function to search the title, abstract, author keywords, and KeyWords Plus on the Web of Science (WOS). The search formula was referenced and designed based on the AOSpine Consensus Paper on Nomenclature for Working-Channel Endoscopic Spinal Procedures of Full-endoscopic Decompression [6] as follows: (endoscopy* or arthroscopy*) and (“Discectomy” or “foraminotomy” or “diskectomy” or “laminotomy” or “disc surgery” or “disc herniation” or “disk herniation” or “foraminoplasty” or “nucleotomy” or “facetectomy” or “flavectomy” or “decompression” or “transforaminal” or “interlaminar”) and (spine or spinal or lumbar or cervical or thoracic). In this research, all the data was publicly available and not necessary for protected health information. Therefore, Institutional Review Board approval was not sought from our university. The study search strategy referenced the PRISMA guideline, and the reports followed the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) reporting guideline for crosssectional studies [7].

2. Eligibility Criteria

We included English-language articles published in all indexed journals from January 1992 to October 2022. Two reviewers (YT and FV) screened the records independently for eligibility. The screening process had 2 stages. First, we screened the titles and abstracts obtained in the database search results to find relevant studies based on the criteria. Articles not accordant with the following inclusion criteria were excluded: Our search criteria included full-endoscopic clinical prospective/retrospective, randomized/nonrandomized, cohort-controlled studies; case series; case reports; technique reports; full-endoscopic relative basic studies such as finite biomechanical analysis. Other endoscopic techniques, such as biportal-endoscopy, epiduroscopy, joint surgery, microendoscopy, neuroendoscopy, laryngoscopy, thoracoscopy, or non-original articles, such as reviews, proceeding papers, editorial materials, early access, letters, corrections, and conferences, were excluded from this study. The selected publications were thoroughly investigated, and relevant details were recorded. Second, we did cross-checking, testing, and processing of the raw data on the 3 bibliometric software to ensure the various raw formats (.txt; BibTeX Database) and these were fully recognized and analyzed. Any disagreements were resolved through discussion involving a senior author (JS) to make a final consensus.

3. Bibliometrics Analysis

In our study, 3 professional bibliometric software (Bibliometrix 4.0.0 [8], Citaspace 6.1.R3 [9], and VOSviewer 1.6.18 [10]) were used for data processing. No software is superior to the others in every aspect. Therefore, the various most valuable elements of the 3 software were discussed and then used separately in our research for different analyses. Bibliometrix (University of the University of Naples Federico II, Naples, Italy) was an R-studio package from the bibliographic database for performance bibliometric analysis. VOSviewer 1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, The Netherlands) is a free software tool for drawing graphical representations of bibliometric maps to construct and visualize the bibliometric networks which used to create a keyword co-occurrence network, overlay, and density visualization map in this study. It is based on the bibliographic data unit of the author keywords or KeyWords Plus. The correlation relationship between different units was measured by total link strength (TLS). CiteSpace is a Java application for analyzing and visualizing the scientific literature's bibliometric character for analyzing an institution’s contribution, decomposing a network into clusters, and creating dual-map thematic overlays on global maps of science [9,11]. Figures used for knowledge visualization consist of nodes and links. Each node in the diagram represented one element, such as the institution or cocited reference. The size of each node indicated the occurrence frequency, the lines between the nodes suggested a co-occurrence or cocitation link, and the varying colors of the circles from the inner to the exterior of the node represented the progression of time. Furthermore, we believe that the economic strength of the country and the percentage of investment in the health system may one of the potential crucial factors influencing the implementation of full-endoscopy development and publication. Therefore, we surveyed the selected country’s population, gross domestic product, current estimates of health expenditures, and distribution of medical personnel from the World Bank Open Data which compiles country-level statistical data using information from the statistical systems of member countries and free access.

4. Data Processing

In our research, the number of published articles was considered an index of the quantity of research productivity. The number of citations was considered a quality indicator. Compared to the previous bibliometric publications, we do not rank the results with numbers, only presenting the most influential items of authors, countries, and institutions on tables. Before putting together, the keyword trends and clusters in Bibliometrix, CiteSpace, or VOSviewer, we manually standardized the keywords by merging similar keywords that were similar and replacing keywords that had nothing to do with the research. This improved the validity and quality of the research. Moreover, an independent Java engineer (DX) built Java programs and used secondary filtering and other processing on the raw data to make it fit the expected design of the method. For example, regarding the author analysis, extracting and analyzing only the first author and corresponding author is not available through 3 bibliometric software or the WOS directly. Because of this, it is crucial to get the needed information from the raw document correctly.
The core journals of full-endoscopic decompression spine surgery (FEDS) are evaluated using Bradford’s law of scattering in descending order of the number of articles carried on the subject [12]. The first zone is the nucleus of journals devoted to the given subjects, publishing about a third of the journals in the entire collection. We gathered data from the citing journal and the cited journal to construct a visual dural map for assessing, comparing, and contrasting publishing portfolio features [13]. Moreover, our team designed a topic dendrogram to depict the object’s hierarchical relationship in FEDS research. It is generally obtained because of hierarchical clustering and is usually used to figure out the best way to allocate objects to clusters.
To find and describe the most-cited FEDS articles, as well as to compare the most-cited articles from the specialty journal and publisher (whether they are comprehensive or commercial publishers), the Scientific Information Web of Science’s Science Citation Index Expanded was used. We compared the top 3 most published established comprehensive publishers’ and open access (OA) or non-OA articles on the same metrics. The analysis was performed on the metrics with H-index, average per item (API), average citations per year (APY) and total number of citations (TC). In addition, we also divided the publishers into comprehensive and specific publishers according to the way they were established. For comprehensive publishers, such as Hindawi Publishing Group, MDPI, and Frontier Media Sa, these journals are peer-reviewed for multidisciplinary scientific publications. Conversely, specialized journals are often established by societies, specific or other medical special issues. The American Society of Interventional Pain Physicians, Thieme Medical Publishers, and the American Association of Neurological Surgeons are a few examples.

5. Statistical Analysis

The Stata 16.0 (Stata Corp., College Station, TX, USA) was used for all statistical analyses, and Microsoft Excel 2016 (Microsoft Corporation, Redmond, WA, USA) was used to analyze and present the data. For statistical analysis, 2-sample Wilcoxon rank-sum (Mann-Whitney) tests and Kruskal-Wallis H-tests were used to compare the TC and the average number of citations per year between OA and non-OA, the most published publisher and comprehensive with specific publishers. ShapiroWilk test and normal quantile plot for determining the normality of data distribution. After applying Levene's test for variance, Mann-Whitney U was used. The Pearson correlation coefficient test (r) determined the statistical significance of correlations. Statistical significance was defined as a p-value of 0.05.


1. Descriptive Statistics of Bibliometric Analysis

The WOS database search returned a total of 2,291 records. After manually reviewing the titles and abstracts of records on the marked list, 314 articles that did not meet the inclusion criteria were excluded. In conclusion, 990 FEDS-related studies that met the search criteria were included in the present bibliometric analysis (Fig. 1). The number of authors is 2,306, with 9.39% international coauthorships from 43 countries contributing to the growth of the FEDS research field. The average number of authors per paper with multiple authors is 5.57. Each article comes from one of 147 journals or books. The number of citations per article is 14.84, and there are a total of 10,469 references. The number of articles published between 2016 and 2021 increased by 128.1 per year. The number of articles published recently years has increased by more than eightfold from 2010 to 2015. The annual growth rate was calculated using the compound annual growth rate, and the average annual growth rate of FEDS research’s scientific output will be 17.22% until the beginning of 2022 (Table 1).

2. Bibliometric Analysis of Country and Institute Contribution

The world map of worldwide research productivity is illustrated in Fig. 2. The color’s intensity and the red line’s density indicate the number of articles published and the frequency of international collaborations, respectively. There are 10 major producing countries, with at least 10 papers published in each of them. China, South Korea, and the United States were the most productive regions (Table 2). Among the 43 countries with publications, South Korea (t= 4,970), China (t= 3,896), Germany (t = 2,295), and the United States (t = 2,237) achieved the most-cited counts. Moreover, the relatively higher API and H-index in Germany, Korea, and the United States represent the average publication of high-quality articles. The highest citation average per article was from Germany (t = 47.6), followed by the United States (t= 24.6) and South Korea (t= 24.0), respectively. The lower multiple country publications ratio, which indicates the lower rates of multinational cooperation research, is likely to be found in China, Japan, and India. As shown in the Fig. 3A, a total of 831 institutions published articles on FEDS with closer cooperation between each other. Among these, the Wooridul Spine Hospital (n= 50, 5.05%) is leading in terms of output, followed by Tongji University (n = 41, 4.14%), Brown University (n = 29, 2.92%), Seoul St. Mary’s Hospital (n = 34, 3.43%), and Lifespan Rhode Island Hospital (n= 48). Moreover, high-income countries’ publications of FEDS articles and health system expenditure costs were higher compared to the upper and lower middle-income countries. We also found that the percentage of clinical caregivers showed very high correlations with health expenditure (r= 0.915, p≤ 0.001).

3. Bibliometric Analysis of Journal Contribution

The influential impact journals are illustrated in Fig. 2. In our research, the Spine has the highest H-index (n= 22) and is the most-cited (t= 2,864) journal with the earliest publication year (1994) and consider as the most influential impact journal. World Neurosurgery published the most significant number of FEDS research articles (n= 162), followed by the Pain Physician (n= 55) and Spine (n= 34) on the FEDS. Among of them, World Neurosurgery, Pain Physician, Spine Medicine, and European Spine Journal have been identified as the most essential and fundamental journals. In addition, the number of Spine articles among the top 10 most-cited articles is as highest as 7. From the dual-map overlay visualization of journal-to-journal citation, we revealed that the FEDS authors most frequently cite the journal in the areas of medicine, clinical, neurology, and sports; and usually cited by the scope of nursing, rehabilitation, psychology, education, social, economic, political research, respectively (Fig. 3C).

4. Bibliometric Analysis of Author Contribution

According to the citation analysis (including the first and corresponding author), Kim HS is the most prolific author. AHN Y has the greatest H-index and G-index of all the authors, and his FEDS paper in FEDS received the most citations with highest fractionalized score (Fig. 4). According to our data, Lee SH and Ahn Y were the authors with the longest period of continuous publication, from 2003 to 2022. Telfian AE and Kim HS authored a large number of articles with high citations in 2016 and 2018, respectively. Moreover, Yeung AT, Ruetten S, Hoogland T, Ahn Y, Choi G, and Mayer HM’s papers are the most impactful according to the global and local bibliometrics analysis (Supplementary Material 1). These articles are highly influential in spinal endoscopy and are also widely referenced in other subdisciplines or disciplines, indicating that other researchers serve them as spine endoscopic flagship for their research. In addition, the 3 field plots highlight the most productive authors’ intellectual origins and research orientation.

5. Bibliometric Analysis of Keywords and Reference Assemblies

A total of 150 keywords were considered in the network analysis (Figs. 5, 6). The 3 frequently co-occurrence keywords are “discectomy” (TLS= 1,663; occurrences= 346), “disc herniation” (TLS= 1,456; occurrences= 281), and minimally invasive spine surgery (TLS= 978; occurrences= 198). In cluster analysis, we obtained 10 different clusters from the analysis. Cluster 1 (color red) enrolled 28 units related to the general terminology of full-endoscopic approach, technique, and indication, such as transforaminal approach, laminotomy, and stenosis. Cluster 2 (color green) enrolled 22 units related to the full-endoscopic application terms at the cervical level, such as transcorporeal approach, foraminotomy, and instrumentation. Cluster 3 (color blue) enrolled 19 units related to the comparison to microscopic surgery, such as microdiscectomy, recurrence, and cohort trial. Cluster 4 (color yellow) enrolled 17 units related to the focus terms of early technology, such as arthroscopic microdiscectomy, chemonucleolysis, and multifidus muscle. The other clusters from 5 to 10 describe other aspects of endoscopic techniques that are classified separately, such as anesthetic modalities, adjunctive techniques, anatomy, etiology, or complications. From the overlay visualization, we obtained the recent 10 years of mainstream research areas of anesthetic methods, cost-effective analysis, and cervical or thoracic applications. The density visualization shows the greatest weight of research directions with transforaminal, interlaminar, complications, and spinal stenosis surrounding the lumbar discectomy. Moreover, based on the line chart of annual publications and average citations per year, the jump in 2015 was the turning point of production (Fig. 7). In addition, the most influential articles in the field of FEDS are shown in Table 3.

6. Bibliometric Analysis of Various Classifications by Type of Journal or Publisher

Non-OA, Lippincott, and specific publisher shows the highest H-index, API, TC, and APY. The proportion rate of OA was highest in the comprehensive journal (as higher as 87.6%). China is the most productive country that contributes to specific and comprehensive publishers. Conversely, South Korea, and the United States shows a higher proportion of publication in a specific publisher. Wooridul Spine Hospital is the highest contribution to the specific journal, whereas Tongji comprehensively shows the highest contribution to the comprehensive journal.
The publication number of these journals was differentiated according to the different OA or professional attributes (Fig. 8). The differences in TC and APY between the OA and non-OA are statistically significant between each other (Z= -6.964, p< 0.05; Z= -5.760, p< 0.05), as shown in Table 4. The number of TC and APY citations for OA and non-OA is also considered different. There is no statistical difference in APY times between the 3 most productive publishers (χ2= 5.654, degrees of freedom [df]=2, p>0.05); however, it can be assumed that the APY counts of the 3 different journals are not all the same (χ2= 15.252, df= 2, p< 0.001). Based on the statistical test results, the difference between Elsevier and Springer Nature is not statistically significant (rank means: 12.62, p= 0.198). However, the difference between the TC of Lippincot Williams & Wilkin’s and Elsevier (rank means: 57.15, p< 0.05); and between Lippincot Williams & Wilkin’s and Springer Nature (rank means: 69.77, p< 0.05); are statistically significant. The differences in TC and APY between the comprehensive and specific journals were statistically significant (Z = 6.944, p < 0.001); (Z = 5.765, p < 0.001). It can still be considered that the number of citations of TC and APY for specific publishers and comprehensive publishers is significantly different.


In this research, we have manually screened and double-checked all results to find any calculation biases inherent in the software used to perform the analyses. We discovered that when the software identifies the name of authors, it aggregates and analyzes the data of all the individual authors of that abbreviation from a bibliometric file, resulting in analytical inaccuracies. The software cannot determine the difference between authors’ names with abbreviations. The WOS or bibliometric software automatically recognizes the abbreviation name, which causes a statistical error when doing the analysis. In our study, we filtered the data, and only the first and corresponding authors were included in our analysis. Meanwhile, we observed that an analysis based just on the number of coauthors would be biased concerning the contribution of authors to the actual research field. Therefore, we believe that the first and corresponding authors tend to contribute the most to clinical endoscopic studies. To the best of our knowledge, similar inaccuracies may have occurred in the published statistics of the past. As a result, the quality of analysis for identical bibliometric findings can vary when using different software. Thus, we selected the high-quality elements from each software for data analysis.
According to our knowledge, the preliminary form of the Fullendoscopic technique was earlier applied at 1993. Then, it has been developing rapidly and published high cited flagship articles which reported with high-safety surgical access and technical improvements. Recently, the areas of interest primarily explore technique indications or collect high-quality clinical evidence. Among of them, before 2015, the Germany, South Korean, the United States contributions as pioneers of FEDS research in spine surgery, followed by the entry of China led to a substantial increase in literature publication. Moreover, from our analysis results of references spectroscopy, the history of publication illustrates that the first 3 peaks from Mayer, Yeung, Rutten, Choi from the 1993 to 2007. They are the pioneer of the Full-endoscopic research which provide solid evidence for the crucial clinical considerations and practice of spinal endoscopic surgery; however, then there is no peak continues to appear after them. We found that even though the number of endoscopic studies published now is more significant than in the past, the citation rate of endoscopy-related papers continues to decline. This, of course, cannot be separated from the precipitous decline in average citations in the literature in the last 2 years impacted by the severe acute respiratory syndrome coronavirus-2. But the more important question is that although various endoscopic novel assisted techniques described recently, such as O-arm navigation system, robots-assisted technique, the high cost blocks the step of other clinicians to replicate despite the popularity.
It is essential to identify demographic risk factors for degenerative spinal conditions to understand the risk, prevention, treatment, and outcome of spinal injuries and distinguish between acute injuries and degenerative disorders [14]. In our study, the topic dendrogram revealed the hierarchical relationship between objects in FEDS research. It shows that the surgical treatment method of myelopathy is related to the nearby bony ossification or ligamentum flavum hypertrophy. Furthermore, disc herniation also indicates a solid connection to radiculopathy. As we understand, reherniation is the most common reason for surgical revision in patients after endoscopic surgery [15]. Thus, it is crucial to consider preoperative risk factors for the patient’s prognosis, such as the characteristics of the pain generator; herniation size and location; patient's comorbidity; or the access problems due to the patient’s excessive obesity or adjacent anatomical tissue obscuring the access itself (e.g., patients with higher iliac wings than usual) [16]. Furthermore, we found that the FEDS research focuses on the impact of biomechanical instability, which is closely linked to the fusion study. In addition, microscopic surgery is strongly associated with endoscopic surgery, primarily since microscopy is frequently used as a revision surgical approach to endoscopic surgery. Likewise, endoscopic surgery through the transforaminal approach can also be used as a solution for revision surgery after microsurgery [17]. Full-endoscopic technique avoids tissue scar adhesions caused by the same approach. At the same time, the magnified view of full-endoscopy improves the surgical view and the safety of nerve tissue stripping during revision surgery. Lastly, due to the steep learning curve in endoscopic surgery, early endoscopic clinicians are frequently advised to select the transforaminal approach as the primary case for adaptation to endoscopic techniques [18].
We have discovered that many OA articles exist in the included studies. Therefore, the statistical analysis on the various classification of journal type and publisher was conducted and found that the non-OA articles usually have a higher impact than OA articles on the H-index, API, TC, and APY. We discovered that Elsevier published the most articles among the 3 most productive publishers, followed by Springer Nature and Lippincott, respectively. However, Springer Nature is related to relatively lower quality of papers, as shown in the evaluated metrics. Although Lippincott has published the lowest number of articles, their papers have a relatively high quality. Furthermore, comparing the comprehensive and specific journals, the latter shows far exceeds the quality of prior journals. Among them, China has the highest number of publications in both types of journals but with a higher number of publications in the comprehensive journal. Comparatively, researchers in South Korea and the United States prefer more than specific journals for their publication. This may also contribute to more government spending on the healthcare sector, as usually seen in high-income nations, as well as the comparatively high number of specialists and nursing staff, which enables physicians to focus more on high-quality clinical research.
Here comes another interesting question. Initially, the original purpose of OA was to make it easier for academics to undertake more collaborative research publicly and to permit more researchers to study and cite more publications without being restricted by a paywall, hence accelerating the speed of overall clinical research. However, we found that the general assessment indicators of quality from the OA articles are lower than nonOA articles in the area of FEDS. The reasons could be the following. As is well known, comprehensive publishers frequently use the article processing charge publication model. Nonetheless, this pricey strategy can still not deter endoscopic researchers from submitting their findings. Although many of these comprehensive publishers are indexed in the WOS and have high-impact factors, a high-frequency rate of fast turnaround times and a high acceptance rate make the quality of its review doubtful. Our research results confirm this skepticism. Even though many papers are published among the high-impact factors journals, the quality of the publication from comprehensive journals is worrisome. Unsurprisingly, innumerable early-career academics choose these publishers over the more reputable ones to speed up their publication in the journal with the highest impact factor possible. These researchers could be poisoned and captivated by incentives from institutions or countries, as they could boost their citation rank among the professionals in a short time as opposed to the quality of their work. Therefore, using impact metrics alone to evaluate the quality of an article related to FEDS seems inappropriate.
We have some limitations in our research. Firstly, our bibliometric analysis was only the extracted data from the WOS core collection database, which may cause source bias. Secondly, since the dissemination of the article and the efficacy of the technique require practice to demonstrate, we regret that we were unable to uncover very recent articles of high quality and potential through our research. These could also reflect the significant influences despite the short-term development of FEDS. However, technologically advanced research typically generates most discussions after 2 years; recent papers published in 2020 and prior have yet to create much-heated discussions. It is also possible that the lack of the appearance of papers related to clinical decision-making with available clinical options or a wide publication base to bury the data of high-quality papers. Finally, since our search strategy was designed and implemented in the middle of the year, it is impossible to generate a descriptive statistic for the articles published later that year. In this instance, we have modified some of the statistical analyses in our research, such as calculating the growth rate solely through the beginning of 2022.


The bibliometric study showed a growing trend of research on FEDS over the past 30 years. The number of authors, institutions, and internationally collaborated countries have been significantly increased, but high-quality studies are still lacking. However, a paradigm shift is emerging in a recent series of publications as the higher-quality studies including meta-analysis or attempts to develop standard guidelines have been increasingly published. This indicated that full-endoscopic spine surgery is gradually reaching its maturity.

Supplementary Material

Supplementary Material 1 can be found via https://doi.org/10.14245/ns.2245042.521.
Supplementary Material


Conflict of Interest

The corresponding author, Jin-Sung Kim, is a consultant of Richard Wolf, GmbH, and Elliquence, LLC. The other authors have no conflicts of interest to declare.


This research is supported by a grant from Korea’s Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health & Welfare, Republic of Korea (Grant Number: HC20C0163).

Author Contribution

Conceptualization: YL, VK, JQO, KJ, HJ, AVK, NMW, YKL, JLK; Data curation: YL, VIF, S Sharma, S Suvithayasiri, RBA, AWH, KKP, BP, MSJ; Formal analysis: YL, LAS; Funding acquisition: JLK; Methodology: YL, VK, VIF, KJ, GL, MW, NMW, LSW, KA, KKP, BP, MSJ, JLK; Project administration: S Sharma, AVK, K Akbary, TKS, JLK; Visualization: YL, AM, HJ, LSW; Writing - original draft: YL, VIF, S Sharma, S Suvithayasiri, KTC; Writing - review & editing: YL, VK, JQO, VIF, S Sharma, S Suvithayasiri, KJ, GL, AM, AVK, RBA, MW, AWH, NMW, LSW, KA, KKP, BP, KTC, YKL, MSJ, TKS, LAS, JLK.


We would like to acknowledge all of endoscopic spine surgeons’ contribution in the development of endoscopic technique. And acknowledge an independent Java engineer (DX) built specific Java programs for data filtering and processing.

Fig. 1.
Flowchart diagram illustrating the included articles included in the bibliometric analysis.
Fig. 2.
World map showing the distributions of publications. The color intensity is proportional to the number of publications, and the red line is the relationship of country collaboration.
Fig. 3.
(A) Collaboration analysis of institute analysis by the CiteSpace. (B) Pathfinder network of cluster analysis from cited reference on the research of FEDS. (C) dual-map overlay visualization of journal-to-journal citations that cited FEDS. The arrow of a citation points from citing journals (left) to cited journals (right). FEDS, full-endoscopic decompression spine surgery.
Fig. 4.
The timeline of the most productive authors was calculated by the author’s consecutive production over time. The bubble size is the proportional to the number of articles, and the color intensity of bubble is the proportional to the total citation per year. TC, total citation; PY, publication year.
Fig. 5.
(A) The word cloud visualizes various words with different font sizes based on the KeyWords Plus, more crucial words will appear at the central of the cloud with larger size. (B) Network visualization: the higher the weight of an item, the larger the label and the circle of the item. The distance between 2 units in the visualization approximately indicates the relatedness of the unit in terms of cocitation links. The closer 2 unit are located to each other, the stronger their relatedness.
Fig. 6.
(A) High-frequency terms and their burst time. The size of circle represents the strength of the burst. (B) The topic dendrogram is a diagram that depicts the full-endoscopic decompression spine surgery research hierarchical relationship.
Fig. 7.
(A) Annual scientific production. (B) Average article citation per year. (C) Reference publication year spectroscopy. Black line: number of cited references per year; red line: deviation from the 5-year median.
Fig. 8.
Stacked area graph of different classification by journal type. OA, open access.
Table 1.
Basic information about the bibliometric dataset
Description Results
Software and analyzes
Bibliometrics: Biblioshiny & Web of Science: Citation report Basic analysis: total number of publications, annual grouth rate, 3 fields plot, etc.
Impact of the author (first and corresponding author), countries, institutions, journal
Annual scientific production
Keywords (plus), citation analysis (reference spectroscopy)
General versus specific publisher analysis
CiteSpace Document cocitation institute and clusters visualization
Dural map overlay of journals
Time map of clusters
VOSviewer Keyword co-occurrence network map
World Development Indicators Country development data
Main information about data
Timespan 1992:2022
Sources (journals, books, etc.) 147
Documents 990
Authors 2,306
Annual growth rate 17.22%
Country 43
Document average age 4.39
Coauthors per doc 5.57
Average citations per doc 14.84
International coauthorships % 9.39
References 10,469

The coauthors per articles index is calculated as the average number of coauthors per article; the collaboration index is a coauthors per article index calculated only using the multiauthored article set which calculated as total authors of multiauthored articles/total multiauthored articles.

Table 2.
Country’s impact of FEDS publications and country’s medical resources distribution
Item No. (%) API* H-index SCP MCP MCP_ratio GDP/POP. (T$/M, 2021) Health expen- diture (T/$, % of GDP, 2019) Physicians/nurs- es (per 1000 peo- ples) (2014-19) Income level
China 516 (52.4) 7.0 26 516 22 0.04 17.7 (1,412.6) 0.96 (5.4) 2.0/2.7 Upper middle income
Korea 212 (21.4) 24.0 40 174 32 0.16 1.8 (51.7) 0.15 (8.2) 2.4/7.5 High income
United States 109 (11.0) 24.6 26 64 18 0.22 23.0 (331.9) 3.86 (16.8) 2.6/15.7 High income
Germany 51 (5.6) 47.6 20 33 4 0.11 4.2 (83.1) 0.49 (11.7) 4.3/13.5 High income
Japan 41 (4.1) 7.3 9 35 1 0.03 4.9 (125.7) 0.52 (10.7) 2.5/12.7 High income
Turkey 21 (2.1) 10.8 7 19 2 0.10 0.8 (85.0) 0.03 (4.3) 1.8/3.0 Upper middle income
Netherlands 17 (1.7) 15.9 9 5 4 0.44 1.0 (17.5) 0.10 (10.1) 3.7/11.5 High income
India 14 (1.4) 7.4 5 9 0 0 3.1 (1,393.4) 0.09 (3.0) 0.9/2.4 Lower middle income
Brazil 11 (1.1) 3.0 3 4 1 0.20 1.6 (214.0) 0.15 (9.6) 2.3/7.4 Upper middle income
Italy 10 (1.00) 5.8 5 8 0 0 2.1 (59.1) 0.18 (8.7) 8.0/5.9 High income

FEDS, full-endoscopic decompression spine surgery; API, average per item; SCP, single country publications; MCP, multiple country publications; GDP, gross domestic product; POP, population.

* Average for each item represents the overall results set’s average number of cited articles. It is calculated by dividing the total number of results in the set by the times cited count.

Table 3.
The most influence articles in the field of full-endoscopic decompression spine surgery
No. Title Authors Source Year Citations APY
1 Posterolateral endoscopic excision for lumbar disc herniation - Surgical technique, outcome, and complications in 307 consecutive cases Yeung AT, Tsou PM Spine 2002 430 20.48
2 Full-endoscopic interlaminar and transforaminal lumbar discecto- my versus conventional microsurgical technique - A prospective, randomized, controlled study Ruetten S, Komp M, Merk H, Godolias G Spine 2008 418 27.87
3 Percutaneous endoscopic discectomy: surgical technique and pre- liminary results compared to microsurgical discectomy Mayer HM, Brock M JNS 1993 275 9.17
4 A prospective, randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdis- cectomy Hermantin FU, Peters T, Quartararo L, Kambin P JBJS 1999 199 8.29
5 Transforaminal posterolateral endoscopic discectomy with or without the combination of a low-dose chymopapain: A prospec- tive randomized study in 280 consecutive cases Hoogland T, Schubert M, Miklitz B, Ramirez A Spine 2006 198 11.65
6 Full-endoscopic cervical posterior foraminotomy for the operation of lateral disc herniations using 5.9-mm endoscopes - A prospec- tive, randomized, controlled study Ruetten S, Komp M, Merk H, Godolias G Spine 2008 190 12.67
7 Use of newly developed instruments and endoscopes: full-endo- scopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach Ruetten S, Komp M, Merk H, Godolias G JNS 2007 185 11.56
8 Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: Surgical technique, outcome, and prognostic factors of 43 consecutive cases Ahn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY Spine 2004 184 9.68
9 Percutaneous endoscopic approach for highly migrated intracanal disc herniations by foraminoplastic technique using rigid work- ing-channel endoscope Choi G, Lee SH, Lokhande P, Kong BJ, Shim CS, Jung B, Kim JS Spine 2008 149 9.93
10 An extreme lateral access for the surgery of lumbar disc hernia- tions inside the spinal canal using the full-endoscopic uniportal transforaminal approach-technique and prospective results of 463 patients Ruetten S, Komp M, Godolias G Spine 2005 146 8.11

APY, average citations per year.

Table 4.
Statistical analysis of various classification by type of journal or publisher
Variable OA Non-OA p-value Elsevier Springer Nature Lippincott p-value Specific (≥5) General (≥5) p-value Specific (1993–2022) General (2015–2022)
No. 441 549 249 158 101 228 137
H-index 30 50 26 23 30 35 12
API (time) 8.83 19.81 11.17 12.23 40.49 19.19 4.2
OA (%) N/A N/A 5.6 (14/249) 58.2 (92/158) 45.4 (46/101) 43.0 (98/228) 87.6 (120/137)
TC (P25–P75, time) 3 (0–9) 7 (2–20) ≤0.05 6 (2–12) 4 (1–14) 10 (3–39) ≤0.05 6 (1–22) 2 (0–5) ≤0.05
APY (P25–P75, time/yr) 0.86 (0–1.86) 1.5 (0.5–2.86) ≤0.05 1.33 (0.5–2.5) 1.225 (0.5–2.38) 1.75 (0.67–4.07) 0.059 1.4 (0.5–3.0) 0.5 (0–1.3) ≤0.05
Country (%) China (37.28) China (83.94)
South Korea (29.83) South Korea (11.68)
USA (16.27) USA (3.65)
Affiliation (%) Wooridul Spine Hospital (7.90) Tongji Univ. (5.84)
Tokushima Univ. (5.26) Capital Medical Univ. (5.11)
Seoul St. Mary's Hospital (4.825) Chongqing Medical Univ. (5.11)

OA, open access; API, average per item (times cited); APY, average citations per year.

Publishers at least 5 publications are selected from general (comprehensive) journal or specific journals.


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