pISSN 2005-9159
eISSN 2093-0569

Clinical Research Article

Korean J Pain 2021; 34(1): 82-93

Published online January 1, 2021 https://doi.org/10.3344/kjp.2021.34.1.82

Copyright © The Korean Pain Society.

The evolution of the regional anesthesia: a holistic investigation of global outputs with bibliometric analysis between 1980-2019

Selcuk Kayir1 and Alperen Kisa2

1Department of Anesthesiology and Reanimation, Hitit University Faculty of Medicine, Çorum, Turkey
2Department of Anesthesiology and Reanimation, Hitit University Erol Olcok Training and Research Hospital, Çorum, Turkey

Correspondence to:Selcuk Kayir
Department of Anesthesiology and Reanimation, Hitit University Faculty of Medicine, Cepni Mah. Inonu Cad. No:176 19040 Çorum, Turkey
Tel: +90-505-3735158
Fax: +90-364-2193000
E-mail: drskayir@gmail.com

Handling Editor: Jeong-Gill Leem

Received: June 23, 2020; Revised: September 19, 2020; Accepted: September 22, 2020

Background: This study used bibliometric analysis of articles published about the topic of regional anesthesia from 1980-2019 with the aim of determining which countries, organizations, and authors were effective, engaged in international cooperation, and had the most cited articles and journals.
Methods: All articles published from 1980-2019 included in the Web of Science database and found using the keywords regional anesthesia/anaesthesia, spinal anesthesia/anaesthesia, epidural anesthesia/anaesthesia, neuraxial anesthesia/anaesthesia, combined spinal-epidural, and peripheral nerve block in the title section had bibliometric analysis performed. Correlations between the number of publications from a country with gross domestic product (GDP), gross domestic product (at purchasing power parity) per capita (GDP PPP), and human development index (HDI) values were investigated with the Spearman correlation coefficient. The number of articles that will be published in the future was estimated with linear regression analysis.
Results: Literature screening found 11,156 publications. Of these publications, 6,452 were articles. The top 4 countries producing articles were United States of America (n = 1,583), Germany (585), United Kingdom (510), and Turkey (386). There was a significant positive correlation found between the GDP, GDP PPP, and HDI markers for global countries with publication productivity (r = 0.644, P < 0.001; r = 0.623, P < 0.001, r = 0.542, P < 0.001). The most productive organizations were Harvard University and the University of Toronto.
Conclusions: This comprehensive study presenting a holistic summary and evaluation of 6,452 articles about this topic may direct anesthesiologists, doctors, academics, and students interested in this topic.

Keywords: Anesthesia, Conduction, Anesthesia, Epidural, Anesthesia, Spinal, Anesthesiologists, Bibliographies as Topic, Bibliometrics, Gross Domestic Product, Nerve Block, Publications.

Regional anesthesia is defined as a temporary removal of nerve conduction and pain senses in certain regions of the body with local anesthetic medications without causing loss of consciousness [1]. When regional anesthesia is compared with general anesthesia, the frequency of use is increasing, due to early mobilization, high analgesia level, shortened hospital stay, and lower postoperative nausea and vomiting [2]. Additionally, due to the increase in the use of ultrasonography, currently, regional anesthesia techniques are performed more reliably and effectively [3]. Though it is commonly believed that regional anesthesia is more reliable than general anesthesia, especially among elderly patients, no significant difference has been demonstrated between the two anesthesia types in terms of mortality and morbidity [4].

Bibliometric analysis is a method used to analyze the effect of research outputs like articles and book using quantitative measurements [5-8]. Bibliometric analyses may determine potential research cooperation between countries, organizations or authors in new and developing research areas [9-11]. Citation analysis analyzes how many times articles belonging to an author, country or journal are cited by others and reveals the effect of a certain author, country or journal in a certain field [12,13]. With the increase in publication numbers in recent times, many bibliometric analyses have been performed in the health field [5-13]. Articles included in common bibliometric analyses in these unique studies in the literature generally are found using databases like Web of Science, but also PubMed and Scopus.

Though the frequency of use of regional anesthesia, instead of general anesthesia, has been increasing in recent years, there is still no comprehensive bibliometric research about this topic in the literature. This study aimed to perform bibliometric analysis of articles published from 1980-2019 about the topic of regional anesthesia, to determine which countries, organizations, and authors are effective, international cooperation and most cited articles and journals in this field. Additionally, correlation analyses aimed to reveal factors affecting publication productivity. Keywords analysis aimed to determine current research areas and trends in relation to this topic.

Literature scanning was performed with the Web of Science (WoS: by Clavariate Analytics) database (access date: 23.08.2020). All articles containing the search keywords in the ‘Title’ section, published from 1980-2019 in the WoS database, had bibliometric analysis performed. The search keywords used the following codes: “regional anesthesia” or “regional anaesthesia” or “spinal anesthesia” or “spinal anaesthesia” or “epidural anesthesia” or “epidural anaesthesia” or “neuraxial anesthesia” or “neuraxial anaesthesia” or “combined spinal epidural” or “combined spinal and epidural” or “peripheral nerve block” Timespan: 1980-2019. Indexes: SCI-Expanded, SSCI, A&HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, ESCI. For bibliometric network visualization, the VOSviewer (version 1.6.13) program was used [14].

Statistical analyses used the SPSS version 22.0 (IBM Co., Armonk, NY) program. Normal distribution of data was tested with the Shapiro–Wilk test. The correlation analyses between the number of articles produced by countries with economic and development markers of gross domestic product (GDP), gross domestic product purchasing power parity (GDP PPP), and human development index (HDI) used the Spearman correlation analysis suitable for data distribution. Linear regression analysis was used to predict the number of publications in future years. P < 0.05 was accepted as statistically significant.

Literature screening found a total of 11,156 published items. Of these items, 6,452 were articles, 1,947 were letters, 1,372 were meeting abstracts, 505 were proceedings papers, 490 were reviews, and the remaining were other types of publication (390 publications; editorial materials, notes, corrections, book chapters, early access, news items, biographical items, book reviews, correction additions, retracted publications, books, discussions, reprints, retractions, items about an individual, data papers, and software reviews).

The research only performed bibliometric analysis of the 6,452 published articles. Of the 6,452 articles, there were a total of 107,533 citations (85,550 without self-citations), and the h-index of articles was 108, with average citations per item 16.67. Of the articles, 90% (5,815) were published in the English language. The remaining 10% were published in other languages (German [380], French [140], Portuguese [32], Russian [23], Spanish [21], Turkish [20], Czech [9], Korean [5], Dutch [2], Serbian [2], Chinese [1], Japanese [1], and Slovenian [1]).

1. Research areas

The top 15 research areas for the published articles were anesthesiology (4,120, 63.9%), general internal medicine (525, 8.1%), surgery (470, 7.3%), obstetrics and gynecology (380, 5.9%), critical care medicine (289, 4.5%), experimental medical research (177, 2.7%), veterinary sciences (176, 2.7%), orthopedics (166, 2.6%), clinical neurology (141, 2.2%), pediatrics (140, 2.2%), pharmacology/pharmacy (130, 2.0%), peripheral vascular disease (110, 1.7%), cardiac cardiovascular systems (97, 1.5%), urology nephrology (78, 1.2%), and neurosciences (74, 1.1%).

2. Development of publications and citations

The distribution of articles, according to year, is shown in Fig. 1. Additionally, the number of published items in future years, estimated with regression analysis, is given in Fig. 1. The estimated number of published items was 332 (263-400) for 2020, and 355 (258-453) for 2024.

Figure 1. Number of publications by years on regional anesthesia.

3. Active countries

The distribution of articles according to countries in the world is shown in Fig. 2. The active countries producing more than 100 articles were the United States of America (USA) (1,583), Germany (585), the United Kingdom (510), Turkey (386), Canada (338), India (315), Japan (307), France (298), China (289), Sweden (162), Australia (158), Italy (155), Finland (143), South Korea (130), Switzerland (130), Iran (129), Austria (110), and the Netherlands (103), in order. A total of 119 countries produced 6,452 articles. Of these countries, the network map showing international cooperation between the 50 countries with at least 10 articles is shown in Fig. 3.

Figure 2. World map for the publication productivity of worldwide countries on regional anesthesia.

Figure 3. Network visualization map for international collaboration of worldwide countries on regional anesthesia.

4. Correlation analysis

There were statistically significant level correlations found between the number of articles produced by countries on the topic of regional anesthesia with GDP, GDP PPP, and HDI (r = 0.644, P < 0.001; r = 0.623, P < 0.001, r = 0.542, P = 0.001).

5. Active journals

The 6,452 articles were published in a total of 1,015 journals. Among these journals, there were 50 with at least 15 articles about the topic. The top 50 journals produced most of the articles shown in Table 1. Additionally, the final column of the table shows the total citation numbers received by the journals and the mean citation number per article. The citation density map between these journals is shown in Fig. 4.

Table 1 Active journals on regional anesthesia

Anesthesia and Analgesia65422,17633.9Anasthesiologie & Intensivmedizin362627.3
Acta Anaesthesiologica Scandinavica3035,03916.6Canadian Journal of Anesthesia-Journal Canadien D Anesthesie2938613.3
Anesthesiology29514,62149.6Journal of Clinical and Diagnostic Research29451.6
Regional Anesthesia and Pain Medicine2677,22327.1Medicine291224.2
British Journal of Anaesthesia2628,59932.8American Journal of Obstetrics and Gynecology2888931.8
Anaesthesist2211,1125.0Journal of International Medical Research281595.7
Anaesthesia2104,27620.4International Journal of Clinical and Experimental Medicine27552.0
Canadian Journal of Anaesthesia-Journal Canadien D Anesthesie1733,50920.3Paediatric Anaesthesia2632812.6
International Journal of Obstetric Anesthesia1722,21212.9Turkish Journal of Anaesthesiology and Reanimation25451.8
Regional Anesthesia1572,67017.0Canadian Anaesthetists Society Journal2333714.7
Journal of Clinical Anesthesia1441,94313.5Indian Journal of Anaesthesia23512.2
European Journal of Anaesthesiology1201,73814.5Egyptian Journal of Anaesthesia21150.7
Anaesthesia and Intensive Care991,15111.6Journal of Arthroplasty2126512.6
Annales Francaises D Anesthesie Et De Reanimation885356.1Medical Science Monitor211065.0
Journal of Evolution of Medical And Dental Sciences-Jemds77100.1Pakistan Journal of Medical & Health Sciences2180.4
Journal of Anesthesia664486.8Obstetrics and Gynecology1968736.2
Revista Brasileira De Anestesiologia622504.0Saudi Journal of Anaesthesia18432.4
Anasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie601532.6Ja Clinical Reports1770.4
Journal of Cardiothoracic and Vascular Anesthesia4757412.2Korean Journal of Anesthesiology17513.0
Bmc Anesthesiology461743.8Pain Medicine1719511.5
Current Opinion in Anesthesiology431,01223.5International Anesthesiology Clinics1721212.5
Minerva Anestesiologica383769.9Vestnik Khirurgii Imeni I I Grekova1660.4
Pediatric Anesthesia3871718.9International Journal of Scientific Study1650.3
Periodicum Biologorum38300.8Journal of Clinical Monitoring and Computing151067.1
Anaesthesia Pain & Intensive Care36130.4Essentials of Regional Anesthesia1570.5

RC: record count, C: number of citation, AC: average citation per document.

Figure 4. Density map for citation analysis of active journals on regional anesthesia.

6. Active organizations

The top 25 organizations and enhanced organizations producing articles are shown in Table 2.

Table 2 Active organization and organizations-enhanced on regional anesthesia

Harvard University97Harvard University147
University Toronto96University of Toronto129
Stanford University63Assistance Publique Hopitaux Paris Aphp99
Virginia Mason Med Ctr62University of California System98
Duke University51Brigham Women S Hospital84
University Calif San Francisco47University of Helsinki82
University Washington47Mayo Clinic75
Mayo Clinic45Helsinki University Central Hospital74
Brigham Womens Hospital44University Health Network Toronto70
University Helsinki44Virginia Mason Medical Center66
Northwestern University43Stanford University64
Hospital Special Surgery42Cornell University61
Chinese University Hong Kong41University of Munster59
Cornell University39Duke University55
University Pittsburgh38University of Texas System55
University Texas38University of Copenhagen52
University British Columbia36Pennsylvania Commonwealth System of Higher Education Pcshe50
Mcgill University35Ruhr University Bochum49
Wake Forest University32University of California San Francisco47
Tel Aviv University30University of Washington47
University Melbourne30University of Washington Seattle46
University Tsukuba30Universityersity of London45
Yale University30Northwestern University44
Klinikum Minden28University of British Columbia43
Seoul Natl University26Chinese University of Hong Kong42

RC: record count.

7. Active authors

The top 16 authors producing most articles were Rosenberg PH (49), Wulf H (29), Chan VWS (28), Neal JM (28), Horlocker TT (27), Sessler DI (25), Van Aken H (25), Kee WDN (23), Sharrock NE (23), Datta S (22), Hebl JR (22), Khaw KS (22), Nolte H (22), Saito Y (22), Standl T (22), and Tuominen M (22), in descending order.

8. Citation analysis

According to total citation numbers, the top 20 articles receiving most citations from past to present are presented in Table 3. The final column of the table additionally gives the number of citations per year for the article.

Table 3 The 15 most cited manuscripts on regional anesthesia

1Management of postoperative pain: a clinical practice guideline from the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists’ Committee on Regional Anesthesia, Executive Committee, and Administrative CouncilChou et al.Journal of Pain2016699139.8
2Serious complications related to regional anesthesia: results of a prospective survey in FranceAuroy et al.Anesthesiology199764927.04
3Epidural anesthesia and analgesia in high-risk surgical patientsYeager et al.Anesthesiology198763518.68
4Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trialRigg et al.Lancet200259831.47
5Major complications of regional anesthesia in France: the SOS regional anesthesia hotline serviceAuroy et al.Anesthesiology200255929.42
6Cauda equina syndrome after continuous spinal anesthesiaRigler et al.Anesthesia and Analgesia199143414.47
7Effects of epidural anesthesia and analgesia on coagulation and outcome after major vascular surgeryTuman et al.Anesthesia and Analgesia199139813.27
8Neurodevelopmental outcome at 2 years of age after general anaesthesia and awake-regional anaesthesia in infancy (GAS): an international multicentre, randomised controlled trialDavidson et al.Lancet201639478.80
9Epidemiology and morbidity of regional anesthesia in children: a one-year prospective survey of the French-Language Society of Pediatric AnesthesiologistsGiaufré et al.Anesthesia and Analgesia199637515
10Neurological complications after regional anesthesia: contemporary estimates of riskBrull et al.Anesthesia and Analgesia200734624.71
11Does continuous peripheral nerve block provide superior pain control to opioids? A meta-analysisRichman et al.Anesthesia and Analgesia200632921.93
12Tumescent technique for regional anesthesia permits lidocaine doses of 35 mg/kg for liposuctionKleinJournal of Dermatologic Surgery and Oncology199031510.16
13Effects of regional anesthesia on phantom limb pain are mirrored in changes in cortical reorganizationBirbaumer et al.Journal of Neuroscience199730712.79
14Incidence and risk factors for side effects of spinal anesthesiaCarpenter et al.Anesthesiology19922849.79
15Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factorsCaplan et al.Anesthesiology19882828.55
16Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled Veterans Affairs cooperative studyPark et al.Annals of Surgery200127313.65
17Regional anaesthesia and antithrombotic agents: recommendations of the European Society of AnaesthesiologyGogarten et al.European Journal of Anaesthesiology201026123.73
18Ultrasound guidance compared with electrical neurostimulation for peripheral nerve block: a systematic review and meta-analysis of randomized controlled trialsAbrahams et al.British Journal of Anaesthesia200924420.33
19Ultrasound-guided supraclavicular approach for regional anesthesia of the brachial plexusKapral et al.Anesthesia and Analgesia19942198.11
20A quantitative, systematic review of randomized controlled trials of ephedrine versus phenylephrine for the management of hypotension during spinal anesthesia for cesarean deliveryLee et al.Anesthesia and Analgesia200221711.42

PY: publication year, TC: total citation, AC: average citations per year.

9. Co-citation analysis

The reference sections of 6,452 articles cited 69,813 publications. Among these publications there are 8 with more than 100 citations. These publications receiving most citations are, in order, Rodgers et al. (2000) (Number of citations: 168), Auroy et al. (1997) (160), Carpenter et al. (1992) (124), Bromage (1965) (110), Rigler et al. (1991) (110), Moen et al. (2004) (108), Vandermeulen et al. (1994) (105), and Greene (1985) (104) [15-22].

10. Trend topics

In the 6,452 articles, a total of 6,551 different keywords were used. The network map related to the results of cluster analysis of 88 of these keywords, used in at least 20 different articles, is shown in Fig. 5, with the network map, related to trend word analysis, shown in Fig. 6. The most used medication in articles published about the topic of regional anesthesia were bupivacaine (199), dexmedetomidine (108), lidocaine (100), ropivacaine (91), fentanyl (69), levobupivacaine (56), clonidine (51), propofol (41), ketamine (34), and phenylephrine (33) (Table 4).

Table 4 The first trend keywords on regional anesthesia

spinal anesthesia574pain63phenylephrine33complication24
spinal anaesthesia265anaesthetic techniques, subarachnoid60spınal33subarachnoid24
regional anesthesia227surgery58bupıvacaıne32anesthetıc technıques23
epidural anesthesia214pregnancy58spınal anesthesıa32anxiety23
anesthesia214levobupivacaine56anesthesıa, obstetrıc31dexamethasone23
bupivacaine199cesarean delivery54anesthetıc technıques, spınal31hemodynamics23
cesarean section173nerve block53anesthetic techniques31intrathecal23
epidural154peripheral nerve block53ondansetron31obstetric23
spinal152clonidine51anesthesia, epidural30postoperative23
caesarean section137shivering51neuraxial anesthesia30anaesthetic techniques, regional22
hypotension133anesthesia, spinal49local anesthetics29caesarean delivery22
regional anaesthesia131regional49anaesthetic techniques, epidural28postoperative analgesia22
anaesthesia113anaesthesia, obstetric43epıdural anesthesıa28tramadol22
dexmedetomidine108sedation43local anesthesia28bradycardia21
lidocaine100epidural analgesia42epıdural27general21
ropivacaine91propofol41anesthetıc technıques, epıdural26intravenous regional anesthesia21
complications89thoracic epidural anesthesia38children26anaesthetics local, bupivacaine20
epidural anaesthesia89postoperative pain37combined spinal-epidural26blood pressure20
general anesthesia79anaesthetic techniques35midazolam26cardiac output20
analgesia74general anaesthesia34ephedrine25labor analgesia20
fentanyl69ketamine34meta-analysis25total knee arthroplasty20

O: number of occurrences.

Figure 5. Network visualization cluster map for keyword analysis on regional anesthesia.

Figure 6. Network visualization map for trends based on keyword analysis on regional anesthesia.

According to our research findings, a significant increasing trend was found for the number of articles about the topic of regional anesthesia. Initially there were low numbers of articles (a mean of 50 articles per year), with the annual mean rising to 107-215 articles from 1988-2015, before reaching over 300 articles annually from 2015 to the present date. When regression analysis results are assessed, it appears the increasing trend for articles will continue.

When the article distribution by country was investigated, it was observed that developed countries [23] had effective article production (the USA, Germany, the United Kingdom, Canada, Japan, France, Sweden, Australia, Italy, Finland, South Korea, Switzerland, Austria, and the Netherlands). However, developing countries, led by Turkey, such as India, China, and Iran had a notable effect on article productivity. Some bibliometric research in the literature determined that the economic size of a country, or development level, had a significant effect on academic publication productivity [5,13-22,24]. In our study, the significant correlation results found between the number of articles produced by countries and certain development indicators confirm the results of the literature. When the common authorship cooperation of countries is evaluated, clusters like Denmark-Sweden-Finland, or Germany-Switzerland, or Australia-New Zealand show that neighboring geographic region was the most important factor for cooperation.

When the analyzed articles were assessed according to total citation numbers received, the study with the most citations in total was determined to be the study published in the Journal of Pain in 2016 by Chou et al. [25]. After this study, the study with most total citations was the study published in Anesthesiology in 1997 by Auroy et al. [16]. In third place for citations was a study by Yeager et al. (1987) published in Anesthesiology [26]. When evaluated according to annual mean citation numbers, the most effective article was the study by Chou et al. (2016) in the Journal of Pain, with a mean of 111.4 citations [25]. The next most effective study after this was by Davidson et al. (2016) published in the Lancet [27]. According to co-citation analysis findings, all articles commonly cited studies by Rodgers et al. (2000), Auroy et al. (1997), Carpenter et al. (1992), Bromage (1965), Rigler et al. (1991), Moen et al. (2004), Vandermeulen et al. (1994), and Greene (1985) [15-22]. It is recommended that researchers interested in this topic initially read the studies determined by citation and co-citation analyses in this study.

The most active journals producing more than 200 articles were Anesthesia and Analgesia, Acta Anaesthesiologica Scandinavica, Anesthesiology, Regional Anesthesia and Pain Medicine, the British Journal of Anaesthesia, Anaesthesist, and Anaesthesia. Authors wishing to produce articles about this topic may initially pay attention to these journals. When the top 50 journals producing the most articles are assessed according to citation numbers per article, the results according to analysis of the citation network map found the journals Anesthesiology, Obstetrics and Gynecology, Anesthesia and Analgesia, British Journal of Anaesthesia, the American Journal of Obstetrics and Gynecology, and Regional Anesthesia and Pain Medicine received the most citations. Researchers wishing to gain more citations for their articles on this topic may submit to these journals.

When keyword analysis results are assessed, according to trend analysis results in the early years, topics like shivering, anxiety, and caesarean section were followed by dexmedetomidine in order of frequency. In later years, trends in topics studied were determined to be dexamethasone, postoperative analgesia, ketamine, hemodynamics, spinal anesthesia, bupivacaine, and hypotension.

As a result of literature screening, we encountered only 1 study similar to the bibliometric study of our research. Fathi et al. (2015) performed bibliometric research for epidural anesthesia [28]. Firstly, our study is more comprehensive in terms of topic, year interval, and article numbers than this study. The study determined the top 10 authors, organizations, and countries in the distribution of publications about the topic of epidural anesthesia from 1990 to 2013. Our study includes keywords not included in that study, and we also performed citation analysis for journals and articles, and determined international cooperation. Our study is the most comprehensive research analyzing the highest number of articles about this topic.

A limitation of our study is that only the WoS database was used for literature scanning. Databases like PubMed, Google Scholar, and Scopus were not used, because the WoS database indexes articles published in journals with a higher impact factor compared to the other databases [5,24]. Additionally, in situations where more than one database is used for bibliometric studies analyzing large numbers of articles, the inclusion of the same article more than once in the analysis may affect the reliability of the results. Another limitation is; it may be that while using the “peripheral nerve block” as a search word, we did not include variations of this technique for example, brachial plexus block, femoral nerve block, sciatic nerve block, etc.

In conclusion, we presented a summary of 6,452 studies that were in the article category among the studies on regional anesthesia between 1980-2019. This summary will allow an anesthesiologist or other researcher to see the most effective articles, most cited articles, and perhaps the articles that should initially be read in relation to this topic. Observing which journals which produce the most articles in this field, and which journals contain articles receiving most citations, will allow easy assessment of current data. This study may provide an idea about which topics were studied according to year, an investigation of the trending topics, and an identification of new research topics. Additionally, researchers can see the impact level of countries and organizations in relation to this topic. This article will be a beneficial guide for clinicians and scientists about the global output in the field of regional anesthesia.

Selcuk Kayir: Writing/manuscript preparation; Alperen Kisa: Writing/manuscript preparation.

No potential conflict of interest relevant to this article was reported.

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