Global research trends in spinal ultrasound: a systematic bibliometric analysis

Abstract

Background: In recent years, there has been increased interest in the use of ultrasound technology in the evaluation of spinal and paraspinal regions.

Objective: This study aimed to investigate trends in spinal ultrasound research from 1994 to 2015 and compare the contributions of such research from different countries and authors.

Study design: Bibliometric analysis.

Setting: Publications related to spinal ultrasound from 1994 to 2015 were retrieved from the Web of Science database.

Methods: Excel 2013, GraphPad Prism 5, and VOSviewer were used to summarise bibliometric features, including the number of publications, citation frequency, H-index, and country contributions and hotspots (keywords of popular scientific fields).

Results: A total of 3859 papers were included. The global inflection point (the point in time when the publication growth rate moved from positive to negative) came in 2010. The United States contributed the largest percentage of articles (1041; 26.9%), with the most citations (19 848) and the highest H-index (61). The journals Osteoporosis International and Spine had the highest publication number. The University of Toronto and the University of California, San Francisco were the most contributive institutions. Studies could be divided into three clusters: surgery, osteoporosis, and others. The keywords 'adolescent idiopathic scoliosis' and 'anaesthesia' were the latest hotspots, appearing around 2012.

Conclusion: Spinal ultrasound literature has grown continuously over the last 22 years, with the rate slowing down after 2010. The United States was the largest contributor in this field. Recent studies on topics related to 'adolescent idiopathic scoliosis' and 'anaesthesia' were relatively new and should be closely followed in spinal ultrasound research.

Keywords: adolescent idiopathic scoliosis; anaesthesia; bibliometric; spine; ultrasound.

Figure 1

Global trends in research on spinal ultrasound (US) applications. (A) The number of worldwide publications on spinal US applications and the line of the sum of research-related article fractions (percentage of research from all regions). (B) Model fitting curves of growth trends in worldwide publications on spinal US applications.

Figure 2

(A) The sum number, citation frequency and H-index data of publications on spinal ultrasound (US) applications from the top 10 contributing institutions. (B) The number of studies funded by the top 10 funding institutions. (C) The number of publications in the top 10 journals on spinal US applications. (D) The number of publications in the top 10 popular fields of research on spinal US applications.

Figure 3

(A) Mapping of keywords in the research on spinal ultrasound (US) applications; the size of the points represents the frequency, and the keywords are divided into three clusters: surgery (left corner in red), osteoporosis (right corner in green), and others (middle corner in blue). (B) Distribution of keywords according to the mean frequency of appearance; keywords in blue appeared earlier than those in yellow.

Figure 4

Mapping of co-cited references related to spinal ultrasound (US) application. (Note: given the large number of cited references, this study only selected papers cited more than 10 times for analysis. Ultimately, 680 papers were included in the analysis. The 680 points with different colours represent the 680 cited papers. A line between two points means that both were cited in one paper. A shorter line indicates a closer link between two papers. Points in the same colour belong to the same cluster among the four total clusters: clusters one and two (green and red) are papers related to osteoporosis; cluster three (yellow) contains papers related to surgery; and cluster four (blue) contains papers related to anaesthesia.)