The publication trends and hot spots of scoliosis research from 2009 to 2018: a 10-year bibliometric analysis.

BACKGROUND: This study aims to quantitatively and qualitatively investigate the trends in scoliosis research and evaluate research hotspots using bibliometric analysis.
METHODS: All relevant publications on scoliosis from the period from 2009 to 2018 were extracted from the Web of Science and PubMed databases. Publication trends were analyzed using an Online analysis platform of literature metrology, Bibliographic Item Co-occurrence Matrix Builder (BICOMB), and CiteSpace software. Hotspots were analyzed and visualized using the gCLUTO software package.
RESULTS: A total of 7,445 scoliosis research publications dated between 2009 and 2018 were found. The spine was the most popular journal in this field during this period. The United States maintained a top position in global scoliosis research throughout the 10 years and has had a pivotal influence, followed by China and Canada. Among all institutions, the University of California, San Francisco, was a leader in research collaboration. At the same time, Professors Yong Qiu and Lawrence G. Lenke made great achievements in scoliosis research. We analyzed the major Medical Subject Headings (MeSH) terms/MeSH subheadings and identified eight hotspots in scoliosis research.
CONCLUSIONS: We summarized the publication information of scoliosis-related literature in the 10 years from 2009 to 2018, including country and institution of origin, authors, and publication journal. We analyzed former research hotspots in the field of scoliosis and predicted future areas of interest. The development of various new orthopedic plants, artificial intelligence diagnosis, and genetic research will be future hotspots in scoliosis research. 2020 Annals of Translational Medicine. All rights reserved.

Introduction

Scoliosis is a three-dimensional (3D) structural spinal deformity and usually manifests as raised ribs, unlevel shoulders, and an asymmetrical waist. It can be diagnosed through a posteroanterior spinal radiograph taken in a standing position which shows a lateral bending of the spine over 10°. In addition to a curved spine, scoliosis is often related to the asymmetry of the trunk and limbs (1). Congenital, neurogenic, and some other classifications of scoliosis have better understood underlying mechanisms compared to idiopathic scoliosis, which denotes a curve of unknown etiology. Idiopathic scoliosis accounts for about 80% of structural coronal deformities (2), and the diagnosis rules out a pre-existing cause. With the continuous improvements in medicine and quality of life, scoliosis has attracted more and more attention. However, many problems relating to clinical treatment and scientific research still need to be solved. According to recent research hotspots combined with practical clinical problems, surgeons and researchers also need to improve the quality of scoliosis diagnosis and treatment, so as to alleviate the pain patients experience during treatment.

In recent years, bibliometric analysis has become increasingly popular. It applies literature metrology characteristics to measure the contribution of an area of research, including disparate countries, institutions, journals, or authors and predicts in detail research trends or hot spots within a certain field. However, there have been few bibliometric studies on scoliosis, and these mainly focus on published information rather than analysis and prediction of research hotspots (3,4). Our previous study showed that biclustering analysis could facilitate the discovery of key research focus areas and related representative literature (5). In particular, co-word biclustering analysis can be used to verify hot spots in research. In this article, we apply an integrated analysis of the content and external features of research literature to identify hot spots in scoliosis pathology, surgical method innovation and implants, quality of life after brace treatment, adverse effects, and diagnostic imaging, as well as genetics. We conduct a brief discussion on scoliosis research and clinical issues and make a prediction on possible progress in the field over the next decade.

Methods

Data sources and search strategies

We considered the Science Citation Index-Expanded and the Social Science Citation Index of Thomson Reuters’ Web of Science to be the most appropriate databases on which to perform our bibliometric analysis. We comprehensively searched Web of Science database to find relevant data from 2009 to 2018 and only included original articles and reviews. The search strategy was presented as follows: TI = (scoliosis) AND Language = English. At the same time, to obtain the Medical Subject Headings (MeSH) terms information which can map the contents of literature and be used to carry out co-word clustering analysis (6), we performed a similar online search on PubMed, which was developed by the National Center for Biotechnology Information (NCBI) of National Library of Medicine (NLM), without language restrictions. The search term used was "scoliosis"[Mesh] from 2009 to 2018. To avoid bias incurred by frequent database renewal, all literature retrieval and data downloads were completed in a single day, September 26, 2019.

Data collection

Two reviewers (Z Tao and S Zhou) independently performed the primary search, and their agreement rate reached 0.90, showing significant accordance (7). Web of Science Core Collection (WoSCC) data including titles, countries of origin, institutions, journals, and authors, were extracted and imported into the Online Analysis Platform of Bibliometrics (http://bibliometric.com/) and CiteSpace V5.5.R1 SE, 64bit (Drexel University, Philadelphia, PA, USA) for bibliometric analysis. PubMed data were imported into the BICOMB (Bibliographic Item Co-Occurrence Matrix Builder) (8) for further hot spot analysis.

Bibliometric analysis

We attempted to describe all publication characteristics, including countries, institutions, journals, authors, and H index. We accessed the 2018 version of Journal Citation Reports (JCR) to obtain the impact factor (IF), which is regarded as an important indicator to measure the scientific value of research (9). In our study, we analyzed the annual publication numbers and growth tendencies of different countries/regions through the Literature Metrology online analysis platform. CiteSpace is an optimal means for collaboration network analysis to connect all kinds of publication characteristics. It can also obtain keywords with high citations to predict the research frontiers and emerging trends in this area. Through CiteSpace, a “time slicing” function can also be applied (e.g., if you set the “years per slice” to 1 while the “top N per slice” is set to 50, the top 50 papers in a year are exported into a single file). According to our objective, nodes of different sizes represented citation counts or publication counts (10,11).

Co-word biclustering analysis of research hotspots

Biclustering was used to display the connection between extremely frequent terms and source literature, and the connection among extremely frequent terms. To survey the hotspots of scoliosis study, we performed a biclustering analysis of the incorporated publications and major MeSH terms/MeSH subheadings. BICOMB is a binary matrix that has source literature as columns and major MeSH terms/MeSH subheadings as rows, and structured through software “gCLUTO” version 1.0 (12). The detailed principle is explained in our previous research (5). We found semantic relationships between major MeSH terms/MeSH subheadings and source literature in clusters of scoliosis research focus and mapped them by matrix and mountain visualization.

Results

The output of related literature

A total of 7,445 publications (6,866 articles and 579 reviews) from 2009 to 2018 met our inclusion criteria (). shows the increasing trend in the numbers of scoliosis-related publications (from 481 in 2009 to 966 in 2018).

Figure 1

Flow chart of literature filtering included in this study. WoSCC, Web of Science Core Collection.

Figure 2

Output of related literature. The number of annual publications (A) and growth trends of the top 10 countries/regions (B) in scoliosis research from 2009 to 2018.

The contributions of countries and institutions to global publications

The incorporated literature on scoliosis was contributed by at least 84 different countries or regions (). The United States [2,818] was the largest contributor to scoliosis research, followed by China [1,281], Canada [561], Japan [529], and France [444]. Centrality is a major indicators to determine the importance of nodes in the network and a higher centrality means that the node is more important in this network, so the results showed that the United States had more impact than any other country (centrality =0.22), and then England (0.16), and Germany (0.14) (). In terms of research institutions, the top 10 included the University of California, San Francisco [347], Nanjing University [301], Washington University [297], Chinese University of Hong Kong [263], and New York University [234] (). A low-density map of the scoliosis research network (density =0.0642) () means that the research teams were relatively scattered across various institutions, and more mutual cooperation is needed. Most of the central indexes are below 0.15, indicating that most institutions had a low level of impact and that there was insufficient cooperation during the 10-year period. International cooperation analysis showed that cooperation happened most frequently between the United States and Canada, followed by the United States and China ().

Table 1

The top 10 countries/regions and institutions contributing to publications in scoliosis research

Rank	Country/region	Article counts	Centrality	Institutions	Article counts	Centrality	Total number of citations	Average number of citations	Total number of first authors	Total number of first author citations	Average number of first author citations
1	US	2,818	0.22	Univ Calif San Francisco	347	0.12	3,977	11.46	70	446	6.37
2	China	1,281	0.02	Nanjing Univ	301	0.02	1,650	5.48	186	713	3.83
3	Canada	561	0.08	Washington Univ	297	0.16	3,643	12.27	90	1,324	14.71
4	Japan	529	0.02	Chinese Univ Hong Kong	263	0.13	1,819	6.92	41	344	8.39
5	France	444	0.04	NYU	234	0.05	2,795	11.94	96	1,467	15.28
6	England	376	0.16	Hosp Special Surg	222	0.08	2,169	9.77	55	369	6.71
7	South Korea	338	0	Univ Virginia	203	0.11	3,183	15.68	56	1,234	22.04
8	Italy	296	0.05	Johns Hopkins Univ	197	0.04	897	4.55	73	352	4.82
9	Turkey	294	0.04	Shriners Hosp Children	183	0.14	1,748	9.55	71	652	9.18
10	Germany	288	0.14	Univ Montreal	173	0.01	1,107	6.40	24	118	4.92

Figure 3

The distribution of countries/regions and institutions. The network map of institutions involved in scoliosis research (A) and cooperation between countries/regions (B).

Journals publishing researches on scoliosis

Recently, 1,056 journals have appeared in the field of scoliosis research. The top 10 most popular journals published 3,308 of all 7,445 pieces of literature on scoliosis in our study (44.43%) (). Of these, the top 3 journals are Spine, European Spine Journal, and Spine Journal, which accounted for more than 30.50% of all the indexed publications. The highest IF belonged to The Journal of Bone and Joint Surgery-American Volume (4.716), followed by Spine Journal (3.196), Journal of Neurosurgery-Spine (2.998), Spine (2.903), and European Spine Journal (2.513). According to the JCR 2018 standards, the five journals mentioned above are classified as Q1, the Journal of Pediatric Orthopaedics, World Neurosurgery, and Clinical Spine Surgery are classified as Q2, and the American Journal of Medical Genetics Part A is classified as Q3.

Table 2

The top 10 most active journals that published articles in scoliosis research (sorted by count)

Rank	Journal title	Percentage (N/7,445)	IF (2018)	Quartile in category (2018)	H-index	Article counts	Total number of citations	Average number of citations
1	Spine	15.92%	2.903	Q1	228	1,185	11,968	10.1
2	European Spine Journal	10.44%	2.513	Q1	117	777	4,623	5.95
3	Spine Journal	4.15%	3.196	Q1	94	309	1,123	3.63
4	Journal of Pediatric Orthopaedics	3.79%	2.046	Q2	84	282	1,404	4.98
5	Journal of Neurosurgery-Spine	2.81%	2.998	Q1	84	209	1,305	6.24
6	Journal of Spinal Disorders & Techniques	1.84%	0	0	85	137	805	5.88
7	Journal of Bone and Joint Surgery-American Volume	1.48%	4.716	Q1	235	110	872	7.93
8	World Neurosurgery	1.38%	1.723	Q2	85	103	39	0.38
9	Clinical Spine Surgery	1.37%	1.726	Q2	12	102	105	1.03
10	American Journal of Medical Genetics Part A	1.26%	2.197	Q3	79	94	120	1.28

The contributions of authors to scoliosis research

The ten authors who published the most papers out of all 22,511 authors in this study are listed in . Of these, Yong Qiu, from the Department of Spine Surgery, Nanjing Drum Tower Hospital in China, ranked first [221], and second was Virginie Lafage from the Department of Orthopaedic Surgery, Hospital for Special Surgery in the USA [178]. These two scholars made great achievements and have become authorities in scoliosis research. We analyzed the citation information for authors () and co-cited authors (), visualizing them in a network by CiteSpace. Lawrence G. Lenke (899 co-citations) ranked first in the top 10 co-cited authors, followed by Young-Jo Kim [786], Keith H. Bridwell [661], and Si Suk [647] (). The centrality of the top 4 is more than 0.1, demonstrating that they have become an influential core group in the scoliosis field, having carried out a lot of research to lay a better foundation for future development. And the analysis of high-cited papers showed Virginie Lafage group have an amazing scientific impact for other scholars, 4 of top 10 high-cited papers were published by this group ().

Table 3

The top 10 most productive authors and co-cited authors contributed to publications in scoliosis research

Rank	Author	Article counts	Centrality	Total number of citations	Average number of citations	First author counts	First author citation counts	Average first author citation counts	Corresponding author	Corresponding author citation counts	Co-cited author	Citation counts	Centrality
1	Qiu Y	221	0.04	1,086	4.91	5	63	12.60	101	582	Lenke LG	899	0.22
2	Lafage V	178	0.04	2,424	13.62	5	329	65.80	33	1,108	Kim YJ	786	0.24
3	Zhu ZZ	172	0.09	644	3.74	8	48	6.00	49	99	Bridwell KH	661	0.23
4	Smith JS	150	0.08	2,169	14.46	22	802	36.45	32	529	Suk Si	647	0.10
5	Shaffrey CI	144	0.10	2,255	15.66	0	0	0	15	670	Weinstein SL	636	0.07
6	Lenke LG	129	0.39	1,927	14.94	5	215	43.00	36	681	Glassman SD	623	0.06
7	Bess S	128	0.02	1,437	11.23	7	255	36.43	8	265	Schwab F	545	0.07
8	Ames CP	118	0.04	1,386	11.75	2	42	21.00	12	106	Lonstein JE	489	0.08
9	Schwab F	118	0.09	2,236	18.95	4	489	122.25	2	161	Kuklo TR	429	0.05
10	Liu Z	109	0.14	435	3.99	7	54	7.71	2	0	Smith JS	422	0.04

Figure 4

The distribution of authors engaged in scoliosis research. The network map of productive authors (A) and the network map of co-cited authors (B).

Table 4

The top 10 high-cited papers in scoliosis research during 2009 to 2018

Rank	Title	Journal	Corresponding authors	Publication year	Total citations
1	Prader-Willi syndrome	Genetics in Medicine	Cassidy SB	2012	465
2	Pelvic tilt and truncal inclination: two key radiographic parameters in the setting of adults with spinal deformity	Spine	Lafage V	2009	458
3	Adult spinal deformity-postoperative standing imbalance: how much can you tolerate? An overview of key parameters in assessing alignment and planning corrective surgery	Spine	Lafage V	2010	373
4	Scoliosis Research Society-Schwab Adult Spinal Deformity Classification: a validation study	Spine	Lafage V	2012	334
5	Effects of bracing in adolescents with idiopathic scoliosis	New England Journal of Medicine	Weinstein SL	2013	310
6	Friedreich ataxia: the clinical picture	Journal of Neurology	Pandolfo M	2009	275
7	Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis	Spine	Lafage V	2013	269
8	Accuracy of pedicle screw placement: a systematic review of prospective in vivo studies comparing free hand, fluoroscopy guidance and navigation techniques	European Spine Journal	Gelalis ID	2012	226
9	Complications of growing-rod treatment for early-onset scoliosis: analysis of one hundred and forty patients	Journal of Bone and Joint Surgery-American Volume	Akbarnia B	2010	210
10	Postural deformities in Parkinson’s disease	Lancet Neurology	Bloem BR	2011	208

Analysis of the scoliosis hotspots

Based on the search results, there were 4,857 major MeSH terms/MeSH subheadings with a cumulative frequency of 24,055 times. They can be defined as extremely frequent terms that appeared more than 52 times after a standard evaluation of H-index, and their frequency accounted for 46.78% (11,252/24,055) of all (). We analyzed the temporal trend of hotspot shift according to the top 25 terms with the strongest citation bursts during 2009 to 2018 (). And we sorted eight different clusters by biclustering, mapping the connection between source literature and MeSH terms/MeSH subheadings by mountain and matrix visualization (). The biclustering result can visually show the substance of high-dimensional datasets through mountain visualization. There are 8 perks representing 8 clusters in the 3D landform numbered from 0 to 7 (). The information of these clusters is reflected by the perks’ volume, altitude, color and location on the flat. The flat location can distinguish different perks and their interval represents their relative similarity of each cluster. The altitude and color of the perks are usually proportional to the internal similarity and standard deviation of the cluster (blue: high deviation; red: low deviation). The volume of peaks directly reflects the number of extremely frequent major MeSH terms/MeSH subheadings in each cluster. In addition, every cluster should contain at least 30 publications and no triplet perks are allowed to emerge in mountain visualization. In matrix visualization, the column tags and row tags represent PMIDs of source literature and MeSH terms/MeSH subheadings, respectively. The matrix values are represented graphically and their colors paint the emergence frequency of the major MeSH terms/MeSH subheadings in a piece of literature. The color turns from white to red to show a gradual increase in significance (). To make analogous rows in a single converged cluster, we reset the rows of the initial matrix and used black horizontal lines to partition each cluster through gCLUTO (). In matrix visualization, the upper cluster tree represented the literature association and the left cluster tree represented extremely frequent MeSH terms/subheadings association (). The above-mentioned 52 extremely frequent terms were divided into 8 clusters and all representative source literature involved in each cluster was studied to summarize the hotspot information further. We finally generalized them into the following 8 hotspots:

Table 5

Highly frequent major MeSH terms from the included publications on scoliosis (n=24,055)

Rank	Major MeSH terms/MeSH subheadings	Frequency	Proportion of frequency (%)	Cumulative percentage (%)
1	Scoliosis/surgery	2,550	10.6007	10.6007
2	Spinal fusion/methods	742	3.0846	13.6853
3	Scoliosis/diagnostic imaging	733	3.0472	16.7325
4	Thoracic vertebrae/surgery	464	1.9289	18.6614
5	Lumbar vertebrae/surgery	372	1.5465	20.2079
6	Scoliosis/therapy	358	1.4883	21.6961
7	Scoliosis/physiopathology	356	1.4799	23.1761
8	Scoliosis/diagnosis	352	1.4633	24.6394
9	Spinal fusion/adverse effects	321	1.3344	25.9738
10	Spinal fusion/instrumentation	296	1.2305	27.2043
11	Kyphosis/surgery	273	1.1349	28.3392
12	Spine/surgery	270	1.1224	29.4617
13	Scoliosis/complications	253	1.0518	30.5134
14	Scoliosis/genetics	243	1.0102	31.5236
15	Scoliosis/pathology	240	0.9977	32.5213
16	Scoliosis/epidemiology	210	0.8730	33.3943
17	Spine/diagnostic imaging	200	0.8314	34.2257
18	Spinal fusion	190	0.7899	35.0156
19	Braces	185	0.7691	35.7847
20	Scoliosis/etiology	179	0.7441	36.5288
21	Thoracic vertebrae/diagnostic imaging	141	0.5862	37.1149
22	Bone screws	139	0.5778	37.6928
23	Orthopedic procedures/methods	139	0.5778	38.2706
24	Lumbar vertebrae/diagnostic imaging	119	0.4947	38.7653
25	Quality of Life	119	0.4947	39.2600
26	Scoliosis/rehabilitation	116	0.4822	39.7423
27	Scoliosis/psychology	115	0.4781	40.2203
28	Osteotomy/methods	110	0.4573	40.6776
29	Scoliosis	109	0.4531	41.1307
30	Orthopedic procedures/instrumentation	105	0.4365	41.5672
31	Pedicle Screws	99	0.4116	41.9788
32	Postoperative complications/epidemiology	97	0.4032	42.3820
33	Postoperative complications/etiology	93	0.3866	42.7687
34	Imaging, three-dimensional/methods	80	0.3326	43.1012
35	Internal fixators	80	0.3326	43.4338
36	Spine/abnormalities	80	0.3326	43.7664
37	Spine/pathology	74	0.3076	44.0740
38	Tomography, X-ray computed/methods	66	0.2744	44.3484
39	Orthopedic procedures/adverse effects	64	0.2661	44.6144
40	Ribs/surgery	64	0.2661	44.8805
41	Prostheses and Implants	62	0.2577	45.1382
42	Kyphosis/diagnostic imaging	60	0.2494	45.3877
43	Postural balance/physiology	59	0.2453	45.6329
44	Posture	59	0.2453	45.8782
45	Scoliosis/congenital	56	0.2328	46.1110
46	Cerebral palsy/complications	54	0.2245	46.3355
47	Scoliosis/classification	54	0.2245	46.5600
48	Genetic predisposition to disease	52	0.2162	46.7761

MeSH, Medical Subject Headings.

Figure 5

The top 25 terms with the strongest citation bursts during 2009 to 2018.

Figure 6

Mountain visualization of biclustering of highly frequent major MeSH terms and literatures on scoliosis. MeSH, Medical Subject Headings.

Figure 7

Visualized matrix of biclustering of highly frequent major MeSH terms and PubMed Unique Identifiers (PMIDs) of literatures on scoliosis. MeSH, Medical Subject Headings.

Table 6

Highly frequent major MeSH a terms-source literatures matrix (localized)

No.	Major MeSH terms/MeSH subheadings	PubMed Unique Identifiers of source articles
		18188567	18357448	18389266	...	30691740
1	Scoliosis/surgery	1	1	1	...	0
2	Spinal fusion/methods	1	0	0	...	0
3	Scoliosis/diagnostic imaging	0	0	0	...	1
4	Thoracic vertebrae/surgery	1	1	0	...	0
...	...	...	...	...	...	...
47	Scoliosis/classification	0	0	0	...	0
48	Genetic predisposition to disease	0	0	0	...	0

MeSH, Medical Subject Headings.

Quality of life and levels of psychological stress in patients with adolescent idiopathic scoliosis (AIS) treated with braces (Cluster 0);

Pathology of scoliosis (Cluster 1);

Innovative instrumentation and methods used in the surgery of scoliosis (Cluster 2);

Adverse effects of scoliosis (Cluster 3);

Diagnostic imaging of scoliosis (Cluster 4);

Prostheses and implants of scoliosis (Cluster 5);

Genetics researches of scoliosis (Cluster 6);

Asymmetrical postures in cerebral palsy (CP) resulting in scoliosis (Cluster 7).

Discussion

Our statistical and quantitative analysis found that the research output on scoliosis gradually increased in the 10 years from 2009 to 2018, and more and more scholars are focusing their research in the field. Although the research has been extensive, it is relatively messy, and there is a lack of analysis of research hotspots. In this work, we focused on the discussion and interpretation of the eight clusters obtained by co-word biclustering analysis to predict and direct future research trends.

Cluster 0 relates to the quality of life and levels of psychological stress in patients with AIS treated with braces. AIS has been the most common form of spinal deformity in adolescents. Patients with curves between 20° and 40° cobb degrees do not need to undergo surgery, and conservative treatment may be a better choice. Although there are several conservative treatment options, only bracing has been proved to be effective in increasing the spine balance rate and in reducing hump amplitude to prevent the progression of AIS and subsequent surgical needs further. The brace treatment has become the first choice for clinical use of such patients, and the modified “P” Cheneau brace has become a remarkable success as a conservative treatment for AIS on the basis of the SRS/SOSORT criteria (13,14). In addition, related quality of life assessments has drawn great attention from orthopedists all over the world. Recent research found that all teenagers may have some psychological stress in the early stages of wearing a brace, but as they adapt to their new image, this pressure may not impact their long-term quality of life (15,16). Considering early psychological stress, we believe research in this field will provide an important reference for the improvement of the brace as a treatment in the future, and that it may maintain its popularity as an area for future study.

Cluster 1 relates to the pathology of scoliosis, which includes the pathological changes caused by spine deformity and vertebral body rotation, as well as updates on the rapid diagnostic method of imaging. Morphological characteristics and pathological changes to the spine have a great impact on idiopathic scoliosis clinical treatment. Doctors tried their best to detect and reconstruct the actual situation of the patient based on the imaging examination, which can accurately assess pathologies such as spine alignment and dyskinesia. Novel computational methods to evaluate vertebral segmental movement and multiple detection methods have been established, such as a multichannel transmit/receive phased array RF coil which can be used for in vivo spine imaging, thereby rendering high-resolution spine imaging a promising new application in IS clinical research (17-19). More and more valuable literature will appear in the near future focused on this topic.

Cluster 2 relates to the innovative instrumentation and methods used in scoliosis surgery. In recent years, with the rapid development of medical technology, doctors and patients are increasingly pursuing surgical treatments. At the same time, the focus of medical research in the new era has gradually shifted from basic research to translational research. For patients to achieve the best recovery with minimal harm, doctors and scientists have improved a variety of surgical methods and invented more convenient types of surgical equipment based on their years of experience and research (19-22). In this era of innovation and cooperation, medical-industrial integration and clinical translation medicine will surely become the most popular area for development in the future and maybe the most popular research topic in the next decade.

Cluster 3 relates to the adverse effects of scoliosis. Orthopedic surgery for spinal deformity is a difficult and high-risk surgical method in the orthopedic field. Postoperative complications often occur, especially nerve damage. With the application of new surgical methods for spinal deformity; however, more attention has been paid to the related complications of different surgical procedures (23-26). Although, with the continuous development of surgeons’ abilities and modern medical technology, the incidence of complications of surgery for spinal deformity is declining. Therefore, the number of studies in this area may gradually decrease in the future, and more attention will perhaps be paid to some rare complications in the form of case reports.

Cluster 4 relates to the diagnostic imaging of scoliosis. Scoliosis is usually detected during a standard physical examination performed by a general practitioner or school nurse. Cobb Angle plays an important role in idiopathic scoliosis as a main diagnostic index. However, although measurements have been established, Cobb Angle measures a two-dimensional (2D) projection that is actually a 3D distortion, so using Cobb Angle alone is not a reliable way of assessing the deformity. Based on the fact that the etiology of 3D malformations and idiopathic scoliosis is unknown, recent studies have shown interest in obtaining additional measures to describe and quantify scoliosis (27-30). The establishment of these methods can help improve the accuracy of scoliosis diagnosis, help surgeons to understand the patient’s deformity better and guide further treatment. With the continuous development of augmented reality (AR), virtual reality (VR), and mixed reality (MR) technology, more detailed imaging methods will appear, and there will be a definite and significant increase in this type of research.

Cluster 5 relates to prostheses and implants for scoliosis. Surgical treatment of scoliosis in older children is more straightforward and includes correction of spinal curvature, internal fixation, and spinal fusion. However, spinal fusion may not be the best option for young children with significant growth potential because it limits further longitudinal growth of the spine, thereby limiting the growth of the thoracic cavity and potentially inhibiting lung development, leading to respiratory dysfunction and, in some cases, premature death. To address these issues, “non-fusion” technologies have recently been implemented with varying degrees of success, and are attracting increasing levels of attention. Various techniques have been used, such as dual growing rods, Shilla procedure, VEPTR (Vertical Prosthetic Titanium Prosthetic Rib), vertebral stapling, and vertebral tethering, each with advantages and disadvantages (31-34). The emergence of new implants and surgical techniques has seen improved treatments for patients with different conditions that meet the requirements of modern precision medicine. There is reason to believe that research in this area has bright prospects.

Cluster 6 relates to the genetics researches of scoliosis. In recent years, some studies have suggested that genetic factors play an important role in the pathogenesis of scoliosis. They also show a high degree of genetic heterogeneity in autosomal dominant or multifactorial inheritance patterns with major genes. Many studies identified idiopathic scoliosis-susceptible genes (such as SH3GL1, GADD45B, and FGF22) and linked them to idiopathic scoliosis, but these genes are not relevant to all idiopathic scoliosis cases (35-38). There is no doubt that idiopathic scoliosis is a hereditary disease, so finding its related pathogenic genes is of great significance for the prevention or treatment of idiopathic scoliosis, and it must be a hot spot for future research.

Cluster 7 relates to asymmetrical postures in cerebral palsy resulting in scoliosis. Cerebral palsy is an immature, non-progressive lesion that causes movement and postural disorders in the brain. Although cerebral palsy is a static encephalopathy, the related musculoskeletal pathology is usually progressive. Many patients with cerebral palsy, especially those with spastic hemiplegia, have asymmetrical frontal spine (39). Many studies have shown that postural asymmetry is associated with scoliosis, dislocation of the hip, contracture of the hip and knee joint, and the inability to change position (40,41). Therefore, postural problems play an important role in preventing cerebral palsy in children with motor dysfunction. The discussion surrounding this topic has been very lively in the past decade, but because of its limited perspective, it is difficult to predict whether its popularity will continue in future research.

Nonetheless, there may have been some limitations to our study. The databases update continuously, and we only selected the literature published from 2009 to 2018, excluding those published in 2019. Therefore, a discrepancy may exist between our bibliometric analysis and real publication conditions. In addition, the amount of scoliosis-related literature may increase rapidly with the breakthrough of future research.

Conclusions

We summarized the publication information of scoliosis-related literature in the 10 years from 2009 to 2018, including country and institution of origin, authors, and publication journal. We then analyzed the research hotspots based on these publications and predicted future popular trends. Effective treatment of idiopathic scoliosis patients and improvements in quality of life will become the focus of scoliosis research, containing many aspects. Many previous studies have focused on the classification of scoliosis and the choice of corresponding treatment methods. Bracing and surgical treatment will help patients at different stages. In addition, the emergence of new surgical methods, new equipment and new implants using cutting-edge technology, the invention of more accurate image examination and diagnostic technology, and evaluation of postoperative complications management and quality of life all contribute to improving patient outcomes. Finally, research on the etiology of scoliosis, especially genetic research, has great potential to guide the prevention and treatment of scoliosis in the future. We believe our research can reflect novel directions for scoliosis research, and the hotspots mentioned will achieve major scientific breakthroughs someday.