Collaboration and Innovation: A Bibliometric Study of the Rise in MMA Embolization in Neurosurgery

Abstract

Chronic subdural hematoma (cSDH) is a common neurosurgical condition in the elderly, often resulting from minor head trauma. Traditional surgical treatments such as burr-hole drainage carry recurrence rates of 10–20% and significant risks in older patients, especially those on anticoagulation therapy. Middle meningeal artery (MMA) embolization has emerged as a minimally invasive alternative, aiming to reduce blood flow to the dura and thereby promote hematoma resolution and lower recurrence. We conducted a bibliometric analysis of publications on MMA embolization for cSDH up to December 2023. The analysis shows a sharp increase in research activity over the past decade. North America, Japan, and Europe are leading contributors, with collaborative networks forming among major institutions. Key journals in neurosurgery and neurointervention have published much of this research, and author collaborations are extensive. Frequently used keywords such as “recurrence” and “treatment outcome” reflect an emphasis on reducing rebleeding and improving patient outcomes. In conclusion, MMA embolization is rapidly gaining attention as a promising treatment for cSDH. While early results are favorable and multi-center efforts are expanding the evidence base, further research is needed to establish long-term efficacy, optimize patient selection, and standardize techniques.

1. Introduction

1.1. Background

Chronic subdural hematoma (cSDH) is one of the most frequently encountered neurosurgical conditions, primarily affecting elderly patients. This condition involves the accumulation of blood between the dura mater and arachnoid membrane, often resulting from minor head trauma [1]. Traditional management approaches, such as burr hole evacuation and craniotomy, while effective, are associated with recurrence rates as high as 10–20%, posing ongoing risks for patients. In older adults and those on anticoagulation therapy, surgical interventions also carry significant morbidity risks, creating a clinical need for safer, less invasive treatment alternatives [2].

Embolization, particularly targeting the middle meningeal artery (MMA), has emerged as a potential solution to address these challenges. This technique involves selectively occluding the MMA to reduce blood flow to the dura mater, thereby promoting hematoma resorption and reducing the likelihood of recurrence. MMA embolization offers a minimally invasive approach, especially appealing for patients at high surgical risk, and early evidence suggests favorable outcomes with lower recurrence rates [1,2,3,4,5].

Despite its potential, the literature on MMA embolization for cSDH is still relatively scarce. A systematic review of research in this area is essential to understand its trajectory and clinical relevance. This bibliometric analysis provides an overview of the research landscape, identifying key contributors, prominent themes, and collaborative networks. By examining the growth of publications and collaboration patterns, this study aims to offer insights into the emerging role of embolization in cSDH treatment.

1.2. Objectives

This study aims to:

• Assess the trend in publications on embolization for cSDH over the past decade, positioning it as an emerging field.
• Identify leading journals, authors, institutions, and geographic contributors advancing embolization research.
• Examine collaborative networks and thematic focuses within the literature, highlighting areas for future research.
• Outline current evidence gaps and provide recommendations for further study to establish MMA embolization as a validated treatment option for cSDH.

2. Materials and Methods

2.1. Data Source and Search Strategy

A bibliometric analysis was conducted using PubMed to capture articles published through December 2023. The PubMed database was chosen for its high recognition and established credibility in assessing journal impact and citation metrics.

The search terms used were:

• “chronic subdural hematoma” OR “cSDH” AND
• “embolization” OR “endovascular treatment” AND
• “middle meningeal artery” OR “MMA”

Boolean operators ensured comprehensive coverage, with no restrictions on study type, thus including case reports, observational studies, systematic reviews, and meta-analyses. The bibliometric approach allowed for systematic data extraction and analysis of publication frequency, key contributors, collaborative networks, and thematic patterns. No explicit language restrictions were applied; however, the search was conducted using English terms, so the results predominantly included English-language publications.

2.2. Inclusion and Exclusion Criteria

• Inclusion: Articles discussing embolization techniques for managing cSDH, including case series, observational studies, reviews, and systematic analyses.
• Exclusion: Editorials and non-peer-reviewed articles were excluded to maintain focus on clinically relevant studies with reproducible findings.

2.3. Data Extraction and Bibliometric Indicators

For each selected article, bibliometric indicators such as publication year, title, authors, journal, keywords, citation counts, and geographic origin were extracted. Institutional affiliations were used to analyze collaboration networks and geographic contributions to the research landscape.

2.4. Data Analysis

Data were analyzed to identify publication trends, author networks, journal impact, and key research themes. Visualization tools included an area plot for publication trends, a table of top journals, and bar charts for author contributions and keyword frequency, providing a comprehensive view of the emerging role of embolization for cSDH. This analysis was performed with Bibliometrix software [6], where a detailed analysis was performed. The results were presented in tables and figures.

3. Results

3.1. Publication Trends

The area plot in Figure 1 shows a marked increase in publications on embolization for cSDH over the last decade, signaling its emergence as a promising treatment modality. Notably, case reports have contributed significantly to this growth, reflecting initial clinical explorations and shared experiences across varied patient demographics. This increasing publication volume supports MMA embolization’s position as an innovative approach for managing cSDH, especially in high-risk patient groups.

3.2. Geographic Distribution and Institutional Contributions

Geographic analysis reveals significant contributions from North America, Japan, and European countries (Figure 2), with leading institutions such as Johns Hopkins University, Baylor College of Medicine, and the University of Tokyo. These centers are recognized for their advanced facilities in neurosurgery and interventional radiology, positioning them at the forefront of embolization research. Collaborative networks among these institutions indicate shared efforts in procedural standardization and outcome analysis.

3.3. Top Journals

Figure 3 provides an overview of the top 10 journals publishing on embolization in cSDH. Notably, journals such as the World Neurosurgery, Journal of Neurointerventional Surgery and Neurosurgery serve as primary platforms, emphasizing the technical nature of this research field and its importance within specialized neurosurgical and radiological literature.

3.4. Author Networks and Collaboration Patterns

A network analysis in Figure 4 presents the top authors contributing to embolization research for cSDH. These authors, affiliated with leading institutions, demonstrate a high level of collaboration, as multi-center studies and co-authored works across specialties increase. This networked approach allows for more robust clinical data, with findings reinforced by contributions from neurosurgeons, radiologists, and interventional specialists.

3.5. Keyword Analysis and Research Themes

The bar chart in Figure 5 highlights frequently used keywords, with terms such as “treatment outcome,” “recurrence,” and “angiography” pointing to a strong focus on the clinical efficacy and safety of embolization. The prominence of “recurrence” as a keyword aligns with cSDH management challenges, as researchers seek to establish embolization as a durable solution to prevent re-bleeding and minimize repeat procedures.

4. Discussion

4.1. Summary of Findings

This expanded analysis demonstrates that MMA embolization for cSDH is gaining substantial research interest, particularly within specialized institutions and collaborative networks. The increase in publications, including case reports, underscores the interest in testing embolization in varied patient contexts [1,2,3,4,5,7,8,9,10,11].

4.2. Interpretation of Trends and Contributions

The geographic distribution, with a high concentration of research from North America, Japan, and Europe, indicates that embolization is being explored in regions with advanced healthcare infrastructure. These institutions, often collaborating across specialties, serve as hubs for pioneering embolization techniques.

4.3. Clinical and Research Implications

With recurrence rates as a major issue in cSDH management, the focus on keywords like “recurrence” and “treatment outcome” reflects the primary clinical goal of embolization. Collaborative networks enable a multi-center approach, which strengthens the evidence base. From a clinical perspective, recognizing the emerging research trends and key themes identified in this bibliometric analysis (for example, the emphasis on reducing recurrence) can provide clinicians with greater confidence in considering MMA embolization as a viable treatment option for appropriate cSDH patients. For researchers, insights into the collaboration networks and prolific topics highlight which unanswered clinical questions—such as long-term efficacy, optimal patient selection criteria, and standardization of techniques—should be prioritized in future studies. In this way, the bibliometric findings help bridge the gap between research and practice by identifying where evidence is accumulating and guiding stakeholders toward areas most in need of further investigation [12].

4.4. Research Gaps and Future Directions

Despite the growth in research, there remain gaps in long-term data, standardized procedural guidelines, and patient selection criteria. Further research should aim to evaluate quality-of-life outcomes, cost-effectiveness, and variations in embolic material and techniques [13]. Furthermore, ongoing randomized controlled trials—such as the currently underway MAGIC-MT trial in China [5]—are expected to provide high-level evidence regarding the efficacy and safety of MMA embolization. The results of these trials will likely influence future research directions and clinical adoption of the procedure, either by validating MMA embolization as a standard adjunct treatment for cSDH or by clarifying its limitations and optimal use cases.

4.5. Limitations

This study is limited by potential gaps in data due to database restrictions and language limitations, which may omit relevant studies published outside of the main bibliometric sources. Notably, although we did not impose a language filter, our English-based search strategy likely underrepresented non-English publications, introducing a potential language bias. The bibliometric approach also emphasizes publication volume and citation impact, which may not always correlate directly with clinical significance or methodological rigor. Further integration of cross-database searches and broader inclusion criteria may enhance future bibliometric analyses in this field.

5. Conclusions

MMA embolization is rapidly emerging as a minimally invasive treatment option for chronic subdural hematoma. This bibliometric analysis highlights a substantial increase in research activity, led by collaborative networks of specialized centers and influential authors. As research in this field expands, particularly with multi-center trials and longitudinal studies, embolization could become a valuable addition to cSDH management, offering a safer, less invasive alternative to conventional surgery.