Medical 3D printing: methods to standardize terminology and report trends

Abstract

Background: Medical 3D printing is expanding exponentially, with tremendous potential yet to be realized in nearly all facets of medicine. Unfortunately, multiple informal subdomain-specific isolated terminological 'silos' where disparate terminology is used for similar concepts are also arising as rapidly. It is imperative to formalize the foundational terminology at this early stage to facilitate future knowledge integration, collaborative research, and appropriate reimbursement. The purpose of this work is to develop objective, literature-based consensus-building methodology for the medical 3D printing domain to support expert consensus.

Results: We first quantitatively survey the temporal, conceptual, and geographic diversity of all existing published applications within medical 3D printing literature and establish the existence of self-isolating research clusters. We then demonstrate an automated objective methodology to aid in establishing a terminological consensus for the field based on objective analysis of the existing literature. The resultant analysis provides a rich overview of the 3D printing literature, including publication statistics and trends globally, chronologically, technologically, and within each major medical discipline. The proposed methodology is used to objectively establish the dominance of the term "3D printing" to represent a collection of technologies that produce physical models in the medical setting. We demonstrate that specific domains do not use this term in line with objective consensus and call for its universal adoption.

Conclusion: Our methodology can be applied to the entirety of medical 3D printing literature to obtain a complete, validated, and objective set of recommended and synonymous definitions to aid expert bodies in building ontological consensus.

Keywords: 3D printing; Additive manufacturing; Data integration; Freeform fabrication; Medicine; Rapid prototyping; Standards; Terminology.

Fig. 1

Medical 3D printing publications available in PubMed by publication year, from 2000 to 2015

Fig. 2

Schematic representation of concept cluster analysis. Here, a literature corpus is represented on the left, with the concepts “A” and “B” always encountered together in published literature. This is reflected in these concepts closely clustering together on a proximity map. Concept “Z”, on the other hand, is isolated, and is well outside of the “AB” cluster on the map. Colors denote total concept use, with red reflecting maximal and green minimum use

Fig. 3

Publications primarily referencing “3D printing”, “rapid prototyping”, or “additive manufacturing” terms in the period from 2012 to 2015

Fig. 4

Heat map for concept clusters within 3D printing literature. Red corresponds to a large number of highly clustered and related concepts, while blue represents absence of relationships

Fig. 5

Concept clusters within 3D printing literature arranged as individual MeSH categories and clustered by distance within the literature. Colors correspond to major MeSH categories: red represents “Diseases”, green corresponds to “Chemicals and Drugs” and blue represents “Analytical, Diagnostic and Therapeutic Techniques and Equipment”. Circle size represents the relative number of papers annotated with a particular MeSH term, while distance reflects concept proximity

Fig. 6

Publications in 3D printing per medical discipline and the supporting imaging modalities used in each discipline. Please note that discipline and modality co-dominance is possible within a publication, leading to row sums exceeding the total provided

Fig. 7

General application categories in specific medical disciplines

Fig. 8

Printing technologies employed in major disciplines and applications, stratified by main manufacturing process and material category

Fig. 9

Global medical 3D printing activity, by the country of origin of the first author. Nations with over 25 publications are annotated on the map, with the exception of Switzerland, with 32 first author publications

Fig. 10

Usage of ‘additive manufacturing’ and ‘rapid prototyping’ in relation to ‘3D printing’, in percent. Although for the vast majority of fields, ‘3D printing’ is the relatively more frequently used term, dentistry and otolaryngology provide evidence for nascent terminological isolation, with ‘rapid prototyping’ being the more frequently used term