3D printing orthopedic scoliosis braces: a test comparing FDM with thermoforming

Davide Felice Redaelli, Valentina Abbate, Fabio Alexander Storm, Alfredo Ronca, Andrea Sorrentino, Cristina De Capitani, Emilia Biffi, Luigi Ambrosio, Giorgio Colombo, Paolo Fraschini

Research output: Contribution to journalArticlepeer-review

Abstract

In recent years, 3D printing gained considerable attention in the orthopedic sector. This work evaluates the feasibility of producing orthopedic scoliosis braces by 3D printing, comparing performance and costs with classical thermoforming procedures. Critical parameters, such as manufacture time, mechanical properties, weight, and comfort are carefully considered. Polyethylene terephthalate glycol-modified (PETG) was selected among the several filaments materials present on the market. Printed samples were analyzed with electronic microscope, tensile, and impact tests and compared with thermoformed polyethylene (PE) and polypropylene (PP) samples. Moreover, a cost analysis was carried out for the specific application. The thermoformed brace of a volunteer patient affected by scoliosis was reproduced using reverse-engineering techniques. The model was then printed as a single piece and postprocessed by an expert orthotist. Subsequently, the patient wore the brace in a pilot case to compare comfort and mechanical effectiveness. Results show that the 3D printing fabrication method is able to provide a valid alternative to the current fabrication methods, being also very competitive in terms of costs. The morphological analysis does not show critical defects in 3D printed samples, while the mechanical tests highlighted their anisotropy, with an overall brittleness of PETG samples in the direction orthogonal to the fibers. However, in terms of mechanical stresses, a back brace should never reach the polymer yield stress, otherwise the shape would be modified and the therapeutic effect could be compromised. Finally, the patient reported the perception of improved support and no significant comfort differences compared with the thermoformed brace.

Original languageEnglish
Pages (from-to)1707-1720
Number of pages14
JournalInternational Journal of Advanced Manufacturing Technology
Volume111
DOIs
Publication statusPublished - 2020

Keywords

  • 3D printing
  • FDM
  • Manufacturing process
  • Mechanical characterization
  • Orthopedic scoliosis brace
  • PETG

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Software
  • Mechanical Engineering
  • Computer Science Applications
  • Industrial and Manufacturing Engineering

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