Security of 3D-printed polylactide acid piece sterilization in the operating room: a sterility test

Abstract

Introduction: 3D-printing technology has become very popular the last 10 years, and their advantages have been widely proved. However, its safety in the operating room after sterilization has not been evaluated. Thus, the use of 3D printing is still questioned. The aim of this work is to evaluate the security of polylactic acid (PLA) to print surgical models after its sterilization.

Materials and methods: One hundred and eighty-six PLA plates and 6 negative controls without microorganisms were seeded. After 10 days of culture, the PLA plates were randomized into three groups: A, B, and C. Group A underwent a sterilization process using an autoclave program at 134 °C. Group B was seeded in different culture media and group C was used to make crystal violet stains on the biofilms formed on the PLA. Mechanical properties of PLA after autoclave sterilization including, the breaking load, deformation and breaking load per surface were calculated.

Results: Hundred percent of the group B showed monomicrobial growth. Stains performed on group C PLA showed biofilms in all PLA pieces. After sterilization, no pathogen growth was observed in group A during the culture observation period showing 100% sterilization effectiveness. A filling percentage of 5% obtained a breaking load of 6.36 MPa, and its elastic limit occurred after an elongation of 167.4%. A 10% infill was mechanically safe.

Conclusions: Autoclave sterilization of PLA-printed pieces is safe for the patient and mechanically strong for the surgeon. This is the first 3D-printing protocol described and evaluated to implement 3D-printing technology safely in the operating room.

Significance and impact of study: This is the first 3D-printing protocol described to print and sterilize 3D biomodels using an autoclave showing its biological safety and its mechanical resistance.

Keywords: 3D printing; Custom made models; Polylactic acid sterilization.