Skin Combatibility with 3d Printed Splints And Casts

PURPOSE: 3D printed limb orthotics offer hygienic advantages over traditional technology because no padding is needed. We investigated biocompatibility and chemical profile of 3D printed material in contact with skin. METHODS: Patient-specific 3D printed ABS polymer casts from multiple sources of feedstock were evaluated according to ISO 10993 standards used by FDA for review of biocompatibility. The effect of post-processing with acetone vapor was evaluated as an independent variable. Cytotoxicity testing using L929 fibroblast reactivity, sensitization by Kligman Maximization methods in Guinea Pigs and irritation evaluation by intracutaneous injection in New Zealand White Rabbits of 3D print extractions were conducted under GLP conditions. In addition, mass spectrometry of filament feedstock and 3D printed casts was performed on solvent extractions using DART methods. RESULTS: Finished casts met criteria for permanent contact with skin and limited contact with mucosal membranes. Mass spectrometry findings indicated that changes in ABS polymer occurred with 3D printing and post-processing in both surface and internal chemistry. However, these chemical changes did not compromise biocompatibility assessed under ISO 10993. CONCLUSIONS: Patient-specific 3D printed, ABS orthotics met industry standards for biocompatibility for extended patient skin contact despite changes in material chemistry from feedstock. Therefore, testing and adherence to specific manufacturing controls is necessary to assure patient safety. Mass spectrometry assessment of composition of ABS polymers may serve to continually monitor product quality of 3D printed medical devices in accordance with 21 CFR 820.30. This work was supported in part by a CERSI grant to University of Maryland from the US FDA (U01FD005946A). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the HHS or FDA.