Environmental impacts of patient-specific scoliosis brace fabrication: a life cycle comparison of manual casting, 3D-scanned thermoforming, and 3D printing

Patient-specific scoliosis braces can be fabricated through conventional casting and thermoforming or digital workflows integrating 3D scanning and additive manufacturing. These fabrication pathways differ in their material and energy requirements and, consequently, their environmental impacts. As sustainability is an increasing concern among younger generations, the ecological footprint of scoliosis treatment may also matter to patients and families. Comparing these impacts can provide an additional criterion for evaluating alternative scoliosis brace fabrication methods. This study quantifies and compares the environmental impacts of three fabrication methods: manual-casted thermoforming, 3D-scanned thermoforming, and 3D-scanned 3D printing. Life cycle assessment was conducted using the ReCiPe 2016 Midpoint method across 18 environmental impact indicators. The functional unit was one patient-specific scoliosis brace for a representative adolescent, produced in Québec. A cradle-to-gate system boundary was applied. Material and energy inputs associated with each fabrication pathway were assessed, and contribution analysis identified the main sources of environmental impact. The 3D-scanned thermoforming pathway showed the highest normalized impact across most midpoint indicators, with polyurethane as its dominant contributor. Manual-casted thermoforming generally showed intermediate impacts but had the highest impacts for freshwater eutrophication, marine ecotoxicity, and water consumption. In contrast, 3D-scanned 3D printing showed the lowest normalized impact for most indicators. For 3D printing, polypropylene and electricity were the principal contributors, with their relative importance varying across impact categories. These findings show that fabrication pathway selection can substantially influence the environmental impacts of patient-specific scoliosis braces. Life cycle environmental impacts can therefore provide a complementary criterion alongside clinical and technical considerations when comparing scoliosis brace fabrication methods. Considering sustainability in brace fabrication may also better align scoliosis care with patient and family concerns and potentially support treatment engagement.