Institute For Biomedical Engineering (IBE)

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Browsing Institute For Biomedical Engineering (IBE) by Author "Kotze, L"

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    Cost Analysis of an Additive Manufacturing Laboratory for 3D Printed Anatomical Models in Orthopaedic Pre-Surgical Planning and Surgery.
    (Stellenbosch : Stellenbosch University, 2023-03) Kotze, L; Van der Merwe, J; Venter, RG; Stellenbosch University. Faculty of Engineering. Institute of Biomedical Engineering.
    ENGLISH ABSTRACT: The primary problem to be investigated is the need to know how much the individual activities of the three-dimensional printing (3DP) production process contribute to the overall cost per patient. How much to quote internal orthopaedic surgeons before performing the 3DP production process is also unknown and the secondary problem to be investigated. Lastly, the tertiary problem to be investigated is the need to know how much samples 3D printed in different filaments would melt or deform after being exposed to low-temperature ethylene oxide (EtO) or autoclave sterilisation. In the 3DP production process, the investigator used dedicated software packages to create virtual 3D anatomical models from patients’ anonymised computed tomography (CT) or magnetic resonance imaging (MRI) scans for Fused Filament Fabrication (FFF) 3DP (designated as simulation models) and EtO or autoclave sterilisation (designated as haptic maps). Afterwards, a cost estimation model was developed to estimate the direct cost per patient, which was validated by comparing the cost estimates to the cost model results of three new patient cases. Furthermore, samples made from acrylonitrile butadiene styrene (ABS), nylon and polylactic acid (PLA) were sterilised by using low-temperature EtO and autoclave sterilisation. Thereafter, samples were measured with a digital vernier calliper to obtain postprinting and post-sterilisation linear measurements in metres (m). Results were expressed as means ± standard deviations for the total linear differences and absolute percentage errors. In the cost model study, image segmentation and manufacturing costs contributed 31 % and 45 % to the direct cost per patient, respectively. The direct costs of two patient cases were overestimated by 61 % and 74 %, respectively. In conclusion, optimising the image segmentation and manufacturing times of the 3DP production process may make medical 3DP more viable for use in orthopaedic applications and reduce the direct cost per patient. Also, the cost model may not be accurate to estimate the direct cost per patient due to the overestimation of costs in the validation dataset. In the dimensional accuracy testing study, ABS (-1,03E-5 ± 1,65E-4 m) and PLA (-1,01E-4 ± 4,62E-4 m) were the most affected by EtO sterilisation and shrunk in mean linear differences as opposed to nylon (6,43E-6 ± 2,08E-4 m). Furthermore, ABS (-2,52E-4 ± 1,28E-3 m) and PLA (-2,30E-4 ± 7,06E-4 m) were the most affected by autoclave sterilisation and shrunk more in mean linear differences as opposed to nylon (-4,20E-5 ± 2,96E-4 m). To conclude, nylon was preferred as a suitable material for both low-temperature EtO (preferably) and autoclave sterilisation to sterilise haptic maps. The primary problem to be investigated is the need to know how much the individual activities of the three-dimensional printing (3DP) production process contribute to the overall cost per patient. How much to quote internal orthopaedic surgeons before performing the 3DP production process is also unknown and the secondary problem to be investigated. Lastly, the tertiary problem to be investigated is the need to know how much samples 3D printed in different filaments would melt or deform after being exposed to low-temperature ethylene oxide (EtO) or autoclave sterilisation. In the 3DP production process, the investigator used dedicated software packages to create virtual 3D anatomical models from patients’ anonymised computed tomography (CT) or magnetic resonance imaging (MRI) scans for Fused Filament Fabrication (FFF) 3DP (designated as simulation models) and EtO or autoclave sterilisation (designated as haptic maps). Afterwards, a cost estimation model was developed to estimate the direct cost per patient, which was validated by comparing the cost estimates to the cost model results of three new patient cases. Furthermore, samples made from acrylonitrile butadiene styrene (ABS), nylon and polylactic acid (PLA) were sterilised by using low-temperature EtO and autoclave sterilisation. Thereafter, samples were measured with a digital vernier calliper to obtain postprinting and post-sterilisation linear measurements in metres (m). Results were expressed as means ± standard deviations for the total linear differences and absolute percentage errors. In the cost model study, image segmentation and manufacturing costs contributed 31 % and 45 % to the direct cost per patient, respectively. The direct costs of two patient cases were overestimated by 61 % and 74 %, respectively. In conclusion, optimising the image segmentation and manufacturing times of the 3DP production process may make medical 3DP more viable for use in orthopaedic applications and reduce the direct cost per patient. Also, the cost model may not be accurate to estimate the direct cost per patient due to the overestimation of costs in the validation dataset. In the dimensional accuracy testing study, ABS (-1,03E-5 ± 1,65E-4 m) and PLA (-1,01E-4 ± 4,62E-4 m) were the most affected by EtO sterilisation and shrunk in mean linear differences as opposed to nylon (6,43E-6 ± 2,08E-4 m). Furthermore, ABS (-2,52E-4 ± 1,28E-3 m) and PLA (-2,30E-4 ± 7,06E-4 m) were the most affected by autoclave sterilisation and shrunk more in mean linear differences as opposed to nylon (-4,20E-5 ± 2,96E-4 m). To conclude, nylon was preferred as a suitable material for both low-temperature EtO (preferably) and autoclave sterilisation to sterilise haptic maps.