Fabrication of Synthetic Lumbar Vertebrae by a Combination of FDM 3D-Printing and PU Foam Casting from Two Injection Techniques for Surgical Training
Keywords:
3D printing, Lumbar, Polyurethane foam, Surgical training, Synthetic boneAbstract
This study aims to introduce a rapid and precise fabrication
technique of lumbar vertebrae model that mimics the
cortical and cancellous parts of the bone using polylactic acid
(PLA) and polyurethane (PU) foam, respectively. An FDM 3Dprinting using PLA filament was utilized to fabricate the
cortical part, then PU foam was molded into the printed
cortical to form the cancellous part. The fabricated model
was examined by comparing its dimensions with the
stereolithography (STL) model. Sequentially, density
measurement, compressive test, and microstructure
observation were performed to evaluate the specimen
characteristics. The results showed that the dimensions of
the vertebrae model agreed well with the STL model, with a
discrepancy of less than 4%. The fabricated PU samples
exhibited a density in the range of 476–557 kg/m³, elastic
moduli of 3.99–7.17 MPa, and a pore size of 136.66–179.80
µm, which are lower than the properties of human bone.
Despite that, the PU samples maintain their compressive
strength of 0.329–0.589 MPa, which is within the range of
cancellous human bone.
References
Akbaş, O. E., Hıra, O., Hervan, S. Z., Samankan, S., and Altınkaynak, A. (2020). Dimensional
accuracy of FDM-printed polymer parts. Rapid Prototyping Journal, 26(2), 288-298.
Alafaghani, A. A., Qattawi, A., Alrawi, B., and Guzman, A. (2017). Experimental optimization
of fused deposition modelling processing parameters: a design-for-manufacturing
approach. Procedia Manufacturing, 10, 791-803.
Al-Atroush, M. E., and Sebaey, T. A. (2021). Stabilization of expansive soil using hydrophobic
polyurethane foam: A review. Transportation Geotechnics, 27, 100494.
Alsoufi, M. S., Alhazmi, M. W., Suker, D. K., Alghamdi, T. A., Sabbagh, R. A., Felemban, M. A.,
and Bazuhair, F. K. (2019). Experimental characterization of the influence of nozzle
temperature in FDM 3D printed pure PLA and advanced PLA+. American Journal of
Mechanical Engineering, 7(2), 45-60.
Asriyanti, A., Saptaji, K., Khoiriyah, N., Utomo, M. S., Dwijaya, M. S., Triawan, F., and Nadhif,
M. H. (2022). Fabrication of rigid polyurethane foam lumbar spine model for surgical
training using indirect additive manufacturing. International Journal of Technology, 13,
Atesok, K., Mabrey, J. D., Jazrawi, L. M., and Egol, K. A. (2012). Surgical simulation in
orthopaedic skills training. JAAOS-Journal of the American Academy of Orthopaedic
Surgeons, 20(7), 410-422.
Blair-Pattison, A. (2016). Development and characterization of a synthetic bone analogue for
surgical training. Development, 2016, 01-18.
Bohl, M. A., Zhou, J. J., Mooney, M. A., Repp, G. J., Cavallo, C., Nakaji, P., and Kakarla, U. K.
(2019). The Barrow Biomimetic Spine: effect of a 3-Dimensional-Printed spinal osteotomy
model on performance of spinal osteotomies by medical students and interns. Journal of
Spine Surgery, 5(1), 58.
Brown, A. D., Walters, J. B., Zhang, Y. X., Saadatfar, M., Escobedo-Diaz, J. P., and Hazell, P. J.
(2019). The mechanical response of commercially available bone simulants for quasistatic and dynamic loading. Journal of the Mechanical Behavior of Biomedical
Materials, 90, 404-416.
Clifton, W., Nottmeier, E., Damon, A., Dove, C., Chen, S. G., Pichelmann, M., & Chen, S. (2019).
A feasibility study for the production of three-dimensional-printed spine models using
simultaneously extruded thermoplastic polymers. Cureus, 11(4), 1-6.
Clifton, W., Pichelmann, M., Vlasak, A., Damon, A., ReFaey, K., and Nottmeier, E. (2020).
Investigation and feasibility of combined 3D printed thermoplastic filament and
polymeric foam to simulate the corticocancellousinterface of human vertebrae. Scientific
Reports, 10(1), 2912.
Ergene, B., ŞEKEROĞLU, İ., Bolat, Ç., and Yalçın, B. (2021). An experimental investigation on
mechanical performances of 3D printed lightweight ABS pipes with different cellular wall
thickness. Journal of Mechanical Engineering and Sciences, 15(2), 8169-8177.
Frost, B. A., Camarero-Espinosa, S., and Foster, E. J. (2019). Materials for the spine: anatomy,
problems, and solutions. Materials, 12(2), 253.
Galbusera, F., and Bassani, T. (2019). The spine: a strong, stable, and flexible structure with
biomimetics potential. Biomimetics, 4(3), 60.
Garg, B., and Mehta, N. (2018). Current status of 3D printing in spine surgery. Journal of
Clinical Orthopaedics and Trauma, 9(3), 218-225.
Geier, S., Winkler, C., and Piesche, M. (2009). Numerical simulation of mold filling processes
with polyurethane foams. Chemical Engineering & Technology: Industrial Chemistry‐Plant
Equipment‐Process Engineering‐Biotechnology, 32(9), 1438-1447.
Gerhardt, L. C., and Boccaccini, A. R. (2010). Bioactive glass and glass-ceramic scaffolds for
bone tissue engineering. Materials, 3(7), 3867-3910.
Ghomi, E. R., Khosravi, F., Neisiany, R. E., Singh, S., and Ramakrishna, S. (2021). Future of
additive manufacturing in healthcare. Current Opinion in Biomedical Engineering, 17,
Hatchett, D. W., Kinyanjui, J. M., and Sapochak, L. (2007). FTIR analysis of chemical gradients
in thermally processed molded polyurethane foam. Journal of Cellular Plastics, 43(3),
-196.
Heiner, A. D., and Brown, T. D. (2001). Structural properties of a new design of composite
replicate femurs and tibias. Journal of Biomechanics, 34(6), 773-781.
Houben, A., Van Hoorick, J., Van Erps, J., Thienpont, H., Van Vlierberghe, S., and Dubruel, P.
(2017). Indirect rapid prototyping: opening up unprecedented opportunities in scaffold
design and applications. Annals of Biomedical Engineering, 45, 58-83.
Husemoglu, R. B., Baysan, G., Ertugruloglu, P., Yücel, A. T., and Havıtçıoğlu, H. (2020). The
mechanical comparison of artificial bone and 3D printed bone segments. Journal of
Medical Innovation and Technology, 2(2), 127-130.
Jackovich, D., O'toole, B., Hawkins, M. C., and Sapochak, L. (2005). Temperature and mold size
effects on physical and mechanical properties of a polyurethane foam. Journal of Cellular
Plastics, 41(2), 153-168.
Kang, S. W., Yang, H. S., Seo, S. W., Han, D. K., and Kim, B. S. (2008). Apatite‐coated poly (lactic‐
co‐glycolic acid) microspheres as an injectable scaffold for bone tissue
engineering. Journal of Biomedical Materials Research Part A, 85(3), 747-756.
La Nasa, J., Biale, G., Ferriani, B., Colombini, M. P., and Modugno, F. (2018). A pyrolysis
approach for characterizing and assessing degradation of polyurethane foam in cultural
heritage objects. Journal of Analytical and Applied Pyrolysis, 134, 562-572.
Lee, W. H., Lee, S. W., Kang, T. J., Chung, K., and Youn, J. R. (2002). Processing of
polyurethane/polystyrene hybrid foam and numerical simulation. Fibers and Polymers, 3,
-168.
Liu, G., Liao, H., Zhao, X., Liao, W. H., and Cao, J. (2024). Haptic device and interface to
reproduce force and tactile feedback of biological tissues. Sensors and Actuators A:
Physical, 366, 115022.
Liu, W., Zhang, S., Li, Y., and Ye, X. (2023). The expansion and mechanical property-based
cavity expansion model for polyurethane grouting underneath the airport
pavement. Transportation Geotechnics, 43, 101141.
Lughmani, W. A., Bouazza-Marouf, K., and Ashcroft, I. (2015). Drilling in cortical bone: a finite
element model and experimental investigations. Journal of The Mechanical Behavior of
Biomedical Materials, 42, 32-42.
Moles, J. J., Connelly, P. E., Sarti, E. E., and Baredes, S. (2009). Establishing a training program
for residents in robotic surgery. The Laryngoscope, 119(10), 1927-1931.
Morgan, E. F., Unnikrisnan, G. U., and Hussein, A. I. (2018). Bone mechanical properties in
healthy and diseased states. Annual review of Biomedical Engineering, 20(1), 119-143.
Nery, B., Rivero, L. R., Camporeze, B., Costa, R. A. F., Pereira, L. C., Quaggio, E., and Nery, C. S.
A. (2021). Use of three-dimensional reconstruction in 3D molds as an adjuvant in the
treatment of cranial and spinal pathologies: technical details and case
report. Interdisciplinary Neurosurgery, 24, 100953.
Öhman‐Mägi, C., Holub, O., Wu, D., Hall, R. M., and Persson, C. (2021). Density and mechanical
properties of vertebral trabecular bone—A review. JOR Spine, 4(4), e1176.
Özdemir, İ. B., and Akar, F. (2018). 3D simulation of polyurethane foam injection and reacting
mold flow in a complex geometry. Heat and Mass Transfer, 54(5), 1281-1288.
Parsons, N. S., and Mountain, C. A. (2007). Investigating polyurethane foam as a form of trace
evidence. Science & Justice, 47(1), 24-33.
Ravindra, V. M., Senglaub, S. S., Rattani, A., Dewan, M. C., Härtl, R., Bisson, E., and Shrime, M.
G. (2018). Degenerative lumbar spine disease: estimating global incidence and worldwide
volume. Global Spine Journal, 8(8), 784-794.
Reid, P. C., Morr, S., and Kaiser, M. G. (2019). State of the union: a review of lumbar fusion
indications and techniques for degenerative spine disease: JNSPG 75th Anniversary
Invited Review Article. Journal of Neurosurgery: Spine, 31(1), 1-14.
Rizvi, A., Chu, R. K., and Park, C. B. (2018). Scalable fabrication of thermally insulating
mechanically resilient hierarchically porous polymer foams. ACS Applied Materials &
Interfaces, 10(44), 38410-38417.
Ruikar, D. D., Hegadi, R. S., and Santosh, K. C. (2018). A systematic review on orthopedic
simulators for psycho-motor skill and surgical procedure training. Journal of Medical
Systems, 42, 1-21.
Saad, W. A., Dzahir, M. A. M., Shinichirou, Y., Hussein, M., Mohamad, M., Saad, S. M., and
Azaman, A. (2020). Comparison of the spine kinematics by defining lumbar as single and
multi-segmental in completing critical daily task. Journal of Mechanical Engineering and
Sciences, 14(4), 7600-7608.
Samkhaniani, N., Gharehbaghi, A., and Ahmadi, Z. (2013). Numerical simulation of reaction
injection molding with polyurethane foam. Journal of Cellular Plastics, 49(5), 405-421.
Schäfer, K., Nestler, D., Tröltzsch, J., Ireka, I., Niedziela, D., Steiner, K., and Kroll, L. (2020).
Numerical studies of the viscosity of reacting polyurethane foam with experimental
validation. Polymers, 12(1), 105.
Seehanam, S., Khrueaduangkham, S., Sinthuvanich, C., Sae-Ueng, U., Srimaneepong, V., and
Promoppatum, P. (2024). Evaluating the effect of pore size for 3D-printed bone
scaffolds. Heliyon, 10(4), e26005.
Senra, M. R., and Marques, M. D. F. V. (2020). Synthetic polymeric materials for bone
replacement. Journal of Composites Science, 4(4), 191.
Shull, P. B., and Damian, D. D. (2015). Haptic wearables as sensory replacement, sensory
augmentation and trainer–a review. Journal of Neuroengineering and Rehabilitation, 12,
-13.
Sparrey, C. J., Bailey, J. F., Safaee, M., Clark, A. J., Lafage, V., Schwab, F., and Ames, C. P. (2014).
Etiology of lumbar lordosis and its pathophysiology: a review of the evolution of lumbar
lordosis, and the mechanics and biology of lumbar degeneration. Neurosurgical
Focus, 36(5), E1.
Sun, M., Bi, Y., Zhuang, W., Chen, S., Zhao, P., Pang, D., and Zhang, W. (2021). Mechanism of
polyurethane binder curing reaction and evaluation of polyurethane mixture
properties. Coatings, 11(12), 1454.
Syahrom, A., Kadir, M. R. A., Harun, M. N., and Öchsner, A. (2015). Permeability study of
cancellous bone and its idealised structures. Medical Engineering & Physics, 37(1), 77-86.
Teraguchi, M., Yoshimura, N., Hashizume, H., Muraki, S., Yamada, H., Minamide, A., and
Yoshida, M. (2014). Prevalence and distribution of intervertebral disc degeneration over
the entire spine in a population-based cohort: the Wakayama Spine Study. Osteoarthritis
and Cartilage, 22(1), 104-110.
Wang, T. M., Lin, Y. C., Lan, Y. H., and Lin, L. D. (2022). Evaluation of sawbones training
protocol in bone quality classification using tactile sensation. Journal of Dental
Sciences, 17(2), 897-902.
Zhang, H., Wang, R., Song, Y., Wang, Y., and Hu, Q. (2024). Research on dual-phase composite
forming process and platform construction of radial gradient long bone
scaffold. Bioengineering, 11(9), 869.
Zharylkassyn, B., Perveen, A., and Talamona, D. (2021). Effect of process parameters and
materials on the dimensional accuracy of FDM parts. Materials Today: Proceedings, 44,
-1311.
