Fabrication of Artificial Intervertebral Spacer by Functionally Graded Zirconia
When problems with the spine of the human body occur, symptoms such as pain and numbness arise, causing impediments to everyday life. In addition, when these symptoms are severe, surgery is required. In recent years, the number of spinal operations performed has tended to increase, and accordingly, there has been an increase in the number of the spinal spacers used in fusion surgeries.In this study, we focused on zirconia as a spacer material because it is superior in terms of strength, toughness, and frictional wear characteristics and does not cause a foreign body response such as metal allergy. Therefore, our purpose was to make adjustments for mechanical characteristics that were suitable for use in spacers by combining a dense structure of zirconia with a porous structure. A further purpose was to fabricate a spinal spacer capable of strong, direct bonding with vertebrae. During the fabrication we packed a powdered mixture of zirconia powder and carbon, the source of the pores, and sintered this using a spark plasma sintering method. Thereafter, the source of the pores was eliminated by heating, and bioactivity was provided by immersion in an aqueous solution of NaOH. Observations and analysis made using a scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) allowed us to fabricate materials suitable for our purposes. We are reporting this method as well as the stress occurring at the interface of the layers.
T. Chandra, M. Ionescu and D. Mantovani
T. Fujii and T. Asaoka, "Fabrication of Artificial Intervertebral Spacer by Functionally Graded Zirconia", Advanced Materials Research, Vol. 409, pp. 136-141, 2012