Features of manufacturing and clinical application of porous titanium implants for treatment of injuries and diseases of the spine

When treating injuries and diseases of the spine, it becomes necessary to replace the vertebral body or intervertebral disc with an implant. Such an implant should ensure the performance of the supporting function of the spine and facilitate the formation of a bone block (fusion). For this purpose, the most effective can be considered porous titanium that meets the requirements for biocompatibility, strength characteristics and rigidity. The possibility of obtaining such implants by diffusion welding of a specially twisted wire made of VT1-0 alloy and subsequent thermal hydrogen treatment, including thermal diffusion saturation of the implant blank with hydrogen and its subsequent removal during vacuum annealing, is considered. It is shown, that thermal hydrogen treatment makes it possible to transform the mechanical contacts of the wire after diffusion welding of the work piece into physicochemical ones. This makes it possible to increase the strength characteristics of the implant with a high volumetric porosity (up to 60-70 %) and bring its rigidity closer to the rigidity of the vertebrae. Optimization of the modes of diffusion welding and thermal hydrogen treatment was carried out to obtain a high complex of strength and plastic characteristics of implants. Clinical studies of the use of porous implants obtained by the proposed technology have shown their high efficiency in the treatment of injuries and diseases in the cervical, thoracic and lumbar spine. 247 clinical cases of the use of "cellular" porous implants (54 patients with injuries and 193 with degenerative-dystrophic diseases of the spine) were considered. In 214 cases, an improvement in the condition of patients was noted (86.6 %). Deterioration was observed in 4 patients (1.6 %), which was associated with contusion and edema of the spinal cord after the injury. It was found that in a relatively short period (up to 5-6 weeks), through the growth of bone tissue occurs through the implant. In this case, the formation of osteophytes on the lateral surface of the implant is not observed, which reduces the likelihood of injury.