Pedicle screw rupture: A case study

• This work shows the role in a justice case of a metallurgical analysis of dorsal implant failure.
• This work shows the impact of quality of machining process in the life of a mechanical component.
• This work shows how to identify mechanical, metallurgical and clinical causes of prosthetic failure.
• This work is a detailed study of mechanical and metallurgical properties of titanium alloy implants.
• This work describes a detailed analysis showing the causes of failure of dorsal prosthetics implants.

In this work we present a technical description related to the rupture of a titanium alloy pedicle screw and connecting bar implanted in dorsal vertebras of a patient. Only metallurgical facts are described, with no attempt to identify any imperfections in the clinical aspects related to the rupture. The results described here are based on extensive analysis of the broken materials in a material sciences specialized laboratory. Excluding an incorrect prosthesis implantation in the surgical procedure and a possible low bone density, an information not available to the research team, with high probability the rupture of metallic pieces used in the prosthetic implant, was produced by the low fatigue resistance resulting by an improper machining process and excessive bending of the connecting bar prior to implant.