Analysis of Retrieved Scoliosis Instrumentation

· (a – Synos Foundation; Cervical Spine Research Society)

Engineering analysis of retrieved spine implants can yield information about the in-service performance and mechanisms of failure of these devices. As part of our ongoing Philadelphia-based spine implant retrieval program we have performed analysis of four scoliosis instrumentation systems. The levels implanted were T4-L2, T5-L4, T4-L4 and L4-S1. The average implantation time, for the implants studied, was 2.8 years. A variety of modes of in-service damage were observed. Metal wear, indicative of load transfer, and corrosion was observed at interfaces between the longitudinal rods and other elements. The most severe damage was observed at cross-brace locations followed by pedicle screws and then hooks.

· If noted, the author indicates something of value received. The codes are identified as: a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options.