A new semirigid implant for instrumentation of scoliosis: preliminary report

Abstract

A new set of pedicle screws, lamina and pedicle hooks, longitudinal rods and a titanium cable was developed to overcome the increasingly obvious hazards of overly rigid spinal instrumentation. Results of the first 12 consecutive scoliosis patients with this new system are reported, with an average follow-up time of 18 months. No major complications occurred. The average correction of the deformity was well within the range of more rigid systems. The new Dorsal Dynamic Spondylodesis (DDS) system proved to be easy to use, fast, powerful, safe, versatile, and biomechanically sound. Reduction of stress-shielding effects and protection of adjacent segments can be expected, and the system warrants future application in selected prospective cases with long-term follow-up.

Clinical and Radiological Comparison of Semirigid (WavefleX) and Rigid System for the Lumbar Spine

“…Posterior rigid fixation in lumbar arthrodesis could offer greater stabilization and a higher fusion rate. Overly rigid spinal instrumentation is known to carry the inherent danger of segment instability adjacent to the fused levels, as well as stress shielding and bone-implant interface failure, with cascading pseudarthrosis 1 10 18 21) . Semirigid fixation combined with lumbar arthrodesis seems to be able to decrease the loading of adjacent segments when compared with rigid fixation, whic h prompted the development of a spinal implant material with an optimum stiffness that could promotefusion 1 14 21) .…”