Evidence for Efficacy of Pedicle-Based Systems

Abstract

There are now quite a range of randomized trials investigating spinal fusion and instrumentation of the lumbar spine in degenerative disorders. A meta-analysis of eight studies supports the conclusion that instrumentation increases fusion rates (Odds Ratio 2.3 (95% CI 1.1–4.8)), but not clinical outcome. My conclusion, looking at four studies where the role of pedicle screws can be analyzed, would be that using posterior instrumentation that includes pedicle screws will increase the fusion rate. But, it also increases length of surgery, the complication rate, the revision rate, and hence, the cost of surgery over an uninstrumented fusion. If we look down the line at the clinical outcome, there seems little to favour instrumentation over non-instrumented fusion. Pedicle screws are widely used to secure fixation of implants to the spine. Most spinal implant systems include pedicle screws in their inventory. This article summarizes evidence that pedicle screws work or fail in a variety of applications. Biomechanical test generally finds screws to be superior to other methods of fixation. Posterior implant systems seem more secure than no fixation, either with rigid or non-rigid systems.