Bone repair and enhancement clinical trial design. Spine applications

Spine fusion represents over half of all current bone grafting procedures. It is an important clinical area for bone augmentation because use even of the most successful graft material, autogenous iliac crest bone, is fraught with an unacceptably high failure rate. Various new options that biologically will control bone induction currently are under development. To prevent unnecessary clinical failures, it is important that surgeons understand the principles of clinical trial design, whether they actively are using the reported results or simply reviewing them in an effort to decide if they will use the new technology in their own practice. This review highlights the important issues relevant to designing a clinical trial for studying the efficacy of a bone augmentation product in a spine application. Some of the design challenges are generic, but others are unique to the spine because of difficulty in defining a clear diagnostic group, difficulty in noninvasively assessing the technical success of surgery, and frequent dissociation of the clinical and radiographic results.