Abstract
This chapter is divided into four primary sections. The first (Evolution of computer-assisted navigation section) discusses the history and evolution of intraoperative computer-assisted navigation, beginning with a brief introduction of frame-based stereotaxis and subsequently exploring the development of frameless techniques and their extension to spinal applications. Section Evolution of computer-assisted navigation concludes by delineating the clinical rationale as well as limits to adoption of spinal navigation techniques. Section Registration, imaging, and actuation techniques in spinal computer-assisted navigation summarizes current imaging and registration techniques for contemporary navigation systems, including their relative merits and drawbacks. This section concludes with a description of instrument tracking and actuation techniques, including a comparison of freehand, freehand-navigated, and robotically actuated mechanisms.