Computer assistance has been shown to improve significantly the accuracy and safety of pedicle screw insertion under clinical conditions. The technique of image-guided navigation is described in this article, based on the authors' clinical experience of over 4 years. The value of navigation systems for preoperative planning is discussed. Clinical results of the application of this new method in the cervical, thoracic, and lumbosacral spine as well as the iliosacral joints are presented by means of the authors' own studies and reports from the literature. Pros and cons of computer guidance are discussed. The authors predict computer navigation will be used in percutaneous and minimally invasive procedures in the near future.