Computer aided spine surgery. What's new fifteen years later ?

The first navigation systems for spine surgery were introduced in the mid 90's to optimize pedicle screws insertion. Both technologies are still used: CT-based navigation and fluoronavigation (2D fluoronavigation) system which can be considered as an alternative to CT- based navigation technology. Three new technologies were introduced in the late 2000's and can be added to the orthopedic intra-operative arsenal for spine surgery. The 3D isocentric fluoroscope is a new type of fluoroscope, able to provide intra-operative CT-like images without the need of registration process. With templating technology, patient's CT data is used to simulate and plan preoperatively the pedicle screw trajectory on a computer workstation. A rapid prototyping technology provides templates that are intraoperatively attached to the back side of the spine at their appropriate position, thanks to the precise representation of the bony surface. Then, each drill can be carried out accurately, exactly where it has been planned. The small robots such as "Bone Mounted Robots" can be fixed directly within the operating field. With CT- based navigation technology, and a 3D - 2D registration process, they demonstrated their ability to help the surgeon to perform pedicle drilling with a high degree of accuracy. Meta-analyzes show that 3D fluoroscopic navigation systems are slightly more accurate than CT based and 2D fluoroscopic navigation systems. In terms of radiation dose, 3D fluoroscopic navigation seems less radiating than conventional fluoroscopy, but this remains to be proven formally. The results for a large-scale clinical use of the bone-mounted robot and templates are not yet known and their clinical application field is being to be considered.