Simultaneous registration with ct-fluoro matching for spinal navigation surgery. A case report.

Computer-assisted surgery, which provides simultaneous, multiplanar images of bone structures, has become widely used. However, registration maneuvering remains time consuming. The objective of this paper is to document the usefulness of CT-fluoro matching for spinal navigation. A spinal navigation system (VECTORVISION compact; Brain LAB, Germany) and a digital imaging system (OEC9800; CATHEX, Tokyo, Japan) were used for CT-fluoro matching in cases of L4/5 and L5/S1 posterior lumbar interbody fusion. A reference array was attached to the L4 spinous process. Preoperative CT images and intraoperative fluoro-shots including L4, L5, and S1 were superimposed on the navigation monitor. Following insertion of L4 screws, a reference array remained to be attached to the L4 spinous process, after which a level definition and pre-registration of L5 and S1 vertebrae were performed and the screwing procedure of L5 and S1 was completed without additional fluro-shots. Registration of three vertebrae was completed without paired-point or surface-matching procedures. The calculation time for the registration in a single vertebra was 30 sec. All pedicle screws were seen to be successfully inserted on postoperative CT images. We performed the navigation surgery by matching the preoperative CT images to the intraoperative fluoro-shots without manual registration. This technique may prove useful in the future for anterior spinal surgery and percutaneous screwing without the need for total exposure of the bone surface.