[Accuracy of pedicle screw insertion in the thoracolumbar spine using image-guided navigation]

Computer image guidance is one of the most significant technologic advancements in the spine surgery, because preoperative or intraoperative images can be used for multiplanar, three-dimensional intraoperative navigation.

We performed a prospective clinical study to assess the accuracy of pedicle screw insertion using an optoelectronic navigation system (SurgiGATE Spine 2.1 Medivision). The study population included 29 patients with diverse disorders of the thoraco- lumbar spine (degenerative 54%, spondylolisthesis 21%, fractures 14%, scoliosis 7% and spondylodiscitis 4%). One patient was excluded from the study because problems with the specific instruments or the computer system. Pre and post-operative axial computed tomography images were obtained for each patient and analyzed by two independent radiologists to placement accuracy. The correct location was defined accord to Heary scale in 5 grades.

163 image-guided thoraco-lumbar pedicle screws were placed 29 in the thoracolumbar spine and 134 in the lumbosacral spine. We achieved a completely intraosseous placement (Grade I) in 99.4% of lumbosacral spine screws and 100% of thoracolumbar spine screws. Only one misplaced screw (Grade III) in the pedicle of L III in the concavity of a scoliosis was reported. No implant related complications were noted.

The low rate of misplaced screws in this prospective study compares favorably with previously published results. Our initial results indicate that Image-guided spinal surgery is a safe technique which improves surgical performance during posterior transpedicle stabilization.