PEDICLE SCREW PLACEMENT USING IMAGE-GUIDED TECHNIQUES

Clinical evaluation of a computer assisted spine surgical system is pr esented. Eighty pedicle screws were inserted using computer assisted t echnology in thoracic and lumbar vertebrae for treatment of different types of disorders including fractures, spondylolisthesis, and scolios is, Fifty-two patients with severe fractures, spondylolisthesis, or ps eudoarthrosis of T10 to L5 were treated using a computer assisted tech nique on 1/2 the patients and performing the screw insertion manually for the other 1/2. At the same time, 28 pedicle screws were inserted i n T12 to L4 vertebrae for scoliosis with the help of the computer assi sted technique. Surgery was followed in all cases (66 vertebrae; 132 p edicle screws) by postoperative radiographs and computed tomographic e xamination, on which measurements of screw position relative to pedicl e position could be done. For fractures, spondylolisthesis, or pseudar throsis, comparison between the two groups showed that four screws in 52 (8%) vertebrae had incorrect placement with computer assisted techn ique whereas 22 screws in 52 (42%) vertebrae had incorrect placement w ith manual insertion. In patients with scoliosis, four screws in 28 (1 4%) vertebrae had incorrect placement. In all of the patients (132 ped icle screws) there were no neurologic complications. These results sho w that a computer assisted technique is much more accurate and safe th an manual insertion.