Accuracy of pedicle screw insertion with and without computer assistance: a randomised controlled clinical study in 100 consecutive patients

We performed a randomised controlled study to assess the accuracy of comput er-assisted pedicle screw insertion versus conventional screw placement und er clinical conditions. One hundred patients scheduled for posterior thorac olumbar or lumbosacral pedicle screw instrumentation were randomised into t wo groups, either for conventional pedicle screw placement or computer-assi sted screw application using an optoelectronic navigation system. From the computer-assisted group, nine patients were excluded: one because of an ina dequate preoperative computed tomography study, seven because of problems w ith the specific instruments or the computer system, and one because of an intraoperative anesthesiological complication. Thus, there were 50 patients in the conventional group and 41 in the computer-assisted group, and the n umber of screws inserted was 277 and 219, respectively. There was no statis tical difference between the groups concerning age, gender, diagnosis, type of operation performed, mean operating time, blood loss; or number of scre ws inserted. The time taken for screw insertion was significantly longer in the computer-assisted group. Postoperatively, screw positions were assesse d by an independent radiologist using a sophisticated CT imaging protocol. The pedicle perforation rate was 13.4% in the conventional group and 4.6% i n the computer-assisted group (P = 0,006). Pedicle perforations of more tha n 4 mm were found in 1.4% (4/277) of the screw insertions in the convention al group, and none in the computer-assisted group. Complications not relate d to pedicle screws were two L5 nerve root lesions, one end plate fracture, one major intraoperative bleeding and one postoperative death in the conve ntional group, and one deep infection in the computer-assisted group. Tn co nclusion, pedicular screws were inserted more accurately with image-guided computer navigation than with conventional methods.