**ACCURACY OF PEDICLE SCREW INSERTION WITH AND WITHOUT COMPUTER ASSISTANCE – A RANDOMISED CONTROLLED CLINICAL TRIAL IN 100 CONSECUTIVE PATIENTS

Timo Laine,
Teija Lund,
Mauno Ylikoski,
Jouni Lohikoski,
Dietrich Schlenzka
Helsinki, Finland

A randomised controlled clinical study was performed to assess the accuracy of computer assisted pedicle screw insertion versus conventional pedicle screw placement. One–hundred consecutive patients were randomly allocated into two groups for either conventional, or computer assisted screw insertion techniques using the Bernese optoelectronic guidance system. In the computer assisted group, nine patients were dropped, one because of an inadequate preoperative CT, seven because of problems with the specific instruments or the computer system, and one because of an anesthesiologic intraoperative complication. Thus, there were 50 patients in the conventional group (Group 1) and 41 patients in the computer assisted group (Group 2). There were no statistical differences between the groups concerning age, diagnosis and type of operation performed. Screw positions were verified postoperatively by an independent radiologist using a sophisticated CT protocol. There were 277 screws in Group I (T8 – S1), and 219 in Group 2 (T9 –S1). No statistical differences between the groups were found concerning mean operating time, blood loss or number of screws per patient. The pedicle perforation rate was 13.4 % in Group 1, and 4.6 % in Group 2 (p=0.006). The majority of perforations were less than 4 mm. Pedicle perforations of more than 4 mm were found in 4/277 (1.4%) screws in Group 1 but none in Group 2. Complications, not related to pedicle screws, were two L5 nerve root lesions, one major intraoperative bleeding, one endplate fracture and one postoperative, death in Group 1. In Group 2, one patient had deep wound infection. In conclusion, transpedicular screws could be inserted more accurately with image guidance than with conventional methods.

** The FDA has not cleared a drug and/or medical device for the use described in this presentation. (i.e., the drug or medical device is being discussed in an “off–label: use).