ABSTRACT

Procedures about spinal surgery are generally stili performed with conventional techniques using anatomical landmarks due to high costs, long operating processes and difficult techniques of navigation systems used for spinal instrumentation. Although it is checked if there is a perforation inside the canal opened through the pedicule by using probes, penetrations through the corpus and the pedicle inevitably occurs. The main objective of our study is to evaluate the accuracy of computerized tomography in early diagnosis of these penetrations and to take a view on deciding about when it is necessary to revise the application.

Pedicle screws were inserted through 200 pedicles of 40 patients who underwent surgery using the Funnel technique and the patients were assessed with computerized tomography scan in early post operative period.

In 18 pedicles, the screws were found penetrated. Twelve of them penetrated the lateral cortex of the pedicle and 6 of the screws penetrated the medial cortex of the pedicle. In 2 of the patients the penetrations were determined as critical and the patients were immediately reoperated. During surgery, we observed that the penetrations were critical as revealed by computerized tomography and the screws compressed on nerve roots. No neurovasculary deficit was present in the patients in whom the screw penetrations were determined as non-critical by computerized tomography scan. Twelve of the penetrations which were through the anterior cortex of the corpus and more than 5 mm deep were determined as non-critical. Two of the anterior penetrations deeper than 5 mm were determined as critical

In conclusion, computerized tomography scanning is a reliable assessment in the early diagnosis of penetrations and critical /non-critical classification for spinal instrumentation.