Accuracy of Pedicle Screw Placement in Thoracic Spine Fractures

Abstract

Background and Purpose:

Accuracy of pedicle screw placement is essential for stabilization of spinal fractures and their outcome. A scoring system was developed to facilitate determination of pedicle screw placement and decision of pedicle screw revision. The aim of this study is to evaluate the inter- and intraobserver reliability of the presented scoring system in a multicenter study.

Material and Methods:

Postoperative computed tomography (CT) scans of 30 thoracic pedicle screws were reviewed by 50 observers in 14 hospitals experienced in spinal trauma. Pedicle screws of the universal spine system were used for dorsal stabilization of traumatic thoracic spine fractures (T1–T10). Placement of pedicle screws was scored from grade I to grade III. A compact disk was sent to each hospital including a detailed description of the scoring system. The score of each pedicle screw, its need for revision with or without postoperatively coexisting neurology of the patient had to be marked on a record. The investigation of the intraobserver reliability followed with a 2-month interval using the same set of postoperative CT scans but in another sequence. Statistics: Cohen’s κ-test.

Results:

Inter- and intraobserver reliability was substantial with a mean κ-coefficient of 0.70 (confidence interval 0.66–0.73; p < 0.0005) and 0.71 (confidence interval 0.68–0.75; p < 0.0005), respectively. Mean interobserver agreement for each grade of pedicle screws was 74.9%, and 73.7% for the intraobserver agreement. Revision of pedicle screws was suggested for grade III screws with or without appearance of neurologic symptoms, whereas revision was additionally recommended for grade IIb screws when neurologic deterioration occurred postoperatively.

Conclusion:

The inter- and intraobserver reliability of the presented scoring system was substantial. The scoring system is an appropriate tool for determination of accuracy of pedicle screw placement. The scoring system may be helpful in terms of a better comparability of different studies and the decision on pedicle screw revision.