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| Comparison of CT and direct visualization in thoracic pedicle screw placement |
| SONG Zhi-ming, LIU Yi, YAO Di, WANG Shu-qing, CHEN Liang |
| Department of Orthopeadics, the First Hospital of Jilin University, Changchun 130021, China |
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Abstract Objective: To get the information of the ability of CT scanning as a tool to assess the accuracy of thoracic pedicle screw placement. Methods: Pedicle screws were inserted in five cadaveric spines. Speciments were scanned by CT and three observer graded the appearance of the screw based on CT scans. The results were compared with those of direct visualization group. Results: The authors arrived at a Kapper value of 0.603. For pedicle screw of grade Ⅰ, CT had a positive predictive value of 32%, a negative predictive value of 88%, a sensitivity of 33% and a specificity of 87%. Whereas, for pedicle screw of grade Ⅱ, CT had a positive predictive value of 60%, a negative predictive value of 100%, a sensitivity of 100% and a specificity of 88%. Conclusion: The authors conclude that CT scanning is a valid tool to assess the accuracy of thoracic pedicle screw placement, but in evaluating whether the screw has invaded the inner wall of the pedicle and its degree of invasion there has still some limitations.
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Received: 30 August 2005
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2006, Vol. 17 
