Positioning thoracic pedicle screw entry point using a new landmark: a study based on 3-dimensional computed tomographic scan.
METHODS
A novel method to identify the entry point.


OBJECTIVE
To quantify the position of thoracic pedicle screw entry points on the lamina at various segments of the thoracic vertebrae in normal subjects and patients with adolescent idiopathic scoliosis and propose a new technique to select entry points using a new landmark.


BACKGROUND
Thoracic pedicle screws have been widely used in thoracic surgery, and the placement of pedicle screws has been studied extensively. However, there are only qualitative studies on selecting the entry point, and no study has quantified the position of entry points.


METHODS
A retrospective study using 3-dimensional computed tomographic reconstruction techniques were used to study the morphology of thoracic vertebrae in 110 adolescents (56 cases of adolescent idiopathic scoliosis and 54 normal subjects). A quantitative area was used to select the entry point. Thoracic pedicle screw entry point was determined using the new landmark as reference and thoracic pedicle screws were placed in 21 patients. Postoperative computed tomographic scanning was performed to assess the safety and effectiveness of this entry point selection technique.


RESULTS
We determined that the accuracy of pedicle screw placing after positioning entry point using the quantitative area was significantly superior to that after positioning entry point using the traditional method (P < 0.05).


CONCLUSIONS
The new technique quantifies the position of each thoracic pedicle screw entry point and it is convenient, easy to operate, and has relatively high accuracy of screw placement. This positioning technique can provide safe and accurate clinical guidance for selecting thoracic pedicle screw entry point.
From the Department of Orthopaedics, Chinese People's Liberation Army General Hospital, Beijing, PR China.
Deng-bin
DB
Qi
Jing-ming
JM
Wang
Yong-gang
YG
Zhang
Guo-quan
GQ
Zheng
Xue-song
XS
Zhang
Yan
Y
Wang
D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D019637:Orthopedic Procedures / Q000295:instrumentation* / Q000379:methods; D065289:Pedicle Screws; D015203:Reproducibility of Results; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods