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The Importance of the Pedicle Diameters at the Proximal Thoracic Vertebrae for the Correction of Proximal Thoracic Curve in Asian Patients With Idiopathic Scoliosis

Lee, Choon Sung, MD; Cho, Jae Hwan, MD; Hwang, Chang Ju, MD; Lee, Dong-Ho, MD; Park, Jae-Woo, MD; Park, Kun-Bo, MD

doi: 10.1097/BRS.0000000000002926

Study Design. A retrospective comparative radiographic study.

Objective. The purpose of this study was to evaluate differences in the pedicle diameters of proximal thoracic vertebrae in relation to the severity of the proximal thoracic curve in Asian patients with idiopathic scoliosis.

Summary of Background Data. A small pedicle diameter at the proximal thoracic vertebra has been reported in normal population, but the changes of pedicle diameter in patients with a proximal thoracic curve have not been properly evaluated.

Methods. One hundred eighty-two patients with adolescent idiopathic scoliosis involving a greater than 10-degree proximal thoracic curve were analyzed. Sixty-nine and 113 patients had a structural and nonstructural proximal thoracic curve, respectively. The pedicle width was evaluated from T1 to T4 using a reconstructed computed tomography (CT) scan. The pedicle widths were compared between the convex and concave side, and between the structural and nonstructural proximal thoracic curve groups.

Results. The pedicle widths at T3 (0.76 ± 0.92 mm) and T4 (0.50 ± 0.69 mm) on the concave side for the structural proximal thoracic curves were extremely narrow compared with those for the nonstructural proximal thoracic curves (T3,1.17 ± 0.84 mm; T4,0.82 ± 0.72 mm) (P = 0.002, 0.003, respectively). However, the T2 pedicle width was comparable on the concave side in both groups (2.44 ± 0.94 mm for the nonstructural and 2.32 ± 0.97 mm for the structural proximal thoracic curve, P = 0.430).

Conclusion. A pedicle screw insertion at the T3 or T4 vertebra on the concave side is not always possible in cases of a structural proximal thoracic curve; however, the pedicle width of the T2 vertebra is very wide and safe for the standard pedicle screw insertion. These results should be considered when the surgeon decides the upper instrumented vertebra or the correction method for the structural proximal thoracic curve.

Level of Evidence: 3

In patients with the structural thoracic curve, the narrow pedicle diameter of T3 and T4 on the concave side and the wide pedicle diameter of T2 should be considered during the decision of upper instrumented vertebra and correction method.

Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Address correspondence and reprint requests to Kun-Bo Park, MD, Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, PungNap 2-Dong, SongPa-gu, Seoul 05505, Korea; E-mail:

Received 17 August, 2018

Revised 25 September, 2018

Accepted 11 October, 2018

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

No relevant financial activities outside the submitted work.

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.