Object: The authors evaluated the effectiveness of Lenke Type 2 criteria in scoliosis correction with the segmental pedicle screw (PS) technique, with emphasis on shoulder balance.
Methods: Twenty-five consecutive patients with Lenke Type 2 scoliosis (structural double thoracic curves, sidebending Cobb angle > 25 degrees , or T2-5 kyphosis > 20 degrees ) who underwent segmental PS instrumentation were included in this study. At surgery, the patients were an average of 14.1 years of age, and the average duration of follow-up was 2.9 years. For radiological evaluation of the patients, preoperative, postoperative, and the latest available follow-up radiographs were used. The difference between right and left shoulder heights was determined to assess shoulder balance. All patients were treated with fusion of both the proximal and distal curves.
Results: The mean preoperative proximal thoracic curve of 43 degrees was corrected to 21 degrees postoperatively, a 51.2% correction. The preoperative lower thoracic curve of 61 degrees was corrected to 23 degrees , for a 62.3% correction. The preoperative shoulder height difference of -5.92 +/- 12.52 mm (range: -31 to +14 mm, negative designating a lower left shoulder) was improved to 1.52 +/- 8.12 mm. Postoperatively, no patient had significant or moderate shoulder imbalance, 4 patients had minimal shoulder imbalance, and 21 patients had balanced shoulders.
Conclusions: Although Lenke Type 2 criteria were developed wth Cotrel-Dubousset instrumentation, they are successfully applied to determining thoracic fusion when segmental PS instrumentation is used.