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Prediction of Spontaneous Lumbar Curve Correction After Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis Lenke Type 1 Curves

Uehara, Masashi, MD*; Takahashi, Jun, MD*; Ikegami, Shota, MD*; Kuraishi, Shugo, MD*; Futatsugi, Toshimasa, MD*; Oba, Hiroki, MD*; Takizawa, Takashi, MD*; Munakata, Ryo, MD*; Koseki, Michihiko, PhD; Kato, Hiroyuki, MD*

doi: 10.1097/BSD.0000000000000736
PRIMARY RESEARCH
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Study Design: This is a retrospective single-center and single-surgeon study.

Objective: The present study examined for preoperative parameters having the highest correlation with compensatory thoracolumbar/lumbar (TL/L) curve correction 2 years after surgery in adolescent idiopathic scoliosis (AIS) patients with Lenke type 1 curves.

Summary of Background: Several parameters have been considered to evaluate the flexibility of compensatory TL/L curve in AIS patients with Lenke type 1 curves. However, the imaging position with the strongest correlation with postoperative spontaneous TL/L curve correction is unknown.

Data: In total, 37 patients with AIS Lenke type 1 curves who had undergone skip pedicle screw fixation were followed for a 2-year period were enrolled.

Materials and Methods: TL/L Cobb angles measured at the standing posteroanterior view, supine position, supine position with maximum bending, supine position with traction, prone position, and prone-push position were determined before surgery. Using TL/L Cobb angles determined 2 years postoperatively, correlations between preoperative and postoperative Cobb angles were calculated for each position using the Spearman rank-correlation coefficient, linear regression analysis, and paired t tests.

Results: Mean preoperative mean±SD TL/L Cobb angle was significantly improved from 31±9 to 13±8 degrees at the study end point. In analyses of correlations between postoperative TL/L Cobb angle and preoperative parameters, the supine position with traction was most strongly associated with TL/L curve correction rate at 2 years after surgery (r=0.72; P<0.01), with paired t tests revealing a significant mean difference of 3.1 degrees.

Conclusions: Preoperative Cobb angle evaluated at the supine position with traction had the strongest correlation with spontaneously corrected TL/L curve Cobb angle after selective thoracic fusion for AIS Lenke type 1 curves. Accordingly, it may be sufficient to evaluate TL/L curve correction at this position only to reduce radiation exposure and operative time.

*Department of Orthopaedic Surgery, Shinshu University School of Medicine, Asahi, Matsumoto

Faculty of Textile Science and Technology, Shinshu University, Tokida, Ueda, Nagano, Japan

The authors declare no conflict of interest.

Reprints: Jun Takahashi, MD, Department of Orthpaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan (e-mail: jtaka@shinshu-u.ac.jp).

Received April 9, 2018

Accepted October 1, 2018

© 2019 by Lippincott Williams & Wilkins, Inc.