Spontaneous correction of coronal imbalance after selective thoracolumbar/lumbar fusion in patients with lenke-5c adolescent idiopathic scoliosis

Publication date: Available online 22 March 2018
Source:The Spine Journal
Author(s): Chang Ju Hwang, Choon Sung Lee, Hyojune Kim, Dong-Ho Lee, Jae Hwan Cho
Background ContextCoronal imbalance is a complication of corrective surgeries in AIS. However, few studies about immediate coronal decompensation in Lenke-5C curves have reported its incidence, prognosis, and related factors.PurposeTo evaluate the development of coronal imbalance after selective thoracolumbar/lumbar (TL/L) fusion (SLF) in Lenke-5C adolescent idiopathic scoliosis (AIS), and to reveal related factors.Study Design/SettingRetrospective comparative study.Patient SampleThis study included 50 consecutive patients with Lenke-5C AIS who underwent SLF at a single centerOutcome MeasuresWhole-spine anteroposterior and lateral radiographs were used to measure radiological parameters.MethodsPatients were divided into 2 groups according to the presence/absence of coronal imbalance (distance between C7 plumb line and central sacral vertical line >2 cm) in the early (1 month) postoperative period. Various radiological parameters were statistically compared between groups.ResultsOf the patients, 28% (14/50) showed coronal imbalance in the early postoperative period; however, most of them (13/14) showed spontaneous correction during follow-up. The development of coronal imbalance was related to less flexibility of the TL/L curve (51.3% vs. 52.6%, P=0.040), greater T10-L2 kyphosis (11.7° vs. 6.4°, P=0.034), and greater distal junctional angle (6.0° vs. 3.7°, P=0.025) in preoperative radiographs. Lowermost instrumented vertebra (LIV) tilt was greater in the decompensation [+] group in the early postoperative period (8.8° vs. 4.4°, P=0.009). However, this difference disappeared in final follow-up with the decrease of LIV tilt in the decompensation [+] group.ConclusionsLess flexibility of the TL/L curve, greater TL kyphosis, and greater distal junctional angle preoperatively were predictive factors for immediate coronal imbalance in Lenke-5C curves. Although coronal imbalance was frequently detected in the early postoperative period after SLF, it was mostly corrected spontaneously with a decrease of LIV tilt. Thus, SLF for Lenke-5C curves can be a good option regardless of the possible coronal imbalance in the early postoperative period.



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