Klippel-Feil syndrome in congenital scoliosis

Study design Retrospective review. Objective To investigate the clinical manifestations and radiological characteristics of Klippel-Feil syndrome (KFS) in congenital scoliosis (CS). To identify the incidence of spinal or extraspinal abnormities in KFS. Summary of background data KFS is an uncommon condition, characterized as improper segmentation of one or more cervical spine segments. "Scoliosis" is potentially the most common manifestation associated with KFS. However, the clinical manifestations and radiological characteristics of KFS in patients with CS are less reported. Methods A total of 516 patients with CS from January 2009 to March 2013 were identified from a single institution. The demographic distribution and clinical and radiographical data were collected. Cervical regions were also designated as high (O-C2), mid (C2-C4), and low (C4-T1). The incidence of intra- and extraspinal abnormalities associated with KFS was investigated. Results In total, 28 patients (5.42%) had been identified with KFS, which included 8 males and 20 females. The mean coronal cervical alignment was 20.6° and sagittal alignment was 29.9°. KFS type I was found in 14 patients (50.0%), type II in 6 (21.4%), and type III in 8 (28.6%). Congenitally fused cervical segment is more common in the mid and lower cervical spine region (85.7%, 24/28). In the 28 patients with KFS, 11 have intraspinal anomalies (32.1%) and 6 have extraskeletal anomalies (21.4%). Thirteen patients (46.4%) exhibited rib anomalies. The incidence of rib anomalies showed no significant difference in CS patients with KFS and without KFS (P>0.05). A half of the patients with KFS have hemivertebrae; however, the incidence of hemivertebrae showed no significant difference in CS patients with KFS and without KFS (P>0.05). Conclusion The incidence of KFS was 5.42% in patients with CS. Congenitally fused cervical patterns are more common in the mid and lower cervical spine region. The incidence of rib anomalies, intraspinal abnormities, and hemivertebra was not increased in CS patients with KFS. Level of evidence 4.