[Surgical outcomes and prognostic analysis of congenital cervicothoracic scoliosis with Klippel-Feil syndrome].

<b>Objective:</b> To investigate the surgical outcomes of congenital cervicothoracic scoliosis (CTS) patients with Klippel-Feil syndrome (KFS) and prognostic characteristics across different subtypes. <b>Methods:</b> A retrospective case series study is conducted. Clinical and radiographic data of 41 CTS patients with KFS who underwent hemivertebra resection with instrumentation at Department of Orthopedic Surgery, Nanjing Drum Tower Hospital from March 2012 to September 2022, with a minimum follow-up of two years, were analyzed. The cohort included 16 males and 25 females, aged (8.6±3.7) years (range: 3 to 15 years). Preoperative, immediate postoperative, and final follow-up cervicothoracic deformity parameters were compared. Patients were classified into three subtypes based on preoperative coronal alignment: shoulder-neck type (type A, 16 cases), trunk-tilt type (type B, 16 cases), and thoracic compensatory curve type (type C, 9 cases). The severity of KFS and the incidence of distal curve progression among subtypes were analyzed. Repeated measurement data were compared by repeated measurement ANOVA, pairwise comparison within groups was performed by Bonferroni method, and categorical variables were compared by Chi-square test or Fisher exact probability method. <b>Results:</b> All patients underwent successful surgery. Twenty-one patients (53.7%) had cervical fusion of ≥3 segments, and 63.1% (82/130) of fused cervical segments were located proximally to the instrumentation. Postoperative cervicothoracic Cobb angle, head tilt, head shift, neck tilt, and clavicle angle significantly improved (all <i>P</i><0.05). The proportion of patients with cervical fusion of ≥3 segments was higher in types B and C (17/25) than that in type A (5/16) (<i>χ</i>²=5.299, <i>P</i>=0.021). Four type B (4/16) and 5 type C (5/9) patients underwent long-segment fixation, with stable coronal alignment postoperatively. The remaining patients received short-segment fixation. In the short-segment group, the incidence of distal curve progression was significantly higher in types B and C (8/16) than that in type A (1/16) (<i>P</i>=0.015). Ultimately, 3 type B patients underwent revision surgery, and 1 type C patient met the criteria for revision (distal compensatory thoracic or lumbar curve>40°). <b>Conclusions:</b> CTS patients with KFS are predisposed to develop significant coronal malalignment involving trunk tilt (type B) or thoracic compensatory curve (type C) before surgery. Following hemivertebra resection with short-segment fixation, such patients have a high risk of distal curve progression and potential need for revision surgery.