Does coronal plane deformity matter for cervicothoracic kyphosis surgery? The incidence of cervical scoliosis and influence on the outcomes of cervical deformity surgery

BACKGROUND CONTEXT: Cervical deformity (CD) patients may have both cervical kyphosis (CK) and coronal plane cervical deformity, ie, cervical scoliosis (CS). Although the deformity with the greatest influence on the clinical outcomes is CK, few studies have focused on the complex condition of combined CK and CS and significance of CS in the correction of CD. PURPOSE: This study sought to investigate 1) the incidence of combined CS/CK from a CD cohort underwent corrective surgery, 2) whether CK patients combined CS required more aggressive treatment and 3) had different preoperative and postoperative clinical outcomes compared to the CK only group. STUDY DESIGN/SETTING: This is a retrospective review of a prospective, multicenter CD database. PATIENT SAMPLE: Patients undergoing surgery for CD with cervical kyphosis (defined as C2-C7 (CL) > 10° kyphosis or C2-C7 sagittal vertical axis (SVA) > 4cm) were included. Patients with lumbar scoliosis > 10° were excluded. OUTCOME MEASURES: CS was defined as C2-C7 coronal Cobb angle as ≥ 10°. METHODS: We compared surgical factors, preoperative PROs as well as preoperative and follow-up radiographic data. Chi Square, Fisher's Exact, and Wilcoxon-Mann-Whitney, and T-tests were utilized, as appropriate. Statistical significance was considered p<0.05. RESULTS: A total of 100 operative patients with cervical kyphosis were included (mean age 61.2 years, 51.5% female). Twelve patients (12.0%) had combined CS with CK (CS/CK group) and 88 patients (88%) had CK only (CK group). Preoperative maximum cervical coronal Cobb angle was 3.7° in the CK group and 17.1° in the CS/CK group. In the CS/CK group, this value improved to 10.1° (p<0.0001), but CS > 10° was still present in 3 patients, with a mean correction percentage of 47.1% of initial scoliosis. Mean sagittal plane correction in the CK vs CK/CS group was +7.6° vs +14.9° (p=0.54) in CL, -12.2mm vs -7.4mm in C2-C7 SVA (p=0.33), -13.9° vs -11.1° in T1 slope (TS)-CL (p=0.73), -0.4° vs -1.6° in thoracic kyphosis (TK)(p=0.57). The CK group had 13.8% anterior, 52.9% posterior, 33.3% anterior-posterior surgery, and the CS/CK group had 16.7% anterior, 41.7% posterior, and 41.7% anterior-posterior surgery (p=0.77). 55.7% in the CK group underwent any type of osteotomy, versus 58.3% in the CS/CK group (p=0.86). VCR or corpectomy was performed in 18.1% of the CK only group, and in 25.0% of the CS/CK group (p=0.69). For the CK vs CS/CK, the mean baseline NDI was 49.8 vs 44.8 (p=0.41), and 14.1 vs 15.2 for mJOA (p=0.16). CONCLUSIONS: Overall, 12.0% of CD patients also had combined cervical scoliosis. Postoperatively, the residual coronal plane deformity was >50% of the preoperative deformity in the CK/CS group. However, the radiographic and clinical outcomes, surgical procedures of the CK group and the CK/CS group did not demonstrate significant differences. The present study firstly provided the evidence that CK is the major component of CD and the correction of CK is the mainstay of corrective surgery of CD even combined with CS. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

Duke Scholars

Author Peter Passias Orthopaedic Surgery

Author Christopher Ignatius Shaffrey Orthopaedic Surgery