Examining autocorrection of concurrent cervical malalignment following thoracolumbar deformity surgery.

Abstract

The aim of the study was to assess preoperative radiographic parameters predictive of cervical deformity (CD) autocorrection in patients undergoing thoracolumbar deformity (ASD) surgery. This was a retrospective cohort study. Inclusion criteria were operative ASD patients with complete baseline (BL) and 2-year radiographic data. Patients with cervical fusion during index surgery, revision involving cervical fusion, and those who developed proximal junctional kyphosis by 2-year postoperative were excluded from the study. If patients met CD criteria at BL but not at 6 weeks or 2 years postoperatively, they were considered autocorrected (AC). Descriptive and univariate analysis, binominal logistic regression, and multivariable backward stepwise regression. Two hundred and twenty ASD patients were included. 51.4% of patients had preoperative CD. By 6-week postoperative, 32.7% achieved AC. At 2 years, 24.8% of preoperative CD patients obtained AC. 2-year AC patients had lower BL sacral slope, lumbar lordosis (LL), T1 slope, cervical lordosis (CL), and C2-T3, and T2-T12 kyphosis (all P < 0.05). Patients with BL-unmatched Roussouly types are corrected postoperatively and are more likely to experience autocorrection at 1 year (45.2% vs. 19.0%; P = 0.042) and at 2 years (31% vs. 4.8%; P = 0.018). Multivariable analysis revealed that patients with BL-mismatched Roussouly types were corrected postoperatively and showed a significant increase in likelihood of AC at 1 year (odds ratio [OR]: 18.72; P = 0.029) and 2 years (OR: 8.5; P = 0.047). Similarly, BL LL (OR: 0.772; P = 0.003) and CL (OR: 0.829; P = 0.005) exhibited significant predictive value for autocorrection at 1 year and 2 years (OR: 0.927; P = 0.004 | OR: 0.942; P = 0.039; respectively). Autocorrection is more likely in patients with postoperatively corrected Roussouly types, those with lower BL cervical, and LL. Given these findings, it may not be necessary to routinely extend reconstruction into the cervical spine for ASD patients with similar characteristics to those in this study.