Durability and Failure Mechanisms of Cervical Deformity Correction Surgery

Study DesignRetrospective cohort study.ObjectivesTo characterize longitudinal durability of cervical deformity (CD) correction, identify predictors of alignment failure, and define failure mechanism timing across the first postoperative year.Methodsof 155 operative CD patients in a prospectively maintained multicenter database, 89 had complete four-timepoint radiographic follow-up. Well-alignment was defined as cSVA <4 cm. Patients were grouped as A (maintained), B (corrected then deteriorated), or C (never aligned). Analyses included Cox regression (n=47, 17 events), Kaplan-Meier with restricted mean survival time (RMST), and mixed-effects logistic regression across four timepoints (n=356; ICC=0.36). Concurrent thoracolumbar deformity was excluded.ResultsWell-aligned proportion fell from 48.3% at 3 months to 33.7% at 1 year (A=34%, B=19%, C=47%). DJK was most strongly associated with alignment loss (HR 5.21, 95% CI 1.94-13.98; OR 0.09), with alignment maintained 4.1 versus 9.8 months (RMST difference 5.7, p=0.001). Lower postoperative cSVA paradoxically increased failure hazard (HR 0.58/10 mm, p=0.002). Older patients deteriorated faster (Time×Age OR 0.88, p=0.022). Failure mechanisms shifted from DJK at 3 months (50%) to PJK at 6 months (75%) to global compensation loss at 1 year (71%). No surgical parameters differed between groups.ConclusionsFewer than one-third of patients maintain alignment at 1 year. DJK, advanced age, and lower postoperative cSVA were most strongly associated with failure (17 events; limited precision). Mechanisms appeared to shift from junctional failure early to global decompensation late. Alignment loss was not accompanied by significant 1-year NDI or EQ-5D differences, framing radiographic deterioration as an early surveillance marker rather than clinical failure. Individualized risk stratification and surveillance are supported.