Vertebral Fracture Versus Degenerative Spine Disease: The Effect of Cervical Fusion Indication on Risk of Pseudarthrosis.

Abstract

Retrospective cohort study. To provide quantitative data regarding long-term complications of cervical fusion based on surgical indication. Pseudarthrosis, or failure to obtain solid bony fusion, is a potential complication of cervical fusion surgery responsible for 45%-56% of revisions. This study aims to determine whether the underlying indication for surgery influences the risk of non-union or revision. The TriNetX Research Network was queried for adults older than or equal to ≥18 years undergoing primary cervical fusion for fracture or degeneration. Cohorts were constructed for posterior (PCF) and anterior (ACF) fusion at C1-C7 levels, and fusions spanning cervicothoracic (CT) or occipitocervical (OC) junctions. Risk factors, demographic, and surgical variables were controlled by propensity matching. Analysis examined pseudarthrosis risk at 1-5 years and revision within 5 years after surgery. There were 2009 patients each in the matched PCF cohorts and 2077 in the matched ACF cohorts. In PCF cohorts, degenerative patients had higher pseudarthrosis risk (P<0.001; RR: 1.95, 95% CI: 1.51-2.53) and revision rates (P<0.001; RR: 2.83, 95% CI: 1.88-4.28) compared with fracture patients. Similarly, degenerative patients showed increased pseudarthrosis risk (P=0.001; RR: 1.52, 95% CI: 1.18-1.97) and revision rates (P=0.001; RR: 2.29, 95% CI: 1.37-3.80) in ACF cohorts. CT cohorts each included 4300 patients, whereas OC cohorts included 725 patients each. Pseudarthrosis risk was higher in degenerative CT (P<0.001; RR: 2.39, 95% CI: 1.97-2.90) and OC cohorts (P=0.008; RR: 1.67, 95% CI: 1.14-2.45). Revision risk was greater in degenerative OC patients (P=0.014; RR: 2.06, 95% CI: 1.15-3.71), but no significant association was found in CT patients (P=0.15). These results indicate that degenerative disease is associated with a higher risk of pseudarthrosis and revision after cervical fusion than is vertebral fracture. We hypothesize that the pathophysiology of degenerative disease may influence bone formation. Level 3-non-randomized, controlled cohort study.