New-onset depression following anterior cervical discectomy and fusion or cervical artificial disc replacement: a retrospective cohort study using a multi-institutional claims database

Psychological outcomes after cervical spine surgery remain underexplored, particularly the development of new-onset depression. This study aimed to compare the long-term incidence of new-onset depression following anterior cervical discectomy and fusion (ACDF) versus cervical artificial disc replacement (ADR), hypothesizing that motion preservation with ADR may be associated with a lower risk of postoperative depression.

We conducted a retrospective cohort study using the TriNetX Global Collaborative Network, including patients who underwent ACDF or ADR between 2005 and 2020. Patients with pre-existing mood disorders or prior antidepressant use were excluded. A 1:1 propensity score matching was performed based on demographics and baseline comorbidities. New-onset depression was identified using ICD-10 diagnoses and/or antidepressant prescriptions. Time-to-event analyses were conducted using Kaplan–Meier curves, and hazard ratios (HRs), absolute risk differences, and numbers needed to treat (NNTs) were calculated.

At 5-year follow-up, ADR was associated with a significantly lower incidence of new-onset depression compared with ACDF (HR, 0.79; 95% CI, 0.72–0.87). The absolute risk difference was − 5.2%, corresponding to an NNT of 19. Consistent results were observed across alternative depression definitions.

In this large real-world cohort, ADR was associated with a modest but clinically meaningful reduction in the risk of new-onset depression compared with ACDF. These findings are hypothesis-generating and should be interpreted with caution given the observational design and the potential for residual confounding. Further prospective studies incorporating patient-reported outcomes are warranted.