Reoperation risks between 1-level and 2-level cervical disc arthroplasty: analysis of a cohort of patients from a national spine registry.

Authors

David J Moller, Richard N Chang, Haiden M Guppy, Ellie Moller, Heather A Prentice, Jessica E Harris, Shayan Rahman, Harsimran S Brara

Published in

Neurosurgical focus. Volume 61. Issue 1. Pages E3. Jul 01, 2026.

Abstract

The aim of this study was to determine if there is a difference in reoperations for adjacent segment disease (ASD) and all-cause reoperations between 1-level and contiguous 2-level cervical disc arthroplasty (CDA).
A retrospective cohort study was conducted on patients (18-60 years of age) with cervical degenerative disc disease who underwent a primary 1-level or 2-level CDA using data from a national spine registry. Cox proportional hazards regression was used to evaluate reoperations for all-cause risks. Hazard ratios (HRs) and 95% confidence intervals are presented; a p value < 0.05 was the significance threshold.
The cohort consisted of 650 patients with 1-level CDA and 159 patients with 2-level CDA. The mean overall observational follow-up was 6.2 years (SD 4.3 years) for 1-level CDA and 4.2 years (SD 3.1 years) for 2-level CDA. The 5-year incidence of ASD reoperations was higher in 1-level CDA (4.7%, 95% CI 2.8%-6.6%) compared to 2-level CDA (1.1%, 95% CI 0.0%-3.15%). In Cox regression analysis, there was no statistical difference in all-cause reoperations between 1-level CDA and 2-level CDA (HR 0.93, 95% CI 0.44-1.94; p = 0.84). Few events in 2-level ASD reoperations allowed determination of hazard ratio.
This study is the first large real-world analysis outside of investigational device exemption trials to show no significant difference in all-cause reoperation rates between 1-level and 2-level CDA. Notably, the 5-year incidence of ASD-related reoperations was substantially higher following 1-level CDA compared with 2-level CDA. The reason for this discrepancy remains unclear. One possibility is surgeon selection bias-where an adjacent degenerative level may be left untreated during a 1-level CDA under the assumption that motion preservation would protect against adjacent segment deterioration. Alternatively, the higher ASD rate may simply reflect the natural history of cervical spondylosis rather than device effect. Further investigation is needed to determine the true drivers of this observation.

PMID:
42385245
Bibliographic data and abstract were imported from PubMed on 02 Jul 2026.

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