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Updated: May 29, 2026
Multilevel Oblique Lumbar Interbody Fusion in Degenerative Lumbar Disc Disease with Instability
Published on: July 25, 2025
Comparison of 1-Level to 2-Level Cervical Disc Arthroplasty: A Network Meta-Analysis of Adjacent Segment Disease and
Kern H Guppy1,2, Muhammad Sulman3, Haiden M Guppy4
1Department of Neurological Surgery, University of California, Davis, CA.
Study Design:
Systematic review with network meta-analysis (NMA).
Objective:
To determine if there is a difference in adjacent segment disease (ASD) and all-cause reoperations between 1-level and contiguous 2-level cervical disc arthroplasty (CDA1, CDA2).
Summary Of Background Data:
There are conflicting results from previous studies that there is a difference in reoperations between CDA1 and CDA2 possibly reflecting undertreatment of adjacent cervical degenerative disc disease with its natural history in CDA1.
Methods:
We conducted a random-effects NMA with only FDA Investigational Device Exemption (IDE) studies and international randomized controlled trials (RCTs) with more than 5 years of follow-up. Direct comparisons included CDA1 versus 1-level anterior cervical discectomy with fusion (ACDF1), CDA2 versus 2-level ACDF (ACDF2), and ACDF2 versus ACDF1; together, these formed a connected network in which ACDF served as the anchoring comparator, enabling anchored indirect comparisons between CDA1 and CDA2. Binary outcomes (ASD and all-cause reoperations) were analyzed using odds ratios within a frequentist framework in Stata.
Results:
NMA for ASD reoperations had 13 studies directly comparing CDA1 vs ACDF1 (n=4,135), 2 studies comparing 2-level CDA2 vs ACDF2 (n=789), and 1 study comparing ACDF2 vs ACDF1 (n=207). Results demonstrated no significant difference in ASD reoperation (OR 0.98, 95% CI 0.38-2.54) for CDA1 versus CDA2. For all-cause reoperations there were 14 studies directly comparing CDA1 vs ACDF1 (n=4,246), 2 studies comparing CDA2 vs ACDF2 (n=837), and 1 study comparing ACDF2 vs ACDF1 (n=223). CDA1 versus CDA2, demonstrated no significant difference in all-cause reoperation (OR 0.98, 95% CI 0.40-2.39).
Conclusions:
In our comprehensive NMA of selected FDA IDE studies and international RCTs with long-term follow-up, we found no significant difference between 1-level CDA and 2-level CDA with respect to ASD and all-cause reoperations. Future research is needed to see if our results are replicated in real world data.
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