Introduction: Innovation in implant design for anterior cervical discectomy has led to zero-profile devices, which lower the risk of dysphagia. However, less is known about postoperative outcomes. This study compares a large series of patients treated with zero-profile devices to a matched cohort with cage-plate implants.
Methods: Patients treated with a zero-profile interbody device (ACDF-Z) for 1-4 level ACDF, from 2013 to 2018, were retrospectively compared to those treated with a cage-plate device (ACDF-P), from 2008 to 2013, by a single surgeon. Fusion rates for patients who had a minimum 1-year follow-up, excluding those with additional hardware or insufficient imaging for fusion assessment, were evaluated via flexion-extension X-ray images or CT scans. Complications like subsidence, symptomatic pseudarthrosis (SP), and adjacent segment disease (ASD) rates were also recorded.
Results: Ninety-four patients underwent ACDF-Z with an average follow-up of 2.5 years (range 1-7) and 92 ACDF-P had an average of 4.8 years follow-up (range 1-12) (p=0.001). Overall fusion rates at the latest available follow-up were 85% by patient and 90% by level, which were similar for both groups. A more in-depth analysis evaluated single-level fusion rates (ACDF-Z=93% vs ACDF-P=88%, p=0.49) and multilevel fusion rates by patient between the 2 groups (ACDF-Z=80% vs ACDF-P=82%, p=1.00). Subsidence was reported more frequently in the ACDF-Z group, but was not statistically significant (ACDF-Z=10% vs ACDF-P=3%, p=0.13). Reoperation for SP (ACDF-P=12% vs ACDF-Z=3%) and ASD (ACDF-P=15% vs ACDF-Z=7%, p=0.11) occurred more often after ACDF-P, but were not statistically different between the 2 groups.
Conclusion : Both ACDF-Z and ACDF-P cohorts demonstrated similar fusion rates in this large, single-surgeon study with minimum one-year follow-up. Additionally, there was no significant differences between ACDF-Z and ACDF-P groups when comparing for subsidence, symptomatic pseudarthrosis, and adjacent segment disease rates.
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