The Effect of Subsidence on Segmental and Global Lordosis at Long-term Follow-up After Anterior Cervical Discectomy and Fusion

Abstract

Objective: Subsidence following anterior cervical discectomy and fusion (ACDF) may lead to disruptions of cervical alignment and lordosis. The purpose of this study was to evaluate the effect of subsidence on segmental, regional, and global lordosis.Methods: This was a retrospective cohort study performed between 2016–2021 at a single institution. All measurements were performed using lateral cervical radiographs at the immediate postoperative period and at final follow-up greater than 6 months after surgery. Associations between subsidence and segmental lordosis, total fused lordosis, C2–7 lordosis, and cervical sagittal vertical alignment change were determined using Pearson correlation and multivariate logistic regression analyses.Results: One hundred thirty-one patients and 244 levels were included in the study. There were 41 one-level fusions, 67 two-level fusions, and 23 three-level fusions. The median follow-up time was 366 days (interquartile range, 239–566 days). Segmental subsidence was significantly negatively associated with segmental lordosis change in the Pearson (r = -0.154, p = 0.016) and multivariate analyses (beta = -3.78; 95% confidence interval, -7.15 to -0.42; p = 0.028) but no associations between segmental or total fused subsidence and any other measures of cervical alignment were observed.Conclusion: We found that subsidence is associated with segmental lordosis loss 6 months following ACDF. Surgeons should minimize subsidence to prevent long-term clinical symptoms associated with poor cervical alignment.

Safety and Efficacy of Zero-Profile Polyetheretherketone (PEEK) Cages Filled with Biphasic Calcium Phosphate (BCP) in Anterior Cervical Discectomy and Fusion (ACDF): A Case Series

“…These results highlight the relevance of addressing the best surgical practices in order to avoid subsidence. Even if the measurement of cervical and segmental lordosis was above the scope of this case series, this finding can be explained by the fact that subsidence after ACDF produce a loss of segmental lordosis [31]. Since a lower C2-C7 Cobb angle and kyphotic deformity are related with higher disability [10], the subgroup of patients which suffered from subsidence in our study may have reached a degree of loss of segmental lordosis which produced a worse pain and disability outcome.…”

Comparing zero-profile and conventional cage and plate in anterior cervical discectomy and fusion using finite-element modeling

“…However Zhe et al 15 revealed that the overall subsidence rate was higher in the ZPSC implants than in the CCP implants (66.67% vs 38.46%, p = 0.006). In a meta-analysis conducted by Yingjje 35 ZPSC implants had a higher incidence of postoperative subsidence than that in the CCP implants (15.1% vs 8.8%, p = 0.0005). Our study confirmed prior findings that using a ZPSC implant without a plate leads to a higher subsidence rate, interfering with disc stability and potentially incurring a higher reoperation rate 5 , 36 , 37 .…”

Clinical Effectiveness of Artificial Disc Replacement in Comparison With Anterior Cervical Discectomy and Fusion in the Patients With Cervical Myelopathy: Systematic Review and Meta-analysis

“…However, more proper patient selection and technical modifications such as over-milling of the endplate’s avoidance enabled the Bryan prosthesis to overcome this default [ 40 ]. Even ACDF also has the concerns of segmental kyphotic change, further leading to worse clinical outcomes, associated with subsidence of intervertebral cages [ 41 ].…”