Late complication of cervical disc arthroplasty: heterotopic ossification causing myelopathy after 10 years. Illustrative case

Effect of fusion and arthroplasty for cervical degenerative disc disease in patients with physically demanding occupations

Background

Cervical degenerative disc disease (DDD) significantly affects the quality of life in labor-intensive careers. When conservative measures fail, either anterior cervical discectomy and fusion (ACDF) or cervical disc arthroplasty (CDA) may be indicated. Although ACDF is the gold standard, it can limit motion, whereas CDA preserves motion and may reduce adjacent segment disease (ASD). Few studies compare these surgeries in physically demanding populations, and the influence of workers' compensation (WC) on outcomes is unclear. Therefore, the purpose of this study is to compare the outcomes of CDA versus ACDF in patients with labor-intensive jobs and to assess how workers' compensation (WC) status influences these outcomes.

Methods

In this prospective cohort study, 300 (CDA: 150, ACDF: 150) patients with 1- or 2-level cervical DDD with labor-intensive jobs were enrolled, including a subgroup of 60 WC patients (CDA: 30, ACDF: 30). Participants were followed for a minimum of 2 years. Data collected included demographic details, perioperative events, and complication rates. Functional outcomes were measured using the Visual Analog Scale for neck and arm pain (VAS-neck, VAS-arm) and the Neck Disability Index (NDI), with attention to timelines for returning to full-time work.

Results

CDA patients returned to full-time work faster (4.3 vs 6.7 months, p=.025). More CDA patients resumed work by 6 weeks (p=.018) and 3 months (p=.022), though these differences waned by 6 months. WC patients had slower returns overall (CDA WC: 7.5 vs 5.0 weeks for non-WC, p=.015). CDA showed greater NDI improvement at all time points and significantly lower ASD incidence (1.3% vs. 26.7%, p<.001). Complications were comparable.

Conclusion

CDA may facilitate faster work return, better recovery, and lower ASD risk in labor-intensive patients. WC status correlates with delayed recovery, suggesting a need for tailored approaches. Further research is necessary to confirm these findings and refine patient selection.

Are Patients With Segmental Cervical Kyphosis Appropriate Candidates for Cervical Disc Arthroplasty (CDA)? A Clinical and Radiographic Analysis Compared to Anterior Cervical Discectomy and Fusion (ACDF)

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To compare the clinical and radiographic outcomes of Anterior Cervical Discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) in patients with preoperative segmental kyphosis.

METHODS

Patients with segmental cervical kyphosis at the operative levels undergoing 1- or 2-level ACDF or CDA from 2017 to 2020 with 2 years of follow were identified. Patient demographics, perioperative data, complication rates, radiographic findings and reported outcomes were analyzed.

RESULTS

A total of 48 patients met inclusion criteria and were included in our study (ACDF: n = 24, CDA: n = 24). Patient demographic data between the 2 cohorts was similar expect for proportion of males (ACDF: 62.5% vs CDA: 33.3%, P = .043). There was no statistical significance in the change of segmental lordosis (ACDF: +8.09° vs CDA: +5.88°, P = .075) between the preoperative and final postoperative period. Additionally, the change in cervical lordosis was similar between groups (ACDF:+ 9.86° vs CDA: +7.60°, P = .226). VAS scores were similar between the 2 groups at every follow-up interval. NDI scores were significantly different at the 6-month, 12 month and the final follow-up. Mean improvements between preoperative and final postoperative periods were statistically superior in the CDA cohort compared to the ACDF cohort (ACDF: 22.8 vs CDA: 24.1, P = .0375).

CONCLUSION

CDA was superior to ACDF in regards to NDI scores following index procedure in patients with preoperative segmental cervical kyphosis. Those in the CDA cohort had similar complication rates, revision rates and radiographic outcomes as those who underwent ACDF.

Incidence and Risk Factor of Implant Dislocation After Cervical Disk Arthroplasty: A Retrospective Cohort Analysis of 756 Patients

BACKGROUND

Implant dislocation after cervical disk arthroplasty (CDA) is obviously a critical complication, but no information about the incidence and associated risk factor has been reported.

OBJECTIVE

To investigate the incidence and risk factor of implant dislocation after CDA by a retrospective cohort analysis.

METHODS

A retrospective review of a consecutive series of CDA performed between January 2009 and March 2021 at a single institution was conducted. Analyses of chart records and radiological data established the incidence and associated risk factor of implant dislocation after CDA. A Kaplan-Meier survival estimation of implant survival was performed.

RESULTS

A total of 756 consecutive patients were included in this analysis. Five patients (0.7%) had a migration and even dropout of the artificial disk. The overall cumulative survival rate of the implant reached approximately 99.3% of the 756 patients. Preoperative kyphosis was significantly related to implant dislocation ( P = .016), with an odds ratio of 15.013.

CONCLUSION

The incidence of implant dislocation after CDA is as low as 0.7% or 5/756 patients. Preoperative kyphosis significantly increases the risk of postoperative implant dislocation by a factor of 15. The migrating implants could be revealed on radiographs as early as 0.9 to 1.4 months postoperatively and were revised to anterior cervical diskectomy and fusion within half a year. No new event of implant dislocation occurred half a year postoperatively. The overall cumulative survival rate of the implant reached 99.3% of the 756 patients. In conclusion, CDA remains a safe and reliable procedure.