ProDisc-C versus fusion with Cervios chronOS prosthesis in cervical degenerative disc disease: Is there a difference at 12 months?

Anterior cervical discectomy and fusion without plate (ACDFWP) versus anterior cervical disc arthroplasty (ACDA) for cervical spondylosis: A meta-analysis and literature review

This meta-analysis compared the clinical outcomes between two alternative surgeries for patients with cervical spondylosis, namely anterior cervical discectomy and fusion (ACDF) without plate (ACDFWP) vs. anterior cervical disc arthroplasty (ACDA). We searched databases, including PubMed, EMBASE, Cochrane Library, Google Scholar, and Web of Science (firstly available-2019). A standard meta-analysis was performed with the included studies. A Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool was used for the evaluation of the study quality of nonrandomized-controlled trials (nRCTs), while a Risk of Bias (RoB) battery was used for randomized controlled trials (RCTs). Eight studies involving 640 patients were included. No significant difference was found in the indices of Neck Disability Index (NDI) score, Visual Analog Score (VAS), Japanese Orthopaedic Association (JOA) score, operative time, blood loss, Swallowing Quality of Life Score (SWAL-QL), and complications. Cervical alignment was significantly better in the ACDFWP than in ACDA (mean difference (MD) = -0.67, 95% confidence interval (CI) [-1.11, -0.23], P = 0.003, I ² = 20%). Although the alternative ACDFWP was slightly superior in terms of the index of cervical alignment, the limited research on this subject present insufficient evidence. Further well-designed studies are warranted in the future.

Outcomes After Cervical Disc Arthroplasty Versus Stand-Alone Anterior Cervical Discectomy and Fusion: A Meta-Analysis

STUDY DESIGN

Systemic review and meta-analysis.

OBJECTIVES

To review and compare surgical outcomes for patients undergoing stand-alone anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA) for the treatment of cervical spine disease.

METHODS

A systematic search was performed on PubMed, Medline, and the Cochrane Library. Comparative trials measuring outcomes of patients undergoing CDA and stand-alone ACDF for degenerative spine disease in the last 10 years were selected for inclusion. After data extraction and quality assessment, statistical analysis was performed with R software metafor package. The random-effects model was used if there was heterogeneity between studies; otherwise, the fixed-effects model was used.

RESULTS

In total, 12 studies including 859 patients were selected for inclusion in the meta-analysis. Patients undergoing stand-alone ACDF had a statistically significant increase in postoperative segmental angles (mean difference 0.85° [95% confidence interval = 0.35° to 1.35°], P = .0008). Patients undergoing CDA had a decreased rate of developing adjacent segmental degeneration (risk ratio = 0.56 [95% confidence interval = -0.06 to 1.18], P = .0745). Neck Disability Index, Japanese Orthopedic Association score, Visual Analogue Scale of the arm and neck, as well as postoperative cervical angles were similar between the 2 treatments.

CONCLUSIONS

When compared with CDA, stand-alone ACDF offers similar clinical outcomes for patients and leads to increased postoperative segmental angles. We encourage further blinded randomized trials to compare rates of adjacent segmental degeneration and other postoperative outcomes between these 2 treatments options.

Comparing Nonrandomized Observational Studies With Randomized Controlled Trials in Cervical Disc Arthroplasty: A Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To compare the treatment effects of observational studies versus randomized controlled trials (RCTs) in cervical disc arthroplasty.

SUMMARY OF BACKGROUND DATA

RCTs can be logistically challenging and sometimes insufficiently generalizable; well-designed observational studies have been suggested as an alternative. We hypothesized that treatment effects of observational studies in cervical disc arthroplasty are similar to those of RCTs.

METHODS

We searched electronic database from 2000 to 2014. The Neck Disability Index (NDI) was the primary outcome from which the standardized pre-and-post mean difference (Hedges's g) was determined. Meta-analysis was performed to compare Hedges's g from observational studies to that of RCTs. Potential moderator variables including study quality, age, gender, industry sponsorship, location by continent, and disc types were also collected and analyzed. Observational studies were further stratified into prospective and retrospective, and they were compared to each other as well as to RCTs.

RESULTS

We identified nine RCTs, 28 observational studies, and one hybrid study for meta-analysis. NDI Hedges's g was 2.15 for RCTs and 2.03 for observational studies, which was not significant (P = 0.416). No significant difference was found in secondary outcomes. However, after further stratification, prospective observational studies had less treatment effect in Visual Analog Scale neck compared with that of RCTs (1.60 vs. 2.11, P = 0.006). RCTs recruited younger patients (44.1 vs. 45.6, P = 0.008) with worse NDI at baseline (54.30 vs. 46.92, P < 0.001). Patients treated with ProDisc-C showed less standardized improvement on the NDI compared with the patients treated with Prestige (1.41 vs. 2.48, P = 0.026).

CONCLUSION

Prospective observational studies that utilize the same features of RCTs such as inclusion and exclusion criteria validated clinical outcomes, and statistical methods can provide valuable information about the treatment effects on a generalizable population.

LEVEL OF EVIDENCE

4.