Randomized controlled trials comparing cervical disc arthroplasty and anterior cervical discectomy and fusion outcomes in degenerative spine disease: a systematic review and meta-analysis

J Neurosurg Spine 43:703–716, 2025

This systematic review and meta-analysis synthesizes randomized controlled trials comparing cervical disc arthroplasty (CDA) with anterior cervical discectomy and fusion (ACDF) for degenerative cervical disc disease. Across 25 RCTs (4530 patients), CDA demonstrated higher overall and neurological success, reduced adjacent-segment disease and fewer reoperations, but increased heterotopic ossification and longer operative times.

The authors performed multilevel meta-analysis and meta-regression to explore heterogeneity, finding myelopathy inclusion and follow-up completeness influenced results; sensitivity analyses excluding industry-funded trials showed consistent findings. Conclusions emphasize CDA’s potential benefits for selected patients while recommending longer-term and subgroup-specific trials.

Cervical Disc Arthroplasty (CDA) vs. Anterior Cervical Discectomy and Fusion (ACDF): CDA shows comparable or potentially greater overall and neurological success rates compared to ACDF for degenerative cervical spine disease.

Motion Preservation: CDA preserves cervical spine range of motion at the operated level, while ACDF is associated with loss of motion and potentially increased risk of adjacent segment degeneration (ASD).

Adjacent Segment Disease (ASD): CDA is associated with a significantly lower rate of ASD compared to ACDF, suggesting a protective effect against degeneration of adjacent spinal segments.

Reoperation Rates: CDA results in lower total reoperation rates compared to ACDF, indicating fewer subsequent surgical interventions.

Heterotopic Ossification (HO): CDA has a significantly higher rate of HO, a complication where bone forms in soft tissue, which can potentially reduce the motion-preserving benefit of the procedure.

Operative Time: CDA procedures are associated with significantly longer operative times than ACDF, with no significant difference in blood loss or hospital length of stay between the two techniques.

Pain and Disability Outcomes: No significant differences were found between CDA and ACDF in terms of improvement in arm pain, neck pain, or disability scores (Neck Disability Index) as measured by patient-reported outcomes.

Patient Selection: The benefits of CDA over ACDF are most applicable to patients with 1-2 level degenerative disease, preserved cervical alignment, and no significant instability or deformity; findings may not generalize to more complex cases.

Dynamic posterior stabilization for degenerative lumbar spine disease

DSS

Eur Spine J (2016) 25:2563–2570

Dynamic stabilization of the degenerated spine was invented to overcome the negative side effects of fusion surgery like adjacent segment degeneration. Amongst various different implants DSS  is a pedicle-based dynamic device for stabilizing the spine and preserving motion. Nearly no clinical data of the implant have been reported so far. The current analysis presents results from a single spine surgeon who has been using DSS  for the past 5 years and recorded all treatment and outcome data in the international Spine Tango registry.

Materials/methods: From the prospectively documented overall patient pool 436 cases treated with DSS  could be identified. The analysis was enhanced with a mailing of COMI patient questionnaires for generating longer-term follow-ups up to 4 years.

Results: 387 patients (189 male, 198 female; mean age 67.3 years) with degenerative lumbar spinal disease including degenerative spondylolisthesis (6.1 %) could be evaluated. The type of degeneration was mainly spinal stenosis (89.9 %). After a mean follow-up of 1.94 years, the COMI score and NRS back and leg pain improved significantly and to a clinically relevant extent. The postoperative trend analysis could not determine a relevant deterioration of these outcomes until 4 years postoperative. 10 patients were revised (2.6 %) and the implant was removed; in most cases, a fusion was performed. Another 5 cases (1.3 %) had an extension of the dynamic stabilization system to the adjacent level. 84.2 % of patients rated that the surgery had helped a lot or had helped.

Discussion: The results of this large consecutive series with a follow-up up to 4 years could demonstrate a good and stable clinical outcome after posterior dynamic stabilization with DSS. For degenerative diseases of the lumbar spine, this treatment seems to be a valid alternative to fusion surgery.

Impact of Body Mass Index on Adjacent Segment Disease After Lumbar Fusion for Degenerative Spine Disease

Impact of Body Mass Index on Adjacent Segment Disease After Lumbar Fusion for Degenerative Spine Disease

Neurosurgery 76:396–402, 2015

Adjacent segment disease is an important complication after fusion of degenerative lumbar spines. However, the role of body mass index (BMI) in adjacent segment disease has been addressed less.

OBJECTIVE: To examine the relationship between BMI and adjacent segment disease after lumbar fusion for degenerative spine diseases.

METHODS: For this retrospective study, we enrolled 190 patients undergoing lumbar fusion surgery for degeneration. BMI at admission was documented. Adjacent segment disease was defined by integration of the clinical presentations and radiographic criteria based on the morphology of the dural sac on magnetic resonance images.

RESULTS: Adjacent segment disease was identified in 13 of the 190 patients, accounting for 6.8%. The interval between surgery and diagnosis as adjacent segment disease ranged from 21 to 66 months. Five of the 13 patients required subsequent surgical intervention for clinically relevant adjacent segment disease. In the logistic regression model, BMI was a risk factor for adjacent segment disease after lumbar fusion for degenerative spine diseases (odds ratio, 1.68; 95% confidence interval, 1.27- 2.21; P < .001). Any increase of 1 mean value in BMI would increase the adjacent segment disease rate by 67.6%. The patients were subdivided into 2 groups based on BMI, and up to 11.9% of patients with BMI ≥25 kg/m2 were diagnosed as having adjacent segment disease at the last follow-up.

CONCLUSION: BMI is a risk factor for adjacent segment disease in patients undergoing lumbar fusion for degenerative spine diseases. Because BMI is clinically objective and modifiable, controlling body weight before or after surgery may provide opportunities to reduce the rate of adjacent segment disease and to improve the outcome of fusion surgery.