Radiological follow-up after implanting cervical disc prosthesis in anterior discectomy: a systematic review

Objective

The objective of this study was to review current literature on the comparison of the radiological outcome of cervical arthroplasty with fusion after anterior discectomy for radiculopathy.

Materials and Methods

A literature search was performed in PubMed, Embase, Web of Science, Cochrane, CENTRAL, and CINAHL using a sensitive search string combination. Studies were selected by predefined selection criteria (patients exclusively suffering from cervical radiculopathy), and risk of bias was assessed using a validated Cochrane checklist adjusted for this purpose. Additionally, an overview of results of articles published in 21 meta-analyses was added, considering a group of patients with myelopathy with or without radiculopathy.

Results

Seven articles that compared intervertebral devices in patients with radiculopathy (excluding patients with myelopathy) were included in the study. Another 31 articles were studied as a mixed group, including patients with myelopathy and radiculopathy. Apart from three studies with low risk of bias, all other articles showed intermediate or high risk of bias. Heterotopic ossification was reported to be present in circa 10% of patients, seemingly predominant in patients with radiculopathy, with a very low level of evidence. Radiological signs of adjacent segment disease were present at baseline in 50% of patients, and there is a low level of evidence that this increased more (10%–20%) in the fusion group at long-term follow-up. However, this was only studied in the mixed study population, which is degenerative by diagnosis.

Conclusion

Although the cervical disc prosthesis was introduced to decrease adjacent level disease, convincing radiological evidence for this benefit is lacking. Heterotopic ossification as a complicating factor in the preservation of motion of the device is insufficiently studied. Regarding purely radiological outcomes, currently, no firm conclusion can be drawn for implanting cervical prosthesis versus performing fusion.