Artificial disc replacement and adjacent-segment pathology: 10-year outcomes of a randomized trial

Michael Kontakis; Catarina Marques; Håkan Löfgren; Firas Mosavi; Martin Skeppholm; Claes Olerud; Anna MacDowall

doi:10.3171/2021.9.SPINE21904

Artificial disc replacement and adjacent-segment pathology: 10-year outcomes of a randomized trial

J Neurosurg Spine. 2021 Dec 17;36(6):945-953. doi: 10.3171/2021.9.SPINE21904. Print 2022 Jun 1.

Authors

Michael Kontakis¹, Catarina Marques¹, Håkan Löfgren², Firas Mosavi³, Martin Skeppholm⁴, Claes Olerud¹, Anna MacDowall¹

Affiliations

¹ 1Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden.
² 2Neuro-Orthopaedic Center, Jönköping, and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
³ 3Department of Radiology, Uppsala University Hospital, Uppsala, Sweden; and.
⁴ 4Department of Learning, Informations, Management and Ethics (LIME), Medical Management Center, Health Economics and Health Evaluation Research Group, Karolinska Institutet, Stockholm and Center for Spine Surgery in Stockholm, Sophiahemmets Sjukhus, Stockholm, Sweden.

PMID: 34920425
DOI: 10.3171/2021.9.SPINE21904

Abstract

Objective: Artificial disc replacement (ADR) is designed to preserve motion and thus protect against adjacent-segment pathology (ASP) and act as an alternative treatment to fusion surgery. The question remains, how well do ADR devices perform after 10 years of follow-up compared with fusion surgery in terms of patient satisfaction, sustainability, and protection against ASP?

Methods: This was the 10-year follow-up study of 153 participants who underwent ADR or fusion surgery after anterior decompression due to cervical degenerative radiculopathy (ISRCTN registration no. 44347115). Scores on the Neck Disability Index (NDI), EQ-5D, and visual analog scale for neck and arm pain were obtained from the Swedish Spine Registry and analyzed using ANCOVA. Information about secondary surgical procedures was collected from medical records and presented as Kaplan-Meier curves. MRI and flexion-extension radiography were performed, and ASP was graded according to the Miyazaki classification system.

Results: Ten participants were lost to follow-up, which left 143 participants (80 underwent ADR and 65 underwent anterior cervical discectomy and fusion). There were no differences between groups in terms of patient-reported outcome measures (10-year difference in NDI scores 1.7 points, 95% CI -5.1 to 8.5, p = 0.61). Nineteen (24%) participants in the ADR group compared with 9 (14%) in the fusion group underwent secondary surgical procedures. The higher reoperation rate of the ADR group was mainly due to 11 female participants with device loosening. The rates of reoperation due to ASP were similar between groups, which was confirmed with MRI assessment of ASP that also showed no differences between the groups (p = 0.21).

Conclusions: This was the first 10-year follow-up study to compare ADR with fusion surgery and to provide MRI information for the assessment of ASP. The authors found no benefit of ADR over fusion surgery after anterior decompression for cervical degenerative radiculopathy.

Keywords: adjacent-segment pathology; anterior decompression and fusion; artificial disc replacement; cervical radiculopathy; degenerative; randomized trial.