The Discover artificial disc replacement versus fusion in cervical radiculopathy--a randomized controlled outcome trial with 2-year follow-up.
BACKGROUND
Several previous studies comparing artificial disc replacement (ADR) and fusion have been conducted with cautiously positive results in favor of ADR. This study is not, in contrast to most previous studies, an investigational device exemption study required by the Food and Drug Administration for approval to market the product in the United States. This study was partially funded with unrestricted institutional research grants by the company marketing the artificial disc used in this study.


OBJECTIVE
To compare outcomes between the concepts of an artificial disc to treatment with anterior cervical decompression and fusion (ACDF) and to register complications associated to the two treatments during a follow-up time of 2 years.


METHODS
This is a randomized controlled multicenter trial, including three spine centers in Sweden.


METHODS
The study included patients seeking care for cervical radiculopathy who fulfilled inclusion criteria. In total, 153 patients were included.


METHODS
Self-assessment with Neck Disability Index (NDI) as a primary outcome variable and EQ-5D and visual analog scale as secondary outcome variables.


METHODS
Patients were randomly allocated to either treatment with the Depuy Discover artificial disc or fusion with iliac crest bone graft and plating. Randomization was blinded to both patient and caregivers until time for implantation. Adverse events, complications, and revision surgery were registered as well as loss of follow-up.


RESULTS
Data were available in 137 (91%) of the included and initially treated patients. Both groups improved significantly after surgery. NDI changed from 63.1 to 39.8 in an intention-to-treat analysis. No statistically significant difference between the ADR and the ACDF groups could be demonstrated with NDI values of 39.1 and 40.1, respectively. Nor in secondary outcome measures (EQ-5D and visual analog scale) could any statistically significant differences be demonstrated between the groups. Nine patients in the ADR group and three in the fusion group underwent secondary surgery because of various reasons. Two patients in each group underwent secondary surgery because of adjacent segment pathology. Complication rates were not statistically significant between groups.


CONCLUSIONS
Artificial disc replacement did not result in better outcome compared to fusion measured with NDI 2 years after surgery.
Stockholm Spine Center, Löwenströmska Hospital, SE-194 89, Upplands Väsby, Sweden; Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska Universitetssjukhuset Solna (L1:00), 171 76 Stockholm, Sweden. Electronic address: martin.skeppholm@spinecenter.se.
Martin
M
Skeppholm
Stockholm Spine Center, Löwenströmska Hospital, SE-194 89, Upplands Väsby, Sweden.
Lars
L
Lindgren
Stockholm Spine Center, Löwenströmska Hospital, SE-194 89, Upplands Väsby, Sweden.
Thomas
T
Henriques
Neuro-Orthopaedic Center, Ryhov Hospital, 553 05 Jönköping, Sweden.
Ludek
L
Vavruch
Neuro-Orthopaedic Center, Ryhov Hospital, 553 05 Jönköping, Sweden.
Håkan
H
Löfgren
Department of Orthopaedics, Uppsala University Hospital, Akademiska sjukhuset, 751 85 Uppsala, Sweden.
Claes
C
Olerud
D000328:Adult; D002574:Cervical Vertebrae / Q000601:surgery*; D004185:Disability Evaluation; D017586:Diskectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011843:Radiculopathy / Q000601:surgery*; D012086:Reoperation; D013123:Spinal Fusion; D059145:Total Disc Replacement / Q000379:methods*; D016896:Treatment Outcome; D014481:United States
Artificial disc replacement; Cervical radiculopathy; Cervikal fusion; Clinical outcome; EQ-5D; Neck Disability Index; Randomized controlled trial