Food and Drug Administration–approved investigational device exemption (IDE) studies have provided level I evidence supporting cervical disc arthroplasty (CDA) as a safe and effective alternative to anterior cervical discectomy and fusion (ACDF). Long-term CDA outcomes continue to be evaluated. Here, the authors present outcomes at 10 years postoperatively for the single-level CDA arm of an IDE study (postapproval study).
The primary endpoint was overall success, a composite variable composed of five criteria: 1) Neck Disability Index score improvement ≥ 15 points; 2) maintenance or improvement in neurological status; 3) no decline in anterior or posterior functional spinal unit (FSU) height of more than 2 mm compared to 6 weeks postoperatively; 4) no serious adverse event (AE) caused by the implant or the implant and the surgical procedure; and 5) no additional surgery classified as a failure. Additional safety and effectiveness measures included numeric rating scales for neck pain and arm pain, SF-36 quality-of-life physical and mental components, patient satisfaction, range of motion, and AEs.
From the reported assessments at 7 years postoperatively to the 10-year postoperative follow-up, the scores for all patient-reported outcomes, rate of overall success (without FSU), and proportion of patients at least maintaining their neurological function remained stable for the CDA group. Nine patients had secondary surgery at the index level, increasing the secondary surgery cumulative rate from 6.6% to 10.3%. In that same time frame, four patients experienced a serious implant or implant/surgical procedure–related AE, for a 10-year cumulative rate of 7.8%. Seven patients had any second surgery at adjacent levels, for a 10-year cumulative rate of 13.8%. Average angular motion at both the index and adjacent levels was well maintained without creating hypermobility. Class IV heterotopic ossification increased from 1.2% at 2 years to 4.6% at 7 years and 9.0% at 10 years. Patient satisfaction was > 90% at 10 years.
CDA remained safe and effective out to 10 years postoperatively, with results comparable to 7-year outcomes and with high patient satisfaction.
Clinical trial registration no.: NCT00667459 (clinicaltrials.gov)