Four-year results of a prospective single-arm study on 200 semi-constrained total cervical disc prostheses: clinical and radiographic outcome

Hans Jörg Meisel, Lubomír Jurák, Jussi Antinheimo, Ricardo Arregui, Bernhard Bruchmann, Mario Čabraja, Fabrizio Caroli, Stefan Kroppenstedt, Jan Kryl, Juha Pohjola, Ian Shackleford, Steffen Sola, Peter Stosberg, Jan Stulik, Christian Woiciechowsky, Petr Suchomel

Research output: Contribution to journalArticlepeer-review


OBJECTIVE Recent studies have described encouraging outcomes after cervical total disc replacement (cTDR), but there are also critical debates regarding the long-term effects of heterotopic ossification (HO) and the prevalence of adjacent-level degeneration. The aim in this paper was to provide 4-year clinical and radiographic outcome results on the activ C disc prosthesis. METHODS A total of 200 subjects underwent single-level activ C (Aesculap AG) implantation between C-3 and C-7 for the treatment of symptomatic degenerative disc disease. Clinical and radiographic assessments were performed preoperatively, intraoperatively, at discharge, and again at 6 weeks, 6 months, 1 year, 2 years, and 4 years. Radiographic evaluations were done by an independent core laboratory using a specific software for quantitative motion analysis. RESULTS Neck Disability Index (NDI) and visual analog scale (VAS) score for neck and arm pain decreased significantly from baseline to the 4-year follow-up. The mean improvement for NDI was 20, for VAS severity and frequency of neck pain 26.4 and 28, and for VAS severity and frequency of arm pain 30.7 and 35.1, respectively. The neurological situation improved for the majority of patients (86.4%); 76.1% of cases were asymptomatic. Subsequent surgical interventions were reported in 7% of the cases, including device removals in 3%. In 2.5% a subsidence greater than 3 mm was recorded; 1 of these cases also had a migration greater than 3 mm. No device displacement, expulsion, disassembly, loose or fractured device, osteolysis, or facet joint degeneration at the index level was observed. Segmental lordotic alignment changed from -2.4° preoperatively to -6.2° at 4 years, and postoperative height was maintained during the follow-up. Advanced HO (Grade III and IV) was present in 27.1% of the cases; 82.4% showed segmental mobility. A progression of radiographic adjacent-segment degeneration occurred in 28.2%, but only 4.5% required surgical treatment. CONCLUSIONS The activ C is a safe and effective device for cervical disc replacement confirming the encouraging results after cTDR. Clinical trial registration no.: NCT02492724 ( ).

Original languageEnglish
Pages (from-to)556-565
Number of pages10
JournalJournal of Neurosurgery: Spine
Issue number5
Publication statusPublished - Nov 1 2016


  • ACDF = anterior cervical discectomy and fusion
  • activ C
  • adjacent-segment degeneration
  • AE = adverse event
  • AP = anteroposterior
  • ASD = adjacent-segment disease
  • BMI = body mass index
  • cervical spine
  • clinical outcome
  • COI = conflict of interest
  • COR = center of rotation
  • cTDR = cervical total disc replacement
  • degenerative disc disease
  • FJD = facet joint degeneration
  • heterotopic ossification
  • HO = heterotopic ossification
  • long-term results
  • NDI = Neck Disability Index
  • Neck Disability Index
  • range of motion
  • RCT = randomized controlled trial
  • ROM = range of motion
  • total disc replacement
  • VAS = visual analog scale
  • visual analog scale

ASJC Scopus subject areas

  • Medicine(all)


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