Results from three studies presented at the 2017 French Spine Society Congress (SFCR; June 1–3, Lille, France) have demonstrated the short and long-term safety, efficacy and patient satisfaction with the Zimmer Biomet’s Mobi-C cervical disc.
Thierry Dufour (Paris, France) presented, “Prevalence, progression, and clinical implications of heterotopic ossification after cervical disc arthroplasty at seven years.”
The prospective, randomised, US Food and Drug Administration (FDA) clinical trial followed 389 patients treated with cervical total disc replacement using Mobi-C to determine the prevalence and progression of heterotopic ossification. The study was conducted across 24 sites in the USA, and patients were followed annually to five years and at seven years post-operatively. Heterotopic ossification grades three and four were classified as clinically relevant due to restricted range of motion. The study concluded that the majority of patients (69.2%) presented without clinically relevant heterotopic ossification. In addition, heterotopic ossification was stable, with 89.4% of all patients having no further development from five to seven years. Possible predictors for clinically relevant heterotopic ossification include preoperative obesity and male gender. Patients with clinically relevant heterotopic ossification had a reduced range of motion, but they maintained similar patient-reported Neck Disability Index (NDI) and Visual Analog Scale (VAS) neck pain scores to non-clinically relevant heterotopic ossification patients. At seven years, there were no cases of subsequent surgery because of heterotopic ossification, and patients with clinically relevant heterotopic ossification were equally satisfied with their procedure.
Jean-Paul Steib (Strasbourg, France) presented, “Clinical results of cervical total disc replacement with a self-adjusting mobile core prosthesis after 10-year follow-up,” discussing data from an ongoing, observational, prospective and multi-centre study in which 384 patients received cervical total disc replacement with Mobi-C.
At the time of database close, the assessments at 10-year follow-up were available for 84 patients. The average clinical outcome was favourable at 10 years for the 84 patients. Disability assessed on NDI and pain assessed on VAS for arm and neck pain decreased significantly from pre-operatively baseline to each follow-up. The mean improvement at 10-year follow-up was 22.6% on NDI (95% CI 18.0 to 27.2, p<0.001), 36.6mm on VAS arm pain (95% CI 28.4 to 44.9, p<0.001) and 25.3mm on VAS neck pain (95% CI 18.2 to 32.4, p<0.001). Overall patient satisfaction at 10 years was 94.8%. Researchers concluded that total disc replacement (TDR) maintained favourable clinical outcomes and a very low adjacent disc disease surgery rate following TDR. Overall, TDR with a self-adjusting mobile core prosthesis, like that of Mobi-C, was both effective and safe.
The third presentation on the Mobi-C device was delivered by Jacques Beaurain, who gave the talk, “Re-emergence of symptoms after successful treatment with cervical disc arthroplasty or anterior cervical discectomy and fusion between two to five years follow-up.”
The study was conducted as a subgroup analysis of a prospective, randomised clinical trial conducted at 24 sites in the USA. Researchers evaluated 575 patients randomised (2:1) to receive motion-preserving cervical total disc arthroplasty (TDA) with Mobi-C or anterior cervical discectomy and fusion (ACDF) to determine if patients with early success at two years, also had clinical success at long-term, five-year follow-up.
For the one-level arm at two years, 73.7% of Mobi-C patients and 65.3% of ACDF patients obtained overall success. Among these patients, 84.7% of Mobi-C and 81.1% of ACDF patients continued to demonstrate overall success at five years (p value was not significant). Both groups experienced worsening of NDI scores from two years to five years, but the mean change in NDI score was similar between groups (TDA: +3.1 vs. ACDF: +3.3, p=0.92). For the two-level arm at two years, 69.7% of Mobi-C patients and 37.4% of ACDF patients met the overall success criteria. Of those patients, 83.6% of Mobi-C patients and 64.5% of ACDF patients maintained success at 5 years (p=0.02).
Data showed ACDF compared to Mobi-C patients experienced a re-emergence of symptoms at the five-year follow-up, for one level at 19.1% compared to 15.3% and for two-level at 35.2% compared to 16.4%, respectively. These results suggest that treatment with Mobi-C was more effective than ACDF and provided better maintenance of short-term clinical outcomes and success from 2 to 5 years.