71. Long-term follow-up of a consecutive series with prodisc C Nova at a single institution

BACKGROUND CONTEXT Cervical total disc replacement surgery has more than two decades of experience. Device designs that feature a ball and socket mechanism with central keels, such as the original prodisc C, have been shown to perform favorably. However, a tall central keel can potentially be less than optimal for patients with shorter vertebral bodies or in multi-level cases. A variation of the prodisc C design was subsequently created, keeping the original mechanism of action but changing to shorter, tri-keel fixation. prodisc C Nova (Centinel Spine, West Chester, PA), which has one central keel cranially and two lateral keels caudally, was developed and released in Europe in 2010. PURPOSE The primary objective of this study was to evaluate the long-term clinical and radiographic outcomes. STUDY DESIGN/SETTING Prospective, consecutive series. PATIENT SAMPLE Fifty-six patients (37 Female, 19 Male) underwent total disc replacement surgery for symptomatic cervical disc disease at a single level. OUTCOME MEASURES Evaluation at each visit included patient self-assessments, eg, visual analog scale (VAS) pain and satisfaction, walking, physical and neurological examination, and radiographic evaluation. Radiographic evaluation was performed by an independent radiologic group (Medical Metrics, Houston, Texas). METHODS After failing conservative therapy, patients were evaluated for their suitability for surgical intervention of their symptomatic cervical disc degeneration. Patients underwent an anterior discectomy and total disc replacement. The clinical status of each patient was evaluated pre- and postoperatively at 6 weeks, 3 months, 6 months, 1 year and annually thereafter. RESULTS Patients were followed through 9 years postoperatively. At baseline, the average age was 48.22 ± 8.98 years and an average BMI 27.68 ± 4.78 kg/m2. VAS neck and VAS arm pain both showed statistically significant reduction from baseline by 6 weeks postop and were maintained through 9 years. VAS neck was 6.67 ±2.29 mm at baseline and 3.25 ± 3.59 mm at 9 years. VAS arm was 6.02 ±2.59 mm preoperatively and 4.00 ± 3.65 mm at 9 years. Patients reported high satisfaction and willingness to have operation again at all time points. Patients walking frequency increased by month 3 and was maintained in ≥ 75% of patients at all timepoints out to 9 years. Radiographic results showed no migration or protrusions through 9 years follow-up. One case of minor subsidence was measured after 5 years but did not require surgical intervention and had satisfactory results. One patient required reoperation at 10 months for persistent pain and required facet denervation at both cranial and caudal adjacent levels as well as index level. The disc remained intact and had good follow-up. There were no device failures. CONCLUSIONS Long-term follow-up shows that prodisc C Nova has patient-reported outcomes and radiographic results comparable to that published with prodisc C. Patients reported consistent and sustained improvement through 9 years of follow-up. Not only was pain relief achieved but functional improvement through walking was sustained. There were also no adjacent level surgeries over the 9 years, showing that maintaining motion has other potential clinical benefits beyond the index level. The change in keel fixation design did not affect patient outcomes, providing another option for some patients. FDA DEVICE/DRUG STATUS prodisc C Nova (Investigational/Not approved)