326 - Impact of Age on Patient Outcomes after Cervical Disc Arthroplasty or...

General Session: Cervical-1

Presented by: M. Hisey - View Audio/Video Presentation (Members Only)

Author(s):

M. Hisey(1), J. Zigler(2), R. Guyer(2), D. Ohnmeiss(3)

(1) Texas Back Institute, Denton, TX, United States
(2) Texas Back Institute, Plano, TX, United States
(3) Texas Back Institute Research Foundation, Plano, TX, United States

Abstract

Introduction: When treating cervical degenerative disc disease, surgeons have the option of using cervical disc arthroplasty (CDA) or traditional anterior cervical discectomy and fusion (ACDF). There is little information available on the impact of age on outcomes after these procedures. The purpose of this study was to assess the potential impact of patient age on CDA and ACDF outcomes at 5 years after surgery using data from a prospective, randomized, clinical trial.

Methods: The study was based on 575 patients randomized 2:1 to CDA (389 patients, Mobi-C cervical disc prosthesis, LDR Spine) or ACDF (186 patients, allograft and anterior plate) at one or two cervical levels. Outcomes were assessed 5 years postoperative. For univariable analyses, patients were stratified by age with those < 50 years old in one group and patients >50 years old in another. Patient demographics, Neck Disability Index (NDI), visual analog scales (VAS) assessing neck pain, SF-12 PCS scores, NDI success and secondary surgery rates were analyzed. NDI success was defined as >50% improvement for patients with a preoperative NDI score of < 60, or >30 points of improvement for patients with an NDI score of 60 or greater. For multivariate analyses, logistic regression was used.

Results: The mean preoperative age was 44.6 years (range 21 to 67). In univariate analyses, no significant differences in outcomes were was observed with respect to age in patients receiving either CDA or ACDF. At 5 years, CDA patients < 50 years old and those >50 years old had similar NDI improvement (36.6 vs. 36.9, p>0.90), VAS neck pain improvement (44.4 vs. 41.7, p>0.40) and SF-12 PCS improvement (9.0 vs. 9.7, p>0.60). The rates of NDI success (78.1% vs. 84.2%, p>0.30) and secondary surgery (4.5% vs. 5.0%, p>0.90) were also similar between the age groups in CDA patients. For ACDF patients, age groups also had similar outcomes for NDI improvement (31.1 vs. 29.7, p>0.60), VAS neck pain improvement (42.0 vs. 39.3, p>0.60), and SF-12 PCS improvement (8.0 vs. 10.1, p>0.40). ACDF patients had similar rates of NDI success in the two age groups (68.5% vs. 62.2%, p>0.50). However, in the ACDF group, patients < 50 years old trended toward a higher secondary surgery rate than those >50 years (20.4% vs. 6.4%, p>0.050). When comparing secondary surgery rates between treatment groups, patients >50 years of age had similar subsequent surgery rates (p>0.75). However, in patients < 50 years of age, the ACDF group had a significantly higher rate of subsequent surgery than their CDA counterparts (p< 0.0001). In multivariable logistic regression, age was not a significant predictor of NDI success (OR: 1.01, CI: 0.99 - 1.04) when adjusting for gender, levels treated, and treatment group. Similarly, for secondary surgery, age was also not a significant predictor (OR: 0.97, CI: 0.93 - 1.01) when adjusting for gender, treatment group, levels treated, and preoperative NDI.

Conclusion: In this clinical trial population, there was no difference in outcomes based on age in either the TDR or ACDF groups. However, a higher rate of subsequent surgery in ACDF patients less than 50 years old suggests that CDA may provide a benefit over ACDF for these patients.