Comparison of Recruitment Method on Clinical Outcomes Following Cervical Disc Arthroplasty.

Abstract

Study design: Retrospective cohort.

Objective: To compare the clinical outcomes of trial versus standard clinical practice (SCP) patients following cervical disc arthroplasty (CDA).

Background: CDA is hypothesized to reduce the shear strain and related complications resulting from fusion procedures. CDA has gained significant traction in recent decades. The typical non-trial patient undergoing CDA does not undergo the same level of preoperative scrutiny as those treated in formal clinical trials. Concerns exist about diverging clinical outcomes between these groups.

Methods: This investigation retrospectively reviews prospectively collected data on one and two-level CDA patients from C3-T1. Patients were recruited into randomized, controlled trials or SCP practice beginning in 2002 or 2018, respectively. One-year minimum follow-up was required. Hybrid constructs and prior cervical spine surgical history have been excluded. Clinical assessments included reoperation history and the patient-reported outcome measures of Visual Analog Scale (VAS) neck, VAS arm, and Neck Disability Index (NDI). Data was collected at the preoperative, postoperative, one-year, two-year, three-year, five-year, and ten-year time points.

Results: One hundred and sixty-eight patients underwent CDA at 193 cervical levels, including 104 trial patients and 64 SCP patients. Mean follow-up for the entire cohort was 6.1 years (0.9 - 20.4 years). Eight unique disc designs were utilized. Trial patients had a greater proportion of females and longer follow-up duration (P<0.05). Trial patients had significantly worse preoperative clinical scores with greater improvements at each follow-up time point. SCP patients had significantly higher index-level reoperation rates at five years.

Conclusion: Trial patients have lower rates of reoperation and improved clinical performance which could be in part due to more stringent selection criteria. This study is limited by long-term SCP response rates. Additional studies with larger cohorts are needed to improve our understanding of disc implant performance.