390 - Radiographic Adjacent Segment Pathology Following Treatment with TDR o...

General Session: Cervical Degenerative

Presented by: P. Nunley - View Audio/Video Presentation (Members Only)


P. Nunley(1), D. Cavanaugh(1), E. Kerr(1), A. Utter(1), K. Frank(1), M. Stone(1)

(1) Rothman Institute, Thomas Jefferson University, Department of Orthopedic Surgery, Egg Harbor, NJ, United States
(2) Laser Spine Institute, Tampa, FL, United States
(3) Texas Back Institute, Plano, TX, United States
(4) Spine Institute of Louisiana, Shreveport, LA, United States
(5) Ortho Northeast, Fort Wayne, IN, United States
(6) Orange County Neurosurgical Associates, Laguna Hills, CA, United States
(7) Cedars Sinai Medical Center, Los Angeles, CA, United States
(8) Hospital for Special Surgery, New York, NY, United States
(9) Carolina Neurosurgery & Spine Associates, Charlotte, NC, United States
(10) University of California, Davis, Davis, CA, United States


Introduction: Adjacent segment pathology (ASP) continues to be a major concern for patients undergoing treatment with CDA or ACDF. Degenerative changes at adjacent levels after initial surgical treatment can lead to the reemergence of symptoms prompting additional surgical intervention. The motion preserving capabilities of CDA have been documented and are hypothesized to produce lower rates of ASP compared to ACDF. However, few studies have explored the influence of CDA on ASP in the long-term. More importantly, evidence of the effect of multilevel CDA on ASP is limited. Here we evaluate and compare radiographic ASP (rASP) in patients treated with one- or two-level ACDF or CDA.

Methods: Data was collected in a prospective, randomized, controlled clinical trial comparing total disc replacement (Mobi-C© artificial disc) to ACDF with allograft and anterior plate at one or two contiguous levels. The patient population consisted of 575 randomized patients: 164 patients were treated with one-level CDA and 81 with one-level ACDF; 225 patients were treated with two-level CDA and 105 with two-level ACDF. Inclusion criteria included a diagnosis of symptomatic cervical degenerative disc disease at one or two levels and no history of cervical spine surgery. The Kellgren-Lawrence scale of disc degeneration was used to define rASP. Progressing rASP was defined as any change in grade from preoperative. Independent radiologists conducted all radiographic evaluations (Medical Metrics, Inc., Houston, TX).

Results: At 7 years, total radiographic follow-up was 74.6%. Patients within treatment arms were evenly matched at baseline. For the one-level treatment arm, significant rASP (Grades III-IV) was less prevalent in CDA patients than in the ACDF patients at superior (13.3% vs. 27.9%, p=0.05) and inferior (22.2% vs. 40.7%, p=0.08) adjacent levels at 7 years. The rate of significant rASP (Grades III-IV) was also lower in the two-level CDA group compared to the two-level ACDF group at superior (11.0% vs. 26.7%, p=0.006) and inferior (5.3% vs. 40.0%, p< 0.0001) adjacent levels. CDA patients in the one-level cohort experienced significantly less degenerative changes from baseline at the superior or inferior adjacent level at 7 years than ACDF patients (58.9% vs. 76.7%, p=0.04). Similarly, two-level CDA patients demonstrated less degenerative changes than ACDF (50.0% vs. 87.5%, p< 0.0001).

Conclusion: Seven-year data validates the hypothesis that CDA patients undergo less rASP than ACDF patients do for both one and two levels. Interestingly, differences in rASP were more pronounced in patients treated with a two level vs. one level procedure. However, clinical correlations are still needed to further understand the relationship between rASP and clinical outcomes following both CDA and ACDF.