Rush University Seminar Recap
Understanding Failure in Cervical Disc Arthroplasty: From Clinical Outcomes to System-Level Change
By Kelly Campbell, MS
At a recent Rush University Research Seminar in Chicago hosted by Dino Samartzis, ScD, PhD, MSc, three speakers examined cervical disc arthroplasty (CDA) through a shared, but typically unexplored lens: failure. Rather than considering failure an endpoint, the session framed it as a source of insight that spans clinical decision-making, implant performance, and the broader mechanisms by which evidence is translated into practice.
When CDA Works (And When It Doesn’t)
Scott Blumenthal, MD, provided a clinical outcomes perspective drawing on decades of experience, including performing some of the earliest arthroplasty procedures in the United States. A strong proponent of CDA, Blumenthal emphasized that the procedure remains one of the most studied in spine surgery, has a well-established safety profile, and has a revision rate of less than 1.5% at the Texas Back Institute, where he practices. He noted that these revision rates compare favorably with those reported for more established joint arthroplasties, such as hip and knee.
Scott Blumenthal, MD
When failures occur, the reasons are multifactorial. Common causes include implant migration, subsidence, adjacent segment degeneration, osteolysis, and metal allergies. These outcomes are most often linked to three variables: patient selection, surgical technique, and biomechanics.
Notably, failure does not always necessitate a fusion. In approximately 1/3 of revision cases, a true disc-to-disc revision remains feasible, which demonstrates the importance of individualized treatment algorithms and careful reassessment rather than reflexive procedural conversion.
Decoding Failure through Retrieval Analysis
Robin Pourzal, PhD, shifted the discussion to material and biological mechanisms. Retrieval analysis of devices offers a clinical, yet currently limited, window into how and why implants fail.
Findings presented during the session highlighted several pathways of failure, including wear-related particle debris contributing to osteolysis, unexpected material degradation patterns, and rare but notable structural failures such as ceramic fractures. In some cases, bone ingrowth at endplates suggests unexpected interactions between implant structures and patient biology.
Robin Pourzal, PhD
Pourzal emphasized a key limitation in the analysis: the field lacks a sufficiently robust repository of retrieved implants to enable large-scale, generalizable analysis. Current data are often limited to case-level observations, constraining the ability to draw broader conclusions about device performance and failure modes.
From Device Failure to Field Change
Eric Muehlbauer, MJ, CAE, contextualized these findings within the broader role of professional societies in translating evidence to practice. Organizations such as NASS serve as intermediaries between emerging data and real-world implementation, shaping not only clinical guidance, but also education, coding, and reimbursement structures.
In this model, failure is part of the feedback loop. Clinical outcomes inform research, research informs guidelines, and guidelines ultimately influence both practice patterns and payment systems. As Muehlbauer noted, the translation of evidence into reimbursement pathways represents a critical, and often underappreciated, lever in driving adoption of safer, more effective care.
Eric Muehlbauer, MJ, CAE
Taken together, the session highlighted how a shift in failure in CDA can be understood. Advancing this work will require continued clinical and scientific inquiry, as well as more intentional mechanisms for data collection and sharing. This is particularly true in areas such as retrieval analysis, where the current evidence base remains fragmented and more coordinated approaches to advancing the field.