Document Type

Conference Proceeding

Publication Date

12-2024

Publication Title

Abstract Book 52nd Annual Meeting

Abstract

Introduction: Anterior Cervical Discectomy and Fusion (ACDF) is highly successful at a single level with greater than 90% fusion rates and high patient satisfaction. However, multi-level ACDF surgery, though still successful, has diminishing results with increasing levels. With many Investigational Device Exemption (IDE) clinical trials for the treatment of Symptomatic Cervical Disc Disease (SCDD) at a single level and recent IDE clinical trials for two contiguous levels, these trials offer the opportunity to compare clinical outcomes utilizing the same motion sparing technology mechanisms of action (MOA). The hypothesis is that cervical total disc replacement (cTDR) maintains its clinical benefits from single to multi-level procedures. Materials and Methods: As part of prospective, randomized, multi-center, controlled IDE clinical trials, 103 patients received cTDR at a single level (Murrey et al.) and 133 patients received two-level cTDR. In both trials, the MOA was a semi-constrained ball-in-socket design. Under IRB approval, patients met similar inclusion/exclusion criteria and were consented. All patients were seen for follow-up at 6 weeks, 3 months, 6 months, 12 months, and 24 months. Patient-reported outcome measures and radiographs were collected at each in-office follow up. The primary endpoint was composite clinical success (CCS) at 24 months where a patient must be a success in all 4 criteria, defined as: ≥ 15 point improvement in Neck Disability Index (NDI) Score (out of 100) in subjects at 24 months compared with baseline, maintenance or improvement in neurological status at 24 months compared to baseline, no secondary surgical interventions at the index levels, and absence of major device-related adverse events. Secondary endpoints such as Visual Analog Score (VAS) neck pain, VAS arm pain, and VAS satisfaction were collected at each in-office time point. Results: At 24 months, CCS was achieved in 72.3% of the single-level patients and 88.2% of the two-level patients. There was 1 major device-related adverse event in the single-level and none in the two-level study. There was no difference in the incidence of secondary surgical interventions between groups. Similar NDI scores over time were seen between groups showing statistically significant improvement from pre-operative (single-level: 53.9±15.0: two-level: 58.8±15.8) to 24 month (single level: 21.4±20.2; two level: 14.2±16.7). At 24 month, the mean difference between groups was statistically significant (p ≤ 0.05). In addition, there was a statistically significant difference in patients achieving NDI success which was achieved in 79.8% of single level and 95.3% of two level patients. All secondary endpoints consistently showed similar improvement from baseline for both groups but none of the measures showed a statistically significant difference between treatments. Conclusion: The comparison of these two IDE clinical trials for the treatment of Symptomatic Cervical Disc Disease (SCDD) at a single or two levels is counterintuitive and profound. Unlike what is classically seen in ACDF surgery, the two level cTDR patients had greater clinical success. This could be a consequence of almost two decades of greater experience in the spine community. However, with greater understanding of the degenerative cascade, possibly what we once considered a single level patient was truly a two level patient.

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307

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52nd Annual Meeting of the Cervical Spine Research Society, December 11-14, 2024, Chicago, IL

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307

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