Clinical Outcomes of a PEEK-on-Ceramic Cervical Total Disc Replacement Presented at ISASS 2020
Clinical Outcomes of a PEEK-on-Ceramic Total Disc Replacement: Data from Three Sites Participating in the Two-Level Cervical FDA IDE Trial
Presented at the International Society for the Advancement of Spine Surgery (ISASS), February 28, 2020
To date, good results have been reported for a variety of cervical total disc replacements (TDRs). These devices have most commonly been made of metallic endplates with a plastic core. A few metal-on-metal devices have also been described. The use of PEEK for spinal implants continues to increase, primarily due to its mechanical properties and positive imaging properties (i.e. no metallic artifact on MRI or CT). A TDR was designed with titanium-coated PEEK endplates and a biconvex zirconia toughened alumina ceramic core. While there are multiple prospective studies reporting on single-level TDR, there is much less prospective data available for two-level procedures.
The purpose of this study was to evaluate the preliminary results of 3 sites participating in the two-level Investigational Device Exemption (IDE) study for a PEEK-on-ceramic TDR.
The data were from 3 centers participating in the TDR arm of a prospective study evaluating two-level cervical TDR using a non-concurrent historical control.
The device was implanted into 38 patients at 3 of 18 sites participating in the FDA IDE trial for two-level cervical disc degeneration. Twelve-month data were available for 30 patients.
Length of follow-up:
Data presented are through 12-month follow-up.
Patient reported outcome measures included the Neck Disability Index (NDI), visual analog scales (VAS) separately assessing neck and arm pain, and disc height of the operated segments measured from radiographs.
Patients enrolled in the trial received the Simplify® PEEK-on-ceramic TDR. Evaluations were conducted prior to surgery and at 6 weeks, and 3, 6, and 12 months after surgery. Radiographs were also analyzed at discharge after surgery. All radiographs were analyzed by an independent lab specializing in image assessment.
There were decreases (p<0.01) in NDI, and neck and arm pain scores by 6-week follow-up (Figures 1 and 2) which was maintained throughout 12-month follow-up. The mean NDI decreased from 62.6 pre-op, to less than 15 at all follow-up visits of 3 months or longer. The pre-operative neck and arm pain scores were 8.7 and 9.1, respectively and, decreased post-op to values of 2 or less at follow-up visits of 3 months or longer. The mean disc height was increased at discharge (p<0.01) and remained increased from pre-operative disc height throughout follow-up (Figure 3). The mean height of the superior TDR level increased from 3.2 mm pre-op to 4.5 mm at 12 months post-op. The mean height of the inferior level was 3.0 mm prior to surgery and 4.0 mm at 12 months.
Preliminary results of this IDE study found the PEEK-on-ceramic disc replacement produced decreases in pain and function scores compared to the pre-operative values, which were maintained through 12-month follow-up. Disc height of the operated segments were increased after surgery and remained increased through 12-month follow-up. These early results were similar to those reported earlier for other devices, in patients undergoing TDR at 2-levels.