Simplify Disc Cervical Disc Replacement Prospective Data from FDA IDE Trial for Single-level Surgery Presented at NASS 2020

Abstracts

161. Cervical Disc Replacement Using a PEEK-on-Ceramic Implant: Prospective Data from Seven Sites Participating in an FDA IDE Trial for Single-level Surgery

Richard D. Guyer, MD1; Domagoj Coric, MD2; Cameron N. Carmody, MD3; Rick C. Sasso, MD4; Michael J. Musacchio, MD5; Hyun W. Bae, MD6; Donna D. Ohnmeiss, PhD7

1Center for Disc Replacement at Texas Back Institute, Plano, TX, US; 2Carolina Neurosurgery & Spine Associates, Charlotte, NC, US; 3Texas Spine Consultants, Addison, TX, US; 4Indiana Spine Group, Carmel, IN, US; 5NorthShore University HealthSystem, Evanston, IL, US; 6Spine Institute St. John’s Health Center, Los Angeles, CA, US; 7Texas Back Institute Research Foundation, Plano, TX, US

Presented at the North American Spine Society (NASS), October 9, 2020

Background

The first cervical total disc replacements (TDRs) used on a large-scale basis, produced motion through a ball-and-socket action, with metal endplates articulating with a plastic core. Various designs followed- metal-on-metal devices, a titanium-ceramic composite device, as well as a compressible disc with metal endplates. The use of PEEK material for spinal implants continues to increase, primarily due to its mechanical 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.

Purpose

The purpose of this study was to evaluate preliminary results of 7 sites participating in the single-level Investigational Device Exemption (IDE) study for a PEEK-on-ceramic TDR.

Design/Setting

This is a prospective study evaluating the cervical TDR using a non-concurrent historical control. Data from 7 of 16 sites participating in the investigational arm are provided.

Patients

The device was implanted into 123 patients at 7 of 16 sites participating in the FDA IDE trial for single-level cervical degenerative radiculopathy with or without spinal cord compression from C3 to C7. Twelve-month data were available for 120 patients and 24-month data were available for 87 patients.

Outcome measures

Outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS) assessing neck and arm pain, and the Dysphagia Handicap Index (DHI). Radiographic assessment of the operated level included disc height, flexion/extension range of motion, and lordosis.

Methods

Patients enrolled in the trial received the Simplify PEEK-on-ceramic TDR. Evaluations were conducted prior to surgery and within 2 weeks, 6 weeks, and 3, 6, 12, and 24 months after surgery. Radiographs were analyzed by an independent lab specializing in image assessment.

Results

Mean NDI scores decreased significantly (p<0.01) from 61.9 pre-operatively to 15.1 at 12 months and 14.8 at 24 months. Mean VAS pain scores also decreased significantly, from 81.3 (on a scale of 0-100, p<0.01) to 16.8 and 18.0 at 12 and 24 months, respectively. Pre-operatively, the mean DHI score was 5.4. This increased to 6.9 at 6 week follow-up, and decreased to less than 4.5 at all other follow-up points. On radiographic measures, the mean disc height was 3.3 mm prior to surgery and was significantly increased (p<0.01) throughout follow-up with values of 4.3 and 4.1 mm at 12 and 24 months. The mean flexion/extension range of motion at the TDR level was 7.1o prior to surgery and increased significantly (p<0.05) to 8.9o at 12 months and 9.4o at 24 months. The mean lordosis at the operated level also increased significantly (p<0.01) from 1.7o prior to surgery to 4.0o and 4.3o at 12 and 24 months respectively.

Conclusion

Preliminary results of this study found the PEEK-on-ceramic disc replacement produced significant decreases in pain and function scores, which were maintained through the 12 and 24 month follow-up. Range of motion, disc height, and lordosis of the operated segment were significantly increased after surgery and maintained during follow-up. The values were similar to those reported in other FDA IDE trials for cervical TDR.

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