U.S. Clinical Study Information
The PCM® Cervical Disc was studied in a prospective, multicenter, randomized FDA-approved investigational device exemption (IDE) clinical trial conducted in the United States to evaluate longitudinal outcomes over 2 years comparatively between the PCM Cervical Disc and anterior cervical discectomy and fusion (ACDF) with allograft and plate. A total of 416 patients with a degenerated cervical disc at one level from C3-C4 to C7-T1 were enrolled in the clinical trial and 403 were treated. Patients were randomly assigned to be treated either with the PCM Cervical Disc or ACDF.
Patients were evaluated before surgery, during the operation, immediately after surgery, and then at 6 weeks, 3 months, 6 months, 12 months and 24 months, and yearly after surgery. The patients were recommended to have a physical therapy program for non-impact exercises and active range of motion exercises after surgery. Patients were also instructed to avoid repetitive cervical flexion and extension bending and lateral bending and rotation for 6 weeks following surgery.
The safety of the PCM Cervical Disc was assessed by comparing the adverse events, any additional surgical procedures, and the neurological outcomes to those in the ACDF control group. The effectiveness of the PCM Cervical Disc was assessed by evaluating patients’ pain and function outcomes using a standard questionnaire, the Neck Disability Index (NDI), the severity of neck and arm pain based on a Visual Analog Scale (VAS) assessment, quality of life using a standard questionnaire, the Short Form-36 (SF-36), as well as a patient satisfaction questionnaire compared to the ACDF control group.
In addition, the patients were evaluated using radiographic evaluations, including spinal range of motion, spinal disc height, device displacement or migration, spinal fusion status, and heterotopic ossification (abnormal bone formation).
In the study, the average patient age was 45-years-old and 52% of the patients were men. Before surgery, approximately 80% of patients had symptoms of radiculopathy (a pathologic condition of the nerve roots) and approximately 19% had both radiculopathy and myelopathy (a disease or disorder of the spinal cord) symptoms.
The primary endpoint of the IDE trial was a composite measure termed “overall success,” which was evaluated at 24 months postoperatively, and was defined as at least 20% improvement in neck disability index (NDI) from preoperative score; absence of reoperation, revision, or removal; maintenance or improvement in neurological status; and absence of radiographic or major complications during the 24-month follow-up period. At the 24 months, overall success was achieved by 75.1% of the PCM patients compared to 64.9% of the ACDF patients.
In the U.S. clinical study of 214 patients who received the PCM Cervical Disc, the most commonly reported device or surgery related adverse events included neck and arm pain 2.3% (5 patients), incision site complications 5.6% (12 patients), dysphagia/dysphonia 5.1% (11 patients), and implant loosening or dislodgement 2.3% (5 patients). In addition, 6.0% (13 patients) required removal of the PCM device and 1.4% (3 patients) required reoperations. There may be other risks associated with using the PCM Cervical Disc. Of the 190 patients that were treated with ACDF, the most commonly reported device or surgery related adverse events included neck/arm pain 16.8% (32 patients), adjacent level disease 14.2% (27 patients), dysphagia/dysphonia 12.1% (23 patients), nonunion 5.8% (11 patients), and neurologic 5.3% (10 patients). Although many of the major risks are listed in this patient information webpage, more comprehensive safety information is provided in the physician’s package insert for the product. Please ask your doctor for more information and an explanation of these risks.
Complete information will be available in the PCM PMA Summary of Safety and Effectiveness Data (P100012) at www.fda.gov.
Other Clinical Resources
The growing body of evidence supports the fact that in well-selected patients, cervical arthroplasty is at least as successful (defined in several clinically meaningful ways) as the “gold standard” treatment of ACDF and may indeed offer advantages. Historic FDA-approved randomized, multicenter IDE clinical trials comparing cervical arthroplasty to ACDF were designed as non-inferiority clinical trials. These trials, conducted with the goal of FDA product approval, used more stringent success criteria than the historical ACDF studies and yet each individually showed at least non-inferiority of cervical arthroplasty compared with fusion. However, individually, the trials were not statistically powered to demonstrate a statistically significant improvement in clinical outcomes or “superiority” of one procedure over the other. A recently published paper using a meta-analysis was performed to pool the data from four approved cervical arthroplasty devices, including the PCM Cervical Disc, in an attempt to improve the statistical strength of the analysis.¹ The results of this meta-analysis suggest that for the common indications studied (1-level cervical disc degeneration with radiculopathy and/or myelopathy), cervical arthroplasty is not statistically different from ACDF in NDI success (15-point improvement from baseline) but is statistically superior to ACDF in the overall success (a composite risk-benefit endpoint), neurological success (maintenance of improvement neurological status from baseline) and survivorship (absence of revisions) outcomes 24 months postoperatively.
- McAfee PC, Reah C, Gilder K, Eisermann L, Cunningham B. A Meta-Analysis of Comparative Outcomes Following Cervical Arthroplasty or Anterior Cervical Fusion: Results From 4 Prospective Multicenter Randomized Clinical Trials and Up to 1226 Patients. Spine;2012, 37:943-952.
Read the full, published meta-analysis paper in Spine by clicking below.