Artificial Disc Replacement Technologies
The Mobi-C cervical disc is one of the most widely used cervical discs in the world. First implanted in Orleans, France in November 2004, Mobi-C has been implanted in more than 17,000 spinal levels in 25 countries.
A total of 599 patients were involved in the Mobi-C U.S. clinical trial, which represents the largest concurrent clinical trial ever conducted for cervical disc replacement. Mobi-C received FDA approval in August of 2013, making it the first cervical disc with both one and two-level indications.
Mobi-C – How it Works
Mobi-C contains patented Mobile Core Technology™ that allows the polyethylene core to slide and rotate inside the disc for self-adjustment to the cervical spine movements. This means that Mobi-C can react to the normal motion in the cervical spine.
Mobi-C provides bone sparing fixation without chisel cuts into the small vertebral bodies of the cervical spine, making it safe for implantation at two levels.
Mobi-C – Clinical Trial Results
In the one-level study, Mobi-C demonstrated non-inferiority to ACDF as reflected in the primary composite endpoint. In the two-level study Mobi-C demonstrated SUPERIORITY to ACDF in the primary composite endpoint. Key results from the two-level study include:
- Overall trial success was 69.7% for Mobi-C and 37.4% for fusion, which represents statistical superiority(p< 0.0001).
- The rate of secondary surgeries at the operated level for Mobi-C was 3.1% versus 11.4% for fusion.
- The percentage of subjects who demonstrated adjacent segment degeneration (determined by x-ray) was:
- 2.9% of Mobi-C patients compared to 18.1% of ACDF patients at the inferior adjacent level
- 13.1% of Mobi-C patients compared to 33.3% of ACDF patients at the superior adjacent level
- Mean return to work time was 20.9 days shorter for Mobi-C patients compared to fusion patients.
- 78.2% of Mobi-C patients showed improvement in Neck Disability Index (NDI) based on the FDA success criteria versus 61.8% of fusion patients.
About ProDisc-L The ProDisc-L Total Disc Replacement device is intended to treat a single degenerated (diseased) disc in the lower spine (L3-S1). The ProDisc-L implant was designed in collaboration with practicing spine surgeons and has been thoroughly tested in both laboratory and clinical settings.
The ProDisc-L implant allows the potential for motion through its ball and socket design.
- A plastic inlay affixed to a bottom metal endplate forms the ball.
- A polished concave metal surface in the top endplate forms the socket.
- The socket can move over the surface of the ball to allow for controlled and predictable motion.
The ProDisc-L implant is secured to the bones (vertebrae) in the spine with a patented central keel on the top and bottom endplates. A coating has also been applied to all the implant surfaces that contact bone to allow for the bone to grow onto the implant.
The ProDisc I implant, the predecessor of the ProDisc-L implant, was first implanted in 1990. The ProDisc-L implant that is used today was introduced outside the United States in 1999. It was approved by the Food and Drug Administration (FDA) for use in the United States in August 2006.
A ProDisc-L IDE clinical study evaluated the ProDisc-L Total Disc Replacement surgery compared to spinal fusion surgery*. The study demonstrated that ProDisc-L surgery is a safe and effective alternative to fusion surgery* for qualified patients.
For more information about the ProDisc-L implant and procedure, please refer to the resources provided on the right. This information is not a replacement for professional medical advice. Only your surgeon is qualified to diagnose and treat your condition. *The ProDisc-L surgery was compared to a “Circumferential” fusion surgery, which involves removing the diseased disc and inserting a disc spacer through an incision in the abdomen and attaching metal screws and rods to the back of the spine through incision(s) in the back.
About ProDisc-CThe ProDisc-C Total Disc Replacement device is intended to treat a single degenerated (diseased) disc in the upper spine (C3-C7). The ProDisc-C implant was designed in collaboration with practicing spine surgeons and has been thoroughly tested in both laboratory and clinical settings.
The ProDisc-C implant allows the potential for motion through its ball and socket design.
The ProDisc-C implant is secured to the bones (vertebrae) in the spine with a patented central keel on the top and bottom endplates. A coating has also been applied to all the implant surfaces that contact bone to allow for the bone to grow onto the implant.
The ProDisc-C was developed using the same design principles as the ProDisc-L implant. The first ProDisc-C Total Disc Replacement surgery was performed in Europe in 2002. It was approved by the Food and Drug Administration (FDA) for use in the United States in December 2007.
A ProDisc-C IDE clinical study evaluated the ProDisc-C Total Disc Replacement surgery compared to spinal fusion surgery*. The study demonstrated that ProDisc-C surgery is a safe and effective alternative to fusion surgery* for qualified patients. For more information about the ProDisc-C IDE Study, refer to the ProDisc-C IDE Study Brochure and talk to your doctor.
This information is not a replacement for professional medical advice. Only your surgeon is qualified to diagnose and treat your condition.
*The ProDisc-C surgery was compared to an ACDF surgery, which involves removing the diseased disc and inserting a spacer into the space through an incision in the front of the nexk. A plate and screws are attached to the bones in the front of the spine to hold the spacer in place and to help promote fusion.
Spinal Surgery – Know your options
Total Disc Replacement surgery with ProDisc is different from traditional spinal fusion surgery. Both surgeries are intended to relieve pain by removing the diseased disc and restoring the height of the affected disc space.
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.
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.