Positive two-year data released for the M6-C cervical disc


Orthofix Medical today announced the full two-year outcomes from its US Investigational Device Exemption (IDE) study of the M6-C artificial cervical disc (Orthofix).

Jack Zigler, orthopaedic spine surgeon at Texas Back Institute (Plano, USA) and an investigator in the study, presented the study results during the International Society for the Advancement of Spine Surgery annual meeting (3–5 April, Anaheim, California).

The data demonstrates that patients treated with the M6-C artificial cervical disc had significant improvements in neck and arm pain, function and quality of life scores. Additionally, these patients had a significant difference in the reduction of pain and opioid medications use when compared to anterior cervical discectomy and fusion (ACDF) patients. At 24 months, patients in the ACDF group who were still using pain medications had a seven times higher rate of opioid use than those in the M6-C disc group.

“The results from the M6-C artificial cervical disc IDE clinical study continue to validate the positive outcomes of cervical disc arthroplasty versus discectomy with fusion,” said Zigler. “A significant reduction in pain, the maintenance or improvement of neurological function, and the preservation of natural disc motion after 24 months were all meaningful clinical benefits the M6-C disc patients experienced when compared to the fusion control. Additionally, patients receiving the M6-C disc were able to significantly lower their use of NSAIDs—and more importantly—significantly lower their use of opioid medications.”

A prospective, non-randomised, concurrently controlled clinical trial, the M6-C IDE study was conducted at 23 sites in the USA with an average patient age of 44 years. The study evaluated the safety and effectiveness of the M6-C artificial cervical disc compared to ACDF for the treatment of single level symptomatic cervical radiculopathy with or without cord compression. The overall success rate for the protocol-specified primary endpoint for the M6-C disc patients was 86.8 percent at 24 months and 79.3 percent in the control group. This data statistically demonstrates that cervical disc replacement with the M6-C disc is not inferior to treatment with ACDF.

Secondary outcomes at 24 months include:

  • Patients who received the M6-C disc demonstrated statistically significant improvement in the Neck Disability Index as measured at week six and months three, six, 12 and 24.
  • Meaningful clinical improvement was seen in the following pain scores:
    • 91.2% of patients who received the M6-C disc reported an improvement in neck pain compared to 77.9% in patients who underwent the ACDF procedure.
    • 90.5% of the M6-C patients reported improvement in arm pain scores compared to 79.9% in ACDF patients.
  • Prior to surgery, 80.6% of the M6-C disc patients and 85.7% of the ACDF patients were taking some type of pain medication for the treatment of their cervical spine condition. At 24 months, the rate of M6-C patients who were still taking some type of pain medication dropped to 14% compared to 38.2% of the ACDF patients.
    • Of these, there was a seven times higher rate of opioid use with the ACDF patients than with patients who received the M6-C disc.
  • There was a statistically significant difference in the average mean surgery time—74.5 minutes for patients receiving the M6-C disc versus 120.2 minutes for those patients having the ACDF procedure.
  • In addition, there was a statistically significant difference in the mean length of hospital stay—0.61 days for the M6-C patients versus 1.1 days for ACDF patients.
  • Subsequent surgery at the treated level was needed in 4.8 percent of the ACDF patients compared to 1.9 percent of the M6-C disc patients.
  • There were no device migrations reported in the study.
  • Overall patients receiving the M6-C disc reported a 92% satisfaction rate with the surgery, and 93% said they would have the surgery again.
  • There were 3.8% serious adverse events related to the device or procedure in the M6-C disc group versus 6.1% in the ACDF group.

The M6-C disc received US Food and Drug Administration (FDA) approval in February 2019 based on the results of this study.

“With the recent FDA approval of the M6-C artificial cervical disc, we are excited to be able to provide spine surgeons and their patients a new and innovative alternative to the ball-and-socket artificial disc designs currently available in the USA,” said Global President of Orthofix Spine Brad Niemann. “What makes the M6-C disc so unique is its physiologic single-piece design featuring an artificial nucleus and annulus that work together to mimic the biomechanical motion of a natural disc to include axial compression or shock absorption, which no other disc available in the USA has to offer.”


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