MHRA recalls the M6 artificial cervical disc
A recent safety alert issued by the Medicines and Healthcare products Regulatory Agency (MHRA), concerning the M6 artificial cervical disc (commonly referred to as the M6 vertebral disc replacement), updates patient monitoring guidance and raises serious concerns for patients with the medical implant.
What is the M6-C device?
The M6-C artificial cervical disc was designed as a motion-preserving alternative to spinal fusion surgery, intended to replicate the biomechanics of a natural intervertebral disc. In principle, such devices offer significant benefits, including reduced adjacent segment degeneration and preserved mobility.
However, what is increasingly apparent is that the risks associated with this device may not have been fully understood or adequately disclosed to patients receiving the implant.
The MHRA safety warning
In January 2026, the MHRA issued device safety information (DSI/2026/001) following an assessment of emerging evidence and adverse incident reports. The regulator identified:
- reports of osteolysis (bone loss) associated with the device;
- evidence of early device failure in clinical literature;
- a delay by the manufacturer in communicating updated risk information to UK users and patients.
Severe cases of osteolysis were often associated with complex revision surgeries including partial removal of vertebral bone (corpectomy).
As a result, the MHRA has now mandated active identification and recall of any patient with an M6-C device, mandatory ongoing annual radiological monitoring, even in asymptomatic individuals, and for patients to be given explicit warnings regarding the risk of osteolysis and potential complications.
This represents a significant shift from standard post-operative follow-up and strongly suggests that prior risk management was insufficient.
Osteolysis and the risk of catastrophic injury
Osteolysis is a progressive pathological process involving bone resorption around the implant. It can compromise the stability of the device and if left undetected, lead to serious complications. Clinical literature of the M6-C device has highlighted concerning rates of revision surgery linked to osteolysis. Of particular concern were cases where the condition was initially asymptomatic, resulting in delayed diagnosis and progressive bone loss leading to implant instability and failure.
In severe cases, this can result in spinal instability, nerve root or spinal cord compression, chronic pain and neurological deficit, and catastrophic spinal cord injury, including paralysis.
While paralysis is not inevitable, it is a foreseeable consequence in advanced untreated or undetected osteolysis, particularly where monitoring has been inadequate.
A critical feature of the MHRA’s findings is the delay in communication of known risks by the manufacturer Orthofix. Updated warnings regarding osteolysis were introduced internationally as early as 2020. The UK updates to the Instructions For Use (IFU) followed later in 2023 and a formal Field Safety Notice was not issued to UK users until August 2025, following which the product was withdrawn from the UK market.
The British Association of Spinal Surgeons has issued guidance mandating all patients with an M6-C implant to remain on active monitoring until further evidence becomes available regarding a suitable end date. Literature regarding the device failure rates found that revision was required between five to eight years post-index surgery, suggesting mandatory monitoring is likely to be required for a minimum of 10 years.
Patients with the implant are advised to seek a consultation with a spine surgeon if they have one or more of the following:
- increasing neck pain;
- increasing arm pain radiating from the neck to the arm or hand;
- pins and needles in the hands or arm;
- clumsiness or weakness in the hands or arm;
- electric type sensations into the arms or trunk on neck movements;
- increasing clumsiness and loss of balance of the legs.
Urgent appointments are required (within a maximum of two weeks) if a patient contacts their surgeon or healthcare provider with symptoms outlined above.
All patients (including asymptomatic ones) must be reviewed in a face-to-face appointment with an anterior-posterior and lateral X-ray of the cervical spine on an annual basis. If the patient reports symptoms and/or osteolysis is suspected, CT and MRI scans will be required to evaluate the implant further.
The intention of the monitoring programme is to ensure early investigation and identification of patients potentially at risk and to reduce the risk of serious and life-changing complications arising.