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Swiss prosecutors have launched an investigation into a failed spinal implant approved by UK regulators.

The total disc replacement implant made by Cambridge-based Ranier Technology left patients across Europe in agony and needing further surgery after breaking inside their backs.

Last month, BBC Panorama revealed how the Cadisc L implant was approved for use in humans despite evidence from studies in baboons that it could fail.

Ranier withdrew it from market in 2014.

Geoffrey Andrews, the founder and former CEO of Ranier told Panorama that the company has "scrupulously followed the procedures and standards required by all regulatory authorities".

The investigation

The prosecutors in Switzerland are investigating the circumstances in which the device was implanted into patients.

The hospital concerned has already launched a separate investigation.

A leading surgeon, Max Aebi, implanted the device into at least seven patients.

Mr Aebi was on Ranier's scientific advisory board and, according to minutes of meetings seen by Panorama, brushed off concerns raised by the animal studies.

At a meeting of the board at City Airport in 2009 Mr Aebi described the adverse findings of a review of the baboon study as "just a radiological review" which "does not have anything to do with reality".

Image copyright Melanie Schmidts Image caption An implant that was taken out of a patient after it broke

The report on radiological results on six baboons found "worrying changes between the implant and the bone in all but one subject".

Dr Karsten Ritter-Lang, a surgeon who has removed more than 70 of the failed devices from patients in northern Germany, told Panorama after seeing reports on one of the baboon studies that using the implant in humans was "crazy".

"If we have this in animal testing, you can never put this in humans."

Lawyers for Mr Aebi told the BBC that their client would "not comment until the investigation is completed".

Ranier withdrew the Cadisc L from the market in 2014 after 29 patients in the clinical trial were found to have had 32 adverse events, in six cases requiring the device to be removed.

No UK patients have been identified so far. It is understood that 90% of the devices were exported to Europe.

Panorama investigated the device as part of the Implant Files project, an international investigation of the medical implant industry organised by the International Consortium of Investigative Journalists (ICIJ). The global investigation involved 58 media organisations including BBC Panorama, the Guardian newspaper and the medical journal, the BMJ.

The Swiss prosecutors are likely to request information from UK-based regulators that approved the device. A clinical trial to test the device in humans was signed off by the British regulator, the Medicines and Healthcare products Regulatory Agency (MHRA).

The implant was approved for use across Europe following initial results from the trial by the British notified body, the British Standards Institution (BSI). But there are doubts whether either organisation was aware of the results of the baboon studies. The BSI said it "does not have any records of the baboon study".

The MHRA told the BBC: "In reviewing any application for a clinical investigation, we undertake a rigorous clinical and technical review of data supplied. Clinical investigations also must be approved by the Health Research Authority (HRA)".

The device failed to obtain approval for human use in the US.

Geoffrey Andrews, the founder and former CEO of Ranier, did not respond to requests to comment but told Panorama previously that the company has "scrupulously followed the procedures and standards required by all regulatory authorities".