The manufacturer did not receive devices, x-rays, or other source documents for review.As no lot numbers were provided for the devices, the device history records could not be reviewed.As the case at hand was taken from a journal article it is not suspected that the device or additional information is being submitted for review.However, additional information has been requested and is not currently available.A cause for this specific event cannot be ascertained from the information provided.Should additional information become available and an investigation result be available, that changes this assessment, an amended medical device report will be submitted.Zimmer's reference number of this file is (b)(4).
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It was reported in a journal article that 50 dynesys operations in (b)(6) patients were performed between (b)(6) 2002 and (b)(6) 2008.One patient was revised on an unknown date due to screw loosening and migration (l3 right, l5 bilateral).(journal article: late infections after dynamic stabilization of the lumbar spine with dynesys - jon a.Lutz, philippe otten, gianluca maestretti).
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As for zimmer specialists to perform an in-depth analysis it is required to have all necessary information at hand, it was therefor tried to receive more information for this case.Trend analysis: was not possible to perform, as no item number was available.Device history records (dhr): as no lot numbers were provided for the devices, the device history records could not be reviewed.An e-mail requesting missing device data information was sent.At zimmer (b)(4) all medical devices prior release to market undergo several quality inspections as defined in our quality procedures.Our quality inspection- and deviation procedures ensure that only products fulfilling the specification are sold.These procedures are part of the overall quality management system at zimmer (b)(4) and get regularly audited by our notified body, competent authorities and internal and external auditors.Thus, for all products sold to the market can be assumed having a complete and correct dhr.Event summary: in the journal article "late infections after dynamic stabilization of the lumbar spine with dynesys" it is reported, that a patient underwent revision surgery due to dynesys screw loosening (l3 right, l5 bilateral) and implant migration.Review of received data: review of the journal article "late infections after dynamic stabilization of the lumbar spine with dynesys".No medical data such as x-rays, surgical notes or any other case-relevant documents were received.Devices analysis: no product was returned to zimmer biomet for in-depth analysis.Review of product documentation: no product documentation was reviewed for investigation.Root cause analysis root cause determination using dfmea: - metallosis, loosening due to wear due to incorrect implantation - possible: it is unknown, whether the surgeon was following the surgical technique of the device.Wear was not reported.However, loosening due to wear can not be excluded.Loosening is a known risk and mentioned in the ifu of the device implanted.- screw loosening due to wrong selection of pedicle screw size - possible: the combination and sizes of the implants used is unknown.Therefore it can not be excluded that the wrong pedicle screw size was used.- screw loosening due to too fast dissolution -> new bone is not fast enough to bridge the space of the dissolved ha coating - possible: test concerning chemistry and solubility, morphology, shear and tensile tests were performed and documented.Insertion and removal tests with analysis of insertion / removal torque and ha wear debris were performed and documented.However, it can not be excluded that the bone was not fast enough to bridge the space of the dissolved ha coating.- screw loosening or breakage due to bone ¿ implant interface is not strong enough - possible: it can not be excluded that the bone - implant interface was not strong enough.Patient bone quality is unknown, x-rays were not received for review.However, ha coating improves osseous integration and induces more bone formation and faster mineralization.Further ha allows for earlier bone integration and was tested, results are documented.Conclusion summary: due to significant lack of information, it is impossible to perform a meaningful analysis of the reported event.However, poor bone quality favors loosening of the screw as the implant would dissolve too fast in patients bone.Neither surgical approach nor x-rays were shared.The screw sizes implanted are unknown, therefore an exact root cause could not be determined.The need for corrective measures is not indicated and zimmer (b)(4) considers this case as closed.(b)(4).
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