The mayfield modified skull clamp (a1059) was returned for evaluation: device history record (dhr) - the dhr was reviewed and shows no abnormalities related to the reported failure.Failure analysis - investigation of the returned unit could not duplicate movement.However, the lock had both rotational and lateral movement and a residue buildup was present.Upon disassembly, it was also noted that the index knob and the lock needed new components added to replace worn internal parts; unit was machined to have heli-coils added to large starburst threads.New components were added to replace worn internal parts, and general cleaning and maintenance were performed.Root cause - evaluation found no device deficiencies that would have contributed to the reported complaint.The lock had a slight movement in it, but when properly positioned and put under pressure, it does not move.Probable root cause is improper or suboptimal placement of the skull clamp on the patient.No further investigation required based on the acceptability of risk and no adverse trends identified.This will be monitored and trended going forward.At present, we consider this complaint to be closed.
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