The mayfield 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 - the reported complaint was confirmed from the evaluation.The skull clamp had rotational movement in its swivel lock assembly and a residue buildup was present.For the adjustment some worn-off internal parts must be replaced.To resolve all issues, the internal parts were replaced, and the skull clamp was carefully repaired according to the manufacturer's instructions.The swivel base rotates smoothly and has no movement when the index knob was in the locked position; the swivel lock closes and opens properly, and the index knob had a positive rollover.The skull clamp was subjected to a successful function test.Root cause - complaint is confirmed via inspection of the unit.There was movement in the swivel lock assembly and the unit required replacement of worn internal parts.Probable root cause is routine use and wear of the unit.Additionally, improper or suboptimal positioning of the skull clamp on the patient can contribute to movement of the patient.No further investigation is 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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