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Please note correction to d4 (lot #).The reported event could be confirmed, since the device was returned for evaluation, and matches the alleged failure.The device inspection revealed the following: the drill was received and found broken at its tip and the broken fragment was not returned.Helix shaped marks observed on the periphery of the drill proximal to the broken tip indicating a torsional overload during usage.Microscopic view of the broken surface does not show any plastic deformation and is found smooth, which indicates a brittle failure of the material due to application of excess torsional force and bending.Furthermore, a hardness test according to rockwell on the returned item indicates the material being in accordance to the values in the material specification excerpts from the clinical assessment in a similar case an intra-operative breakage of a drill is a rare but common complication and well known to an experienced user.It is caused by twisting the drill and too much bending.Breakage caused by material defect is very rare in current manufacturing technology.It is of interest whether a broken part of a drill can be left in the bone or should be retrieved, also in the case that greater harm to the bone would be done.It is well known to an expert user that a broken part of a drill which is completely embedded in the bone normally does not cause any harm.In absence of a nickel allergy, the material used for the drill does not cause any local or systemic incompatibility.¿ therefore, no further surgical procedures in this special case are required.However, it lies in the responsibility of the treating surgeon to leave or to remove the broken off part.A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.A review of the labeling did not indicate any abnormalities.No indications of material, manufacturing or design-related problems were found during the investigation.Based on investigation, the root cause was attributed to a usage related issue.The event was caused by application of excess torsional force and bending resulting in a brittle failure.If any additional information is provided, the investigation will be reassessed.
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