The suspect device was returned to olympus for evaluation.During inspection, the cutting (knife) wire was confirmed to be broken and the broken portion was scorched and melted.When the outer diameter of the cutting wire was measured, there was no abnormality identified.It was also confirmed that there was no problem with the length of the cutting wire and and the length of the coated portion of the cutting wire.It was also confirmed that there were no missing parts in the subject device.There were no defects identified with the device that could have caused the breakage of the cutting wire.A review of the device history record found no deviations that could have caused or contributed to the reported issue.The device met all specifications at the time of shipment.Based on the results of the legal manufacturer's investigation, although a definitive root cause could not be identified, it is likely the issue was due to the output being activated while a torn area of the coated portion of the cutting wire came into contact with the distal end of the endoscope while the forceps elevator was raised, causing the cutting wire to become instantly hot, resulting in the wire breaking.Based on the results of the legal manufacturer's investigation, it is likely the coated portion was torn due to the forceps elevator being raised.Then, when the cutting wire deflected, the coated portion of the cutting wire and the metal part of the distal end of the endoscope came into contact.The cutting wire moved back and forth, causing the coated portion of the cutting wire to tear.The slider was pushed more than needed, causing the cutting wire to deflect.The device's instruction manual provides the following warnings which may help to prevent the issue: "since the cutting wire is very thin, it may break off in the following cases: the distance between the papilla of vater and the cutting wire is very short, the output is too high or activated while the cutting wire touches metal parts of the endoscope, or the cutting wire is tightened too strong.When the cutting wire breaks off, its proximal end will be retracted toward the endoscope if the slider is pulled.If the slider is pushed, the cutting wire will be pushed out toward the papilla or move sideways.If the cutting wire breaks off, stop the output immediately and pull the slider completely to retract the broken cutting wire into the tube.Then withdraw the sphincterotome from the papilla.Otherwise, patient injury, such as perforations, bleeding, or lacerations within the biliary duct, and/or damage of the endoscope could result"."when inserting the instrument into the endoscope, be sure that the cutting wire is parallel to the tube.Otherwise, the metal part of the forceps elevator may contact the cutting wire and peel off the coating material"."do not activate output while tissue is in contact with the torn or damaged coated portion of the distal end.If output is activated while tissue is contacting the torn or damaged coated portion due to insertion into or withdrawal from an endoscope, leakage current, decreased output, and/or thermal injury could result"."if you feel the cutting is blunt, withdraw the device from the scope to examine if there is any peel off and tear at the coating portion".Olympus will continue to monitor field performance for this device.
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