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This report is being supplemented to provide additional information based on the legal manufacturer's final investigation and device evaluation.Corrections: b5 of the initial report; please see b5 for additional information.D10 (inadvertently left blank on the initial report).H8 from "reuse" on the initial report to "initial use of device." the device was returned to olympus for inspection, and the reportable malfunction was confirmed.A review of the device history record found no deviations that could have caused or contributed to the reported issue.Based on the results of the investigation, the likely mechanism causing the tip detachment may be the following: 1)due to the factor described below, spark discharge between the tissue and the electrode occurred during output activation.The high-frequency output was set too high.The electrosurgical unit was used in the coagulation mode.The output activation time was too long.2)high heat caused by spark discharge was locally applied to the tip and the electrode.This caused the adhesive strength of the adhesive agent which affixes the cutting knife and the tip to decrease.3)a force to perform tissue incision was applied to the tip.Due to the description stated above 2, the adhesive strength of the adhesive agent decreased causing the tip detachment.However, a definitive root cause was not determined.The event can be detected/prevented by following the instructions for use which state: when the electrosurgical unit is used in the coagulation mode, crack/detachment of the tip and the electrode or deformation/break of the cutting knife could occur, for example when the high-frequency output is set too high or the length of the contact between the cutting knife and tissue is too short.During treatment, always ensure that the slider slides on the handle smoothly and that the electrosurgical knife observed in the endoscopic image is normal.Should cracks or detachment of the tip or deformation/break of the cutting knife be detected during use, immediately shut off the power supply, discontinue the procedure, pull the slider and withdraw the endoscope from the patient with the cutting knife retreated in the insertion portion of this instrument.Do not continue using an abnormal electrosurgical knife to prevent perforation or hemorrhages.If the tip or cutting knife is detached be sure to collect it using grasping forceps.Aspirate fluids such as mucus that adhere to the electrode and/or the cutting knife, outer sheath and body cavity tissues.Patient injury such as punctures, hemorrhages, mucous membrane damage and thermal injury of tissue could result if output is activated when in contact with these adhering fluids.When current is discharged while the cutting knife is being separated from the mucosa under wet situation, it may break the cutting knife or crack the tip.Always operate the electrosurgical unit at the minimum output level and for the minimum time necessary to successfully complete the procedures.Excessive output level and time may result in patient injury, such as punctures, hemorrhages or mucous membrane damage.Application of high-voltage waveforms for extended periods increase the likelihood that it may break the cutting knife or crack the tip.When a high-voltage waveform has to be used, minimize the duration of current application.Olympus will continue to monitor field performance for this device.
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