Olympus medical systems corp.(omsc) was informed from the user that the 3 instances of unexpected healthy mucosa shearing/tearing off by the single use distal cover.The first case, following an endoscopic retrograde cholangiopancreatography (ercp) the endoscope had been suctioned, and then on inspection in the cleaning room a lump of tissue was found in the distal end of the endoscope.The medical staff were notified and inspected it.But the medical staff did not feel need to perform the reprocedure to look for the patient's injury.The second case, the user found a small piece of tissue in the distal end of the endoscope after removing the single use distal cover prior to suctioning.It was mixed with stone debris retrieved by ercp which was with it and some blood and mucous.The user did not alert anyone as was unsure it was not stone debris and did not think it was particularly out of the ordinary.The third case, the evis 190 series duodenoscope was used to visualize the ampulla following a gastroscopy.When the endoscope was removed after the procedure there was 4 significant pieces of tissue embedded in the single use distal cover and around the forceps elevator channel.The tissue appeared like sheared off smooth mucosa.The longest piece was nearly 20 mm long when straightened out, and the 3 other pieces were about 3x5 mm.The user completed the procedure.There has not been any bleeding or pain issues for the patient and they were discharged home.The user had inspected the single use distal cover and could not see any visual defect or protruding plastic.The user facility did not provide other detailed information.According to the number of the adverse events, omsc is submitting three medical device reports.This is 2 of 3 reports.
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This supplemental report is being submitted to provide additional information.The subject device was not returned to any of olympus locations.Omsc reviewed the manufacture history (dhr) of the subject device and confirmed no irregularity.Since the root cause analysis has been completed in capa.According to capa, the mechanism of occurrence of this event has been found to be as follows.Pattern 1: procedure is started without noticing cracks in the tip cover during pre-use inspection.By performing the suction operation with the tip in close contact with the mucous membrane, the mucous membrane enters between the tip cover and the elevator.The endoscope was removed with the mucous membrane inserted between the tip cover and the elevator (the tip was adsorbed on the mucous membrane).The mucous membrane that has entered at the cracked part of the tip cover is excised, and a piece of mucous membrane remains in the tip cover.Pattern 2: procedure is started without noticing cracks in the tip cover during pre-use inspection.Although no suction operation is performed, the mucous membrane enters between the tip cover and the elevator due to the strong contact between the tip and the mucous membrane.The endoscope is removed with the mucous membrane inserted between the tip cover and the elevator (the tip is in strong contact with the mucous membrane).The mucous membrane that has entered at the cracked part of the tip cover is excised, and a piece of mucous membrane remains in the tip cover.Pattern 3: by performing the suction operation with the tip in close contact with the mucous membrane, the mucous membrane enters between the tip cover and the elevator.The endoscope was removed with the mucous membrane inserted between the tip cover and the elevator (the tip was adsorbed on the mucous membrane).The mucous membrane that has entered at the edge of the tip cover (around the u-shaped slit) is excised, and a piece of mucosa remains in the tip cover.In addition, the root cause has been identified as follows from the mechanism of occurrence.Structure: root cause 1: compared to conventional products, there is a space for mucous membrane to enter between the elevator and the tip cover.Root cause 2: compared to conventional products, the tip cover has an edge (around the u-shaped slit), and the edge is in a position where it can easily come into contact with the mucous membrane.Operation of the surgeon: root cause 3: start the inspection without confirming that the tip cover is properly attached during the pre-use inspection (start the inspection with the tip cover cracked).Root cause 4: removing the endoscope with the tip adsorbed on the mucous membrane by suction operation.Patterns 1 to 3 shown in the mechanism of occurrence occur when a combination of several root causes is aligned.Pattern 1: when the combination of root causes 1 to 4 is aligned.Pattern 2: when the combination of root causes 1 to 3 is aligned.Pattern 3: when the combination of root causes 1, 2 and 4 is aligned.Regarding the relationship of the device to the reported incident or adverse event, although the use of the device caused tissue damage, it was judged that no additional treatment was necessary.The mechanism of occurrence of health damage is as described in the above-mentioned "cause analysis" items.In addition, as described in the above "cause analysis" items, it is considered that there is no suspicion of usability problems.As a result of risk analysis of this event, it was found that the mdr report type is "malfunction".
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