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1.Information indicates that on (b)(6) 2021, during an ercp, the tech was trying to deploy the duraclip and it was stuck and very hard to deploy.They really pulled it tight and it deployed along with the inner metal shaft.The doctor had to fish the long metal piece and clip out of the patient with a net/snare.The entire clip will be returned for review.Other clips from same lot number were used in the same procedure with no issues.It is noted the procedure was successfully completed with no alternate device used.There is no indication of impact or injury to the patient.2.Internal investigation of adverse event: the device was not returned to mt for evaluation.The customer provided the complaint product photos.It can be seen from the complaint photos that the welding position of the drive wire is broken.Regarding the breakage of the drive wire welding position, we have conducted the following investigations from the aspects of product release principle, raw materials, production process, inspection, use method, etc.2.1 product release principle: first we introduce the release principle of the clip: the rear end of the pull hook is connected with the drive wire and the handle, which is connected with the clip through the pin roll.It is the driving part by providing push/pull force to the clip.The chute on the clip moves around the point i under the action of the push/pull force.The pin roll moves to realize the opening and closing and release of the clip.At the same time, the three claws of the grip hook are inserted into the holes of the outer tube assembly and the clip pedestal to ensure the connection between the clip pedestal and the outer tube assembly in the non-released state.The position tube is installed in the grip hook.When the pull hook is pulled back and the clip is closed, the plane of the tail of the pull hook abuts against the position tube to limit the further withdraw of the pull hook and prevent the hook of the clip tail from hanging on the clip pedestal platform and close the lock in advance.After the clamping is completed, it continues to pull the handle back.At this time, the pull hook will transmit the back pull force to the grip hook through the resisting position tube.The three claws of the grip hook are deformed by force.Disengage from the hole to realize the first separation action, that is, the separation of the clip pedestal and the outer tube assembly.After the three claws are disengaged from the clip pedestal and the hole of the outer tube assembly, the clip can continue to withdraw, driving the clip to further close and lock, and the tail hook of the clip hooks on the platform of the clip base to realize the self-locking of the clip.Continue to pull the handle back.At this time, the clip has been restricted by the pin roll at point i and cannot continue to withdraw.After the hook of the pull hook bears the tensile force to its strength limit, the hook is deformed, and the notch at the front end becomes larger due to the deformation, making the pin roll fall off from it, and the second separation action is realized, at which time the clip is completely deployed.All of the above operations need to connect the steel wire through the handle, and finally transfer the force to the clip to release it.When the tip angle is relatively limited, the force cannot be transferred to the clip.Continuous application of greater force may lead to the welding position of the drive wire and the steel wire in the picture.Fracture.This risk has been identified in the product design stage.The internal production process monitors the release force and welding position tensile force.The average release force of this batch is 64.42n, which meets the requirements.This batch produced a total of (b)(4) pcs, during which a total of 8 tensile force monitoring was performed, and each test was (b)(4) pcs.The minimum value of the tensile force result was 152.10n, and all the results are in line require.(b)(4).2.2 raw materials: the material of the drive wire is (b)(6).Check the inspection record of this batch of drive wires, which meets the requirements of the drawings.The material of the drive wire has not changed, and we have fully verified the drive wire in the preliminary design to confirm that the dimensional performance of the drive wire can meet the requirements of use.(b)(4).Therefore, it can be confirmed that the selection of drive wire materials can meet the requirements of use.We query dhr according to the batches reported by the customer complaint.During the production process, the tensile force test of the cable assembly welding meets the standard.The inspection records of the raw materials of the caulking tube are also qualified of warehousing.We simultaneously checked the remaining production batches produced by the inspection batch of the caulking tube and the remaining production batches that went through the same process on the same day, and there was no abnormality in the production.Therefore, the functional failure is not caused by the material.2.3 production process it can be seen from the picture that the fracture position is the welding position of the caulking tube and the drive wire.The operation steps of our production process are as follows: (1) first thread the drive wire into the caulking tube (2) then insert the caulking tube into the tooling, push the drive wire forward to the end, and confirm whether the caulking tube is in place (3) after adjusting the position of the solder joints, align the edge of the caulking tube with the marking position (4) step on the circle welding switch, 100% of the welding process is checked by the welder's ccd monitor, and the welded joints of the caulking tube are not allowed to have insufficient welding spots, wrong wires, leaks, etc.During the production process, we will conduct the first and final inspections and the tensile force monitoring every 2 hours, and the machine will also be confirmed annually to ensure the stability of the welding.Inquiry about dhr welding machine number of this batch is (b)(4), the machine confirmation report file number is: (b)(4).(b)(4).2.4 inspection: 2.4.1 welding force of caulking tube and drive wire: make a sample and use a tensile machine to test.The upper and lower clamps of the tensile machine are at a distance of 75mm, and the speed is 200mm/min.The tensile machine clamps the stainless steel wire and the drive wire separately, records the tensile force, and the tensile force is required to be not less 80n.After inquiry, this batch produced (b)(4) pcs.Welding started on february 7, 2021 to the end of welding on february 8, 2021.During this period, a total of 8 tensile force were monitored.Each batch was tested with (b)(4) pcs, and the minimum tensile force was 152.10n.2.4.2 release performance: the distance between the upper and lower clamps of the tensile machine is 250mm, the speed is 200mm/min, the proximal spring tube coil is two turns (d is about 200mm), the handle is fixed to the auxiliary tooling, and the fixture is fixed to the upper clamp of the tensile machine, and the lower clamp clamps the proximal spring tube.Start the tension machine until the clip is released (the clip assembly should be smoothly separated from the transition cap), note the release force, and observe that the clip should be completely closed.The release force is required to be f not more than 100n, and the average release force of this batch is 64.42n.For the release force test, we randomly select 5pcs from the assembled products for testing.Therefore, no abnormality was found in the test records of the welding force and release force of this batch of shim pipes and cables.(b)(4) the weld fracture occurred for the first time, so there is no problem with the setting of the inspection method.2.5 use method: duraclip passes through the endoscopic biopsy path to reach the patient, gently move the distal slider to open the clip, close the clip at the desired location, and move the slider to the proximal end to close the clip.Analysis: combined with the analysis of past customer complaints, during the operation, the front end of the clip needs to be inserted into the endoscopic biopsy channel.When the front end angle is relatively extreme, the front end of the product will bend.When the operator pulls the handle to release, the force is concentrated on the drive in the middle of the line, the force value cannot be transmitted to the front end release position, and more force is continuously applied.When the force value reaches a certain value, the welding position of the drive wire and steel wire in the video may be broken.3.Summary: according to the complaint pictures, we have conducted investigation and analysis in terms of product release principle, raw materials, production process, inspection, and use methods (past customer complaints).The possible cause of this customer complaint is that the medical staff are performing surgery and are in the position in special cases, the front end angle limit will cause the front end of the product to bend.When the operator pulls the handle to release, because the force is concentrated in the middle of the drive line, the force value cannot be transmitted to the front end release position.When the force value reaches a certain value, it may cause the complaint occurs.In response to this phenomenon, we recommend: (1) when the front end of the endoscope needs to bend the hook head, the bending position should not be pressed against the junction of the clip pedestal and the transition cap assembly as much as possible; (2) if the endoscope is bent at the distal spring tube, try not to bend the product to 90 degrees, and it can be adjusted within 45 degrees.We will continue pay attention to this issue to ensure the patient safety.
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