1.Description of adverse event: dat clip - misfire.Emr performed - dat clip used to try to close resection site.Regular technique used to close clip caused maldeployment of clip.Clip was unable to be removed.Clip was left inside the patient but it was closed.2.Internal investigation of adverse events: based on the description of adverse event, we conducted investigation and analysis from aspects such as structural design, raw materials, production processes, technical standards, and inspection methods.The investigation and analysis are as follows.2.1 structural design.The working principle of clip is as follows: the effective length of the clip enters the endoscope cavity, and the clip assembly contacts the mucosal tissue.The outer tube and the endoscope contact the spring tube and clip assembly, which are mechanically connected.The two sliding blocks of the handle are connected to two wires, and the corresponding clamp pieces are controlled separately.The force is transmitted to the clip to achieve opening and closing, and the repeated opening and closing performance is achieved through the slide groove of the clip, utilizing the self-locking structure of the clip itself, close and separate the clip from the outer tube to complete the release of the clip.The function of clamping tissue is achieved by utilizing the self-locking structure of the clip itself to close the clip and squeeze the tissue, therefore this performance is related to the structure of the front-end clip assembly.The self-locking structure relies on the force exerted on the tail of the clip to be pulled into the clip pedstal, which restricts the movement of the clip.After the clip takes out the tissue, the tail entering the clip pedsta is restricted to achieve clip locking.The structural characteristics and working principle of the clip itself can ensure that the clip can effectively clamp the tissue after clamping, without the phenomenon of detachment.2.2 raw materials.The component used to achieve clamp closure is the clip assembly, which is made of stainless steel material.The material strength and hardness can meet the requirements for the clipp to remain closed after closure without being supported by the tissue.And we have checked the inspection batches of the raw materials for the clip, and found that the raw materials meet the requirements.The appearance and dimensions of other measurements are also qualified and stored after inspection.2.3 technical standards.2.3.1 clamping force: the clamping force should not be less than 0.6n.We have reviewed the production records (dhr) and determined that the clips were executed in accordance with the operating and inspection procedures.The clamping force indicators are also consistent with the technical requirements.Therefore, we confirm that the batch of products as a whole meets the requirements.2.3.2 release force: slowly pull any slider towards the bracelet until the clip is closed, and continue to pull the slider towards the proximal end.The clip should release smoothly, with a release force of less than 150n.2.4 inspection methods.2.4.1 clamping force inspection method: slowly push the two sliders on the handle towards the far end to open the two clips.Use either side of the clip to align with the thin line and 1.0mm thick silicone film.Slowly pull the two sliders towards the bracelet to clamp the thin line and silicone film, and continue to pull the two sliders towards the bracelet until the clamp seat and support seat separate.After completing the clamp release action, place the silicone film on the upper clamp of the tension machine, place the fishing line on the lower clamp, set the tension machine speed to 50mm/min, start the test, until the clamp and silicone film detach, and record the tension value.The clamping force performance of the clamp is related to the clamping ability of the clamp.During the design and development stage of the clamp, a detailed analysis was conducted to transform the performance of the clamp clamping organization into technical specifications that can ensure the safety and effectiveness of the product.The inspection method of clamping force testing was used to identify potential design faults.At the same time, there is a large amount of clinical data to prove that the setting of clamping force testing methods can objectively meet the expected use of the product's clamping tissue.Therefore, we confirm that the setting of the clamping force testing method can objectively meet the requirements of the clamping performance of the clamp, and there is no problem with the setting of the inspection method.2.4.2 release performance testing method: fix the fixture on the upper end of the tension machine, place the slider on either side of the handle on the fixture, with the bracelet facing up and the outer tube facing down.Fix the outer tube on the lower end of the tension machine, set the speed of the tension machine to 200mm/min, and start the test until the clamp component disengages from the support seat.Record the maximum force value during the pulling process.In the early validation stage, we have passed a large amount of clinical data to prove that the release performance setting can objectively meet the product performance requirements, and the technical standard setting is ok.Summary: based on customer feedback on clip misalignment, we have investigated and found no abnormalities in structural design, raw materials, production process, technical standards, inspection methods, etc.The cause of this adverse event has not been found yet.We will keep monitor on such issues.
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