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It was reported that the adapter disconnected from the prosthesis when tunneling under the prosthesis.This occurred with two units from the same lot.Additional information provided indicated that the application was vascular access, implantation site was the arm, the clear cover (sheath) was not removed before attempting to tunnel the graft, and that the doctor did not try to twist or turn the graft while tunneling.It was noted ¿shortly before pulling out approx.2-3 cm beforehand, the connector and the extension piece of the prosthesis were torn¿.The product was returned for evaluation.Grafts manufacturing engineering (me) examined customer returned unit and determined that the swivel rod, slider separated from the swivel rod, core.It was noted that crimp marks were present on the swivel rod, slider.It remains unknown what force or if excessive force was used during the tunneling procedures.It is noted that the only two events for this issue in the past 42 months occurred at the same facility.Based on the evaluation the scope of this investigation is limited to lot number (ln) 464990.The documentation for ln 464990 indicates visual/functional inspections of the gds met acceptance criteria.Measurements of the customer returned gds units from ln 464990 indicate that the components met dimensional requirements.There were no related customer complaints or non-conformances within the past 42 months.Additionally, units from other lots built on the same shift as the affected lot passed the gds pull out (tensile) test with values above the 8 lbf specification as defined in dd004218 ¿ flixene grafts product requirements (rev 07) product requirement (pr) 6.2.26.Pn 25126, ln 464990, consists of ten units (serial numbers 464990001 to 464990010).The two affected units consist of 20% of the lot (2/10 units).As of 26may2021, no units of ln 464990, pn 25126, were in atrium control.Per (b)(4), attaching gds (graft deployment system) (rev 04) the process failure of swivel rod not fully crimped may result in the severity 4 hazard of component separation inside body.This can be caused by the air pressure being set too low or air pressure malfunction/not calibrated.Process controls for air pressuring being set too low include equipment pre-set with air pressure and instructions in mp000753 to verify the air pressure is set to minimum of 80 psi.Process controls for malfunction/calibration issue include preventive maintenance and calibration of equipment.Control in-place for both process failures is a 100% function inspection per (b)(4) quality procedure qp, graft finished assy, inspect gds assembly revision bb.Method review: dd004218 ¿ flixene grafts product requirements (rev 07) product requirement (pr) 6.2.26, gds pull strength, states that the slider shall not break off from graft during implantation.The minimum tensile force at which the gds system fails or separates from the graft shall be 8 lbf.This pr was verified and is documented in dd019192-001 ¿ design verification report¿ gds anchor slider tooling move (rev 00).Tp000408 ¿ tp, graft finished assy, gds pullout (rev aj) is the method for measuring the force to pull the gds equipped assembly out of its anchor fitting on the graft.This method is performed during design verification testing only.Method validation is documented in dd002340-001 ¿ report, method validation by analysis of variance - gds graft pullout test (rev 00).Tp000408 (rev aj) contains a failure mode associated with crimp failure.Dd019192-001 (rev 00) which was used to support the product requirements indicates the minimum value of 51.39 lbf and maximum value of 62.98 lbf and with failure modes of ¿gds assembly failure¿ and ¿graft failure¿ were seen during the validation.The process of crimping in mp000753 (rev az) was reviewed.Procedure says to advance the small diameter of the swivel rod, slider into the slider crimping vise until it cannot be advanced further.The foot pedal on the slider crimping vise is fully depressed once and released.Procedure notes to observe the closure of the crimping dies in the vise, if they do not close, contact manager or designee.All crimped swivel rods are visually and physically examined to ensure they are mounted securely and spin freely.There is a check box on the dhr to indicate that the functionality was confirmed.The inspection process in qp000396 (rev az) was reviewed.All gds attachments are functionally inspected for swivel engagement.A 500 gram (1.1 lb) weight is attached to the weight hanger on the swivel rod, slider.The swivel must not disengage or damage.Quality engineering is contacted for non-conformance review (ncr) evaluation if issues are noted.Material evaluation: swivel rod, slider ln 465494, pn 000332-002, and swivel core, slider (swivel rod, core) ln 465207, pn000331 were used in the manufacture of ln 464990.Both lots met incoming inspection requirements and were accepted by atrium for use (ir465494 and ir465207).The measurements of the swivel rod, cores and swivel rod, sliders for critical dimensions from the two units associated with the customer complaints and two units from different lots on crimped on the same shift as the affected lot.All dimensions measured were within specification (attachment 16).Machine evaluation: crimping vise, eq# 6014, was used to secure the gds swivel rods to the cores per (b)(4) (rev az).Per rm000131 ¿ manual for eq# 6014: slider crimping vise (rev 00), eq# 6014 is an air operated ferrule vise crimper.It is connected to house air that is regulated to a foot pedal valve.Four dies are within a vise that is covered by a faceplate secured with two wingnuts.The wingnuts have two projections which allows them to be loosened and tightened by hand without any tools.Tl000523 ¿ assy,slider crimping vise (rev aa).The dies close around the ferrule (swivel rod, slider) to crimp it to the (swivel rod, core) when the vise is activated.The swivel rod, slider, is able to spin around the core.Incoming house compressed air is regulated to 80 psi on the unit via a pressure regulator per mp000753 (rev az).Rm000131 (rev 00) indicates that periodic inspection, cleaning and lubrication of all moving parts is necessary for proper operation of the vise.Building management system (bms) report for house compressed air was evaluated to determine if pressure was below specification.Report shows house compressed air remained above 90 psi on 28oct2020 from 12:01 am to 11:59 pm (date ln 440990 was crimped) and that there were no pressure excursions per rf009285 ¿ tracer system points of monitoring and alarm merrimack facility (rev ag).Maintenance records were evaluated in blue mountain regulatory asset management (bmram) system.There were no unplanned (on demand) maintenance events on this unit in from 28jun2018 to 27may2021.The last preventive maintenance (pm) event occurring before the crimping of the affected lot was on 29jun2020 (bmram # m-023888) per rm000128 ¿ master pm, eq# 6014: slider crimping vise (rev 01).Pm activities included actuating the crimper and ensuring smooth movement through the entire range of motion, inspecting the crimping jaws for damage, ensuring that the inner diameter of the closed vise does not exceed 0.105 inches.Record shows that maximum gage pin size that would fit into the vise was 0.101 inches.Maintenance activities require that the faceplate is removed to access the jaws.On 25jun2021, after the crimping occurred for the affected lot, an annual pm was performed on eq# 6014 (m-034799).Inner diameter of the crimping vise jaws was measured at 0.104 inches using gage pin set, eq# 10762 (calibration due date 28feb2022).The jaws were initially found to be worn and were replaced under ncr004668.Evaluation through the ncr004668 determined that initial jaws were acceptable and re-installed them on the crimping vise.There is no impact to product due to the wear observed because inner diameter of the closed crimping vise jaws was less than 0.105 inches which aligns with the requirement in rm000128 (rev 02).Gage pin set, eq# 10762, was used for pm event (m-023888) and was within calibration expiry of 31jan2021.Maintenance records were evaluated in bmram for pin set, eq# 10762.There were no maintenance events since 21jan2019.Calibration that occurred after this event, on 29jan2021, indicated that the 0.101 inch pin was in tolerance (c-030163).Gauge, pressure, 0-160 psi, eq# 6399, was used to regulate the air per mp000753 (rev az).Maintenance records in bmram show there were no on demand maintenance events for the unit since 31jul2019.The unit was within calibration expiry (calibration due date 31aug2021) at the time of use in ln 464990 (c-025837).Assessment of other lots built on the same shift inventory of gds graft lots built on the same shift by the same two operators who performed the gds assembly of pn 25126, ln 464990 at approximately 12:23 am on 28oct2020 were assessed.The following three units were the only units in inventory and were returned for investigational purposes.Two units of pn 22019, ln 464970 (sn (b)(6)), built before the affected lot on 27oct2020 at approximately 9:30 pm.One unit of pn 22175, ln 464919 (sn (b)(6)), built immediately after the affected lot on 28oct2020 at approximately 12:52 am.On 07jul2021, these three units were tested per test procedure tp000408 (rev aj) to identify if the units met the minimum 8 lbf requirement for gds separation or pull out.The three samples exhibited failure modes of ¿crimp failure¿ with peak loads above 8 lbf; all exceeded the minimum requirement with an average of 18.09 lbf.Since there are not set-up actions for the slider crimping vise between lots other than ensuring the pressure is set to at least 80 psi, it is reasonable to expect that these lots were crimped under similar conditions as the affected lot.Manufacturing engineer evaluation: as part of this investigation, me evaluated the crimping process by creating sample gds assemblies.Upon me¿s initial evaluation the faceplate on the crimping vise was found to be securely attached to the machine.Me observed that when the pressure was adjusted on crimping vise, eq# 6014, above or below 80 psi the vise still fully actuated and created a properly crimped assembly.Me observed that when foot pedal was quickly pushed the vise still fully actuated.Me found that when the pressure was set to nominal (80 psi) and the two wingnuts on crimping vise, eq# 6014, faceplate were loosened approximately ½ of a turn, the gds assemblies showed the characteristic four crimp marks from the four jaws.It was observed that in this situation the swivel rod, slider could be pushed/pulled from the swivel rod, core by hand.When the 500g weight was hung from the units, the gds did not separate.Based on the evaluation of the returned product and review of the manufacturing process and equipment the root cause could not be determined, therefore the reported complaint cannot be confirmed.
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