Model Number ROB10024 |
Device Problem
Application Program Problem: Parameter Calculation Error (1449)
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Patient Problems
Injury (2348); Deformity/ Disfigurement (2360)
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Event Date 09/10/2020 |
Event Type
Injury
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Event Description
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It was reported that, during a cori procedure, they used both the side and the end of the bur in speed control to refine the surface of the bone.There was a discrepancy visible on the order of 1 to 2 mm between the bone surface refined with the side of the bur relative to the registered position of the tip of the bur.(when he placed the tip of the bur on the bone surface where he'd just refined, the tip hovered over the refined surface by 1-2mm.The pointer probe was used to check the surface, and the pointer probe tip agreed with the handpiece tip location.The doctor used a saw to cut most of the medial side of the joint, and did not seem to finish the lateral side.The plate probe was used to verify the cut, which registered a 2 degree varus cut relative to plan, which would be consistent with the final coloring of the surface.This also tends to agree with the final registered leg alignment, which was 6 degrees, as opposed to a planned 3 degrees of varus.The doctor stated that the 6 degree reported alignment "looks like 3 degrees").It was difficult to know how much of the "red" on the medial condyle was a contributor to the varus cut error, or if it was simply a "virtual overcut".The robotic drill/handpiece, tacker and long attachment used in this case could also be bent or loose, which could have contributed to the event.The troubleshooting of the shaving discrepancy added 5 to 10 minutes of delay.No other complications were reported.
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Manufacturer Narrative
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H3, h6: the real intelligence cori, pn: rob10024, sn: (b)(6) used for treatment was not returned to the designated complaint unit for evaluation, therefore a visual and functional inspection could not be performed.The reported problem could not be visually or functionally confirmed.There were no screenshots of the bone in refine cutting mode to confirm a 1 to 2 mm difference of the physical and virtual bur tip location; nor did they show that the checkpoints were voluntarily verified during the bone removal stage to identify tracker movement.The bone model refinement stage, as described in the cori user's manual, depicts a model generated from the selected implant block model and the bone mesh.The bur tip or the guard of the robotic drill (in exposure mode) can be used to update the virtual bone model, to depict the current state of the bone surface.The case was put in case visualizer, where it was verified that the checkpoints were in the bone, and in positions that would not have been disturbed during bone removal.This indicates that tracker movement was unlikely.Per the cori user's manual, checkpoints are referenced to determine if either tracker has moved.If there is concern that a tracker has moved, confirm that the trackers are in the position recorded previously by verifying checkpoints.Screenshots confirmed the live read-out of a 1.8 degree varus cut relative to the planned 2 degree varus cut of the tibia using the plane visualizer tool.The case information screen shows that the planned alignment was 3 degrees varus, and the achieved alignment shows 7 degrees varus.It also shows that both the femur and tibia were each planned with 2 degrees of varus.This indicates there was a total of 3 degrees of unplanned varus overcut.A review of manufacturing records indicate the software met all specifications upon release into distribution.A complaint history review found similar reports, this issue will continue to be monitored.No further medical assessment could be rendered at this time.Should clinically relevant documentation/information become available, the clinical/medical task may be re-evaluated.Due to the additional 1.8 degree varus cut of the tibia relative to the plan, the 2 degrees of planned varus for the tibia, and 2 degrees of planned varus for the femur, it is likely that the over-resected (red) bone on the medial condyle contributed to the varus overcut, and was not just a ¿virtual¿ overcut.Therefore the reported complaint was not confirmed.A potential cause of the medial overcut could be due to the use of manual instrumentation (saw) when cutting most of the medial side of the joint, and not burring the remaining bone to the target surface of the lateral side of the tibia.As found in the cori user's manual, white indicates that the target surface has been reached during the bone removal stage.Bone to be removed changes colors based on its thickness.As bone is removed, the onscreen model indicates the depth of the cut.The goal is to cut through the colored layers of bone until the white target surface is revealed.This situation is captured in the optimus risk assessment released at the time of the complaint.As a result of these findings, it was determined that the system functioned as intended; no defect of the system occurred.Based on the investigation, no containment or corrective actions are recommended at this time.
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Manufacturer Narrative
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H3, h6: the real intelligence cori, pn: rob10024, sn: (b)(6) used for treatment was returned to the designated complaint unit for evaluation.A visual inspection and functional evaluation were done on the console.There were no visual or functional non-conformances related to the reported event identified.The software files were downloaded from the device and provided for investigation.Screenshots confirmed the live read-out of a 1.8 degree varus cut relative to the planned 2 degree varus cut of the tibia using the plane visualizer tool.The final tibia bone removal screen shows some blue and green bone that had not been burred away along the periphery of the lateral plateau.This, in addition to possible over-resection of the medial side using manual instrumentation likely contributed to the varus cut error.The case information screen shows that the planned alignment was 3 degrees varus, and the achieved alignment 7 degrees varus.It should be noted that the achieved alignment is an estimate and is completely dependent on how the user holds the leg.Therefore, with an achieved alignment of 7 degrees, 3 degrees of varus was unplanned because the femur and tibia were each planned with 2 degrees of varus (total of 4 degrees varus).The 1.8 degrees of additional varus as reported in the visualize cut screen in addition to the 4 degrees of planned varus is around 6 degrees, which is close to the 7 degrees varus achieved alignment.The most likely cause of the over-resected (red) bone on the medial plateau and under-resection of the lateral plateau is the manual overcut.The 1-2 mm distance between the bur tip/point probe and the refined bone surface could not be confirmed in screenshots.Checkpoints were not voluntarily verified during bone removal, however checkpoint verification was taken after bone cutting was completed with no errors.Therefore, tracker movement is unlikely so long as the checkpoints were not taken on the clamps or the bone trackers.The drill and tracker used in this case were returned for evaluation and functioned as intended.The point probe, however, was not returned.No further assessment can be made on the hovering of the of both the point probe and the bur tip during this case.As a result of these findings, it was determined that the system functioned as intended; no defect of the system occurred.The clinical/medical evaluation concluded: ¿based on the information provided the impact beyond the reported ¿varus cut error¿ and a 5-10 minute surgical delay could not be definitively determined; although, it was communicated that there was no additional interventions required and surgeon was ultimately satisfied with the surgical outcome.No further medical assessment could be rendered at this time.Should clinically relevant documentation/information become available, the clinical/medical task may be re-evaluated.¿ in reference to the blue and green bone that remained to be burred: as found in the cori user's manual, white indicates that the target surface has been reached during the bone removal stage.Bone to be removed changes colors based on its thickness.As bone is removed, the onscreen model indicates the depth of the cut.The goal is to cut through the colored layers of bone until the white target surface is revealed.This situation is captured in the risk assessment released at the time of the complaint.The failure mode and associated risk have been anticipated within the risk file and that the documented risk level is still adequate.A review of manufacturing records indicate the software met all specifications upon release into distribution.A complaint history review found similar reports.A review of prior escalation actions was performed and found no actions that are applicable to the scope of the reported complaint.This issue will be continuously monitored through complaint investigation and post market surveillance.Based on the investigation, no containment or corrective actions are recommended at this time.
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Search Alerts/Recalls
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