Model Number ROB10024 |
Device Problem
Application Program Problem: Parameter Calculation Error (1449)
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Patient Problem
Unspecified Tissue Injury (4559)
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Event Date 05/24/2021 |
Event Type
Injury
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Event Description
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It was reported that during a cori assisted tka surgery, the real intelligence cori showed that the bur extended 1 cm beyond the bony surface margin into negative posterior space between the condyles.The case was still completed with cori.The procedure was completed, without delay using the same device.No patient injuries and no other complications were reported.
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Event Description
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It was reported that during a cori assisted tka surgery, the real intelligence cori showed that the bur extended 1 cm beyond the bony surface margin into negative posterior space between the condyles.A minor amount of additional bone was removed, however, not to the patient's detriment.The case was still completed without any delay with cori.
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Manufacturer Narrative
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Internal complaint reference number: (b)(4).
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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, visual and functional inspections could not be performed.The case files and videos of the case were provided and the reported problem was confirmed.The distal cut of the femur bone removal screen shows some slightly over-resected bone along the inner edges of both condyles, and at the very bottom of the lateral condyle.The videos provided show the bur extending in the negative posterior space between the condyles, but the 1 cm extension could not be confirmed.The videos and screenshots were further reviewed with software engineering.Where the bur appears to be between the two condyles, the video was paused and zoomed in on the cori monitor.The screen shows the guard over some of the bone in between the condyles.Where the guard had been projected, the bur could see spare bone.The bur then exposed itself to reach the spare bone.A quick, sideways movement of the drill could cause the bur to extend into the negative posterior space between the condyles, and also shave off a voxel of the bone as seen in the femur cut screen.The yellow drill symbol was displayed at times during cutting.This indicates the user had moved the drill quicker than the recommended velocity.The "projective aggressive" algorithm is used to determine the allowed bur exposure at the given guard/bur distances to the spare bone.The guard is projected onto the bone, and from that position, it determines how much the bur can extend to the closest 'spare' bone (spare bone is not to be cut).Regardless if there is intended ('waste') bone to be cut in order to reach the spare bone, the bur will extend to reach, but not resect, the spare bone if it is within the bur's "sight" and maximum exposure range of 12 mm.Over-resection is possible when the bur is exposed and the drill moves quicker than the expected retraction time (45 milliseconds at full exposure) over spare bone that is now closer to the guard.This is most noticeable when the guard is at an angle with, and not perpendicular to, the bone.The guard is more likely to create these angles when moved back and forth near the edges of the bone.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.The clinical/medical evaluation concluded that the root cause could not be definitively concluded, however user technique as a contributing factor to the additional bone removal could not be ruled out.The 1 cm bur extension could not be confirmed, although the video confirmed bur extension.The assessed patient impact was the ¿minor¿ additional bone removal.Reportedly, the case was completed without delay with same cori device.No further assessment is warranted at this time.The most likely cause of the reported event is the expected behavior of the system where the bur exposed itself to the spare bone at an angle, and the retraction time was not quick enough to prevent an overcut.It was determined that the software functioned as intended; no defect of the system occurred.According to the cori user's manual, utilize exposure control mode with the bur working perpendicular to the cutting surface is recommended for easily accessible areas that are unrestricted by boney anatomy.Trace around the outer edge of the implant cut plan.Make left-right or up-down passes to remove the remaining middle bone.The user should avoid quick passes of the tool over the surface.To remove bulk bone, a slow, methodic ¿plunge and drag motion¿ through to the cortical layer, will remove bone with the greatest efficiency.The bur remains protruded only until it has reached the target surface, and the bur exposure actively adjusts so that cutting beyond the target surface is minimized.When removing bone, the yellow drill symbol will display when the drill movement exceeds the recommended velocity, which may lead to overcutting.This situation is captured in the optimus risk assessment released at the time of the complaint.Further analysis of the software related to this event is being conducted by the software engineering team.No further containment or correction is required at this time.
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Manufacturer Narrative
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The real intelligence cori, pn: rob10024, sn: (b)(6) used for treatment was not returned to the designated complaint unit for evaluation, therefore, visual and functional inspections could not be performed.The case files and videos of the case were provided and the reported problem was confirmed.The distal cut of the femur bone removal screen shows some slightly over-resected bone along the inner edges of both condyles, and at the very bottom of the lateral condyle.The videos provided show the bur extending in the negative posterior space between the condyles, but the 1 cm extension could not be confirmed.Further screenshot review found a large red area in the posterior space between the condyles, however the drill was in manual mode.Cori will not stop bur rotation or retract the bur while in manual mode (control modes are off).The videos and screenshots were further reviewed with software engineering.The videos are of the user in exposure mode, not manual mode.Where the bur appears to be between the two condyles, the video was paused and zoomed in on the cori monitor.The screen shows the guard over some of the bone in between the condyles.Where the guard had been projected, the bur could see spare bone.The bur then exposed itself to reach the spare bone.A quick, sideways movement of the drill could cause the bur to extend into the negative posterior space between the condyles, and also shave off a voxel of the bone as seen in the femur cut screen.The yellow drill symbol was displayed at times during cutting.This indicates the user had moved the drill quicker than the recommended velocity.The "projective aggressive" algorithm is used to determine the allowed bur exposure at the given guard/bur distances to the spare bone.The guard is projected onto the bone, and from that position, it determines how much the bur can extend to the closest 'spare' bone (spare bone is not to be cut).Regardless if there is intended ('waste') bone to be cut in order to reach the spare bone, the bur will extend to reach, but not resect, the spare bone if it is within the bur's "sight" and maximum exposure range of 12 mm.Over-resection is possible when the bur is exposed and the drill moves quicker than the expected retraction time (45 milliseconds at full exposure) over spare bone that is now closer to the guard.This is most noticeable when the guard is at an angle with, and not perpendicular to, the bone.The guard is more likely to create these angles when moved back and forth near the edges of the bone.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.The clinical/medical evaluation concluded that the root cause could not be definitively concluded, however user technique as a contributing factor to the additional bone removal could not be ruled out.The 1 cm bur extension could not be confirmed, although the video confirmed bur extension.The assessed patient impact was the ¿minor¿ additional bone removal.Reportedly, the case was completed without delay with same cori device.No further assessment is warranted at this time.The most likely cause of the reported event is the expected behavior of the system where the bur exposed itself to the spare bone at an angle, and the retraction time was not quick enough to prevent an overcut.It was determined that the software functioned as intended; no defect of the system occurred.According to the cori user's manual, utilize exposure control mode with the bur working perpendicular to the cutting surface is recommended for easily accessible areas that are unrestricted by bony anatomy.Trace around the outer edge of the implant cut plan.Make left-right or up-down passes to remove the remaining middle bone.The user should avoid quick passes of the tool over the surface.To remove bulk bone, a slow, methodic ¿plunge and drag motion¿ through to the cortical layer, will remove bone with the greatest efficiency.The bur remains protruded only until it has reached the target surface, and the bur exposure actively adjusts so that cutting beyond the target surface is minimized.When removing bone, the yellow drill symbol will display when the drill movement exceeds the recommended velocity, which may lead to overcutting.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.Further analysis of the software related to this event is being conducted by the software engineering team.No further containment or correction is required at this time.
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Search Alerts/Recalls
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