MAUDE data represents reports of adverse events involving medical devices. This maude entry was filed from a 00,05,06 report with the FDA on 2015-03-20 for LEKSELL GAMMA KNIFE PERFEXION manufactured by Elekta Instrument Ab.
[21724634]
The customer reported that the lgk perfexion was not passing the clearance test tool test on the z movements. When the installation diode tool was used to validate the focus precision, a discrepancy in z was found of 1. 87 mm. Eight patients were affected as a result of this error, however, the clinical impact is currently unknown and is being investigated by the hospital.
Patient Sequence No: 1, Text Type: D, B5
[22284121]
Due to human error, the lgk unit was incorrectly calibrated, resulting in the disablement of the mechanical stop check and the qa focus precision check. As a result, the lgk unit performed 8 patient treatments with a pps z-positioning error of 1. 87 mm, before being detected by hospital staff and the lgk unit taken out of clinical use. The initial root cause analysis was performed by the manufacturer using the system log data, and concluded that the following 3 actions resulted in the error:- 1. The pps. Ini file was exchanged to an older version resulting in a faulty calibration of the pps z-axis. 2. The mechanical stop was miscalibrated although not damaged, which prevented the system to detect the wrong patient position 3. The qa tool was re-calibrated and the result showed a approx. 2 mm (rounded up) offset on z-axis. Due to human error, this warning was ignored and the system was allowed to be used for treatment. The above actions all required human interaction with the system and were not performed by the system software itself. The reported shift was not an effect of a mechanical failure or bug in the control system software. The device has been adjusted and returned to clinical use. The manufacturer's investigation is ongoing to determine the clinical impact of mistreatment and the corrective and preventative actions.
Patient Sequence No: 1, Text Type: N, H10
[35373440]
Manufacturer's investigation (final report): a root cause analysis was performed by the manufacturer using the system log data, and concluded that the following 3 actions resulted in the error:- 1. The pps. Ini file was exchanged to an older version resulting in a faulty calibration of the pps z-axis. 2. The mechanical stop was calibrated although not damaged, making the mechanical stop verification was unable to detect the problem. 3. The qa tool was re-calibrated and the result showed a approx. 2 mm (rounded up) offset on z-axis. Due to human error, this warning was ignored and the system was allowed to be used for treatment. The above actions all required human interaction with the system and were not performed by the system software itself. The reported shift was not an effect of a mechanical failure or bug in the control system software. Risk mitigations implemented in the system software were concluded to be sufficient. Since changes to the system can be made by human service engineers, service actions in general are susceptible to human error. These are mitigated by both system checks of the calibration data and instructions to verify the system using specific tools both by engineers and the clinical user. For human error to cause an incorrectly calibrated system multiple actions must be performed in error. The error must first be committed, then the system's own checks and warnings must be manually approved/ overridden/recalibrated then the procedural verification of the service actions must be ignored. Only then will the system become available for clinical use with an incorrect calibration. It was not possible to make a general clinical evaluation since the clinical effects are much depended on diagnosis and location. In order to understand any potential clinical effects and make a complete clinical evaluation elekta needs to know target locations, volume, type of target (tumor type, functional, avm, etc) dose delivered, etc. Due to patient privacy reasons, the hospital was not willing to provide this information to elekta at the time of this report.
Patient Sequence No: 1, Text Type: N, H10
| Report Number | 9612186-2015-00003 |
| MDR Report Key | 4619273 |
| Report Source | 00,05,06 |
| Date Received | 2015-03-20 |
| Date of Report | 2015-06-18 |
| Date Mfgr Received | 2015-02-19 |
| Date Added to Maude | 2015-03-20 |
| Event Key | 0 |
| Report Source Code | Manufacturer report |
| Manufacturer Link | Y |
| Number of Patients in Event | 0 |
| Adverse Event Flag | 3 |
| Product Problem Flag | 3 |
| Reprocessed and Reused Flag | 3 |
| Health Professional | 3 |
| Initial Report to FDA | 3 |
| Report to FDA | 0 |
| Event Location | 0 |
| Manufacturer Contact | GPMS |
| Manufacturer Street | LINAC HOUSE FLEMING WAY |
| Manufacturer City | CRAWLEY, WEST SUSSEX RH109RR |
| Manufacturer Country | UK |
| Manufacturer Postal | RH10 9RR |
| Manufacturer G1 | ELEKTA INSTRUMENT AB |
| Manufacturer Street | PO BOX 7593 FLEMING WAY |
| Manufacturer City | STOCKHOLM, SE103 93 |
| Manufacturer Country | SW |
| Manufacturer Postal Code | SE103 93 |
| Single Use | 3 |
| Remedial Action | MA |
| Previous Use Code | 3 |
| Event Type | 3 |
| Type of Report | 3 |
| Brand Name | LEKSELL GAMMA KNIFE PERFEXION |
| Generic Name | SYSTEM, RADIATION THERAPY, RADIONUCLIDE |
| Product Code | IWB |
| Date Received | 2015-03-20 |
| Operator | HEALTH PROFESSIONAL |
| Device Availability | Y |
| Device Age | DA |
| Device Eval'ed by Mfgr | Y |
| Device Sequence No | 1 |
| Device Event Key | 0 |
| Manufacturer | ELEKTA INSTRUMENT AB |
| Manufacturer Address | PO BOX 7593 STOCKHOLM, SE103 93 SW SE103 93 |
| Patient Number | Treatment | Outcome | Date |
|---|---|---|---|
| 1 | 0 | 1. Other | 2015-03-20 |