| Seq | Brand | Generic | Manufacturer | Product code | Model | Catalog | Lot | PMA | 510(k) | Implant | Evaluated | Availability |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | LEKSELL GAMMA KNIFE PERFEXION | SYSTEM, RADIATION THERAPY, RADIONUCLIDE | ELEKTA INSTRUMENT AB | IWB | Y | Y |
| Sequence | Received | Treatment | Outcome |
|---|---|---|---|
| 1 | 2015-03-20 | 0 | 1. O |
Patient 1
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 1
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 1
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.