LEKSELL GAMMA KNIFE PERFEXION

Additional Manufacturer Narrative

THE INVESTIGATION WAS COMPLETED BY CONDUCTING A THOROUGH EVALUATION OF THE PRODUCT AND THE REPORTED INFORMATION. THE EMERGENCY STOP FUNCTION IS DESIGNED IN ORDER TO STOP MOTION OF THE PPS (PATIENT POSITIONING SYSTEM) AND THE SHIELDING DOORS IN CASE COLLISION OCCURS WITH THE COLLIMATOR CAP OR WHEN THE OPERATOR ACTIVATES THE EMERGENCY STOP BUTTON ON THE OPC (OPERATOR ROOM PANEL) OR THE EXTERNAL EMERGENCY STOP BUTTON PRESENT IN THE TREATMENT ROOM (OPTIONAL). THE DESIGN IS BASED UPON THE LEKSELL GAMMA KNIFE SAFETY SYSTEM WHICH IS A PURE HARDWARE (HW) ELECTRONICS SYSTEM DESIGNED TO ENSURE THAT A SEQUENCE OF ACTIONS IS PERFORMED WHEN IT DETECTS THAT EMERGENCY STOP HAS BEEN TRIGGERED. THE INITIAL FAILURE MODE OF A HAZARDOUS SITUATION (HEAD COLLISION) IS A SOFTWARE (SW) ERROR IN THE SERVO SOFTWARE MAKING IT CONTINUE MOVEMENT ALTHOUGH THE ENABLE INPUT IS DE-ACTIVATED. SOFTWARE ERRORS NEEDS TO BE MITIGATED SO THAT A DOUBLE FAULT IS NEEDED FOR THE EFFECT TO OCCUR. THERE ARE 2 MITIGATION'S IN PLACE: THE SERVO RELAYS AND THE EMERGENCY STOP RELAY. HOWEVER, THESE RELAYS COULD BREAK WITHOUT BEING DETECTED. THE TESTS PERFORMED ON THE RELAY INDICATES THAT TOO HIGH IN-RUSH CURRENT COULD BREAK THE RELAY, HOWEVER NO BROKEN RELAYS HAVE BEEN NOTICED DURING UPGRADE FROM LGK PERFEXION TO ICON OR LGK PERFEXION SW UPGRADE FROM 10.X TO 11.X SW VERSION. APPROXIMATELY 107 SITES HAVE UNDERGONE THESE UPGRADES. THE OBSERVATIONS FROM PERFORMED UPGRADES INDICATE THAT THE EMERGENCY STOP RELAYS ARE NOT BREAKING DUE TO THE ACTUAL IN-RUSH CURRENT. FURTHERMORE THERE ARE SERVO RELAYS AS AN ADDITIONAL MITIGATION OF THE INITIAL SW ERROR IN THE SERVO. THE FOLLOWING HAS BEEN UPDATED: EMAIL ADDRESS ADDED. CONTACT OFFICE: ESTABLISHMENT NAME AND ADDRESS UPDATED. RESUBMITTING FORM 3500A. IT WAS REQUESTED BY FDA MEDWATCH PROGRAM DEPARTMENT TO RE-SUBMIT THE INITIAL REPORT AND FOLLOW-UP 1 REPORT FOR 9612186-2020-00000 AS THESE TWO REPORTS HAVE BEEN REJECTED DUE TO INVALID SEQUENCE NUMBER (00000) IN EMDR SYSTEM. THE MFR REPORT NUMBER IS CORRECTED IN THIS RE-SUBMISSION. CORRECTION TICKED.

Description of Event or Problem

DURING INTERNAL TESTING AT ELEKTA IT WAS OBSERVED THAT THE EMERGENCY STOP RELAY FUNCTIONALITY IS NOT MONITORED BY THE CONTROL SYSTEM (CS) SOFTWARE (SW), LEADING TO THE RISK OF A SLEEPING FAULT ON THE EMERGENCY STOP RELAY.

Additional Manufacturer Narrative

THE INVESTIGATION CONCLUDED THAT THERE ARE NO CORRECTIVE ACTIONS NEEDED FOR THIS ISSUE AND THAT THE CURRENT MITIGATIONS SHOULD BE SUFFICIENT. H10 THE FOLLOWING HAS BEEN UPDATED: SECTION G7: RESUBMITTING FORM 3500A. IT WAS REQUESTED BY FDA MEDWATCH PROGRAM DEPARTMENT TO RE-SUBMIT THE INITIAL REPORT AND FOLLOW-UP 1 REPORT FOR 9612186-2020-00000 AS THESE TWO REPORTS HAVE BEEN REJECTED DUE TO INVALID SEQUENCE NUMBER (00000) IN EMDR SYSTEM. THE MFR REPORT NUMBER IS CORRECTED IN THIS RE-SUBMISSION AS 9612186-2020-00009. SECTION H2: CORRECTION TICKED.