MAUDE Adverse Event Report: ELEKTA LTD PRECISE SERIES LINAC; ACCELERATOR, LINEAR, MEDICAL

Model Number 152190

Device Problem Device Displays Incorrect Message (2591)

Patient Problem No Known Impact Or Consequence To Patient (2692)

Event Date 12/04/2014

Event Type  malfunction  

Event Description

The customer reported the following: 'during qa physics found the long table position was not consistent and could be up to 4mm of error when the system asu was used to reposition the qa phantom.'.

Manufacturer Narrative

The manufacturers preliminary investigation has established the following sequence of events occurred at this customer's site: on (b)(6) 2014: intermittent errors due to longitudinal table movement; to resolve this issue the check potentiometer was replaced.All three potentiometers (check, fine and coarse) were removed during this replacement; this is not the normal method of replacing the check potentiometer; post replacement the positioning of the table was checked and confirmed all was okay.On (b)(6) 2014: physics qa was carried out and all movements and positions confirmed as okay.On (b)(6) 2014: hospital noticed a positional error of 4mm; fine potentiometer was replaced.Based off the series of events that occurred at the customer site, the likely cause of this error is that the fine potentiometer was incorrectly refitted or damaged when all 3 potentiometers were removed in the original service.If the fine potentiometer was incorrectly refitted or damaged this would cause an abnormal load to the potentiometer shaft - the outcome of this could be a 4mm error.The replacement of the fine potentiometer would subsequently fix the 4mm position issue, and the stiff longitudinal movement.The initial corrective action consisted of replacing the fine potentiometer.The device was then tested and returned to clinical use.

Manufacturer Narrative

Manufacturer's device analysis results: the manufacturers final investigation has concluded that the likely causes of this error are as follows: seized potentiometer bearing may have caused bracket to bend or vice versa - damaged bracket caused pot to have side load causing the potentiometer bearing to collapse.This would cause the intermittent 4mm error due to mismatch in pot position.Potentiometer was loose on its fixing to the mounting bracket.Potentiometer gear was loose as grub screw was not tight.Daily qa will find this, including backlash check for which a notice has already been released to customer explaining.Remedial action/corrective action/preventive action / field safety corrective action: potentiometer assembly has been replaced and fitted.The manufacturer will be carrying out a mandatory field safety corrective action for another issue relating to potentiometer assembly, this will involve a mandatory training course for all service engineers to reinforce the correct fixation method and the potential consequences of not correctly fitting these assemblies.Time schedule for the implementation of the identified actions: the training video is anticipated for release at the end of april 2015.Additional information risk assessment: likelihood: there is no risk to clinical users or service users as mispositioning of precise table only presents a risk to clinical mistreatment.The likelihood of this failure is deemed to be improbable based on the fact it requires either a mechanical failure or an installation error, along with the fact there is a potential for the user to detect the issue through daily qa.Risk: for normal treatments the severity of this issue is judges to be moderate, with a likelihood of improbable.For this scenario the risk is judged to be acceptable if it is a system used for srs the severity would be increased to major, however the likelihood would still be improbable.For this scenario the risk is judged to be tolerable.Further information requested by the fda: please provide further explanation regarding how you determined the conclusion(s) code(s) reported in your medical device report.The investigation concluded that the reported event was likely to have been caused by component failure and/or installation error.Total number of devices manufactured, distributed and, if available, used over the last 3 years (by year) for the device indicated in the medical device report.Please indicate the proportions distributed in the us and outside the us.(b)(4).Please provide a complete list of all medical device reporting (mdr) access numbers, as well as the reason for their inclusion in the trend.(b)(4).The reason this was included in the trend is because this case also related to a mispositioning of the precise table caused by failure of the potentiometer assembly.Please identify the software version(s) involved in this event.Additionally, please describe any software modifications since the device received fda premarket approval or clearance.Not applicable; this was not a software issue.

• Brand Name: PRECISE SERIES LINAC
• Type of Device: ACCELERATOR, LINEAR, MEDICAL
• Manufacturer (Section D): ELEKTA LTD; linac house; fleming way; crawley, west sussex RH10 9RR; UK RH10 9RR
• Manufacturer (Section G): ELEKTA LTD; linac house; fleming way; crawley, west sussex RH10 9RR; UK RH10 9RR
• Manufacturer Contact: gpms ; linac house; fleming way; crawley, west sussex RH10 -9RR ; UK RH10 9RR
• MDR Report Key: 4355852
• MDR Text Key: 21552190
• Report Number: 9617016-2014-00015
• Device Sequence Number: 1
• Product Code: IYE
• Combination Product (y/n): N
• Reporter Country Code: SZ
• PMA/PMN Number: K963624
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Other,Health Professional,User Facility
• Reporter Occupation: Health Professional
• Remedial Action: Repair
• Type of Report: Initial,Followup
• Report Date: 03/23/2015

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: 152190
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Initial Date Manufacturer Received: 12/04/2014
• Initial Date FDA Received: 12/23/2014
• Supplement Dates Manufacturer Received: Not provided
• Supplement Dates FDA Received: 03/24/2015
• Was Device Evaluated by Manufacturer?: Yes
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Patient Sequence Number: 1