N’Vision® and InterStim iCon® used with InterStim implantable neurostimulator model 3023 for pelvic floor disorders neurostimulator programmers - error in programmer software

(Medtronic) error in the programmer software (revision NNB_01) which may lead to false warnings of a low battery status. (MDA/2008/065)

Action deadlines for the central alerting system (CAS)

Action underway: 10 October 2008, action complete: 11 December 2008

Device

Medtronic N’Vision® clinician programmer (fitted with the InterStim B software – 8870 NNB_01 application card) and InterStim iCon® patient programmer (model 3037) when used with InterStim implantable neurostimulator (model 3023) for pelvic floor disorders.

Problem

An error in the programmer software (revision NNB_01) may lead to false warnings of a low battery status. There is a risk that pre-existing symptoms may return if the device ceases to function when true low or end of service battery warnings are subsequently ignored.

There are three ways to measure battery status in the model 3023 InterStim neurostimulator:

  1. using the InterStim iCon patient programmer
  2. Automated Measurement feature on N’Vision clinician programmer
  3. Therapy Measurement feature on N’Vision clinician programmer.

Medtronic has identified that only the Therapy Measurement feature on the N’Vision programmer is accurate. It is therefore important to interpret all other low battery warnings with caution.

In July 2007 Medtronic issued a Field Safety Notice (FSN) to alert users to the potential for false low battery warnings on the clinician and patient programmers and to advise of an accurate way to assess the battery capacity on the clinician programmer (see Appendix). Clinicians were advised that patients experiencing a low battery warning on their programmer (which were subsequently confirmed as false in clinic) should ignore further low battery warnings. The FSN also advised that new software was in development for both clinician and patient programmers to address the issue.

In July 2008 Medtronic advised the MHRA that the software upgrade was in the approval process and would not be available for implementation for a further few months.

It is possible that some model 3023 InterStim devices are now nearing the end of their life, and so genuine low battery alerts may be ignored (although it should be noted that the end of service (EOS) battery alert on the iCon programmer is valid). This could lead to a device ceasing to function before it can be replaced, and a return of the patient’s pre-existing symptoms.

Action

You should:

  • consider the need for in clinic review of battery status for patients who have received multiple low battery alerts on their iCon programmer or if their neurostimulator has been implanted for more than two years
  • confirm battery status using the N’Vision Therapy Measurement feature, which is a reliable indicator - do not rely on the N’Vision low battery alert in the Automated Measurement feature to assess battery status

Action by

All healthcare professionals who are involved in the management of patients with this device

Distributed to:

  • NHS trusts in England - chief executives
  • Healthcare Commission (CHAI) - headquarters
  • NHS Boards in Scotland - chief executives

Distribution

Bring this notice to the attention of all who need to know or be aware of it. This may include distribution by trusts to:

  • CAS liaison officers for onward distribution to all relevant staff including
  • clinical governance leads
  • gynaecology departments
  • gynaecology lead nurses
  • gynaecology surgical directors
  • medical directors
  • medical physics departments
  • nursing executive directors
  • risk managers
  • urological surgery, directors of
  • urology departments
  • urology lead nurses

Healthcare Commission (CHAI) to headquarters for onward distribution to:

  • hospitals in the independent sector
  • independent treatment centres

Manufacturer contact

Dr David Dunham
Regulatory Affairs Manager – UK & IrelandMedtronic Limited
Suite One Sherbourne House
Croxley Business Centre
Watford
Herts
WD18 8WW

Tel: 01923 212 213 Fax: 01923 241 004 E-mail: david.dunham@medtronic.com

England

Enquiries to the MHRA should quote reference number 2007/002/001/401/009 and be addressed to:

Technical aspects
Miss Katy Hopkins or Ms Hazel Randall
Medicines & Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane
London
SW8 5NQ

Tel: 020 7084 3176 / 3287 Fax: 020 7084 3106 E-mail: katy.hopkins@mhra.gsi.gov.uk

Clinical aspects
Dr Christopher Brittain Medicines & Healthcare products Regulatory Agency
Market Towers
1 Nine Elms Lane
London
SW8 5NQ

Tel: 020 7084 3126 Fax: 020 7084 3103 E-mail: christopher.brittain@mhra.gsi.gov.uk

Scotland

Enquiries for Scotland should be directed to:

Incident Reporting and Investigation Centre Health Facilities
Scotland NHS National Services
Scotland Gyle
Square1
South Gyle Crescent
Edinburgh
EH12 9EB

Tel: 0131 275 7575 Fax: 0131 314 0722 E-mail: [iric@shs.csa.scot.nhs.uk](mailto:iric@shs.csa.scot.nhs.uk)

Change of address or removal from address list for Healthcare Commission:

Healthcare Commission Finsbury Tower 103-105 Bunhill Row London EC1Y 8TG $A

Tel: 020 7448 0842 E-mail: contacts@healthcarecommission.org.uk

How to report adverse incidents**Incidents relating to medical devices must be reported to the Medicines and Healthcare products Regulatory Agency (MHRA) as soon as possible.

Further information about reporting incidents; online incident reporting facilities; and downloadable report forms are available from MHRA’s website.

Further information about CAS can be found on the Department of Health website

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