Urgent: Device Recall
IMPORTANT PATIENT MANAGEMENT INFORMATION
Model 7428 Kinetra® and Model 7426 Soletra@ Implantable
Neurostimulators
October 2007
Dear Healthcare Professional,
The purpose of this letter is to advise you of a problem
with a subset of Model 7428 Kinetra® and
Model 7426 Soletra® implantable neurostimulators where
separation of internal connections
(lifted wirebonds) between the electronic circuit and
battery may lead to sudden cessation of
therapy. We are aware of two failures which led to adverse
events where hospitalization was
required because return of symptoms was severe.
Modification in drug therapy was also
required to control symptoms until a replacement device
could be implanted. No permanent
injury occurred. This letter also provides patient
management recommendations for this issue.
In March 2006, Medtronic identified 24 implanted Kinetra
devices in the United States and
Europe believed to be at risk for th is problem, which
prompted distribution of customer letters to
affected physicians. At that time, Medtronic estimated that
up to two of those 24 implanted
Kinetra devices may fail due to this problem. Since that
time, eight additional returned devices
were confirmed to have failed due to this problem (six of
which were outside the identified
population of 24 implanted devices). As a result of our
on-going monitoring and analysis of this
problem, Medtronic is expanding the March 2006 customer
communication to include all Kinetra
and Soletra devices with electronic circuits that were
cleaned with a particular cleaning solvent
during manufacturing in several specific time periods.
Sudden cessation of therapy due to any cause (e.g. normal
or premature battery depletion,
component failure) can result in the immediate return of
symptoms. Symptoms may be worse
due to rebound effect or the possible progression of the
disease since initiating Deep Brain
Stimulation (DBS) therapy.
• Symptoms specific to dystonia patients may include severe
and painful muscle spasms;
and for generalized dystonia patients, dystonic crisis.
• Symptoms specific to Parkinson's disease (PO) patients
may include severe tremor,
rigidity, bradykinesia, and akinetic crisis eventually
resulting in decreased mobility.
• Symptoms specific to Essential Tremor patients may
include a sudden return of tremor.
These symptoms may not be immediately responsive to
pharmacotherapy.
This anomaly will leave the device in a non-functional (no
telemetry, no output) or Power-OnReset
(POR) state. These states can be intermittent or permanent.
The patient cannot rely on
the patient programmer to identify this anomaly.
A device can be confirmed to be in the POR state through
interrogation of the device with the
physician programmer. A device in the POR state will have
its parameters reset to the factory
default settings with no stimulation output and its serial
number will be unavailable. While it may
1 of 3be possible to successfully reprogram an affected device
that is in the POR state, the device
may return to the POR state due to the intermittency of
this anomaly. Therefore, this anomaly
cannot be corrected permanently by reprogramming the
device.
Affected Devices
The specific model and serial numbers of affected devices
you are following or have implanted
are attached to this letter. A serial number look- up
application is also available on our web site
at KinetraSoletra.medtronic.com to confirm affected device
serial numbers.
• For Kinetra, there are approximately 1200 devices
worldwide that are affected by this
communication, with approximately 120 active implants in
the United States. To date, a
total of approximately 22,000 Kinetra devices have been
implanted worldwide.
• For Soletra, there are approximately 1860 devices
worldwide that are affected by this
communication, with approximately 1240 active implants in
the United States. To date, a
total of approximately 50,000 Soletra devices have been
implanted worldwide.
Root Cause
In the affected devices, separation of internal connections
has been observed between the
electronic circuit and battery. Electronic circuits used in
this subset of affected devices were
cleaned with a particular cleaning solvent during
manufacturing in several specific time periods
that could reduce the strength of the internal connections
over time.
A small number of devices manufactured outside these time
periods have exhibited this same
failure mechanism, and we attribute these failures to a
base level of random failures not
associated with any identifiable root cause.
Probability of Occurrence
As part of our ongoing returned product analysis, Medtronic
has calculated the following data
with regard to this failure mechanism.
DeVIces returned and analyzed by Medtronlc that were
confirmed to have thiS failure mechanism.
Number of
Confirmed* Implant Duration % Confirmed % Confirmed
Failures from of Confirmed Failures from Failures from
Subset Failures Subset Total
Population (months) Population Population
Kinetra 22 22 to 49 1.38 0.10
Soletra 31 18 to 39 1.29 0.06
*
There is no proactive testing that can predict which
devices may fail in the future. The
probability of device failure increases with implant
duration. For devices from the affected
populations that are still implanted and active, we
estimate the probability of failure to be
between 1.38% (confirmed Kinetra experience) and 2.52%
(Weibull prediction model) after 5
years of implant duration. The total number of additional
device failures is estimated to be as
many as 31 Kinetra devices and 47 Soletra devices. These
estimates include a diverse patient
population and variability in implant locations.
Recommendations
We realize that each of your patients is unique, and we
support your clinical judgment in caring
for them. To assist physicians in their patient care,
Medtronic convened a medical advrsory
board composed of leading Lhited States and European
neurologists and neurosurgeons that
provided support in developing the following
recommendations:
• Consider the potential for this anomaly if your patient
presents with a device in a nonfunctional
(no telemetry, no output) or POR state.
• Consider informing your patients of this risk and advise
them to seek attention
immediately if they experience a return of pre-implant or
more advanced symptoms.
• Determine whether prophylactic device replacement is
warranted based upon
consultation with your patient, including review of the
patient's medical history. The
following considerations may be helpful for your decision
making:
o The length of time the device has been implanted.
o The patient's current Iifesty'le (e.g. participating in
extreme sports, extensive
traveling, operating machinery).
o For PO patients, the potential utility of rescue
pharmacological treatment.
o The risk of recurrent or worsening symptoms, particularly
for generalized
dystonia patients.
o The relative risks of abrupt cessation of stimulation
versus the risk of a device
replacement surgical procedure (e.g. risk of infection and
consequent delay of
reinitiating DBS therapy).
• Report any malfunction, removal and replacement to
Medtronic and FDA using the
medical device reporting system,
http://wwwJda.gov/medwatch/how.htm. Return
explanted devices to Medtronic for analysis.
Medtronic is communicating this information to the
appropriate regulatory agencies.
For Assistance
In the United States, contact Medtronic Neuromodulation
Technical Services at 1-800-707-0933
or your local Medtronic representative. Outside of the
United States, contact your Medtronic
representative. This information can also be found on our
web site at
www.MedtronicConnect.com. •
We appreciate your assistance with this matter and regret
any inconvenience this may have
caused you or your patient.
Sincerel¥,
George Aram
Vice President Quality
Medtronic Neuromodulation
30f3

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