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1.
Can
you confirm that the Digitimer D185 has now received clearance
from the FDA for marketing in the USA?
Yes,
in October 2002 Digitimer announced that the D185 was approved for
marketing by the FDA. The D185 is now the ONLY device
approved by the FDA for transcranial stimulation during
intraoperative MEP monitoring. Extensive use of the D185 all
over the world has demonstrated that it provides a safe and
effective way to reduce the incidence of paraplegia in spinal
surgery or surgical cases involving temporary occlusion of spinal
blood flow. A press
release is available on our website which provides further
information.
2.
I
see that the D185 has now become the D185 Mark II, what changes
have been made to the instrument?
The
new D185 Mark II now incorporates a number of enhancements which
have been added in response to user feedback. The front
panel now includes a polarity reversal switch, a multi-turn
control dial for setting the output voltage and rear panel
switches to alter the trigger settings. This latter feature
means that the stimulator can be set up with different EP
systems without having to open the case and make internal
adjustments. Finally, the new model includes special
circuitry to reduce stray mains (line) frequency pickup below
perceptible levels.
3.
I
am intending to use the D185 Mark II with a D185-HB3
electrode connection headbox for an upcoming scoliosis surgery but
I was wondering how the polarity switches on the stimulator and
the one on the D185-CB1
will interact with each other?
When
the D185 Mark II and the D185-CB1 are connected, both methods of
reversing the stimulus polarity will operate. For example if
both the D185 and D185-CB1 are set to reversed polarity, then the
output will have NORMAL polarity. Digitimer suggest that if
you are using the D185 Mark II along with a D185-CB1, you should
leave the D185 front panel switch set to normal polarity (flick
switch to the left) and only use the D185-CB1 to change it.
4. I
am thinking of purchasing a D185 for intraoperative monitoring,
what accessories is it necessary to purchase?
This
is very much a decision that only you as the user can make,
however we do supply a range of different accessories which start
with the basic D185-HB4 which is essentially an output extension
lead and end with the D185-HB3 which has 5 pairs of output
sockets, a means of isolating SEP recording electrodes during MEP
stimulus and a handheld trigger/polarity switching unit (D185-CB1)
which allows the operator to easily trigger the D185. More
detailed information on the accessories is available on the main D185
page. 5.
As I want to continue to record SEPs while stimulating
transcranially with the D185, I am worried that the stimulus
artefact from the D185 will saturate my EP system inputs?
Is there any way to prevent this from happening? Yes,
the D185-HB3 was specifically designed with this problem in
mind. The D185-HB3 headbox incorporates 5 pairs of MEP
output sockets as well as 6 channels of isolation for SEP
electrodes. If the SEP electrodes are connected through the
D185-HB3, they are briefly isolated while an MEP stimulus is
passed. This prevents the EP system from "seeing"
the MEP stimulus artefact and thus stops the amplifier from
saturating/blocking for any length of time. You can read
more about the D185-HB3 on the D185
page.
6.
Recently, when testing
a D185 MultiPulse, with an electrode extension cable I found that the stimulus was only passed intermittently in
response to pressing of the front panel trigger button. Do
you think there a problem with the stimulator or cable?
Before
you suspect any faults with the stimulator or cable, you should
confirm that you have inserted the moulded plug of the extension
cable correctly into the output socket on the front of the
stimulator. When the plug mates with the output socket, it
can be partly inserted with very little force, however, this does
not provide a good electrical connection. For a complete
electrical connection, further force is required and this supplement
to the D185 users manual illustrates how the plug should
be correctly inserted.
7.
I have recently had problems with the error light coming on when I
try and apply a train of many pulses at higher voltages. Is
there something wrong with my D185? The
D185 has certain safety limits that prevent excessive energy from
being delivered to the patient. If you set the D185 to
Normal mode and try to deliver too many pulses at too high a
voltage, the unit will give an ERROR. You should consult the
section titled Operating Modes in the D185 Operator's Manual where
you will find a graph that illustrated what these limits are.
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