Erbe ERBOTOM ICC 350 M, Instruction Manual

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6-2
6.3 Operation
Basics
The NEUROTEST device in the ERBOTOM ICC 350 Z is used for intraoperative differentiation
of electrically stimulable tissue structures, for example the external sphincter during transurethral
resections (TUR) of the prostate. Here, an electric stimulation in the form of periodical current
pulses is applied to the tissue to be differentiated and any reaction of the stimulated muscle is
observed.
The possibility of localization of motor nerves and/or muscles using electric current pulses in
electrically conductive tissue structures G is based upon the physical circumstance that electric
current flows divergently into the tissue from the stimulation electrode E, i.e. the current dtensity
i in the tissue decreases as the distance increases from the stimulation electrode, i.e. inversely as
the square of the distance r.
Consequently, due to this physical condition, a localization of motor nerves and/or muscles is all
the more precise the smaller the intensity of the current I is. The implication of this for the
practical localization of electrically excitable tissue structures is that a relatively high current
intensity permits a fast but imprecise localization, and a relatively low current intensity allows a
more time-consuming but therefore more precise localization.
The application of current pulses during TUR
The current pulses can be applied monopolarly via a coagulation electrode. The current returns
to the unit via a neutral electrode applied to the patient for the TUR.
Form of the current pulses
The NEUROTEST device supplies square-wave current pulses with 50 ms pulse duration and
550 ms pause duration. The amplitude of the current pulses can be set to a maximum of 25 mA.
50 ms