Dr. Langer Medical TWISTER User manual

Nerve stimulator TWISTER
®
INSTRUCTIONS FOR USE
Softwareversion 1.19
Manufacturer:
Dr. Langer Medical GmbH
Fabrik Sonntag, Haus 4a
79183 Waldkirch
Germany

TWISTER
®
Softwareversion 1.19 Page 3 of 46 Version 1.19-4 / 2010-05-31
Table of contents
1 Intended use..................................................................................................................... 5
2 Common notes ................................................................................................................. 6
3 Installation ........................................................................................................................ 8
3.1 Software installation............................................................................................... 8
3.2 TWISTER
®
USB-driver installation......................................................................... 8
3.3 Sound interface setup............................................................................................ 9
4 Functional principals and operation .................................................................................10
4.1 Front side description............................................................................................11
4.2 Control outputs and inputs at the rear side of the device ......................................12
4.2.1 Description of the combination with third party devices .................................12
4.3 TWISTER
®
start up...............................................................................................13
4.4 TWISTER
®
shut down...........................................................................................17
5 TWISTER
®
operation.......................................................................................................18
5.1 Main window controls............................................................................................18
5.2 Main window indicators .........................................................................................27
5.3 Pulse shape editor ................................................................................................28
5.3.1 Drawing a new pulse shape ..........................................................................29
5.3.2 Changing an existing pulse shape.................................................................31
6 Basic safety instructions ..................................................................................................33
6.1 Follow all instructions in the instructions for use ...................................................33
6.2 Operator obligation ...............................................................................................33
6.3 User obligation......................................................................................................33
6.4 Dangers using the TWISTER
®
stimulator..............................................................34
6.5 Preventing electromagnetic interferences .............................................................40
6.6 Warranty and liability.............................................................................................40
7 Safety instructions ...........................................................................................................41
7.1 Symbols and declarations .....................................................................................41
7.2 Informal safety measures......................................................................................41
7.3 Personnel training.................................................................................................41
7.4 Safety measures during normal operation ............................................................42
7.5 Constructional changes at TWISTER
®
..................................................................42

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®
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8 Copy right....................................................................................................................42
9 User’s manual copying ................................................................................................42
10 Technical data.............................................................................................................43
11 Serial number design ..................................................................................................44
12 Disposal of waste ........................................................................................................44
13 Cleaning......................................................................................................................44
14 Service and repair .......................................................................................................44
15 Accessories.................................................................................................................45
16 PC performance requirements ....................................................................................45
17 Manufacturer address .................................................................................................46

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®
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1 Intended use
TWISTER
®
is a freely programmable electrical nerve stimulator to evoke biopotentials on the
human body.
TWISTER
®
is connected to a PC via USB link. The USB link is not considered application
part B and BF. It is double isolated from the patient outputs and power supply. The
controlling PC does not need a medical isolation.
TWISTER
®
has 4 stimulation outputs. Each channel can be selected via software. The pulse
intensity can be controlled by the software or by the quick access buttons at the front panel.
The TWISTER
®
operating user must be trained and familiar with the impacts of electrical
stimulation to the human body!
In addition to standard pulses, the operator can configure and store pulse shapes
graphically. Thus the stimulator TWISTER
®
can also be used for special diagnostic purposes
at human beings.
TWISTER
®
has been developed for nerve stimulation only. A different or exceeding use
does not apply to the term intended use. Dr. Langer Medical GmbH is not liable for harms
caused by a non-intended use.
Please consider implicitly the notes mentioned in article 6.4: Dangers
using the TWISTER® stimulator
The intended use is based on the compliance with the required service and maintenance
intervals.

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®
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2 Common notes
The exact attention to the instructions for use is the main requirement for the intended use
and the correct handling of the device and the resulting safety for the patient and the
operator.
It is not allowed to use accessories not approved with the device by the manufacturer and
not listed in the instructions for use. In case of any use of accessories not listed in the
instructions for use, the technical and biological harmlessness has to be proved.
All printed documents comply with the delivered devices and the current safety standards
when printed. All rights are reserved for the mentioned devices, circuitries, methods,
software programs and names.
The use of needle electrodes together with electro surgery devices can
cause an increased risk of burns at the contact between the electrode
and the skin. For this reason all advices and safety instructions of electro
surgery devices have to be studied carefully and followed by the users.
In addition, all devices measuring impedance or current have to undergo
an electrical safety check on a regular time frame.
Caution:
Needle electrodes should be applied as far as possible away from the electro surgery
devices to avoid burns caused by induced currents in result from radio frequency
fields. Thus the electro surgery device should not be placed close to the patient’s
head or neck in case of a surgery. All cables of these devices should be placed as far
away as possible from other electrode cables particularly using monopolar
instruments.

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Before starting surgery, the risk of injuries of the nerves to be examined
as well as burns caused by interactions between electro surgical devices
and the TWISTER
®
nerve stimulator, should be balanced.
Only those needle electrodes are allowed to be used which are approved for use with
TWISTER
®
by the manufacturer. In case non sterile electrodes are used with TWISTER
®
,
the needle electrodes must be sterilized. Before using the needle electrodes the user’s
instructions and in case of reusable electrodes the manufacturer’s sterilization directives
have to be studied carefully and followed up.
The same applies to the use of stimulation probes accordingly. Only those stimulation
probes provided by the manufacturer are allowed to be used. The stimulation probes must
be sterilized before each use following the user’s instructions and manufacturer’s sterilization
directives.

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®
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3 Installation
3.1 Software installation
Insert the TWISTER
®
software CD into the CD-Rom drive and follow the prompts of the
installation wizard. Please consider, that during installation of the software, the stimulator
TWISTER
®
may not be connected to the computer.
3.2 TWISTER
®
USB-driver installation
Please consider that for the USB-driver installation the TWISTER
®
has to be connected to
the PC which controls TWISTER
®
. To install the USB-driver for the nerve stimulator
TWISTER
®
, some configurations in the “Device Manager” have to be modified. The “Device
Manager” can be opened by the follwing path:
START Control Panel
System
Tab “Hardware”
“Device Manager”
Enlarge “Universal Serial Bus Controllers” and choose “Micronas USB Verbundgerät” in the
“Device Manager”.
Use the right-click to choose “Update Driver”. The Update Manager is opened.
Choose: “Yes, this time only”
Click “Next”
Choose: “Install from a specific list or specific location”
Click “Next”
Choose: “Don’t search, I will choose the driver to install”
Click “Next”
Choose: “TWISTER-HS”
Click “Next”


follow the instructions to finish USB-driver installation

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®
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3.3 Sound interface setup
For correct audio playback the sounds and audio devices have to be reconfigured. Therefore
switch to:
START Control Panel
Sounds & Audio Devices
Tab “Audio”
For “sound playback” the internal sound card must be set as default device.
NOT TWISTER-HS!
For “sound recording” the internal sound card must be set as default device.
NOT TWISTER-HS!
Please checkmark the box for “Use only default devices”!

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4 Functional principals and operation
The maximum voltage is +/- 200 Volts.
The operational indicator (READY) at the front panel of the TWISTER
®
shows, that the TWISTER
®
is ready to deliver stimulation pulses.
The electrode output is twice isolated against power supply and the control unit, consisting
of the trigger output, footswitch input and USB link and thus potential free.
Only those electrodes approved by the Dr. Langer Medical GmbH are allowed to be
connected to the electrode output.
The stimulation current density must not exceed 2 mA / cm².
Energy limitation:
TWISTER
®
monitors the energy delivered to the electrodes. The energy is measured at a
1000 Ohm resistance and limited to a maximum of 50 mJ. The exceeding will be signalized
by the software.

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®
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4.1 Front side description
Increasing stimulation current
Decreasing stimulation current
Stimulation start / stop, single pulse in footswitch mode
CH1/2: Connector for stimulation channels 1 and 2
CH3/4: Connector for stimulation channels 3 and 4
Power: Power supply indicator (switched on -> green)
Ready: Stimulator is ready to deliver stimulation pulses (yellow)
PC Link: PC connected, control software started (green)

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4.2 Control outputs and inputs at the rear side of the device
Power module: Power switch to turn TWISTER
®
on and off
USB-Host Connector: USB cable connector to PC
Footswitch: External footswitch connector
Trigger Out: TTL trigger output for connection to third party monitoring
systems
4.2.1 Description of the combination with third party devices
A third party monitoring device can be triggered via Trigger Out. The trigger out pulses are
time synchronously with the stimulation pulses. The trigger out pulse is fired with the first
pulse in burst mode!
USB-Host Connector :
The USB cable connecting TWISTER
®
to the controlling PC is connected to this connector.
The controlling PC must meet the minimum requirements described in chapter 16!
Footswitch:
A footswitch can be connected to this connector. The Footswitch must comply with
protection class IPX1. An approved footswitch can be purchased optionally from the
manufacturer.

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®
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4.3 TWISTER
®
start up
First start up
The operator must not start up the device before the manufacturer or dealer
-has checked the correct device function at the customer’s site,
-has introduced the responsible users in the correct operation of the device.
TWISTER
®
has to be started up as follows:
Use the power cable shipped with the device to connect it to the power supply. The power
supply connector can be found at the rear side of the device.
The TWISTER
®
device can be switched on now. The power switch is also located at the rear
side of the device. The green power LED at the front side indicates the correct operation.
The included USB link cable has to be connected to the „USB Host Connector“ at the rear
side of the TWISTER
®
. Regardless whether the controlling PC is switched on or off, the USB
link cable has to be connected to the PC.
The PC must have at least one unused USB link, PCs w/o USB connector cannot be
used for TWISTER
®
operation.
The stimulation cables are connected to the device’s front side. According to the desired
stimulation channel, one of the two patient output connectors have to be chosen. The
stimulation channel is finally selected by the software.
To trigger an external monitoring device a connection between the trigger output at the rear
side of the TWISTER
®
to the trigger input of the external monitoring device has to be
established.
Optionally an external footswitch can be connected at the rear side of the device. The
footswitch is used to fire single pulses.
Now the TWISTER
®
PC software can be started. After a correct installation the green LED
light “PC Link” at the front side of the TWISTER
®
indicates a correct operation.

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®
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The program’s main window opens (Figure 1) and signalizes the correct operation of the
system.
An error message will appear while programming the PC with non MS Windows 2000
Professional or MS Windows XP Professional system software (upon confirmation of
the error message the program will be aborted).
Figure 1: Main window
If the TWISTER
®
is not connected to the power supply or not switched on, the following error
message appears (Figure 2).
Figure 2: Error message, TWISTER
®
not connected to the power supply or switched off

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®
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Connect the power cable to the power supply and switch the TWISTER
®
device on. After
clicking the <No> button the error message will disappear. With <Yes> the program can be
closed.
If the USB device driver is not properly installed at the PC or if the USB link cable is not
connected or if the PC does not have a built-in sound board, the following error message
appears (Figure 3).
Figure 3: Incorrect USB device driver installation or USB link cable not properly connected
Connect (if applicable) the USB link cable to the connector at the rear side of the TWISTER
®
and to the PC’s USB connector. Then push the <No> button and the error message will
disappear.
If the error message continues to appear, contact the customer service of Dr. Langer
Medical GmbH.
If an error message according to Figure 4 appears, you have to adjust the PC’s audio setup.
Figure 4: Configuration error in the audio and multimedia setup

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®
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Therefore check the configurations made according to chapter 3.3: Sound interface
setup! If necessary redo the sound interface setup!
If the error message continues to appear, contact the customer service of Dr. Langer
Medical GmbH.
If TWISTER
®
is not connected to the PC via the USB link cable the TWISTER
®
software can
be started in DEMO mode by pushing the <Demo> button. This mode shows you a flashing
message „Demo-Mode“ at the bottom of the main window (Figure 5). To leave the demo
mode, the software must be closed by pushing the <Quit> button and restarted afterwards.
Figure 5: Demo mode

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®
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4.4 TWISTER
®
shut down
TWISTER
®
has to be switched off as follows:
The device is switched off using the power switch at the rear side of the device. The green
„Power“ LED light is turned off. If the PC is still switched on, the green „PC Link“ LED
remains on. This function can be compared to a sleep mode. By switching off the PC or
disconnecting the USB link cable the TWISTER
®
is switched off completely.

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®
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5 TWISTER
®
operation
5.1 Main window controls
The main window is divided in several control groups. Figure 6 shows the controls to setup
the pulse shapes for single and burst stimulation, the stimulation frequency as well as the
controls for sequential stimulation.
Figure 6: Controls in the upper left part of the main window
Frequency [Hz]: Stimulation frequency setup in the range of 1 … 1000 Hz
Pulse width [µs]: Pulse width setup in the range of 50 … 1000 µs
Polarity: Polarity setup of the rectangular stimulation pulse: positive, negative or
alternating (positive-negative). The pulse width in alternating mode is
the value for each of the both polarities. The complete pulse is thus
twice the selected pulse width long.
Pulse number: Pulse number setup in burst stimulation mode in the range of
2 …10. This control is disabled and dimmed when single pulse or
pulse shape is selected.
ISI [ms]: Interstimulus interval setup in burst stimulation mode in the range of
1 … 200 ms. The interstimulus interval is the break between two
subsequent pulses in burst stimulation mode.

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®
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Channel: Stimulation channel setup in the range of 1 … 4.
Please check the correct connection of the stimulation output
cable at connector 1 (CH1/2) for channel 1 or 2, or connector 2
(CH3/4) for the channels 3 or 4 at the front side of the TWISTER
®
.
Sequence: Switching sequential stimulation on or off. In this mode the selected
number of stimulation pulses will be fired. Afterwards the stimulation
pauses for the preselected time and will be restarted automatically
again. This mode of stimulation is particularly suitable for SEP. With a
sequential stimulation an additional display “Sequence Status:” will
appear with pulse number and break time in seconds (Figure 7).
Figure 7: Controls to setup sequential stimulation
A stimulation with frequencies less than < 1Hz can be configured in sequential mode.
Choose “1” in the field <Stimulations>. The value in the field <Break [s]:> is the time
period between two subsequent pulse sequences, in the case of one stimulation
between two subsequent single pulses.
Stimulations: Number of stimulations in a stimulation sequence in the range of
1 … 2000. If the checkbox <Sequence:> is not marked, the sequence
setup controls appear dimmed and disabled.

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®
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Break [s]: Time period between two subsequent stimulation sequences in the
range of 1 … 300 seconds. If the checkbox is not marked the <Break
[s]:> value is disabled and dimmed. Thus the running sequence stops
after the system has reached the number of stimulations the first time.
In the right part of the main window the controls for the stimulation current can be found. The
current can be changed in the range of 1 … 100 mA (Figure 8).
The controls labelled with arrows are used to increase or decrease stimulation current.
The double arrow buttons increase or decrease the stimulation current in steps of 1 mA,
single arrow buttons in steps of 0.1 mA.
At the TWISTER
®
front side you can also find two buttons labelled with arrows. They have
the same functionality as the double arrow buttons in the software interface. Holding down
the buttons for a long time increases or decreases the current continuously. A time delay
prevents rapid current changings.
Figure 8: Stimulation current controls
Because of safety reasons the stimulation current is set to 1.5 mA after starting the
software or a new program. The maximum current value can be configured and stored
together with the selected program. It is displayed in the yellow line above the signal
graph (Figure 7).