Use Instructions

ELST026-AUM001-V0.6.2 Page 10 of 68
1.1.2 Principle of Operation
The device consists of a table top control unit with a mains powered external D.C. power
supply, a hand piece to manipulate the needle and a return electrode. The control unit con-
tains a battery to allow operation without external power supply. The power supply is medi-
cal grade so it can remain connected during a treatment. It is used to charge the battery
and to operate the device, e.g. when the battery is low.
Apart from the socket for the power supply there is a socket for the return electrode lead
wire and one for the cable of the hand piece with the needle. A holder for that on the control
unit is provided, constructed in such a way that the operator is forced to dispose of the used
needle before putting the hand piece in it.
A colour display with touch screen provides the graphical user interface of the embedded
software. When there is no current flowing it can be set by the operator to deliver the re-
quired level of current with a linear ramp up and ramp down during an adjustable time, or
the current level can be adjusted via the touch screen or with up and down buttons on the
hand piece.
The software controls a D.C. current source that has enough compliance to deliver the re-
quired current even with a high resistance of the patient’s skin. When the return electrode is
attached to the patient and the needle is inserted, an A.C. voltage source delivers a minute
current with a frequency beyond 20 kHz. This is detected and enables the start of the cur-
rent pulse.
The operator attaches the return electrode to the patient near the area where the interven-
tion will be done. A sterile needle is clamped with its handle into the front of the hand piece
and pulled out of its packaging. With the transducer of the ultrasound imaging equipment
the injury is located and the needle inserted until its tip is in the pathologic area. Pressing
the start/stop button on the hand piece starts the D.C. current. Electrolysis will take place
when sufficient charge is delivered and the water molecules will be split in hydrogen and hy-
droxil ions. This is visualized as a full hyperechogenic zone by the ultrasound imaging equip-
ment. This is the signal to stop the current by pressing the start/stop button again. In case
it is uncomfortable for the patient the current can be stopped or reduced by the decrement
button on the hand piece. Or, when the pain tolerance of the patient is higher, it can be in-
creased by the increment button on the hand piece. So there is no need to let go of the
hand piece during the procedure. The device records the amount of the delivered charge
which is usually about 30 mC. The user is first made attentive when this value is reached
while a warning is issued when this value is seriously exceeded.
For dry needling of trigger points the maximum current is limited to 1 mA. The ultrasound
imaging equipment is not needed for this application. A short tiny muscle twitch is observed
via the needle when the trigger point tension releases. The A.C. auxiliary current is not
used.
The user can log the recordings of current level, duration and applied charge per session in a
patient database together with details on the disorder and progress of the treatment. This
will be a great source of data for clinical follow up studies (after anonymizing it of course).