NeuroTherm NT1100 Operator's Manual page 86

Figure 10.7
There is very little conclusive research to date on the mode of action of PRF. A few preliminary
studies have shown that a modification of CFOS and DNA expression has been observed in cells
of rat DRG after exposure to PRF. However, additional basic research needs to be done to come
to any good scientific conclusion as to the mechanism of action of PRF. References for the
available research today are contained at the end of this chapter.
In this era of evidence based medicine, pulsed radiofrequency has not yet been validated.
Several retrospective studies and audits have been conducted and the initial results are positive.
Because of a lack of uniform treatment guidelines, the anecdotal results for pulsed have ranged
from magnificent to abysmal. It is this author's belief that standardization of many of the PRF
parameters will at worst result in uniform treatment for all patients and at best significantly
improve the clinical outcomes. In any case, controlled clinical studies are long overdue for this
potentially promising modality.
When the study of PRF began, the parameters were arbitrary. For the voltage, a value is taken
that was within the range of the voltage during the initial heating phase of an RF heat lesion. The
values of 20 milliseconds on time and 480 milliseconds off time were chosen because they were
thought to provide good conditions for preventing heating above 42 degrees Centigrade. The
initial choice of 120 second duration of the procedure was completely arbitrary, and it was just
taken as a starting point. With no scientific basis, these parameters have been arbitrarily
modified by clinicians and thus there is no consensus as to what the optimum parameters are.
One of the major variables in pulsed radiofrequency treatment is the voltage level when the
pulses are "on". This arises from the desire to keep the temperature below 42 degrees C. if 42
degrees C. is reached, it is necessary to either manually or automatically reduce the pulsed
amplitude or the pulsed duration in order to ensure the temperature does not exceed 42 degrees.
Using the pulsed dose method, every pulsed is insured to be of the same amplitude and duration.
It is explained in detail in the following paragraph
10.1.3 The Pulse Dose Concept.
Whenever Pulsed RF is used, if your selected temperature limit is reached, the pulse must be
modified in some way to prevent the selected temperature limit from being exceeded.
1. Modify the pulse amplitude of the pulses- i.e. if a 45 volt amplitude was set, and if the
temperature limit was set to 42 degrees and was reached, the next pulses will be reduced to
prevent the temperature from increasing above the 42 C temperature limit.
2. Modify the pulse width whenever the temperature limit was reached, thus insuring that
each pulse delivered was the full set voltage amplitude.
In Pulse dose one and two above is no longer done. You ALWAYS give a FULL pulse, i.e. if
your settings is 45 volts amplitude for 20 milliseconds, you will always deliver this pulse amplitude
and duration. If the set temperature limit is reached, the generator will wait until the temperature
drops below the set temperature limit, it will give a FULL amplitude and duration pulse.
Because you are delivering only full pulses, in this mode you set the number of pulses that is
desired for the procedure as opposed to procedure time, since procedure time can vary
depending on whether the set temperature limit was reached.
Document 109.00
NEUROTHERM RADIO FREQUENCY LESION GENERATOR
OPERATORS MANUAL
®
MODEL NT1100
10September2012 Issue 06
10-6