Click on Pics
to Enlarge
to Enlarge
Algos
Thermocoagulation Pulsed RF Neurotomy
Techniques
While the title appears to be an oxymoron, in fact high temperature pulsed
RF has been used for years outside pain management for the treatment of
metastatic tumors of the lung, kidney, liver, and bone. Pain management
however has taken a minimalist approach to pulsed RF, modulating the
energy so low that there is no lesion at all produced. It has been
demonstrated that pulsed RF at high temperatures tends to create a more
elongated lesion with the tip of the probe receiving far more energy than
with the continuous wave thermocoagulation RF with which we are all so
familiar. The first figure on the left demonstrates in a liver specimen
application of continuous wave RF at 80degrees C above and a pulsed RF 80
degrees C below. Clearly the lesion length is greater with the pulsed vs
continuous wave RF. Since the lesion is created to such a distance off the
end of the RF needle during high temperature pulsed RF (HTPRF), it follows
that a new approach may be possible to the medial branches. Instead of
the parallel vector approach as with continuous wave RF, the HTPRF is
performed orthogonal to the medial branch. Instead of the traditional
inferior to superior approach, the approach is superior to inferior with a 40
degree lateral to medial angulation. The target is the medial branch itself
on the anterior 1/4 of the transverse process. The trajectory is 40 degrees
rotation off the sagittal plane and 25 degrees cephalocaudad from the
horizontal plane. Once the TP is contacted, the needle is rotated across the
groove between the TP and SAP creating several lesions at 60sec/80 deg
C/20ms pulses. The machine used to create these lesions was a Stryker
until it began repeatedly shutting down in the midst of the procedure in
spite of the Stryker engineers assurances that the machine was designed
for this application and had been tested as such, however it is believed the
particular machine itself may be faulty and is being checked at the factory .
Current stock machines which will reliably create this lesioning parameter
are Owl and Bayless. Radionics and Stryker have the capability
theoretically of producing the lesions using these parameters but both
machines shut down after several lesions, ostensibly due to the power
spikes necessary to maintain an average 80 degree temperature
throughout the thermal dissipation period of the pulse sequence.
Neurotherm does not have the capability to do high temperature pulsed RF.
RF has been used for years outside pain management for the treatment of
metastatic tumors of the lung, kidney, liver, and bone. Pain management
however has taken a minimalist approach to pulsed RF, modulating the
energy so low that there is no lesion at all produced. It has been
demonstrated that pulsed RF at high temperatures tends to create a more
elongated lesion with the tip of the probe receiving far more energy than
with the continuous wave thermocoagulation RF with which we are all so
familiar. The first figure on the left demonstrates in a liver specimen
application of continuous wave RF at 80degrees C above and a pulsed RF 80
degrees C below. Clearly the lesion length is greater with the pulsed vs
continuous wave RF. Since the lesion is created to such a distance off the
end of the RF needle during high temperature pulsed RF (HTPRF), it follows
that a new approach may be possible to the medial branches. Instead of
the parallel vector approach as with continuous wave RF, the HTPRF is
performed orthogonal to the medial branch. Instead of the traditional
inferior to superior approach, the approach is superior to inferior with a 40
degree lateral to medial angulation. The target is the medial branch itself
on the anterior 1/4 of the transverse process. The trajectory is 40 degrees
rotation off the sagittal plane and 25 degrees cephalocaudad from the
horizontal plane. Once the TP is contacted, the needle is rotated across the
groove between the TP and SAP creating several lesions at 60sec/80 deg
C/20ms pulses. The machine used to create these lesions was a Stryker
until it began repeatedly shutting down in the midst of the procedure in
spite of the Stryker engineers assurances that the machine was designed
for this application and had been tested as such, however it is believed the
particular machine itself may be faulty and is being checked at the factory .
Current stock machines which will reliably create this lesioning parameter
are Owl and Bayless. Radionics and Stryker have the capability
theoretically of producing the lesions using these parameters but both
machines shut down after several lesions, ostensibly due to the power
spikes necessary to maintain an average 80 degree temperature
throughout the thermal dissipation period of the pulse sequence.
Neurotherm does not have the capability to do high temperature pulsed RF.
Note: This technique is investigational and should not be used in
clinical practice until there are efficacy studies and the technique has
been formally published. Its presentation here is solely for educational
purposes for what the future may hold in RF technology.
clinical practice until there are efficacy studies and the technique has
been formally published. Its presentation here is solely for educational
purposes for what the future may hold in RF technology.