14
VI.
SURGICAL DESCRIPTION AND USE
6.0
LEARNING TO USE RADIOSURGERY
®
Before making contact with the tissue, the power intensity must be selected and the foot
pedal or fingerswitch must be activated. During the actual cutting, it is important to use a
smooth uninterrupted motion with even and light manually applied pressure. The
movement should not be too slow. If it is, the build-up of lateral heat in the tissue may
cause charring, followed by necrosis and sloughing (see Preoperative Cutting Practice
Section 6.1). When performing a second or third cut in the same surgical site, allow
approximately ten seconds for the tissue to cool between applications of the electrode to
the site. Radiosurgery
®
should be regarded as a new technique that will require learning
of new skills. All rules of good surgical technique and clinical judgment still apply.
The biggest difference to be learned is that, unlike a steel scalpel or standard
electrosurgery, radiosurgery does not use manually applied pressure to cut. Therefore,
a light, smooth, continuous, and brush-like stroke should be developed. Only then will
the surgeon appreciate the tremendous advantages inherent in Radiosurgery
®
.
Defining Good Technique: Tissue damage will occur if heat is allowed to accumulate to
the point where excessive dehydration occurs. Preventing the accumulation of such
heat is a basic objective of radiosurgical technique. The spread of lateral heat in tissue
depends upon various factors as indicated in the following formula:
Time x Power
Lateral Heat
∝
–––––––––––––––––
Frequency
Additionally the electrode type and selected waveform impact the thermal build up.
This formula may be broken down in the following manner:
A.
Time
of Electrode Contact
a. The slower the passage of the electrode, the greater the lateral
heat.
b. The more rapid the passage of the electrode, the less the
lateral heat.
B.
Power
Level
a. If power is too high there is a high accumulation of heat.
b. If power is set correctly, lateral heat reduced to the minimum necessary to volatize
tissue cells. Smooth flow through tissue with no sparking and no resistance through
tissue.
c. If power is set too low, drag is observed causing excessive contact time and
bleeding due to tissue being pulled and torn from its base.
C.
Frequency
– Tissue provides lower resistance to higher frequencies, reducing thermal
build up.
D.
Electrode
Type
a. A broader electrode tip requires more power and creates greater
thermal spread.
b. A narrower electrode tip requires less power and creates less thermal
spread.
E.
Nature
of the Waveform - See Section 5.1 for details
a. Fully Filtered (Continuous Wave - CW) - Least lateral heat.
b. Fully Rectified - Low lateral heat.
c. Partially Rectified - High lateral heat.
d. Fulgurate - Highest lateral heat.
