Valleylab CUSA EXcel-8 - A Common Misunderstanding of the Amplitude Setting

How the TISSUE Select Feature Works
A Common Misunderstanding of the Amplitude Setting
It has been common practice to decrease the amplitude setting when
encountering critical structures. The reasoning behind this practice is that
the lower amplitude setting results in slower fragmentation rate and
greater selectivity, thus greater control to help avoid damage when
dissecting near the critical structures. Look at this reasoning more
carefully.
True: Decreasing the amplitude setting also decreases the fragmentation
rate.
True: Because the fragmentation rate is slower, the surgeon has a little
more time to move the tip away from a critical structure before damaging
it; therefore, the surgeon sees to have greater selectivity and control.
False: The surgeon gains greater selectivity, thus greater control and
precision when dissecting near critical structures.
Why does the decrease in amplitude not give greater selectivity and p
control? Decreasing the amplitude does not greatly affect the reserve 5
power.
3
| ©
Figure
6-3.
>
Reserve power vs. amplitude setting 100% 4 e =
Te о
τος τὸ
A ©
E 80% 十 一 一 一 一 一 二 一 一 一 as 一 一 3
E M =
5 № 3
O M
È 60% Я |e Tip Stroke
る -e- Reserve Power
8 40% - 4
8
È
20% — - ーー
0%
100% 90% 80% 70% 60% 50% 40%
Amplitude Setting (Std)
Decreasing the amplitude leaves plenty of reserve power.
When the tip contacts critical structures, it still has more than enough
power to fragment them if the surgeon applies pressure or prolongs the
tip-tissue contact. Therefore, decreasing the amplitude setting gives the
following results:
* Reduced fragmentation ability
e Reduced fragmentation rate
e Little increase in selectivity
e Little reduction in reserve power.
CUSA
EXcel-8
System
Service
Manual
6-9