Patency Test (Post-Operative); Patency Test Downstream Of The Reservoir (Valve And Distal Catheter); Sampling The Csf And Injection; Potential Causes Of Adjustment Difficulties And Suggested Measures - Sophysa Sophy Notice D'emploi

It is easy to read the pressures on a radiological image
(Figure 8).
F 8 – C
IGURE ONFIRMATION OF THE OPERATING PRESSURE
FILMS OF THE
®
On the Sophy valve the main pressures of the valve are
located by 1 radio-opaque point for Low pressure, 2 radio-
opaques points for Medium pressure and 3 radio-opaque
points for High pressure. Intermediate pressures are
determined by the position of the rotor in relation to these
radio-opaque markings for the main pressures.
Locate the valve inlet connector, wider due to the
presence of a nut.
The position for the lowest operating pressure (Position No.
1) is the position located nearest to this connector.
If the right-hand valve rotor micro-magnet is facing the
radio-opaque point nearest the inlet connector, the valve is
set at the lowest pressure (Position No. 1).
Then, moving clockwise away from the inlet connector,
each of the following positions corresponds to a higher
pressure.
The radio-opaque marking furthest away from the valve
inlet connector corresponds to the highest pressure
(Position No. 8).

9.6. PATENCY TEST (POST-OPERATIVE)

There are two steps for the post-operative test on the
patency of the shunt :
9.6.1. Testing the patency of the ventricular
catheter
NOTE
This control is possible with SM8A (antechamber) and
SM8B (burr hole reservoir) type models. For the SM8, SM3
type models, a ventricular catheter with reservoir must be
used.
Pinch the catheter with a finger just after the valve outlet
connector.
With another finger, press the reservoir to make the CSF
flow back into the ventricular catheter. A reservoir that
cannot be compressed easily or does not fill quickly may
indicate there is an obstruction in the ventricular catheter.
(X-
SM8 )
VALVE MODEL
9.6.2. Patency test downstream of the reservoir
(valve and distal catheter)
RAY
NOTE
This control is impossible with a SM8B type model (burr
hole reservoir) because there is no access to the ventricular
catheter upstream of the reservoir.
Pinch the catheter with a finger just before the reservoir,
then with another finger press the reservoir to push the
CSF through the valve and distal catheter. A reservoir that
cannot be compressed easily may indicate an obstruction
either of the valve or the distal catheter.
PRECAUTION
Do not rely only on the characteristics of the patency test to
diagnose an obstruction in the shunt system. Obstruction
of a shunt system can occur in any of its components and
should be diagnosed first of all by the clinical data and
additional examinations.

9.7. SAMPLING THE CSF AND INJECTION

Access to the CSF is obtained by pricking the reservoir
with a 24G (or smaller diameter) Huber needle.
The integral reservoir on the SM8A and SM8B models is
designed for occasional use.
Its watertight performance is reduced after very frequent
pricking into the dome.
— To inject in the proximal direction, compress the
catheter just after the valve outlet connector.
— To inject in the distal direction, compress the catheter
upstream of the reservoir.
NOTE
Elective injection in the distal direction is not possible with
a model of the SM8B type (burr hole reservoir) because
there is no access to the ventricular catheter upstream of
the reservoir.
Ensure that the base of the reservoir is not crossed with the
needle.
PRECAUTIONS
Do not inject into, or take samples from, the CSF without
having tested the shunt patency. Significant overpressure
could damage the shunt if it is known that there is an
obstruction.
Do not inject too fast or inject too great a volume. The
increase in pressure could damage the shunt.
Do not use a syringe with a volume of less than 10cc for
injections or taking samples. Too great a pressure could
damage the shunt.
9.8. POTENTIAL CAUSES OF ADJUSTMENT
DIFFICULTIES AND SUGGESTED MEASURES
Poor positioning of the Locator in relation to the centre
of the valve, or in relation to the valve's flow path, or in
relation to the flat surface/plane of the valve, may lead
to inaccurate reading of the operating pressure by
the Compass, and/or to difficulty adjusting with the
Magnet.
ENGLISH – 15