Testing The Patency Of The Valve - MIETHKE GAV Mode D'emploi

EN | INSTRUCTIONS FOR USE
To avoid CSF leakage, care should be taken
that the dura opening is kept as small as pos-
sible after applying the burrhole. The ventricular
catheter is stiffened by the introducing stylet
supplied with the product.
The GAV is available in different shunt variants:
When using a GAV SHUNTSYSTEM with burr-
hole reservoir or SPRUNG RESERVOIR, the
ventricular catheter is implanted first. Once the
introducing stylet has been removed, the pa-
tency of the ventricular catheter can be tested
by checking if CSF is dripping out. The cathe-
ter is shortened and the burrhole reservoir is
connected, with the connection secured with a
ligature. The skin incision should not be located
directly above the reservoir.
The GAV SHUNTSYSTEM with prechamber
or CONTROL RESERVOIR comes with a de-
flector. This deflector is used for adjusting the
position of deflection before implantation of the
ventricular catheter. The catheter is deflected;
the prechamber is put into place. The position
of the ventricular catheter should be inspected
again by postoperative CT or MR imaging.
Positioning the valve:
The GAV operates in different modes de-
pending on the patient's position. Hence it is
important that the valve is implanted paral-
lel to the body axis. A suitable implant site is
behind the ear. Following the skin incision
and the tunneling through the skin, the ca-
theter is pushed forward to the implantation
site chosen for the valve. If necessary, the
catheter is shortened and fastened at the
GAV by means of a ligature, taking care that
the valve does not lie directly under the skin
incision. The valve is marked with an arrow
pointing towards the feet of the patient (towards
the distal end or downwards respectively).
CAUTION
The catheters should only be blocked with a
sheathed clamp and not directly behind the
valve as they might be damaged otherwise.
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Positioning the peritoneal catheter
The access site for the peritoneal catheter is left
to the surgeon's discretion. It can be applied
e. g. para-umbilically in a horizontal direction
or transrectally at the height of the epigastrium.
Likewise, various surgical techniques are
available for positioning the peritoneal catheter.
We recommend pulling through the peritoneal
catheter, using a subcutaneous tunneling tool
and perhaps with an auxiliary incision, from the
shunt to intended position of the catheter. The
peritoneal catheter, which is usually securely at-
tached to the GAV, has an open distal end, but
no wall slits. Following the exposure of, and the
entry into, the peritoneum by means of a trocar,
the peritoneal catheter (shortened, if necessary)
is pushed forward into the open space in the
abdominal cavity.

TESTING THE PATENCY OF THE VALVE

Isotonic sterile sodium chloride solution
Fig. 6: Patency test
The GAV can be filled most gently by aspiration
through a sterile, single-use syringe attached to
the distal end of the catheter. The proximal end
of the valve is immersed in a sterile, physiologi-
cal saline solution. The valve is patent if fluid can
be extracted in this way (see fig. 6).
WARNING
Pressure admission through the single-use
syringe should be avoided, both at the pro-
ximal and the distal end. Contaminations in
the solution used for the test can impair the
product's performance.
GAV