Tube Systems; Surgical Procedure; Testing The Patency Of The Valve - miethke GAV Gebrauchsanweisung

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TUBE SYSTEMS

The GAV has been designed to ensure the
optimal ventricular pressure. It is available as a
shunt system or as individual valve units with
or without an integrated distal catheter (internal
diameter 1.2 mm, external diameter 2.5 mm).
Individual valve units should be used with ca-
theters of approx. 1.2 mm internal diameter and
approx. 2.5 mm external diameter.
The connector on the valve allows using ca-
theters of 1.0 mm to 1.5 mm internal diameter.
The external diameter of the catheter should
be about double the internal diameter. In any
case, the catheters must be carefully fixed, with
a ligature, to the valve connectors. Kinks in the
catheter have to be avoided.
The provided catheters have virtually no effect
on the Pressure-flow characteristics.

SURGICAL PROCEDURE

Positioning the ventricular catheter
Several surgical techniques are available for po-
sitioning the ventricular catheter. The necessary
skin incision should be carried out, preferably,
in the shape of a lobule pedicled towards the
draining catheter or as a straight skin incision.
To avoid CSF leakage, care should be taken
that the dura opening is kept as small as possi-
ble after applying the borehole. 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 bo-
rehole 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 borehole 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.
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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).
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, physiological
saline solution. The valve is patent if fluid can be extracted in this
way (see fig. 6).
Caution: Pressure admission through the single-use syringe
should be avoided, both at the proximal and the distal end.
Contaminations in the solution used for the test can impair the
product's performance.
GAV