Questions And Answers - Stryker Neuroform EZ Mode D'emploi

note: After tightening the RHV firmly, the introducer sheath
tip should not move when pulled gently. Failure to secure
the introducer sheath may result in premature deployment
of the stent within the microcatheter hub or difficulty in
transferring the stent.
note: Ensure that the introducer sheath does not move
while retracting the stent delivery wire. Movement of the
introducer sheath during stent retraction may indicate an
inadequately tightened RHV and may result in premature
deployment of the stent within the microcatheter hub.
19. If stent positioning is satisfactory, carefully retract the
microcatheter in a continous movement, while maintaining
the position of the stent delivery wire to allow the stent to
deploy across the neck of the aneurysm. The stent's distal
markers will expand as it exits the microcatheter. Confirm
deployed stent position.
note: Do not deploy the stent if it is not properly positioned
in the vessel.
note: The physician may attach the optional torque device
to the proximal end of the stent delivery wire, which may
facilitate handling and stabilization. Be sure to tighten the
torque device to secure the stent delivery wire. Do not use
the torque device to torque the stent delivery wire as it is not
designed to be torqued.
note: Do not use the stent delivery wire to push the stent
out of the microcatheter while deploying.
20. Prior to removing the stent delivery wire, position the
microcatheter distal to the stent to maintain access
through the stent. Remove and discard the Neuroform EZ™
Stent System.
21. Advance an exchange length guidewire through the
microcatheter.
22. Remove the 0.027 in microcatheter while maintaining the
position of the exchange length guidewire, and replace
with an appropriate microcatheter to begin aneurysm
embolization.
aneurysm Embolization
23. The aneurysm embolization can begin immediately.
Standard microcatheters accepting 0.25 mm (0.010
in), 0.36 mm (0.014 in), or 0.46 mm (0.018 in) guidewires
with distal tip ≤ 2F may be carefully placed through the
interstices of the stent to place embolic coils in the
aneurysm.
note: Carefully watch the stent markerbands when
passing through the deployed stent with embolic coiling
microcatheters to avoid dislodging the stent.
24. Perform a standard embolic coiling procedure using
accepted embolic coiling practices.

QUESTiOnS anD anSwErS

Q: What is the optimal position of the stent with respect to the
aneurysm?
A: Generally, try to position the stent so that each end of the
stent is secured in relatively normal areas of the parent
vessel. The stent will be more stable if each end of the
stent is anchored in at least 4-6 mm of normal vessel. For
example, for aneurysms located in the supraclinoid carotid,
it may be better to secure the stent by deploying the distal
end in the M1 (middle cerebral artery, first segment) than
trying to deploy it in the few millimeters between the
aneurysm and the ICA (internal carotid artery) bifurcation.
When deploying the stent, care should be taken to use
a view that best shows the parent vessel distal to the
aneurysm, so that the distal end of the stent can be
accurately deployed with respect to the aneurysm. This
view may be different from the view used to advance the
Neuroform EZ Stent System, or the view used as a working
position for aneurysm embolization.
Deploy the distal end of the stent as precisely as possible with
respect to the aneurysm neck to assure at least 4 mm of each
end of the stent lies along the parent vessel. Ensure accurate
measurement of the aneurysm neck so that, when the stent
is properly sized per Table 1, the proximal end of the stent will
deploy at the correct location, even if it is difficult to see it
because of curves in the vessel.
Q: Which stent size should I choose if I intend to place the stent in
a vessel that has a different diameter between the proximal and
distal ends of the stent? Example: Vessel increases from 2 mm
PCA (posterior communicating artery) to a 3.4 mm basilar.
A: Choose the stent sized for the larger vessel. In this example,
choose the 3.5 mm stent. This stent can be deployed safely in
the smaller PCA and will be well anchored in the basilar artery.
Q: Is there any problem with deploying the stent across a branch
vessel? Can the stent be safely deployed across the anterior
choroidal artery? What about lenticulostriate arteries or
perforators arising from the basilar?
A: No adverse events resulting from branch vessel occlusion or
emboli to "jailed" vessels have been observed in the limited
clinical study conducted on this stent (26 patients followed
through 6 months). Stents have been placed extending from the
M1 (middle cerebral artery, first segment) to the ICA (internal
carotid artery) without problems.
Q: A loop, or several loops, of a coil (especially a small diameter
coil such as 2 mm) are protruding through the interstices of the
stent, and I am unable to reposition it. What should I do?
A: If the risk of leaving part of the coil in the parent vessel is
unacceptable, place a second stent inside the first stent to pin
the herniated coil portion against the wall of the vessel. Three-
dimensional angiography using an orthogonal view (i.e., "down
the barrel") may be helpful to assess whether or not a coil
loop is inside the lumen of the stent, in the parent vessel, or
between the wall of the vessel and the stent. Strict attention to
heparinization and antiplatelet medication is important.
Q: I have accidentally started to deploy the stent, but it is not in
the location that I wanted. What should I do?
A: The safest course of action generally is not to try repositioning
the stent, but to continue to deploy the stent where it is, and
then deploy a second stent at the desired location. Safely
deploying a stent, even in an undesired location will minimize
vascular injury. Animal studies have demonstrated that the
stent endothelializes in less than 30 days.
Q: I misjudged the positioning of the stent and have deployed
it with one end adjacent to the aneurysm rather than in the
normal part of the parent vessel. What should I do?
A: Remove the Neuroform EZ Stent System from the
microcatheter while maintaining the position of the
microcatheter. Insert and deploy a second stent starting from
inside from the first stent to the normal portion of the parent
vessel (telescoping stents). The second stent should be of the
same diameter or larger than the first.
warranTY
Stryker Neurovascular warrants that reasonable care has
been used in the design and manufacture of this instrument.
This warranty is in lieu of and excludes all other warranties
not expressly set forth herein, whether express or implied by
operation of law or otherwise, including, but not limited to, any
implied warranties of merchantability or fitness for a particular
purpose. Handling, storage, cleaning and sterilization of this
instrument as well as other factors relating to the patient, diagnosis,
treatment, surgical procedures and other matters beyond
Stryker Neurovascular's control directly affect the instrument and
the results obtained from its use. Stryker Neurovascular's obligation
under this warranty is limited to the repair or replacement of
this instrument and Stryker Neurovascular shall not be liable
for any incidental or consequential loss, damage or expense
directly or indirectly arising from the use of this instrument.
Stryker Neurovascular neither assumes,
any other person to assume for it, any other or additional
liability or responsibility in connection with this instrument.
Stryker neurovascular assumes no liability with respect to
instruments reused, reprocessed or resterilized and makes no
warranties, express or implied, including but not limited to
merchantability or fitness for a particular purpose, with respect
to such instruments.
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nor authorizes
Black (K) ∆E ≤5.0