Biomedical Engineering Reference
In-Depth Information
The rupture probability in the irst 5 years is
Group 1A : 0%.
Group 1P : 2.5% with an increasing rate of 0.5% per year.
Group 2A : 1.5% with an increasing rate of 0.3% per year.
Group 2P : 3.4% with an increasing rate of 0.7% per year.
The difference between groups does not change as the size of
the aneurysm increases. For sizes of 7-12 mm, the rupture rate in
ive years for Group A is 2.6% increasing at 0.5% per year; for Group
P it is 14.5% increasing at 2.9% per year; for sizes of 13-24 mm
Group A is 14.5% increasing at 2.9% per year and Group P at 18.4%
increasing at 3.7% per year; and for 25 mm and more Group A has
40% at 8% and Group P has 50% at 10% [10]. Rupture risk factor
relates with the size of the aneurysm, high blood pressure, smoking,
multiple aneurysms, rupture medical records, family records, and
aspect ratio. Genetic reproduction and inherent diseases increase
that factor too [12-22].
2.1.3 Treatments
2.1.3.1 Clipping
Clipping surgery is achieved using a microscope and is the most
conventional treatment for cerebral aneurysms. The patient
receives general anesthesia, then the skin is cut and the skull open,
after cutting the dura mater and using a microscope for surgery the
subarachnoid is separated. Then the aneurysm is delicately exposed
to place a clip on its neck.
Figure 2.1 shows the intra-operative appearance of an
unruptured aneurysm and the DSA image of the cerebral artery
before treatment. A large-size aneurysm is visible at MCA bifurcation
and marked with an asterisk. In the intra-operative photograph, the
large-size aneurysm is exposed and marked with an asterisk. Also
an intra-operative photograph after the clipping is shown as well
as the corresponding DSA image of the cerebral artery where the
aneurysm has disappeared. Figure 2.2 shows 3D-CTA images of
a ruptured aneurysm, the arrow points to a bleb that grew into a
right middle cerebral artery (Rt. MCA) aneurysm. Intra-operative
photographs show that subarachnoid hemorrhage produces the red
color in the surgical ield. The arrow points at a clot in the bleeding
part of the aneurysm. Post-surgery image shows the clip attached to
the aneurysm.
 
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