Intracranial aneurysm is a local abnormal bulge of the intracranial artery lumen, which mostly occurs in the arterial ring and its main branches at the base of the brain. Direct surgery is the main method for treating intracranial aneurysms. With the development of endovascular interventional therapy in recent years, endovascular embolization has become the main method for treating aneurysms. Microcatheter shaping is one of the most basic techniques for intracranial aneurysm embolization and is also the core of intracranial arterial embolization. The success of microcatheter shaping is a necessary prerequisite for successful aneurysm embolization.
Basic principles of microcatheter shaping:
The principle is that the polymer at the end of the microcatheter dissolves when exposed to heat and solidifies when exposed to cold. Factors affecting microcatheter molding: shaping needle angle, fumigation time, and catheter type. Rebound: Pull out the shaping needle and the microcatheter will rebound. Usually the angle between the shaping needle and the target angle is 2:1. The passive shaping of the microcatheter is affected by the coaxial microguidewire, blood temperature, and the true three-dimensional shape of the parent artery.
The basic goals of microcatheter shaping:
Good deployment: the microcatheter is natural, has good compliance, and does not top the wall;
2. Effective support: the establishment of good access, the microcatheter's own supporting force, the use of the adjacent parent artery vessel wall, avoidance of excessive plastic bending, and avoidance of frequent repeated plastic bending.
The influence of vascular factors on microcatheter shaping:
The angle between the aneurysm and the parent artery;
The influence of the bend on the proximal side of the tumor neck on the microcatheter: the relationship between the two bend angles and the distance between the two bends;
The morphology of the aneurysm itself;
Whether to use assistive technology such as dual microcatheters.
Several ways of shaping microcatheters:
Single-bend shaping: The proximal parent artery is long and has a gentle curvature. The aneurysm and the parent artery are at a certain angle. The plane of the parent artery and the plane of the aneurysm and the parent aneurysm are in the same plane. The top of the aneurysm faces backward and downward. Communicating artery, middle cerebral artery with aneurysm top downward;
S-shaped bend shaping: The angle between the tumor body and the parent artery is opposite to the bend of the proximal parent artery, such as the middle cerebral artery with the tumor body pointing upward;
Z-shaped and J-shaped bend shaping: Z-shaped is actually an evolution of S-shaped bend, but the distance between the two bends is shorter compared to S-bend, such as an aneurysm at the beginning of the A1 segment of the middle cerebral artery;
Spiral shaping: The bend at the aneurysm neck and the bend on the proximal side are in the same direction, but the angles of the two bend planes are different, and the distance between the two bends is very short, such as the origin of the superior hypophyseal artery and the intrafossa artery;
Double microcatheter, single bend shaping.