Anterior communicating artery aneurysm clipping

Anterior communicating aneurysms are the most common intracranial aneurysms, accounting for about one-third of all intracranial aneurysms, but in our report, they are less than the posterior communicating aneurysms. The arterial structure of the anterior communicating artery region is complex. It may be related to the following arteries when dealing with aneurysms: 1 left and right anterior segment of the anterior cerebral artery (A1); 2 anterior communicating artery; 3 hypothalamic artery (2 to 5) 4 left and right anterior cerebral artery distal segment (A2); 5 left and right Heubner return artery; 6 left and right frontal iliac artery; 7 left and right frontal artery; 8 originating from the proximal segment of the iliac artery; 9 third branch A2. Complex vascular relationships create difficulties for surgery. There are also many variations in the origin of these arteries, which are often unclear in surgery. Anterior communicating aneurysms occur at the distal horn of the junction of the anterior cerebral artery and the anterior communicating artery. In 80% of patients with anterior communicating aneurysms, the anterior cerebral artery A1 segment diameter is not equal. Due to the impact of blood flow, aneurysms mostly occur on the larger side of the A1 segment, and only 2% of patients with aneurysms occur on the smaller side of the A1 segment. Yasargil reported 375 cases of anterior communicating aneurysm, 52.5% occurred at the junction of left A1 and anterior communicating artery, 28.8% occurred at the junction of right A1 and anterior communicating artery, and 18.7% occurred in the middle. There are also many anatomical variations in the anterior communicating artery itself, which should be noted when dealing with aneurysms. The apex of the anterior communicating aneurysm can be pointed in the following directions: 1 pointing to the front (12.8%), ie, the chiasm or saddle nodule, and possibly sticking to it; 2 pointing upwards (22.7%), located in the longitudinal fissure between the hemispheres on both sides For example, from the pterional approach, the contralateral A2 segment and the return artery may be obscured, and the frontal and frontal arteries may adhere to the tumor; 3 points to the rear (34.4%), located between the two sides A2; Lower endplate (14.1%); more than 5 directions (16%), the tumor is multi-lobed, and the top of the tumor points in more than two directions. See the image of the anterior communicating aneurysm. Treatment of diseases: intracranial aneurysms Indication Anterior communicating aneurysm clipping is applicable to: 1. The anterior communicating aneurysm is mildly ill, belonging to Hunt and Hess grade I to III, and can be operated within 3 days. 2. The anterior communicating aneurysm is severely ill, and belongs to the IV to V grade. The operation is performed when the condition is stable or improved. 3. If a life-threatening intracranial hematoma occurs after the rupture of the anterior communicating aneurysm, surgery should be performed immediately. 4. Unexplained anterior communicating aneurysm that was discovered by chance. Contraindications 1. The anterior communicating aneurysm is critically ill and is in a state of sudden death (Grade V). 2. Patients with severe cerebral vasospasm and cerebral edema after rupture of aneurysm may be postponed. 3. The patient has severe systemic diseases such as heart disease, diabetes, kidney disease, lung disease, etc., and can not tolerate craniotomy. Preoperative preparation 1. CT head scan, observe the distribution of blood in the subarachnoid space, paying special attention to the presence or absence of hemispheres. 2. Whole cerebral angiography, pay attention to the size of the A1 section of the tube on both sides, as a reference for selecting the side of the approach. At the same time, the contralateral carotid artery was compressed during one-sided carotid angiography to observe the collateral circulation function of the anterior communicating artery. Surgical procedure Wing point approach (1) The method of incision and craniotomy is the same as that of posterior communicating aneurysm. Since the anterior communicating aneurysm is located in the midline, it can be reached from the left or right wing point approach. Generally, the right-handed doctors enter from the right side. The following conditions should be entered from the left side: 1 In addition to the anterior communicating aneurysm, there is still an aneurysm in the left internal carotid artery or middle cerebral artery, which can clamp multiple aneurysms in one approach; 2 there is a larger in the left frontal lobe The hematoma needs to be removed; 3 the larger aortic aneurysm grows from the junction of the left anterior cerebral artery and the anterior communicating artery, and the top of the tumor points to the right side, such as the inability to separate the neck from the right side; Larger, it is the main blood supply artery of aneurysm. In order to control the rupture of aneurysm during surgery, it can be accessed from the left side; 5 left-handed doctors think that it is easy to operate from the left side. (2) Exposing aneurysm: entering along the lateral fissure, cutting the arachnoid on the frontal side of the lateral fissure, separating the lateral fissure from the medial side, opening the carotid artery pool, and releasing the cerebrospinal fluid from the optic chiasm. If the brain is not satisfied, the Liliequist membrane can be cut between the internal carotid artery and the optic nerve, and the cerebrospinal fluid in the pool between the feet of the brain can be released, and a satisfactory exposure can be obtained. The internal carotid artery is found on the outside of the optic nerve and is searched backward along the internal carotid artery to reach the bifurcation of the internal carotid artery. For example, the intracranial segment of the internal carotid artery is very short, and the A1 segment of the anterior cerebral artery is relatively straight, and it is easy to separate inward along the A1 segment to reach the anterior communicating artery region. If the internal carotid artery segment is long and the A1 segment is curved again, only a part of the A1 segment is exposed, so as to temporarily control the bleeding when necessary, without completely separating the entire segment of the A1 segment. (3) Separation of aneurysms: If the apex of the anterior communicating aneurysm points to the front or the bottom, the aneurysm can be seen by separating the optic chiasm and opening the endplate pool. The aneurysm is separated from the optic chiasm and the aneurysm is revealed using separation techniques. If the top of the aneurysm points upward or backward, the straight back of the frontal lobe should be cut and removed to reveal the aneurysm. The incision site is surrounded by the following structure: 1 the boundary line between the optic nerve and the frontal lobe (or the boundary line between A1 and the frontal lobe); 2 olfactory nerve; 3 frontal iliac artery. This area has a triangular or quadrangular shape and the length of the cut is about 1 cm. First, the blood vessels on the pia mater are electrocoagulated, the pia mater is cut, and the brain tissue is aspirated until the pia mater and the arachnoid membrane on the inner side of the frontal lobe. There may be adhesions and blood clots, which should be carefully separated and aspirated. The vascular and aneurysm are composed of the anterior communicating artery complex. Because of the different orientation of the aneurysm, the operation when separating the aneurysm is also different. The aneurysm with the top of the tumor pointing to the front is located above the optic chiasm. The frontal lobe can be seen and the top of the tumor can be adhered to the optic chiasm or saddle nodule. Sometimes there is an arachnoid between the aneurysm and the optic chiasm. There is an interface between them, which is easy to separate. Sometimes the adhesion is tight and it is difficult to separate. In this case, it is not necessary to separate them to cause the aneurysm to rupture. The left A1 segment is often covered, and the left A2 segment can be revealed first, and the anterior communicating artery is reversely separated, and the left A1 segment is revealed here. Aneurysms with the top of the tumor pointing upwards are easier to expose, and some aneurysms are covered back directly and need to be cut open. The contralateral A2 proximal segment and the Heubner return artery can be covered. The distal segment of A2 can be separated first, and the anterior communicating artery region can be reversely separated. The aneurysm can be pushed forward slightly to see the anterior communicating artery region. Push forward to see the relationship between the left A2 and the anterior communicating artery. The aneurysm with the top of the tumor pointing to the rear is revealed by incision and straight back, but the left A2 is often obscured, and the aneurysm needs to be pressed down slightly to reveal. Aneurysms often adhere to the frontal or frontal arteries. Normally, cutting the frontal artery does not cause adverse consequences, but the frontal artery should be preserved as much as possible. The aneurysm with the top of the tumor pointing downward points downward to the hypothalamus. It is easy to expose A1 and A2, but it is easy to injure the hypothalamic artery. These small perforators can be located in front of or behind the aneurysm. Damaged or clipped together. (4) Clip aneurysm: also need to operate according to the direction of the aneurysm. The aneurysm with the top of the tumor pointing to the front, after separating the aneurysm, select the appropriate tumor clip, open the tumor clip blade, one piece extends between the neck and the optic chiasm, and the other piece is above the neck of the tumor. The anterior communicating artery is parallel and slowly clamped (the hypothalamic penetrating artery is behind the artery and is not clamped). After clipping, the tumor capsule was punctured with a fine needle to verify that the clipping was complete. The aneurysm with the top of the tumor pointing upwards often needs to be cut open and the aneurysm is revealed in the longitudinal fissure on the medial side of the frontal lobe. The tumor clip is parallel to the anterior communicating artery and the neck is clamped. The aneurysm with the top of the tumor pointing to the back needs to be cut straight to reveal the aneurysm, and the neck is separated between the two sides A2. The hypothalamic perforating artery is located behind the tumor. To avoid mis-clamping, it is best to separate the posterior aspect of the aneurysm, push the tumor forward, separate it from the hypothalamic perforating artery, and then clip the neck. The aneurysm with the top of the tumor pointing down is often located under the anterior communicating artery complex, and the hypothalamic perforating artery passes over it. The tumor clip needs to pass through the gaps of the arteries and carefully avoid the hypothalamic perforating artery to clamp the neck. In the case of a complex aneurysm, the top of the tumor may point in any direction between the above directions, or may be multi-lobed in multiple directions. Dealing with this aneurysm should take a different approach depending on the situation. Bipolar coagulation narrows the neck of the neck, helps identify the neck and facilitates clipping, and sometimes requires multiple tumor clips or a looped (window) tumor clip to completely clip the neck. Those who cannot be clipped can be treated by other methods, such as the tumor wall reinforcement method and the thrombus occlusion method. Yasargil uses a "gradual clipping method" in the treatment of anterior communicating aneurysms, which can clamp a complex aneurysm. 2. Interhemispheric approach (1) Incision: Coronal incision or semi-coronal incision, the incision is hidden in the hairline. Some people also made a transverse incision along the skin wrinkles outside the frontal hairline. (2) Craniotomy: The skull is drilled with 4 holes, and the first hole is drilled in the middle line. Because there is an epiphysis under it, it is difficult to pass through the wire saw guide. The second hole was drilled to the left of the sagittal sinus, the third hole was 3 cm to the right of the sagittal sinus, and the fourth hole was 3 cm above the midline. It can also be opened with a 3cm diameter trephine with its center to the right. (3) Incision of the dura mater: The dura mater is cut along the edge of the bone window and turned over to the sagittal sinus. (4) Exposing an aneurysm: Pull the brain to the right side and leave it from the superior sagittal sinus and cerebral palsy. At this point, you can encounter two problems: 1 brain bulging is not easy to retract, and the difference from the pterional approach is that you can not open the brain pool to release cerebrospinal fluid, only puncture the ventricle to drain the ventricle; or slowly absorb the longitudinal The cerebrospinal fluid that flows out of the cleft and the corpus callosum should be patient and not force the brain tissue to cause trauma. Under microscopic operation, the aneurysm can be revealed by simply pulling the brain away from the sagittal sinus 1.5 to 2 cm. 2 Sometimes electrocoagulation is required to cut off 1 to 2 bridge veins that flow into the sagittal sinus. Gradually deep along the longitudinal fissure, the periorbital arteries on both sides can be seen before the corpus callosum, and the reverse detachment can reach the anterior communicating artery region, which is about 6 cm deep from the dural incision. This approach is easy to reveal the A2 segment on both sides, but can not reveal the A1 segment first. Sometimes it is necessary to absorb a part of the brain tissue to see the A1 segment. Therefore, when the aneurysm ruptures prematurely, the A1 segment cannot be controlled to stop bleeding. . However, this is less common in microsurgical operations. This approach is easy to expose aneurysms, especially the arteries pointing to the front, the top and the back of the tumor. It is also easy to remove the hematoma in the medial and frontal lobe and avoid damage to the olfactory nerve. complication Cerebral ischemia In the operation, the arteries that constitute the anterior communicating artery complex or the perforating artery from these arteries are mistakenly clamped, which may cause ischemia in the blood supply area and cause nerve dysfunction. 2. Electrolyte disorders Injury or ischemia of the hypothalamus can cause electrolyte imbalance, such as hypernatremia or hyponatremia syndrome, diabetes insipidus. 3. Mental symptoms Transparent septal ischemia can cause Korsakoff's syndrome. The patient is conscious, but shows signs of memory deficiency, confusion, and fiction. Some are temporary and some are permanent. Norlén reported surgical treatment of 33 cases of anterior communicating aneurysms, and 17 (51.5%) developed Coxsack's syndrome, of which 5 (15.2%) were permanent. Yesargil reported 375 cases of anterior communicating aneurysm surgery, 71 (15.9%) had temporary psychiatric symptoms after surgery, and 5 (1.3%) had permanent abnormalities.