basilar artery bifurcation aneurysm clipping

The basilar artery bifurcation aneurysm occurs at the apex of the basilar artery and is divided into bifurcations of the posterior cerebral arteries. It accounts for 2.9% to 5% of all intracranial aneurysms and 51% to 62% of vertebral-basal artery aneurysms. It is one of the more difficult parts of direct surgery for intracranial aneurysms. Treatment of diseases: intracranial aneurysms Indication Basilar artery bifurcation aneurysm clipping is applicable to: 1. A ruptured or unruptured basilar artery bifurcation aneurysm, with good condition and general physical condition, can withstand craniotomy. 2. A life-threatening intracranial hematoma is combined with an aneurysm rupture. Contraindications 1. The patient is critically ill after rupture of the aneurysm, or is in poor physical condition and cannot tolerate craniotomy. 2, aneurysm surgery is difficult, early surgery is also a greater risk, the timing of surgery can be appropriately postponed. Preoperative preparation 1, should emphasize the whole cerebral vascular digital subtraction cerebral angiography, because the surgery to facilitate the display of aneurysms have to cut off the dysplastic brain artery ring composed of the arteries, so the anatomy of the cerebral artery ring should be fully understood before surgery. 2. Perform a detailed physical examination to estimate the patient's ability to withstand surgery. 3, relieve the patient's fear of surgery, sedatives before the operation to prevent the patient from rupture of the aneurysm due to preoperative emotional stress. 4. Wash the scalp one day before the operation, shave the hair on the morning of the operation, wash and disinfect the scalp, and wrap it in a sterile towel. 5, prepare for blood transfusion, give antibiotics to prevent infection. Surgical procedure 1, wing point approach (1) Craniotomy: The lobes are more exposed than the aforementioned pterional approach, and the sacral leaves are more exposed. The advantages of this approach are: 1 less traction on the temporal lobe than the underarm approach; 2 can see the basilar artery bifurcation, bilateral posterior cerebral artery and perforating artery from the front; 3 oculomotor nerves and trochlear nerve damage are less; 4 can treat aneurysms located on the anterior circulation at the same time. (2) Exposure of the aneurysm: separate the lateral cerebral lobes, separate the frontal and temporal lobes to the sides, open the brain pool, and determine the way to reach the aneurysm according to the anatomical relationship between the optic nerve, the internal carotid artery and the cerebellar margin. When the interval between the internal carotid artery and the optic nerve is at least 5 mm wide, it can pass between the optic nerve and the internal carotid artery. Open the Liliequist membrane in this gap. The internal carotid artery is pulled to the outside, and the posterior communicating artery is also pulled outward to the outside, and the aneurysm can be reached by separating it backward. When the internal carotid artery is close to the optic nerve and a gap cannot be created, the aneurysm can be reached through the intracranial artery and the oculomotor space. The internal carotid artery is pulled inward, and the posterior communicating artery is also pulled inward. When the gap between the internal carotid artery and the optic nerve is small, and the internal carotid artery is close to the free edge of the cerebellum, the temporal lobe can be pulled to the outside, and the cerebellar margin can be cut to enlarge the space from the internal carotid artery. The aneurysm is reached on the outside. After separating the Liliequist membrane, it enters the intercerebral space pool, and follows the posterior communicating artery to the posterior cerebral artery, and finds the bifurcation and aneurysm of the basilar artery behind the posterior bed. If the bifurcation is lower than the posterior bed, the aneurysm neck and part of the tumor are blocked. In this case, it is necessary to bite or use a micro-a diamond to grind a part of the posterior bed to reveal the aneurysm neck. If the aneurysm is poorly exposed, the constituent arteries of the cerebral arterial ring can be severed to expand the exposure according to the following conditions. When the posterior communicating artery is dysplastic, the P1 segment of the ipsilateral posterior cerebral artery develops well, and the distal segment of the posterior cerebral artery is mainly supplied by the basilar artery, which can cut off the posterior communicating artery. It is usually cut at the site where the middle artery of the posterior communicating artery is not separated. First clip it with two small silver clips and then cut it off. Thus, the thalamic anterior perforating artery issued by the posterior communicating artery is supplied with blood from the internal carotid artery and the basilar artery system, respectively. (3) Separation of the aneurysm: the tumor neck is separated from the posterior cerebral artery and the perforating artery from the bifurcation. The top of the tumor points to the front and the upper part of the artery is placed behind it, and is separated from the aneurysm by a curved stripper; the top of the tumor points to the rear, the artery is in front of it, affecting the separation of the aneurysm; the neck neck can be used in two stages. Electrocoagulation narrows it, which facilitates clipping and separation from surrounding blood vessels. (4) Clip aneurysm: a tumor clip is inserted between the neck and the posterior cerebral artery. The direction of the tumor clip is from front to back, 1 to 2 mm from the intersection, so as to avoid tearing the neck and P1 during clipping. The junction of the segments (this is likely to occur when there is a change in arteriosclerosis in the neck of the tumor). Be careful not to include the perforating artery in the tumor clip. When there is an important artery or branching at the neck of the neck that is difficult to retract, a looped aneurysm clip can be applied, and the posterior cerebral artery or important branch is placed in the loop, and then the neck is clamped. 2, bungee approach The craniotomy of the bungee approach is the same as the pterional approach, except that the patella resection is more downward and forward. Electrocoagulation cuts off the parietal vein of the sphenoid sinus, and pulls the bungee back and out to reveal the cerebellar incision. The internal carotid artery is pulled to the medial side to reveal the aneurysm. complication 1, brain stem ischemia. The bifurcation of the basilar artery is clipped, and the blood supply from the collateral branch of the carotid artery is insufficient, or the artery is damaged or mis-clamped, which can cause brain stem ischemia and become an important cause of death or disability. 2, oculomotor nerve and trochlear nerve injury. 3, brain damage can cause hemiplegia.