Middle and lower basilar artery aneurysm clipping

The basilar artery middle and lower aneurysms include aneurysms that occur at the origin between the plane of the superior cerebellar artery and the junction of the vertebral-basal artery. The aneurysms here are rare, accounting for only about 1% of all intracranial aneurysms (0.5% to 1.8%), accounting for about 15% of posterior circulation aneurysms. Because the aneurysm is located in the ventral side of the brainstem, the operation is difficult to expose, the operation range is narrow, and many perforating arteries are emitted from the basilar artery. Many cranial nerves hinder the exposure and operation. Therefore, the clamping of the aneurysm is technically more Difficulties, but the risk of surgery is also greater, in the treatment of more should consider intravascular embolization. Treating diseases: aneurysms Indication The basilar artery middle and lower aneurysm clipping is suitable for: 1, aneurysm has a history of bleeding, or accidentally discovered unruptured aneurysm, unsuitable or unwilling to undergo endovascular embolization. 2, a large aneurysm, there are local occupying symptoms. Contraindications 1. Those who are critically ill after aneurysm rupture. 2, poor general condition, can not tolerate the operator. Preoperative preparation 1. Detailed imaging examinations should be performed before surgery, including CTA, MRA, DSA, etc., to understand the size and position of the aneurysm neck and its relationship with adjacent structures, and to observe the drainage of the sigmoid sinus on both sides in order to determine the operation. Whether it can be cut off. 2. Perform a vertebral-basal artery block test to understand the ability of the carotid system to block the distal basilar artery and tolerate temporary blockade after posterior communicating artery filling. 3. Give corticosteroids and prophylactic antibiotics before surgery. 4, the risk of surgery is large, there is the possibility of damage to the cranial nerve, so the patient and family must be explained before surgery, facial paralysis, hearing loss, long-term tracheotomy and dysphagia need nasal feeding diet, in full The operation can be performed after understanding and agreeing. Surgical procedure Treatment of the basilar artery in the middle and lower aneurysms can be: 1 through the transpetrosal approach; 2 far lateral approach. These two approaches can have a variety of joint approaches, the purpose of which is to expand exposure, reduce the traction of the brainstem, and choose according to the specific circumstances of the aneurysm. 1. Through the rock bones There are three types of retrolabyrinthine approach, translabyrinthine approach and transcochlear approach. (1) After the labyrinth approach: the incision starts from 1 cm in front of the upper edge of the zygomatic arch, and is curved upwards and then bypasses the auricle to stop the mastoid tip plane behind the mastoid. The scalp and muscles are turned from the periosteum down to the trailing edge of the outer ear hole, and the mastoid and the outer side of the rock bone are removed by a rapid grinding drill. The occipital and tibia are opened by a milling cutter or a borehole to reveal the sigmoid sinus and Upper sinus. (2) After getting lost: If the incision is as above, it is necessary to further enlarge the three semicircular canals by grinding with a grinding drill, but to preserve the facial nerve canal, this approach will lose hearing, but the front of the brain stem is better. (3) through the cochlear approach: the incision as described above, further enlarge the exposure, grinding the facial nerve canal, cutting the shallow nerve, dissipating the facial nerve and retracting backward, removing the tympanic cavity, the internal auditory canal and the cochlea to reveal the neck The venous ball and the carotid canal are ground, which is better for the slope and the front of the brain stem. (4) Dural incision: The dura mater can be opened after the sigmoid sinus or after the sigmoid sinus. The former only needs to cut the sinus on the rock, while the latter cuts off the sigmoid sinus. Cutting the superior sinus on the rock generally does not cause venous return obstruction, but the exposure to the surgical field is limited. Cutting off the sigmoid sinus can enlarge the exposure, but may cause venous return obstruction. Therefore, it is necessary to determine the sinus flow at the sinus sinus. The venous blood from the ipsilateral Labbé vein, sagittal sinus and sinus sinus can be completely recanalized through the contralateral sigmoid sinus to cut off the sigmoid sinus on the surgical side. To clarify this point, the jugular vein on the surgical side was compressed during cerebral angiography before surgery to observe the size and development of the contralateral sinus. Spetzler temporarily blocked the sigmoid sinus during surgery and used a thick needle to insert the sigmoid sinus near the blockage to measure the venous pressure before and after the blockage. If the venous pressure after blockade is higher than before the blockage < 7mmHg, it means that the sigmoid sinus can be cut off without causing danger. If the pressure rises >10mmHg, the sigmoid sinus can not be cut, only the upper sinus can be cut, and the dura mater can be cut in front of the sigmoid sinus. It is good to cut the dura mater after the sigmoid sinus. (5) Incision of the cerebellum: From the upper sinus or sigmoid sinus to cut the cerebellum to its incision, forming the supratentorial and inferior combined approach, the aneurysm in the middle and lower segment of the basilar artery can be fully revealed. This segment of the aneurysm occurs mostly in the basilar artery from the anterior inferior cerebellum, adjacent to the abduction, face, and auditory nerve, and the neck is carefully separated for clamping. The tumor-bearing artery can be temporarily blocked if necessary, but the time should be as short as possible, or the aneurysm should be separated and clamped under a low-temperature heartbeat. 2, the far lateral approach and its expansion approach The distal lateral approach is an extension of the unilateral suboccipital approach to the lateral side. The lateral extent of the bone resection reaches the posterior margin of the mastoid, and the lower margin of the occipital foramen and the lateral lamina of the atlas are removed downwards. Only the lower slope and the vertebrae can be revealed. - Basilar artery junction, vertebral artery, posterior inferior cerebellar artery and lower brain stem. The enlarged bone resection range is extended upwards and outwards, the bones are removed or lost, and the sigmoid sinus and cerebellum are cut off to expose the basilar artery aneurysm. (1) The position is in the prone position, the patient is fixed in comfort, and the head is fixed with the Mayfield head frame. (2) Do a hockey-stick incision, starting from the mastoid upward along the upper line to the occipital trochanter, descending along the posterior median line to the 5th cervical spine plane, strictly in accordance with the white line of the midline Up to the occipital bone and spinous processes. The cervical fascia and the cervical muscle were severed 1 cm below the attachment edge for suturing at the end of the procedure. The muscles were pushed down from the subperiosteum of the occipital bone to reveal the half-sided lamina of the first and second cervical vertebrae. Use a fish-hook to pull the skin flap down and out. (3) The scope of bone resection includes a half of the lamina of the atlas, the inner side just over the midpoint, and the lateral side reaches the vertebral artery sulcus. If it is necessary to extend downward, the half-sided lamina of the second cervical vertebra can also be removed. If the ends of the lamina are cut with a saw, they can be reset and screwed after surgery. The occipital bone resection ranged up to the lower edge of the transverse sinus, medial to the midline, lateral to the sigmoid sinus, and the lower edge of the occipital foramen was cut under the occipital foramen. (4) The dura mater was cut in an arc and fixed with a silk suture on the lateral tissue. This simple distal approach only reveals the vertebral artery and its confluence. If the middle and lower segments of the basilar artery are to be revealed, it is necessary to combine the superior and inferior cerebral ventricles and different ranges of the trans-spine approach. 3, far lateral joint approach There are two types of far-lateral combined approach: one is the supratentorial and the lower combined approach, and the other is based on the former combined approach plus the trans-slim approach, the so-called joint-joint approach ( Combined-combined approach). The incision of the superior and inferior approach is from the upper ear of the zygomatic arch, bypassing the humerus, parietal bone and occipital bone to the plane of the spinous process of the third cervical vertebra. The scope of bone resection is also enlarged upwards, and part of the rock bone is removed. After measuring the drainage of the sigmoid sinus, the sigmoid sinus and the cerebellum are cut off, and the vertebral and basilar arteries can be fully revealed. This approach facilitates the treatment of giant aneurysms of the basilar artery. complication 1, brain stem ischemia. 2, cranial nerve injury. 3, cerebrospinal fluid leakage.

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