Clinical Study And Microsurgical Anatomy Of The Posterior Cerebral Artery

Object i ves:To study the microsurgery of the posterior cerebral artery and the main branches; make clear the neighbouring structures and their blood-supply,and therefore provide anatomical data for relevant clinical operations in this area such as the aneurysm clipping operation and the intervention operation. This article aims to explore different parts of the posterior cerebral artery, different forms of aneurysms involved the choice of treatment and clinical efficacy.Methods:Ten(20sides) adult cadaveric specimens which were perfused with colored silicone were studied by using pretemporal approach、subtemporal approach and occipital transtentorial approach.And we observed the relationship among the important neurovascular structures, and described the exposure scope of the posterior cerebral artery and compared the difference of the three approaches. To retrospectively evaluate the data of the6patients which were treated between2006.01to2012.06., which included3males and3females; in the P1-P2junction1cases, in the P2segment3cases, in the P3segment2cases.4cases are saccular aneurysms,1case is dissecting aneurysm,1case is lobulated aneurysm; Hunt&Hess grade0in1case,5cases of grade I,1case of grade IV..3cases were treated with coil embolization.3cases were treated with parent artery occlution.. Clinics or telephone review after3months, after6months all patients are evaluated by angiography.Results1. There are a lot of perforator arterys arising from the posterior cerebral artery, especially the P1segment and the P2segment.2. Pretemporal approach can use three corridors to the posterior cerebral artery,between the optic nerve and the carotid artery, between the carotid artery and the oculomotor nerve,or between the oculomotor nerve and the tentorial incisura.The exposure angle was enlarged after removing the posterior clionoid process,3. Subtemporal approach permits observation from the lateral direction to the posterior cerebral artery. Through the visual fields,we can expose the anterior choroidal artery、the oculomotor nerve and the P2segment and the P3segment of the posterior cerebral segment. 4. Occipital transtentorial approach permits observation from the posterior direction to the posterior cerebral artery.Through this approach we can expose the posterior of the anbient cistern、the quadrigeminal cistern and the posterior medial part of the hippocampus and the P3segment and the P2P segment of the posterior cerebral artery.5. Of those6patients,3patients were treated with endovascular coiling,3patients were treated with parent artery occlusion. Of those who were treated with parent artery occlusion,1patient had a postoperative visual field defect,the others all had no serious complications. During the follow-up of3-56months, all patients had no recurrence of symptoms, patients have no bleeding in5patients with subarachnoid hemorrhage.3patients which were treated with endovascular coiling underwent DSA follow-up, no recanalization.3cases of patients with occlusion of the parent artery, aneurysm disappeared.2patients can find obvious compensatory circulation reverse filling posterior cerebral artery or supply area,1patients were found no significant compensatory increase in blood supply. The long-term prognosis of6patients with GOS score, GOS score was5points. After operation,1patients left visual field defect failed to restore.Conclus ions1. The posterior cerebral and its branches have close relationship with important neural structures. being familiar with the microsurgical anatomy of the posterior cerebral artery will improve the safety and reliability of operation in this region.2. Pretemporal approach combines the pterional approach and subtemporal approach together. We can see clearly the contralateral posterior cerebral artery.It is the first choice when dealing with the aneurysms of the P1segment and the P2segment.3.Subtemporal approach can expose clearly the thalamic perforating arterys and the peduncular perforating arterys.It is a better choice when dealing with the aneurysms of the P2segment and the P3segment.4. Occipital transtentorial approach can expose clearly the posterior part of the ambient cistern, quadrigeminal cistern, the contralateral part of the hippocampus and the P2p segment and the P3segment.When we deal with the aneurysms of the P2 segment in a higher postion of the posterior ambient cistern and the P3segment aneurysms, and more distal aneurysms, it is a good choice.5. The incidence of posterior cerebral artery aneurysms is low,which often occurs in the P2segment and the most common clinical symptom is subarachnoid hemorrhage. Interventional therapy has become the preferred means of dealing with the posterior cerebral artery aneurysms. For a narrow neck aneurysm, embolization is a kind of effective treatment method. For wide-necked aneurysms. with stent and coil embolization technique can achieve good effect. For some complex aneurysms.Occlusion of the parent artery is an effective method. The posterior cerebral artery with good collateral circulation, so the occlusion of the parent artery aneurysm is feasible and safe.And pay attention to the prevention and treatment of the complications of interventional therapy.