The Clinical Classification And Microsurgical Clipping Of Posterior Communicating Artery Aneurysms Occurring At Fetal-Type Posterior Cerebral Artery

Objective:To describe the spatial relationship between the PcoA aneurysms occurring at fetal-type PCA and PcoA and were categorized into 7 subtypes.And retrospectively analyze the microsurgical clipping techniques and patients’neurological outcomes.Methods:A total of 192 patients had 212 PcoA aneurysms treated microsurgically were retrospectively analyzed in the 2^nd hospital of Hebei medical university.The patients were categorized into 2 groups with fetal-or normal-type PcoA aneurysms.The basic characteristics between the two groups were compared.Aneurysms were categorized into two groups and the intraoperative consequences of each group were described.The fetal-type PcoA aneurysms were also categorized into several subtypes according to the spatial relationships between the aneurysm and PcoA.The clinical outcomes and intraoperative consequences of each subtypes were also identified.A total of108 patients with fetal-type PcoA aneurysms were followed up 6 weeks and 6months after the microsurgical clipping,and the changes in the prognosis of neurological outcomes were compared.Univariate and multivariate analysis was conducted on the factors affecting the deterioration of prognosis and death.Results:1.The basic characteristics of the two groups of patients include:the average age,elder patients（>70 years of age）,female sex,hypertension,diabetes,Hunt&Hess Grade ofⅣorⅤ,bilateral PcoA aneurysm,preoperative intracranial hematoma,preoperative intraventricular hemorrhage,preoperative oculomotor nerve paralysis,and postoperative intracranial hemorrhage,procedure related low density and new oculomotor nerve paralysis.And the characteristics above showing no statistical significance（P>0.05）.2.The microsurgical clipping techniques and procedure related complications of the fetal-type or normal-type PcoA aneurysms include:the average size of aneurysm,multiple clips utilization,intraoperative rupture,clips readjustment,fenestrated clips utilization,temporary clipping and anterior clinoidectomy.Only the average aneurysm size,the rate of multiple clips utilization,rate of temporary clipping of fetal-type PcoA aneurysms were significantly higher than that of normal-type PcoA aneurysms and showing statistically significant（P>0.05）.3.The fetal-type aneurysms were categorized into 7 subtypes according to the spatial relationship between the PcoA and the aneurysm,in which the type-Ⅴwas a type of complicated anatomy and had higher rate of multiple clips utilization（41.7%）,fenestrated clips utilization（25.0%）,temporary clipping（58.3%）and ischemic complications.4.Patients with fetal-type PcoA aneurysm had a favorable prognosis rate of 66.7%,mortality rate of 4.6%at 6 weeks after surgery,and a favorable prognosis rate of 74.1%and mortality rate of 16.7%at 6 months after surgery.Among them,87%of patients showed improved or unchanged in neurological outcomes at 6 weeks after surgery,with a deterioration rate of 13.0%,while75.9%at 6 months after surgery,with a deterioration rate of 22.2%.5.Univariate regression analysis was performed on 24 patients with neurological deterioration 6 months after surgery.The results showed that patients with high Hunt&Hess grade,preoperative intracranial hematoma,and postoperative ischemic stroke,postoperative cerebral edema and postoperative infection were at higher risk of neurological outcomes deterioration.Multivariate regression analysis showed that high Hunt&Hess grade and postoperative infection were independent risk factors leading to deterioration of neurological outcomes.Conclusion:Posterior communicating aneurysm with fetal-type PCA was a kind of complex anatomical relationship aneurysm.And can be categorized into 7subtypes according to the spatial relationship between the PcoA and the aneurysm.Different microsurgical clipping strategies should be applied on different subtypes.Especially when the aneurysm projecting posteromedial of the operative field or with complicated shapes like huge aneurysms,lobulated,broad neck are at higher risk of occurring complications.Surgeons can evaluate the relationship between the aneurysm and PcoA according to the neuroimaging,so as to provide more information and make plans for various possible conditions during the operation,to complete safe clipping and reduce complications.