Study of multiple cerebral aneurysms comprised of both ruptured and unruptured aneurysm--an analysis of incidence rate with respect to site and size

The purpose of this investigation was to study the incidence rate of rupture with respect to the site and size of multiple cerebral aneurysms that include both ruptured and unruptured aneurysms. Site and size were investigated in 58 cases of this type of multiple cerebral aneurysm. All cerebral aneurysms were examined with MR angiography, 3D-CT angiography and digital subtraction angiography, as well as seeing measured using 3D-CT or digital subtraction angiography. As regards the site of the 58 ruptured cerebral aneurysms under study, 18 were internal carotid aneurysms (C2 or C3: 4 cases, IC-PC: 12 cases, IC-ancho.: 1 case, IC terminal: 1 case), 25 were anterior communicating aneurysms, 10 were middle cerebral aneurysms, 4 were anterior cerebral aneurysms and 1 case was a VA-PICA aneurysm. The ruptured internal carotid aneurysms were 4.0-21.0 mm in size, the anterior communicating aneurysms were 1.8-13 mm, the middle cerebral aneurysms were 2.0-21.3 mm, the anterior cerebral aneurysms were 3.2-9.1 mm, and the VA-PICA aneurysm was 4.4 mm. The sites of the 89 unruptured cerebral aneurysms break down as follows: 29 were internal carotid aneurysms (C2 or C3: 4 cases, IC-PC: 10 cases, IC-ancho.: 10 cases, IC terminal: 5 cases), 18 were anterior communicating aneurysms, 34 were middle cerebral aneurysms, and there were 5 cases of posterior circulation aneurysm. In size, the unruptured internal carotid aneurysms were 1.0-18.3 mm, the anterior communicating aneurysms were 1.0-6.5 mm, the middle cerebral aneurysms were 1.0-10.3 mm, the anterior cerebral aneurysms were 1.0-3.3 mm, and the posterior circulation aneurysms were 2.2-17.3 mm. Out of 58 ruptured cerebral aneurysms, 44 were of the largest size category, and 53 (91.4%) were in the largest size category and/or anterior communicating aneurysms. The accumulated incidence rate of rupture of anterior communicating aneurysms rose suddenly upon reaching 2 mm in size, and after reaching 3 mm, these aneurysms accounted for a nearly uniform 55%-60% of the incidence rate of rupture. The accumulated incidence rate of rupture of IC-PC aneurysms rose drastically at 4 mm in size with the data describing a parabolic slope when graphed. IC-PC aneurysms represented a uniform 55% of the incidence rate of rupture after reaching 8 mm in size. The accumulated incidence rate of rupture of middle cerebral aneurysms rose in a gently sloping parabola beginning at 4 mm, and stabilized at 20% upon reaching 10 mm. These results suggest that each site is associated with a characteristic size and rate of aneurismal rupture. Special attention should thus be paid to large and anterior communicating aneurysms when operating on multiple cerebral aneurysms.     

Diagnosis and treatment of vertebral aneurysms

The intracranial vertebral artery and its branches are a common site of aneurysms in the posterior fossa. Ninety-four aneurysms in 86 patients were analyzed for their clinical manifestation, diagnosis, and treatment. There were three distinct varieties of aneurysm in this group: 56 (60%) saccular aneurysms, 26 (28%) dissecting aneurysms, and 12 (13%) atherosclerotic fusiform aneurysms. Of the 26 dissecting aneurysms, 81% bled and 24% of these rebled. None of the atherosclerotic fusiform aneurysms bled. Angiographic differentiation between dissecting aneurysms and atherosclerotic fusiform aneurysms was difficult. The dissecting aneurysms were characterized by a "narrowed segment" proximal and/or distal to a "fusiform dilatation" of the affected artery and by the presence of contrast medium in the intramural false lumen until the late phase. Poor postoperative outcome and the lateral medullary syndrome were seen only in dissecting aneurysms. Small atherosclerotic fusiform aneurysms seemed to be benign lesions that do not require any surgical treatment.     

Size and location of ruptured cerebral aneurysms diagnosed by three dimensional computed tomographic angiography

The purpose of this study is to confirm the correct size and the location of ruptured cerebral aneurysms diagnosed and measured using three dimensional computed tomographic angiography. The size and the location were investigated in 136 ruptured cerebral aneurysms encountered in our hospital during 3 years and 10 months. As regards the location of 136 ruptured cerebral aneurysms, 40 were anterior communicating artery aneurysms, 35 were middle cerebral artery aneurysms, 33 were internal carotid artery aneurysms, 12 were distal anterior cerebral artery aneurysms and 16 were posterior circulatory aneurysms. Twenty-seven aneurysms (19.9%) were smaller than 3.0 mm, and 74 aneurysms (54.4%) were less than 5.0 mm in maximum diameter. The maximum diameter of aneurysms located on the anterior communicating artery was 4.8 mm. On the middle cerebral artery it was 6.7 mm, and on the internal carotid artery it was 7.4 mm. We concluded that the rate of small aneurysmal rupture was comparatively more frequent than is reported. The results led to the speculation that the aneurysmal rupture occurred more often in smaller size, and the rate of occurrence may be also related to the aneurysmal location.     

Why are aneurysms of the posterior inferior cerebellar artery so unique? Clinical experience and review of the literature.

BACKGROUND: Aneurysms of the posterior inferior cerebellar artery (PICA) are rare lesions. The anatomical behaviour of the artery itself is complex and characterised by a multitude of variations. The same holds true for the aneurysms discovered there. Dissecting aneurysms can be found from the PICA origin to the distal artery berry. They have a wider range of clinical and radiographical presentations and their surgical treatment requires more than one standard approach. METHODS: We encountered 14 patients with PICA aneurysms within two surgical series of a total of 1345 cerebral aneurysm patients (1 %). In this patient group of the last 27 years only 3 of the 14 were distal aneurysms ("true" PICA aneurysms) RESULTS: The 14 patients harboured 15 aneurysms (9 right-sided and 6 left-sided). The female/male ratio of the patients was 9/5, the mean age 52.7 years. 13 of them had sustained an SAH. 7/14 patients were hypertensive, in 10 patients at least one of putative cerebrovascular risk factors was found. From the 15 aneurysms treated, 11 were typical berry aneurysms, 4 dissecting aneurysms. The aneurysms ranged in size from 5 to 20 mm (mean 9.1). 11 aneurysms were located within the anterior medullary segment, 1 in the tonsillomedullary and 2 in the telovelomedullary segments. All patients were surgically treated, 10 in a semi-sitting position via a suboccipital craniotomy, 4 in the prone position. 13 aneurysms were clipped, two were treated differently. Two patients died due to their bad preoperative clinical status. CONCLUSIONS: The clinical, radiographical and surgical approaches to PICA aneurysms still represent a challenge.     

Surgical treatment of unruptured intracranial aneurysms

Summary The author has reviewed a series of 19 patients with unruptured aneurysms treated surgically during a 5-year period from 1976 to 1981. Unruptured aneurysms found in patients with multiple aneurysms and subarachnoid haemorrhage due to ruptured aneurysms are not included in this series. Literature on this subject is reviewed. There was no mortality and results were excellent in 7 patients with asymptomatic aneurysms. In 12 patient with symptomatic aneurysms there was no mortality and results were good to excellent in 9 patients. In 2 the results were unsatisfactory.The series included aneurysms varying in size from 5 mm to over 2.5 cm (giant aneurysm). Controversial aspects of surgery of unruptured intracranial aneurysms are discussed. The authors recommend surgical treatment of unruptured intracranial aneurysms regardless of size until such time when more definitive information is available about the natural history of these lesions.     

The three-dimensional CT angiography findings of ruptured aneurysms hardly detectable by repeated cerebral angiography

We reported three cases of cerebral aneurysms hardly detectable by cerebral angiography, but easily detected by three-dimensional CT angiography (3D-CTA). These cases were ruptured aneurysms with subarachnoid hemorrhage. After detection of subarachnoid hemorrhage on CT scan, cerebral angiography was performed at first, but aneurysms were not detected. Subsequently 3D-CTA was carried out, and aneurysms were detected. In all cases, cerebral angiography was repeated, after the aneurysms had been found by 3D-CTA. This time aneurysms were all detected by cerebral angiography, but each case needed photographs from special direction. The aneurysms were small by usual cerebral angiography and they were almost invisible behind the artery near which they existed. 3D-CTA was very useful for detection of small aneurysms, but small perforating arteries around the aneurysms were invisible by 3D-CTA. To find these perforating arteries, cerebral angiography was needed.     

Double aneurysms at distal basilar artery: report of nine cases

OBJECTIVE: Double aneurysms at the basilar bifurcation and the basilar artery-superior cerebellar artery (BA-SCA) junction have not been well investigated previously. We analyzed nine patients with double basilar aneurysms to evaluate their radiological characteristics and suitable treatment. METHODS: Between 1978 and 1999, the incidence of double aneurysms was 5.3% in our 169 consecutive surgical cases of distal BA aneurysms. Seven (77.8%) of the nine patients with double aneurysms had associated aneurysms in the anterior circulation. Open surgery was performed in eight patients and coil embolization in one. The patients' radiological findings, choice of treatment, and surgical results were analyzed retrospectively. RESULTS: The size of the basilar bifurcation aneurysms ranged from 2 to 8 mm (mean, 4.4+/-2.0 mm), and the size of the BA-SCA aneurysms ranged from 2 to 12 mm (mean, 5.6+/-3.6 mm). Diagnosis of double basilar aneurysms was difficult when the basilar trunk had twisted or when size differences between the two aneurysms were apparent. The angle between the posterior cerebral artery and SCA appeared to be wider on the same side as the BA-SCA aneurysms (101+/-42 degrees) than on the opposite side (26+/-24 degrees). The P1 segment of the posterior cerebral artery originated in an upright direction from the basilar bifurcation between the two basilar aneurysms in seven patients. The pterional approach was used in eight patients; 14 basilar aneurysms were successfully clipped and 2 were wrapped. Nonstraight clips with short blades were used frequently. Coil embolization of double aneurysms was required twice in one patient because the initial angiogram was misinterpreted as a single aneurysm and its bleb. CONCLUSION: Measurement of the posterior cerebral artery-SCA angle is a simple method to estimate the presence of BA-SCA aneurysms and to differentiate double aneurysms from a bilocular aneurysm at the basilar bifurcation. The pterional approach is suitable for clipping double basilar aneurysms because anterior circulation aneurysms often coexist, and the upstanding P1 segment is an obstacle in the subtemporal approach to the basilar bifurcation aneurysm. Nonstraight clips with short blades are convenient to avoid conflicting clips in the narrow surgical space.     

Direct surgical management of aneurysms in the cavernous sinus: a report of 5 cases

Five patients with aneurysms in the cavernous sinus were treated by direct surgical approach. Two small aneurysms were located in the C3 segment, one small aneurysm was on the primitive trigeminal artery (PTA), and the last two aneurysms were giant ones. The three small aneurysms were discovered incidentally by angiography and the two giant aneurysms presented oculomotor palsy. After ordinary fronto-temporal craniotomy, the two C3 aneurysms were treated through an intradural approach, and the PTA aneurysm and the two giant aneurysms were treated through combined epi- and subdural approach. The three small aneurysms were clipped and the two giant aneurysms were trapped with the reconstruction of ICA by saphenous veins. In all cases the aneurysms were excluded postoperatively, but in one giant-aneurysm case (Case 5) the bypass was occluded postoperatively, but the patient had no permanent neurological deficit. The four patients developed third nerve palsy and one developed fourth nerve palsy which resolved within 3 to 6 months. In one C3-aneurysm case (case i) the patient had loss of vision due to much packing in the medial side of the ICA. All patients were discharged and returned to their usual life. Three cases (case 2, 4, 6) are presented here and the problems of direct surgical management of aneurysms in the cavernous sinus are discussed with the related literature.     

Aneurysms at nonbranching sites in the surpaclinoid portion of the internal carotid artery: internal carotid artery trunk aneurysms

OBJECTIVE: Aneurysms at nonbranching sites in the supraclinoid internal carotid artery (ICA), known as blood blister-like aneurysms or ICA anterior or dorsal wall aneurysms, are not well understood. To clarify this clinical entity, 7408 patients with subarachnoid hemorrhage who were treated during a 5-year period were analyzed. METHODS: Forty-eight patients had aneurysms that were intraoperatively confirmed to be located at a nonbranching site in the supraclinoid portion of the ICA. Neuroradiological and clinicopathological features and outcomes were studied. RESULTS: The aneurysms were divided into the "blister type," with a blood blister-like configuration and fragile walls, and the "saccular type," with a saccular configuration and a relatively firm neck, like ordinary berry aneurysms. The most frequent origin was the anteromedial wall for both types. ICA dissection was associated only with the blister type, and hypertension was more frequent with the blister type (P = 0.0978). The preoperative conditions of the patients were the same, but the outcomes for patients with blister-type aneurysms were worse, because of frequent intra- and postoperative aneurysmal bleeding. Saccular-type aneurysms were safely clipped. Treatment of blister-type aneurysms by clipping on wrapping material achieved good results, but ICA trapping (P = 0.0952), clipping (P = 0.0146), and wrapping (P = 0.0110) were associated with much worse results. CONCLUSION: Blister-type and saccular-type aneurysms have different shapes and wall characteristics. The saccular type can be treated by clipping, whereas the blister type requires clipping on wrapping material. ICA trunk aneurysms may be a better designation to express the diversity of these aneurysms, rather than ICA blood blister-like or anterior or dorsal wall aneurysms.     

动脉瘤模型栓塞前后血流动力学对比研究

目的 评价动脉瘤模型行腔内微弹簧圈栓塞前后血流动力学的改变，用以判断疗效。方法 运用改进的显微外科技术建立犬颈总动脉（CCA）动脉瘤模型22个，其中侧壁型12个，分叉部4个，末端型6个。术后7～14d行彩色多普勒超声、经颅多普勒（TCD）、数字减影动脉血管造影（IADSA）及经微导管动脉瘤内测压，然后以微弹簧圈紧密填塞动脉瘤腔，栓塞后重复进行上述检查，比较栓塞前后血流动力学变化。结果 所建模型均获成功。实验证实，动脉瘤微弹簧圈栓塞前后其血流动力学参数的差异有统计学意义（P〈0．01）。结论 实验所建动物模型是研究动脉瘤血管内栓塞治疗的理想方法；动脉瘤微弹簧圈栓塞后，能减低、改变或消除载瘤动脉及动脉瘤内异常血流动力学状态，终止动脉瘤行为，防止动脉瘤扩大和破裂。     

Twenty-six cases regarding the proximal anterior cerebral artery

The authors report twenty-six aneurysms of the proximal anterior cerebral artery (A1 segment). Fourteen cases were male and twelve cases were female. Saccular aneurysms were twenty-four and fusiform aneurysms were two. The incidence of the A1 aneurysms was 0.76%. Clinicopathologically, multiplicity of this aneurysm was distinctive, and eleven cases had multiplicity (42.3%). In the seven cases among them, the A1 aneurysms bled (63.6%). These 26 aneurysms were classified into five types according to the mode of the origin of the aneurysm from the A1 segment: (a) fifteen aneurysms originating from the junction of the A1 segment and the small perforating artery, (b) five from the A1 directly, (c) three from the proximal end of the fenestration of the A1, (d) two were fusiform aneurysms, (e) one from the junction of the A1 and the cortical branch. In CT scan of these aneurysms, bleeding extending to the septum pellucidum is very similar to that of the anterior communicating artery aneurysms.     

Natural history of the neck remnant of a cerebral aneurysm treated with the Guglielmi detachable coil system

OBJECT: The long-term durability of Guglielmi detachable coil (GDC) embolization of cerebral aneurysms is still unknown. The purpose of this study was to evaluate the anatomical evolution of neck remnants in aneurysms treated with GDCs. METHODS: Of 455 aneurysms treated with GDCs from 1990 to 1998 at the University of California at Los Angeles Medical Center, 178 aneurysms (39%) had residual necks postembolization. Long-term follow-up angiograms were obtained in 73 of these aneurysms in 71 patients. The mean duration of angiographic follow up was 17.3 months. Twenty-four of the aneurysms were small with small necks, 24 were small with wide necks, 15 were large, and 10 were giant aneurysms. In small aneurysms with small necks, postembolization angiography revealed 12 aneurysms (50%) with progressive thrombosis, eight (33%) unchanged, and four (17%) with recanalization. In small aneurysms with wide necks, six (25%) had progressive thrombosis, eight (33%) remained unchanged, and 10 (42%) had recanalization. In large aneurysms, two (13%) were unchanged and 13 (87%) had recanalization. Of the giant aneurysms only one (10%) remained unchanged and nine (90%) had recanalization. Overall, 18 aneurysms (25%) exhibited progressive thrombosis, 19 (26%) remained unchanged, and 36 (49%) displayed recanalization on follow-up angiography. During the last 2 years of the study, the recanalization rate decreased and a higher rate of progressive thrombosis was noted in aneurysms with small necks. These positive changes are related to important new technical developments. CONCLUSIONS: Treatment with GDCs appears to be effective and the results permanent in most small aneurysms with small necks. However, there are important technical limitations in the current GDC technology that prevent recanalization in wide-necked or large or giant aneurysms.     

Multiple intracranial aneurysms in elderly patients

Summary The clinical characteristics of elderly patients with multiple intracranial aneurysms were studied. A total of 481 patients, in whom the exact location of their ruptured aneurysms could be confirmed, were classified into two age groups, that is, those aged 59 years or younger (group 1: 247 cases, 51%) and those aged 60 years or older (group 2: 234 cases, 49%). The incidences of multiple aneurysms were 30% for group 1 and 27% for group 2. This difference is statistically not significant. The rate of multiple aneurysms was less frequent in males than in females in group 2, whereas no difference could be found in group 1. The age distribution of patients with multiple aneurysms was basically similar to that of patients with single aneurysms. While the highest rupture rate was observed in the anterior communicating artery aneurysms of both groups, this tendency was more prominent in group 2(79%) than in group 1 (59%). The rupture rates for other sites in group 2 were 50% for distal anterior cerebral artery aneurysms, 40% for internal carotid artery aneurysms and 28% for middle cerebral artery aneurysms. The pattern of surgical outcome showed no major differences between multiple and single aneurysms in either group 1 or 2. However, group 1 had better surgical results than group 2.Even though the surgical outcome for multiple aneurysms in elderly patients was satisfactory, awareness of the probability of rupture at each site is helpful, especially when it is necessary to decide whether unruptured aneurysms should be operated on or not.     

不同内径腹主动脉瘤腔内血流状况分析

目的　观察不同内径腹主动脉瘤腔内血流情况。方法　应用二维彩色多普勒超声观察不同内径和形状腹主动脉瘤患者 (2 0例 )和通过牛颈外静脉移植法 (3例 )及补片法 (3例 )制作不同内径和形状的腹主动脉瘤模型的动脉瘤腔内血流。结果　在人体中 ,动脉瘤内径≤ 3 .0cm有 5例 ,其中 4例为层流 ,动脉瘤形态为梭形。动脉瘤内径 >3 .0cm有 15例 ,其中 14例出现湍流。 3例牛颈静脉移植法建立的模型 ,当内径≤ 1.5cm时 ,血流表现为层流 ,动脉瘤形态为梭形。内径 >1.5cm时 ,动脉瘤腔内出现湍流和逆流。 3例牛颈静脉补片法建立的模型 ,在动脉瘤腔内近凸起部位出现湍流和逆流。结论　随着动脉瘤内径的增大和形状的改变 ,瘤腔内的血流更为复杂 ,可能会对动脉瘤的生长、破裂及血栓形成产生进一步的影响。     

Surgical outcome for multiple intracranial aneurysms

Summary The surgical outcome of 221 cases with multiple intracranial aneurysms operated upon during the years 1988 to 1994 were reviewed. The patients were classified into three groups according to the locations of the aneurysms; group 1: multiple aneurysms located unilaterally in the anterior circulation only (147 cases); group 2: multiple aneurysms located bilaterally in the anterior circulation only (44 cases) and group 3: multiple aneurysms located in both anterior and posterior circulation or in the posterior circulation alone (30 cases). In 132 cases of group 1 (89.8%) all aneurysms were treated in one-stage operations. Twenty-eight patients from group 2 (63.6%) received partial treatment, where only the ruptured or the symptomatic aneurysms were treated. In 12 other cases from group 2 (27.3%) all multiple aneurysms were treated in two-stage operations. In group 3 patients, one-stage operations were performed in 18 cases (60%), while 9 patients (30%) received partial treatment only. Of the 221 multiple aneurysm cases, 162 (73.3%) presented with manifestations of subarachnoid haemorrhage (SAH). The remaining 59 multiple aneurysms cases (26.7%) presented with manifestations other than SAH (unruptured aneurysms). In the postoperative follow-up, of the 221 multiple aneurysms cases, 113 (51.1%) were free of neurological deficit (excellent), 48 cases (21.7%) were capable of leading an independent life (good), 32 cases (14.5%) were not independent and needed to be assisted (fair), and 28 patients (12.7%) died. These results were comparable to the results of patients with single aneurysms operated on during the same period.Based on our results, we recommend that whenever possible all multiple aneurysms should be treated in one-stage operations. In unruptured multiple aneurysm cases surgical management is the recommended treatment. In poor grade SAH patients or unruptured multiple aneurysms in old patients, two-stage operations or partial treatment of only the ruptured or the symptomatic aneurysms may be adopted.     

Use of experimental aneurysms to evaluate wrapping materials

Experimental venous pouch aneurysms in rats were wrapped with muscle, bovine collagen, muslin, cotton, or polyvinyl alcohol. The rats were killed 6 or 12 weeks later, and the aneurysms were compared with control aneurysms. Bovine collagen and muscle were reabsorbed and the aneurysms were similar to the control group. Cotton, muslin, and polyvinyl alcohol caused fibrosis around the aneurysm. However, giant aneurysms were found in the muslin and polyvinyl alcohol group. Cotton appears to be the most suitable material for wrapping aneurysms. The experimental venous pouch aneurysm model in rats can be used to evaluate wrapping materials.     

Endovascular treatment of basilar artery trunk aneurysms with Guglielmi detachable coils: clinical experience with 41 aneurysms in 39 patients

OBJECT: The authors present a retrospective analysis of their clinical experience in the endovascular treatment of basilar artery (BA) trunk aneurysms with Guglielmi detachable coils (GDCs). METHODS: Between April 1990 and June 1999,41 BA trunk aneurysms were treated in 39 patients by inserting GDCs. Twenty-seven patients presented with subarachnoid hemorrhage, six had intracranial mass effect, and in six patients the aneurysms were found incidentally. Eighteen lesions were BA trunk aneurysms, 13 were BA-superior cerebellar artery aneurysms, four were BA-anterior inferior cerebellar artery aneurysms, and six were vertebrobasilar junction aneurysms. Thirty-five patients (89.7%) had excellent or good clinical outcomes; procedural morbidity and mortality rates were 2.6% each. Thirty-six aneurysms were selectively occluded while preserving the parent artery, and in five cases the parent artery was occluded along with the aneurysm. Immediate angiographic studies revealed complete or nearly complete occlusion in 35 aneurysms (85.4%). Follow-up angiograms were obtained in 29 patients with 31 aneurysms: the mean follow-up period was 17 months. No recanalization was observed in the eight completely occluded aneurysms. In 19 lesions with small neck remnants, seven (36.8%) had further thrombosis, three (15.8%) remained anatomically unchanged, and nine (47.3%) had recanalization caused by coil compaction. In one patient (2.6%) the aneurysm rebled 8 years after the initial embolization. CONCLUSIONS: In this clinical series the authors show that the GDC placement procedure is valuable in the therapeutic management of BA trunk aneurysms. The endovascular catheterization of these lesions tends to be relatively simple, in contrast with more complex neurosurgical approaches. Endosaccular obliteration of these aneurysms also decreases the possibility of unwanted occlusion of perforating arteries to the brainstem.     

颅内后循环动脉瘤的血管内介入治疗

目的总结颅内后循环动脉瘤的特点,探讨其血管内介入治疗的临床疗效。方法回顾性分析40例行血管内介入治疗的颅内后循环动脉瘤患者的临床和影像学资料、介入治疗过程,观察期效果及术后随访结果。结果 40例患者共发现42个后循环动脉瘤,均完成血管内介入治疗,其中8个行单纯弹簧圈栓塞,28个行支架辅助栓塞,1个行Onyx胶栓塞,5个动脉瘤及载瘤动脉同时闭塞。术后即刻DSA造影显示动脉瘤完全栓塞30个,近全栓塞6个,部分栓塞6个。术后6个月随访DSA造影显示动脉瘤完全栓塞36个,近全栓塞4个,部分栓塞1个。患者出院时行改良Rankin量表(mRS)评分,0分35例,1分3例,2分1例,1例死亡为6分;出院后3~6个月随访mRS评分0分38例,1分1例,无动脉瘤复发及新发神经功能障碍病例。结论颅内后循环动脉瘤具有特殊的临床与影像学表现,且复杂动脉瘤较为常见,对于颅内后循环动脉瘤,血管内介入治疗是一种安全有效的治疗方法。     

Unruptured intracranial aneurysms in elderly patients.

A total of 556 patients with 769 intracranial aneurysms, of which 256 were unruptured and 513 were ruptured, were included in the present study. The patients were divided into three age groups: those aged 59 years or younger, those aged 60 to 69 years, and those aged 70 years or older. Small aneurysms of 4 mm or less in diameter were more common in the series of unruptured aneurysms than in the ruptured aneurysms. The rupture rate in anterior communicating artery aneurysms was the highest, and it increased with age. A follow-up study was performed on 47 patients with 55 unruptured aneurysms, and only one giant basilar artery aneurysm ruptured during the average follow-up period of 5.2 years. Direct operation was performed on 52 patients with unruptured aneurysms. While the surgical mortality rate was 0%, the morbidity rate was 6% (three of 52 cases), which was not directly related to the patients' age. When considering surgery for unruptured aneurysms, rupture rate of aneurysms at each site is one of the most important factors, especially in elderly patients.     

Angiographic characteristics of ruptured paraclinoid aneurysms: risk factors for rupture

Background

The diagnosis and treatment of unruptured paraclinoid aneurysms has been increasing with the recent advent of diagnostic tools and less invasive endovascular therapeutic options. Considering the low incidence of rupture, investigation of the characteristics of ruptured paraclinoid aneurysm is important to predict rupture risk of the paraclinoid aneurysms. The objective of this study is to evaluate probable factors for rupture by analyzing the characteristics of ruptured paraclinoid aneurysms.

Methods

A total of 2,276 aneurysms (1,419 ruptured and 857 unruptured) were diagnosed and treated endovascularly or microsurgically between 2001 and 2011. Among them, 265 were paraclinoid aneurysms, of which 37 were ruptured. Removing 12 blister-like aneurysms, 25 ruptured and 228 unruptured saccular aneurysms were included and the medical records and radiological images were retrospectively analyzed.

Results

Of 25 aneurysms, 16 (64.0 %) were located in the superior direction. Five were inferior located lesions (20 %) and four were medially located lesions (16.0 %). Laterally located lesions were not found. The mean size of aneurysms was 9.4?±?5.6 mm. Ten aneurysms (40.0 %) were ≥?10 mm in size. Thirteen aneurysms (52.0 %) were lobulated. The superiorly located aneurysms were larger than the other aneurysms (10.3?±?5.8 mm vs. 7.7?±?4.9 mm) and more frequently lobulated (ten of 16 vs. three of nine). In a comparative analysis, the ruptured aneurysms were located more in the superior direction compared with unruptured aneurysms (64 vs. 23.2 %, p?<?0.0001). Large aneurysms (36.0 vs. 7.9 %, p?<?0.0001), longer fundus diameter (mean 9.4?±?5.6 vs. 4.8?±?3.3 mm, p?=?0.001), dome-to-neck ratio (mean 1.8?±?0.9 vs. 1.2?±?0.5, p?<?0.0001), and lobulated shape aneurysms were more likely to be ruptured aneurysms (13 of 25 ruptured aneurysms, 52.0 %, p?=?0.001).

Conclusions

Rupture risk of the paraclinoid aneurysm is very low. However, superiorly located paraclinoid aneurysms appear more likely to rupture than other locations. Angiographically, more conservative indication for the treatment of paraclinoid aneurysm should be recommended except for superior located lesions.