Surgical treatment of distal anterior cerebral artery aneurysms (author's transl)

Forty-five patients with aneurysms of the anterior cerebral artery distal to the anterior communicating artery were operated on by a direct approach method in the years 1960-1973. The incidence of aneurysms in this location was 4.8% of the total 1,000 aneurysms. It is of upmost importance in the treatment of aneurysms to insure the parent artery for the purpose of temporary occlusion. This makes it easier and safer to approach the aneurysmal neck and to handle possible premature aneurysmal rupture. From this technical standpoint, the aneurysms in this location were classified into two types, ascending and horizontal. Aneurysms of the pericallosal artery between the origin of the anterior communicating artery and the knee of the corpus callosum were designated as the aneurysms of the ascending portion, whereas the aneurysms of the pericallosal artery from the knee of the corpus callosum and beyond were designated as the aneurysms of the horizontal portion. Depending on the location of the aneurysm, craniotomy was performed at one of two different sites. For aneurysms of the ascending portion, bifrontal craniotomy was determined and applied as the safest approach. A small parasagittal craniotomy was determined to be sufficient for aneurysms of the horizontal portion. Although the total operative mortality was 4 of 45 cases (9.0%), no mortalities nor morbidities occurred in the last 12 cases since 1972, when the sites of craniotomies were differenciated.     

Surgical treatment of distal anterior cerebral artery aneurysms with horizontal head position.

OBJECTIVE: In the surgery for a distal anterior cerebral aneurysm which is applied with a vertical head position, the dome of the aneurysm makes it difficult the expose the neck and the proximal artery. This study was performed to evaluate the applicability of the alternative contralateral interhemispheric approach with a horizontal head position for clipping these aneurysms. METHOD: The head of the patient was placed in the horizontal position such that the aneurysm side remained at the top and then tilted 45 degrees superiorly. On the contralateral side, the craniotomy, interhemispheric dissection and clipping were performed in 12 patients with 13 aneurysms. RESULTS: All aneurysms were clipped successfully. Problems in the standard supine position such as the obstruction of the access to the aneurysm neck and the proximal artery by the dome were not encountered. Vasospasm developed in 4 patients and akinetic mutism in 1 patient; postoperative convulsion due to an inadvertent cortical venous injury in one patient resolved with medical treatment. Hydrocephalus developed in 2 patients; one patient needed placement of a ventriculoperitoneal shunt while the other responded to occasional lumbar punctures. Mortality or permanent morbidity did not occur. CONCLUSION: The horizontal head position may be an alternative for circumventing difficulties posed by the location of distal anterior cerebral artery aneurysms.     

Surgical strategy for distal anterior cerebral artery aneurysms: microsurgical anatomy

OBJECT: Most distal anterior cerebral artery (ACA) aneurysms arise at the pericallosal-callosomarginal artery (PerA-CMA) junction, which is usually located in the A3 segment of the ACA around the genu of the corpus callosum. Aneurysms in the PerA-CMA junction are divided into two types according to their location: supracallosal and infracallosal. Infracallosal distal ACA aneurysms are defined as those located in the lower half of the A3 segment, which makes it more difficult to gain proximal control. In this study, the authors examined the microsurgical anatomy of the distal ACA region, focusing especially on the relationship between the PerA and CMA located in the lower half of the A3 (infracallosal) segment, and present a surgical strategy for dealing with distal ACA aneurysms. METHODS: The microsurgical anatomy of the distal ACA region was examined in 22 adult cadaveric cerebral hemispheres after perfusion of the arteries and veins with colored silicone. The relationships of the infracallosal segment of the PerA to the CMA and the A2 segment of the PerA to the frontopolar artery were examined. The distance between the nasion and the site at which a parallel line directed along the long axis of the infracallosal PerA just proximal to the origin of the CMA artery crosses the forehead (which we have named the PC point) was also measured. Surgical approaches to distal ACA aneurysms were examined in stepwise dissections. CONCLUSIONS: The PerA-CMA junctions were located in the supracallosal and infracallosal segments of A3 in 36 and 55% of cases, respectively. In the infracallosal region, it was difficult to identify the proximal PerA and to establish proximal control of the vessel. The infracallosal part of the proximal PerA coursed almost parallel to the frontal cranial base, and the PC point was 42.2 +/- 15.9 mm (mean +/- standard deviation) from the nasion. These findings indicate that there is only a limited space in which to access an infracallosal distal ACA aneurysm below the PC point and establish proximal control by the anterior interhemispheric approach. When the approach is made above the PC point, an anterior callosotomy may be necessary to establish proximal control before final aneurysm dissection and clip placement are completed. The PC point is an important surgical landmark in planning the surgical strategy for infracallosal distal ACA aneurysms.     

Saccular aneurysms of the distal anterior cerebral artery

We report a series of 42 consecutive patients with aneurysms of the distal anterior cerebral artery (ACA). Of these, 36 patients had one aneurysm, 5 had two aneurysms, and one had three aneurysms. Thirty patients had a ruptured distal ACA aneurysm; among these patients, the size of the aneurysm was less than 5 mm in diameter in 20, 6 to 10 mm in 7, and larger than 11 mm in 3. Eighteen patients (42.9%) had multiple aneurysms, and distal ACA aneurysms were responsible for a subarachnoid hemorrhage in 10. Thirty-four patients underwent direct surgery, and 30 of these had excellent outcomes 3 months after surgery. The treatment of patients with distal ACA aneurysms is often technically difficult, because of their broad neck configuration and the coexistence of other aneurysms. Nevertheless, the present study emphasizes that distal ACA aneurysms tend to bleed, irrespective of their size, and that excellent outcomes are obtainable by direct surgery.     

血管内治疗大脑前动脉远端动脉瘤

目的观察血管内治疗大脑前动脉远端(DACA)动脉瘤的效果。方法回顾性分析14例接受血管内治疗的DACA动脉瘤患者(共15个动脉瘤),对10个动脉瘤行单纯弹簧圈栓塞、4个动脉瘤行支架辅助下弹簧圈栓塞,1个以Onyx胶栓塞。之后复查DSA,根据Raymond分级评价即刻疗效。术后6个月复查DSA,以改良Rankin量表(mRS)评估预后,mRS评分0~2分为结局良好。结果术后即刻12个动脉瘤Ⅰ级栓塞,3个Ⅱ级栓塞。术中、术后均未发生缺血等并发症。1例术后12 h死于动脉瘤再次破裂出血。术后6个月随访显示1例复发,10例结局良好(mRS评分0~2分),另2例mRS评分分别为3分、4分。结论个体化血管内治疗DACA动脉瘤安全、有效。     

Surgical treatment of middle cerebral artery aneurysms

The authors report their experience with the surgical therapy of middle cerebral artery (MCA) aneurysms in 413 cases, and describe their technique. After the M1 portion of the MCA is identified, the Sylvian fissure is opened. During the administration of 20% mannitol, temporary occluding clips are applied to the feeding and draining vessels of the aneurysm. The aneurysm is freed from all surrounding tissue, and the aneurysm neck is treated by ligation, clipping, or wrapping. Analysis of surgical results in 91 cases operated on after the surgical approach had become standardized indicates that more than 94% of patients have returned to useful social lives by the time of follow-up evaluation. Twenty-four percent of these patients were operated on within 48 hours after subarachnoid hemorrhage.     

大脑前动脉近端动脉瘤的显微外科治疗

目的探讨大脑前动脉近端动脉瘤(A1动脉瘤)的临床特征及外科手术技巧。方法1995年6月～2003年12月间共治疗颅内动脉瘤患者362例,其中A1动脉瘤占2．2％(8例),对A1动脉瘤患者的临床资料进行回顾性分析。结果所有动脉瘤均位于A1穿动脉的起始部,起源于内侧远端纹状体动脉的3例,内侧近端纹状体动脉的5例。术中发现后方指向的6例,下方指向的2例。8个动脉瘤均为囊性动脉瘤,其中6例为小动脉瘤,平均直径6．9mm。全组动脉瘤经手术夹闭,患者预后优7例,良1例。结论手术治疗A1动脉瘤保护A1穿动脉和选用合适的瘤夹是预防缺血性并发症的关键。     

Distal anterior cerebral artery mirror aneurysms and middle cerebral artery aneurysms

A 52-year-old woman presented with bilateral distal anterior cerebral artery (ACA) mirror aneurysms, in addition to two right middle cerebral artery (MCA) aneurysms. The left distal ACA and right MCA aneurysms were clipped through right interhemispheric and right pterional craniotomies. The right distal ACA aneurysm was thrombosed. Distal ACA aneurysms tend to be multiple, but mirror aneurysms are rare, especially in the absence of congenital vascular anomaly. Single stage unilateral craniotomy is recommended for surgical treatment.     

Saccular aneurysms of the distal anterior cerebral artery and its branches.

We report a series of 84 consecutive patients (41 women) with 92 distal anterior cerebral artery aneurysms (DACAA). All aneurysms were saccular. Four different locations of DACAAs were found: proximal, 5 aneurysms; frontobasal, 8; genu corporis callosi, 72; and distal, 7. Sixty-five patients presented with subarachnoid hemorrhage (SAH), the rest were incidental findings in patients with multiple aneurysms. Forty-five patients had single DACAAs. Multiple aneurysms (a total of 117) were found in 39 patients (46.4%), and DACAAs were responsible for SAH in 20 patients. Of the 65 patients with SAH, 54 underwent mainly early direct surgery, and 46 (85%) of these had good outcomes 1 year after surgery. Three patients remained severely disabled, and five patients (9%) died. All of the poor surgical results were obtained in patients with severe preoperative deficits. Exact measurements of DACAA sizes and necks were smaller than those of cerebral aneurysms in other locations. Aside from localization, microsurgery of these aneurysms presented no special difficulties, as compared with surgery of aneurysms in other locations.     

Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals. Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n?=?5) followed by the postmeatal (n?=?3) and premeatal segment (n?=?1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery. We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3?months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75?%). We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.     

Aneurysm of distal anterior cerebral artery associated with azygos anterior cerebral artery

Summary An aneurysm arising from the distal anterior cerebral artery distal to the bifurcation of the azygos anterior cerebral artery is reported. A review of the literature emphasizes the rarity of this lesion.     

大脑中动脉巨大型动脉瘤的手术治疗

目的 探讨大脑中动脉巨大型动脉瘤的手术治疗方法.方法 回顾性分析2001年1月至2008年3月17例颅内大脑中动脉巨大型动脉瘤患者的手术方法和疗效.术前采用CT、CTA、MR、MRA、DSA及三维DSA检查,以了解动脉瘤的部位、大小,形状以及侧支代偿情况,制定个体化治疗方案.在手术入路上多采用改良翼点入路,其中行动脉瘤瘤颈直接或塑形夹闭者4例,动脉瘤孤立或孤立后切除4例,动脉瘤切除或孤立后血管重建7例,动脉瘤包裹2例.结果 CT和MRI能清楚地显示动脉瘤的形状、大小.DSA及三维DSA能显示瘤颈以及与附近血管和骨质的关系.根据格拉斯骨预后评分表评分,出院时恢复优良者12例,中度病残4例,重度病残1例,无死亡病例.结论 术前有必要进行详细的影像学检查,有助于术者规划手术方法,制定个体化治疗方案,采用不同术式取得良好预后.载瘤动脉暂时性阻断、动脉瘤切开血栓清除均有助于瘤颈夹闭.血管重建技术为大脑中动脉巨大型动脉瘤的手术治疗开辟了新途径,明显改善了手术效果.     

Basal interhemispheric approach for distal anterior cerebral aneurysms

PURPOSE: To investigate retrospectively the usefulness of basal interhemispheric approach for neck clipping of aneurysms located on genu or infracallosal portion of anterior cerebral artery. CLINICAL MATERIALS AND METHODS: Seventeen aneurysms in 17 patietns treated by clipping with basal inter-hemispheric approach in our department for past 8 years were reviewed. Of them, 12 were ruptured aneurysm and 5 were unruptured one. The distance between frontal base and most frontally located bridging vein and the shortest distance from cranium to aneurysm were measured from angiograms of lateral view, and the point on cranium of the shortest distance was identified in each cases. Bridging vein damage suffered during surgical approach and the duration of brain retractor use were examined from operative videotapes. The clinical outcome was rated at discharge by Modified Rankin Scale. RESULTS: The distance between frontal base and most frontally located bridging vein was ranged as 15-69 mm (mean, 32 mm). The shortest distance between cranium and aneurysm in each case was ranged as 25-48 mm (mean, 33 mm), and the point on cranium of the shortest distance was these within 20 mm from frontal base in 11 cases. Any damage or cut of bridging vein were not seen in all cases. The duration of brain retractor for unilateral frontal lobe and for bifrontal lobe in recent 14 cases was ranged 0-46 minutes 41 seconds (mean, 8 minutes 55 seconds) and 0-16minutes (mean, 2minutes 24 seconds), respectively. No brain damage caused by operative procedure was detected on postoperative CT scan. All five patients of unruptured one and 8 patients of ruptured one were rated as 0 by Modified Rankin scale, 2 patients of ruptured one as 3 and 5, and 2 patients of ruptured one died. CONCLUSION: The basal interhemispheric approach for neck clipping of aneurysm located on genu or infracallosal portion of anterior cerebral artery would provide wide view of aneurysm and its surrounding structures with minimum retraction of frontal lobe, short distance to the aneurysm, and low risk of bridging vein damage.     

Technical strategy in endovascular treatment of proximal anterior cerebral artery aneurysms

Purpose  

There have been few reports on the endovascular treatment of aneurysms arising from A1 due to their rarity. We report the angiographic results, clinical outcomes, and technical aspects of endovascular treatment for 13 A1 aneurysms in 12 patients.