Intentional body clipping of wide-necked basilar artery bifurcation aneurysms

OBJECT: Neck clipping or coil embolization cannot always achieve complete neck obstruction in wide-necked basilar artery (BA) bifurcation aneurysms. Clipping of the aneurysm body, leaving a small aneurysm rest, is one clipping method used for this kind of aneurysm to maintain the patency of the posterior cerebral arteries and perforating vessels. However, the long-term efficacy of intentional body clipping has not been well investigated. The authors reviewed their experience with intentional body clipping of wide-necked BA bifurcation aneurysms to determine suitable clipping techniques and the long-term efficacy of the procedure. METHODS: Complete neck occlusion was abandoned and body clipping intentionally performed in 17 patients with BA bifurcation aneurysms; wrapping of the aneurysm rest was made in seven cases. There were 10 ruptured aneurysms (58.8%), and the size of the aneurysm was larger than 10 mm in 11 patients (64.7%). The width between the clip blades and the base of the aneurysm neck was 1 mm in 11 cases, 2 mm in four, and 3 mm in two. Favorable outcome (Glasgow Outcome Scale [GOS] Score 4 or 5) was obtained in 13 cases (76.5%) and unfavorable outcome (GOS Scores 1-3) in four cases (23.5%). Major causes of unfavorable outcome included injury to perforating arteries and major vessel occlusion following surgical manipulation, in addition to the primary damage caused by subarachnoid hemorrhage. Subarachnoid hemorrhage did not occur during a mean follow-up period of 7.4+/-5.6 years (range 0.7-18.1 years) after treatment. CONCLUSIONS: Intentional body clipping of wide-necked BA aneurysms proved to be effective to prevent subarachnoid hemorrhage, although injury to perforating arteries remains problematic. The choice of complete neck clipping or body clipping should be established early during the microsurgical procedure to reduce the risk of injury to perforating vessels.     

Endosaccular occlusion of basilar artery bifurcation aneurysms using electrically detachable coils

Summary Thirteen patients with basilar artery bifurcation aneurysms, treated by electrothrombosis using electrically detachable coils, are presented. Nine of them presented after hemorrhage, two with mass effect, and two were found coincidentally with other ruptured aneurysms. Selection for endovascular therapy was based on the following criteria: 1) poor clinical condition (Hunt and Hess III-V); 2) high surgical risk; 3) age and poor medical condition; 4) morphological features (small necked aneurysms). With endovascular Guglielmi detachable coils aneurysm occlusion ranging from 70–100% was achieved in all cases. All five small necked and two large broad necked aneurysms were totally occluded. Two large aneurysms had a 95% occlusion and two other large aneurysms were 90% occluded. In another patient with a large broad based aneurysm only an 80% occlusion was achieved, because of tortuosity of the vertebrobasilar system. Our last patient, who presented as grade V clinically, was partially treated with a 70% aneurysmal occlusion. The clinical results were excellent in 10 and good in 2. The only poor outcome was seen in the grade V patient. There was no morbidity or mortality related to therapy. The only complication was an asymptomatic dissecting aneurysm at the origin of the vertebral artery. Angiographic follow up time ranged from 6 to 20 months with a mean of 9 months. Four patients were treated too recently to have their angiographic follow up at 6 months. Two patients were lost to follow up. Clinical follow up ranged from 1 to 17 months with a mean of 8.9 months. The analysis of our cases clearly shows that aneurysms, which were densely packed with coils, especially if small necked, were less likely to be reperfused and showed a longlasting stable result. Large broad based aneurysms were more likely to be reopened by blood flow after the first procedure, especially if loosely filled with coils, and needed up to 3 interventions to achieve a satisfying result, whereas later in the series a high percentage rate of occlusion was seen after the first procedure. We consider now also a less than 100% occlusion acceptable, because most of the aneurysms will rupture at the dome, which was occluded in all our cases. We conclude, that this new endovascular method is a viable alternative in the treatment of posterior circulation aneurysms with a high surgical risk, in old patients and those in poor clinical and medical condition.     

Extended lateral transsylvian approach for basilar bifurcation aneurysms

The surgical management of aneurysms of the basilar apex is one of the most challenging areas in neurosurgery. Successful treatment of this subgroup of aneurysms is dependent on the mastery of technical nuances that have been pioneered and advanced over the past 4 decades. Although both the traditional transsylvian and subtemporal approaches have distinct advantages, each is associated with significant limitations. In this article, the senior author shares his insights into a hybrid approach: the extended lateral transsylvian approach. This approach combines the assets of the two traditional approaches while eliminating their liabilities.     

Hemodynamic method to predict whether hunterian ligation of the basilar artery will lead to thrombosis of basilar bifurcation aneurysms

In some cases, basilar artery aneurysms cannot be repaired surgically and the basilar artery is occluded near the neck of the aneurysm to stop flow into the aneurysm. After the operation, the aneurysm can fill only by flow through the posterior communicating arteries (PCoAs). Hemodynamically if the flow were the same in both PCoAs and there were no phase lag in the pressures, there would be no pressure gradient for flow to go across the neck of the aneurysm and therefore the aneurysm would thrombose. We have assumed that the diameter of the artery is roughly proportional to the flow that goes through it chronically. We measured the diameters of the PCoAs in 25 patients who had hunterian ligation of the basilar artery. We also measured the maximal width, height, and depth of the aneurysms on angiograms obtained before and after operation. Eleven aneurysms thrombosed completely and had a diameter ratio of greater than 0.6; 10 aneurysms thrombosed partially and had a diameter ratio of 0.46 approximately 1.0; 4 aneurysms did not change and had a diameter ratio of less than 0.45. The ratio of the sizes of the PCoAs pre- and postoperatively was comparable in most cases, so we believe that it is possible to predict reasonably accurately from this simple measurement whether the aneurysm is likely to thrombose if the basilar artery is ligated.     

Endovascular treatment of basilar artery aneurysms

International experience regarding the treatment of basilar artery aneurysms using the Guglielmi Detachable Coil (GDC) system was reviewed. The four patient series included in this critique were composed of similar numbers of patients who had aneurysms that predominantly involved the basilar artery bifurcation and who presented clinically after a subarachnoid hemorrhage. Consistent results observed between the individual outcome experiences were as follows: (1) complication rates associated with the endovascular treatment of basilar artery aneurysms compared favorably with the historical rates associated with direct surgical clipping; (2) smaller aneurysms in this location could be more safely and completely occluded than their larger counterparts; (3) the endosaccular thrombus produced after GDC placement is a dynamic, rather than permanent, entity; (4) progressive thrombosis, thrombolysis, or compaction of the coil mass — singly or in combination — can account for changes in the extent of aneurysm occlusion observed over time; (5) even if an aneurysm could not be obliterated completely, treatment with GDC coils immediately after subarachnoid hemorrhage appeared to confer a protective effect upon patients compared to the natural history of untreated, ruptured intracranial aneurysms. In summary, these studies support the following conclusions regarding GDC-mediated electrothrombosis for the treatment of aneurysms: (1) aneurysm morphologies that are the most troublesome to treat by a conventional open surgical approach are also the most difficult to treat endovascularly; (2) although a useful therapeutic option for high-risk surgical candidates after aneurysmal hemorrhages, the endovascular treatment of intracranial aneurysms (basilar or otherwise) as more than a temporizing (i.e., not curative) intervention is not yet supported by data; (3) when comparing the complications and expenses associated with open surgical and endovascular therapy for aneurysms, long-term morbidity and cost analyses must incorporate the respective requirements for subsequent angiographic evaluation and repeat treatment sessions to address aneurysm residuals; (4) limited clinical and angiographic follow-up data preclude conclusions regarding the value of endovascular treatment for the management of asymptomatic aneurysms; (5) direct clip ligation of intracranial aneurysms remains the definitive treatment strategy until appropriate prospective, controlled, randomized studies prove otherwise.     

Supranuclear ophthalmoplegia with basilar artery aneurysms

In two patients, large aneurysms of the basilar artery produced a supranuclear gaze paresis, involving horizontal gaze in one case and vertical gaze in the other. In both cases the diagnosis was suggested by computed tomography and confirmed by vertebral angiography. Autopsy findings in one case confirmed the diagnosis. Although supranuclear gaze palsies must reflect damage to structures deep within the brain stem, these cases illustrate that an extrinsic lesion may produce such damage indirectly. Basilar artery aneurysm should be considered in patients presenting with supranuclear gaze paresis and long tract signs.     

基底动脉分叉部动脉瘤夹闭的手术体会

目的分析两种不同的手术入路行夹闭基底动脉分叉部动脉瘤,探讨该手术入路方式、规范和改进手术操作等措施,提高手术成功率和改善患者预后。方法回顾性分析10例基底动脉分叉部动脉瘤在显微镜下经两种不同手术入路夹闭治疗的临床资料。结果 10例患者术后存活9例,1例患者术前患合并多种并发疾病,全身状况差,术后1个月因多器官功能衰竭死亡。结论根据基底动脉分叉部动脉瘤的形态、位置采用不同的手术入路进行规范夹闭术操作,能提高手术成功率,改善患者预后。     

Treatment of basilar artery bifurcation aneurysms by using Guglielmi detachable coils: a 6-year experience

OBJECT: The authors retrospectively analyzed the results of their 6-year experience in the treatment of basilar artery (BA) bifurcation aneurysms by using Guglielmi detachable coils (GDCs). METHODS: This analysis involved 45 BA tip aneurysms in 16 men and 29 women who ranged in age from 23 to 78 years (mean 50 years). Seventy-five percent of the aneurysms had ruptured and 25% remained unruptured. Of the group whose aneurysms hemorrhaged, 14 patients were Hunt and Hess Grade I or II and 20 were Hunt and Hess Grades III to V; 32 patients were treated within 2 weeks of their subarachnoid hemorrhage (SAH). Initially, treatment with GDCs was limited to poor-grade high-risk patients who refused surgery or patients in whom surgery proved unsuccessful. Later in the study, good-grade patients with narrow-necked aneurysms were also treated using GDCs. The length of clinical follow up ranged from 1 to 72 months (average 27.4 months) in the 37 surviving patients. In 33 of the 45 aneurysms treated with coil placement, good to excellent results were achieved. There were 12 poor results (27%) including one in a patient from the non-SAH group who suffered a thrombotic complication due to an underlying vasculitis. Eight deaths were recorded in this group of 45 patients. One of these deaths was caused by a complication related to anesthesia, one by unknown causes, and six resulted from complications of the disease. One patient rebled on the 2nd day after the endovascular procedure. The mortality and permanent morbidity rates directly related to the intervention were 2.2% and 4.4%, respectively. Angiographic studies obtained immediately postintervention demonstrated 99 to 100% occlusion in 30 (67%) of the aneurysms; nine (20%) were more than 90% occluded; and six (13%) were less than 90% occluded by the GDCs. Follow-up angiograms were obtained in 31 patients between 2 and 72 months after coil placement. Nineteen (61%) of the follow-up angiograms revealed stable results (that is, no change from initial treatment). Twelve of the 31 showed coil compaction, but only eight of these lesions could accept additional coils. In large aneurysms recanalization was seen in 57%, and some of the larger lesions required as many as four embolizations (mean 1.7) to achieve optimal occlusion. When small-necked aneurysms were analyzed as a subset, a stable angiographic result was seen in 92%. CONCLUSIONS: Use of GDCs led to excellent clinical and angiographic results in the majority of patients with BA tip aneurysms included in this limited follow-up study. Rebleeding was encountered in one of the 34 previously ruptured BA aneurysms treated with GDCs, and no hemorrhages have been documented in the 11 unruptured aneurysms treated with GDCs in this series. Long-term follow-up studies are necessary before it is possible to compare adequately the treatment of aneurysms with coil placement to the gold standard of aneurysm clipping.     

Variant aneurysms of the fenestrated basilar artery

Two cases of aneurysm occurring on a fenestrated basilar artery are reported. One patient had a saccular aneurysm in the typical location at the vertebrobasilar junction at the proximal end of the fenestrated basilar segment. The aneurysm sac projected dorsally into the brain stem. The other patient had a blister-like aneurysm distal to a fenestration of the terminal basilar artery. The development of a distal aneurysm on a fenestrated basilar artery is predictable based on the reported morphology of the vessel wall in this vascular anomaly.     

Zygomatic temporopolar approach for basilar artery aneurysms

For surgery of upper basilar artery aneurysms, we have modified the temporopolar approach proposed by Sano by detaching the zygomatic arch to obtain a wide, shallow operating field. This approach seems to be suitable for anteriorly protruding, high-positioned, or large aneurysms of the upper basilar artery. We have used this zygomatic temporopolar approach in 4 patients with such aneurysms and obtained satisfactory results. In this paper, we detail the operative procedure and emphasize certain technical points to minimize temporal lobe retraction and to prevent oculomotor and facial nerve injuries.     

Endovascular treatment of basilar artery trunk aneurysms

Background  

There has been little reported on the endovascular experience of basilar artery (BA) trunk aneurysms due to its low incidence. The purpose of this study is to report the results of endovascular treatment (EVT) of BA trunk aneurysms.     

Microneurosurgery for aneurysms of the basilar artery.

The authors report microsurgical treatment in 32 cases of basilar artery aneurysms, operated on with good results in 28 cases, fair results in one, and poor results in one; there were two deaths. Twenty-nine patients (91%) were able to return to social activities. Characteristics of the surgical techniques include 1) taking a transsylvian route; 2) retracting the M1 portion of the middle cerebral artery (occasionally the C1 portion of the internal carotid) medially with tapered brain retractors; and 3) approaching the aneurysm through and between perforators arising from the posterior cerebral artery in cases of high-placed basilar bifurcation. With regard to instrument improvements, tapered brain retractors, a multipurpose head frame, and bayonet clips (Sugita design) proved very helpful.     

Direct surgery for carotid bifurcation artery aneurysms

Eighteen patients with bifurcation of internal carotid artery aneurysms were treated with direct surgery. In all cases the pterional approach was used. The strategy used in dissecting the aneurysm depends on the size of the aneurysm and the length of the intracranial internal carotid artery. When the aneurysm is small, the bifurcation of the internal carotid artery can be exposed by dissecting along the internal carotid artery from a proximal-to-distal direction. The aneurysm and the perforating vessels adjacent to it are identified before the aneurysm is clipped. When the aneurysm is not small or if the intracranial segment of the internal carotid artery is long, the sylvian fissure has to be dissected open before dissection of the aneurysm and perforators is undertaken. Using this dissection strategy, 18 bifurcations of internal carotid artery aneurysms were clipped with 16 excellent, one good, and one fair result. There was no mortality.     

Internal carotid artery bifurcation aneurysms: surgical experience

Internal carotid artery (ICA) bifurcation aneurysms are relatively uncommon and frequently rupture at a younger age compared to other intracranial aneurysms. We have treated a total of 999 patients for intracranial aneurysms, of whom 89 (8.9%) had ICA bifurcation aneurysms, and 42 of the 89 patients were 30 years of age or younger. The present study analyzed the clinical records of 70 patients with ICA bifurcation aneurysms treated from mid 1997 to mid 2003. Multiple aneurysms were present in 15 patients. Digital subtraction angiography films were studied in 55 patients to identify vasospasm and aneurysm projection. The aneurysm projected superiorly in most of these patients (37/55, 67.3%). We preferred to minimize frontal lobe retraction, so widely opened the sylvian fissure to approach the ICA bifurcation and aneurysm neck. Elective temporary clipping was employed before the final dissection and permanent clip application. Vasospasm was present in 24 (43.6%) of 55 patients. Forty-eight (68.6%) of the 70 patients had good outcome, 14 (20%) had poor outcome, and eight (11.4%) died. Patients with ICA bifurcation aneurysms tend to bleed at a much younger age compared to those with other intracranial aneurysms. Wide opening of the sylvian fissure and elective temporary clipping of the ICA reduces the risk of intraoperative rupture and perforator injury. Mortality was mainly due to poor clinical grade and intraoperative premature aneurysm rupture.     

Transpetrosal approach for aneurysms of the lower basilar artery

Extradural subtemporal access to the petrosal ridge and a resection of the anterior pyramidal bone produced direct observation of the lower basilar artery, with minimum retraction of the temporal lobe and preservation of the temporal bridging veins. Two patients with lower basilar trunk aneurysms facing toward the brain stem, were operated on by the "transpetrosal approach," with successful clipping of the aneurysms. Auditory function was preserved in one case. This approach decreases the possibility of retraction damage to the temporal lobe, brain stem, or cranial nerves, and may be helpful for surgery of aneurysms arising around the vertebrobasilar junction or at the origin of the anterior inferior cerebellar artery.