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.     

Management-Related Morbidity and Mortality in Unselected Aneurysms of the Basilar Trunk and Vertebrobasilar Junction

Summary  Objects. To analyze the management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction. The secondary objective was to investigate the factors associated with favourable or unfavourable surgical outcome in order to define subgroups for surgical and endovascular treatment.  Methods. 24 consecutive patients with aneurysms of the basilar trunk and vertebrobasilar junction were included in this study. They comprised 2.7% of all aneurysms treated during the study period between 1990 and 1997. 22 patients presented with acute subarachnoid hemorrhage (SAH) and 2 patients with symptoms of brainstem compresssion. All patients were managed using a standard protocol including surgery at the earliest possible moment, aggressive tripe-H therapy in patients with symptomatic vasospasm and mandatory follow-up angiography. 23 patients underwent surgical clipping and one patient endovascular coiling of the aneurysm. 12 patients had an excellent outcome. 6 patients had a good outcome, resulting in a total of satisfactory outcomes in 18 patients (75%). 4 patients (17%) had moderate to severe deficits. Two patients died (8%). Both patients had fusiform basilar trunk aneurysms. Good or excellent outcome was observed in 7 of 8 patients with aneurysms of the vertebrobasilar junction, 13 of 14 patients with moderate or minor SAH or without SAH (Fisher grade 0 to 2) and all patients with small sized aneurysm (n=6). Factors mostly associated with poor outcome or death after surgical treatment were aneurysm location at the basilar trunk, large aneurysm size or fusiforme aneurysm type and severe SAH.  Conclusions. Location, aneurysm size and the severity of SAH may help to predict the subgroup which highly benefits from surgical clipping of these rare vascular lesions.     

A transcavernous-transsellar approach to the basilar tip aneurysms

A series of 11 patients with a basilar tip aneurysm were treated operatively. The aneurysm had ruptured in all cases and caused at least one haemorrhage prior to surgery. Four patients harboured large aneurysms, while in the rest of them the aneurysms were small in size. In all the 11 patients a modified pterional transcavernous-transsellar approach was used which considerably facilitated clipping and secured complete exclusion of all aneurysms, including the large ones. Eight patients made a complete recovery and resumed their original occupation. One is hemiparetic but capable of self care, one is hemiplegic, and one died after surgery. The purpose of this report is to present our modified surgical approach to basilar tip aneurysms, which provides good exposure of the entire region of the bifurcation of the basilar artery and adjacent blood vessels as far as the anterior inferior cerebellar arteries, and requires but minimal retraction of the brain.     

Combined transsylvian-subtemporal exposure of cerebral aneurysms involving the basilar apex

The surgical repair of cerebral aneurysms involving the apex of the basilar artery continues to undergo refinement and evolution. The inherent difficulty in accessing the basilar apex as well as the complexities of the microanatomy render this area a notoriously hazardous and technically challenging region in which to perform microsurgical clipping of cerebral aneurysms. Several operative approaches have been described and are constantly undergoing a state of evolution in the hopes of optimizing the exposure of the distal basilar artery and minimizing the inherent risks of surgery. The consistent decline in operative morbidity has paralleled improved understanding of the microvascular anatomy, both in this region and along the various corridors of approach. No single operative approach is universally superior, considering the wide variability of individual patient anatomy and vascular configurations. Each approach has strengths, weaknesses, and potential complications that must be considered in the thought process of planning an operative attack on a basilar apex aneurysm. Intimate familiarity with the microvasculature and the microsurgical anatomy of the region is an imperative prerequisite for the application of any surgical approach to this region. This paper outlines a detailed review of the microsurgical anatomy that is pertinent to microsurgery of aneurysms in this region, and describes an approach referred to as the combined transsylvian-subtemporal approach. We have found this operative approach particularly useful in aneurysm surgery of the basilar apex but do not mean to imply that this single approach is suitable for all surgeons or all patients. This paper is designed to discuss an approach and microanatomic understanding that we find useful in the surgical treatment of aneurysms involving the basilar apex. © 1994 Wiley-Liss, Inc.     

Surgical management of vertebral and basilar artery aneurysms: a single center experience in 41 patients

Objective

To study an effective method for surgical management of vertebral and basilar artery aneurysms.

Methods

Forty-one patients with 43 aneurysms of the vertebral and basilar arteries were managed by microsurgical clipping. Cerebral angiography revealed basilar apex aneurysms in 17 patients, basilar trunk in six patients, vertebrobasilar (VB) junction aneurysms in three patients and vertebral aneurysms in 15 patients. One patient had two basilar aneurysms, and another had bilateral vertebral artery aneurysm.

Surgical technique

We used a pterional approach in basilar apex aneurysms (n?=?17 patients), orbitozygomatic and its variants in upper basilar trunk aneurysms (n?=?2 patients), combined petrosal and far-lateral approach in mid basilar trunk aneurysms (n?=?4 patients), far-lateral and transcondylar approach for the aneurysms at VB junction (n?=?3 patients) and transcondylar approach for the vertebral aneurysms (n?=?15 patients). Bypass graft was performed in 14 patients with fusiform and wide neck aneurysms, to prevent potential cerebral ischemia due to prolonged temporary occlusion or possibility of intraoperative parent artery sacrifice.

Results

Neurological outcomes were measured on the basis of Glasgow Outcome Score (GOS). The rate of back-to-normal life after surgery in basilar tip aneurysm, basilar trunk aneurysms, VB junction aneurysms and vertebral artery aneurysms was 15/17 (82.5 %), 5/6 (83 %), 3/3 (100 %) and 14/15 (93.3 %), respectively. Thirty-six (87.8 %) patients had uneventful postoperative courses. Two patient with basilar apex aneurysm suffered severe neurological deficits related to midbrain ischemia, two patient with occipital artery (OA) graft bypass had postoperative partial lower cranial nerve palsy, and one death with basilar trunk aneurysm occurred after the 20th day of surgery. Thirty-nine patients accepted postoperative digital subtraction angiography (DSA) and eight patients accepted computed tomography (CT) angiogram, whereas two patient denied either one. All the images demonstrated afferent and efferent vessels without aneurysm in situ. Out of 14 patients with graft bypass, 11 patients on cerebral angiographies disclosed the aneurysm clip and the graft bypass patency, one patient on angiography had unidentified graft bypass patency but no symptom related to the graft bypass patency, and two patients denied the postoperative cerebral angiographies. In 40 patients with a mean follow-up of 3.4 years, 37 patients had good outcome, two patients needed assistance for daily living, and one death occurred due to brainstem infarction related to surgery.

Conclusion

Selection of proper cranial base approach with adequate exposure is effective in clipping VB aneurysms, minimizing the postoperative complications. Graft bypass may avoid parent artery sacrifice and its branches occlusion in patients with fusiform and wide neck aneurysms.     

Skull Base Approaches for Posterior Circulation Aneurysms

With the emergence of skull base surgery, surgical approaches have been developed and redefined, providing surgeons with accessible avenues to difficult lesions of the cranial base. Although the majority of lesions to which these techniques have been applied have been for tumors, we find that these skull base approaches can equally provide access to difficult vascular lesions, especially complex aneurysms of the posterior circulation. In this report three different skull base approaches were used in four patients for the treatment of posterior circulation aneurysms. A cranio-orbital-zygomatic approach was used for the acute stage of a ruptured basilar tip artery anenrysm and for a giant posterior cerebral artery aneurysm. A petrosal approach was used for a ruptured basilar trunk aneurysm, and the transcondylar approach was used for a vertebral artery aneurysm. Each approach provides a wide field and excellent exposure of vital structures with minimal brain retraction. Neck clipping of the aneurysms was successfully achieved in all cases. We believe that our skull base approaches facilitate the surgical treatment of posterior circulation aneurysms.     

Skull base approaches for posterior circulation aneurysms

With the emergence of skull base surgery, surgical approaches have been developed and redefined, providing surgeons with accessible avenues to difficult lesions of the cranial base. Although the majority of lesions to which these techniques have been applied have been for tumors, we find that these skull base approaches can equally provide access to difficult vascular lesions, especially complex aneurysms of the posterior circulation. In this report three different skull base approaches were used in four patients for the treatment of posterior circulation aneurysms. A cranio-orbital-zygomatic approach was used for the acute stage of a ruptured basilar tip artery anenrysm and for a giant posterior cerebral artery aneurysm. A petrosal approach was used for a ruptured basilar trunk aneurysm, and the transcondylar approach was used for a vertebral artery aneurysm. Each approach provides a wide field and excellent exposure of vital structures with minimal brain retraction. Neck clipping of the aneurysms was successfully achieved in all cases. We believe that our skull base approaches facilitate the surgical treatment of posterior circulation aneurysms.     

Basilar artery trunk saccular aneurysms: morphological characteristics and management

The purpose of this retrospective study was to report the morphological characteristics and results of surgical and endovascular treatment of basilar artery (BA) trunk saccular aneurysms. Twenty-two patients with 22 BA trunk saccular aneurysms underwent surgery including endovascular intervention. In this series, BA trunk aneurysms showed characteristic features such as so-called lateral aneurysm (41%), multiple aneurysms (32%), including two de novo aneurysms, and various vascular anomalies. Eleven craniotomies for neck clipping were performed for 11 ruptured aneurysms. However, in one of these cases, we abandoned neck clipping, because of concern for neck tearing, and embolized it later. Five ruptured and five unruptured aneurysms were successfully treated by endovascular surgery. Another one incompletely embolized aneurysm had grown to a huge size, and the patient underwent a Hunterian ligation with a flow reconstruction. The unusually high incidence of various associated vascular anomalies suggests that focal wall weakness must be based on the mechanism of aneurysm initiation. Most patients presented with subarachnoid hemorrhage. The pretreatment neurological state was predictive for clinical outcome. And, clinical outcomes in this series were not affected by the choice of treatment. However, considering that three of 11 surgical cases needed subsequent treatment, endovascular surgery should be considered as a first choice.     

Bypass-surgery and coil-embolisation in the treatment of cerebral giant aneurysms

OBJECTIVE: Operative clipping is the most effective method in the treatment of cerebral giant aneurysms. But about 50% of all giant aneurysms are treatable this way. We want to report about eight patients with giant cerebral aneurysms, which were in our opinion "unclippable" without causing ischaemia in depending brain areas. METHODS: We describe eight cases of giant aneurysms of the pericallosal artery (n = 1) the middle cerebral artery (n = 3), the basilar tip (n = 3) and of the upper part of the basilar artery (n = 1). One patient with an aneurysm of the pericallosal artery was treated with an extra-intracranial saphenous vein bypass saphenous bypass, in three cases of middle cerebral artery aneurysms an extra-intracranial bypass was also done combined with a resection of the aneurysm. The four patients suffering from an aneurysm of the basilar artery got an extra intracranial bypass too followed by an occlusion of the aneurysm with GD-Coils. RESULTS: There was no peri-operative mortality and no severe peri- or postoperative complication. The neurological symptoms of all patients were unchanged after the operation. An angiographic control showed a complete obliteration of the aneurysm and a free running bypass in all cases. CONCLUSION: Bypass surgery and combined bypass surgery and coil embolisation are effective methods in the treatment of giant cerebral aneurysms, which can not be treated by clipping alone.     

Extracorporeal circulation with deep hypothermia and circulatory arrest in the treatment of intracranial arterial aneurysms

Extracorporeal circulation with circulatory arrest and deep hypothermia in surgery on certain giant intracranial arterial aneurysms or on aneurysms difficult to access is described. The series includes a giant left carotid aneurysm, an aneurysm of the basilar artery bifurcation, a patient with two aneurysms, one on the right middle cerebral artery and the other at the end of the basilar artery, and a fourth patient with two aneurysms, one on the right middle cerebral and the other on the right carotid. Closed-thorax extracorporeal circulation with femoral cannulation was performed on all the patients. Surgical procedure is described and the advantages and disadvantages discussed. Results are encouraging. The authors suggest that the technique be used during surgical treatment of certain intracranial aneurysms that are in awkward positions or are very large in size. They emphasize that the procedure should be confined to exceptional cases.     

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.     

Intraoperative angiography and temporary balloon occlusion of the basilar artery as an adjunct to surgical clipping: technical note.

The direct surgical treatment of intracranial aneurysms is not always possible, especially in posterior circulation aneurysms. This is usually because of their complex anatomy and location next to the skull base and brain stem, where proximal vascular control is usually not attainable. Four patients at our institution underwent intraoperative transfemoral catheterization of the basilar artery with a nondetectable endovascular balloon for proximal control of the basilar artery. The flow control in the basilar artery was excellent and facilitated the surgery. Before surgery, each patient underwent the placement of a 10-cm 8-French femoral introducer sheath and were taken to the operating room where they were placed in a supine position and a subtemporal or pterional craniotomy was performed. After the initial exposure and before aneurysm manipulation, a nondetachable silicone balloon catheter was passed through an introducer catheter and was placed into the rostral basilar artery, using flow direction, microguidewires, and angiographic "road-mapping" techniques. In two patients, temporary basilar occlusion was used to collapse the aneurysm and to facilitate clip placement. In the third patient, intraoperative aneurysm rupture occurred and was controlled by temporary basilar artery occlusion. Using intraoperative angiography, complete aneurysm obliteration and vessel patency was confirmed in all four patients. All patients made a complete recovery except for initial postoperative third nerve palsies in three patients. This technique achieves intraoperative control of the basilar artery proximal to an aneurysm by the use of a nondetachable occlusive balloon in the basilar artery. An added benefit is the ease with which intraoperative angiography can be obtained in this context.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fenestrated basilar artery aneurysm: case report]

The authors reported an operated case with an aneurysm arising from the proximal end of basilar artery fenestration, and discussed its etiology and surgical strategy. A 47-year-old woman presented with slight memory disturbance. Neuroradiologic examination revealed an aneurysm located on the proximal end of the basilar artery 12 x 9 mm in size at the level of the outer auditory meatus. The union of vertebral arteries had deviated toward the right side, and the aneurysmal dome had projected into the fenestration. Through the right far lateral approach, we applied two straight fenestrated clips X configuration to the aneurysm. Several authors have reported a variety of approaches for vertebrobasilar aneurysms along the midline with consideration of the height of the aneurysmal. However, another point of view is that attention should be paid to the direction of the clip blade and applied at the final clipping, because, for vertebrobasilar aneurysms adjacent to the midline, the surgical view and working space are extremely restricted.     

Treatment of ruptured intracranial aneurysms: our approach.

OBJECTIVE: Subarachnoid hemorrhage (SAH) often results in devastating neurological deficits requiring hospitalization and loss of independence. This is often a difficult time for patients and their families who are struggling to cope with this sudden illness. Current treatment options include surgical clipping of the aneurysm or endovascular obliteration using Guglielmi detachable coils. Our purpose in writing this paper was to review the factors that determine the choice of treatment. In addition to this we wanted to study the benefits of surgical clipping for ruptured aneurysms over endovascular coiling. MATERIAL AND METHODS: We studied--retrospectively--450 cases of ruptured cerebral aneurysms admitted to our institution from 1997 to 2003. Out of these, 324 were subjected to surgical clipping and 126 to endovascular techniques. The outcome was studied using the Glasgow Outcome Score (GOS). RESULTS: Of the 324 cases of surgical clipping 222 had a good recovery, 38 had moderate disability, 15 had severe disability, 13 became vegetative and 36 patients died. In the endovascular group 34 had a good recovery, 22 had moderate disability, 18 had severe disability, 15 became vegetative and 37 patients died. Grade to Outcome was compared for both forms of treatment. In our series clipping for ruptured aneurysm was preferred to coiling in fusiform-shaped aneurysms, large or giant aneurysms, MCA aneurysms, blister aneurysms, complex configurations, partially thrombosed aneurysms and aneurysms associated with cerebral hemorrhage. Coiling was performed for basilar tip and trunk aneurysms, high anterior communicating artery aneurysms, patients in subacute stages of subarachnoid hemorrhage, and those with associated medical complications. CONCLUSION: Based on this study we were able to formulate a few definite indications for clipping, even in the times of advanced endovascular techniques. In addition we could also prove the benefits of surgical clipping over the endovascular technique in severe subarachnoid hemorrhage.     

The use of electroencephalography and brain protection during operation for basilar aneurysms

Intraoperative monitoring with electroencephalography and the use of brain protection with steroids, phenytoin, mannitol, and pentobarbital or etomidate were evaluated in 15 patients undergoing operation for an aneurysm of the upper basilar artery. One patient harbored a basilar trunk aneurysm, 1 an aneurysm of the proximal posterior cerebral artery, 3 an aneurysm of the superior cerebellar artery, and 10 an aneurysm at the basilar tip. The size of the aneurysms varied between 5 and 30 mm. Subarachnoid hemorrhage was the symptom exhibited in 12, mass effect the symptom in 2, and 1 patient was asymptomatic but had an angiogram because of amaurosis. There were 9 patients with multiple aneurysms, 5 of whom had aneurysms of the bilateral anterior circulation. Four patients underwent operation early. In 2 patients, the basilar artery was the sole or main blood supply of the whole brain. All patients except the one with the basilar trunk aneurysm were operated on via a transsylvian approach. All patients received 500 to 800 mg of phenytoin and 10 to 20 mg of dexamethasone shortly before and during surgery, and mannitol (0.8 g/kg) 15 minutes before the induction of hypotension or temporary clipping. Three patients showed slowing of electrical activity over the right hemisphere as a result of retraction of the internal carotid artery; with repositioning of the retractor, this disappeared within 10 minutes. Electrocortical silence was induced in 8 patients; this was in anticipation of prolonged moderate hypotension in 2, short deep hypotension in 2, temporary clipping of major vessels--including the basilar artery--in 2, and a combination of deep hypotension combined with temporary clipping in 2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Three-dimensional computerized tomography angiography-guided surgery of acutely ruptured cerebral aneurysms

OBJECT: The aim of this study was to assess whether aneurysm surgery can be performed in patients with ruptured cerebral aneurysms by using three-dimensional computerized tomography (3D-CT) angiography alone, without conventional catheter angiography. METHODS: In a previous study, 60 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms were prospectively evaluated using both 3D-CT and conventional angiography, which resulted in a 100% accuracy for 3D-CT angiography in the diagnosis of ruptured aneurysms, and a 96% accuracy in the identification of associated unruptured aneurysms. The results led the authors to consider replacing conventional angiography with 3D-CT angiography for use in diagnosing ruptured aneurysms, and to perform surgery aided by 3D-CT angiography alone without conventional angiography. Based on the results, 100 consecutive patients with SAH who had undergone surgery in the acute stage based on 3D-CT angiography findings have been studied since December 1996. One hundred ruptured aneurysms, including 41 associated unruptured lesions, were detected using 3D-CT angiography. In seven of 100 ruptured aneurysms, which included four dissecting vertebral artery aneurysms, two basilar artery (BA) tip aneurysms, and one BA-superior cerebellar artery aneurysm, 3D-CT angiography was followed by conventional angiography to acquire diagnostic confirmation or information about the vein of Labbé, which was needed to guide the surgical approach for BA tip aneurysms. All of the ruptured aneurysms were confirmed at surgery and treated successfully. Ninety-three patients who underwent operation with the aid of 3D-CT angiography only had no complications related to the lack of information gathered by conventional angiography. The 3D-CT angiography studies provided the authors with the aneurysm location as well as surgically important information on the configuration of its sac and neck, the presence of calcification in the aneurysm wall, and its relationship to the adjacent vessels and bone structures. CONCLUSIONS: The authors believe that 3D-CT angiography can replace conventional angiography in the diagnosis of ruptured aneurysms and that surgery can be performed in almost all acutely ruptured aneurysms by using only 3D-CT angiography without conventional angiography.     

Basilar apex aneurysms: surgical results and perspectives from an initial experience

OBJECTIVE: To demonstrate that well-trained neurosurgeons can successfully treat patients with basilar apex aneurysms, to encourage young neurosurgeons in appropriate clinical environments to develop this expertise, and to describe a personal experience with an initial series. METHODS: In a consecutive series of 500 aneurysms treated surgically over 3.5 years, 57 aneurysms in 56 patients were located at the basilar apex, 47% of which were large or giant in size. RESULTS: Most aneurysms (77%) were treated by direct clipping through an orbitozygomatic-pterional transsylvian approach. The surgical mortality rate was 9%, and permanent neurological morbidity associated with treatment occurred in 5%. Good outcomes (Glasgow Outcome Scale score 5 or 4) were achieved in 84%. Good outcomes increased from 79% in the first half of the series to 90% in the second half, and the mortality rate decreased from 21 to 4%. CONCLUSION: Young neurosurgeons can acquire technical proficiency with basilar apex aneurysms while achieving optimal patient outcomes. Young neurosurgeons with the right training, talent, and temperament are needed to deal with those patients with basilar aneurysms who require surgery and with a possible shortage of basilar aneurysm surgeons in the future. The learning curve is characterized by increased temporary clipping, better perforator dissection, and more sophisticated permanent clipping technique. The path to proficiency can be as demanding mentally as it is technically.     

Endovascular treatment of posterior circulation aneurysms by electrothrombosis using electrically detachable coils.

In a multicenter study, 120 patients with intracranial aneurysms presenting a high surgical risk were treated using electrolytically detachable coils and electrothrombosis via an endovascular approach. The results of treatment in patients with posterior fossa aneurysms (42 patients with 43 aneurysms) are presented. The most frequent clinical presentation was subarachnoid hemorrhage (24 cases). The clinical follow-up periods ranged from 1 week to 18 months. Complete aneurysm occlusion was obtained in 13 of 16 aneurysms with a small neck and in four of 26 wide-necked aneurysms. A 70% to 98% thrombosis of the aneurysm was achieved in 22 of 26 aneurysms with a wide neck and in three of 16 small-necked aneurysms. One aneurysm could not be treated due to a technical complication. Two cases required postprocedural surgical clipping of a residual aneurysm. One patient (originally in Hunt and Hess Grade V) experienced procedural rupture of the aneurysm requiring an emergency parent artery occlusion. He eventually died 5 days later. Another patient (originally in Grade IV) had coil migration and posterior cerebral artery territory ischemia. A third patient developed a permanent neurological deficit (hemianopsia) after complete occlusion of a wide-necked basilar bifurcation aneurysm. One patient, harboring an inoperable giant basilar bifurcation aneurysm, died from aneurysm bleeding 18 months after partial occlusion. Overall morbidity and mortality rates related to treatment were 4.8% (two cases) and 2.4% (one case), respectively (2.6% and 0% if considering only patients in Hunt and Hess Grades I, II, and III). It is suggested that this technique is a viable alternative in the management of patients with posterior fossa aneurysms associated with high surgical risk. Longer angiographic and clinical follow-up study is necessary to determine the long-term efficacy of this recently developed endovascular occlusion technique. Close postoperative angiographic and clinical monitoring of patients with wide-necked subtotally occluded aneurysms is mandatory to check for potential aneurysmal recanalization, regrowth, and rupture.     

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 trunk aneurysm associated with fenestration of the basilar artery

Basilar trunk saccular aneurysms associated with fenestration are infrequent, especially in the middle or distal portion of the basilar artery. Surgical treatment of the basilar trunk aneurysm is difficult, due to its anatomical environment and the complicated surgical exposure. A 46-year-old woman presenting with Hunt and Kosnik grade II subarachnoid hemorrhage was found to have a ruptured aneurysm arising at the proximal corner of the associated fenestration in the middle portion of the basilar artery. Because of surgical difficulties anticipated in approaching the aneurysm, it was decided to treat it with endovascular embolization utilizing the Guglielmi detachable coil; and complete occlusion of the aneurysm was obtained. The efficacy of endovascular treatment for the basilar trunk aneurysm with associated fenestration is discussed from anatomical and embryological points of view, and relevant literature is reviewed. Received: 16 December 1998 / Accepted: 14 February 1999