Pericallosal aneurysms

Endovascular treatment of distal anterior cerebral artery aneurysms using flow modulation devices: mid- and long-term results from a two-center study

Purpose

Flow-diverter (FD) stents have become an established treatment for intracranial aneurysms in recent years, but their use for aneurysms in distal cerebral vessels with small carrier vessel diameters remains controversial. This study describes the method and mid- and long-term outcomes of FD treatment of distal anterior cerebral artery aneurysms (DACAAs) at two neurointerventional centers, to elucidate this topic and provide more in-depth data.

Methods

Data for all patients at two neurointerventional centers who were treated with FDs for DACAAs in the pericallosal and supracallosal segment of the anterior cerebral artery were retrospectively analyzed. Data on periprocedural complications, and short-, mid- and long-term follow-up findings were recorded.

Results

Forty-one patients were eligible for inclusion in the study. Three FD models were used, one of which had an anti-thrombotic coating. Two periprocedural complications (5%) occurred but did not cause a change in the mRS. In the long-term follow-up, at 29 months and beyond, 83% of assessable patients showed complete occlusion of the aneurysms without new neurological deficits.

Conclusion

FDs are a safe and effective treatment approach for DACAAs. This study indicated a low risk of complications, and high closure rates in short-, mid- and long-term follow-up.

Mirror image of bilateral DACA aneurysm with its successful surgical management

Background:

Among various locations of intracranial aneurysms reported in the literature, two different aneurysms situated symmetrically opposite on bilateral distal anterior cerebral arteries (DACA) are very rare.

Case Description:

Here, we report a rare case of mirror image distal anterior cerebral aneurysm in a middle-aged male patient. The patient presented with severe headache and loss of consciousness. Angiography was done which suggested mirror imaging of two aneurysms located over both DACA. It was treated through microsurgical approach with a successful outcome.

Conclusion:

Careful analysis of intracranial vasculature should be done using angiography, particularly in different views and stages to rule out multiple aneurysms at different locations in the same artery or at different arteries. Mirror images of bilateral DACA aneurysms are very rare. Fundamental surgical strategy of securing the parent artery and clipping the neck after meticulous dissection should be followed.

A5 segment aneurysm of the anterior cerebral artery, imbedded into the body of the corpus callosum: A case report

BACKGROUND

The A5 segment aneurysms of the anterior cerebral artery are rare, approximately 0.5% of all intracranial aneurysms. They are small with a wide base located in the midline, with the domes mostly projecting upward or backward.

CASE DESCRIPTION

The authors describe a unique case of A5 segment aneurysm, with the dome embedded into the body of the corpus callosum. This 41-year-old female was admitted to the neurology department for possible multiple sclerosis investigation. Computed tomography angiogram (CTA) revealed a 4-mm right-sided pericallosal artery aneurysm, with rare configuration, which was caudally projected, embedded into the body of the corpus callosum. Considering the family history, patient underwent a prophylactic ligation surgery. The postoperative CT and CTA showed no complication and successful occlusion of the aneurysm with no ischemia or hemorrhage in the corpus callosum.

CONCLUSION

To the best of our knowledge, this is the first case of an aneurysm with this configuration. Our rare case of A5 segment aneurysm demonstrates the importance of planning of the surgery, choosing the appropriate approach, and knowing the detailed anatomy of the region, as well as the necessity of microsurgical clipping of small unruptured AdistAs.

De novo giant A2 aneurysm following anterior communicating artery occlusion

BACKGROUND

De novo intracranial aneurysms are reported to occur with varying incidence after intracranial aneurysm treatment. They are purported to be observed, however, with increased incidence after Hunterian ligation; particularly in cases of carotid artery occlusion for giant or complex aneurysms deemed unclippable.

CASE DESCRIPTION

We report a case of right-sided de novo giant A2 aneurysm 6 years after an anterior communicating artery (ACoA) aneurysm clipping. We believe this de novo aneurysm developed in part due to patient-specific risk factors but also a significant change in cerebral hemodynamics. The ACoA became occluded after surgery that likely altered the cerebral hemodynamics and contributed to the de novo aneurysm. We believe this to be the first reported case of a giant de novo aneurysm in this location. Following parent vessel occlusion (mostly of the carotid artery), there are no reports of any de novo aneurysms in the pericallosal arteries let alone a giant one. The patient had a dominant right A1 and the sudden increase in A2 blood flow likely resulted in increased wall shear stress, particularly in the medial wall of the A2 where the aneurysm occurred 2 mm distal to the A1-2 junction.

CONCLUSION

ACoA preservation is a key element of aneurysm surgery in this location. Suspected occlusion of this vessel may warrant closer radiographic follow-up in patients with other risk factors for aneurysm development.

Endovascular treatment of fusiform A2 aneurysm with parent artery occlusion

Background:

A2 aneurysms are rare with a reported incidence of <1% of the intracranial aneurysms. These aneurysms are located between the anterior communicating artery and genu of the corpus callosum. Fusiform aneurysms in this location are even rarer and we present one such case of fusiform A2 aneurysm treated with endovascular technique.

Case Description:

In this report, we present a case of ruptured fusiform A2 or proximal pericallosal artery aneurysm in a middle-aged female who presented with subarachnoid hemorrhage. She subsequently underwent endovascular parent artery occlusion, and post-procedure angiogram showed good pial collaterals filling the distal territory. She developed transient lower limb weakness which improved over the next 24 h with supportive inotrope management to maintain adequate cerebral flow.

Conclusion:

We report a rare unique case of ruptured fusiform proximal pericallosal artery aneurysm. Endovascular treatment of this type of aneurysm is a feasible method and can be considered as an effective alternative to surgical technique.

Feasibility and efficacy of endovascular therapy for ruptured distal anterior cerebral artery aneurysms

Surgical clipping has been the primary treatment option for ruptured distal anterior cerebral artery (DACA) aneurysms. Therefore, the literature on endovascular therapy is sparse. The present study investigated the feasibility and efficacy of endovascular therapy for ruptured DACA aneurysms in 31 patients, 26 females and 5 males (mean age 63.2 ± 12.6 years). Mean aneurysm size and neck width were 4.8 ± 2.3 mm and 2.2 ± 0.7 mm, respectively. The Hunt and Hess (H/H) grades just prior to the treatment were scored as H/H grades 1-3 in 20 patients and H/H grades 4-5 in 11 patients. Fifteen patients had an intraparenchymal hematoma (IPH) surrounding the ruptured aneurysm on the initial computed tomography. Overall, 22 patients had a modified Rankin scale (mRS) score of 0-2 and 9 had a mRS score of 3-6 at discharge. H/H grade was closely related to the clinical outcomes, whereas the presence of IPH was not. Overall immediate angiographic outcomes were complete occlusion in 15, residual neck in 11, and residual aneurysm in 5. The overall recurrence rate was 35.3%. Complications including posttreatment rebleeding occurred in 5 patients. Symptomatic vasospasm occurred in 1 of the 18 patients with H/H grades 1-3. Endovascular therapy of ruptured DACA aneurysms is feasible and effective. However, the risks of recurrence and posttreatment bleeding remain to be resolved.

A case of thrombosed giant aneurysm of the azygos anterior cerebral artery: clipping under monitoring of motor evoked potentials of the lower extremities

Giant aneurysms of the distal anterior cerebral artery (ACA), especially the azygos ACA, are rare. We treated a patient with giant aneurysm of the azygos ACA who underwent aspiration of thrombus and clipping under monitoring of motor evoked potentials of the lower extremities (L-MEPs), resulting in remarkable recovery of motor and intellectual function. A 72-year-old male was admitted with left motor weakness persisting for 2 weeks. Neurologically, disorientation and intellectual impairment were also noted. Imaging disclosed a 60-mm diameter aneurysm with heterochronous thrombi arising from the distal bifurcation of the azygos ACA. One month after the onset, radical surgery was scheduled. The azygos ACA was secured and the aneurysm was dissected, and the distal parts of the azygos ACA were confirmed. After removal of the thrombus, the neck was reconstructed with eight clips. L-MEPs disappeared due to occlusion of the azygos ACA for 20 minutes but reappeared after 22 minutes and normalized 78 minutes after reperfusion. Motor weakness improved entirely with mini-mental state examination score of 29 points at 1 month after surgery. One year later, Wechsler Adult Intelligence Scale-Third Edition and Wechsler Memory Scale-Revised scores reached normal levels. Review of reported cases found this aneurysm tends to occur in males in their 50s to 70s presenting with mass sign. Decompression of the aneurysm in the frontal lobe and monitoring of L-MEPs during temporary occlusion of the ACA are important.

Thrombosed giant aneurysm of the distal anterior cerebral artery treated with aneurysm resection and proximal pericallosal artery-callosomarginal artery end-to-end anastomosis: Case report and review of the literature

BACKGROUND

Giant distal anterior cerebral artery (DACA) aneurysms are extremely rare, with only 32 cases reported in the literature. Most giant DACA aneurysms have features that make standard neck clipping difficult, and bypass surgery is sometimes required, although this surgery was performed in only three reported cases. This report presents the fourth case treated with bypass surgery.

CASE DESCRIPTION

A 69-year-old female presented with an unruptured thrombosed giant DACA aneurysm. She underwent wrapping operation 7 years before, but radiological imaging revealed enlargement of the aneurysm at the left pericallosal artery (PerA)-callosomarginal artery (CMA) junction. Before operation, three different strategies were considered for bypass surgery in case the neck could not be clipped. Aneurysm resection and left proximal PerA-CMA end-to-end anastomosis were successfully performed under intraoperative digital subtraction angiography (DSA) and motor-evoked potential (MEP) monitoring.

CONCLUSION

Most DACA aneurysms are located at the PerA-CMA junction. In some cases, adequate retrograde flow to the distal PerA from the posterior or middle cerebral artery can be expected, making distal PerA reconstruction unnecessary. Moreover, when the distal PerA is cut, proximal PerA-CMA end-to-end anastomosis can be easily performed because of reduced tension in both vessels. We therefore conclude that this strategy should be utilized for treating such patients. We also presented here the effectiveness of intraoperative modalities, such as intraoperative DSA and MEP monitoring, for performing a safe operation.

Aneurysms of the distal anterior cerebral artery: a clinical series

BACKGROUND AND PURPOSE

Distal anterior cerebral artery (DACA) aneurysms, also called pericallosal or A2 aneurysms, are rare and comprise about 1.5 to 9% of all intracranial aneurysms. In this study, a series of 10 patients with DACA aneurysms who were surgically treated in our clinic is presented and discussed, focusing on their clinical features and sur-gical outcomes.

MATERIAL AND METHODS

A total of 344 patients with cerebral aneurysms were operated on in our clinic and 10 patients (2.9%) with DACA aneurysms were studied retrospectively. All patients underwent a computed tomography (CT) scan followed by four-vessel digital subtraction angiography (DSA).

RESULTS

Initial CT revealed intracerebral haematoma (ICH) in 7 patients (70%) and in 2 of them the haematoma was over 3 cm in diameter. The pericallosal-callosomarginal bifurcation was the most common location in 9 patients (90%). Four cases (40%) showed multiple aneurysms. The mean waiting time for the operation was 4.8 days. Surgical clipping was performed in all the cases. Multiple aneurysms required two different craniotomies in the same session. The patients with ICH over 3 cm in diameter, in addition to poor preoperative grade, are likely to have a poor outcome, and so clinical grade is the definite factor affecting the surgical outcome of patients.

CONCLUSIONS

DACA aneurysms are usually small and bleeding occurs irrespective of their size because of the lack of resistant arachnoid membranes at the level of the pericallosal cisterns. All DACA aneurysms, even if very small in size or discovered incidentally, should be aggressively treated because of the high tendency to rupture.

The anatomy of the callosomarginal artery: applications to microsurgery and endovascular surgery

BACKGROUND

The callosomarginal artery (CMA), the main branch of the pericallosal artery, courses in or near the cingulate sulcus and gives rises to 2 or more major cortical branches. There is confusion about the artery best fitting the definition of "callosomarginal artery." Distal anterior cerebral artery aneurysms represent 1.5% to 9% of intracranial aneurysms, and most often occur at the origin of the CMA. The microsurgical anatomic features of the CMA, its relationship with the pericallosal artery, and clinical implications are presented.

METHODS

The origin, course, branching pattern, and diameter of the CMA and its branches and its relationship with the pericallosal artery were studied in 60 cerebral hemispheres, including cadaveric dissections and angiographic images.

RESULTS

The CMA was present in 93.3% of hemispheres studied and arose mainly from A3 (55.2%), a mean of 3.11 +/- 1.90 cm from the anterior communicating artery. The mean diameter of the CMA at its origin was 1.53 +/- 0.36 mm. The CMA ran 1.28 +/- 0.89 cm until its first branch, describing an anterior convex curve backward and upward (60.7%). An average of 3 lesser branches originated from the CMA. The most consistent branch was the posterior internal frontal artery (67.9%). The mean diameter of the CMA branches was 0.93 +/- 0.33 mm.

CONCLUSION

These morphometric measurements can help neurosurgeons access lesions located in distal intracranial vessels. The vessel coursing the longest pathway in or near the cingulate sulcus and otherwise following Moscow's classic definition should be considered the CMA.

The influence of configuration and location of ruptured distal cerebral anterior artery aneurysms on their treatment modality and results: analysis of our casuistry and literature review

OBJECTIVE

To assess the influence of configuration and location of ruptured distal cerebral anterior artery aneurysms on their treatment modality and results.

METHOD

The influence of the aneurysm configuration (basic or complex configuration) and location (infracallosal or supracallosal) on the treatment-related radiological results (partial or complete aneurysm occlusion) and clinical outcome (favorable or unfavorable) was retrospectively analysed in all admitted patients with ruptured pericallosal aneurysms within the last 10 years. The expected benefit from each form of treatment was individually discussed.

RESULTS

During this period, 21 patients with ruptured pericallosal aneurysms (three previously coiled in other departments) had been admitted to our department. Within the endovascular group (ten patients), five infracallosal basic aneurysms presented a complete occlusion and favorable patient outcome. Three patients with infracallosal complex aneurysms presented a favorable outcome (two aneurysms were partially occluded and a frustrated procedure was replaced by clipping). Two supracallosal basic aneurysms showed a complete occlusion with one unfavorable outcome and one frustrated procedure followed by clipping and favorable outcome. In the surgical group (11 patients), five infracallosal complex aneurysms presented a complete occlusion with four favorable and one unfavorable outcomes. One patient with a supracallosal basic aneurysm presented a complete occlusion with a favorable outcome, and five patients with supracallosal complex aneurysms presented a complete occlusion in four cases and favorable outcome in all of them.

CONCLUSION

The results of this study suggest that patients with infracallosal basic configured aneurysms are expected to benefit from endovascular procedures, whereas better radiological and clinical results can be obtained in surgically treated patients harboring supra- or infracallosal aneurysms of complex configuration.

Large distal anterior cerebral artery aneurysm treated with resection and interposition graft: case report

OBJECTIVE

Distal anterior cerebral artery (DACA) aneurysms are rare, representing only 2% to 6.7% of all intracranial aneurysms. Most of them are small. Large and giant aneurysms are even rarer in this location. Only 26 giant pericallosal (PC) aneurysms have been reported thus far. Various surgical techniques have been used to treat these aneurysms, including direct aneurysm neck clipping, aneurysm trapping, proximal occlusion of the anterior cerebral artery, or a combination of clipping with coiling or a bypass procedure. The report presents an unusual case of a complex DACA aneurysm managed by resection and interposition arterial graft.

CLINICAL PRESENTATION

A 69-year-old woman presented with acute onset of a severe headache. A digital subtraction angiogram showed a partially thrombosed, complex broad-necked A2-A3 junction aneurysm involving the origin of PC and callosomarginal vessels with a probability of a dissection of the DACA. The left PC artery was significantly narrowed. Because of the complex neck and involvement of the origin of PC and callosomarginal arteries, endovascular treatment was not possible, and microsurgical treatment was planned.

TECHNIQUE

A large, partially thrombosed, and fusiform anterior cerebral artery A2-A3 aneurysm, with evidence of previous bleeding, was found and treated with resection and a short interposition graft using a segment of the superficial temporal artery.

CONCLUSION

Surgical treatment of a large DACA aneurysm may be difficult due to a complex neck and the involvement of the branch vessels. Resection and interposition grafting and A3-A3 or A4-A4 anastomoses are treatment options for such patients.

Distal anterior cerebral artery aneurysms: treatment and outcome analysis of 501 patients

OBJECTIVE

This study presents the combined experience of two Finnish neurosurgical centers in the treatment of 501 consecutive patients with distal anterior cerebral artery (DACA) aneurysms. Our aim was to compare treatment outcomes of these lesions with intracranial aneurysms in general and to identify factors predicting the outcome.

METHODS

We analyzed the clinical and radiological data of all 501 patients and focused on the 427 patients treated between 1980 and 2005, the era of microsurgery and computed tomographic imaging. No patients were lost to follow-up. We compared treatment and outcome of ruptured DACA aneurysms (n = 277) with all consecutive ruptured aneurysms from the Kuopio Cerebral Aneurysm Database (n = 2243) and used multivariate analysis to identify factors predicting 1-year outcome.

RESULTS

DACA aneurysms accounted for 6% of all intracranial aneurysms. They were smaller (median, 6 versus 8 mm), more frequently associated with multiple aneurysms (35 versus 18%), and presented more often with intracerebral hematomas (53 versus 26%) than ruptured aneurysms in general. Their microsurgical treatment showed the same complication rates (treatment morbidity, 15%; treatment mortality, 0.4%) as for other ruptured aneurysms. At 1 year after subarachnoid hemorrhage, they had similar favorable outcome (Glasgow Coma Scale score >or=4) as other ruptured aneurysms (74 versus 69%), but their mortality rate was lower (13 versus 24%). Factors predicting unfavorable outcome for ruptured DACA aneurysms were advanced age, Hunt and Hess grade greater than or equal to III, rebleeding before treatment, intracerebral hematoma, intraventricular hemorrhage, and severe preoperative hydrocephalus.

CONCLUSION

Despite their specific features, with modern treatment methods, ruptured DACA aneurysms have the same favorable outcome and lower mortality at 1 year as ruptured aneurysms in general.

Microneurosurgical management of aneurysms at the A2 segment of anterior cerebral artery (proximal pericallosal artery) and its frontobasal branches

BACKGROUND

Aneurysms originating from the A2 segment of ACA and its frontobasal branches are rare, forming less than 1% of all IAs. There are only few reports on management of A2As. In this article, we review the practical anatomy, preoperative planning, and avoidance of complications in the microsurgical dissection and clipping of A2As.

METHODS

This review, and the whole series on IAs, is mainly based on the personal microneurosurgical experience of the senior author (JH) in two Finnish centers (Helsinki and Kuopio), which serve, without patient selection, the catchment area in Southern and Eastern Finland.

RESULTS

These two centers have treated more than 10000 patients with IAs since 1951. In the Kuopio Cerebral Aneurysm Database of 3005 patients and 4253 IAs, there were 35 patients carrying 35 A2As, forming 1% of all patients with IAs, 0.8% of all IAs, and 3% of all ACA aneurysms. Twenty-one (60%) patients presented with ruptured A2As with ICH in 11 (52%) and IVH in 7 (33%). Nineteen patients (54%) had multiple aneurysms.

CONCLUSIONS

A2As are often small, even when ruptured, with relatively wide base, and they are frequently associated with ICHs of IVHs. Our data suggest that A2As rupture at smaller size than IAs in general. The challenge is to select appropriate approach, locate the aneurysm deep inside the interhemispheric fissure, and to clip the neck adequately without obstructing branching arteries at the base. Unruptured A2As also need microneurosurgical clipping even when they are small.

Endovascular therapy of distal anterior cerebral artery aneurysms-an effective treatment option

BACKGROUND

Surgical treatment of APAs is associated with relatively high morbidity and mortality. The aim of this study was to illustrate the technical achievements of endovascular procedures in the distal anterior cerebral artery area, technical difficulties and how they can be overcome, and the outcome of endovascular treatment of APAs.

METHODS

Between 1997 and 2006, of 49 patients with APAs at our institution, 29 were treated endovascularly (4.1% of all endovascularly treated aneurysms; F:M = 3.8; mean age, 52.8 +/- 11.5 years), and 12 were treated surgically. Twenty-one (72.4%) of the endovascularly treated patients had a subarachnoid hemorrhage. The mean observation period was 25 +/- 22.8 months.

RESULTS

In 27 (93.1%) cases, complete occlusion of the aneurysm was achieved. The intervention led to 5 (17.2%) cases of minor complications with no neurologic deficits: 2 thromboembolisms, 1 local thrombus, 1 occlusion, and 1 recurrent hemorrhage. Mortality related to the intervention was 3.4%. There was no morbidity associated with the elective procedures. The dome-to-neck ratio is the main predictor of reperfusion. The most important factor impairing the outcome in terms of the GOS status is the presence of an intraparenchymal hematoma, followed by thrombembolic complications.

CONCLUSION

Endovascular treatment of APAs is feasible, safe, and effective. Mortality and morbidity are comparable with surgical therapy. An intraparenchymal hematoma has a severe negative influence on the patient's condition after rehabilitation. In these cases, surgical intervention should be considered. In case of incomplete occlusion of the aneurysm, prompt reintervention is required.

Thrombosed giant aneurysm of the pericallosal artery with inconclusive findings of multiple neuroimaging studies

A 65-year-old woman presented with a thrombosed giant pericallosal artery aneurysm manifesting as headache and memory loss that developed over a 2-year period. Computed tomography (CT), magnetic resonance (MR) imaging, and conventional and CT angiography could not establish the differential diagnosis. Open craniotomy revealed the mass as thrombosed giant aneurysm from the pericallosal artery. Direct clipping with thrombectomy was performed successfully with an uneventful postoperative course. Thrombosed giant aneurysm of the distal anterior cerebral artery should be considered in the differential diagnosis of an unusual mass in the mid-frontal area, particularly in the presence of inconclusive angiographic and MR imaging findings.

Surgical experience of the ruptured distal anterior cerebral artery aneurysms

OBJECTIVE

Distal anterior cerebral artery (DACA) aneurysms are fragile and known to have high risks for intraoperative premature rupture and a relatively high associated morbidity. To improve surgical outcomes of DACA aneurysms, we reviewed our surgical strategy and its results postoperatively.

METHODS

A total of 845 patients with ruptured cerebral aneurysms were operated in our hospital from January 1991 to December 2005. Twenty-three of 845 patients had ruptured DACA aneurysms which were operated on according to our surgical strategy. Our surgical strategy was as follows; early surgery, appropriate releasing of CSF, appropriate surgical approach, using neuronavigating system, securing the bridging veins, using temporary clipping and/or tentative clipping, meticulous manipulation of aneurysm, and using micro-Doppler flow probe. Twenty of 23 patients who had complete medical records were studied retrospectively. We observed the postoperative radiographic findings and checked Glasgow Outcome Scale score sixth months after the operation.

RESULTS

Nineteen DACA aneurysms were clipped through a unilateral interhemispheric approach and one DACA aneurysm was clipped through a pterional approach. Postoperative radiographic findings revealed complete clipping of aneurysmal neck without stenosis or occlusion of parent arteries. In two patients, a residual neck of aneurysm was visualized. Seventeen patients showed good recovery, one patient resulted in moderate disability, while 2 patients died.

CONCLUSION

With our surgical strategy it was possible to achieve acceptable surgical morbidity and mortality rates in patients with DACA aneurysms. Appropriate use of tentative clipping, temporary clipping and neuro-navigating systems can give great help for safe approach and clipping of DACA aneurysm.

Rapid regrowth of a successfully coiled traumatic pericallosal aneurysm

Regrowth of an intracranial aneurysm is a known complication of endovascular coiling. We report a patient with a traumatic pericallosal aneurysm which was initially treated successfully with endovascular coiling. Six-month follow-up angiography showed aneurysm regrowth with migration of the coils. To our knowledge, recurrence of a coiled pericallosal aneurysm of traumatic etiology has not been previously reported. Endovascular coiling may not be the best primary treatment for traumatic pericallosal artery aneurysms.

ANEURYSMS OF THE DISTAL ANTERIORCEREBRAL ARTERY

OBJECTIVE

The aim of this study was to present the clinical and radiological characteristics, surgical management, and outcome in a large series of patients with aneurysms of the distal anterior cerebral artery (DACA) managed in the microsurgical era.

METHODS

The records of 1109 patients with anterior circulation aneurysms managed at the authors' institution between 1970 and 1998 were reviewed.

RESULTS

Fifty-nine patients (5.3%) were identified with 67 DACA aneurysms. Seventy-three percent of the patients were women. The mean age of all patients was 47 years. Multiple aneurysms were identified in 51% of all patients, most commonly on the middle cerebral artery. Thirty-six patients had ruptured DACA aneurysms and 23 had unruptured aneurysms. In those with ruptured aneurysms, the admission grade was Grade I in 10 patients (27.8%), Grade II in three patients (8.3%), Grade III in 10 patients (27.8%), Grade IV in seven patients (19.4%), and Grade V in six patients (16.7%). Frontal lobe hematomas occurred in 28% of the patients with ruptured aneurysms and carried a poor prognosis. In those with unruptured aneurysms, 11 were incidental and 12 were identified after a subarachnoid hemorrhage from another aneurysm. The mean diameter was 10 mm in ruptured aneurysms and 5.8 mm in unruptured aneurysms. Fifty-eight patients underwent surgery and one patient was treated with endovascular coiling. Six patients, all with ruptured aneurysms, died. Seventy percent of survivors with ruptured aneurysms had a favorable outcome.

CONCLUSION

DACA aneurysms possess a number of characteristics that distinguish them from the more common intracranial aneurysms. With modern neurosurgical and endovascular techniques, an acceptable operative morbidity and mortality can be achieved.

Distal Anterior Cerebral Artery Mirror Aneurysms and Middle Cerebral Artery Aneurysms-Case Report-

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.

Distal Anterior Cerebral Artery Aneurysms-Report of 26 Cases-

Distal anterior cerebral artery (ACA) aneurysms are rare, and constitute approximately 1.5% to 9% of all intracranial aneurysms. They show some unique features compared with other aneurysms in the cerebral circulation and are frequently treated with a different technique. Twenty-six of 364 patients with cerebral aneurysms treated at our department between 1996 and 2004 had distal ACA aneurysms (7.1%). Twenty-three of the 26 patients were treated through an anterior interhemispheric approach and two with a pterional approach. All saccular aneurysms were successfully clipped except one which was embolized after the surgery. The only fusiform aneurysm spontaneously thrombosed and resolved with parent artery occlusion. Two of the 26 patients had multiple aneurysms. The surgical mortality was 8%. Distal ACA aneurysms have higher mortality and morbidity than other anterior circulation aneurysms. They should be aggressively treated even if very small because of the tendency to rupture. Endovascular treatment is an alternative in the management of these aneurysms. The most important factors affecting the outcome are grade on admission and the neurosurgeon's experience.

Giant aneurysm of the azygos pericallosal artery: case report and review of the literature

BACKGROUND

Pericallosal aneurysms are encountered less than 6.7%, and giant aneurysms among them even less. Giant azygos pericallosal artery aneurysm at the callosomarginal bifurcation is extremely rare, and our case presented herein is the second one. The case is discussed with thorough review of the literature.

METHODS

A 65-year-old woman presented with an extremely rare giant aneurysm on the azygos pericallosal artery manifesting as subarachnoid hemorrhage in World Federation of Neurosurgical Societies Grade 3. Computed tomography (CT), magnetic resonance angiography (MRA), and four vessel angiography revealed a giant azygos pericallosal artery aneurysm associated with a second aneurysm at the left M1.

RESULTS

After recovery to Grade 2, she underwent surgery via the right frontal interhemispheric approach for the azygos artery aneurysm on the 17th day after bleeding. The true dimensions of the aneurysm were greater than indicated by angiography because of partial thrombosis. Trilobulate aneurysm was carefully dissected from the surrounding structures. Postoperative cerebral angiography showed no filling of the clipped aneurysm and preservation of circulation.

CONCLUSIONS

The treatment of distal anterior cerebral artery aneurysms is often difficult, because of their broad-based irregular configurations and adherence to surrounding tissue, tendency to bleed irrespective of size and the coexistence of other cerebral aneurysms. However, excellent outcomes can be obtained based on thorough preoperative radiologic evaluation, including magnetic resonance imaging (MRI), and correct selection of surgical approach.

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.

Distal anterior cerebral artery aneurysms

BACKGROUND

The incidence of saccular aneurysms in the distal anterior cerebral artery (DACA aneurysms), also called pericallosal or A2 aneurysms, has been estimated to be from 1.5 to 9.0% of all intracranial aneurysms in large series in the literature [5,10,12,18]. All reported series of DACA aneurysms have shown a high association with intracranial aneurysms in other locations. These aneurysms are fragile, frequently rupture prematurely during exposure, and have a higher morbidity than expected from their angiographic appearance and location.

METHODS

A total of 1,350 patients with cerebral aneurysms were operated in the Department of Neurosurgery at Santa Casa Hospital in Belo Horizonte from January 1982 to January 1998. Seventy-two of those 1,350 patients had DACA aneurysms (5.3%), 51 female and 21 male. The age ranged from 26 to 69 years, the mean age being 44 years. This group of patients is reported herein. We propose three different approaches to DACA aneurysms depending on their location, all of them performed through a unilateral triangular bone flap that can then vary from fronto-basal to parietal.

RESULTS

There was no mortality among patients with a single DACA aneurysm. Five deaths in this series were cases of multiple aneurysms. In patients with preoperative Hunt and Kosnick grades I and II [9], we had 90% good results. In grade III patients, we achieved 68.4% good results. The only grade IV patient had a full recovery. All 74 DACA aneurysms in the 72 operated patients were completely clipped, including two giant aneurysms.

CONCLUSION

DACA aneurysms have higher morbidity and mortality rates when compared to other supratentorial aneurysms. We recommend the use of a unilateral interhemispheric approach as the most appropriate for aneurysms in this location. In cases of patients with multiple aneurysms who require two different craniotomies, we propose two surgical stages, starting with the aneurysm that has bled. A high mortality rate was noted when two craniotomies were performed in the same sitting.

Aneurysms of the distal anterior cerebral artery: report of 14 cases and a review of the literature

BACKGROUND

Distal anterior cerebral artery aneurysms are rare and compose about 4.5% of all intracranial aneurysms. They generally arise at the bifurcation of the pericallosal and callosomarginal arteries. Their surgical approach is different from those of other anterior circulation aneurysms. These aneurysms present some special difficulties for neurosurgeons, including narrow exposure in the interhemispheric fissure, dense adhesions between the cingulate gyri, difficulty in controlling the parent artery, and the association of multiple aneurysms and vascular anomalies.

METHODS

Between January 1975 and May 1996, 14 cases of saccular aneurysms of the distal anterior cerebral artery were operated at the University of Hacettepe. The clinical presentations, neuroradiological findings, and operative approaches of these aneurysms were analyzed. In addition, the clinical series and isolated case reports in the English literature were also extensively reviewed.

RESULTS

The incidence of the aneurysms in this location was 2.8% of a total of 494 surgically treated cases in our center. Of 14 patients, eight were women and six were men. Multiple aneurysms were found in five patients (35%). All patients were operated via the interhemispheric route. Thirteen patients had good outcome and one patient died.

CONCLUSIONS

We believe that all difficulties related to distal anterior cerebral artery aneurysms can be minimized with sufficient knowledge of microsurgery and surgical anatomy, using microtechniques and experience.

Outcome in 43 patients with distal anterior cerebral artery aneurysms

BACKGROUND AND PURPOSE

The aim of this retrospective multicenter study was to evaluate the outcome of distal anterior cerebral artery (DACA) aneurysms and to determine the incidence, causes, and consequences of unfavorable outcomes.

METHODS

43 patients with 50 DACA aneurysms (27 females and 16 males, mean age 49 years) were studied retrospectively. Forty-four DACA aneurysms were treated surgically (83% with an interhemispheric approach), and 2 were embolized. At postoperative day 10, all patients underwent routine angiography. The outcome at 6 to 12 months was scored according to the Glasgow Outcome Scale (GOS).

RESULTS

35 DACA aneurysms were ruptured. Among the 26 "good"-grade patients (Hunt and Hess grades I through III), 18 (69.2%) were in GOS 1, 2 in GOS 2 (7.7%), 2 in GOS 3 (7.7%), and 4 in GOS 5 (15.4%); among the 9 "poor"-grade patients (Hunt and Hess grades IV and V), 1 (11.1%) was in GOS 1, 2 in GOS 2 (22.2%), 2 in GOS 3 (22.2%), and 4 in GOS 5 (44.5%). The initial intracerebral hemorrhage (ICH) (40%) induced neurological aftereffects in 8 patients. An operative rupture occurred in 40%, with a temporary occlusion in 28.6% that was responsible for mediocre results in 3 patients (8.7%). A postoperative thrombosis was observed in 4 patients (11.4%) and an aneurysmal remnant in 1 (2.8%). Ten DACA unruptured aneurysms were clipped without operative rupture or thrombosis.

CONCLUSIONS

The authors suggest that the proportion of ruptured DACA aneurysms evolving to a GOS 1 or 2 was similar to that of aneurysms found in other locations, after early surgery. Endovascular treatment should be considered in the management of uncommon ruptured fusiform DACA aneurysms.

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.