Microneurosurgical Management of Anterior Choroid Artery Aneurysms

Comparison between ruptured anterior choroidal artery aneurysms and ruptured intracranial aneurysms in other locations in relation to aneurysm dimensions at rupture

PURPOSE

It was noticed that anterior choroidal artery (AChoA) aneurysms appear to rupture at relatively smaller sizes compared with aneurysms in other intracranial locations, based on anecdotal clinical experience. We therefore aimed to compare ruptured AChoA aneurysms with other ruptured aneurysms in other intracranial locations, pertaining to aneurysm dimensions. This may help in finding out if the rupture risk stratification, based on the amalgamation of aneurysms of multiple locations in one group, precisely estimates aneurysm rupture risk.

METHODS

255 ruptured intracranial aneurysms, which underwent assessment with catheter angiography with 3D reconstruction, in a single tertiary center between January 2000 and December 2023, were included. 6 aneurysm dimensions were compared.

RESULTS

Statistically significant larger aneurysm maximum diameter, height, width and size ratio (SR) of the ruptured posterior communicating artery (PCOMM) aneurysms were identified when compared with ruptured AChoA aneurysms. No statistically significant difference in the aneurysm maximum diameter, height and width between the ruptured AChoA and ruptured anterior cerebral artery (ACA), anterior communicating artery (Acom), pericallosal artery and basilar tip aneurysms was found. AChoA aneurysms appear to rupture at a relatively small size, which is comparable to other aneurysm locations that are often grouped into different categories in rupture risk stratification.

CONCLUSION

More detailed location-specific rupture risk estimation may be needed. The combination of multiple intracranial aneurysm locations into a single category for risk stratification may not reflect the true aneurysm size at rupture for some aneurysms.

Management of Anterior Choroidal Artery Aneurysms: A Retrospective Cohort Study

Background: Anterior choroidal artery (AChoA) aneurysms pose a challenge for both endovascular and clipping procedures. The eloquent territory supplied by the parent vessel has limited collateralization and its compromise can lead to significant morbidity. This study aims to analyze the clinical outcomes and procedure-related complications of clipping and endovascular treatment of AChoA aneurysms to aid physician decision making. Methods: Thirty-two ruptured and unruptured AChoA aneurysms that underwent catheter angiography at a single neurovascular center between January 2000 and December 2023 were included. Either conservative management, clipping, and/or endovascular treatment were performed. Clinical outcomes and complications were analyzed retrospectively. Results: Twenty-four endovascular treatments and seven clipping procedures were included. Of the total 24 endovascular procedures, 46% were primary coiling, 25% were balloon-assisted coiling, 13% were flow diverting stent, 8% were combined balloon-assisted coiling and flow diverting stent, and 8% were combined balloon-assisted and stent-assisted coiling. There was no procedure-related mortality in both groups. No intra- or post-procedural ruptures/re-ruptures occurred during follow-up in both endovascular and clipping cohorts. AChoA territory infarcts occurred in 4% of the endovascular and 29% of the clipping cohorts. Other thromboembolic complications occurred in 4% of the endovascular cohort. The recurrence rate requiring retreatment was 12.5% for the endovascular and 43% for the clipping cohort. A favorable clinical outcome (mRS ≤ 2) was 78% for the endovascular cohort and 67% for the clipping cohort. Conclusions: Endovascular and clipping outcomes align with prior studies, with endovascular showing a favorable safety profile. Both approaches are viable, though they present distinct risks and advantages.

Comparison of outcomes between clipping and endovascular coiling in anterior choroidal artery aneurysm: a systematic review

SAH (subarachnoid hemorrhage) caused by aneurysm rupture has the greatest mortality rate, with nearly 50% of patients unable to survive beyond 1 month after the attack. Anterior choroidal artery (AChA) aneurysms are one of the most difficult to treat among the numerous types of aneurysms. Until now, some neurosurgeons employed shearing while others employed coiling. In this trial, researchers will compare surgical clipping and endovascular coiling treatments for anterior choroidal artery aneurysms in terms of mortality, rebleeding, retreatment, and post-procedure outcomes. Using the PubMed electronic database, the Cochrane library, the Medline Database, the Directory of Open Access Journals, and EBSCHOHOST, a systematic review compared surgical clipping and endovascular coiling in all cases of choroidal artery aneurysm. There were 17 studies that met the eligibility requirements, with a total of 1486 patients divided into groups that underwent clipping (1106) or endovascular coiling (380). The mortality rate for clipping is 1.8%, while the mortality rate for endovascular coiling is 2.34%. Rebleeding occurs in 0% of patients undergoing endovascular coiling and 0.73% of patients undergoing clipping. Retreatment of clipping was 0.27%, while endovascular coiling was 3.42%. Post-complication procedures occurred in 11.12% of patients undergoing endovascular clipping and 15.78% of patients undergoing endovascular coiling. The intervention technique of clipping has a reduced rate of mortality, reoperation, and post-operative complications. Endovascular coiling results in a reduced rate of rebleeding than clipping.

A case of anterior choroidal artery occlusion test under MEP monitoring for a recurrent internal carotid artery-anterior choroidal artery bifurcation aneurysm clipping

A 59-year-old female with recurrent Anterior Choroidal Artery (AchA) aneurysm was elected for surgery at our institution through a standard pterional approach. Two thin perforating branches were found to origin from the dome of the aneurysm during operation, and therefore complete aneurysm clipping preserving these branches was not feasible. These perforating branches were temporarily occluded under motor-evoked potential (MEP) monitoring. The MEPs remained stable during 10 min of temporary clipping, and we concluded that these branches could be sacrificed, and therefore neck clipping was performed occluding these tiny AchA perforators. Although postoperative magnetic resonance imaging with diffusion-weighted images showed ischemic signs in left AchA territory after the operation, the patient remained asymptomatic and was discharged home with mRS 0.

Factors affecting global neurocognitive status and frontal executive functions in the early stage after surgical clipping of unruptured anterior circulation aneurysms with respect to keyhole clipping and conventional clipping

PURPOSE

This study investigated the most significant factor for the preservation of the global neurocognitive status and frontal executive functions in the surgical clipping of unruptured anterior circulation aneurysms, specifically in keyhole and conventional clipping procedures.

METHODS

The prospective study that was performed to examine the effects of aneurysm surgery on the patient's global neurocognitive status and frontal executive functions started on April 2016. After exclusion posterior circulation aneurysms, anterior communicating aneurysms treated by interhemispheric approach, giant aneurysms, and paraclinoid aneurysms, 23 patients who were enrolled before May 2017 were treated by conventional clipping, and 18 patients who were enrolled after June 2017 were treated by keyhole clipping. Two patients were excluded from each group due to missing data. Finally, 21 and 16 patients in each group were analyzed, respectively. Three-tesla magnetic resonance imaging was performed before and after surgery to detect the presence of perioperative cerebral infarctions and brain edema. The Mini-Mental State Examination, Frontal Assessment Battery, and Self-Rating Depression Scale scores were obtained before and 1 month after surgery.

RESULTS

Logistic regression analyses indicated that anterior communicating and internal carotid artery aneurysms were the most significant factors for poor outcomes and that keyhole clipping for these two types of aneurysm was the most significant factor for the preservation of patient global neurocognitive status. Keyhole clipping was also the most significant factor for the preservation of frontal executive functions in patients.

CONCLUSIONS

Keyhole clipping may be more favorable than conventional clipping for the preservation of the global neurocognitive status and frontal executive functions. Moreover, it may be the most effective factor for preservation of global neurocognitive status when it is indicated for anterior communicating or internal carotid artery aneurysms.

An anomalous hyperplastic anterior choroidal artery associated with an unruptured internal carotid–posterior communicating artery aneurysm

The anterior choroidal artery (AChA) injuries can result in severe neurologic deficits, so requiring careful observation to avoid inadvertent damage during neuroendovascular procedures. In this case report, we present the unusual case of an anomalous hyperplastic AChA associated with a fetal-type posterior communicating artery (PCoA), and an unruptured internal carotid artery (ICA) –PCoA aneurysm. A 54-year-old woman presented with persistent headache. Brain magnetic resonance imaging (MRI) showed an unruptured cerebral aneurysm in the right ICA, and cerebral angiography revealed a proximal fetal-type PComA and a distal anomalous hyperplastic AChA. Coil embolization was performed with no neurologic deficits and the target lesion was embolized with a total of 6 coils. An anomalous hyperplastic AchA has a lengthy course with numerous choroidal and perforating branches, and therefore, an abundant perfusion region. Thorough knowledge of the development and anatomy of anomalous arteries is important for safely performing endovascular procedures without causing any ischemic complications.

Multiple anterior choroidal arteries and perioperative ischemic complications in unruptured anterior choroidal artery aneurysms treated with microsurgical clipping

BACKGROUND

This study aimed to identify the association between the number of anterior choroidal arteries (AchoAs) and procedure-related ischemic complications in microsurgical clipping of unruptured AchoA aneurysms.

METHODS

We retrospectively reviewed the clinical, radiological, and intraoperative findings of 153 patients with unruptured AchoA aneurysms treated with microsurgical clipping between January 2012 and November 2020 in a single tertiary institution. Intraoperative video clips were reviewed, and the AchoA type was categorized into two according to the number of AchoAs: (1) single-type group with single origin and single branch and (2) multiple-type group with duplicated origin or divided multiple branches. Uni- and multivariate analyses were performed to assess the relationship between clinical and radiological factors and perioperative ischemic complications.

RESULTS

Of the 153 patients, 52 (34%) were categorized as multiple-type group. The frequency of perioperative ischemic complications, including decreased intraoperative motor evoked potential (MEP), silent infarction, and postoperative ischemic symptoms, was significantly higher in the multiple-type group than in the single-type group (13 [25%] vs 6 [5.9%], p = 0.001). Multivariate logistic regression analysis showed that multiple-type group (odds ratio [OR], 3.725; 95% confidence interval [CI], 1.171-11.845, p = 0.026) and multilobulated shape (OR, 9.512; 95% CI, 2.093-43.224; p = 0.004) were significantly associated with perioperative ischemic complications. Among 9 patients with decreased MEP, postoperative ischemic symptoms developed in 2 patients after clip adjustment.

CONCLUSIONS

Multiple-type AchoA aneurysms and multilobulated shape are significantly correlated with perioperative ischemic complications. Postoperative ischemic complications can be minimized by recognizing these variations and using multimodal approach with MEP monitoring.

Microsurgical Treatment of 86 Anterior Choroidal Artery Aneurysms: Analysis of Factors Influencing the Prognosis

PURPOSE

 To explore factors affecting the prognosis of choroidal anterior artery aneurysm (AChAA) and provide a reference for improving the postoperative outcome.

METHODS

 The clinical data of 86 patients with AChAA who underwent treatment by a single surgeon were collected and analyzed retrospectively. Univariate analysis and multivariate logistic regression analysis were conducted to examine 12 factors that possibly affected outcome.

RESULTS

 The five factors that affected the patient outcomes were times of subarachnoid hemorrhage (SAH), characteristics of SAH on computed tomography (CT), Hunt-Hess grade, aneurysm size, and presence or absence of postoperative complications. Characteristics of SAH on CT (odds ratio [OR]: 3.727; p = 0.000; 95% confidence interval [CI], 1.850-7.508), aneurysm size (OR: 6.335; p = 0.000; 95% CI, 2.564-15.647), and presence or absence of postoperative complications (OR: 4.141; p = 0.000; 95% CI, 1.995-8.599) were independent risk factors influencing the prognosis. In addition, the incidence of postoperative ischemia (caused by anterior choroidal artery syndrome) is related to the aneurysm emitting part and presence or absence of intraoperative rupture.

CONCLUSIONS

 The analysis of characteristics of SAH on CT, aneurysm size, and presence or absence of postoperative complications can roughly determine the outcome of patients with AChAAs.

A Case of Subarachnoid Hemorrhage with Dissecting Aneurysm of the Anterior Choroidal Artery

Objective

Dissecting aneurysms of the anterior choroidal artery (AchoA) are extremely rare, with only a few reported cases. Herein, we report an extremely rare case of subarachnoid hemorrhage with dissecting aneurysm of the AchoA.

Case Presentation

A 68-year-old man was hospitalized for sudden onset of headache, progressive consciousness disorder, and right hemiparesis. He had a prior medical history of systemic lupus erythematosus (SLE), and was taking prednisolone (50 mg/day) for 15 months. CT showed subarachnoid hemorrhage in the left side of the basal cistern and Sylvian fissure. Left internal carotid artery (ICA) angiography revealed a fusiform aneurysm of the AchoA. He was diagnosed with a ruptured dissecting aneurysm of the AchoA because the shape of aneurysm was fusiform and there was laminar flow inside the aneurysm. Parent artery occlusion (PAO) was performed to prevent re-hemorrhage on the day of onset. Although ventricular drainage for acute hydrocephalus was performed after AchoA occlusion, his consciousness disorder did not improve. Postoperative angiography at 1-week recovery from the procedure revealed disappearance of the AchoA, including the dissecting aneurysm. However, he died following septic shock caused by pneumonia at 1 month after the procedure.

Conclusion

We report an extremely rare case of subarachnoid hemorrhage with a dissecting aneurysm of the AchoA. Vasculitis caused by SLE and a vulnerability of the vessel wall following chronic steroid use are potential causes of the dissecting aneurysm of the AchoA.

Potential Risks and Limited Indications of the Supraorbital Keyhole Approach for Clipping Internal Carotid Artery Aneurysms

Background

Internal carotid artery (ICA) aneurysm may be a good target for supraorbital keyhole clipping. We discuss the surgical indications and risks of keyhole clipping for ICA aneurysms based on long-term clinical and radiologic results.

Methods

This was a retrospective analysis of 51 patients (aged 35–75 years, mean 62 years) with ICA aneurysms (mean 5.8 ± 1.8 mm) who underwent clipping via the supraorbital keyhole approach between 2005 and 2017. Neurologic and cognitive functions were examined by several methods, including the modified Rankin Scale and Mini-Mental Status Examination. The state of clipping was assessed 1 year and then every few years after the operation.

Results

Complete clipping was confirmed in 45 patients (88.2%), dog-ear remnants behind the clip persisted in 4 patients, and wrapping was performed in 2 patients. Mean duration of postoperative hospitalization was 3.4 ± 6.9 days. The mean clinical follow-up period was 6.6 ± 3.2 years. The overall mortality was 0, and overall morbidity (modified Rankin Scale score ≥2 or Mini-Mental Status Examination <24) was 3.9%. Completely clipped aneurysms did not show any recurrence during the mean follow-up period of 6.3 ± 3.1 years, but the 2 (3.9%) aneurysms with neck remnants showed regrowth.

Conclusions

The risk of neck remnant behind the clip blade is a drawback of supraorbital keyhole clipping. The surgical indication requires preoperative simulation and careful checking of the clip blade state is essential.

Microsurgical Clipping of Anterior Choroidal Artery Aneurysms: A Systematic Approach to Reducing Ischemic Complications in an Experience with 146 Patients

BACKGROUND

Aneurysms of the anterior choroidal artery (AChA) have been associated with high treatment-associated morbidity due to ischemic complications.

OBJECTIVE

To report a large clinical experience of microsurgically treated AChA aneurysms and describe a systematic approach to reduce ischemic complications.

METHODS

One hundred forty-six patients with AChA aneurysms were retrospectively reviewed from a prospectively maintained database. Clinical characteristics, surgical techniques, clinical outcomes, arterial infarction, and use of intraoperative adjuncts (ie, ultrasonography, indocyanine green videoangiography, and neuromonitoring) were analyzed.

RESULTS

In total, one hundred forty-three aneurysms (97.9%) were clipped. Temporary clipping was utilized in 47 cases (32.2%) with mean occlusion time of 5.6 min. Arterial infarction occurred in 12 patients (8.2%). In clipped aneurysms, 90.5% were completely obliterated, 8.8% had minimal residual (<5% of original), and 0.7% were incompletely occluded (>5% of original). Mortality (2.7%) was limited to patients with high-grade subarachnoid hemorrhage. Indocyanine green videoangiography and neuromonitoring altered operative technique in ∼20% of cases. Multivariate logistic regression identified intraoperative rupture as the sole predictor for arterial infarction.

CONCLUSION

Open microsurgical clipping remains a safe, effective treatment for AChA aneurysms. Microsurgical technique is paramount in preserving AChA patency and reducing ischemic complications. Despite increasing reliance on qualitative measures of AChA blood flow (videoangiography and ultrasonography) and neurophysiological monitoring, these technologies aid us infrequently. However, these adjuncts provide important safety checks for AChA patency. Temporary clipping must be used judiciously to lower the risk of intraoperative rupture while limiting possible ischemia in the AChA territory.

Microsurgical Treatment of Unruptured Anterior Choroidal Artery Aneurysms: Incidence of and Risk Factors for Procedure-Related Complications

OBJECTIVE

To describe our experiences with microsurgical treatment of unruptured anterior choroidal artery (AchA) aneurysms, and to evaluate the incidence of and risk factors for procedure-related complications.

METHODS

The study included 110 patients treated between January 2012 and December 2016. All patients met the following criteria: 1) microsurgical treatment of an unruptured AchA aneurysm was performed; and 2) clinical and radiographic follow-up data were available, including findings from preoperative digital subtraction angiography. The incidence of and risk factors for procedure-related complications were retrospectively evaluated. The χ² test and Mann-Whitney U test were used in statistical analysis, and univariate analysis and multivariate logistic regression analysis were conducted.

RESULTS

Procedure-related complications occurred in 5 patients (4.5%), including symptomatic complications in 4 patients (3.6%) and asymptomatic complications in 1 patient (0.9%). Multivariate logistic regression analysis indicated that the angle between the vertical line to the cranial base and the axis of the communicating segment of the internal carotid artery (MiC angle) (odds ratio [OR], 1.66; 95% confidence interval [CI], 1.13-5.26; P = 0.038) and the angle between the projection line of the aneurysmal dome and the axis of the communicating segment of the internal carotid artery (DC angle) (OR, 3.82; 95% CI, 1.49-11.7; P = 0.014) were independent risk factors for procedure-related complications.

CONCLUSIONS

When microsurgical treatment of unruptured AchA aneurysms was performed, the procedure-related complication rate was 4.5%. Patients with AchA aneurysms with a smaller MiC angle and smaller DC angle may be at a higher risk of procedure-related complications when undergoing microsurgical treatment.

Clinical importance of the anterior choroidal artery: a review of the literature

The anterior choroidal artery (AChA) is a critical artery in brain physiology and function. The AChA is involved in many diseases, including aneurysm, brain infarct, Moyamoya disease (MMD), brain tumor, arteriovenous malformation (AVM), etc. The AChA is vulnerable to damage during the treatment of these diseases and is thus a very important vessel. However, a comprehensive systematic review of the importance of the AChA is currently lacking. In this study, we used the PUBMED database to perform a literature review of the AChA to increase our understanding of its role in neurophysiology. Although the AChA is a small thin artery, it supplies an extremely important region of the brain. The AChA consists of cisternal and plexal segments, and the point of entry into the choroidal plexus is known as the plexal point. During treatment for aneurysms, tumors, AVM or AVF, the AChA cisternal segments should be preserved as a pathway to prevent the infarction of the AChA target region in the brain. In MMD, a dilated AChA provides collateral flow for posterior circulation. In brain infarcts, rapid treatment is necessary to prevent brain damage. In Parkinson disease (PD), the role of the AChA is unclear. In trauma, the AChA can tear and result in intracranial hematoma. In addition, both chronic and non-chronic branch vessel occlusions in the AChA are clinically silent and should not deter aneurysm treatment with flow diversion. Based on the data available, the AChA is a highly essential vessel.

Flow diversion for anterior choroidal artery (AChA) aneurysms: a multi-institutional experience

BACKGROUND

Anterior choroidal artery (AChA) aneurysms represent a small subset of cerebral aneurysms. The Pipeline Embolization Device (PED) has been successfully applied to various aneurysms of the supraclinoid internal carotid artery (ICA). The treatment of these aneurysms requires special attention due to the eloquent territory supplied by the AChA. We report the largest and first dedicated series of flow diversion treatment of AChA aneurysms.

METHODS

Four institutional neurointerventional databases were reviewed for cases of intracranial aneurysms treated with PED. Patient and aneurysm data as well as angiographic imaging were reviewed for all cases of AChA aneurysms treated with PED. AChA aneurysms were defined as aneurysms distal to the AChA and proximal to the ICA terminus, with or without the incorporation of the AChA.

RESULTS

Eighteen AChA aneurysms were treated during the study period. All aneurysms were successfully treated with a mean follow-up of 19.1 months. The large majority of aneurysms (15/18, 83.3%) were completely obliterated. No patients suffered from intra- or post-procedural complications. A1 stenosis was a common occurrence, seen in 10 of 16 (62.5%) covered anterior cerebral arteries (ACAs), although all were asymptomatic. All AChAs remained patent at last follow-up.

CONCLUSIONS

The PED can be used successfully in AChA aneurysms with a good safety and efficacy profile. All AChAs remained patent. Collateral flow networks, especially for the ACA, affect long-term branch vessel patency. Treatment with PED for AChA aneurysms appears to be a reasonable option to consider and should be evaluated in a larger cohort.

Complication Risk Factors in Anterior Choroidal Artery Aneurysm Treatment

OBJECT

The anterior choroidal artery (AChoA) is a rare location for intracranial aneurysms. The treatment of these aneurysms may be challenging due to the risk of occlusion of such a small and eloquent artery as the AChoA. We aimed to evaluate the risk factors for complications in AChoA aneurysm treatment.

METHODS

We retrospectively analyzed 47 consecutive AChoA aneurysms in 40 patients treated in our institution from 1999 and 2014 by endovascular means (87%) or surgical clipping (13%). Minor (transient or minor neurological deficits) and major complications (severe permanent neurological deficits or death) were systematically recorded. The influence of patient age, sex, aneurysm size, neck size, shape, dome-to-neck ratio and treatment technique on the occurrence of procedure-related complications was evaluated.

RESULTS

Of the patients 11 experienced procedure-related complications (5 major, 6 minor). Aneurysms with multilobed shape were significantly associated with a higher procedure-related complication rate. There was a tendency for higher major procedure-related complication rate in small volume aneurysms. We did not find any association between the other factors analyzed and occurrence of procedure-related complications.

CONCLUSION

Treatment of AChoA aneurysms has an acceptable complication risk. We did not find any significant differences between surgical and endovascular treatment in terms of procedure-related complication rates. Multilobed aneurysms were significantly associated with a higher procedure-related complication rate.

Comparative outcome analysis of anterior choroidal artery aneurysms treated with endovascular coiling or surgical clipping

Background:

Treatment of anterior choroidal artery (AChA) aneurysms with endovascular coiling or surgical clipping may increase the risk of ischemic complications owing to the critical territory supplied by the AChA. We analyzed the surgical results of endovascular coiling and surgical clipping for AChA aneurysms performed in a single institution, as well as the role of indocyanine green-videoangiography (ICG-VAG) and motor-evoked potential (MEP).

Methods:

We analyzed 50 patients (51 aneurysms; 21 men, 29 women; mean age: 58 years) including 25 with subarachnoid hemorrhage treated with endovascular coiling or surgical clipping between April 1990 and October 2013. The complication rates and clinical outcomes of the coil group (mean follow-up: 61 months) and the clip group (mean follow-up: 121 months) were analyzed with a modified Rankin scale.

Results:

The overall clinical outcome of the coil group (95%) was better than that of the clip group (85%). Especially, the outcomes in the coil group were better in the first investigated period (1990–2007) (P < 0.05). However, after the introduction of ICG-VAG and MEP, the outcomes in the clip group improved significantly (P = 0.005), and treatment-related complications decreased from 20 to 4.7%. Eleven aneurysms (coil group: 8, clip group: 3) showed small neck remnants but no remarkable regrowth, except for 1 case during the mean follow-up period of 91 months.

Conclusions:

Surgical clipping of AChA aneurysms has become safer because of ICG-VAG and MEP monitoring. Coiling and clipping of AChA aneurysms showed good and comparable outcomes with these monitoring methods.

A new endovascular technique for small anterior choroidal artery aneurysms. A consecutive series using the 3-catheter-protective technique

INTRODUCTION

Endovascular treatment of small anterior choroidal artery (AChA) aneurysms can be challenging, especially if the AChA arises from the sac. Preserving its patency during embolization is as important as obliterating the aneurysm. We describe a variant of the "protective microcatheter technique" (PMT) in a series of six patients with AChA aneurysms where the AChA emerged from the sac.

METHODS

Three different microcatheters (KT) were used. The first microcatheter was placed in the AChA to protect it. A remodeling balloon-catheter was then positioned in the internal carotid artery to stabilize the coils during embolization and to control a potential rupture. The third microcatheter was finally used to coil the aneurysm.

RESULTS

Mean sac size of anterior choroidal artery aneurysms was 2×2×2mm. All aneurysms were successfully occluded. There was neither ischemic complication nor ruptured aneurysm during endovascular treatment. A final angiogram demonstrated AChA patency in all cases.

CONCLUSION

The 3KT-PMT for AChA aneurysms appears to be safe and effective to prevent AChA occlusion during aneurysm coiling, especially when the AChA arises from the sac.

Ruptured True Anterior Choroidal Artery Aneurysm in Cisternal Segment

BACKGROUND

Rupture of a true anterior choroidal artery (AChA) aneurysm in the cisternal segment is extremely rare, whereas cases of a distal AChA aneurysm associated with moyamoya disease are increasingly reported.

CASE DESCRIPTION

A 58-year-old woman presented with a severe headache and vomiting. Computed tomography demonstrated a subarachnoid hemorrhage without intraventricular or intracerebral hemorrhaging. Cerebral angiogram findings revealed a proximal AChA aneurysm mimicking an internal carotid artery aneurysm at the origin of the AChA. Intraoperative findings demonstrated a ruptured aneurysm located on a bend of the proximal AChA in the carotid cistern. Neck clipping of the aneurysm with preservation of the AChA led to a good outcome.

CONCLUSIONS

A rare case of ruptured true AChA aneurysm in the cisternal segment, unrelated to moyamoya disease, is presented as a cause of subarachnoid hemorrhage.

Microsurgical anatomy of the cisternal anterior choroidal artery with special emphasis on the preoptic and postoptic subdivisions

Object

The object of this study was to delineate the microsurgical anatomy of the cisternal segment of the anterior choroidal artery (AChA). The authors also propose a new classification of this segment on the basis of its complicated course within the carotid and crural cisterns in relation to important neurovascular structures, and the site of origin, course, and areas of supply of perforating arteries.

Methods

Thirty cadaveric cerebral hemispheres injected with colored latex were dissected under surgical magnification to view the cisternal segment of the AChA and its perforators. Fiber dissections using the Klingler technique were performed in two additional latex injected hemispheres to follow the penetration points, courses, and terminal areas of supply of perforating branches that arise from the cisternal segment of the AChA.

Results

The cisternal segment of the AChA was divided into pre- and postoptic parts that meet at the artery's genu, the most medial extension point of the cisternal segment where the artery makes an abrupt turn after passing under the optic tract. The preoptic part of the AChA extended from its origin at the inferomedial side of the internal carotid artery to the artery's genu, which is commonly located just inferomedial to the initial part of the optic tract. The postoptic part coursed within the crural cistern and extended from the genu to the inferior choroidal point. The genu of the AChA was 8 mm medial to the artery's origin and was located medial to the optic tract in 13% of the hemispheres. The postoptic part was longer than the preoptic part in all hemispheres and had more perforating arteries supplying critical deep structures (preoptic 3.4 per hemisphere vs postoptic 4.6 per hemisphere), and these results were statistically significant (p = 0.01). At the preoptic part, perforating arteries arose from the superolateral portion of the artery and coursed laterally; at the postoptic part, perforators arose from the inferomedial portion of the artery and coursed medially. Perforating arteries from both segments passed most commonly to the optic tract, followed by the anterior segment and apex of uncus in the preoptic part and the cerebral peduncle in the postoptic part.

Conclusions

Both parts of the cisternal segment of the AChA come into surgical view during surgeries for different pathologies in and around the perimesencephalic cisterns. However, attending to the artery's genu and defining pre- and postoptic parts during surgery may help the surgeon locate the origin and eventual course of these perforators, and even estimate the terminal areas of supply of most of the perforating arteries. The proposed classification system can prove helpful in planning any operative procedure along the crural cistern and may reduce the probability of inadvertent injury to perforating branches of the cisternal segment.

Suggested connections between risk factors of intracranial aneurysms: a review

The purpose of this article is to review studies of aneurysm risk factors and the suggested hypotheses that connect the different risk factors and the underlying mechanisms governing the aneurysm natural history. The result of this work suggests that at the center of aneurysm evolution there is a cycle of wall degeneration and weakening in response to changing hemodynamic loading and biomechanic stress. This progressive wall degradation drives the geometrical evolution of the aneurysm until it stabilizes or ruptures. Risk factors such as location, genetics, smoking, co-morbidities, and hypertension seem to affect different components of this cycle. However, details of these interactions or their relative importance are still not clearly understood.