Surgical treatment of a basilar perforator aneurysm not accessible to endovascular treatment

An unusual etiology of subarachnoid hemorrhage, basilar artery perforator aneurysms, in Macao: Three case reports and review of literature

BACKGROUND

Subarachnoid hemorrhage is a severe neurological condition that requires prompt and appropriate treatment to prevent complications. Aneurysms are the most common cause of spontaneous subarachnoid hemorrhage. Conversely, basilar artery perforator aneurysms (BAPAs) are a rare etiology. There is no consensus on the optimal management of ruptured BAPAs in the acute setting.

CASE SUMMARY

We present a case series of 3 patients with ruptured BAPAs who were treated at our institution. Two patients had a modified Fisher grade of I, and one had a grade of IV on initial presentation. The aneurysms were detected by computed tomography angiography in two cases and conventional angiography in one case. The 3 patients underwent endovascular treatment with Guglielmi detachable coils. Post-treatment, the patients had good clinical outcomes, and follow-up brain computed tomography scans showed reduced subarachnoid hemorrhage without any new hemorrhage. However, one patient experienced a cerebral infarction 2 months later and eventually succumbed to the condition. The other 2 patients showed progressive recovery, and no aneurysm recurrence was observed at the 2-year follow-up.

CONCLUSION

Endovascular treatment may be a preferable approach for managing ruptured BAPAs compared with surgical intervention or conservative management. Early detection and prompt treatment is important to achieve favorable patient outcomes.

Basilar artery perforator aneurysms: a comparison with non-perforator saccular aneurysms

BACKGROUND

Basilar artery perforator aneurysms (BAPAs) are rare. There is no systematic description of their presentation, imaging, natural history and outcomes and how these compare to conventional non-perforator aneurysms. Thus, the authors in this study aimed to compare BAPAs to non-perforator aneurysms.

METHODS

Cases were identified from a prospective neurovascular database, notes and imaging retrospectively reviewed and compared to a consecutive series of patients with non-perforator aneurysms. Blood volume on CT and vessel wall imaging (VWI) were compared to controls.

RESULTS

9/739 patients with aneurysmal subarachnoid haemorrhage (aSAH) harboured BAPAs. Compared to 103 with aSAH from posterior circulation aneurysms, they were more likely to be male (6/9, p = 0.008), but of equal severity (4/9 poor grade, p = 0.736) and need of CSF drainage (5/9, p = 0.154). Blood volume was similar to controls (30.2 ml vs 26.7 ml, p = 0.716). 6/9 BAPAs were initially missed on CTA. VWI showed thick (2.9 mm ± 2.7) bright enhancement (stalk ratio 1.05 ± 0.12), similar to controls with ruptured aneurysms (0.95 ± 0.23, p = 0.551), and greater than unruptured aneurysms (0.43 ± 0.11, p < 0.001). All were initially managed conservatively. Six thrombosed spontaneously. Three grew and had difficult access with few good endovascular options and were treated through a subtemporal craniotomy without complication. None rebled. At 3 months, all presenting in poor grade were mRS 3-4 and those in good grade mRS 1-2.

CONCLUSIONS

Despite their small size, BAPAs present with similar volume SAH, WFNS grade and hydrocephalus to other aneurysms. They are difficult to identify on CTA but enhance strikingly on VWI. The majority thrombosed. Initial conservative management reserving treatment for growth was associated with no rebleeds or complications.

The Vertebrobasilar Trunk and Its Anatomical Variants: A Microsurgical Anatomical Study

BACKGROUND

The trunk of the basilar artery has not been included in microanatomy studies. Anatomical variants of the perforant branches of the vertebrobasilar trunk and their relationship with neural structures are very important in surgical approaches. Surgical dissection for the treatment of vascular lesions requires a perfect knowledge of the microsurgical anatomy.

METHODS

We conducted a descriptive analysis of 50 brains, which were fixed with formalin at 10% for 2 weeks, and the arterial system was injected with colored latex. After microsurgical dissection, it was divided into three segments: the lower portion went from the anterior spinal artery to the anteroinferior cerebellar artery, the middle segment was raised from the upper limit of the lower portion to the origin of the superior cerebellar artery, and the upper segment ranged from the previous portion until the origin of the posterior cerebral artery.

RESULTS

The basilar artery had an average length of 30 mm. The average diameter at its junction with the vertebral arteries was 4.05 mm. The average middle segment was 3.4 mm in diameter and 15.2 mm in length. The diameter of the upper segment was 4.2 mm, and its average length was 3.6 mm. The average number of bulbar arteries was three, and their average diameter was 0. 66 mm. The number of caudal perforator arteries were five on average, with a diameter of 0.32 mm. We found three rare cases of anatomical variants in the vertebra-basilar junction.

CONCLUSIONS

The basilar artery emits penetrating branches in its lower, middle, and upper portions. The origin of penetrating branches was single or divided after forming a trunk. However, we observed long branches from perforant arteries.

Ruptured basilar artery perforator aneurysm mimicking superior cerebellar artery aneurysm

BACKGROUND AND IMPORTANCE

The diagnosis of basilar artery perforator aneurysm is difficult due to their small size, with high rates of negative angiography. Furthermore, due to the considerable variation of basilar artery perforator (BAP), even if an aneurysm originates from a BAP, it is often difficult to clearly identify its origin on angiography.

CLINICAL PRESENTATION

A 46-female patient presented with World Federation of Neurological Surgeons Scale 1 subarachnoid hemorrhage. Initial imaging study, including digital subtraction angiography (DSA), revealed no vascular lesions. Two-week after admission, DSA revealed an aneurysm arising from the left superior cerebellar artery (SCA). Endovascular coil embolization was planned first. However, aneurysm selection using microcatheter was failed. Then, surgical approach was done via pre-temporal approach. We identified SCA, but there was no aneurysm. Further dissection revealed an aneurysm arising from basilar artery perforator, which was overlapped by SCA. The parent artery of the aneurysm arose from juxtaproximal to the orifice of left SCA, and crossed SCA at the juxtadistal to the aneurismal sac. Complete clip occlusion was done preserving BAP. After the surgery, the patient developed diplopia without extraoccular movement limitations. Two-month after the surgery, she was fully recovered without any neurologic deficits.

CONCLUSION

It is crucial to adequately consider the possibility of open surgery as a viable option in case that endovascular treatment of aneurysms originated from the distal segment of basilar artery proves unsuccessful.

Ruptured Basilar Artery Perforator Aneurysm Definitely Diagnosed with Intraoperative Microsurgical Findings: Case Report and Literature Review

Initial three-dimensional computed tomography and cerebral angiography fail to identify any aneurysm in 20% of cases of subarachnoid hemorrhage. Basilar artery (BA) perforator aneurysms are rare, and approximately 30%-60% were not identified by initial angiography. A 71-year-old male was transferred with a sudden onset of headache and loss of consciousness. Computed tomography demonstrated subarachnoid hemorrhage, but no ruptured aneurysm was detected. Repeat preoperative cerebral angiography indicated a bifurcation aneurysm of the circumflex branch of the superior cerebellar artery perforator, but microsurgical observation identified the BA perforator aneurysm. If the location of the BA perforator aneurysm cannot be clearly identified, as in this case, repeat angiography should be considered, and the treatment strategy should be decided based on a detailed consideration of the site of the aneurysm.

Transpetrosal Approach to a Ruptured Distal Basilar Perforating Artery Aneurysm

Basilar perforating artery aneurysms are rare and underreported vascular anomalies in the cerebrovascular literature. Various open and endovascular treatment approaches can be employed to treat these aneurysms based on several patient- and aneurysm-specific factors. Some authors have even advocated for conservative, nonoperative management. Here, we report a case of a ruptured distal basilar perforating artery aneurysm secured by an open transpetrosal approach. A 67-year-old male presented to our institution with a Hunt-Hess grade 2, modified Fisher grade 3 subarachnoid hemorrhage (SAH). Initial cerebral digital subtraction angiography (DSA) did not identify an intracranial aneurysm or other vascular lesions. However, the patient had a re-rupture event several days after presentation. DSA at this time revealed a posteriorly projecting distal basilar perforating artery aneurysm. Initial attempts with endovascular coil embolization were unsuccessful. Thus, an open transpetrosal approach was taken to gain access to the middle and distal basilar trunk to secure the aneurysm. This case underscores the unpredictability of basilar perforating artery aneurysms and the challenges encountered when considering active treatment. We demonstrate an open surgical approach with an intraoperative video for definitive management after failed attempted endovascular treatment.

Spontaneous subarachnoid hemorrhage caused by ruptured aneurysm of basilar trunk perforator: a case report and literature review

Background

Aneurysm of basilar perforator was rarely reported in the literature. It is difficult to treat due to its small size and deep-seated location. Excessive treatment may cause complications that resulted from ischemic events of parent perforators. Therefore, it is important to make clinical strategy for such patients to improve the prognosis.

Case presentation

One case, who presented as spontaneous subarachnoid hemorrhage, despite the negative result in computed tomography angiography firstly, was diagnosed angiographically as a ruptured aneurysm of the basilar perforator. A good clinical outcome of the case was achieved during the follow-up after conservative observation for 2 months, as well as the disappearance of previous lesion from angiography.

Conclusions

Aneurysm located at perforator of basilar trunk was rare and difficult to treat. Conservative observation for certain cases with periodic angiography follow-up was considered in order to prevent the patients from potential iatrogenic effects.

Ruptured basilar artery perforator aneurysm: a novel mechanism of pure subarachnoid hemorrhage in moyamoya disease. Illustrative case

BACKGROUND

Pure subarachnoid hemorrhage (SAH) in patients with moyamoya disease is a rare occurrence. Three underlying mechanisms have been described previously, except for ruptured aneurysm of the circle of Willis. Herein, the authors describe a novel mechanism: rupture of a perforator aneurysm in moyamoya disease.

OBSERVATIONS

A 51-year-old man experienced sudden onset of severe headache and vomiting. Computed tomography showed diffuse SAH. Digital subtraction angiography (DSA) showed unilateral moyamoya disease without remarkable etiology of SAH. The patient underwent conservative management with antihypertensive agents. The second DSA on day 17 revealed a slow-filling aneurysm emerging from the basilar top perforating artery. The diagnosis of SAH due to unknown origin was changed to ruptured basilar artery perforator aneurysm (BAPA). The third follow-up DSA on day 159 revealed the resolution of BAPA.

LESSONS

In the case of pure SAH, it is crucial to consider the possibility of perforator aneurysms due to hemodynamic stress caused by moyamoya disease. Repeated DSA is essential for detecting the lesion.

Detection of Angiographically Occult Ruptured Basilar Sidewall Perforator Aneurysm by Vessel Wall MR Imaging

Basilar artery perforator aneurysms are rare with a prevalence of less than 1%. These are particularly challenging to detect given their small size and tendency to intermittently thrombose. We describe a case of a ruptured basilar artery sidewall perforator aneurysm that was angiographically occult on computed tomographic angiogram and cerebral catheter angiogram. One day after the initial diagnostic work-up, intracranial vessel wall MR imaging (VWI) was performed which revealed a small outpouching along the right posterolateral basilar arterial wall with a punctate enhancing focus suggestive of a thrombosed basilar perforator artery aneurysm. Thrombus within the small aneurysm sac likely contributed to the poor opacification of the aneurysm sac on conventional lumen-based imaging techniques. Ruptured aneurysms have high morbidity and mortality due to their tendency to rebleed, making their expedient detection and treatment imperative. This case highlights the role VWI can play in detecting small ruptured aneurysms that intermittently thrombose and are otherwise challenging to diagnose with conventional vessel imaging.

Comparison between stenting and conservative management of posterior circulation perforator aneurysms: Systematic review and case series

PURPOSE

Posterior circulation perforator aneurysms (PCPAs) are a rare type of intracranial aneurysms whose natural history and optimal clinical management are still largely unexplored. This study aims to report our experience with treating ruptured PCPAs and to provide a systematic review of the literature to compare the two most established treatment options, endovascular stenting, and conservative management including administration of antifibrinolytic drugs and watchful waiting.

METHODS

We performed a systematic review of the literature following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Major databases were searched for case reports and case report series written in the English language between 1995 and 2020. Additionally, we retrospectively reviewed our stroke center database for cases of ruptured PCPAs between January 2014 and July 2020. Endovascular stenting and conservative treatment were compared using endpoints, including favorable outcome rate (mRS 0-2), occlusion rate, mortality rate, periinterventional complication rate, and re-hemorrhage rate.

RESULTS

We identified 31 patients treated endovascularly using stents and 33 patients treated conservatively, with the administration of antifibrinolytic drugs in 3 of them. Our analysis showed no statistically significant difference between the groups, except for the occlusion rate.

CONCLUSIONS

The optimal management strategy of PCPAs is still unknown, but stenting can be considered as an effective occlusion method with an acceptable complication rate. Preventive ventricular drainage may be necessary due to the high hydrocephalus rate encountered in ruptured PCPAs.

Ruptured Basilar Artery Perforator Aneurysm: A Case Report and Review of the Literature

Basilar artery perforator aneurysms (BAPAs) are a rare cause of subarachnoid hemorrhage (SAH), and the natural history is still unknown. Herein, we report a case of ruptured BAPA that appeared during the observation period and then spontaneously disappeared; we have also conducted a review of the literature and performed an analysis based on the type of management. This case of BAPA had a unique course, and our observations may help establish a treatment strategy. A 60-year-old man presented with acute diffuse SAH, World Federation of Neurosurgical Societies (WFNS) Grade II and Fisher Grade 3. Initial three-dimensional digital subtraction angiography (DSA) did not show the source of the hemorrhage. DSA performed on day 39 showed a BAPA with a diameter of 3 mm at the posterior surface of the upper third of the basilar artery. Conservative treatment was chosen. DSA performed on day 64 showed complete resolution of the aneurysm. BAPAs are likely pseudoaneurysms, and not saccular aneurysms, caused due to dissection of basilar perforator arteries. BAPAs are often not recognized on initial imaging, and hence, it is necessary to repeat the DSA examination. Considering the relatively high rate of spontaneous resolution, we chose conservative management. When BAPAs enlarge or do not disappear after conservative treatment, additional therapy such as multiple stents should be considered.

A systematic review of non-trunk basilar perforator aneurysms: is it worth chasing the small fish?

BACKGROUND AND PURPOSE

Non-trunk basilar artery perforator aneurysms (BAPAs) are rare intracranial vascular pathologies that have long been underdiagnosed, under-reported, and under-analyzed. We performed a systematic review of the efficacy and safety endpoints between conservative and active treatment approaches for non-trunk BAPAs.

METHODS

Major databases were analyzed for relevant publications between 1995 and 2019. Studies comparing the outcomes between conservative and active treatment approaches such as coiling, stenting, clipping, liquid embolization, and flow diversion were included. Mortality rate, rate of permanent neurological deficit as determined by the modified Rankin Score (mRS), rate of second treatment occurrence, and perioperative complication rate were also assessed.

RESULTS

A total of 24 studies, including 54 patients with 56 non-trunk BAPAs, were included. The mean maximum aneurysm diameter was 2.70 mm (range 1-10). A diagnosis was achieved with the initial DSA in 50.0% (27/54) of the patients. A conservative approach was used in 16 patients while active treatment was used in the other 38. Thirteen of 15 (86.7%) patients in the conservative group and 27/34 (79.4%) in the active treatment group had an mRS score 0-2. A non-significant higher odds of a positive outcome was observed in the conservative group (OR 1.51, 95% CI 0.50 to 4.54). The event-related mortality rate was 3.55% (3/54) with one procedure-related death in the active treatment group.

CONCLUSIONS

In patients with non-trunk BAPAs unamenable to active treatment, conservative approaches may result in acceptable functional outcomes and low morbidity. Small sample sizes and under-reporting of outcomes warrant further study.

Should we treat aneurysms in perforator arteries from the basilar trunk? Review of 49 cases published in the literature and presentation of three personal cases

Basilar trunk perforator artery aneurysms are rare. Their diagnosis and treatment are difficult, controversial, and challenging. Analysis of 52 cases (49 documented in the literature and three personal cases) clearly shows a re-bleeding rate of 15% in patients whose aneurysm has not been occluded and 0% in treated patients ( p < 0.05). The most effective treatment, and the one that presents the least complication, is double-stenting across the basilar trunk.

Posterior circulation perforator aneurysms: a proposed management algorithm

INTRODUCTION

Subarachnoid hemorrhage (SAH) from posterior circulation perforator aneurysms (PCPAs) is rare and its natural history is unknown. Diagnosis may be difficult, acute management is poorly defined, and long-term recurrent SAH rates and clinical outcome data are lacking.

METHODS

We searched our institution's records for cases of PCPA rupture and analyzed patient demographics, Hunt and Hess (HH) grades, diagnostic imaging, management, and clinical outcomes. We conducted telephone interviews to calculate modified Rankin Scale (mRS) scores.

RESULTS

We identified 9 patients (6 male, 3 female) with a ruptured PCPA who presented to the University of Virginia Health System (Charlottesville, VA, USA) between 2010 and 2016. Median and mean ages were 62 and 63 years, respectively. Median HH grade was 3. Seven of nine (78%) PCPAs were angiographically occult on initial imaging and median time to diagnosis was 5 days. Three conservatively managed patients had a mean mRS score of 0.67 (range 0-1) at mean follow-up of 35.3 months. Antifibrinolytic therapy was administered to all conservatively managed patients without thrombotic complication. Six patients receiving endovascular treatment had a mean mRS score of 2.67 (range 0-6) at mean follow-up of 49.2 months. No cases of recurrent SAH were seen in the study.

CONCLUSIONS

The rarity of PCPA has precluded long-term clinical follow-up until now. Our experience suggests low recurrent SAH rates. Until further studies are performed, conservative management, possibly combined with antifibrinolytic therapy, may be a viable treatment with acceptable long-term outcome.

Basilar Perforator Aneurysms: Presentation of 4 Cases and Review of the Literature

OBJECTIVE

Basilar perforator aneurysms (BPAs) are rare lesions that present a therapeutic challenge. We present 4 cases of ruptured BPAs treated either conservatively or by flow diverter deployment and review the literature.

METHODS

Patients (age 78, 59, 53, and 62 years) presented with World Federation of Neurological Societies grade I-IV and Fisher grade 3-4 subarachnoid hemorrhage. Initial angiography results were normal in 3 patients and necessitated a second angiography. BPA diameter was 0.5-3 mm; BPAs were located in the mid-third of the basilar artery in 2 patients and the upper third in 2 patients.

RESULTS

All patients were managed conservatively. One patient experienced rebleeding 10 days after initial ictus, which required the deployment of a flow diverter in the basilar artery. One patient developed a severe spontaneous pontine ischemic stroke with severe quadriparesis and refused further imaging. He was clinically stable at 1-year clinical follow-up. The other 3 patients showed complete resolution of BPAs on control follow-up imaging.

CONCLUSIONS

Ruptured BPAs are rare lesions that may heal spontaneously or be associated with spontaneous ischemic brainstem stroke or rerupture. These lesions can be managed conservatively initially with flow diverter deployment the most suitable therapeutic alternative in selected cases. Larger studies are needed to fully understand the natural history and refine the therapeutic strategy for these lesions.

Large basilar perforator pseudoaneurysm: A case report

Basilar perforator aneurysms are rare and a communication between a basilar perforator and a separate pseudoaneurysm cavity is extremely rare. We describe a case presenting with high grade subarachnoid hemorrhage which on further investigation delineated a 2-3 mm dissecting basilar perforator aneurysm communicating superiorly into a contained 6 mm pseudoaneurysm cavity. This case illustrates an unusual neurovascular pathology with low potential for successful endovascular treatment such as coil embolization or intracranial flow diverter stenting. Conservative medical management remains the main stay of treatment for such poor surgical candidates.

Basilar artery perforator aneurysms (BAPAs): review of the literature and classification

Basilar artery perforator aneurysms (BAPAs) are an uncommon subtype of perforating artery aneurysms, with only 18 published cases since their initial description in 1996 by Ghogawala et al To date, there are only seven published cases of ruptured BAPAs treated using endovascular techniques. Given the rarity of these aneurysms, the natural history and ideal approach to treatment has not been established. We describe a new endovascular approach to treating these aneurysms using staged telescoping stents, summarize all published cases of BAPAs, and present a unique classification system to enable future papers to standardize descriptions.

Ruptured basilar artery perforator aneurysms--treatment regimen and long-term follow-up in eight cases

INTRODUCTION

Basilar artery (BA) perforator aneurysms may lead to severe subarachnoid hemorrhage (SAH). The acute management is uncertain. The anatomic approach is challenging both for coiling and clipping, and flow diverter stenting may be dangerous due to the required antiplatelet therapy. We report on our experiences in eight patients.

METHODS

We retrospectively analyzed eight patients with ruptured BA perforator aneurysm, including clinical characteristics, imaging data, treatment regimen, clinical course, and long-term outcome.

RESULTS

Patients presented with major SAH and World Federation of Neurosurgical Societies (WFNS) scores of I in three, II in two, and V in three cases. In four patients, the aneurysm was detected in the initial angiography, in four only in follow-up angiography. Five patients were treated conservatively and three patients had endovascular therapy. In the conservative group, the aneurysm spontaneously thrombosed in three cases. One patient suffered from a re-SAH and stayed permanently dependent due to an associated perforator stroke (modified Rankin Scale (mRS) 5). The remaining four patients recovered well (mRS 0 and 1 in two cases, each) including three patients also exhibiting perforator strokes. Regarding the endovascular group, one parent vessel was an angioma feeder and embolized with Onyx. The second aneurysm spontaneously thrombosed periinterventionally. The third patient underwent coiling. Two parent vessels were occluded postinterventionally, resulting in perforator strokes. Final mRS scores were 0, 2, and 2, respectively.

CONCLUSION

Conservative management of ruptured BA aneurysms might be a first-line treatment option with common spontaneous aneurysm occlusion, low rate of re-SAH, and promising clinical outcome.

Flow diverter stent treatment for ruptured basilar trunk perforator aneurysms

OBJECTIVE

Basilar trunk perforator (BTP) aneurysms are rare. Treatment options traditionally considered for these uncommon lesions have included direct surgery, endovascular therapy, or conservative management. Flow diverters represent a newer therapeutic option for BTP aneurysms but pitfalls and complications are unknown. We describe three patients with BTP aneurysms treated with flow diverter stents.

METHODS

All three patients had ruptured BTP aneurysms and, after loading doses of dual antiplatelet agents, underwent treatment with a flow diverter alone (two patients) or in combination with an intracranial stent (one patient).

RESULTS

Complications directly (two thromboembolic events) or indirectly (one hemorrhage at the external ventricular drain site, probably facilitated by the dual antiplatelet therapy) occurred in all three patients and resulted in permanent morbidity in one case. Imaging follow-up confirmed obliteration in all three patients, and no episodes of rebleeding from the aneurysms were observed at follow-up.

CONCLUSIONS

Flow diverters are effective in obliterating BTP aneurysms. However, given the challenges and complications encountered, especially in patients with ruptured lesions, their use must be carefully weighed against other available therapeutic modalities, including observation.

Spontaneous resolution of perforator aneurysms of the posterior circulation

The authors present the cases of 3 patients with ruptured perforator aneurysms of the posterior circulation. Patients were 39, 55, and 59 years old. None of the patients had relevant past medical or family history. All presented with World Federation of Neurosurgical Societies Grade I and Fisher Grade 2 or 3 subarachnoid hemorrhage. Initial angiography results were normal. A second cerebral angiogram in each case revealed a small (< 3 mm) aneurysm of perforator arteries of the posterior circulation. Patients were successfully managed conservatively. None of the patients developed symptomatic vasospasm, rebleeding, or hydrocephaly. Control angiograms at 3 months showed spontaneous resolution of the aneurysm in all cases. Rupture of perforator aneurysms of the posterior circulation is a rare condition and it may be underdiagnosed because of limitations of imaging techniques. Treatments can lead to complications in highly functional territories and should be considered wisely, especially due to the fact that the causes and natural history of such aneurysms are unknown and spontaneous healing remains a possibility.

Basilar trunk perforator artery aneurysms. Case report and literature review

Perforator artery aneurysms of the basilar trunk are rarely described in the literature. In addition to presenting our own case, we performed a PubMed search to comprehensively illustrate demographics, hemorrhage patterns, and treatment outcomes for these lesions. We found 12 patients with basilar perforator artery aneurysms. Mean patient age was 47.3, and there was a 3:1 male to female predominance. All patients had ruptured aneurysms, though all were clinically low or medium grade (I-III). Six patients had diffuse subarachnoid hemorrhage (SAH), and six had prepontine and/or perimesencephalic hemorrhage patterns. All aneurysms arose off middle or rostral basilar perforator arteries; mean aneurysm size was 4.5 mm. All except one was partially thrombosed, and 4 out of 12 patients did not have their aneurysms detected on initial angiography (33%). Seven were treated surgically, two were coiled, and three were observed. At last follow-up, all were occluded, and 8 out of 12 patients were neurologically intact (67%). Of seven patients that were not treated with early intervention, one suffered a rebleed over a combined total of 37.3 months of observation. Two aneurysms amenable to coiling were occluded without complication. Three of seven patients treated surgically had transient complications, though five were neurologically intact at follow-up. Basilar perforator artery aneurysms may be sources of hemorrhage in diffuse or perimesencephalic/prepontine SAH. While endovascular coiling is an excellent option if parent vessel anatomy allows for catheterization, many are unamenable to endovascular treatment. Surgical obliteration via proximal occlusion or trapping is a safe and effective means of treating these aneurysms.

An unusual aneurysm of a basilar perforating artery presenting with a subarachnoid haemorrhage

A 65-year-old man had a perimesencephalic subarachnoid haemorrhage with normal angiography initially. After a rebleed 5 days later, a repeat angiogram revealed a pea-like aneurysm a short distance behind and below the basilar bifurcation. It was not amenable to endovascular treatment and the feeding vessel was coagulated and divided at open surgery via a sub temporal approach. He developed a right hemiparesis and dysphasia, from which he slowly recovered. Basilar perforating artery aneurysms are extremely rare, with only 4 previous cases reported.

Petrosal approaches to posterior circulation aneurysms

Complex posterior circulation aneurysms are formidable lesions with an abysmal natural history. Their management continues to present a challenge to both endovascular and open microsurgical approaches. Affording an expansive, combined supra- and infratentorial exposure, the petrosal approaches are well suited for these challenging lesions when located along the basilar trunk or at a low-lying basilar apex. This report evaluates the evolution and application of petrosal approaches to these lesions. Excluding transsigmoid, infratentorial, or labyrinth-sacrificing approaches, the authors found 23 reports with 61 posterior circulation aneurysms treated via a petrosal approach. Although early morbidity was not negligible, rates of aneurysm occlusion (95% overall) and long-term outcome were quite laudable in light of the challenge posed by these lesions. Moreover, with accumulating experience with petrosal approaches, rates of complications are likely to wane, as neurosurgeons capitalize on the expansive exposure afforded by these indispensable approaches.

Report of two cases of a rare cause of subarachnoid hemorrhage including unusual presentation and an emerging and effective treatment option

PURPOSE

To report two cases of a rare cause of subarachnoid hemorrhage (SAH), including unusual presentation and an emerging and effective treatment option.

CASE REPORTS

Ruptured basilar perforator artery aneurysm is a rare cause of SAH. Catheter angiography in the immediate post hemorrhage period may be unrevealing. We report two cases of ruptured basilar pontine perforator aneurysms. In one of these cases the perforator aneurysm was not apparent on the initial or the 1 week follow-up angiograms. Both patients returned for follow-up angiography 2 months later by which time aneurysmal filling and conspicuity had increased. Both patients were treated solely with two overlapping Neuroform stents. Follow-up angiograms demonstrated complete resolution of the aneurysms in both patients.

CONCLUSIONS

Rupture of aneurysms arising from basilar artery perforators is a rare cause of SAH and attention to this area should be part of an interventionist's search pattern. Aneurysms in this area may not be apparent in the immediate post rupture setting and delayed post hemorrhage angiography has a role in detecting this entity. Stent monotherapy may be effective in treating these lesions.

An endovascular approach to ruptured aneurysms of the circumferential branch of the basilar artery

Aneurysms of the basilar perforating arteries are uncommon and those of the circumferential artery are particularly rare. Microsurgical clipping or trapping is the preferred treatment as these aneurysms are usually not accessible for endovascular treatment. We report two patients with ruptured aneurysms arising from the basilar circumferential artery. The first patient, a 66-year-old male, presented with a prepontine hematoma and a delayed filling aneurysm of the basilar circumferential artery. The second patient, a 28-year-old female, presented with a narrow-neck aneurysm of the basilar circumferential artery, associated with an arteriovenous malformation in the left cerebellum. Both patients were treated successfully with endovascular coiling, flow was preserved in the perforating parent vessels and the patients had excellent outcomes. This is the first report of this type of aneurysm being successfully treated by endovascular coiling. The treatment challenges regarding microsurgical and endovascular approaches are discussed.

Isolated posterior spinal artery aneurysm causing intracranial acute subarachnoidal hemorrhage

A case of an isolated posterior spinal artery aneurysm of the upper cervical spinal cord is presented. Spinal artery aneurysms that are not associated with other entities are extremely rare. Four cases have been reported in the literature to date. The patient developed symptoms and signs of intracranial subarachnoid hemorrhage. The aneurysm was successfully clipped. No other vascular abnormalities were seen.

Ruptured aneurysm at the perforating artery supplying the insula: case report

OBJECTIVE

Aneurysms originating from perforating branches of the middle cerebral artery are quite rare. Most of them arise from the lenticulostriate arteries, frequently located within the basal ganglia. We report a perforating artery aneurysm that was entirely embedded within the limen insulae.

CLINICAL PRESENTATION

A 41-year-old man presented with an insular hematoma without subarachnoid hemorrhage caused by rupture of a small aneurysm on a perforating artery of the proximal middle cerebral artery supplying the insula.

INTERVENTION

This rare aneurysm was resected via the transsylvian-insular approach.

CONCLUSION

Although very rare, perforating artery aneurysms should be considered in young or middle-aged patients with an atypical intracerebral hematoma. This report discusses radiological and surgical characteristics of this unusual aneurysm.

Subarachnoid haemorrhage due to a lateral spinal artery aneurysm misdiagnosed as a posterior inferior cerebellar artery aneurysm: case report and literature review

CLINICAL DESCRIPTION

A 61 year old man presenting with subarachnoid haemorrhage had a distal posterior inferior cerebellar artery (PICA) aneurysm diagnosed on the initial cerebral angiogram. However, a PICA aneurysm was not found during surgery. A follow-up, super-selective vertebral artery (VA) performed demonstrated a saccular aneurysm located on the lateral spinal artery (LSA). A right sub-occipital craniotomy was performed and the aneurysm arising was identified and obliterated with a small titanium clip.

CONCLUSION

We describe the first example of an LSA aneurysm without occlusion or severe stenosis of the VA and PICA. This extremely rare lesion illustrates how knowledge of the angiographic features and super-selective cerebral angiography aids the precise diagnosis and the prevention of surgical complications.

Combined endoscope-assisted transclival clipping and endovascular stenting of a basilar trunk aneurysm: case report

OBJECTIVE

We describe a patient with a mid-basilar aneurysm treated with combined endoscope-assisted transsphenoidal clipping and endovascular stenting.

CLINICAL PRESENTATION

A 28-year-old woman was transferred to the cranial base surgery center with an acute Grade III subarachnoid hemorrhage. Cerebral angiography demonstrated a small basilar trunk aneurysm that was not amenable to acute endovascular treatment.

INTERVENTION

The patient underwent sublabial transsphenoidal/transclival endoscope-assisted clipping of the aneurysm and subsequent stenting of the affected segment. The aneurysm was repaired with a low-profile Weck clip (Weck Closure Systems Research, Triangle Park, NC) that permitted a watertight closure of the clival dura using cardiac Medtronic U-clips (Medtronic, Inc., Minneapolis, MN). Postoperatively, the patient had no evidence of cerebrospinal fluid leakage.

CONCLUSION

Watertight dural closure was possible due to the use of a low-profile aneurysm clip that did not protrude through the dural defect, as well as self-tying sutures.

Distal aneurysms of basilar perforating and circumferential arteries. Report of three cases

Distal aneurysms of basilar perforating and circumferential arteries are exceedingly rare. The authors encountered one patient with a distal basilar perforating artery aneurysm and two with aneurysms arising from circumferential branches of the basilar artery (BA). The diagnostic features, microsurgical treatment, and outcomes in these three patients are described. The first patient, a 27-year-old man, presented with an angiogram-negative subarachnoid hemorrhage (SAH), and subsequent readmission for a new hemorrhage revealed a centrally thrombosed aneurysm arising from a basilar apex perforating artery. The second patient, a 68-year-old man, presented for follow-up evaluation 2 months after an angiogram-negative SAH, and an aneurysm was identified on a circumferential artery originating from the BA trunk. The third patient, a 2-year-old boy, presented with blunt head trauma and a pseudoaneurysm arising from a basilar apex circumferential artery. All three aneurysms were managed microsurgically with aneurysm trapping, via either an orbitozygomatic or an extended retrosigmoid approach. Occlusion of the distal perforating or circumferential artery was well tolerated in all cases, with no neurological sequelae resulting from surgery. Features common to all three aneurysms were dolichoectatic morphology, intraluminal thrombus, and SAH. These aneurysms may be difficult to diagnose given their small size and delayed filling on angiographic studies. Consequently, their presence in cases of angiogram-negative SAH may be underestimated. These aneurysms are not amenable to endovascular treatment, but excellent results can be obtained with microsurgical exposure and trapping.