Dissecting aneurysms of posterior cerebral artery: clinical presentation, angiographic findings, treatment, and outcome

Parent Artery Occlusion for a Dissecting Posterior Cerebral Artery Aneurysm in the P4 Segment Presenting with Ischemic Stroke and Rapid Growth: A Case Report

A dissecting aneurysm in the P4 segment of the posterior cerebral artery (PCA) is extremely rare, and its treatment is sometimes challenging. Endovascular parent artery occlusion (PAO) was performed for an unruptured P4 segment dissecting PCA aneurysm presenting with ischemic stroke and rapid growth. A 70-year-old man was rushed to our emergency department due to a right-sided headache and a visual field defect. Head magnetic resonance imaging showed a right occipital lobe ischemic stroke, with right PCA occlusion and aneurysm formation in the P4 segment. The diagnosis was PCA dissection in the calcarine artery, and oral aspirin was started. Within a week, the dissecting aneurysm had enlarged progressively to 6.2 mm in diameter. Thus, PAO with coils was performed as a preventive measure against aneurysm rupture, assuming that complication risks were low because the tributary area of the dissecting PCA had already infarcted. A 6-Fr guiding sheath was introduced from the right brachial artery to the right vertebral artery, and a microcatheter/microguidewire was placed into the true lumen of the calcarine artery distal to the aneurysm. PAO with coils was performed, and the blood flow to the aneurysm was completely obliterated. After the treatment, the known infarction in the right occipital lobe was enlarged, but no new neurological symptoms developed. The patient was discharged independently on postoperative day 3. Treatment for a distal PCA dissecting aneurysm is challenging. PAO with coils is one of the reasonable choices, especially when a visual field defect has already developed.

Spectrum of Posterior Cerebral Artery Dissection: A Retrospective Observational Study and a Critical Review

Background and Aims

Intracranial arterial dissections commonly involve the vertebrobasilar system leading to subarachnoid hemorrhage (SAH) or cerebral infarction attributable to a dissecting aneurysm of the vessel or occlusion of the lumen depending on the depth of dissection. However, isolated posterior cerebral artery dissections (PCADs) are rare and sparsely reported in the literature.

Methodology

A retrospective multicentric observational study was carried out after collecting data from 14 patients admitted with PCAD in three hospitals of Kolkata, Jaipur, and Patna within the period of July 2021 to June 2022.

Results

The median age of the population was 48.5 years, and 64.28% were females. SAH was the most common presentation with dissecting aneurysms in all patients barring one, who presented with a left occipital infarct consequent to ipsilateral PCAD. Among the 14 patients, three patients denied endovascular intervention and were lost to follow-up; one patient with an occipital infarct and another patient with a dissecting left P3 aneurysm, which underwent spontaneous thrombosis, were managed conservatively. Among the nine patients scheduled for endovascular coiling, one patient succumbed before intervention and one patient succumbed to sepsis in the postoperative period. A complete recovery was noted in six patients, whereas residual neurodeficits were present in three patients. Among the six patients who had an uneventful recovery at the end of 3 months, five patients had an endovascular intervention.

Conclusion

PCAD may present with large-scale neurodeficits and is associated with high morbidity and mortality, hence necessitating prompt management. Conservative management is preferable for consequent infarcts, whereas endovascular management is desirable in cases of dissecting aneurysms, which usually tend to have a favorable outcome if intervened early.

Natural history and management of posterior cerebral artery aneurysms: a systematic review and meta-analysis of individual patient data

We conducted a comprehensive review and meta-analysis to investigate clinical, radiographic characteristics, and treatment outcomes of posterior cerebral artery aneurysms (PCAA). We systematically reviewed English-language articles investigating available treatments (parent artery occlusion (PAO), microsurgery, reconstructive endovascular (rEVT), and conservative treatments) for PCAA and analyzed the based on aneurysm morphology and rupture status. Six-hundred-eighty-five patients with 698 PCAA were identified from 59 studies. Overall, 371 (54.2%) aneurysms were ruptured, 325 (49%) were saccular, and 342 (51%) were non-saccular aneurysms. The mean age of the saccular was lower (40 years) than non-saccular aneurysm group (50 years) (P < .05). In ruptured PCAA, favorable clinical outcomes were comparable between the treatment groups except for patients treated conservatively, which had lower rates of favorable clinical outcomes (35.6%) and higher mortality (55.7%) (P < .0001). Ruptured aneurysms treated with rEVT (22.6%) had the highest recanalization rates compared to PAO (9.2%, P = 0.0001) and microsurgery (3.8%, P = 0.005). In unruptured PCAA, clinical outcomes were similar; higher complication rates were noted in microsurgery (40.4%, P = 0.026) and PAO (21.5%, P = 0.015) compared to rEVT (13.2%), which had higher recanalization rates (15.6%, P < .0001). The rates of subsequent stroke following PAO were 21.8% for unruptured and 32.3% for ruptured PCAA (P = 0.078). Ruptured PCAA portend worse prognosis and typically require an intervention to achieve better outcome whereas the benefit of an intervention in unruptured PCAA is much less clear. rEVT is promising for PCAA management with a good clinical and safety profile but more recurrence compared to PAO and microsurgery.

Bypass surgery for ruptured dissecting aneurysms of the proximal posterior cerebral artery: illustrative case

BACKGROUND

Posterior cerebral artery (PCA) dissecting aneurysms commonly occur in the proximal PCA and are considered rare. The treatment of proximal PCA dissecting aneurysms is challenging because of the existence of perforators supplying the vital neural structures. Recently, endovascular intervention has been used; however, concerns for ischemic or hemorrhagic complications exist.

OBSERVATIONS

A 54-year-old woman presented with subarachnoid hemorrhage due to dissecting aneurysm rupture at the P1-P2 junction of the PCA. The thalamoperforating artery (TPA) and medial posterior choroidal artery (MPchA) originated from the proximal end and the distal end of the aneurysm, respectively. Additionally, the posterior communicating artery (PcomA) connected with the dissected segment. To preserve these perforators, we performed surgical trapping combined with superficial temporal artery (STA) PCA anastomosis. Clips were applied for trapping the proximal and distal end of the aneurysm, with preservation of the TPA and MPchA origin. PcomA was left open for blood flow preservation to the perforators directly arising from the aneurysm. The postoperative course was uneventful, and the patient was discharged.

LESSONS

Surgical trapping using STA-PCA bypass could be a treatment of choice for proximal PCA dissecting aneurysms, considering its potential for cure and prevention of ischemic complications.

Posterior cerebral artery dissection after excessive caffeine consumption in a teenager

Arterial ischemic stroke is a rare but significant cause of neurological deficits in childhood. Even though there is a variety of risk factors, identifying the etiology can sometimes be a hard diagnostic challenge. Arteriopathies in general, and more specifically, arterial dissection is one of the uncommon pathologies that can cause incidents of pediatric stroke. We report a rare case of a young adolescent with posterior cerebral artery dissection after excessive consumption of caffeine, contained in energy drinks, only hours before the onset of neurological symptoms. A complete neuroimaging evaluation (MRI, intracranial US and digital subtraction angiography) at the admission and during the follow-ups supported the diagnosis of arterial dissection possibly caused by caffeine overconsumption.

Superficial Temporal Artery (STA)-Posterior Cerebral Artery (PCA) Bypass through Zygomatic Anterior Temporal Approach for Complex PCA Aneurysm: Technique Notes

BACKGROUND

Posterior cerebral artery (PCA) aneurysms are rare and the majority are giant, dissecting, or fusiform in morphology. Proximal occlusion of PCA without revascularization causes a high risk of ischemic complications. This study aimed to evaluate the safety and validity of using superficial temporal artery (STA)-posterior cerebral artery (PCA) Bypass through zygomatic anterior temporal approach in complex PCA aneurysms.

METHODS

Trapping or resecting of the aneurysms and reconstruction of the distal PCA through a zygomatic anterior temporal approach were performed in 6 patients from June 2017 to August 2020. Postoperative angiography was used to confirm the obliteration of the aneurysms and the patency of bypass artery. Neurologic function was assessed by the modified Rankin Scale.

RESULTS

Four male and 2 female patients with a mean age of 43.8 years (Range, 21-58 years) were assessed. Subarachnoid hemorrhage occurred in 5 patients, including 3 patients with Hunt-Hess grade IV, 2 patients with grade III, and 1 patient with grade I. All PCA aneurysms were treated with trapping or resecting of the aneurysms and revascularization of the distal PCA. Postoperatively, all aneurysms were eliminated and no new permanent neurological deficit was found. During the follow-up, Modified mRS of all patients were improved: There were 2 patients with mRS Score 0, 1 patient with mRS Score 1, 1 patient with mRS Score 3, and 2 patients with mRS Score 4. The long-term graft patency rate was 100%.

CONCLUSION

The STA-PCA bypass appears to be a safe and effective method for the treatment of complex PCA aneurysms requiring supplementing the blood flow in the area of the PCA. We established a surgical route, allowing the procedure to be done through the zygomatic anterior temporal approach. This approach provides adequate operative field exposure and reduces retraction of the temporal lobe.

Radical treatment of ruptured dissecting aneurysm on the P1 segment with monotherapy using multiple LVIS stents

The standard endovascular treatment for ruptured dissecting aneurysm is a parent artery occlusion. However, this treatment is unsuitable when the artery of the lesion gives off perforating vessels that supply blood to critical regions or when the collateral flow cannot be expected due to the sacrifice of the parent artery. Here, we present an infrequent case of ruptured dissecting aneurysm on P1 segment of the posterior cerebral artery. The aneurysm had little sac for coiling and the artery of the lesion had some perforator branches; thus, we selected the monotherapy with three overlapping low-profile visualised intraluminal support stents as radical treatment, which resulted in prompt obliteration of the aneurysm. The patient was fully recovered at 3 months after the procedure. Previous studies have reported the effectiveness of multiple stents alone for dissecting aneurysms, whereas this case showed that overlapping stents may also be effective on the P1 segment.

Stent-Assisted Coil Embolization for Acute Ruptured Dissecting Aneurysm at the P2 Segment of the Posterior Cerebral Artery: A Case Report

Objective

We report a case of ruptured posterior cerebral artery (PCA) dissecting aneurysm treated with stent-assisted coil embolization in the acute phase of ruptured aneurysm.

Case Presentation

A 60-year-old woman presented with sudden onset of severe headache followed by unconsciousness. CT showed severe subarachnoid hemorrhage. Digital subtraction angiography showed a dissecting aneurysm at the P2 segment of the right PCA. Stent-assisted coil embolization was performed for the ruptured dissecting aneurysm. Since thrombus was observed in the stent, ozagrel was administered intravenously, and the thrombus gradually disappeared during the follow-up period. She was discharged without neurological deficit.

Conclusion

Parent artery occlusion is widely performed for acute ruptured PCA dissecting aneurysm, but reconstruction with stent-assisted coiling is considered to be an effective therapeutic strategy.

Endovascular management of dissecting posterior cerebral artery aneurysm associated with persistent hypoglossal artery: A case report

Persistent embryological connections between the anterior and posterior circulations are rare entities. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis. As it is often associated with hypoplasia of vertebral arteries, it poses a challenge during endovascular interventions. We present a case of a 32-year-old woman who presented with occipital headache of four weeks’ duration. Magnetic Resonance Angiography showed hypoplastic vertebral arteries with a persistent hypoglossal artery arising from the cervical segment of the left internal carotid artery and supplying the entire posterior circulation, associated with a dissecting aneurysm of the right posterior cerebral artery. Endovascular parent vessel occlusion was performed for the dissecting posterior cerebral artery aneurysm by navigating the guide catheter, microwire, and microcatheter through the persistent hypoglossal artery because the vertebral arteries were hypoplastic. Post-intervention, the patient did not develop any neurological deficit and was discharged in a stable condition.

Selection of approach and bypass for fetal-type posterior cerebral artery aneurysm: illustrative cases

BACKGROUND

Unlike in aneurysms of the adult-type posterior cerebral artery (PCA), in aneurysms of the fetal-type PCA, parent artery occlusion (PAO) results in vascular insufficiency and major ischemic strokes. Preservation or reconstruction of fetal-type PCAs is necessary to prevent these complications. Furthermore, it is necessary to select an appropriate bypass method and approach for revascularization of the PCA.

OBSERVATIONS

The authors report 2 cases of aneurysms of fetal-type PCAs that were successfully treated with PAO with revascularization. A 38-year-old man with a large unruptured right PCA aneurysm at the postcommunicating (P2) segment underwent trapping with superficial temporal artery–PCA bypass via the anterior temporal and subtemporal approaches. In addition, a 45-year-old woman with a left PCA aneurysm at the quadrigeminal (P3)–cortical (P4) segments resulting in subarachnoid hemorrhage underwent proximal clipping of the P3 segment via the occipital interhemispheric approach with an occipital artery–PCA bypass. Although she had perforator infarction, major ischemic stroke was prevented, and aneurysm occlusion was accomplished in both cases.

LESSONS

Aneurysms of fetal-type PCAs pose a risk of ischemia due to PAO. The combined use of bypass and revascularization should be considered to prevent major ischemic stroke after occlusion of the fetal-type PCA. However, perforator infarction is a concern.

Traumatic dissecting pathology of posterior cerebral artery: a report of two cases-aneurysm and pial arteriovenous fistula

We present two cases of 17-year-old man and 10-year-old boy presenting with subarachnoid haemorrhage and a history of road traffic accident. One patient had dissecting aneurysm of the posterior cerebral artery (PCA), and the other patient had partially thrombosed aneurysm on CT angiography. On digital subtraction angiography of the second patient, there was formation of PCA pontomesencephalic vein pial arteriovenous fistula (PAVF). Both the patients underwent endovascular treatment: stent-assisted coiling for aneurysm and coiling with parent vessel occlusion for PAVF. There were no procedural complications. Follow-up angiography showed no residual aneurysm or fistula. Trauma is one of the recognised causes of dissection, and intracranial dissections can present as stenotic lesions, aneurysms or fistulas, depending on the pathology. Traumatic dissecting PCA aneurysm has been reported in only two case reports previously, and post-traumatic PAVF in PCA has not been reported.

ENDOVASCULAR MANAGEMENT OF INTRACRANIAL ANEURYSMS ON DISTAL ARTERIAL BRANCHES: ILLUSTRATIVE CASE SERIES AND LITERATURE RETROSPECTION

Intracranial aneurysms located on distal arterial branches are sporadic and scarce. They account for 2%-7% of the middle cerebral artery and 0.7%-2.3% of the posterior cerebral artery aneurysms, where they mainly arise distally from the P2-related sites. Such aneurysms usually remain asymptomatic prior to rupture, making their diagnosis and management really demanding. Endovascular treatment comprising of different neurointerventional techniques is becoming the most operational up-to-date routine to approach distal cerebral branch aneurysms. In this single-institution case series, endovascular selective coiling and/or parent vessel occlusion resulted in successful and total aneurysmal exclusion from cerebral circulation, which brought good recovery. Hereby, we present an illustrative case series of distal arterial branch intracranial aneurysms, discussing their possible etiology and various endovascular management modalities. We also provide a literature retrospection concerned with this rare entity. In conclusion, due to their predisposition for rupture, distal branch intracranial aneurysms should be treated early and aggressively. We do believe that endovascular selective coil occlusion is the management method of choice, while parent vessel occlusion (with liquid embolics) is optimal when aneurysmal coiling cannot be achieved, or when distal cortical territory is well vascularized by strong collateral cerebral circulation.

Dissecting aneurysms of the posterior cerebral artery - A retrospective review of imaging, angiographic characteristics, endovascular management and outcome

PURPOSE

To review management, clinical and imaging outcomes of dissecting posterior cerebral artery (PCA) aneurysms with emphasis on endovascular management in the form of parent vessel occlusion (PVO) at a tertiary care center.

METHODS

Thirty-six dissecting PCA aneurysms (19 ruptured) encountered at our center between January 2013 and November 2019 were reviewed for aneurysm location/size/presence of fetal PCA/management. Postprocedural imaging of patients who underwent endovascular intervention was reviewed for PCA territory infarcts and clinical records assessed for presence of neuro-deficits and outcome. None of the patients underwent a balloon test occlusion (BTO) prior to PVO.

RESULTS

The location of the aneurysms was as follows-P1 = 8/P1-P2 = 11/P2 = 5/P2-P3 = 10/P3 = 2. The mean size was 11.7x6.8 mm. Endovascular intervention was carried out in 20 patients in the form of PVO with coiling in 16 patients, coiling alone in 3 patients, and reconstruction of the left PCA with flow diverter deployment in one patient. Postprocedural PCA territory infarct was seen in 5 cases of PVO out of which 4 had a good functional recovery. Overall, 15/16 patients (93.7%) who underwent PVO had mRS ≤ 2 on follow-up. The single case with flow diverter also developed an infarct and had adverse outcome on follow up.

CONCLUSION

Among the various management strategies for dissecting PCA aneurysms, PVO is feasible and relatively safe even in absence of BTO in scenarios like critically ill patients with ruptured aneurysms, difficult access and financial constraints. Thromboembolic complications and antiplatelet therapy is a concern in reconstructive strategies.

[Intracerebral hemorrhage in the late period of internal carotid artery dissection]

Cervical artery dissection is the common cause of ischemic stroke in young and middle-age patients. According to our previous studies, dissection is related to arterial wall dysplastic changes, which in their turn are due to mitochondrial cytopathy. The authors describe three male patients who at the age of 53, 25 and 35 years underwent internal artery (ICA) dissection with occlusion of its lumen and subsequent recanalization in one of them. In 3.5 months, 13.5 years and 3 years respectively, patients developed intracerebral hemorrhage (IСH), which was not related to arterial hypertension, cerebral arterial aneurysms and anticoagulants. IСH were located on the side of ICA occluded after dissection (2 patients) or bilaterally in the territory of patent ICA (1 patient). Multivoxel ¹H-MR spectroscopy performed in one patient on 40 and 48 days after ICH revealed a high lactate peak in the externally unchanged hemispheric white matter. It is assumed that mitochondrial cytopathy in patients with dissection may involve large as well as small intracerebral arteries (mitochondrial microangiopathy), which could be the cause of ICH.

Revascularization of the upper posterior circulation with the anterior temporal artery: an anatomical feasibility study

OBJECTIVE In various disease processes, including unclippable aneurysms, a bypass to the upper posterior circulation (UPC) including the superior cerebellar artery (SCA) and posterior cerebral artery (PCA) may be needed. Various revascularization options exist, but the role of intracranial (IC) donors has not been scrutinized. The objective of this study was to evaluate the anatomical feasibility of utilizing the anterior temporal artery (ATA) for revascularization of the UPC. METHODS ATA-SCA and ATA-PCA bypasses were performed on 14 cadaver specimens. After performing an orbitozygomatic craniotomy and opening the basal cisterns, the ATA was divided at the M₃-M₄ junction and mobilized to the crural cistern to complete an end-to-side bypass to the SCA and PCA. The length of the recipient artery between the anastomosis and origin was measured. RESULTS Seventeen ATAs were found. Successful anastomosis was performed in 14 (82%) of the ATAs. The anastomosis point on the PCA was 14.2 mm from its origin on the basilar artery. The SCA anastomosis point was 10.1 mm from its origin. Three ATAs did not reach the UPC region due to a common opercular origin with the middle temporal artery. The ATA-SCA bypass was also applied to the management of an incompletely coiled SCA aneurysm. CONCLUSIONS The ATA is a promising IC donor for UPC revascularization. The ATA is exposed en route to the proximal SCA and PCA through the pterional-orbitozygomatic approach. Also, the end-to-side anastomosis provides an efficient and straightforward bypass without the need to harvest a graft or perform multiple or difficult anastomoses.

Optional Endovascular Therapy of Dissecting Posterior Cerebral Artery Aneurysm

BACKGROUND

Posterior cerebral artery aneurysms are uncommon, with an occurrence rate of less than 1% of intracranial aneurysms. They have various shapes, including saccular and fusiform. Dissecting aneurysms may occur in distal posterior cerebral artery and they may affect the whole artery. Endovascular therapy is considered as a safe method of treatment and there are different techniques for endovascular therapy.

SUMMARY

Posterior cerebral artery aneurysms are uncommon. Endovascular therapy is considered as a safe method of treatment and there are different techniques for endovascular therapy. We present here three cases collected from Maison Blanche Hospital (Intervention Neuroradiology Department, CHU Reims, France) during 2011-2012; they were females, at a young age and the affected side was on the right. The first case was affected at the P2-P3 segment, the aneurysm was fusiform in shape and she presented with ischemic stroke, while the second and third cases were affected at the P2 segment, the aneurysms being saccular in shape; one of them presented with subarachnoid hemorrhage with a history of migraine and the other patient presented with ischemic stroke. All of them had no history of trauma, hypertension or other diseases. One patient was treated by coiling and sacrificing the parent artery, the second patient was treated with stent-assisted coils, and the third one was treated by coiling without sacrificing the parent artery.

Endovascular treatment of posterior cerebral artery aneurysms: a single center's experience of 55 cases

OBJECTIVE Aneurysms of the posterior cerebral artery (PCA) are uncommon. To date, a limited number of studies have examined the outcomes of endovascular treatment for PCA aneurysms. The authors' aim in this study is to report their experience with the endovascular treatment of PCA aneurysms. METHODS Between January 2007 and December 2014, 55 patients with 59 PCA aneurysms were treated using the endovascular approach at the authors' institution. Twenty-three patients had 25 saccular aneurysms, and 32 patients had 34 fusiform/dissecting aneurysms. The endovascular modalities included the following: 1) selective occlusion of the aneurysm (n = 22); 2) complete occlusion of the aneurysm and the parent artery (n = 20); 3) parent artery occlusion (n = 6); 4) partial coiling of the aneurysm and the parent artery (n = 5); and 5) occlusion of the dissecting aneurysm sac (n = 2). RESULTS The immediate angiographic results included 45 complete occlusions (82%), 2 nearly complete occlusions (4%), and 8 incomplete occlusions (14%). The mean follow-up period of 21.8 months in 46 patients showed 37 stable results, 6 further thromboses, and 3 recurrences. The final results included 41 complete occlusions (89%), 2 nearly complete occlusions (4%), and 3 incomplete occlusions (7%). Procedure-related complications included the following: 1) rebleeding (n = 1); 2) infarction (n = 4); and 3) perforation (n = 1). There was 1 (1.8%) procedure-related death due to rebleeding, and 2 (3.6%) non-procedure-related deaths due to severe subarachnoid hemorrhage. Clinical outcomes were excellent (Glasgow Outcome Scale 5) in 47 of 49 patients at the long-term follow-up. CONCLUSIONS PCA aneurysms may be effectively treated by different endovascular approaches with favorable clinical and radiological outcomes. However, patients who present with severe SAH still have an overall poor prognosis. Partial coiling of the aneurysm and the parent artery is an attractive alternative treatment for patients who may not tolerate parent artery occlusion. Further study with a larger case series is necessary for validation of the durability and efficacy of this treatment.

Endovascular Treatment of the Posterior Cerebral Artery Aneurysms: Single-Center Experience and a Systematic Review

BACKGROUND

Endovascular treatment of posterior cerebral artery aneurysms is challenging because of the particular features of posterior circulation vessels. We performed a systematic review of the literature, to assess safety and efficacy associated to their endovascular treatment.

METHODS

Through a literature search, we identified 20 studies that met our inclusion criteria. We also performed a retrospective analysis of patients treated at our institution during the last 10 years. Demographics, angiographic features, clinical presentation, and outcome were extracted from each study. Data were combined using a random effects model and heterogeneity was assessed by I(2).

RESULTS

We retrieved 7 patients from our institutional series and 246 from the literature. Overall, 253/259 patients/aneurysms were included in this study. A selective coiling was performed in 27% of cases, a stent-assisted coiling in 2%, and a parent artery occlusion in 62%. Immediate complete/near-complete occlusion was obtained in 96% of cases and maintained in 90% at follow-up. No differences were observed between ruptured and unruptured aneurysms. Ischemic complications were reported in 15% of cases, although the most frequent was a hemianopsia in 7%; a hemiparesis was reported in only 2% of cases. Mortality was overall 1%. Ischemic complications were more frequent among patients who underwent nonselective treatment (P < 0.01).

CONCLUSIONS

Endovascular treatment of posterior cerebral artery aneurysms is associated with increased degree of occlusion and low recurrence rate. However, a parent artery occlusion implies complications, even although most of them are minor events such as hemianopsia.

Fetal-type posterior cerebral artery: the pitfall of parent artery occlusion for ruptured P2 segment and distal aneurysms

OBJECT

P2 segment and distal aneurysms are rare lesions of the cerebrovascular system. The efficacy and safety of endovascular occlusion for these types of aneurysms remain controversial. The aim of this study was to reveal risk factors for endovascular parent artery occlusion of ruptured P2 segment and distal aneurysms.

METHODS

Between March 2010 and November 2012, 812 patients with a ruptured intracranial aneurysm were admitted to the authors' hospital. Among them, 11 patients presented with P2 segment and distal posterior cerebral artery (PCA) aneurysms. These patients were subjected to endovascular treatment. Periprocedural data and clinical and angiographic records were studied retrospectively.

RESULTS

Of the patients with a ruptured PCA aneurysm, 2 of them underwent selective aneurismal coiling, and the remaining patients were treated with simultaneous occlusion of the parent artery. Patients with an adult-type PCA (n = 6), treated with either selective coiling or simultaneous parent artery occlusion, had no serious neurological deficits on follow-up. Four patients with a fetal-type PCA that was also occluded intraoperatively exhibited newly developed permanent paralysis and hemianopsia. However, 1 patient with a fetal-type PCA aneurysm that was selectively coiled recovered without complications. No recanalization was observed in any of the treated aneurysms.

CONCLUSIONS

Endovascular occlusion of an aneurysm and its parent artery is a safe and effective method for managing adult-type P2 segment and distal aneurysms. However, the authors' clinical data suggest that this method is of high risk for patients with fetal-type PCA aneurysms.

Posterior Cerebral Artery Pseudoaneurysm, a Rare Complication of Pituitary Tumor Transsphenoidal Surgery: Case Report and Literature Review

Endoscopic endonasal transsphenoidal surgery for pituitary tumors has been the standard therapy for decades. This approach offers surgeons an effective, safe, and wide exposure to the pituitary gland, with a relatively low mortality rate and acceptable complication rates. However, severe complications, including cerebrospinal fistula, meningitis, neural component injury, and vascular injury, may occur. One of the most common and severe complications is carotid artery injury; however, only 2 posterior cerebral artery injuries with pseudoaneurysm formation have been reported previously. One of them received bypass surgery and recovered well, but the other received endovascular treatment and died of intracranial hypertension. Herein, we report a rare case of iatrogenic pseudoaneurysm formation with hemorrhage after transsphenoidal surgery, in which tumor traction-related adjacent vessel injury was most likely. Aneurysm clipping, vascular bypass, and embolization are considered reasonable choices depending on the patient's condition for iatrogenic aneurysm formation. In our case, no surgical or endovascular intervention was performed, and the aneurysm healed spontaneously 3 weeks later.

The safety and efficacy of stenting in the treatment of complex posterior cerebral artery aneurysms: a seven-case report and literature review

OBJECTIVE

To investigate the safety and efficacy of stenting with coil in the endovascular treatment of complex posterior cerebral artery (PCA) aneurysms.

METHODS

The data on PCA aneurysms treated with stents were retrospectively reviewed from a prospectively collected intervention database. The literature was reviewed concerning the use of stents for PCA aneurysms.

RESULTS

Seven cases with complex PCA aneurysms (male: female = 6:1; ruptured: unruptured = 4:3) were retrieved from our database. Three aneurysms were localized at the junction of P1 and P2 segments (P1-2), two at P1, and two at P2A. Four were wide-necked saccular aneurysms, while the other three were dissecting ones. A total of nine stents (one Neuroform and eight Enterprise stents) were successfully deployed. Two aneurysms were totally eliminated, three were with neck residues and two were partially occluded. No procedure-related complications occurred. All patients recovered well. Angiographic follow-ups (FU) showed that three aneurysms achieved total obliterations, one got improved, two remained stable, and one recurred. The recurred aneurysm caused no symptom and was treated with two stents. Clinical FU demonstrated no neurological deterioration or bleeding. In literature review, the procedure-related mortality is 5.3 % (2/38). The incidence of permanent neurologic deficit is 2.6 % (1/38). Three (3/23) aneurysms recurred, of which one caused rebleeding. Four (4/23) in-stent stenoses were all asymptomatic. No other hemorrhagic or ischemic event occurred in clinical FU.

CONCLUSION

Stent offers a therapeutic alternative for complex PCA aneurysms especially when PVO cannot be tolerated. Long-term therapeutic efficacy requires further observations in clinical series with larger case numbers.

Superior cerebellar artery–posterior cerebral artery bypass: in situ bypass for posterior cerebral artery revascularization

Iatrogenic pseudoaneurysms are rare but serious complications of transsphenoidal surgery, and an iatrogenic pseudoaneurysm of the posterior cerebral artery (PCA) has been reported just once in the literature. The authors encountered such a case with a new P1 segment PCA pseudoaneurysm after endoscopic transsphenoidal resection of a pituitary adenoma. The aneurysm proved ideal for a novel intracranial–intracranial bypass in which the superior cerebellar artery (SCA) was used as an in situ donor artery to revascularize the recipient P2 segment. The bypass allowed aneurysm trapping without causing ischemic stroke or neurological morbidity. This case represents the first reported surgical treatment of an iatrogenic PCA pseudoaneurysm. Endovascular occlusion with coils was an option, but dolichoectatic morphology requires sacrifice of the P1 segment, with associated risks to the thalamoperforators and circumflex perforators. The SCA-PCA bypass was ideal because of low-flow demands. Like other in situ bypasses, it requires no dissection of extracranial arteries, no second incision for harvesting interposition grafts, and has a high likelihood of long-term patency. The SCA-PCA bypass is also applicable to fusiform SCA aneurysms requiring revascularization with trapping. This case demonstrates a dangerous complication that results from the limited view of the posterolateral surgical field through the endoscope and the imprecision of endoscopic instruments.