Intracranial vertebral artery dissections: clinical, radiological features, and surgical considerations

An Unusual Case of Ehlers-Danlos Syndrome Presenting as Proptosis

Ehlers-Danlos syndrome (EDS) is a rare, heterogeneous group of genetic connective tissue disorders that affect collagen proteins. Currently, they are classified into 13 subtypes, many of which share general characteristics such as thin, hyperextensible skin and joint hypermobility. Vascular Ehlers-Danlos syndrome (vEDS) is characterized by tissue fragility, which predisposes individuals to premature arterial, uterine, or intestinal rupture. In this case, a young female presented with proptosis, skin hyperelasticity, and multiple joint dislocations. On computed tomography angiography (CTA), a direct caroticocavernous fistula, along with multiple segments of narrowing and ectasia in the internal carotid arteries and vertebral arteries, were detected, leading to a diagnosis of vEDS. This case report highlights the importance of clinical evaluation and the role of imaging in detecting this rare condition.

Microsurgical Treatment Strategy of Vertebral Artery Fusiform Aneurysm-From the Standpoint of Hemodynamic Integrity and Perforator Preservation

During treatment of vertebral artery (VA) fusiform aneurysms, it is critical to preserve peripheral perforators and anterograde blood flow of the VA and to reduce hemodynamic load to the contralateral VA. Even in the era of endovascular treatment, there are still many benefits to using microsurgical treatments with appropriate clip application and preservation of the perforators around the aneurysm, in conjunction with various bypass techniques. The ideal microsurgical technique involves reconstructive clipping that obliterates the aneurysm but preserves anterograde blood flow of the VA, followed by isolation of the aneurysm and VA reconstruction. If these two methods are unavailable, proximal clipping of the aneurysm combined with flow-augmentation bypass to the distal branch can be considered as an alternative surgical management. We discuss the microsurgical treatment of unruptured VA fusiform aneurysms in our surgical cases on the basis of a review of the current literature.

Endovascular treatment for ruptured vertebral dissecting aneurysms involving PICA: Reconstruction or deconstruction? Experience from 16 patients

OBJECTIVE

Ruptured vertebral dissecting aneurysms (VDAs) with posterior inferior cerebellar artery (PICA) involved require an optimal method to isolate the dissection and prevent the symptomatic infraction. This study aims to present our experience with both parent artery occlusion (PAO) and stent-assisted coiling (SAC), and provide a favorable strategy to the management of ruptured VDAs with PICA involved.

METHODS

We retrospectively reviewed patients with subarachnoid hemorrhage in our database from March 2013 to December 2018, suffering from dissecting aneurysms of the intradural vertebral arteries and endovascularly treated. A total of 16 cases with PICA involved were included. Basic information, aneurysm characteristics, procedure related complications and outcomes of patients were analyzed.

RESULTS

10 (62.5%) aneurysms were managed with PAO containing 3 proximal occlusion and 8 targeted-trapping preserved the PICA. 5 (31.3%) aneurysms were treated with SAC and one 6.3%) treated with vertebral artery to PICA stenting and trapping. Two (12.5%) patients died in the acute phase. Good clinical outcomes (modified Rankin Scale 0 to 3) were observed in 13(81.5%) cases in 30 days follow-up. PICA territory infraction was happened in one patient without any dysfunction. Favorable occlusion was observed in 9 of 12 (75%) which were free of further treatment.

CONCLUSIONS

For patients with good contralateral circulation, PAO could be a first line management for ruptured VDAs with PICA involved. Targeted-trapping with either reserved PICA or proximal occlusion with moderate coiling in aneurysm are promising modalities to prevent severe PICA infraction.

Treatment of intracranial vertebral artery dissecting aneurysms involving the posterior inferior cerebellar artery origin

Background

Vertebral artery dissecting aneurysm (VADA) involving the origin of the posterior inferior cerebellar artery (PICA) is a complex disease entity in which the dual goals of preventing future rebleeding and maintaining perfusion of the lateral medulla must be considered. We present an illustrative case and review the literature surrounding treatment strategies.

Case Description

We report a patient presenting with extensive subarachnoid hemorrhage due to rupture of an intracranial VADA involving the PICA origin. After consideration of the patient's cerebral vasculature and robustness of collaterals, a flow-diverting stent was placed with angiographic resolution of the lesion and maintenance of antegrade PICA flow. Ultimately, the patient experienced a contralateral intraparenchymal hemorrhage leading to death. Review of the literature identified 124 cases of VADA involving the PICA origin described over the past decade. The methods of surgical and endovascular treatment of these cases were reviewed, with particular focus on the rationale of treatment, outcomes, and complications.

Conclusion

Numerous treatment options for VADA involving PICA have been reported with different risk and benefit profiles. Flow-diverting stents appear to offer the most favorable balance of securing the aneurysm and avoiding medullary infarction, but the risks and optimal anti-thrombotic treatment strategy are incompletely understood. In select cases, in which the surgical risk is low or in which the anatomy is favorable (e.g., nondominant parent vessel or robust collateral circulation in the involved territories), parent artery trapping with or without microsurgical revascularization can be considered.

Flow Alteration Therapy for Ruptured Vertebral Artery Dissecting Aneurysms Involving the Posterior Inferior Cerebellar Artery

Surgery for- and endovascular treatment of vertebral artery (VA) dissecting aneurysms involving the origin of the posterior inferior cerebellar artery (PICA) remain challenging. Their ideal treatment is complete isolation of the aneurysm by surgical or endovascular trapping plus PICA reconstruction. However, postoperative lower cranial nerve palsy and medullary infarction are potential complications. We report four patients with VA dissecting aneurysms involving the PICA origin who were treated by occipital artery (OA)-PICA bypass followed by proximal occlusion of the VA and clip ligation of the PICA origin instead of trapping. There were no procedural or ischemic complications. In all patients, angiography performed 2–3 weeks later showed good patency of the bypass graft and complete obliteration of the aneurysm. During the follow-up period ranging from 1 to 14 years, none experienced bleeding. Although retrograde blood flow to the dissecting aneurysm persisted in the absence of trapping, iatrogenic lower cranial nerve injury could be avoided. The decrease in aneurysmal flow might elicit spontaneous thrombosis and prevent aneurysmal rerupture. Our technique might be less invasive than aneurysmal trapping and help to prevent rebleeding.

Pathophysiology of carotid-cavernous fistulas in vascular Ehlers-Danlos syndrome: a retrospective cohort and comprehensive review

Background

Vascular Ehlers-Danlos syndrome (vEDS) is a rare condition characterized by connective tissue fragility. Direct spontaneous carotid-cavernous fistula (sCCF) is reportedly pathognomonic of vEDS. We conducted this study to understand the possible mechanisms of occurrence of sCCF in this subset of patients.

Methods

We conducted a retrospective analysis of a monocentric vEDS cohort along with a literature review regarding sCCF in this condition.

Results

Of 133 patients regularly followed in our centre between 2000 and 2017, 13 (9.8%) had a diagnosis of direct sCCF (92.3% female, median age 33.0 years, interquartile range (IQR) [26.0–39.5]). There were 7 Glycine missense and 6 splice-site variants but no variant leading to haploinsufficiency. The literature search identified 97 vEDS patients with direct sCCF (79.4% female, 7.2% sex not reported, median age 31.0 years, IQR [24.0–39.0]). Increased carotid circumferential wall stress, higher carotid distensibility and lower carotid intima-media thickness could contribute to a higher risk for direct sCCF in vEDS. There is no predictive factor for the occurrence of sCCF apart from female sex in vEDS.

Conclusions

In vEDS, anatomical and pathophysiological features of the intra-cavernous internal carotid artery make it prone to shunting in the cavernous sinus, due either to a spontaneous rupture or to a spontaneous dissection with pseudoaneurysm formation. Direct sCCF in seemingly healthy young individuals should be highly suggestive of vEDS and prompt further investigation.

Comparison of Endovascular Treatments of Ruptured Dissecting Aneurysms of the Intracranial Internal Carotid Artery and Vertebral Artery with a Review of the Literature

Objective

Subarachnoid hemorrhage (SAH) caused by rupture of an internal carotid artery (ICA) or vertebral artery (VA) dissecting aneuryesm is rare. Various treatment strategies have been used for ruptured intracranial dissections. The purpose of this study is to compare the clinical and angiographic characteristics and outcomes of endovascular treatment for ruptured dissecting aneurysms of the intracranial ICA and VA.

Methods

The authors retrospectively reviewed a series of patients with SAH caused by ruptured intracranial ICA and VA dissecting aneurysms from March 2009 to April 2014. The relevant demographic and angiographic data were collected, categorized and analyzed with respect to the outcome.

Results

Fifteen patients were identified (6 ICAs and 9 VAs). The percentage of patients showing unfavorable initial clinical condition and a history of hypertension was higher in the VA group. The initial aneurysm detection rate and the percentage of fusiform aneurysms were higher in the VA group. In the ICA group, all patients were treated with double stent-assisted coiling, and showed favorable outcomes. In the VA group, 2 patients were treated with double stent-assisted coiling and 7 with endovascular trapping. Two patients died and 1 patient developed severe disability.

Conclusion

Clinically, grave initial clinical condition and hypertension were more frequent in the VA group. Angiographically, bleb-like aneurysms were more frequent in the ICA group and fusiform aneurysms were more frequent in the VA group. Endovascular treatment of these aneurysms is feasible and the result is acceptable in most instances.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Endovascular Treatment in Ruptured Middle Cerebral Artery Dissection Preservation of Arterial Continuity

Rupture of spontaneous dissecting aneurysms of the middle cerebral artery (MCA) is rare and its etiology remains obscure, although the risk of rebleeding is greater than with saccular aneurysms. Most reports concerning the treatment of a ruptured dissecting aneurysm of the anterior circulation involve surgical trapping or wrapping. Here, we report on a case of an MCA dissecting rupture treated with endovascular procedures. A 22-year-old female presented with sudden stuporous mental change following severe headache and left side hemiparesis. A computed tomography scan showed a diffuse subarachnoid hemorrhage and diffusion MR showed diffusion restriction at the right putamen and internal capsule. A 3-hour follow-up digital subtraction angiography (DSA) showed a dissecting aneurysm, which was not seen on an initial DSA. A stent assisted coil embolization was performed and double stents were applied to achieve flow diversion effects. A small remnant area of the dissecting aneurysm had disappeared at 60-day and was not observed on 12-month follow-up DSA.

Clinical characteristics of symptomatic vertebral artery dissection: a systematic review

BACKGROUND

Vertebral artery dissection (VAD) is an important cause of stroke in the young. It can present nonspecifically and may be misdiagnosed with adverse consequences. We assessed the frequency of head/neck pain, other neurological symptoms, and cerebrovascular events in symptomatic VAD.

METHODS

We conducted a systematic review of observational studies, searching electronic databases (MEDLINE, EMBASE) for English-language manuscripts with >5 subjects with clinical or radiologic features of VAD. Two independent reviewers selected studies for inclusion; a third adjudicated differences. Studies were assessed for methodological quality, and clinical data were abstracted. Pooled proportions were calculated.

RESULTS

Of 3996 citations, we screened 511 manuscripts and selected 75 studies describing 1972 VAD patients. The most common symptoms were dizziness/vertigo (58%), headache (51%), and neck pain (46%). Stroke was common (63%), especially with extracranial dissections (66% vs. 32%, P<0.0001), whereas transient ischemic attack (14%) and subarachnoid hemorrhage (10%) were uncommon. Subarachnoid hemorrhage was seen only with intracranial dissections (57% vs. 0%, P=0.003). Fewer than half of the patients had obvious trauma, and only 7.9% had a known connective tissue disease. Outcome was good (modified Rankin scale 0 to 1) in 67% and poor (modified Rankin scale 5 to 6) in 10% of patients.

CONCLUSIONS

VAD is associated with nonspecific symptoms such as dizziness, vertigo, headache, or neck pain. Ischemic stroke is the most common reported cerebrovascular complication. VAD should be considered in the diagnostic assessment of patients presenting with dizziness or craniocervical pain, even in the absence of other risk factors. Future studies should compare clinical findings as predictors in well-defined, undifferentiated populations of clinical VAD suspects.

Management of middle cerebral artery dissecting aneurysm

BACKGROUND

Dissecting aneurysms of the intracranial carotid circulation were previously thought to occur primarily in young people presenting with cerebral infarction caused by arterial stenosis and occlusion. The appropriate management of dissecting aneurysms in the anterior circulation remains controversial, especially in patients who also present with cerebral infarction. However, recent studies have reported better outcomes for patients with middle cerebral artery (MCA) dissecting aneurysms involving surgically treated subarachnoid hemorrhage (SAH). The purpose of this study is to describe a case of spontaneous SAH from rupture of a dissecting aneurysm in the M2 segment observed in a 79-year-old man with no sign of an ischemic neurological deficit, and also to review the clinical and radiological features of cases reported since 1990.

METHODS

Our review of the literature identified 24 cases of MCA dissecting aneurysms after 1990.

RESULTS

Of the patients in these cases, 15 (63%) presented with pure bleeding and 7 (29%) with ischemia, and two were detected incidentally. Our review also found that the outcome of patients presenting with pure bleeding differed from those with ischemia. Patients with an MCA dissecting aneurysm who presented with pure bleeding showed better outcomes if they had surgery than if they did not. In contrast, the appropriate management of patients with a dissecting aneurysm who present with ischemia remains controversial.

CONCLUSION

Our review found that the clinical course of patients presenting with ischemia differed from that of patients presenting with pure bleeding. Most of the patients with ischemia underwent progressive deterioration. However, while the outcome for patients with ischemia treated surgically was relatively good, it remained poor compared to the outcome for patients who had been bleeding.

Long-term outcome of endovascular reconstruction with the Pipeline embolization device in the management of unruptured dissecting aneurysms of the intracranial vertebral artery

Object

Use of a flow-diverting device has shown promising short-term results in the management of vertebral artery (VA) dissecting aneurysms, but there is still uncertainty regarding its long-term efficacy and safety. The authors report their initial experience with respect to the potential utility and long-term clinical outcomes of using a flow-diverting device in the treatment of unruptured dissecting VA aneurysms.

Methods

The authors conducted a retrospective review of all cases of unruptured intracranial VA dissecting aneurysms treated at their institution (Tuen Mun Hospital) with a flow-diverting device. They describe the clinical presentations and angiographic features of the cases and report the clinical outcome (with modified Rankin Scale [mRS] scores) at most recent follow-up, as well as results of the latest angiographic assessment, with particular focus on in-stent patency and side-branch occlusion.

Results

A total of 4 aneurysms were successfully obliterated by using flow-diverting devices alone. Two devices were deployed in a telescoping fashion in each of 2 aneurysms, whereas only 1 device was inserted in each of the other 2 aneurysms. No periprocedural complication was encountered. No patient showed any angiographic evidence of recurrence, in-stent thrombosis, or side-branch occlusion in angiographic reassessment at a mean of 22 months after treatment (range 18–24 months). As of the most recent clinical follow-up (mean 30 months after treatment, range 24–37 months), all patients had favorable outcomes (mRS Score 0).

Conclusions

Reconstruction using a flow-diverting device is an attractive alternative in definitive treatment of dissecting VA aneurysms, demonstrating favorable long-term clinical and angiographic outcomes and the ability to maintain parent artery and side-branch patency. It is particularly useful in cases with eloquent side-branch or dominant VA involvement.

Dissecting aneurysms of the vertebral artery--angiographic patterns at the dissecting site on balloon test occlusion

Introduction

At present, the risk of future hemorrhage or ischemic insult from vertebral artery (VA) dissection cannot be estimated from available imaging data. We investigated the relationship between symptoms and the angiographic patterns of the dissecting site on balloon test occlusion (BTO) to develop guidelines for clinical decision-making.

Methods

We retrospectively reviewed 18 patients with unilateral VA dissection who presented with subarachnoid hemorrhage (SAH) or cerebral infarction. We analyzed the angiographic findings at the dissecting site on contralateral VA angiograms during BTO of the affected VA, classified the angiographic patterns into two types, and compared the symptoms they presented.

Results

Patients with dissection opacified from the distal to the proximal side are more likely to present with cerebral infarction than SAH. Conversely, patients with dissection opacified from the proximal to the distal side had a significantly higher incidence of SAH.

Conclusions

Angiographic findings at the dissecting site on contralateral VA angiograms during BTO of the affected VA are helpful for considering the treatment and prognosis of patients with VA dissecting aneurysms.

Craniocervical arterial dissection in children: diagnosis and treatment

OPINION STATEMENT

Diagnosis of craniocervical arterial dissection (CCAD) in children begins with a careful history and physical in a child with a transient ischemic attack (TIA) or arterial ischemic stroke (AIS). The extent of radiologic evaluation for suspected CCAD is based upon careful consideration of the risks associated with the best imaging techniques, weighed against the benefits of enhanced vascular imaging with better diagnostic sensitivity. Although conventional angiography (CA) and CT angiography (CTA) have a higher sensitivity than magnetic resonance angiography (MRA), they are accompanied by risks: for CA, femoral hematoma, femoral arterial pseudoaneurysm, recurrent AIS, and radiation exposure; for CTA, radiation. For children (non-neonates) with suspected CCAD, MRI with MRA is recommended as the first-line imaging study. MRI usually includes diffusion-weighted, FLAIR, and T1 images of the brain, and T1 or T2 fat-saturation axial imaging through the neck. MRA should include 3D time-of-flight MRA of the head and neck (from the aortic arch through the circle of Willis). Contrast-enhanced MRA should be highly considered in neck imaging. If MRI/MRA is equivocal, CCAD is strongly suspected but not detected on MRI/MRA (especially in the posterior circulation), or the child has recurrent events, additional imaging of the craniocervical vasculature is likely warranted. Individual clinical circumstances warrant careful, case-by-case consideration. Treatment of CCAD in children is challenging and differs for intracranial and extracranial dissections. In extracranial CCAD, we most commonly use anticoagulation for 6 weeks to 6 months in patients with TIA or AIS. Typically, unfractionated heparin is used in the acutely ill patient at heightened risk for bleeding (because of its short half-life), whereas low-molecular-weight heparin (LMWH) or warfarin are reserved for the stable patient. If the history is suspicious for dissection (head and neck trauma, recent cervical chiropractic manipulation, recent car accident, or neck pain), we consider treatment for dissection even with normal MRI/MRA. For patients with CCAD with a stroke size greater than one third to one half of the middle cerebral artery territory (or other bleeding risk factors) and extracranial CCAD, in whom there is concern about heightened risk for hemorrhagic conversion, we commonly use aspirin therapy during the acute phase. Regardless of their treatment in the initial weeks to months, we subsequently treat all patients with aspirin for 1 year after their event, and sometimes longer if they have other risk factors. Interventional techniques, such as extracranial cerebral arterial stent placement or selective occlusion, are understudied in children. Interventional techniques are typically reserved for patients who fail aggressive medical management and have recurrent TIA or AIS. The diagnosis and treatment of intracranial dissection is extraordinarily challenging in children, in whom inflammatory intracranial arteriopathies are common. When intracranial arteriopathy is clearly associated with dissection, the clinician should look for the presence of subarachnoid hemorrhage and/or dissecting aneurysm. Treatment decisions should be made by a multidisciplinary pediatric stroke team, given the lack of data in this area. Intracranial cerebral artery stent placement carries high risk and is not recommended for intracranial CCAD in children. Most importantly, we educate all children with CCAD and their parents about the paucity of evidence in the treatment of this disease, the risks of enhanced imaging techniques such as CTA or CA, and the challenges involved in weighing the risks of aggressive therapies and interventions against the costs of unclear diagnosis and potentially ineffective treatments. We also educate our patients with CCAD about the signs and symptoms of recurrence and the importance of emergent evaluation.

Management of ruptured and unruptured intracranial vertebral artery dissecting aneurysms

Vertebral artery dissecting aneurysms (VADA) are challenging disorders for neurosurgeons. Between December 2005 and May 2010, we treated 12 patients for DA of the intracranial VA. Three were treated by open surgery, seven underwent endovascular manipulation, and two were conservatively managed. Nine patients presented with subarachnoid hemorrhage from the ruptured aneurysm, and of these, two experienced abrupt re-hemorrhage and three presented with symptoms of brainstem ischemia. One of the two patients with a re-hemorrhage underwent conservative management and died in hospital of re-bleeding at 30 days after initial presentation. No postoperative neurological deficits occurred in patients treated by open surgery or via an endovascular approach. No re-hemorrhage or ischemic symptoms were observed in the 11 remaining patients during the mean 29-month (range: 14-54-month) follow-up. The chosen management strategy should be developed according to the patient's clinical condition and imaging results. Endovascular treatment, which includes several techniques, is the first choice for most patients.

The use of motor evoked potential monitoring during cerebral aneurysm surgery to predict pure motor deficits due to subcortical ischemia

Subcortical infarcts are most commonly the consequence of perforating artery occlusion and pure motor deficit is the most frequent syndrome resulting from an interruption of the corticospinal tract at the level of the corona radiate, the internal capsule or the brainstem. Motor evoked potential (MEP) monitoring is used as an adjunct to surgery as somatosensory evoked potentials (SEP) have been found to be insensitive to these lesions. Two different techniques have been used for monitoring MEPs during aneurysm surgery: transcranial electrical stimulation (TES) and direct cortical stimulation (DCS). TES may result in patient movement, interfering with microdissection. There is also concern that TES MEP may not detect subcortical motor pathway ischemia by stimulating deeper subcortical structures and may thereby bypass the ischemic area. DCS produces focal muscle activation, less movement and more superficial stimulation that should detect cortical and superficial subcortical ischemia, hence avoiding false-negatives. However, this technique also has disadvantages including subdural bleeding and injury to the brain. Using close-to-motor-threshold stimulation and focal stimulating electrode montages, TES and DCS MEPs do not vary significantly in their capacity to detect lesions of the motor cortex or its efferent pathways. Both techniques are prone to interference by anesthetic agents.

Endovascular treatment of ruptured dissecting vertebral artery aneurysms--long-term follow-up results, benefits of early embolization, and predictors of outcome

INTRODUCTION

The purpose of this study was to evaluate the effect of endovascular treatment of ruptured dissecting aneurysms of the vertebral artery, the benefits of early embolization, and the predictors of outcomes.

CLINICAL MATERIAL AND METHODS

Between September, 2001 and May, 2009, 25 patients with ruptured vertebral dissecting aneurysms were treated by internal coil trapping (n = 23) or stents (n = 2) in our hospital. There were 14 males and 11 females with a mean age of 45 years (age range, 22-66 years). Dissecting aneurysms were supra-posterior inferior cerebellar artery lesions (n = 16), infra-posterior inferior cerebellar artery lesions (n = 6), or involved the posterior inferior cerebellar artery (n = 3).

RESULTS

Complete occlusion of dissected arterial and aneurysm segments (internal trapping) was achieved in 21 (91.3%) of 23 patients. The two patients with posterior inferior cerebellar artery involvement underwent double stent only placement. Clinical outcomes were favorable in 17 (68%) of 25 patients, 2 (8%) had severe disability, and 6 (24%) patients died. Risk factors that varied with favorable versus unfavorable outcomes were: preoperative Hunt-Hess, World Federation of Neurological Surgeons scale, presence of hydrocephalus, presence of lateral medullary syndrome, presence of low cranial nerve palsy, rebleeding, time of endovascular procedures, and time from admission to procedure. However, univariate Cox analysis confirmed that only low preoperative Hunt-Hess grade predicted favorable clinical outcome. Early embolization did not affect clinical outcome, but reduced the risk of rebleeding and inpatient stay.

CONCLUSION

In our experience, internal trapping of the dissected segment with a coil was straightforward, applicable to most patients, prevented rebleeding safely and effectively without significant procedural complications, and had a good follow-up outcome. The low Hunt-Hess grade remained predictors of favorable clinical outcomes. The timing of embolization did not significantly affect clinical outcome but early embolization reduces inpatient stay.

A study of vertebrobasilar artery dissection with subarachnoid hemorrhage

We retrospectively studied clinical characteristics of 368 patients with cerebral artery dissections who were diagnosed in 172 Japanese hospitals. Of these patients, 130 (35%) presented with subarachnoid hemorrhage, 217 (59%) with cerebral infarctions, and 21 (6%) with transient ischemic attacks. We analyzed 109 (84%) subarachnoid hemorrhage cases caused by vertebrobasilar artery dissection to evaluate conservative and surgical treatment from the viewpoint of postoperative rerupture and infarction.Subsequent ruptures were observed in 14% of the 21 cases with nonsurgical treatment. For the preventive purpose of rerupture, 88 patients received surgical interventions: 68 trappings, 13 proximal occlusions, 6 aneurysmal sac occlusions and 1 stenting. Rerupture was experienced in 33% of the aneurysmal sac occlusion patients while not occurring in the other three surgical interventions. In the group without vascular anastomosis, postoperative cerebral infarction was observed in 25% of the trapping, none of the proximal occlusion and 33% of the aneurysmal sac occlusion cases.In this study, aneurysmal sac occlusion treatments were more frequently complicated by rerupture or cerebral infarction postoperatively than the other treatment methods. It was difficult to determine which surgical treatment can achieve better surgical outcome among the proximal occlusion and trapping with or without vascular anastomosis.

Successful endovascular reconstruction of acutely ruptured pseudoaneurysm of the vertebral artery, complicated by isolated vertebrobasilar circulation and symptomatic vasospasm

The management of a ruptured pseudoaneurysm of intracranial vertebral artery (VA), which is the sole supplier to an isolated vertebrobasilar system, is challenging. The authors report on such a case in a 49-year-old man who suffered a grade III subarachnoid hemorrhage (SAH) caused by a dissecting fusiform pseudoaneurysm of the left VA. The right VA terminated in the posterior inferior cerebellar artery and posterior communicating arteries were absent. The patient developed symptoms consistent with vasospasm on day 9 after SAH, which was treated by intra-arterial vasolytic therapy, followed by stent placement and "in-stent" balloon angioplasty. Angiography 2 weeks later showed near-complete resolution of the pseudoaneurysm. At discharge, the patient's modified Rankin score was one. In this complicated case in which an isolated vertebrobasilar circulation precluded parent vessel sacrifice, we detail the successful management using a combination of intra-arterial vasolytic therapy, stent reconstruction, and balloon angioplasty.

Endovascular strategies for vertebrobasilar dissecting aneurysms

BACKGROUND AND PURPOSE

Dissecting vertebrobasilar aneurysms are challenging to treat, and standard treatment modalities remain controversial. We retrospectively evaluated our experience using endovascular techniques to treat these aneurysms.

MATERIALS AND METHODS

From February 1997 to December 2007, 42 patients with intradural vertebrobasilar dissecting aneurysms underwent endovascular treatment. Twenty-nine patients had ruptured aneurysms, and 13 patients had unruptured dissecting aneurysms. The endovascular modalities for vertebrobasilar dissecting aneurysms were the following: 1) trapping (n = 30), 2) proximal occlusion (n = 3), 3) stent with coil (n = 6), and 4) stent alone (n = 3).

RESULTS

Seventeen of the 29 patients with ruptured vertebrobasilar dissecting aneurysms had successful outcomes without procedural complications following endovascular treatment. Procedure-related complications were the following: 1) rebleeding (n = 3), 2) posterior inferior cerebellar artery (PICA) territory infarction (n = 6), 3) brain stem infarction (n = 2), and 4) thromboembolism-related multiple infarctions (n = 1). Clinical outcomes were favorable in 32 patients (76.1%). There were 3 (7.1%) procedure-related mortalities due to rebleeding, and 1 (2.4%) non-procedure-related mortality due to pneumonia sepsis. All 13 patients with unruptured vertebrobasilar dissecting aneurysms had favorable clinical and radiologic outcomes without procedure-related complications.

CONCLUSIONS

Endovascular procedures for treatment of unruptured symptomatic dissecting aneurysms resulted in favorable outcomes. Ruptured vertebrobasilar dissecting aneurysms are associated with a high risk of periprocedural complications. Risks can be managed by using appropriate endovascular techniques according to aneurysm location, configuration, and relationship with the PICA.

Management of posterior fossa dissecting aneurysms

SUMMARY

Treatment and prognosis of 14 patients of posterior fossa arterial dissections (AD) and dissecting aneurysms (DA) in one institution was reviewed. Internal trapping of aneurysm was performed for six patients presenting with SAH (three Vertebral, one posterior cerebral, one posterior inferior cerebellar, one anterior inferior cerebellar DA). The patency of the parent arteries was preserved in four DA patients with SAH (two Vertebral, two Basilar DA), 1 incidental vertebral DA, and one DA patient with brainstem infarction using stents and coils (four patients) or coils only (two patient). Proximal occlusion of parent artery was performed in a vertebral DA with SAH. One patient with a superior cerebellar DA presented with a midbrain infarct developed SAH with spontaneous occlusion of the aneurysm two weeks later. Of the 14 cases, ten were angiographically stable or cured during a follow up period of four to 70 months. one spontaneously resolved and two recurred. There was one death.

Idiopathic aneurysms of distal cerebellar arteries: endovascular treatment after rupture

INTRODUCTION

Idiopathic ruptured aneurysms of distal cerebellar arteries (DCAAs) are rare, and their endovascular therapy (EVT) has as yet not been extensively reported. They are usually assumed to result from local arterial wall disruption rather than infection, unlike distal supratentorial artery aneurysms. This study was performed to audit their frequency, potential aetiology and results of EVT.

PATIENTS AND METHODS

Using strict inclusion criteria and a database of 1715 EVT patients, we identified ten idiopathic ruptured DCAAs (0.6%) over a 13-year period (1993-2006). The series comprised six males and four females with mean age of 64 years and solitary aneurysms located on posterior inferior cerebellar artery (five patients), anterior inferior cerebellar artery (three patients) and superior cerebellar artery (two patients). Nine aneurysms were fusiform and were treated by endovascular parent artery occlusion, and one was saccular and treated by endosaccular packing. Endovascular therapy was performed with coils in seven cases, n-butyl-2-cyanoacrylate (NBCA) in two cases and with both in one case.

RESULTS

Primary EVT was successful in eight patients. One patient died following a procedure-related re-bleeding and one patient required re-treatment after failed endosaccular packing. Nine patients made good or excellent clinical recoveries (modified Rankin Scale 2 or less). Focal cerebellar infarctions were seen on computed tomography images after EVT in three patients, only one of whom was symptomatic with transient dysmetria, which resolved completely during follow up. No aneurysm recanalisation was detected on late follow-up imaging up to 24 months.

CONCLUSION

Ruptured DCAAs are rare. The majority are fusiform in shape and their aetiology remains uncertain. Endovascular treatment is feasible and effective. It usually requires parent artery occlusion.

Blood flow disturbance in perforating arteries attributable to aneurysm surgery

Object

The object of this study was to investigate patients with cerebral infarction in the area of the perforating arteries after aneurysm surgery.

Methods

The authors studied the incidence of cerebral infarction in 1043 patients using computed tomography or magnetic resonance imaging and the affected perforating arteries, clinical symptoms, prognosis, and operative maneuvers resulting in blood flow disturbance.

Results

Among 46 patients (4.4%) with infarction, the affected perforating arteries were the anterior choroidal artery (AChA) in nine patients, lenticulostriate artery (LSA) in nine patients, hypothalamic artery in two patients, posterior thalamoperforating artery in five patients, perforating artery of the vertebral artery (VA) in three patients, anterior thalamoperforating artery in nine patients, and recurrent artery of Heubner in nine patients. Sequelae persisted in 21 (45.7%) of the 46 patients; 13 (28.3%) had transient symptoms and 12 (26.1%) were asymptomatic. Sequelae developed in all patients with infarctions in perforating arteries in the area of the AChA, hypothalamic artery, or perforating artery of the VA; in four of five patients with posterior thalamoperforating artery involvement; and in two of nine with LSA involvement. The symptoms of anterior thalamoperforating artery infarction or recurrent artery of Heubner infarction were mild and/or transient. The operative maneuvers leading to blood flow disturbance in perforating arteries were aneurysmal neck clipping in 21 patients, temporary occlusion of the parent artery in nine patients, direct injury in seven patients, retraction in five patients, and trapping of the parent artery in four patients.

Conclusions

The patency of the perforating artery cannot be determined by intraoperative microscopic inspection. Intraoperative motor evoked potential monitoring contributed to the detection of blood flow disturbance in the territory of the AChA and LSA.

Spontaneous dissecting aneurysm of the intracranial vertebral artery: management strategies

PURPOSE

Pathogenesis and treatment of spontaneous dissecting aneurysm of the intracranial vertebral artery (VA) remain controversial. This study was designed to provide management strategies and to improve management outcome in patients with these aneurysms.

MATERIALS AND METHODS

Among a total of 1,990 patients treated for intracranial aneurysms from February 1992 to June 2005, 28 patients (1.4%) were treated either by surgery (8 patients) or neurointervention (20 patients) for spontaneous dissecting aneurysms of the intracranial VA. Twenty-two patients had ruptured aneurysms. We analyzed indications of surgery or neurointervention for each case, and assessed the management outcome at a 6-month follow-up.

RESULTS

For selection of therapeutic options, patients were initially evaluated as possible candidates for neurointervention using the following criteria: 1) poor clinical grade; 2) advanced age; 3) medical illness; 4) unruptured aneurysm; 5) equal or larger opposite VA; 6) anticipated surgical difficulty due to a deep location of the VA-posterior inferior cerebellar artery (PICA) junction. Surgery was considered for patients with: 1) high-risk aneurysms (large or irregular shaped); 2) smaller opposite VA; 3) failed neurointervention; or 4) dissection involving the PICA. Management outcomes were favorable in 25 patients (89.3%). Causes of unfavorable outcome in the remaining 3 patients were the initial insult in 2 patients, and medical complications in one patient.

CONCLUSION

Ruptured aneurysms must be treated to prevent rebleeding. For unruptured aneurysms, follow-up angiography would be necessary to detect growth of the aneurysm. Treatment modality should be selected according to the clinical characteristics of each patient and close collaboration between neurosurgeons and neurointerventionists is essential.

Incidence of Ischemic Complications after Endovascular Treatment for Ruptured Dissecting Vertebral Artery Aneurysms. Comparison between Those Arising Proximal to and Distal to the Origin of the Posterior Inferior Cerebellar Artery

SUMMARY

We analyzed the incidence of ischemic complications after internal trapping for ruptured VA dissecting aneurysms. Between April 2001 and August 2005, nine cases of ruptured VA dissecting aneurysms, five in women, "proximal" or distal (distal type) to the origin of the PICA, were treated by internal trapping in the acute stage after SAH. There were four cases of proximal type and five of distal type. The demographics of the patients were reviewed in the medical charts and radiological findings were evaluated by neuroradiologists. The dissected site was completely obliterated and PICA was preserved in all cases. Follow-up angiography performed five to 19 days after treatment revealed complete obliteration of the aneurysm and patency of the PICA. The incidence of perioprocedural ischemic complications for the PICA-distal type (75%) was higher than that for the PICA-proximal type (20%). Here we retrospectively analyzed and discussed the incidence and mechanisms of ischemic complications.

Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment

Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.

Endovascular treatment of ruptured vertebral dissecting aneurysms with electrodetachable coils

BACKGROUND

Ruptured intradural vertebral dissecting aneurysm (VDA) is associated with a high risk of rebleeding and a high incidence of mortality if left untreated because of its natural history. We report our experience of endovascular treatment of ruptured VDAs using electrodetachable coils.

METHODS

Over 7 years, 10 patients with spontaneously ruptured intradural VDAs were managed by endovascular embolization in our institute. All patients received endovascular trapping of the dissecting aneurysm and proximal occlusion by electrodetachable coils.

RESULTS

There were 5 men and 5 women, with a mean age of 48 years. Of the 10 VDAs, 8 were located in the supra-posterior inferior cerebellar artery (PICA) area, and 2 were in the infra-PICA area. Six affected vertebral arteries were dominant (n = 3) or co-dominant (n = 3) in the vertebrobasilar system. Nine ruptured VDAs and their parent arteries were successfully occluded by a single session of endovascular embolization by electrodetachable coils. In the tenth patient, the dissecting aneurysm showed subtotal occlusion because of involvement of the vertebrobasilar junction. The mean number and coil length were 7 and 58 cm, respectively. There were no significant periprocedural complications or recurrent bleeding. All patients demonstrated good clinical recovery (n = 9) or improvement (n = 1) after embolization over a mean follow-up of 15 months (range, 6-24 months).

CONCLUSION

Endovascular embolization is a useful and safe method in the treatment of ruptured VDAs even when the affected vertebral arteries are dominant or co-dominant in vertebrobasilar flow. Trapping procedures and direct occlusion of the dissecting segment with preservation of the PICA by detachable coils should be performed as early as possible in the management of VDAs.

Treatment of Intra- and Extracranial Arterial Dissections Using Stents and Embolization

PURPOSE

To evaluate the safety and efficacy of stent placement for extracranial and intracranial arterial dissections.

METHODS

Eighteen patients underwent endovascular treatment of carotid and vertebral dissections using intraluminal stent placement. Five patients with arterial dissection were treated, 2 using one insertion of a single stent and 3 using placement of two stents. Patients with a dissecting aneurysm were treated as follows: 7 patients with insertion of one stent, 4 with placement of two stents, and 2 by stent-assisted Guglielmi detachable coil embolization. In the 18 patients in whom stenting was attempted, the overall success in reaching the target lesion was 94.4%. Of the 17 patients treated with stents, stent release and positioning were considered optimal in 16 (94%) and suboptimal in one (6%). In patients who underwent a successful procedure, all parent arteries were preserved. There were no instances of postprocedural ischemic attacks, new neurologic deficits, or new minor or major strokes prior to patient discharge. In follow up, all patients were assessed, using the modified Rankin scale, as functionally improved or of stable clinical status. The reduction in dissection-induced stenosis or pseudoaneurysm, the patency rate obtained at follow-up, and the lack of strokes (ischemic or hemorrhagic) suggest that stent placement offers a viable alternative to complex surgical bypass or reconstructive procedures. The long-term efficacy and durability of stent placement for arterial dissection remain to be determined in a larger series.

[Intracranial extension of extracranial vertebral artery dissections. A review of 16 cases]

INTRODUCTION

Vertebral artery (VA) dissections can involve both the extracranial and intracranial portions of the VA. Intradural extension explains the occurrence of subarachnoid hemorrage (SAH). We have studied the rate of this extension, the risk of associated SAH and the therapeutic repercussions at the acute stage.

METHODS

From 1985 to 2001, 42 patients with a recent extracranial VA dissection were admitted to our department of neurology. When the diagnosis of extracranial VA dissection (involving the first, second or third segment of the VA) was established, we looked for an ipsilateral intracranial extension (involving the fourth segment of the VA and/or the basilar artery). VA dissections strictly located at the intracranial level were excluded.

RESULTS

Among 42 patients with angiographically diagnosed extracranial VA dissections, 16 patients (38 percent) had an ipsilateral intradural extension. Two of them developed an inaugural and spontaneous SAH. After a mean follow-up of 4 Months under antithrombotic treatment, none of the patients has developed SAH or recurrent SAH.

CONCLUSIONS

Because of the potential risk for spontaneous SAH at the acute stage, it seems important to exclude an intracranial extension. Lumbar puncture should be undertaken to exclude SAH before consideration of antithrombotic therapy.

Rebleeding of a vertebral artery dissecting aneurysm during stent-assisted coil embolization: a pitfall of the “stent and coil” technique

BACKGROUND

A stent-assisted coil embolization has been applied as a novel choice of treatment for vertebral artery dissecting aneurysms (VADAs).

CLINICAL PRESENTATION

A 45-year-old man suffered from subarachnoid hemorrhage three times within 2 hours. The left vertebral angiogram showed a VADA at the distal origin of the posterior inferior cerebellar artery. The right vertebral artery was hypoplastic, and collateral circulation to the posterior fossa was poor.

INTERVENTION

Stent-assisted coil embolization was performed under general anesthesia. The aneurysm was excluded from the circulation with good patency of the vertebral artery, although the fourth coil caused rebleeding from the aneurysmal dome during the procedure.

CONCLUSION

This is the first case report that demonstrates rebleeding from VADA during stent-assisted coil embolization in the acute stage of its rupture. We have to be aware of the risks and be ready to prevent fatal complications with this novel technique.

Spontaneous fusiform middle cerebral artery aneurysms: characteristics and a proposed mechanism of formation

OBJECT

The goal of this study was to identify the origins of spontaneous fusiform middle cerebral artery (MCA) aneurysms.

METHODS

One hundred two cases of spontaneous fusiform MCA aneurysms were reviewed, including 40 from the authors' institutions and 62 identified from the literature. The mean age at symptom onset was 38 years, and the male/female ratio was 1.4:1. At presentation, the MCA lumen was stenosed or occluded in 12 patients, focally dilated in 57, and appeared "serpentine" in 33. Most lesions originated from the M1 or M2 segments, and most (80%) presented with nonhemorrhagic symptoms or were discovered incidentally. The presenting clinical features correlated with morphological findings in the aneurysms, which could be observed to progress from a small focal dilation or vessel narrowing to a serpentine channel. Hemorrhage was the most common presentation in small lesions; the incidence of bleeding progressively diminished with larger lesions. Patients with stenoses or occluded vessels most often presented with ischemic symptoms, and occasionally with hemorrhage. Giant focal dilations or serpentine aneurysms were rarely associated with acute bleeding; clinical presentation was most often prompted by mass effect or thromboembolic stroke.

CONCLUSIONS

Analysis of results after various treatments indicates that for symptomatic lesions, therapies that reverse intraaneurysmal blood flow and augment distal cerebral perfusion are associated with better outcomes than other strategies, including conservative management. Based on the spectrum of clinical, pathological, neuroimaging, and intraoperative findings, dissection is proposed as the underlying cause of these lesions.

Isolated dissections and dissecting aneurysms of the posterior inferior cerebellar artery: topic and literature review

Isolated dissections of the posterior inferior cerebellar artery (PICA) are rare. Thus, no large series of cases have been reported in the literature. Due to limited knowledge regarding the natural history of these lesions and the lack of high-quality evidence supporting various treatment options, management is controversial and practice parameters are ill defined. In order to offer a comprehensive reference for the diagnosis and management of isolated PICA dissections, the authors reviewed the National Library of Medicine from 1966 to October 2001. Twenty-seven patients averaging 43.6 years of age and including 14 males and 13 females were reported. Subarachnoid hemorrhage occurred in 20 patients, and two died. Dissections were located in the proximal PICA in 22 patients and were three times more common on the left side (left:right=3:1). Six patients were managed conservatively, and four with endovascular techniques. Seventeen had open surgery: five underwent resection, two went through trapping, and two had proximal clipping. Wrapping with muscle was performed in two patients, encasement with Sundt clips in two, and four had occipital artery (OA)-PICA bypass surgery. A meticulous analysis of reported cases with regard to clinical and pathological features, management strategies, and outcomes is presented.

Dissecting aneurysms of the middle cerebral artery: neuroradiological and clinical features

There are few reported cases of nontraumatic dissecting aneurysms of the middle cerebral artery (MCA), and their neuroradiological and clinical features have not been analysed. We looked at these aspects in a collaborative study. We reviewed 13 patients diagnosed as having a dissecting aneurysm of the MCA based on clinical signs and neuroradiological findings in 46 stroke centres between 1995 and 1999. There were four patients who presented with cerebral ischaemia, and nine who presented with bleeding. Of the former group, three were aged less than 15 years. Cerebral angiography showed extensive stenosis and a double lumen of the M1 portion in all four patients. High signal on T1-weighted images around the arterial flow void, due to intramural haematoma, was often seen in the second week. MR angiography showed findings corresponding those of intra-arterial angiography in all four cases. We saw an infarct on CT or MRI in territory of the perforating branches of the M1 segment in all four patients. In the patients presenting with bleeding, pure subarachnoid haemorrhage or a sylvian fissure haematoma was seen on initial CT, and the predominant angiographic finding was dilatation with stenosis, but the site of the lesions was not uniform. A double lumen or intimal flap was seen in about half the cases. Rebleeding occurred within 14 days of the onset in five of the nine patients, with a poor prognosis.

Subarachnoid hemorrhage caused by a dissecting aneurysm of the internal carotid artery

Object. Subarachnoid hemorrhage (SAH) caused by the rupture of a dissecting aneurysm of the internal carotid artery (ICA) has been considered rare. Based on data from cooperatively collected cases, the clinical features of patients with dissecting aneurysms of the ICA who presented with SAH were examined.

Methods. Data from 18 patients with dissecting aneurysms of the ICA who presented with SAH diagnosed on the basis of clinical signs, neuroradiological findings, and intraoperative findings from 41 institutions were collected during a 5-year period between 1995 and 1999. The authors found that 0.3% of all cases of SAH and 3.1% of cases of SAH of unverified cause were attributable to a dissecting aneurysm of the ICA. Eleven patients (61%) were middle-aged women, and eight patients (44%) had hypertension. Rebleeding before admission was demonstrated in 13 patients (72%), and intraoperative bleeding was exhibited in half of the patients who underwent surgery during the acute stage. Postoperative growth of an aneurysm bulge or recurrent SAH was seen in five of 10 patients who had undergone wrapping or clipping of the aneurysm bulge in the acute phase. Trapping with or without bypass, which resulted in no postoperative recurrence, was performed in three patients in the acute stage and in two patients in the chronic stage. Twelve patients (67%) had a poor prognosis, primarily attributed to intraoperative bleeding and postoperative recurrence.

Conclusions. Generally, dissecting aneurysms of the ICA are not thought of as frequent causes of SAH. Nonetheless, the presence of these aneurysms should be considered when dealing with SAH because they have a susceptibility to bleeding that can lead to a poor prognosis. Careful surgical planning is necessary to decrease intraoperative bleeding and to avoid postoperative recurrence.

Dissecting aneurysms of the vertebral artery: a management strategy

OBJECT

The authors present a retrospective analysis of their experience in the treatment of vertebral artery (VA) dissecting aneurysms and propose a management strategy for such aneurysms, with special emphasis on the most formidable VA dissecting aneurysms, which involve the origin of the posterior inferior cerebellar artery (PICA).

METHODS

Since 1998, 18 patients with VA dissecting aneurysms, 11 of whom presented with subarachnoid hemorrhage (SAH), have been treated by endovascular surgery at the authors' institution. Obliteration of the entire segment of the dissected site with coils (internal trapping) was performed for aneurysms without involvement of the origin of the PICA (12 cases; among these the treatment-related morbidity rate was 16.7%). The treatment strategy applied to PICA-involved VA dissecting aneurysms presenting with SAH (three cases) included proximal occlusion of the parent artery followed by internal trapping of the aneurysm (one case), proximal occlusion of the parent artery followed by occipital artery (OA)-PICA bypass (one case), and two-staged internal trapping of the aneurysm involving double PICAs (one case). For PICA-involved VA dissecting aneurysms that were not associated with SAH at presentation (three cases), OA-PICA bypass was performed and followed by internal trapping of the aneurysm (two cases). In the remaining case in which a fetal-type posterior communicating artery was present, internal trapping was performed following successful balloon test occlusion (BTO). Overall, there was no sign of infarction in the PICA territory, despite complete occlusion of aneurysms involving the PICA. There was no recurrent bleeding or ischemic symptoms during the follow-up periods. The overall treatment-related morbidity rate for the VA dissecting aneurysms involving the PICA was 16.7%.

CONCLUSIONS

Dissecting VA aneurysms that do not involve the PICA can be safely treated by internal trapping. For those lesions that do involve the PICA, a decision-making algorithm is advocated to maximize the efficacy of the treatment as well as to minimize the risks of treatment-related morbidity based on BTO.

Vertebrobasilar dissection: a possible role of whiplash injury in its pathogenesis

We reviewed 29 patients with vertebrobasilar dissections (VBD) to investigate the correlation between minor trauma and VBD and the clinical features of this trauma-related condition. Mean age was 43 years, with a male predominance (male/female ratio was 25/4). Seventeen patients presented with subarachnoid hemorrhage (SAH), and 12 with ischemic symptoms. Two patients presenting with ischemia had extracranial VBD (V3 segment). Angiographically, aneurysmal dilatation was observed in most SAH patients (13 patients) in contrast to narrowing or occlusion in most ischemic patients (10 patients). Among the 12 SAH patients treated with coil embolization or conservatively, five died, whereas all ischemic patients recovered well with anticoagulation and/or antiplatelet therapy. Seven patients had received minor or trivial head/cervical trauma, due to whiplash injury, minor fall, or during exercise, which were identified to precede with the lapse of some time (a few minutes or days) the onset of symptoms. All of these patients presented with ischemic symptoms, and they were younger than the other ischemic or SAH patients. The site of vertebral artery dissection was intracranial in four cases, extracranial in one case, and combined in two cases at the level of the V3 segment and the origin of the posterior inferior cerebellar artery. However, no SAH occurred. These clinicopathological findings, i.e. ischemia and angiographic narrowing/occlusion, suggest that dissections were subintimal. Therefore, it is believed that this minor or trivial trauma may primarily cause subintimal dissection with luminal compromise, leading to ischemic symptoms, rather than subadventitial or transmural dissection with aneurysmal dilatation, leading to SAH. This lesion may also occur in younger patients with a favorable outcome. Careful note should be made of patient for the early recognition of this disorder.