Intracranial dissecting aneurysms of the posterior circulation. Report of six cases and review of the literature

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

We reviewed 24 patients with intracranial vertebral artery dissections treated during the last 12 years. Sixteen patients were admitted with subarachnoid hemorrhage (SAH) and 8 did not have SAH. The mean age at the time of onset was 50.0 years. Male preponderance was noted. Among 21 patients with acute onset, 6 (29%) experienced prodromal neck pain and 3 (60%) of 5 SAH patients showed nuchal stiffness when examined within 6 hours of onset. The preoperative angiographical findings were uniform in SAH cases in contrast to the varied angiographical findings seen in non-SAH cases. So-called pearl and string sign was observed in most SAH cases, but the "string" was often so short and wide that the term "constriction" appeared more suitable. From intraoperative observations, the angiographical point of constriction seemed to represent the proximal or distal end of dissection. As for treatment, 19 patients underwent 20 surgeries. Trapping was performed in eight surgeries, base clipping was performed in five, and proximal clipping was performed in seven. Both trapping and base clipping prevented further bleeding, but trapping was associated with a high rate of postoperative lower cranial nerve palsy. Postoperative neurological complications were less frequent after proximal clipping, but subsequent postoperative bleeding occurred in one patient treated by this technique. The overall long-term outcome in the surgically treated cases in our series was favorable, but most patients suffered from various degrees of uncomfortable dysphagia or hoarseness for some period after surgery. It was also noted that, in half of the disabled cases, the major disability was attributable to lower cranial nerve palsy and respiratory troubles that developed postoperatively.

Nonsurgical treatment of unruptured intracranial vertebral artery dissection with serial follow-up angiography

The question of whether unruptured intracranial vertebral artery dissections should be treated surgically or nonsurgically still remains unresolved. In this study, six consecutive patients with intracranial vertebral artery dissection presenting with brain-stem ischemia without subarachnoid hemorrhage (SAH) were treated non-surgically with control of blood pressure and bed rest, and five received follow-up review with serial angiography. No further progression of dissection or associated SAH occurred in any of the cases, and all patients returned to their previous lifestyles. In the serial angiograms in five patients, the findings continued to change during the first few months after onset. Four cases ultimately showed "angiographic cure," while fusiform aneurysmal dilatation of the affected vessel persisted in one case. In one patient, arterial dissection was visualized on the second angiogram despite negative initial angiographic findings. These results indicate that intracranial vertebral artery dissection presenting without SAH can be treated nonsurgically, with careful angiographic follow-up monitoring. Persistent aneurysmal dilatation as a sequela of arterial dissection seemed to form a subgroup of fusiform aneurysms of the posterior circulation. These aneurysms may be prone to late bleeding and may require surgical treatment.

Management of dissecting aneurysms of the posterior circulation

We analysed the clinical presentation, treatment and outcome of our own 36 cases of posterior circulation dissecting aneurysms (DA) and discussed the surgical indications and procedures regarding posterior fossa DA. Twenty one cases were male, 15 cases were female. Their mean age was 54 +/- 14 years. Clinical manifestations were subarachnoid haemorrhage (SAH) in 14 cases (39%) and ischaemic attacks in 22 cases (61%). Three of 14 SAH cases had rebleeding in the acute stage. Angiographic findings were aneurysmal dilatation in 16 cases, retention of contrast medium in 12 cases, string sign in 9 cases, double lumen in 4 cases, pearl and string sign in 3 cases, and occlusion of parent artery in 2 cases. Surgical treatment was performed on nineteen cases (53%). The operation was carried out in the acute stage on the SAH group; in the subacute or chronic stage on the ischaemic group. The surgical procedure was the proximal ligation, trapping and removal of DA with or without revascularization of the parent artery. 84% of the surgically managed patients and 71% of the nonsurgical cases had a favourable outcome (good recovery or moderate disability). Poor prognosis was revealed from the rebleeding and primary neurological stage. We recommend surgical treatment in the acute stage on the SAH group. On the ischaemic group surgical treatment in the subacute or chronic stage is recommended, if the DA has the risk of rupture or progression of the dissection.

Extracranial-intracranial saphenous vein bypass for carotid or vertebral artery dissections: a report of six cases

The management of carotid or vertebral artery dissections has generally been either conservative (with anticoagulation) or surgical (by proximal ligation or trapping procedures). However, identification and management of those patients with a high risk of stroke recurrence have been difficult. Six patients with carotid or vertebral artery dissections underwent a total of seven surgical procedures involving intracranial interpositional saphenous vein bypass grafts anastomosed distally beyond the point of dissection with trapping of the intermediate diseased section of the artery. It is suggested that this procedure be used in patients who have bilateral carotid or vertebral artery disease, persistent angiographic abnormalities (particularly aneurysms), or recurring ischemic events while undergoing anticoagulation therapy, or in whom anticoagulation is undesirable. This procedure has benefits over current surgical options because of the maintenance of high flow, the avoidance of abnormal watershed areas of flow, and the elimination of the risk of emboli. The procedure is compared to previous techniques of extracranial-intracranial bypass.

Dissecting aneurysms of the vertebrobasilar system: study of 16 cases

In the last 14 years we have encountered 16 patients with spontaneous intracranial dissections of the vertebrobasilar (VB) system (mean age was 46 years and male/female ratio was 10/6). VB dissections presented in eight cases with subarachnoid bleeding and in eight with brainstem, cerebellar, or cerebral ischemia. Three patients had multiple dissections. Ten dissections occurred in the vertebral artery (two extended to the basilar artery), three in the posterior cerebral artery (one bilateral), two in the basilar artery, and one in the posterior inferior cerebellar artery. The angiographic configuration included "string" sign, "pearl and string" sign, fusiform dilation, and double lumen. The following angiographic evolution (available in 11 cases) was that of complete healing (three cases), partial resolution (five cases), progression (one case), and unimproving (two cases). Three patients died (two due to recurrent subarachnoid hemorrhage): two patients were explored surgically (one had further intravascular therapeutic embolization), and the rest were treated conservatively. Not all dissecting aneurysms fared in the same manner, depending either on the location in the VB circulation or on the variable vascular configuration: treatment should be fitted to the timing of diagnosis.

Dissecting aneurysm of the posterior inferior cerebellar artery: case report

A patient with a dissecting aneurysm of a posterior inferior cerebellar artery who presented with Wallenberg's syndrome is reported. A 31-year-old man suddenly experienced an occipital headache, vertigo, and vomiting, followed by dysphagia. A neurological examination revealed partial Wallenberg's syndrome. Vertebral angiography revealed aneurysmal dilatation at the origin of the left posterior inferior cerebellar artery, with distal luminal narrowing. T1-weighted magnetic resonance imaging demonstrated an area of high-signal intensity, indicating an intramural hemorrhage in the arterial wall of the narrowed lumen. The dissecting aneurysm with a typical intramural hematoma of the posterior inferior cerebellar artery was entrapped with clips after an anastomosis of the left occipital artery to the distal posterior inferior cerebellar artery. The diagnosis and the treatment of dissecting aneurysms of the posterior inferior cerebellar artery are discussed.

A pathological study of intracranial posterior circulation dissecting aneurysms with subarachnoid hemorrhage: report of three autopsied cases and review of the literature

Three autopsied cases of dissecting aneurysms with spontaneous subarachnoid hemorrhage of the intracranial posterior circulation are reported, and the literature is reviewed to investigate the pathological characteristics and pathogenesis of this lesion. The location and pathological features of the aneurysms were different in each of the cases presented. Subadventitial hemorrhage associated with the subarachnoid hemorrhage, multiple noncontiguous intramural hemorrhages, and new vessels in and around the arterial wall were noteworthy findings in our series. All 20 reported autopsied cases of the vertebrobasilar artery have a dissection between the media and adventitia with a rupture site in the thin adventitia. Seventeen of them had disruption of the entire arterial wall, but the remaining three cases had no apparent luminal connection. The clinicopathological features of this disease are various. On the basis of the pathological investigations of these reported cases, the pathogenesis of this lesion is discussed. Intramural hemorrhage associated with dissection without luminal connection should not be disregarded as a causative factor.

Endovascular treatment of vertebral artery dissections and pseudoaneurysms

Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.

Recurrent ischemic events in two patients with painless vertebral artery dissection

BACKGROUND AND PURPOSE

Vertebral artery dissection causes endothelial changes and stenosis that may lead to recurrent ischemic neurological events. The diagnosis may not be obvious because the dissection may be painless and "spontaneous" (no obvious trauma). Magnetic resonance angiography has increasingly been used to screen patients for this disorder, but its accuracy has not yet been established.

CASE DESCRIPTION

Two patients were admitted with repeated transient ischemic attacks and strokes over 11 months and 1 month, respectively. Neither had a history of trauma, cervical pain, or headache. Magnetic resonance angiography failed to visualize vertebral artery dissections that were later revealed by conventional angiography. One patient's events were stopped by balloon occlusion of the vertebral artery proximal to the posterior inferior cerebellar artery branch.

CONCLUSIONS

Magnetic resonance angiography is not yet sensitive enough to always visualize vertebral artery dissection. Vertebral artery dissection is a life-threatening condition that requires aggressive evaluation and treatment.

"Dolichoectatic" intracranial vertebrobasilar dissecting aneurysm

We report five patients with intracranial vertebrobasilar dissecting aneurysms, all of whom had ischemic symptoms. Angiographically, four of the five cases revealed distention and elongation of the vertebrobasilar artery like dolichoectasia and one irregular stenosis, the so-called "string sign". Magnetic resonance imaging disclosed all dolichoectatic dissecting lesions by demonstrating intimal flaps, double lumen, or subacute clot in the false lumen. We also present a successful demonstration of slow flow in the false lumen by gradient refocused magnetic resonance imaging scan with partial flip angle by the cardiac gating method. It is suggested that many of the classical "dolichoectasia" may include dissecting lesions.

[Intracranial dissecting aneurysms of the posterior circulation: report of 3 cases and review of the literature]

Dissecting aneurysms of cerebral arteries are unusual causes of stroke. The carotid system is the commonest site of this pathology, the vertebral arteries are less involved and dissection of the basilar artery is rare. The authors report three cases of arterial dissection of the vertebrobasilar system, two of the vertebral arteries and one of the basilar artery. An extensive review of the literature is presented. The clinical picture of dissection of vertebrobasilar system was inespecific but pain was a prominent symptom, though had not occurred in the site of the arteries involved. The pain was suggestive of subarachnoid hemorrhage. Associated or risk factors were mild trauma, migraine and high blood pressure. The angiographic findings were suggestive, however just the "double lumen" has been considered pathognomonic. The prognosis is variable. It was benign in case 3, left sequela in case 2, and case 1 rebleed fatally.

Subarachnoid hemorrhage following spontaneous intracranial carotid artery dissection

Subarachnoid hemorrhage due to spontaneous dissection of intracranial vessels is uncommon. Most such cases are confined to the posterior circulation. Dissection of an intracranial carotid artery producing subarachnoid hemorrhage without a focal ischemic event is rarely documented. We report a case and review the subject.

Postpartum dissecting aneurysm of the basilar artery

BACKGROUND AND PURPOSE

Dissecting aneurysms arising from the vertebrobasilar complex are rare and difficult to manage. More of their natural history needs to be known before treatment can be optimized.

CASE DESCRIPTION

We report a postpartum dissecting aneurysm of the right vertebrobasilar artery in a 31-year-old woman that was confirmed by angiographic identification of a double lumen. The intracranial segment of the right vertebral artery was thrombosed proximal to the aneurysm. The patient, managed conservatively, recovered well and, when reexamined 2 months later, was found to be neurologically intact. A repeat angiographic study at that time demonstrated that the aneurysm had resolved.

CONCLUSIONS

Proximal occlusion may have protected the aneurysm from rupture and further dissection, thereby making surgery unnecessary.

Dissection of cranial arteries in the neck: correlation of MRI and arteriography

Retrospective correlation of MRI and angiographic findings in nine patients with suspected cervical vascular dissections revealed MRI evidence of vessel abnormalities in eight patients, seven of whom proved to have arterial dissections. One patient whose MRI showed no abnormalities also proved to have a dissection, shown by angiography. Two patients had associated pseudoaneurysms not demonstrated by MRI. Five dissections involved the carotid arteries and three the vertebral arteries. Seven of the nine patients had associated transient neurologic deficits, while two had permanent deficits. Frank infarction of the brain was demonstrated by MRI in five cases. MRI findings suggestive of dissection included: (1) increased signal from the entire vessel; (2) a border of increased signal surrounding the lumen, with luminal narrowing; (3) poor or absent visualization of the vessel; and (4) significant compromise of the vessel lumen by adjacent abnormal increased signal tissue.

Proximal clipping and bypass between bilateral vertebral arteries using a radial arterial graft for the treatment of a dissecting aneurysm of the vertebral artery

Proximal clipping has been performed recently as the main surgical treatment for a dissecting aneurysm of the vertebral artery. When there is a contralateral vertebral artery of a smaller size with arteriosclerotic changes, some form of bypass to prevent cerebellar and brain stem infarction is needed in addition to proximal clipping. We treated a 50-year-old man with a ruptured dissecting aneurysm of the left vertebral artery and stenosis at the V3 segment of the right vertebral artery. The caliber of the right vertebral artery was smaller than the left. After an anastomosis between bilateral vertebral arteries using a radial arterial graft, dissecting aneurysm was clipped at the proximal portion of the aneurysm.

A clinicopathological study of dissecting aneurysms of the intracranial vertebral artery

Five autopsied cases of dissecting aneurysms of the intracranial vertebral artery are reported and the literature is reviewed to clarify the clinicopathological correlations. In an autopsy series of 110 patients with subarachnoid hemorrhage (SAH), the incidence of this entity was 4.5%, with all five cases progressing rapidly to death from massive SAH. Cases of intracranial vertebral dissection can be divided clearly into two groups based on the clinical and pathological features. In the first group, the dissection is confined to the vertebral artery and a massive SAH develops caused by the rupture of the arterial wall. The plane of dissection is mainly subadventitial. In the second group, brain-stem infarction develops resulting from luminal occlusion by intramural hematoma. The plane of dissection is mainly subintimal, with the dissection extending to the basilar artery. The condition in the second group affects patients at a younger age. If the lesion is localized within the vertebral artery and does not extend to the basilar artery, the disease seems not to be fatal. The clinical features of the vertebral dissection are largely determined by the plane and extension of dissection. Vertebral artery dissection is due to many causative factors including hypertension, congenital or degenerative changes in the arterial wall, and anatomical and pathological characteristics of the vertebral artery.

Spontaneous dissecting aneurysms of the basilar artery presenting with a subarachnoid hemorrhage. Report of two cases

A spontaneous dissecting aneurysm of the basilar artery is a rare disorder, usually presenting with ischemia rather than a subarachnoid hemorrhage (SAH). Two cases are described of a dissecting aneurysm of the basilar artery presenting with an SAH. Vertebral angiography revealed a double lumen to the basilar artery. Magnetic resonance (MR) imaging detected the intramural hematoma. One patient was treated conservatively, and the other underwent operative intervention with wrapping of the aneurysm. The usefulness of MR imaging in the diagnosis and the treatment options are discussed.

Benign arterial dissections of the posterior circulation

Four young adults with spontaneous dissection of the vertebrobasilar system are reported. Clinically, two patients presented with subarachnoid hemorrhage and two with brain-stem ischemia. In two cases of ruptured arterial dissection of the posterior cerebral artery, angiography demonstrated fusiform and "sausage-like" dilatation of the involved vessel. In two cases of occlusive dissection of the basilar artery, angiography revealed the typical "string sign." All four patients were treated conservatively: three survive in good clinical condition and one remains disabled. Follow-up angiograms showed spontaneous healing of the lesion with return to an almost normal arterial configuration in two cases; residual narrowing corresponding to the dissection was the most notable finding in the other two. It is recommended that, in a subset of neurologically stable patients, angiographic monitoring is undertaken to assess the tendency for spontaneous repair before surgical intervention is planned.

Hemifacial spasm caused by a spontaneous dissecting aneurysm of the vertebral artery. Case report

The authors describe the first reported case of dissecting aneurysm presenting with hemifacial spasm. The patient was a 58-year-old woman with left hemifacial spasm of 2 years' duration. Cranial nerve examination was otherwise normal and no other clinical symptoms were observed. Vertebral angiography revealed a fusiform enlargement of the left vertebral artery and contrast medium remaining in the intramural false lumen in the venous phase. Microvascular decompression of the facial nerve with wrapping of the aneurysm resulted in complete relief of the hemifacial spasm.

Subarachnoid hemorrhage from a dissecting aneurysm of the middle cerebral artery. Case report

A case of subarachnoid hemorrhage (SAH) from a dissecting aneurysm of the inferior limb of the middle cerebral artery is reported. The patient's clinical status and the initial and follow-up angiographic appearance of the aneurysm are presented. Diagnosis and treatment are briefly discussed. It is suggested that, if angiography demonstrates luminal narrowing or vascular occlusion in a patient with unexplained SAH, a dissecting aneurysm of the carotid system should be considered as a cause of the hemorrhage.

Three cases of spontaneous extracranial vertebral artery dissection

We describe three cases of extracranial vertebral artery dissection that are unusual in both their modes of presentation and their associations with other pathologic conditions. The first patient had Marfan's syndrome and migraine; his dissection was asymptomatic and was diagnosed by chance at the time of repeat angiography following a previous internal carotid artery dissection. The second patient had systemic lupus erythematosus and presented with a subarachnoid hemorrhage attributed to an intracranial vertebral artery dissection by the demonstration of an extracranial dissection. The third patient had a minor basilar artery stroke in which dissection had occurred beside a congenital hemivertebra deformity.

Proximal clipping of dissecting intracranial vertebral aneurysm--effect of balloon Matas test with neurophysiological monitoring. Case report

A case of repeated subarachnoid haemorrhage (SAH) caused by rupture of a dissecting intracranial vertebral aneurysm is reported. The clinical manifestations, angiographic findings, pre-operative assessment with neurophysiological monitoring, and surgery are presented. A review of the literature suggests that this type of intracranial aneurysm is being recognized with increasing frequency in SAH and fatality, and therefore exploration and treatment of vertebrobasilar (V-B) dissecting aneurysms is necessary. We emphasize that a balloon Matas test with monitoring of somatosensory evoked potentials (SEP), auditory brain stem responses (ABR), and its wedge pressure in occluding the vertebral artery before operation are objective assessments of treatment for dissecting intracranial vertebral aneurysm.

Dissecting aneurysms of the intracranial vertebral artery

Among 86 patients with aneurysms arising from the vertebral artery or its branches, 24 had dissecting aneurysms. The patients with dissecting aneurysms were characteristically relatively young males. Twenty-one patients presented with subarachnoid hemorrhage (SAH) and three with ischemia. Severe headache or neck pain occurred in all three patients with ischemia. Five of the 21 patients with SAH and all three patients with ischemia experienced recurrent episodes. Angiography typically showed fusiform dilatation and proximal and/or distal narrowing of the affected artery. The difficulty of diagnosing this disorder is pointed out. Surgery was performed in 19 patients, the most common technique being clip-occlusion of the proximal vertebral artery. There were no postoperative deaths or rebleeding; a lateral medullary syndrome developed in three patients. The observation at surgery of intramural clot with characteristic discoloration was limited to the cases operated on within 36 days after the ictus. After this period, the aneurysm was whitish gray in color and had become firm. Of 36 other cases of vertebral dissecting aneurysm reported in the literature, 20 were operated on. The indications for surgery are discussed.

Dissecting and fusiform aneurysms of vertebro-basilar systems. MR imaging

The magnetic resonance (MR) findings of three cases with vertebro-basilar dissecting aneurysms (DA) were compared with those of two cases with vertebro-basilar fusiform aneurysms (FA). No abnormal findings, excepting a dilatation of a signal-void area corresponding to the arterial blood flow, were shown on the MR images in the patients with a FA. In contrast to the FA cases, various abnormalities were detected by the MR studies in all three DA cases. An intimal flap and a double lumen were demonstrated in one case. An intra-mural hematoma was shown in one case. A hematoma neighboring the parent artery was demonstrated in two cases. MR imaging was thought to be useful for detecting intracranial vascular lesions, such as a DA, and for discriminating between a DA and a FA.

Non-traumatic dissecting aneurysms of the intracranial vertebral artery. Report of six cases

We present 6 cases with dissecting aneurysm of the intracranial vertebral artery who developed subarachnoid haemorrhage (SAH). The following procedures were performed in this series; trapping of the involved artery in 2, proximal occlusion of the vertebral artery with detachable balloon in 2, and proximal clipping of the vertebral artery in 2. Proximal occlusion of the vertebral artery in 4 and trapping of the vertebral artery in one gave excellent results. We believe the treatment of choice is proximal occlusion of the vertebral artery, either by open surgery or by interventional neuroradiological procedures.

Diagnosis and treatment of vertebral aneurysms

The intracranial vertebral artery and its branches are a common site of aneurysms in the posterior fossa. Ninety-four aneurysms in 86 patients were analyzed for their clinical manifestation, diagnosis, and treatment. There were three distinct varieties of aneurysm in this group: 56 (60%) saccular aneurysms, 26 (28%) dissecting aneurysms, and 12 (13%) atherosclerotic fusiform aneurysms. Of the 26 dissecting aneurysms, 81% bled and 24% of these rebled. None of the atherosclerotic fusiform aneurysms bled. Angiographic differentiation between dissecting aneurysms and atherosclerotic fusiform aneurysms was difficult. The dissecting aneurysms were characterized by a "narrowed segment" proximal and/or distal to a "fusiform dilatation" of the affected artery and by the presence of contrast medium in the intramural false lumen until the late phase. Poor postoperative outcome and the lateral medullary syndrome were seen only in dissecting aneurysms. Small atherosclerotic fusiform aneurysms seemed to be benign lesions that do not require any surgical treatment.

Subarachnoid hemorrhage presenting as acute chest pain: a variant of le coup de poignard

A 39-year-old woman presented to the emergency department with symptoms of acute knifelike chest pain and was discharged with a diagnosis of musculoskeletal pain syndrome. One day later, she returned with a complaint of persistent chest pain. Physical examination disclosed meningismus, this led to a lumbar puncture and the subsequent diagnosis of subarachnoid hemorrhage. Angiography later revealed findings consistent with dissection of the vertebral artery. This case illustrates an unusual presentation and cause of spinal subarachnoid hemorrhage, a potentially treatable emergency condition.

Dissecting aneurysms of the vertebral arteries following cervical manipulation: a case report

Neck manipulation may uncommonly be associated with serious and even fatal vascular complications. Although well recognised, the nature of the vascular injury has only rarely been directly established by pathological examination. The case is reported of a 43-year-old man who died following neck manipulation, and in whom multiple dissecting aneurysms within both vertebral arteries were demonstrated radiologically and found at necropsy. Bilateral dissecting aneurysms were found both at the level of atlanto-axial articulation and close to the origins of the vertebral arteries. No predisposition was found, other than early atheroma consistent with the patient's age.