Neurovascular neurosurgery

Neurovascular disorders including brain aneurysms, arteriovenous malformations (AVMs) and intracranial atherosclerotic disease with its associated morbidity and mortality has a significant health and economic toll on our population. They form a major part of the neurosurgical work load. Neurovascular or vascular neurosurgery covers a wide variety of conditions: intracerebral haemorrhage, subarachnoid haemorrhage, cerebral aneurysms, atherosclerotic and non-atherosclerotic cerebrovascular disease, vascular malformations, both cranial and spinal, to name some. The aim of this article is to outline the more commonly encountered neurovascular conditions, their diagnosis and management, to better equip those looking after patients with neurovascular conditions.     

Vascular anomalies and subarachnoid haemorrhage associated with persisting embryonic vessels

Summary In 25 per cent of patients with persistinc primitive trigeminal artery, and in 27 percent of patients with primitive hypoglossal artery, vascular malformations or a history of subarachnoid haemorrhage were found. There is a high incidence of aneurysms at the site of origin of the persisting embryonic vessels. No relation was found between the persisting embryonic vessels and the age, sex, and time of subarachnoid haemorrhage. Opacification of posterior cerebral arteris, vertebral arteries, and posterior communicating arteries was analysed, and variations of the Circulus arteriosus Willisi were found. Ten patients with persisting embryonic vessels are described. In patients in whom external carotid—middle cerebral artery bypass is planned, attention should be drawn to the possibility of persisting embryonic vessels.Dedicated to Prof. Dr. Dr. h. c. H. W. Pia on the occasion of his 60th anniversary.     

Anaesthesia for neurovascular surgery and the management of ischaemic stroke

Neurovascular anaesthesia covers the preoperative period, during which resuscitation and stabilization are crucial, the treatment of the lesion, either in the operating theatre or radiology suite, and the postoperative treatment which aims to reduce long-term morbidity. Throughout these periods care involves assuring adequate oxygenation and perfusion to the area of brain injury, as well as reducing the incidence of re-bleeding and other complications. Therapeutic procedures for intracranial aneurysms usually consist of either surgical clipping or endoscopic coiling before or after a subarachnoid haemorrhage. Embolization, radiosurgery, surgical excision or a combination of these modalities is used to treat arteriovenous malformations (AVMs). Most haematoma following intracranial haemorrhage are evacuated surgically, depending on the location of the haematoma and the clinical condition of the patient.     

Ependymoma of conus medullaris presenting as subarachnoid haemorrhage

Summary Subarachnoid haemorrhage (SAH) due to spinal ependymoma is very rare. We report a 37 year old man who presented with typical clinical signs of SAH. Lumbar puncture confirmed SAH but cerebral angiography was negative, and further diagnostic work-up revealed an ependymoma of the conus medullaris as the source of the haemorrhage. A comprehensive review of the literature was conducted. Only 17 patients with spontaneous SAH due to a spinal ependymoma have been reported since 1958. However, in cases of SAH and negative diagnostic findings for cerebral aneurysms or malformations, this aetiology should be considered and work-up of the spinal axis completed. Correspondence: Christian T. Ulrich, Neurosurgical Clinic, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany.     

Clinical features of the haemorrhage type moyamoya disease based on 31 cases

Summary We evaluated and analysed our own 31 cases of the haemorrhagic type of moyamoya disease to clarify the clinical features of this disease. The cases were divided into three groups. Group A consisted of 12 cases with aneurysms. Aneurysms on the circle of Willis were treated as ordinary saccular aneurysms. Group B consisted of 14 cases with intracerebral haemorrhage (ICH) without aneurysms. These were managed almost as spontaneous ICH. Group C consisted of 5 cases with intraventricular haemorrhage (IVH) without aneurysms or ICH. Twenty-two surgical procedures for aneurysms, ICH and IVH were done in 19 cases (62%). Nineteen procedures for preventing future strokes were undertaken in 11 cases (35%). The overall initial outcome was excellent in 12 cases (39%), good in 7 cases (23%), poor in 7 cases (23%), and death in 5 cases (15%). During the follow-up period (mean: 6.5 years), rebleeding occurred in two cases (8%), and ischaemic attacks in two cases (8%). The rate of rebleeding or ischaemic attacks was 1.19% per patient-year during the follow-up period. There was no ischaemic or rebleeding episode in cases treated by STA-MCA bypass with encephalomyosynagiosis (EMS) during the follow-up period. Management of the primary haemorrhage should be according to the clinical condition, type of haemorrhage, and source of haemorrhage. When the patient needs to undergo revascularization surgery to prevent future strokes, we recommend STA-MCA bypass with EMS instead of encephaloduro-arteriosynangiosis (EDAS).     

Aneurysm of the internal auditory artery: Our experience and review of the literature

Summary The aneurysms of the internal auditory artery (IAA) situated distal from anterior inferior cerebellar artery (AICA)-IAA junction, are extremely rare lesions. A case of distal aneurysm of IAA is presented causing subarachnoid haemorrhage (SAH) and complete ipsilateral deafness. After the neurosurgical treatment the hearing of the patient definitely improved. The literature of distal aneurysms of AICA is reviewed focusing on the clinical features of these malformations, causing cerebello-pontine angle (CPA) symptoms with or without SAH.     

Spontaneous intracerebellar haematoma

Summary The authors report ten cases of spontaneous intracerebellar haematoma diagnosed by computed tomography. They emphasize the role of CT scanning in the management of patients with cerebellar haemorrhage, while vertebral angiography excludes the presence of vascular malformations (aneurysms or angiomas).     

Influence of aneurysm location on the development of chronic hydrocephalus following SAH

Summary The incidence of chronic hydrocephalus was analysed in a series of 204 patients with aneurysmal subarachnoid haemorrhage (SAH). Its development was significantly related to the quantity of subarachnoid blood, but even more to the location of the haemorrhage and to the aneurysm site. Hydrocephalus was more frequent in patients under poor initial condition. Whereas intracerebral haemorrhage did not increase the risk of chronic cerebrospinal fluid (CSF) resorption disturbances, patients with intraventricular haemorrhage or voluminous haemorrhage in the basal cisterns have a significantly higher risk of such a complication. In this series 30 (15%) patients developed chronic hydrocephalus and required shunting. Surprisingly, in our series a shunt wasnever needed in patients with aneurysms of the middle cerebral artery (MCA). SAH from an aneurysm of the internal carotid artery (ICA) also never caused a shunt-dependent hydrocephalus except in cases with accompanying intraventricular haemorrhage. The percentage of chronic hydrocephalus was relatively high (19%) in patients with anterior communicating artery (ACoA) aneurysms but definitely highest in patients with an aneurysm of the vertebrobasilar (VB) system (53%).     

Application of CT Angiography of Complex Cerebrovascular Lesions during Surgical Decision Making

Helical computed tomographic angiography (CTA) is a relatively new noninvasive volumetric imaging technique. Since early reports in the 1990s, CTA has rapidly improved image resolution and scan volume. Cerebral arteries can be imaged clearly, which is advantageous in the diagnosis of vascular diseases such as cerebral aneurysms, arteriovenous malformations, and cerebrovascular occlusive disease. Before attacking a cerebrovascular lesion near or in the skull base, precise preoperative knowledge of anatomic relationships between the bony and neurovascular structures is critical for obtaining successful outcomes. The sensitivity of CTA for the detection of cerebral aneurysms < or = 5 mm in diameter may be higher than that of digital subtraction angiography (DSA), with equal specificity and high interoperator reliability. With minor modification to the technique, paraclinoid vascular lesions can be depicted using CTA. We present our experience using CTA in addition to DSA to obtain important anatomic information about skull base vascular lesions that assisted in the clinical decision-making process.     

Bilateral Wyburn-Mason syndrome presenting as acute subarachnoid haemorrhage – a very rare congenital neurocutaneuos disorder

A 30 year old young male was admitted to our department after experiencing clinical symptoms of a subarachnoid haemorrhage. Imaging studies revealed large cerebral AVMs. Fundus examination of the left eye demonstrated a retinal racemose AVM almost completely covering the posterior pole of the eye. Wyburn-Mason syndrome is a very rare congenital neurocutaneous disorder comprising of vascular malformations of the retina, ipsilateral cerebral AVMs and occasionally lesions in the oronasopharyngeal area. Subarachnoid haemorrhage associated with Wyburn-Mason syndrome has been described in only 5 patients in the literature since 1973. The finding of retinal AVMs should warrant cerebral imaging studies including CT- or MR-angiography.     

Cerebral Aneurysms in the Perforating Artery Manifesting Intracerebral and Subarachnoid Haemorrhage – Report of two Cases

BACKGROUND: An arteriosclerotic aneurysm in the perforating artery has been focused on as a causative factor for hypertensive intracerebral haemorrhage. However, its pathogenesis remains unknown, and its existence is still a controversy. CASE DESCRIPTION: A 62-year-old female and a 70-year-old male with a history of hypertension suffered from intracerebral haemorrhage accompanied by subarachnoid haemorrhage. Cerebral angiograms demonstrated an aneurysm arising from the perforating artery at the central location of the haematoma in both cases. The aneurysms were confirmed as the cause of bleeding during microsurgery, and were resected. Histological examination of the surgical specimens revealed that the walls of the aneurysms lacked internal elastic lamina and consisted only of the adventitia. CONCLUSION: These findings demonstrate that the aneurysm in the perforating artery can be a causative factor for hypertensive intracerebral haemorrhage, and indicate that the loss of internal elastic lamina induced by hypertension may contribute to the formation of the aneurysm of the perforating artery.     

Treatment of patients with spontaneous intracranial hematomas

Spontaneus intracerebral haemorrhage is a common cause of stroke especially in the young. The term "spontaneuos intracerebral haemorrhage" refers to bleeding without coincident trauma. About 80% of this haemorrhage occur supratentorial in the basal nuclei and they are associated with hypertension. Etiological factors range from congenital vascular malformations (aneurysmas, AVM, cavernomas) to acquired and degenerative vascular and brain conditions. In primary intracerebral hemorrhage arterial hypertension and consequent vascular changes are the major etiological factors. In secondary- nonhypertensive hemorrhage cause may be associated with aneurysms, AVM, tumors, coagulation disorders. Contemporary diagnosis imaging (CT, MRI) and neurological evaluation, allow early diagnosis and effective medical and/or surgical therapy in a majority patients. Without treatment, the risk of mortality and morbidity is high. Medical management involves normalization of blood pressure, reduction of intracranial pressure, control of brain edema and prevention of seizures. In design for operative treatment must be include age of the patient, hematoma size and location, clinical condition, the level of consciousness and patient outcome. The role of surgery remains contraversial.     

Screening for intracranial aneurysms in autosomal dominant polycystic kidney disease

SUMMARY:   Screening patients with autosomal dominant polycystic kidney disease (ADPKD) for asymptomatic intracranial aneurysms has been proposed as a method of reducing the morbidity and mortality associated with aneurysm rupture. However, recent studies have shown lower spontaneous rupture rates of small aneurysms and higher risks of significant complications with interventions than previously reported. Risk-benefit analysis has not demonstrated any benefit of screening ADPKD patients without a history of subarachnoid haemorrhage (SAH) for intracranial aneurysms, and has suggested that screening might cause harm.     

The Extreme Lateral Transcondylar Approach to Aneurysms of the Vertebrobasilar Junction, the Vertebral Artery, and the Posterior Inferior Cerebellar Artery

The unilateral suboccipital craniotomy is the commonly performed approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery (PICA). Many of these aneurysms are placed anterior or anterolateral to the brain stem, necessitating brain stem retraction for adequate exposure. Small dorsolateral enlargement of the foramen magnum, partial resection of the occipital condyle, and removal of the jugular tubercle allow access to the neurovascular structures ventral to the medulla without retraction of the neuroaxis. This extreme lateral transcondylar approach was performed in 20 patients with aneurysms of the vertebrobasilar junction, the vertebral artery, and the PICA; intraoperatively, two suspected aneurysms proved to be vascular malformations. Occlusion of the aneurysm and vascular malformation was successfully performed in 16 patients, resection of the vascular malformation was achieved in 1 patient, and the vertebral artery was clipped in 3 patients with fusiform aneurysms without complications related to the extreme lateral transcondylar approach. Unobstructed exposure of the aneurysm, parent artery, and neural structures without retraction of the sensitive lower brain stem are the major advantages of the extreme lateral transcondylar approach.     

The extreme lateral transcondylar approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery

The unilateral suboccipital craniotomy is the commonly performed approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery (PICA). Many of these aneurysms are placed anterior or anterolateral to the brain stem, necessitating brain stem retraction for adequate exposure. Small dorsolateral enlargement of the foramen magnum, partial resection of the occipital condyle, and removal of the jugular tubercle allow access to the neurovascular structures ventral to the medulla without retraction of the neuroaxis. This extreme lateral transcondylar approach was performed in 20 patients with aneurysms of the vertebrobasilar junction, the vertebral artery, and the PICA; intraoperatively, two suspected aneurysms proved to be vascular malformations. Occlusion of the aneurysm and vascular malformation was successfully performed in 16 patients, resection of the vascular malformation was achieved in 1 patient, and the vertebral artery was clipped in 3 patients with fusiform aneurysms without complications related to the extreme lateral transcondylar approach. Unobstructed exposure of the aneurysm, parent artery, and neural structures without retraction of the sensitive lower brain stem are the major advantages of the extreme lateral transcondylar approach.     

Intracranial Haemorrhage Within the First two Years of Life

Summary. Summary. Background: Spontaneous intracranial haemorrhage is not common in infants, with differences from adults in both aetiology and severity. The infantile CNS is more vulnerable because of incomplete hydrovenous maturation. We analyzed infantile intracranial haemorrhage mainly caused by structural brain lesions and discuss specific aetiologies with regard to haemodynamic characteristics. Subjects and Methods: We reviewed 20 infants less than 2 years of age from a total of 328 neonates and infants with intracranial vascular lesions seen in our institution since 1985. Associated or causative lesions were arteriovenous malformation (AVM) in 6, dural sinus malformation (DSM) in 4, arteriovenous fistula (AVF) in 3, aneurysm in 2, developmental venous anomaly (DVA) in 1, vein of Galen malformation (VGAM) in 1, and others in 3. The locations of haematomas were intracerebral (ICH) in 8, combined ICH and intraventricular haemorrhage (IVH) in 5, IVH alone in 5, subarachnoid haemorrhage (SAH) in 1, and combined SDH and ICH in 1. Findings: Three patterns of haemorrhage were noted in high-flow vascular lesions such as AVM or AVF (n=9); haemorrhage at the site of nidus or fistula corresponding to nidal pseudoaneurysm in 4, regional venous hypertension with pial venous reflux in 3, global venous infarction causing multifocal haemorrhage in distant brain areas in 2. Aneurysmal bleeds were caused by dissecting aneurysms at the level of dural penetration of cranial vessels. One infant had haemorrhage near a DVA without evidence of cavernous malformation suggesting the possibility of venous ischaemia. IVH was associated with shunt operations in 4 infants with DSM, and SDH followed by ICH in a infant with VGAM. Interpretation: Spontaneous intracranial haemorrhage in infants and neonates is rare; it is associated with specific lesions which show some differences from their adult counterparts. The vein-related causes of hemorrhage are largely the pathophysiologic characteristics in this age group. Absence of hemorrhage in VGAM is remarkable in addition to occurrence of most hemorrhages after shunting.     

Special remarks on microsurgical techniques for cerebral aneurysms

Summary Reviewing 152 cases of intracranial aneurysms which have been operated under identical preoperative, intraoperative and postoperative surgical conditions, the authors discuss the role of the microsurgical technique for prevention of postoperative vasospasm and for positively influencing the symptoms caused by subarachnoid haemorrhage.     

Hepatic artery aneurysm causing gastrointestinal haemorrhage – Case report and literature review

IntroductionTrue hepatic artery aneurysms (HAAs) are rare, and when complicated by gastrointestinal haemorrhage, it becomes an even rarer disease entity. The mortality is high and imaging may fail to provide the diagnosis. We present a case of a true hepatic artery aneurysm complicated by a fistula to the duodenum which was first recognised during surgery.Presentation of caseA 77-year-old man presented with upper gastrointestinal haemorrhage. Upper endoscopy revealed an ulceration in the duodenal bulb, which was refractory to endoscopic treatment. Computed tomography and angiography did not reveal the source of haemorrhage and as such, the diagnosis was delayed, until laparotomy was performed. Resection of the HAA and graft placement resulted in complete haemostasis.DiscussionTrue hepatic aneurysms communicating with the gastrointestinal tract have only been presented in case reports and short case series. Arteriosclerosis is a relatively common risk factor, but the underlying pathology is unknown. Meanwhile, gastrointestinal haemorrhage is a symptom of other, more common diseases in the gastrointestinal tract, and these factors, complicate the diagnostic workup.ConclusionIn the case of treatment refractory duodenal haemorrhage, a visceral aneurysm should be considered. Even though angiography is performed, a HAA may remain undetected due to bleeding cessation. Improved computed tomography modalities could aid in the detection of gastrointestinal haemorrhage from HAAs, and ensure timely treatment by endovascular methods or surgery if the diagnosis is kept in mind in the initial evaluation.     

Isolated posterior spinal artery aneurysm

Isolated aneurysms of the posterior spinal artery (not associated with arteriovenous malformations) are exceptionally rare. Three cases have been reported in the literature to date. We report a case of an isolated posterior spinal artery aneurysm causing acute subarachnoidal haemorrhage. Spinal artery aneurysms are contrasted with the more common intracranial aneurysms in terms of presentation and pathogenesis.     

Bilateral angiographic vasoconstriction of the middle cerebral and internal carotid arteries after subarachnoid haemorrhage in patients with and without aneurysms

Summary A retrospective study of cerebral angiographies from 173 patients with subarachnoid haemorrhage (SAH) were investigated and divided into three groups. The diameters of the middle cerebral artery and the internal carotid artery were measured and correlated with time elapsing between the onset of SAH and the angiographic study. A significant (p<0.001) reduction in vascular diameter was found at all levels of intraas well as extradural parts of the internal carotid artery in patients with aneurysms (group I). Also, bilateral angiographic investigation from 70 patients showed a significant (p<0.001) reduction at all levels on both sides, regardless of whether aneurysms were present (group II) or not (group III). Moreover, the reduction in vascular diameter was more pronounced in patients with than in patients without aneurysms. The most pronounced reduction in vascular diameter was found in one of the extradural parts of the internal carotid artery in both group II and III. However, reduction in vascular diamter did not correlate significantly with the cerebral circulation time despite a tendency towards it. On the other hand, layering of the contrast medium along the posterior wall of the internal carotid artery was more often found in patients with prolongation in cerebral circulation time suggesting a reduced cerebral blood flow in these patients. It is suggested that the significant reduction in vascular diameter of intra-as well as extradural parts of the internal carotid artery, might reflect an adaptation to altered cerebral metabolism after SAH.