Successful removal of an intrapontine haematoma

Role of superselective angiography in the detection and endovascular treatment of ruptured occult arteriovenous malformations

SUMMARY

Three cases of occult micro-arteriovenous malformations not identified by cerebral angiography or other imaging modalities were detected by superselective angiography. The first case had a small intracerebral hemorrhage in the superior colliculus, the second had a perimesencephalic subarachnoid hemorrhage, and the third presented with intracerebral hemorrhage combined with massive intraventricular hematoma. While repeated selective cerebral angiography (four-vessel study) was negative, superselective angiography clearly demonstrated each lesion with small early venous filling in accordance with the location of hematoma. Successful superselective embolization with polyvinyl alcohol particles was performed in each micro-arteriovenous malformation by flow-guided microcatheter without postoperative complications. Our experience suggests that superselective angiography is necessary to visualize micro-arteriovenous malformations in patients with cerebral hemorrhage and negative four-vessel angiography. Furthermore, the superselective endovascular approach has the advantage of offering immediate obliteration of the micro-shunt, thereby reducing or eliminating the risk of further hemorrhage.

The anatomical aspects of a surgical approach through the floor of the fourth ventricle

In 1993 Kyoshima et al. introduced safe entry zones in the region of the 4th ventricle floor: infrafacial triangle and suprafacial triangle. Is it possible to demarcate these zones precisely in every case intra-operatively? A postmortem study of 40 brainstems of patients who had died of non-brain disease was performed to evaluate the degree of individual morphological and morphometrical variability of the 4th ventricle floor. The purpose of this study was to find constant landmarks and distances within the rhomboid fossa region which would help a neurosurgeon to determine safe approach zones through the 4th ventricle floor to brainstem lesions. Several anatomical landmarks-median sulcus, obex, vestibular area, vagal triangle, hypoglossal triangle-were found to be sufficiently visible in all examined brainstems. However, the facial colliculus which is a border structure between the infrafacial and suprafacial safe approach zone was poorly visible in about 37% of the analyzed material. The striae medullares were not found to be good orientation structures as they were not visible in 30% of the material and exhibited individual variability of a high degree in relation to their number and arrangement. In the morphometrical study analyzed measurements were taken by utilizing the digital image analyzer MULTISCAN. Based on the results obtained the authors suggest new borders of the infrafacial safe approach zone and morphometrical directions to determine the suprafacial safe approach zone in cases when the facial colliculus is not clearly visible or invisible intra-operatively.

Surgical management of hematomas of the brain stem

Nine patients with brain-stem hematoma were admitted to the authors' institute during the period from 1985 to 1988. Clinical symptoms and signs pointed to pontine involvement in most cases. Progressive clinical deterioration was quite common and usually led to a clinical diagnosis of brain-stem intra-axial tumor. Angiography was noncontributory; computerized tomography (CT) was the main diagnostic test. This gave evidence of different pathological characteristics, including masses showing highly increased density, nonhomogeneous hyperdense lesions, and isodense lesions with peripheral contrast enhancement. No clear correlation was found, however, between the presumed duration of the clinical picture and the CT characteristics of the lesion. In the last four cases, magnetic resonance imaging was performed using a 0.015-tesla resistive system. This examination usually confirmed the presence of a brain-stem mass already shown by previous CT scans. There were, however, no cases in which direct evidence of an intra-axial vascular malformation could be obtained. The patients were all treated surgically with an attempt at total removal of the lesion and thorough inspection of the hematoma cavity and biopsy. Evidence of "cryptic" arteriovenous malformation was obtained in six of the nine cases. There were minor transitory complications in three cases. All of the patients were able to resume their previous activity, and none suffered recurrence of the symptoms following the operation. It may be concluded that surgery is the treatment of choice for brain-stem hematoma.

Surgical management of brain stem vascular malformations

Vascular malformations of the brain stem are a histologically heterogenous collection of lesions which most often present with sudden and progressive neurologic deficit related to haemorrhage. Since 1987 the authors have treated eleven cases of brain stem vascular malformation. Seven of the patients were treated with complete surgical extirpation of the haematoma and malformation because of progressive neurologic deficit. Four additional patients made a full neurologic recovery and are being carefully observed for signs suggestive of the need for surgical treatment. Complete surgical excision of brain stem vascular malformations is mandatory for patients with progressive neurologic deficit related to recurrent haemorrhage.

Mesencephalic haematoma, successful surgical evacuation. Case report

A case of mesencephalic haematoma is reported. Emergency surgical evacuation of haematoma was done. The patient improved and has done well for five years. Subtemporal and infratentorial supracerebellar approaches have been used earlier to remove mesencephalic haematoma. It is possible to remove caudal midbrain haematoma via a IVth ventricular approach causing minimal damage.

Diagnosis and treatment of vascular brain-stem malformations

Vascular malformations are a common cause of spontaneous brain-stem hemorrhage in young normotensive individuals. These lesions are no longer cryptic. Magnetic resonance (MR) imaging has renewed interest in the treatment of this disorder because of the precise accuracy in diagnosis and localization of these lesions that it affords. The MR image demonstrates characteristic findings of multiple hemorrhages of varying ages surrounded by a hypointense peripheral zone of hemosiderin. Five cases of vascular brain-stem malformation diagnosed with MR imaging are described. The vascular malformations could be demonstrated as "flow void" areas in three cases. Three patients were treated surgically and vascular malformations were confirmed: all three patients improved postoperatively. Two patients were treated nonsurgically; one of these recovered from a second hemorrhage and the other experienced neurological deterioration after a single hemorrhage. High-energy radiotherapy was not effective for the one vascular malformation treated by this method. This experience suggests that surgical exploration should be considered for vascular brain-stem malformations when the diagnosis is confirmed by MR criteria and the clinical course and lesion are both progressive in character.

[Primary hematoma of the brain stem: considerations apropos of a case]

The case of a 48 year-old woman presenting with a primary pontine hematoma is reported. The clinical evolution simulated a brain stem tumor and the diagnosis of hematoma was not established before the operation. The preoperative neurological deficit improved except for a facial nerve palsy. These hematomas are thought to be due to rupture of "cryptic" arteriovenous malformations and should be differentiated from those secondary to systemic hypertension. The diagnosis of brain stem hematomas should be considered in any case of brain stem lesion, especially in young and normotensive patients.

Brainstem haematomas: review of the literature and presentation of five new cases

Fifty-one cases of brainstem haematoma that have undergone neurosurgical intervention since Finkelnburg's first exploration in 1905, are presented, together with five new cases. The location, incidence, aetiological and pathological factors, as well as clinical syndromes are reviewed. Diagnostic criteria are presented. The distinction between brainstem "haematoma" and "haemorrhage" is stressed. A retrospective comparison of 56 surgically treated cases and 31 conservatively managed cases is made, as is an analysis of the natural history of the disease process. Based on currently available data, the conclusion is drawn that patients with brainstem haematomas fare quite well after surgical therapy.

Brain stem expansive lesions: stereotactic biopsy for a better therapeutic approach

CT diagnosed brain stem malignant lesions were in the past almost always treated with radiation therapy (RT). Eventually this turned out to be a grave mistake. With stereotactic serial biopsies of all brain stem expanding lesions we have been able to verify the histological nature in all cases but two and to prevent a blind therapeutic approach. In 24 patients bearing CT diagnosed expansive lesions into the brain stem 68 samples were taken during 24 stereotactic procedures. In 8 patients surgical removal of the expanding lesion was attempted after stereotactic biopsy.

Acute direct and indirect lesions of the brain stem--CT findings and their clinical evaluation

Since the introduction of computer tomography (CT) (Ambrose 1973, Hounsfield 1973) it has become an essential instrument in the diagnosis of acute intracranial lesions. The precise analysis of the CT and in particular the evaluation of the basal cisterns, yields results which are already wellknown, basically, from post-mortem investigations and clinical findings. However, while these were retrospective analyses and results, serial CT examinations which are free of risk for the patient and can be used in correlation with the clinical neurological findings, allow important assertions intra vitam, as well as a definitely better assessment of the prognosis. In addition to acute supratentorial lesions, acute and subacute infratentorial lesions are analysed and their clinical significance described. In this way, for the first time, the dynamics of the mechanical factors in raised intracranial pressure can be analysed. Important conclusions are drawn for the clinical management of the patients, and even some new indications for operation. Analysis of the acute hyperdense brain stem lesions--pathognomonic for haemorrhages--allows for the first time the diagnosis and continuous observation of traumatic and secondary haemorrhages caused by raised pressure, as well as spontaneous ones. As regards the mortality and morbidity, the results in this large series of traumatic and secondary haemorrhages are in striking contrast to previous analyses based on post mortem findings. Acute hypodense brain stem lesions are not amenable to any definite pathogenetic classification--softening, inflammatory lesions, tumours and oedema must all be considered. With acute lesions we are only dealing with infarcts, which are only incompletely assessable in the computer tomogram, and their diagnosis must still depend on the clinical findings. Secondary ischaemic lesions in acute raised intracranial pressure are identifiable in over 18% as infarcts which involve the entire territory of an artery. These additional space-occupying lesions are only survived by 11% of the patients. Hence the correlation which has been established between the basal cisterns and intracranial pressure is of great clinical significance. From our own research group several reports on different aspects of raised intracranial pressure and lesions of the brain stem have appeared since 1979. Similar analyses of partial aspects of the basal cisterns, have been published only recently, and came essentially to the same conclusions.

Brainstem haematoma due to presumed cryptic telangiectasia

Three patients with primary brainstem haematoma are reported. The clinical presentation suggested an initial diagnosis of pontine tumour in two and demyelination in one patient. The subacute course is characteristic of brainstem haematoma due to presumed cryptic telangiectasia, the abnormal vessels being destroyed by the haemorrhage. These findings emphasise the importance of considering haematoma due to cryptic telangiectasia in the differential diagnosis of subacute brainstem lesions.

Surgical treatment of cryptic AVM's and associated hematoma in the brain stem and spinal cord

Most surgically treated cases of brain-stem hematomas have been attributed to rupture of cryptic arteriovenous malformations (AVM's); however, very few cases have been histologically proven. Similarly, there are very few reports of surgically treated spontaneous hematomyelia, in which the hemorrhage has been histologically confirmed as being due to a purely intramedullary AVM. The authors report three cases with surgically treated, histologically confirmed AVM's, of which two were in the brain stem and the third was in the spinal cord. In all these cases, abnormal vascular tissue in the wall of the hematoma cavity was recognized at operation and excised.

Successful treatment of a basilar aneurysm presenting as a brainstem hemorrhage

A case of large brainstem hemorrhage resulting from a basilar artery aneurysm is reported. This extremely rare disorder is fatal in a large majority of cases, and has usually been reported after autopsy. This case presents a successful recovery after clipping the aneurysm.

Successful removal of pontine haematoma due to rupture of cryptic arteriovenous malformation. Case report

One case of a pontine haematoma with clinical symptoms of cerebellopontine angle tumour is described. The haematoma was successfully evacuated, and preoperative neurological deficits disappeared except for minimal right fifth nerve palsy. The pathological specimen was diagnosed as arteriovenous malformation. Lateropontine haematomas must be included in the differential diagnosis of cerebellopontine angle tumours.

A report of six surgically treated cases

Six cases of brain-stem hematoma are described. The clinical presentation in these cases was extremely variable. Operative evacuation of the hematoma resulted in immediate improvement in all cases, and a full or nearly full recovery in five. Untreated brain-stem hematoma is probably always fatal, whereas surgical evacuation is effective and safe. The diagnosis of brain-stem hematoma should be considered in any case of brain-stem lesion.

Pontine hematomas

Pontine hematomas are very rare lesions that in the past were found at postmortem examination rather than diagnosed from the clinical presentation. The advent of computed tomography allowed more frequent identification of those lesions which has shown a more favorable prognosis than formerly thought. Three patients suffering from intrapontine hematomas, revealed by computed tomography, are discussed. The etiopathogenesis, location, and clinical features of this lesion are discussed in an attempt to establish general criteria from adequate management. All 3 patients (2 treated conservatively and 1 by surgical evacuation) had a successful outcome. Repeat CT scans gave evidence of resolution of this lesion in all patients.

Primary brain stem haematomas. Diagnosis and treatment

Case histories are reported of 18 patients in whom the diagnosis of primary brain stem haematoma and brain stem haemorrhage was made by computed tomography (CT). The possibility of an early diagnosis of brain stem haematoma, and the differential diagnosis of brain stem haemorrhage by a combination of clinical and tomodensitometric criteria is emphasized. It is concluded that CT is a highly reliable method for the diagnosis, location, and management of brain stem haematoma.