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At least 19 recordsLinked to original sources
PubMed1995

Management of posterior cranial fossa meningiomas.

Posterior cranial fossa meningiomas are relatively common extra-axial tumors with important relationships to the cochleovestibular system, facial nerve, and/or cranial base. Nevertheless, objective reporting of auditory and vestibular function is rare for this patient population, and a full discussion of the nonsurgical management is all but totally discounted in the otolaryngology literature. Nine cases (8 operative cases) are presented, with the purpose of correlating neurotologic function with precise anatomic tumor location, available by magnetic resonance imaging and computed tomography. The usefulness of this information for diagnosis and meaningful scrutiny of the operative results is discussed. A comprehensive review of posterior fossa meningiomas in terms of epidemiology, etiology, and pathology, as well as nonsurgical treatment alternatives, is provided.

Adolescent↗
PubMedDate not supplied

[Diagnostic problems in epidural hematoma of the posterior cranial fossa].

Posttraumatic posterior cranial fossa haematoma is a rare occurrence. In our material it accounted for 1.5% of all intracranial haematomas. Due to its infrequency and diagnostic difficulties these patients are referred with delay to neurosurgeons and often die with signs of brain stem lesion. The reported case was a 25-year-old man with this haematoma and considerable diagnostic difficulties were encountered despite the application of modern imaging techniques. These difficulties hamper the qualification of the patient for operation which is the method of choice in these cases.

Adult↗
PubMed1977

Vessel tortuosity as a cause of posterior fossa cranial nerve syndromes.

Neurologic syndromes may be caused by mechanical vascular compression of cranial nerves in the posterior fossa. The clinical expression is variable and can be divided into two main groups. Isolated cranial nerve involvement is most frequently associated with tortuous, elongated vertebral and basilar arteries as well as redundant loops of the anteroinferior cerebellar artery. Pseudotumoral manifestations of cranial nerve involvement at the level of the cerebellopontine angle are more frequently related to aneurysms of the vertebral and basilar arteries.

Adult↗
PubMed1987

Topography of vestibulocochlear nerve fibers in the posterior cranial fossa.

In the posterior cranial fossa, the separation of the vestibular and cochlear subdivisions of the eighth nerve is clear in about 75% of cases. Although in the remaining cases the vestibulocochlear cleavage plane is not visible macroscopically, the large-fibered vestibular subdivision and the small-fibered cochlear subdivision are well recognized in histological sections. Within the cochlear subdivision, some fibers of large caliber are mixed with fibers of small caliber in a region we named the "overlapping zone." We studied, histologically, cross sections of the intracranial portion of six eighth nerves at about 5 mm proximal to the porus acusticus. A computerized video system was used to measure the diameters of the fibers of the vestibular and cochlear subdivisions localized at different distances from the vestibulocochlear cleavage plane. The overlapping zone is located within the cochlear subdivision adjacent to the vestibulocochlear cleavage plane. It has a pear-like shape, with the larger part occupying the anterosuperior part of the cochlear subdivision. The mean cross-sectional area of this zone in our six samples is about 0.4 mm2, which is approximately 23% of the area of the cochlear subdivision. The thickness of the zone in the superior-inferior direction ranges from 0.23 mm to 0.55 mm. The parameters of the described overlapping zone should be taken into consideration in vestibular neurectomy, in which complete sectioning of the vestibular fibers is important.

Adult↗
PubMedDate not supplied

[Teratoma of the posterior cranial fossa].

Two cases of posterior cranial fossa teratomas are reported. The rarity of these lesions is stressed. In the material of surgically treated cases of brain tumours from a period of 12 years in only two patients teratomas of this location were found. In adults they are extremely rare. In both cases teratoma finding during the operation was a surprise for the neurosurgeons and this was confirmed by literature reports.

Adult↗
PubMed1997

Pathogenesis of Chiari malformation: a morphometric study of the posterior cranial fossa.

To investigate overcrowding in the posterior cranial fossa as the pathogenesis of adult-type Chiari malformation, the authors studied the morphology of the brainstem and cerebellum within the posterior cranial fossa (neural structures consisting of the midbrain, pons, cerebellum, and medulla oblongata) as well as the base of the skull while taking into consideration their embryological development. Thirty patients with Chiari malformation and 50 normal control subjects were prospectively studied using neuroimaging. To estimate overcrowding, the authors used a "volume ratio" in which volume of the posterior fossa brain (consisting of the midbrain, pons, cerebellum, and medulla oblongata within the posterior cranial fossa) was placed in a ratio with the volume of the posterior fossa cranium encircled by bony and tentorial structures. Compared to the control group, in the Chiari group there was a significantly larger volume ratio, the two occipital enchondral parts (the exocciput and supraocciput) were significantly smaller, and the tentorium was pronouncedly steeper. There was no significant difference in the posterior fossa brain volume or in the axial lengths of the hindbrain (the brainstem and cerebellum). In six patients with basilar invagination the medulla oblongata was herniated, all three occipital enchondral parts (the basiocciput, exocciput, and supraocciput) were significantly smaller than in the control group, and the volume ratio was significantly larger than that in the Chiari group without basilar invagination. These results suggest that in adult-type Chiari malformation an underdeveloped occipital bone, possibly due to underdevelopment of the occipital somite originating from the paraxial mesoderm, induces overcrowding in the posterior cranial fossa, which contains the normally developed hindbrain. Basilar invagination is associated with a more severe downward herniation of the hindbrain due to the more severely underdeveloped occipital enchondrium, which further exacerbates overcrowding of the posterior cranial fossa.

Adolescent↗
PubMed1991

Retrosigmoidal approach to the posterior cranial fossa. An anatomical study.

An anatomical study was performed in order to obtain help for orientation regarding the retrosigmoid approach and its osteoclastic craniotomy. The insertions of the sternocleidomastoid, the splenius capitis, the longissimus capitis and the obliquus capitis superior muscles were measured. The relationships of the insertions to different landmarks were also ascertained (FHP, suprameatal spine). In 37 specimens 6 burrholes with a standardized relationship to the Frankfurt Horizontal Plane (FHP) and the external auditory meatus, were performed. Due to the results of the relationship between burrholes and the sigmoid and transverse sinuses it is possible to give an optimal position for the initial burrhole of the osteoclastic craniotomy. A burrhole performed according to the result of this study has a relatively small risk concerning iatrogenic bleeding from the sigmoid and transverse sinuses caused by the burrhead of the drill.

Cephalometry↗
PubMed1999

[Monitoring of the auditory stem evoked potentials in removal of tumors of the posterior cranial fossa].

The material of intraoperative monitoring of the acoustic stem evoked potentials (ASEP) in 9 patients with tumors of the stem and in 28 patients with the parastem localization was analyzed. It was shown that changes in the amplitude of ASEP rather than latency were the decisive factor in the assessment of the functional state of the brain stem. It was found that even the pronounced changes of the bioelectrical activity recorded during the excision of the tumor could be reversible after a change of the strategy of the operative intervention and/or after performing the necessary therapeutic measures. An important test of favorable prognosis of the postoperative course is considered to be the normalization of brain activity, ASEP included, at the final stages of the operation.

Adolescent↗
PubMedDate not supplied

[Arteriosinus anastomoses of the posterior cranial fossa (pathologic anatomy)].

Postmortem examination of the brain of 10 patients with occipito-sinus anastomoses showed that the morphological basis of this vascular pathology is an anatomical developmental defect of vessels of the system of the external and internal carotid arteries and dura mater sinuses with disturbed histological structure of their walls. Severe abnormality of calcium metabolism of the type of systemic calciphilaxis with involvement of the brain and viscera is encountered simultaneously in some cases. The combination of these pathological processes leads finally to gradually increasing circulatory disorders, brain hypoxia, and severe damage to the brain matter.

Adolescent↗