Vaskuläre Erkrankungen des Kleinhirnbrückenwinkels

A connection between neurovascular conflicts within the cerebellopontine angle and vestibular neuritis, a case controlled cohort study

This retrospective, observer blinded case-control study aims to compare the prevalence of neurovascular conflicts (NVCs) of the vestibulocochlear nerve and the anterior inferior cerebellar artery (AICA) in patients presenting with clinical signs of acute vestibular neuritis with and without subsequent objective vestibular function loss (VFL). 58 acute cases of clinically suspected acute vestibular neuritis were investigated with same day cranial MRI at a tertiary referral centre and compared to 61 asymptomatic controls. The prevalence of NVCs in cases with objective VFL were also compared to cases without VFL. Radiologists described the NVC as "no contact" (Grade 0), "contact < 2 mm" (Grade 1), "contact > 2 mm" (Grade 2) and "vascular loop presence" (Grade 3) without knowledge of neurotological data. Neurotological data was collected without knowledge of MRI findings. Vestibular function was tested by bithermic caloric irrigation. 26 cases (45%) showed caloric VFL (Group A), whereas 32 (55%) exhibited no VFL (Group B). Group A included 13 cases with NVCs (50%), Group B included 26 NVC cases (82%) (p = 0.012) and the control group included 16 individuals (26%) (p < 0.001 for comparison of all 3 groups). Group B had a significantly higher NVC-Grading than Group A (p = 0.009). There was no statistically significant association between NVCs and either SNHL or tinnitus (p > 0.05). Our results suggest that patients presenting with clinical signs of acute vestibular neuritis who show symmetrical caloric vestibular function test results have a significantly higher NVC prevalence in the cerebellopontine angle.

Disabling vertigo and tinnitus caused by intrameatal compression of the anterior inferior cerebellar artery on the vestibulocochlear nerve: a case report, surgical considerations, and review of the literature

Microvascular compression of the vestibulocochlear nerve is known as a cause of tinnitus and vertigo in the literature, but our review of the literature shows that the compression is usually located in the cerebellopontine angle and not intrameatal.

We present a case of intrameatal compression of the anterior inferior cerebellar artery (AICA) on the vestibulocochlear nerve of a 40-year-old woman with symptoms of disabling vertigo and intermittent high-frequency tinnitus on the left side without any hearing loss for ∼ 4 years. Magnetic resonance imaging of the brain did not show any abnormality, but magnetic resonance angiography showed a left intrameatal AICA loop as a possible cause of the disabling symptoms. After the exclusion of other possible reasons for disabling vertigo, surgery was indicated. The intraoperative findings proved the radiologic findings. The large AICA loop was found extending into the internal auditory canal and compressing the vestibulocochlear nerve. The AICA loop was mobilized and separated from the vestibulocochlear nerve.

The patient's symptoms resolved immediately after surgery, and no symptoms were noted during 2 years of follow-up in our clinic. Her hearing was not affected by the surgery.

In addition to other common reasons, such as acoustic neuroma, disabling vertigo and tinnitus can occur from an intrameatal arterial loop compression of the vestibulocochlear nerve and may be treated successfully by drilling the internal acoustic meatus and separating the arterial conflict from the vestibulocochlear nerve.

Hemifacial spasm and reinnervation synkinesias: long-term treatment with either Botox or Dysport

Botulinum toxin is considered the treatment of choice for hemifacial spasm (HFS) and reinnervation synkinesias (RS). We present 133 patients with HFS (n = 97) and RS (n = 36) who have been treated with either Botox (n = 78) or Dysport (n = 55) exclusively for 6 years (range 2-12 years). The Botox dose was 21 +/- 8 MU, the Dysport dose 46 +/- 22 MU. The therapeutic effect started after 7.1 +/- 2.3 days and lasted for 12.5 +/- 3.9 weeks. It was stable throughout the observation period in 85% of all patients. Adverse effects occurred in 5.4% of injection series. No patient terminated treatment because of unsatisfactory results. Secondary therapy failure did not occur. With an effective conversion ratio of Botox:Dysport = 1:2.56 there were no differences between both drugs with respect to therapeutic efficacy and adverse effects thus confirming the hypothesis that there may not be intrinsic differences between both products.

Cerebellopontine angle meningioma presenting with hearing loss

We present the case of a 48-year-old woman with a cerebellopontine angle meningioma who presented with sensorineural hearing loss. The lesion was nearly 4 cm in maximum dimension and extended into the internal auditory canal. Hearing loss resulting from cerebellopontine angle tumor is most commonly caused by vestibular schwannomas, which arise directly from the sheath of the vestibular nerve (VIII) in the internal auditory canal. Our case provides a review of magnetic resonance imaging features that aid in differentiation of enhancing cerebellopontine angle masses that can have similar clinical presentations.

Hemifacial spasm caused by fusiform aneurysm at vertebral artery-posterior inferior cerebellar artery junction

Hemifacial spasm induced by intracranial aneurysm is a rare clinical condition. A 45-year-old male patient presented with a 3-year history of progressive involuntary twitching movement on right face. On radiological study, a dilated vascular lesion compressing the brain stem was found at the junction of vertebral artery and posterior inferior cerebellar artery. On operative field, we found the posterior inferior cerebellar artery and the fusiform aneurysm compressing root exit zone of facial nerve. Microvascular decompression was performed and the facial symptom was relieved without complications.

Multimodale MR-Diagnostik arteriovenöser Malformationen

Arteriovenous malformations (AVM) are complex inborn malformations of the vascular system. In the brain they can lead to severe complications, such as parenchymal haemorrhaging, epileptic seizures or neurologic failure, which necessitates a safe diagnosis and therapy. In addition to conventional angiography, magnetic resonance imaging (MRI) and MR angiography (MRA) have now been established as the gold standard diagnostic procedures. Using MRA the angioarchitecture of malformations can be captured and with a parallel imaging of the parenchyme the method is very well suited for therapy planning and monitoring. This review summarizes the present day possibilities of multimodal MRT diagnosis of AVM and describes the purely morphologic as well as the physiologic and pathophysiologic characteristics. The various MR angiographic techniques will be firstly described with respect to the basic technical principles and the results obtained so far will be summarized. The principle of functional MRT will be described and the diagnostic possibilities with respect to AVM will be discussed.

Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions in the cerebellopontine angle (CPA). However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Part 1 describes the different enhancing extra-axial CPA masses primarily arising from the cerebellopontine cistern and its contents, including vestibular and non-vestibular schwannomas, meningioma, metastasis, aneurysm, tuberculosis and other miscellaneous meningeal lesions.