Abnormal Rhomboid Lip and Choroid Plexus Should be Valued in Microvascular Decompression for Vestibulocochlear Diseases

BACKGROUND

Surgical outcomes for functional vestibulocochlear diseases vary, and the influencing factors are not fully understood. The role of a rhomboid lip (RL) and choroid plexus (CP) in microvascular decompression (MVD) of the vestibulocochlear nerve has not been studied. This study aims to evaluate the surgical efficacy of MVD for vestibulocochlear diseases, with and without addressing the RL and CP, to enhance our understanding of their etiology.

METHODS

A total of 15 patients who underwent MVD for the vestibulocochlear nerve between 2013 and 2022 were retrospectively identified and followed up. The patients were classified into 4 categories: vestibular paroxysmia (VP), benign positional paroxysmal vertigo (BPPV), and Meniere disease (MD). The fourth was a "tinnitus" group. The relief of symptoms, recurrence, satisfaction after surgery, available relevant imaging studies, and intraoperative observation data were evaluated.

RESULTS

Following MVD, 6 of the 7 patients in the VP group, the 1 patient in the BPPV group, and 1 of 2 patients in the MD group were completely relieved of vertigo. The seventh VP patient showed significant improvement. The 5 patients in the "tinnitus" group remained unchanged. Retrospectively, 4 patients from the VP, BPPV, and MD groups who underwent RL incision and CP excision were also free of vertigo, although vascular compression was not confirmed in these cases.

CONCLUSIONS

MVD is generally considered a useful treatment for VP and could also be effective in managing recurrent vertigo caused by BPPV and MD. Our results highlight the potential role of an abnormal RL and CP in the development of vertigo symptoms. Patients presenting with "tinnitus" require further investigation and might not be suitable for MVD.

Correlation of Preoperative High-Resolution Neurovascular Imaging and Surgical Success in Neurovascular Compression Syndromes

BACKGROUND

Neurovascular compression syndromes (NVCSs) are a group of neurological disorders characterized by compression of a cranial nerve and include trigeminal neuralgia (TN), hemifacial spasm, geniculate neuralgia, glossopharyngeal neuralgia, vestibular paroxysmia, and trochlear palsy. The European Academy of Neurology recommends constructive interference in steady-state/fast imaging employing steady-state (CISS/FIESTA) magnetic resonance imaging (MRI) in the evaluation of medically intractable TN, but similar recommendations do not exist for the remaining NVCSs.

METHODS

We conducted a retrospective chart review of 300 patients with an NVCS who underwent microvascular decompression (MVD) by a single neurosurgeon from 2004 to 2021. Data were collected on preoperative diagnosis, pre- and postoperative symptoms, presence/absence of preoperative high-spatial-resolution CISS/FIESTA MRI, and intraoperative findings. Rates of symptomatic improvement were used as a correlate of surgical success.

RESULTS

The rate of symptomatic improvement in the patients with a preoperative CISS/FIESTA MRI was 5.8% greater than those without preoperative high-spatial-resolution neuroimaging (98.8% vs. 93%, respectively; P = 0.008). Stratified by diagnosis, patients with TN had the greatest difference in surgical success between the 2 groups (99.3% vs. 92.9%, n = 268; P = 0.006). No statistically significant differences were observed in the other NVCSs, although positive trends were noted.

CONCLUSIONS

Preoperative CISS/FIESTA MRI correlated with greater rates of surgical success in cases of medically intractable TN; however, definitive conclusions could not be made regarding the remaining NVCSs. We support the recommendation that this imaging modality be included as part of the standard of practice for the evaluation and management of TN and encourage future studies to further elucidate this relationship for the less common NVCSs using a larger cohort.

Vestibular paroxysmia entails vestibular nerve function, microstructure and endolymphatic space changes linked to root-entry zone neurovascular compression

Combining magnetic resonance imaging (MRI) sequences that permit the determination of vestibular nerve angulation (NA = change of nerve caliber or direction), structural nerve integrity via diffusion tensor imaging (DTI), and exclusion of endolymphatic hydrops (ELH) via delayed gadolinium-enhanced MRI of the inner ear (iMRI) could increase the diagnostic accuracy in patients with vestibular paroxysmia (VP). Thirty-six participants were examined, 18 with VP (52.6 ± 18.1 years) and 18 age-matched with normal vestibulocochlear testing (NP 50.3 ± 16.5 years). This study investigated whether (i) NA, (ii) DTI changes, or (iii) ELH occur in VP, and (iv) to what extent said parameters relate. Methods included vestibulocochlear testing and MRI data analyses for neurovascular compression (NVC) and NA verification, DTI and ELS quantification. As a result, (i) NA increased NVC specificity. (ii) DTI structural integrity was reduced on the side affected by VP (p < 0.05). (iii) 61.1% VP showed mild ELH and higher asymmetry indices than NP (p > 0.05). (iv) "Disease duration" and "total number of attacks" correlated with the decreased structural integrity of the affected nerve in DTI (p < 0.001). NVC distance within the nerve's root-entry zone correlated with nerve function (Roh = 0.72, p < 0.001), nerve integrity loss (Roh = - 0.638, p < 0.001), and ELS volume (Roh = - 0.604, p < 0.001) in VP. In conclusion, this study is the first to link eighth cranial nerve function, microstructure, and ELS changes in VP to clinical features and increased vulnerability of NVC in the root-entry zone. Combined MRI with NVC or NA verification, DTI and ELS quantification increased the diagnostic accuracy at group-level but did not suffice to diagnose VP on a single-subject level due to individual variability and lack of diagnostic specificity.

Vestibular paroxysmia: clinical characteristics and long-term course

In 2016, the Bárány Society defined new diagnostic criteria for the neurovascular compression syndrome of the eighth nerve, called “vestibular paroxysmia” (VP), differentiating between definite (dVP) and probable (pVP) forms. The aim of this study was (1) to describe clinical symptoms and laboratory findings in a well-diagnosed large patient cohort according to those criteria, and (2) to evaluate the long-term course over years in dVP. We identified 146 patients (73 dVP, 73 pVP) from our tertiary dizziness center registry. Data of structured history-taking, clinical neurological, neuro-ophthalmological/-otological examinations as well as MRI imaging were extracted for analyses. Overall, attack frequency ranged between 5 and 30 attacks per day; spinning vertigo was the most frequent type. In two-thirds of patients, attacks occurred spontaneously; in one-quarter, they were triggered by head movements. The majority (approximately 70%) reported no accompanying symptoms; in those with symptoms, mild unilateral cochlear symptoms prevailed. One-third of patients initially showed hyperventilation-induced nystagmus without specific direction, and a deviation of the subjective visual vertical between 3° and 6°. Complete loss of peripheral vestibular function was never evident. dVP and pVP significantly differed concerning the vertigo type, e.g., spinning vertigo was more frequent in dVP. Fortunately, three-quarters of dVP patients remained attack-free during follow-up (mean 4.8 years, standardized questionnaire), more than half of them even without any medication. Patients with ongoing attacks showed significantly higher attack frequency at baseline, but reported persistent frequency reduction. Overall, the long-term prognosis of VP appears favorable, not necessarily requiring ongoing treatment.

Application of ABR in pathogenic neurovascular compression of the 8th cranial nerve in vestibular paroxysmia

PURPOSE

To investigate the clinical value of electrophysiological tests in indicating pathogenic vascular contact of the 8th nerve in definite vestibular paroxysmia (VP) cases to provide a reference for decompression surgery.

METHODS

We retrospectively analyzed patients who had vertigo, unilateral tinnitus, or hearing loss and exhibited vascular contact of the 8th cranial nerve by MRI. Participants were classified into the VP or non-VP group according to the criteria of the Bárány Society in 2016. The demographic characteristics and audiological and electrophysiological test results of the two groups were compared. Receiver operating characteristic (ROC) curves were calculated for ABR to determine the best parameters and cutoff values to predict the existence of pathological neurovascular contact in VP.

RESULTS

Thirteen patients in the VP group and 66 patients in the non-VP group were included. VP patients had longer interpeak latency (IPL) I-III and wave III latency compared to non-VP patients (p < 0.001; p < 0.001). According to the ROC analyses, IPL I-III and wave III latency were the best indicators for the diagnosis of VP. The optimal cutoff for IPL I-III was 2.3 ms (sensitivity 84.6%, specificity 95.5%), and that for wave III latency was 4.0 ms (sensitivity 92.3%, specificity 77.3%). There were no differences in the PTA, caloric test, o-VEMP, or c-VEMP results between the two groups.

CONCLUSION

Prolonged IPL I-III and the wave III latency of ABR strongly suggested that vascular contact of the 8th cranial nerve was pathological, which may provide some references for microvascular decompression surgery of VP.

Vestibular paroxysmia: Clinical features and imaging findings; a literature review

According to the definition of neurovascular compression syndromes (NVCS), a vascular structure in direct contact with a cranial nerve is causing mechanical irritation of the neural tissue producing correlating symptoms. Vestibular paroxysmia is an example of a neurovascular compression which is caused by neurovascular contact between the eighth cranial nerve and a vessel. It is crucial to understand the unique anatomy of the vestibulocochlear nerve in order to study the syndrome which is the result of its compression. More specifically, the long transitional zone between central and peripheral myelin plays a central role in clinical significance, as the transitional zone is the structure most prone to mechanical injury. Imaging techniques of the eighth cranial nerve and the surrounding structures are substantial for the demonstration of clinically significant cases and potential surgical decompression. The goal of the current review is to present and study the existing literature on vestibular paroxysmia and to search for the most appropriate imaging technique for the syndrome. An extensive literature search of PubMed database was performed, and the studies were ranked based on evidence-based criteria, followed by descriptive statistics of the data. The present analysis indicates that 3D CISS MRI sequence is superior to any other sequence, in the most studies reviewed, regarding the imaging of neurovascular compression of the eighth cranial nerve.

Cardiogenic vertigo: characteristics and proposed diagnostic criteria

Early identification of cardiogenic vertigo (CV) is necessary to prevent serious complications of cardiovascular diseases. However, the literature is limited to case reports without detailed clinical features or diagnostic criteria. The aim of this study was to define characteristics of CV and propose diagnostic criteria. This study included patients with CV diagnosed at Pusan National University and Keimyung University Hospitals. Demographic, clinical, laboratory, and treatment data were analyzed. Of 72 patients with clinically suspicious CV, 27 were finally included. The age ranged from 63 to 88 years (75.1 ± 7.2 years). Recurrent vertigo occurred without syncopal attacks in 52% [95% CI, 32-71], while it preceded (37% [19-58]) or followed (11% [2-29]) syncope. The patients with recurrent isolated vertigo had suffered from symptoms from 15 days to 5 years until final diagnosis (median 122 days). The vertigo lasted only for a few seconds (93% [76-99]) or a few minutes (7% [1-24]). Fourteen patients presented with spinning vertigo, and one of them showed spontaneous downbeat nystagmus during the attack. Accompanying symptoms including chest discomfort, palpitation, headache, arm twitching, and lightheadedness were found in 70% [50-86]. Between patients with and without syncope, there was no difference in clinical parameters and results of cardiac function tests. The most common cardiac abnormality during the attacks of vertigo was bradyarrhythmia (89% [71-98]). Cardiovascular diseases can develop recurrent isolated vertigo without or preceding syncope. Onset age, duration of vertigo, accompanying symptoms, and underlying cardiac diseases can aid in differentiation from other vestibular disorders. Early identification of CV would reduce morbidity and mortality associated with cardiac syncope.

Unilateral cochleovestibular nerve compression syndrome in a patient with bilateral IAC osteoma

INTRODUCTION

Osteomas of the internal auditory canal are rarely reported in the literature. Patients may complain of disabling symptoms of dizziness, hearing loss, and vestibular dysfunction. We report the case of a patient with bilateral osteomas of the internal auditory canal (IAC) associated with bilateral neurovascular compression mainly affecting the right cochleovestibular nerve (VIII) and right anterior inferior cerebellar artery (AICA).

OBSERVATION

This 75-year-old woman patient complained of disabling paroxysmal vertigo, typewriter tinnitus and hearing loss of the right ear. Temporal bone computed tomography showed bilateral osteoma arising from the posterior superior wall of the IAC. MRI sequences of the right VIII demonstrated compression by the right AICA against the inferior wall of the narrowed IAC. Treatment with oxcarbazepine allowed marked and lasting improvement of the patient's symptoms.

CONCLUSION

To our knowledge, this is the first description of an ipsilateral neurovascular compression syndrome of the VIII secondary to the presence of an osteoma narrowing the IAC.

Vestibular paroxysmia in vestibular neuritis: A case report

The term vestibular paroxysmia (VP) was introduced for the first time by Brandt and Dieterich in 1994. In 2016, the Barany Society formulated the International Classification of VP, focusing in particular on the number and duration of attacks, on the differential diagnosis and on the therapy. Ephaptic discharges in the proximal part of the eighth cranial nerve, which is covered by oligodendrocytes, are assumed to be the neural basis of VP. We report the first case in literature of an onset of symptoms and signs typical of VP in a young man following acute unilateral vestibular loss not combined with auditory symptoms. Indeed, the pathogenic mechanism affected only the vestibular nerve as confirmed by the presence of a stereotyped nystagmus pattern. The magnetic resonance imaging didn’t reveal any specific cause therefore we suggest the possible role of a neuritis triggering an ephaptic discharge as the neural mechanism of VP.

A randomized double-blind, placebo-controlled, cross-over trial (Vestparoxy) of the treatment of vestibular paroxysmia with oxcarbazepine

Objective

Vestibular paroxysmia (VP) is characterized by short, often oligosymptomatic attacks of vertigo which occur spontaneously or are sometimes provoked by turning the head. Despite the description of the disease almost 40 years ago (first termed “disabling positional vertigo”), no controlled treatment trial has been published to date. The Vestparoxy trial was designed as a randomized, placebo-controlled, double-blind cross-over trial to examine the therapeutic effect of oxcarbazepine (OXA) in patients with definite or probable VP.

Methods

Patients were recruited from August 2005 to December 2011 in the outpatient Dizziness Unit of the Department of Neurology of the Munich University Hospital, and randomized to receive OXA (first week: 300 mg once per day, second week: 300 mg b.i.d., third week: 300 mg t.i.d. until the end of the third month), followed by placebo or vice versa with a 1-month wash-out period in between. The primary endpoint was the number of days with one or more attacks. Secondary endpoints were the number of attacks during the observed days, and the median (for each day) duration of attacks. All these endpoints were assessed using standardized diaries collected at the end of each treatment phase.

Results

Forty-three patients were randomized, 18 patients provided usable data (2525 patient days) for at least one treatment phase and were included in the main (intention-to-treat) analysis. The most common reasons for discontinuation documented were adverse events. The risk of experiencing a day with at least one attack was 0.41 under OXA, and 0.62 under placebo treatment, yielding a relative risk of 0.67 (95% CI 0.47–0.95, p = 0.025). The number of attacks during the observed days ratio was 0.53 (95% CI 0.42–0.68, p < 0.001) under OXA compared to placebo. Median attack duration was 4 s (Q25: 2 s, Q75: 120 s) under OXA, and 3 s (Q25: 2 s, Q75: 60 s) under placebo treatment. When days with no attacks, i.e., duration = 0, were included in the analysis, these figures changed to 0 (Q25: 0, Q75: 3 s), and 2 (Q25: 0, Q75: 6 s). No serious adverse events or new safety findings were identified during the trial.

Conclusions

The Vestparoxy trial showed a significant reduction of VP attacks under OXA compared to placebo treatment, confirming the known and revealing no new side effects.

carbamazepine with betahistine mesilate tablets in treating vestibular paroxysmia: a retrospective review

OBJECTIVES

Vestibular paroxysmia (VP) is a rare episodic peripheral vestibular disorder that can cause acute short attacks of vertigo. This study aimed to compare the efficacy and acceptability of carbamazepine (CBZ), CBZ plus betahistine mesilate tablets (BMT) and oxcarbazepine (OXC) plus BMT in treating VP within 12 weeks.

METHODS

A retrospective analysis of data from 196 VP patients treated in our hospital was conducted. There were 73 patients receiving CBZ, 65 patients receiving CBZ+BMT and 58 patients receiving OXC+BMT. The frequency of vertigo, vertigo duration, vertigo score, response rate (RR) and side effects were compared between groups to assess efficacy and acceptability at the end of 12(th) week.

RESULTS

After 12 weeks' treatment, the CBZ+BMT group had a greater reduction in the frequency of vertigo, vertigo duration and vertigo score than the other two groups. The RR was highest in the CBZ+BMT group, second in the OXC+BMT group and lowest in the CBZ group. The incidence of side-effects was highest in the CBZ group, second in the CBZ+BMT group and lowest in the OXC+BMT group. Two patients in the CBZ group were withdrawn.

CONCLUSION

These results indicated that using BMT as an augmentation for CBZ or OXC might be a good choice in treating VP.

Vestibular paroxysmia: a treatable neurovascular cross-compression syndrome

The leading symptoms of vestibular paroxysmia (VP) are recurrent, spontaneous, short attacks of spinning or non-spinning vertigo that generally last less than one minute and occur in a series of up to 30 or more per day. VP may manifest when arteries in the cerebellar pontine angle cause a segmental, pressure-induced dysfunction of the eighth nerve. The symptoms are usually triggered by direct pulsatile compression with ephaptic discharges, less often by conduction blocks. MR imaging reveals the neurovascular compression of the eighth nerve (3D constructive interference in steady state and 3D time-of-flight sequences) in more than 95 % of cases. A loop of the anterior inferior cerebellar artery seems to be most often involved, less so the posterior inferior cerebellar artery, the vertebral artery, or a vein. The frequent attacks of vertigo respond to carbamazepine or oxcarbazepine, even in low dosages (200–600 mg/d or 300–900 mg/d, respectively), which have been shown to also be effective in children. Alternative drugs to try are lamotrigine, phenytoin, gabapentin, topiramate or baclofen or other non-antiepileptic drugs used in trigeminal neuralgia. The results of ongoing randomized placebo-controlled treatment studies, however, are not yet available. Surgical microvascular decompression of the eighth nerve is the “ultima ratio” for medically intractable cases or in exceptional cases of non-vascular compression of the eighth nerve by a tumor or cyst. The International Barany Society for Neuro-Otology is currently working on a consensus document on the clinical criteria for establishing a diagnosis of VP as a clinical entity.

[Peripheral, central and functional vertigo syndromes]

Depending on the temporal course, three forms of vertigo syndrome can be differentiated: 1) vertigo attacks, e.g. benign paroxysmal positional vertigo (BPPV), Menière's disease and vestibular migraine, 2) acute spontaneous vertigo lasting for days, e.g. acute unilateral vestibulopathy, brainstem or cerebellar infarction and 3) symptoms lasting for months or years, e.g. bilateral vestibulopathy and functional vertigo. The specific therapy of the various syndromes is based on three principles: 1) physical treatment with liberatory maneuvers for BPPV and balance training for vestibular deficits, 2) pharmacotherapy, e.g. for acute unilateral vestibulopathy (corticosteroids) and Menière's disease (transtympanic administration of gentamicin or steroids and high-dose betahistine therapy); placebo-controlled pharmacotherapy studies are currently being carried out for acute unilateral vestibulopathy, vestibular paroxysmia, prophylaxis of BPPV, vestibular migraine, episodic ataxia type 2 and cerebellar ataxia; 3) psychotherapy for functional dizziness.