Pre-habilitation with intratympanic gentamicin in vestibular schwannomas: a systematic review.

OBJECTIVE: To assess whether pre-habilitation with intratympanic gentamicin can accelerate vestibular compensation following vestibular schwannoma resection. METHODS: Seventeen studies were retrieved from the databases Medline, PubMed, Frontiers, Cochrane Library, Cambridge Core and ScienceDirect. Eight of the 17 studies met our criteria; the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. Heterogeneity, risk of bias and effect on post-operative recovery were assessed. RESULTS: Four of the eight studies showed a statistically positive effect of pre-habilitation with gentamicin on the post-operative recovery process; the remainder also reported benefits, although not statistically significant. No study reported negative effects. Limitations were linked mostly to the limited number of enrolled patients and the outcome assessment methods. CONCLUSION: Fifty per cent of the studies found a statistically positive effect of pre-habilitation with gentamicin prior to vestibular schwannoma resection. While the results are promising, due to the limited numbers further prospective studies are required to strengthen the evidence.

How many growing vestibular schwannomas tend to stop growing without any treatment?

OBJECTIVE: To determine the long-term, spontaneous growth arrest rates in a large cohort of vestibular schwannoma patients. METHODS: This paper describes a retrospective case series of 735 vestibular schwannoma patients organised into four groups: group A patients showed tumour growth which then stopped without any treatment; group B patients showed tumour growth which continued, but were managed conservatively; group C patients had a growing vestibular schwannoma and received active treatment; and group D patients had a stable, non-growing vestibular schwannoma. Demographics, tumour size and vestibular schwannoma growth rate (mm/month) were recorded. RESULTS: A total of 288 patients (39.2 per cent) had growing vestibular schwannomas. Of the patients, 103 (35.8 per cent) were managed conservatively, with 52 patients (50.5 per cent of the conservative management group, 18 per cent of the total growing vestibular schwannoma group) showing growth arrest, which occurred on average at four years following the diagnosis. Eighty-two per cent of vestibular schwannomas stopped growing within five years. Only differences between age (p = 0.016) and vestibular schwannoma size (p = 0.0008) were significant. CONCLUSION: Approximately 20 per cent of growing vestibular schwannomas spontaneously stop growing, predominantly within the first five years; this is important for long-term management.

A systematic review on delayed acquisition of post-gadolinium magnetic resonance imaging in Ménière's disease: imaging of the endolymphatic spaces.

OBJECTIVE: This study aimed to assess the clinical implications of delayed-acquisition post-gadolinium magnetic resonance imaging in identifying endolymphatic hydrops in Ménière's disease. METHOD: This study was a systematic review using Medline and Embase and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines with predetermined criteria, namely Ménière's disease, post-gadolinium magnetic resonance imaging and endolymphatic hydrops. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess bias. RESULTS: Eleven studies were included; they all used 3T magnetic resonance imaging, with three-dimensional fluid-attenuated inversion recovery being the most common sequence. Intravenous gadolinium administration was more widely used compared with the intratympanic route. As for the timing of acquisition, 4 hours post-administration was universally used for the IV gadolinium and 24 hours was used for the intratympanic gadolinium. Despite patient-selection associated bias, all studies reported adequate visualisation of the endolymphatic spaces. CONCLUSION: The use of delayed-acquisition magnetic resonance imaging is increasingly supported in visualising the endolymphatic spaces in Ménière's disease. Although the accessibility of 3T magnetic resonance imaging questions its wider applicability, it is a promising tool for the near future.

A systematic review and meta-analysis of prophylactic medication of vestibular migraine.

OBJECTIVE: Vestibular migraine is in the process of recognition as an individual clinical entity. At present, no guidelines exist for its management. This study aimed to conduct a systematic review and meta-analysis to determine the effectiveness of available prophylactic medication. METHOD: A literature search was performed using PubMed, Ovid and Embase databases. Qualitative and quantitative analysis were performed as well as risk of bias analysis. Meta-analysis for the mean differences for pre- and post-treatment impact based on Dizziness Handicap Inventory and Vertigo Symptom Scale were performed. Proportionate transformation meta-analysis for the successful event rate based on complete symptoms control was explored. RESULTS: Thirteen publications were identified: 3 were randomised, controlled trials and 10 were non-randomised, controlled trials. Propranolol and venlafaxine improved the Vertigo Symptom Scale score by -13.31 points and -4.16 points, respectively, and the Dizziness Handicap Inventory score by -32.24 and -21.24, respectively. Only propranolol achieved statistically significant impact with 60 per cent of patients achieving complete symptom control. CONCLUSION: Propranolol should be offered as the first-line treatment for vestibular migraine followed by venlafaxine. Amitriptyline, flunarizine and cinnarizine showed a trend for symptom improvement, but this was not statistically significant.

Six-canal video head impulse test in patients with labyrinthine and retrolabyrinthine pathology: detecting vestibulo-ocular reflex deficits.

BACKGROUND: Abnormal gains in six-canal video head impulse test are attributed to semi-circular canal deficits. However, as video head impulse test responses are linked to the vestibulo-ocular reflex, it was hypothesised that abnormal gains can be caused by vestibulo-ocular reflex pathway deficits. METHODS: This study compared video head impulse test gains in 20 patients with superior semi-circular canal dehiscence (labyrinthine cause) and 20 side- and gender-matched patients with vestibular schwannomas (retrolabyrinthine cause), and investigated correlations between them (Mann-Kendall trend test). RESULTS: Vestibular schwannoma but not superior semi-circular canal dehiscence was significantly associated with abnormal lateral (odds ratio = 9.00 (95 per cent confidence interval = 1.638-49.44), p = 0.011) and posterior (odds ratio = 9.00 (95 per cent confidence interval = 2.151-37.659), p = 0.003) canal status. In vestibular schwannoma patients, there was a statistically significant degree of dependence between all ipsilesional canal video head impulse test gains; such dependence was not observed in superior semi-circular canal dehiscence. CONCLUSION: Vestibulo-ocular reflex gains differ in patients with labyrinthine and retrolabyrinthine disease; this suggests that abnormal gains can indicate deficits not only in the semi-circular canals but also elsewhere along the vestibulo-ocular reflex pathway.

Incidental findings on magnetic resonance imaging of the internal auditory meatus for vestibular schwannoma: a systematic review.

OBJECTIVE: Magnetic resonance imaging of the internal auditory meatus is a highly sensitive and specific way to diagnose vestibular schwannoma. However, the rate of incidental findings with this method is believed to be high and can lead to increased patient anxiety and health interventions with unclear benefit. METHOD: A systematic review of the literature was performed using the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify incidental findings from magnetic resonance imaging of the internal auditory meatus; 12 studies were identified for inclusion within this review. RESULTS: A total of 10 666 patients were included within the review. The overall rate of diagnosis of vestibular schwannoma was 0.87 per cent; 21 per cent of the study population had incidental findings on magnetic resonance imaging of the internal auditory meatus, and 9.56 per cent had clinically significant incidental findings. CONCLUSION: Standardised pre-scan counselling may mitigate the risks of overdiagnosis, but future work should be undertaken to assess the benefits of such a strategy as well as the exact significance of some incidental findings.

Superior semicircular canal dehiscence: a narrative review.

BACKGROUND: Described just over 20 years ago, superior semicircular canal dehiscence remains a relatively unknown and easily missed cause of dizziness and auditory symptoms. OBJECTIVE: This review focused on the origin, presenting symptoms and underlying pathophysiology of superior semicircular canal dehiscence, and the available treatment options. MAIN FINDINGS AND CONCLUSION: The bony dehiscence acts as a 'third window', affecting inner-ear homeostasis, and resulting in hypersensitivity and a vestibular response to lower sound level stimuli. The third window effect explains the pressure- and sound-induced vertigo, oscillopsia, and nystagmus, as well as autophony, conductive hyperacusis and tinnitus. The origin of superior semicircular canal dehiscence is linked to the combination of a congenital or developmental factor, and a 'second event' like head trauma, rapid pressure changes or age-related factors. Computed tomography of the temporal bone and reduced vestibular-evoked myogenic potential thresholds can confirm the diagnosis. Despite only retrospective cohorts, surgery is considered a safe treatment option, targeting mainly vestibular but also auditory symptoms, with transmastoid approaches gaining popularity.

Growing versus non-growing vestibular schwannomas: assessment of natural history.

OBJECTIVE: Vestibular schwannomas can demonstrate great heterogeneity in their behaviour; approximately one-third will grow and two-thirds will not. This study aimed to determine whether there are factors present at diagnosis that can help predict outcomes. METHODS: This retrospective cohort study compared data from 735 patients from the past 20 years. Analysis of serial magnetic resonance imaging was carried out to place patients into growing and non-growing cohorts. Factors including size, age, follow-up time and presence of balance symptoms were compared. RESULTS: The median size of a growing vestibular schwannoma at diagnosis was 13 mm, whereas the non-growing median size was 10.65 mm (p < 0.001). Balance symptoms were present in 60.76 per cent of growing vestibular schwannoma patients but only in 38.75 per cent of patients with non-growing vestibular schwannomas (p < 0.001). CONCLUSION: This study highlights initial tumour size and balance symptoms as potential predictors of whether or not a vestibular schwannoma will grow; these results better facilitate our understanding of vestibular schwannoma natural history.

Low accuracy of 1.5 Tesla magnetic resonance imaging in identification of the bony defect in patients with superior semi-circular canal dehiscence syndrome: case-control study.

OBJECTIVE: To determine the accuracy of 1.5 Tesla magnetic resonance imaging in identifying the bony defect in superior semi-circular canal dehiscence syndrome. METHODS: A retrospective case-control study was conducted in tertiary university settings. The study included 12 patients with a definite diagnosis of superior semi-circular canal dehiscence syndrome and a control group comprising 12 non-superior semi-circular canal dehiscence syndrome patients, all with available magnetic resonance imaging data. The imaging scans were anonymised, and reviewed blindly and independently by three experienced radiologists. RESULTS: There was low sensitivity and specificity, with average values of 47 per cent (range, 16.7-66.7 per cent) and 69 per cent (range, 66.7-75 per cent) respectively. Cohen's kappa was 0.75, indicating substantial inter-rater reliability. CONCLUSION: Given the low accuracy of 1.5T magnetic resonance imaging in identifying the bony defect in superior semi-circular canal dehiscence syndrome, despite its value in inner-ear imaging, computed tomography or equivalent should be used when superior semi-circular canal dehiscence syndrome is suspected.

Triple semicircular canal occlusion: a surgical perspective with short- and long-term outcomes.

OBJECTIVE: To determine the short- and long-term outcomes of triple semicircular canal occlusion as a potential alternative for patients with intractable Ménière's disease. METHODS: A retrospective case series was performed in university settings, enrolling patients with intractable Ménière's disease with previous maximum treatment, who underwent transmastoid, triple semicircular canal occlusion. The study documented: pre- and post-operative Dizziness Handicap Inventory scores at six weeks and one year post-treatment, pure tone audiometry, and surgical aspects. RESULTS: Two female patients, aged 42 and 65 years, underwent unilateral three-semicircular-canal occlusion. Their respective Dizziness Handicap Inventory scores improved from 88 to 68 and 54 to 30 at six weeks post-operatively, with scores of 66 and 0 at one year post-treatment. The one patient with pre-existing functional hearing maintained her hearing threshold post-operatively. CONCLUSION: Triple semicircular canal occlusion is a safe, hearing-preserving, extracranial alternative technique that can control rotatory vertigo in patients with intractable Ménière's disease, when other measures have failed.

An observational study of T2-weighted white matter hyperintensities on magnetic resonance imaging of the internal auditory meatus and brain: ignore or not?

BACKGROUND: Magnetic resonance imaging of the internal auditory meatus frequently detects incidental white matter hyperintensities. This study investigated the association between these and the risk of stroke and transient ischaemic attack, or myocardial infarction. METHODS: The records of patients with incidental white matter hyperintensities were reviewed, and data were collected on: age, sex, cardiovascular risk factors, and incidence of stroke and transient ischaemic attack, or myocardial infarction, five years later. The risk factors associated with vascular events were explored. RESULTS: Of 6978 patients, 309 (4.4 per cent) had incidental white matter hyperintensities. Of these, 20 (6.5 per cent) had a stroke or transient ischaemic attack within five years, and 5 (1.7 per cent) had a myocardial infarction. The number of cardiovascular risk factors was significantly associated with the incidence of stroke and transient ischaemic attack (p = 0.004), and myocardial infarction (p = 0.023). CONCLUSION: The number of cardiovascular risk factors predicts the likelihood of vascular events; appropriate risk factor management is recommended for patients with incidental white matter hyperintensities of presumed vascular origin.

Association between socioeconomic indicators and geographic distribution of vestibular schwannomas in West Scotland: a 15-year review.

OBJECTIVE: Socioeconomic risk factors may contribute to geographic variation in diseases, but studies are limited due to lack of large available cohorts. METHOD: A geographic analysis was performed of the association between socioeconomic risk factors and the distribution of vestibular schwannomas in adults diagnosed with sporadic vestibular schwannomas through the National Health Services in the West of Scotland from 2000 to 2015. RESULTS: A total of 511 sporadic vestibular schwannomas were identified in a population of over 3.1 million. Prevalence of vestibular schwannomas were lowest in cases with good health (-0.64, 95 per cent confidence interval: -0.93,-0.38; p = 0.002) and level 1 qualifications (-0.562, 95 per cent confidence interval: -0.882 to -0.26; p = 0.01). However, these risk factors did not demonstrate consistent linearity of correlations. Prevalence was lower in people originating from European Union accession countries from April 2001 to March 2011 (-0.63, 95 per cent confidence interval: -0.84 to -0.43; p = 0.002). No correlation between distribution of vestibular schwannomas and socioeconomic risk factors met our threshold criteria (± 0.7). CONCLUSION: This study demonstrated that there is little variation in distribution of vestibular schwannomas by socioeconomic risk factors.

Potential association between recurrent facial nerve palsy and migraines.

OBJECTIVE: This study aimed to investigate the possible association between recurrent facial nerve palsy and migraines. METHOD: This study was a prospective case series with a two-year follow-up at an academic, tertiary referral centre and included patients with at least four episodes of recurrent lower motor neuron facial nerve palsy. All patients underwent standardised diagnostic tests. RESULTS: Four patients fulfilled the inclusion criteria. The patients were all female with an average age at presentation of 40.75 years (range, 33-60 years) and an average age at the initial episode of 14 years (range, 12-16 years). The number of episodes varied between six and nine. All patients had at least one episode of facial nerve palsy on the contralateral side. Two patients were diagnosed and treated for migraine with aura remaining asymptomatic following prophylactic medication for migraines. CONCLUSION: The results raise the possibility of an association between recurrent facial nerve palsy and migraines. Prospective studies in patients with even fewer episodes of facial nerve palsy could shed more light on this association.

Arachnoid cysts on magnetic resonance imaging: just an incidental finding?

OBJECTIVE: To determine the clinical significance of arachnoid cysts. METHODS: The scans of 6978 patients undergoing magnetic resonance imaging of the internal acoustic meatus for unilateral cochleovestibular symptoms were retrospectively reviewed. We identified the scans with arachnoid cysts, and assessed the statistical associations between the laterality, location and size of the arachnoid cyst, the laterality of symptoms, the patients' age and gender. RESULTS: In a total of 37 arachnoid cysts identified in 36 patients (0.5 per cent), no associations were identified between the laterality of symptoms and the laterality of the arachnoid cyst, regardless of its size or location. There were no significant associations between the location of the arachnoid cyst and the age (p = 0.99) or gender of the patient (p = 0.13), or size (p = 0.656) or side of the cyst (p = 0.61). None of the cysts with repeat imaging scans (17 cysts) demonstrated growth. CONCLUSION: Our results suggest that most, if not all, arachnoid cysts are of no clinical significance. Given their indolent behaviour, even serial imaging is not essential.

Benefits of pre-labyrinthectomy intratympanic gentamicin: contralateral vestibular responses.

OBJECTIVE: To determine the impact of pre-operative intratympanic gentamicin injection on the recovery of patients undergoing translabyrinthine resection of vestibular schwannomas. METHODS: This prospective, case-control pilot study included eight patients undergoing surgical labyrinthectomy, divided into two groups: four patients who received pre-operative intratympanic gentamicin and four patients who did not. The post-operative six-canal video head impulse test responses and length of in-patient stay were assessed. RESULTS: The average length of stay was shorter for patients who received intratympanic gentamicin (6.75 days; range, 6-7 days) than for those who did not (9.5 days; range, 8-11 days) (p = 0.0073). Additionally, the gentamicin group had normal post-operative video head impulse test responses in the contralateral ear, while the non-gentamicin group did not. CONCLUSION: Pre-operative intratympanic gentamicin improves the recovery following vestibular schwannoma resection, eliminating, as per the video head impulse test, the impact of labyrinthectomy on the contralateral labyrinth.

Cochlear patency following translabyrinthine vestibular schwannoma resection: implications for hearing rehabilitation.

OBJECTIVE: To examine when cochlear fibrosis occurs following a translabyrinthine approach for vestibular schwannoma resection, and to determine the safest time window for potential cochlear implantation in cases with a preserved cochlear nerve. METHODS: This study retrospectively reviewed the post-operative magnetic resonance imaging scans of patients undergoing a translabyrinthine approach for vestibular schwannoma resection, assessing the fluid signal within the cochlea. Cochleae were graded based on the Isaacson et al. system (from grade 0 - no obstruction, to grade 4 - complete obliteration). RESULTS: Thirty-nine patients fulfilled the inclusion criteria. The cochleae showed no evidence of obliteration in: 75 per cent of patients at six months, 38.5 per cent at one year and 27 per cent beyond one year. Most changes happened between 6 and 12 months after vestibular schwannoma resection, with cases of an unobstructed cochlear decreasing dramatically, from 75 per cent to 38.5 per cent, within this time. CONCLUSION: The progress of cochlear obliteration that occurred between 6 and 12 months following vestibular schwannoma resection indicates that the first 6 months provides a safer time window for cochlear patency.

Geniculate neuralgia: a systematic review.

OBJECTIVE: To systematically summarise the peer-reviewed literature relating to the aetiology, clinical presentation, investigation and treatment of geniculate neuralgia. DATA SOURCES: Articles published in English between 1932 and 2012, identified using Medline, Embase and Cochrane databases. METHODS: The search terms 'geniculate neuralgia', 'nervus intermedius neuralgia', 'facial pain', 'otalgia' and 'neuralgia' were used to identify relevant papers. RESULTS: Fewer than 150 reported cases were published in English between 1932 and 2012. The aetiology of the condition remains unknown, and clinical presentation varies. Non-neuralgic causes of otalgia should always be excluded by a thorough clinical examination, audiological assessment and radiological investigations before making a diagnosis of geniculate neuralgia. Conservative medical treatment is always the first-line therapy. Surgical treatment should be offered if medical treatment fails. The two commonest surgical options are transection of the nervus intermedius, and microvascular decompression of the nerve at the nerve root entry zone of the brainstem. However, extracranial intratemporal division of the cutaneous branches of the facial nerve may offer a safer and similarly effective treatment. CONCLUSION: The response to medical treatment for this condition varies between individuals. The long-term outcomes of surgery remain unknown because of limited data.