This research aimed to print realistically detailed and magnified three-dimensional models of the inner ear, specifically focusing on visualising its complex labyrinth structure and functioning simulation.

Temporal bone computed-tomography data were imported into Mimics software to construct an initial three-dimensional inner-ear model. Subsequently, the model was amplified and printed with precision using a three-dimensional printer. Five senior attending physicians evaluated the printed model using a Likert scale to gauge its morphological accuracy, clinical applicability and anatomical teaching value.

The printed inner-ear model effectively demonstrated the intricate internal structure. All five physicians agreed that the model closely resembled the real inner ear in shape and structure, and simulated certain inner-ear functions. The model was considered highly valuable for understanding anatomical structure and disorders.

The three-dimensionally printed inner-ear model is highly simulated and provides a valuable visual tool for studying inner-ear anatomy and clinical teaching, benefiting otologists.

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.

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).

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.

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.

To determine the accuracy of 1.5 Tesla magnetic resonance imaging in identifying the bony defect in superior semi-circular canal dehiscence syndrome.

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.

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.

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.

Described just over 20 years ago, superior semicircular canal dehiscence remains a relatively unknown and easily missed cause of dizziness and auditory symptoms.

This review focused on the origin, presenting symptoms and underlying pathophysiology of superior semicircular canal dehiscence, and the available treatment options.

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.

To determine the impact of pre-operative intratympanic gentamicin injection on the recovery of patients undergoing translabyrinthine resection of vestibular schwannomas.

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.

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.

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.

Benign paroxysmal positional vertigo and migraine-associated dizziness are common. The prevalence of benign paroxysmal positional vertigo seems to be higher in patients with migraine-associated dizziness than in those without migraine.

A database of 508 patients seen at the primary author's balance clinic was analysed to determine the prevalence of migraine, as defined by International Headache Society criteria, in patients with benign paroxysmal positional vertigo.

The percentage of patients with dizziness or vertigo who met criteria for migraine was 33.7 per cent, with a prevalence of benign paroxysmal positional vertigo of 42.3 per cent. When excluding patients with migrainous vertigo, patients with migraine frequently had benign paroxysmal positional vertigo (66.7 per cent vs 55.8 per cent), although this finding was not statistically significant.

The results for the entire sample suggest that, after excluding patients with migrainous vertigo, patients with migraine seem more likely to have benign paroxysmal positional vertigo; however, this association was not significant, probably because of the small sample size.

To determine whether the distribution of membrane lesions associated with Ménière's disease is random, as might be expected from a pervasive process such as hydrops, or orderly, as might be expected if membrane resistance is graded.

A meta-analysis of temporal bone reports on 184 specimens demonstrating endolymphatic hydrops was undertaken to determine membrane lesion evolution and distribution.

Lesion distribution was found to be orderly and cochleocentric. No random scattershot lesions were reported in any study. Disease always started in the cochlear apex, even in non-symptomatic cases, and then involved the saccule, utricle, ampullae and canal system in that precise sequence as the disease progressed.

The orderly lesion progression in the otopathology associated with Ménière's disease suggests that the hydropic process has a graded non-random effect on the labyrinth. These findings suggest a pathological staging system that may be useful in temporal bone evaluation.

To establish a new magnetic resonance imaging scoring system for diagnosing endolymphatic hydrops.

A total of 214 ears of 107 patients were categorised into five groups: no symptoms, Ménière's disease, sudden deafness, delayed endolymphatic hydrops and other ear disorders. Gadolinium distribution within the labyrinth was scored separately and quantitatively by two radiologists. Multiple independent-sample non-parametric tests, Bayesian discriminant analysis, multivariate logistic regression and receiver operating characteristic curve analyses were performed.

The derived scoring model was highly accurate for diagnosing Ménière's disease and delayed endolymphatic hydrops. Two magnetic resonance imaging scoring methods for the perilymphatic space were proposed for the diagnosis of endolymphatic hydrops: a pre-1 value (a new variable that predicts individual probability) of more than 0.3982299, or a sum of all labyrinth component scores of less than 14.5.

A convenient method is proposed which offers reliable radiological diagnostic criteria for Ménière's disease and delayed endolymphatic hydrops.

Cochlear implantation has been used to rehabilitate profoundly deafened adults for more than 25 years. However, surgical labyrinthectomy is often considered a contraindication to cochlear implantation, especially if there is a significant delay between the two procedures. As the role of cochlear implantation continues to expand, this idea requires reconsideration.

A 59-year-old woman presented to our clinic after undergoing bilateral surgical labyrinthectomies for intractable Ménière's disease 21 years prior. Despite the significant time delay, she underwent cochlear implantation with a good audiological outcome and improved quality of life.

Changes to the cochlea and vestibule following surgical labyrinthectomy include cochlear ossification and obliteration of the vestibule. These issues have been thought to limit the potential for cochlear implantation, especially when there is a significant delay between the two procedures. However, delayed cochlear implantation, even decades after labyrinthectomy, remains a viable treatment option which can benefit selected patients.