What is the most important factor to preserve hearing in lateral semicircular canal fistula surgeries, fistula size or bony structure?

PURPOSE: Cholesteatoma on lateral semicircular canal (LSCC) fistula > 2 mm in size is likely to be unmanipulated due to the risk of sensorineural hearing loss. However, the matrix can be successfully removed without hearing loss when it is > 2 mm. The purpose of the study was to evaluate surgical experience over the past 10 years and to suggest the important factor for the hearing preservation in LSCC fistula surgeries. METHODS: According to the fistula size and symptoms, 63 patients with LSCC fistula were grouped as follows: Type I (fistula < 2 mm), Type II (≥ 2 mm and < 4 mm without vertigo), Type III (≥ 2 mm and < 4 mm with vertigo), Type IV (≥ 4 mm), and Type V (any size fistula but with deafness at the initial visit). The cholesteatoma matrix was meticulously manipulated and removed by experienced surgeons. RESULTS: Only two patients completely lost their hearing after surgery (4.5%). However, the loss was inevitable because their cholesteatomas were highly invasive and there was also facial nerve canal involvement; thus, the bony structure of the LSCC was already destroyed by the cholesteatoma. Unlike these two Type IV patients, Type I-III patients, and those with a fistula size < 4 mm, did not lose their sensorineural hearing. If the structure of the LSCC was maintained, hearing loss did not occur even if the fistula size ≥ 4 mm. CONCLUSIONS: The preservation of the labyrinthine structure is more important than the defect size of the LSCC fistula. If the structure is intact, cholesteatoma matrices lying on the defect can be safely removed, even though the size of bony defect is large.

Facial canal dehiscence, dural exposure, and labyrinthine fistula in middle ear cholesteatoma and mastoiditis.

PURPOSE: To analyze the prevalence and associations of facial canal dehiscence (FCD), dural exposure, and labyrinthine fistula in chronic otitis media (COM) with and without cholesteatoma. METHODS: This was a retrospective study performed in an academic medical center. Patients who received tympanoplasty with mastoidectomy for COM with and without cholesteatoma were included. The prevalence of FCD, dural exposure, and labyrinthine fistula in COM with and without cholesteatoma (mastoiditis) and their relationships were analyzed. RESULTS: A total of 189 patients, including 107 (56.6%) females and 82 (43.4%) males, with 191 ears were included. There were 149 cases (78.0%) of cholesteatoma and 42 patients (22.0%) with mastoiditis. FCD was noted in 27.5% of patients with cholesteatoma and 9.5% of patients with mastoiditis. Dural exposure was found in 21 patients (14.1%) with cholesteatoma and 4 patients (9.5%) with mastoiditis. Eleven patients (7.4%) with cholesteatoma and 1 patient (2.4%) with mastoiditis had labyrinthine fistula. Patients with a labyrinthine fistula had nearly a fivefold greater chance (OR = 4.924, 95% CI = 1.355-17.896, p = 0.015) of having FCD than those without a fistula. There was a positive correlation between dural exposure and labyrinthine fistula (P = 0.011, Fisher's exact test). CONCLUSION: FCD, dural exposure, and labyrinthine fistula are common complications in COM. These complications are more frequently observed in patients with cholesteatoma than in patients with mastoiditis. Surgeons should pay more attention to the treatment of COM.

Post-operative hearing among patients with labyrinthine fistula as a complication of cholesteatoma using "under water technique".

INTRODUCTION: During surgery in patients with labyrinthine fistula the mandatory complete removal of the cholesteatoma while preserving inner ear and vestibular function is a challenge. Options so far have been either the complete removal of the cholesteatoma or leaving the matrix on the fistula. We evaluated an alternative "under water" surgical technique for complete cholesteatoma resection, in terms of preservation of postoperative inner ear and vestibular function. METHODS: From 2013 to 2019, 20 patients with labyrinthine fistula due to cholesteatoma were operated. We used the canal wall down approach and removal of matrix on the fistula was done as the last step during surgery using the "under water technique". The pre and postoperative hearing tests and the vestibular function were retrospectively examined. RESULTS: There was no significant difference between pre and post-operative bone conduction thresholds; 20% experienced an improvement of more than 10 dB, with none experiencing a postoperative worsening of sensorineural hearing loss. Among seven patients who presented with vertigo, two had transient vertigo postoperatively but eventually recovered. CONCLUSION: Our data show that the "under water technique" for cholesteatoma removal at the labyrinthine fistula is a viable option in the preservation of inner ear function and facilitating complete cholesteatoma removal.

A case of perilymphatic fistula caused by surgical drilling with preserved normal hearing.

We introduce our horrible experience of lateral semicircular canal exposure due to unintended drilling during left facial nerve decompression. Nearly half of the canal was drilled-out, however, the membranous labyrinth was preserved and the defect was covered with temporal fascia. Immediately after surgery, the patient complained of vertigo with right beating nystagmus. However, the patient could hear an audible tuning fork sound and the Weber-test showed left-sided deviation. The vertigo gradually subsided and the facial palsy was completely recovered 3 months after the surgery. One and half years later, the patient spent a normal life with normal hearing nevertheless after this terrifying episode.

CT and MRI for the diagnosis of perilymphatic fistula: a study of 17 surgically confirmed patients.

BACKGROUND: We evaluated the usefulness of CT and MRI for the diagnosis of perilymphatic fistula (PLF) of the round (RW) and/or oval (OW) windows, with surgery as gold standard. METHODS: We retrospectively enrolled 17 patients who presented a surgically confirmed PLF of the round (RW) or oval (OW) windows. All patients were imaged by CT + MRI (T2W SSFP without contrast) prior to surgery (= gold standard). Two radiologists, analyzed the RW and OW on the side of the clinical symptoms and sensitivity (Se) + Specificity (Sp) were calculated. RESULTS: Round window fistula was the most frequent (71%). The best sign of PLF on imaging was a fluid filling of the window niches, which had good Se (83-100% for RW, 66-83% for OW) and Sp (60% for RW, 91-100% for OW). Disorientation of the footplate and pneumolabyrinth were also only observed in 50% of OW PLF. CONCLUSION: The combination of CT and MRI is a reliable tool for a fast and accurate diagnosis of round and oval window perilymphatic fistula, with good sensitivity (> 80%). The most common sign of PLF on imaging is the presence of a fluid-filling in the RW (especially if > 2/3 of the RW niche) or in the OW niches on both CT and MRI. A disorientation of the footplate or the presence of a pneumolabyrinth are clearly in favor of an oval window perilymphatic fistula.

Can miR-34a be suitable for monitoring sensorineural hearing loss in patients with mitochondrial disease? A case series.

Purpose: We aimed at evaluating the feasibility of using MicroRNA (miR)-34a and miR-29b to detect inner ear damage in patients with mitochondrial disease (MD) and sensorineural hearing loss (SNHL).Material and Methods: Three patients with MD and SNHL and seven healthy control subjects were included in this case series. MD patients underwent pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE) and auditory brain response tests to investigate the specific cochlear and retrocochlear functions; control patients underwent PTA. MiR-34a and miR-29b were extracted from blood in all subjects included in the study. The expression of miR-34a and miR-29b in MD patients and healthy controls were statistically compared, then the expression of these two miRs was compared with DPOAE values.Results: In MD patients, miR-34a was significantly up-regulated compared to healthy controls; miR-34a and DPOAEs were negatively correlated. Conversely, miR-29b was up-regulated only in the youngest patient who suffered from the mildest forms of MD and SNHL, and negatively correlated with DPOAEs.Conclusion: In MD patients, miR-34a and miR-29b might be a marker of inner ear damage and early damage, respectively. Additional studies on larger samples are necessary to confirm these preliminary results.

Post-traumatic pneumolabyrinth: a rare cause of hearing loss.

Pneumolabyrinth (PL) is the presence of air within the vestibule, semicircular canals, or cochlea. It represents an abnormal connection between the inner ear and middle ear spaces. PL most commonly occurs after blunt head trauma, followed by penetrating injuries. Temporal fractures may or may not accompany. Prognosis of hearing loss is poor, while prognosis of vestibular symptoms is good. Herein we present a 45-year-old female with unilateral pneumolabyrinth, who presented with significant dizziness and unilateral total hearing loss after a car accident.

Loss of MAFB Function in Humans and Mice Causes Duane Syndrome, Aberrant Extraocular Muscle Innervation, and Inner-Ear Defects.

Duane retraction syndrome (DRS) is a congenital eye-movement disorder defined by limited outward gaze and retraction of the eye on attempted inward gaze. Here, we report on three heterozygous loss-of-function MAFB mutations causing DRS and a dominant-negative MAFB mutation causing DRS and deafness. Using genotype-phenotype correlations in humans and Mafb-knockout mice, we propose a threshold model for variable loss of MAFB function. Postmortem studies of DRS have reported abducens nerve hypoplasia and aberrant innervation of the lateral rectus muscle by the oculomotor nerve. Our studies in mice now confirm this human DRS pathology. Moreover, we demonstrate that selectively disrupting abducens nerve development is sufficient to cause secondary innervation of the lateral rectus muscle by aberrant oculomotor nerve branches, which form at developmental decision regions close to target extraocular muscles. Thus, we present evidence that the primary cause of DRS is failure of the abducens nerve to fully innervate the lateral rectus muscle in early development.

Computed tomographic characteristics of pneumolabyrinth in a French bulldog with otitis media and externa.

A four-year-old female French bulldog was presented for evaluation of acute, left-sided peripheral vestibular syndrome. Computed tomographic (CT) examination of the head revealed the presence of air within the left cochlea and vestibule, consistent with pneumolabyrinth. This was concurrent with ipsilateral otitis media and externa. Pneumolabyrinth is an uncommon finding in humans and is most frequently due to head trauma and temporal bone fracture. This is the first report describing pneumolabyrinth in a dog, apparently of nontraumatic origin in this case.

A narrative review of obesity and hearing loss.

The comorbidities related to obesity are already extensive, but as the prevalence of obesity increases globally, so do the number of its associated conditions. The relationship between hearing impairment and obesity is a relatively recent research interest, but is significant as both conditions have the ability to substantially reduce an individual's quality of life both physically and psychologically. Obesity has a significant effect on vascular function, and this may have an impact on highly vascular organs such as the auditory system. This review aims to provide an overview of the existing literature surrounding the association between hearing loss and obesity, in order to emphasise these two highly prevalent conditions, and to identify areas of further investigation. Our literature search identified a total of 298 articles with 11 articles of relevance to the review. The existing literature in this area is sparse, with interest ranging from obesity and its links to age-related hearing impairment (ARHI) and sudden sensorineural hearing loss (SSNHL), to animal models and genetic syndromes that incorporate both disorders. A key hypothesis for the underlying mechanism for the relationship between obesity and hearing loss is that of vasoconstriction in the inner ear, whereby strain on the capillary walls due to excess adipose tissue causes damage to the delicate inner ear system. The identified articles in this review have not established a causal relationship between obesity and hearing impairment. Further research is required to examine the emerging association between obesity and hearing impairment, and identify its potential underlying mechanisms.

Management of labyrinthine fistula: hearing preservation versus prevention of residual disease.

The objective of the study was to evaluate postoperative hearing and disease control after cholesteatoma surgery for labyrinthine fistulas. In a retrospective cohort study, we evaluated a consecutive cohort comprising 44 patients (45 ears) with labyrinthine fistulas associated with chronic otitis media with cholesteatoma who underwent surgery between 2002 and 2015. We looked at patient characteristics, pre- and postoperative bone conduction thresholds (BCT), operative approach and findings, extent of disease and the occurrence of residual disease. All deaf ears (24%) presented preoperatively with a large fistula. Opening the membranous labyrinth resulted in significantly worse postoperative BCT (p = 0.01). Neither the present study nor a literature search revealed a significant positive effect of corticosteroids on postoperative hearing preservation. Large fistulas were correlated with poorer preoperative BCTs, but not with poorer postoperative BCTs. Opening the membranous labyrinth during surgery is correlated with poorer postoperative BCTs and can be seen as a predictive parameter. The use of corticosteroids in the perioperative management of labyrinthine fistula was not found to result in any improvement in postoperative BCTs.

Intracochlear drug delivery in combination with cochlear implants : Current aspects.

Local drug application to the inner ear offers a number of advantages over systemic delivery. Local drug therapy currently encompasses extracochlear administration (i. e., through intratympanic injection), intracochlear administration (particularly for gene and stem cell therapy), as well as various combinations with auditory neurosensory prostheses, either evaluated in preclinical or clinical studies, or off-label. To improve rehabilitation with cochlear implants (CI), one focus is the development of drug-releasing electrode carriers, e. g., for delivery of glucocorticosteroids, antiapoptotic substances, or neurotrophins to the inner ear. The performance of cochlear implants may thus be improved by protecting neuronal structures from insertion trauma, reducing fibrosis in the inner ear, and by stimulating growth of neuronal structures in the direction of the electrodes. Controlled drug release after extracochlear or intracochlear application in conjunction with a CI can also be achieved by use of a biocompatible, resorbable controlled-release drug-delivery system. Two case reports for intracochlear controlled release drug delivery in combination with cochlear implants are presented. In order to treat progressive reduction in speech discrimination and increased impedance, two cochlear implant patients successfully underwent intracochlear placement of a biocompatible, resorbable drug-delivery system for controlled release of dexamethasone. The drug levels reached in inner ear fluids after different types of local drug application strategies can be calculated using a computer model. The intracochlear drug concentrations calculated in this way were compared for different dexamethasone application strategies.

Vestibular evoked myogenic potentials in patients with ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease with unknown etiology. Although sacroiliac joint involvement is the classic sign along with the formed immune mediators, it may result in immune-mediated inner ear disease and may cause damage to the audiovestibular system. Vestibular evoked myogenic potentials (VEMP) is a clinical reflex test used in the diagnosis of vestibular diseases and is performed by recording and evaluating the muscle potentials resulting from the stimulation of the vestibular system with different stimuli. The aim of this study is to evaluate the cervical VEMP test results in AS patients without vestibular symptoms. Thirty-three patients with AS and a control group of 30 healthy volunteers with similar demographic characteristics were evaluated in the study. VEMP wave latency, P13-N23 wave amplitude, and VEMP asymmetry ratio (VAR) values were compared between the groups. The relationship between clinical and laboratory findings of the AS patients and VEMP data were also investigated. Compared with healthy people, this study shows the response rate of patients with ankylosing spondylitis was reduced in the VEMP test, and P13-N23 wave amplitude showed a decrease in AS patients who had VEMP response (p < 0.001). There was no correlation between the clinical and laboratory findings and VEMP findings in patients with ankylosing spondylitis. The data obtained from this study suggest that AS may lead to decreased sensitivity of the vestibular system.

Lateral semicircular canal fistula in cholesteatoma: diagnosis and management.

The objective of this retrospective study was to present the authors' experience on the management of labyrinthine fistula secondary to cholesteatoma. 695 patients, who underwent tympanoplasty for cholesteatoma, in a University Hospital between 1993 and 2013 were reviewed, to select only those with labyrinthine fistulas. 42 patients (6%) had cholesteatoma complicated by fistula of the lateral semicircular canal (LSCC). The following data points were collected: symptoms, pre- and postoperative clinical signs, surgeon, CT scan diagnosis, fistula type, surgical technique, preoperative vestibular function and audiometric outcomes. Most frequent symptoms were unspecific, such as otorrhea, hearing loss and dizziness. However, preoperative high-resolution computed tomography predicted fistula in 88 %. Using the Dornhoffer and Milewski classification, 16 cases (38 %) were identified as stage 1, 22 (52 %) as stage II, and 4 (10 %) as stage III. The choice between open or closed surgical procedure was independent of the type of fistulae. The cholesteatoma matrix was completely removed from the fistula and immediately covered by autogenous material. In eight patients (19 %), the canal was drilled with a diamond burr before sealing with autologous tissue. After surgery, hearing was preserved or improved in 76 % of the patients. There was no statistically significant relationship between the extent of the labyrinthine fistula and the hearing outcome. In conclusion, a complete and nontraumatic removal of the matrix cholesteatoma over the fistula in a one-staged procedure and its sealing with bone dust and fascia temporalis, with sometimes exclusion of the LSCC, is a safe and effective procedure to treat labyrinthine fistula.

[The role of computer and magnetic resonance imaging in patients with deafness]. / Rol' komp'yuternoi i magnitno-rezonansnoi tomografii u patsientov s glukhotoi.

The objective of the present study was to evaluate the potential of CT and MRI for diagnostics of congenital and acquired pathology of the inner ear in the deaf patients. Two groups of the patients were examined. The first group consisted of 75 patients with congenital or acquired deafness etiology. The second group was comprised of 75 patients with deafness associated with acute bacterial meningitis suffered in the preceding period. All the patients were examined by CT and MRI of temporal bones. The results of the study provided a basis for the development of indications for the application of CT and MRI to examine the patients presenting with hearing loss and deafness. CONCLUSION: CT and MRI make it possible to identify individual features of the temporal bone structure significant for the surgical treatment. MRI appears to have an advantage over CT for diagnostics of early obliteration of the cochlea. Both CT and MRI are the optional methods for the examination of the patients with deafness developing after meningitis.

Endolymphatic sac involvement in bacterial meningitis.

The commonest sequelae of bacterial meningitis are related to the inner ear. Little is known about the inner ear immune defense. Evidence suggests that the endolymphatic sac provides some protection against infection. A potential involvement of the endolymphatic sac in bacterial meningitis is largely unaccounted for, and thus the object of the present study. A well-established adult rat model of Streptococcus pneumoniae meningitis was employed. Thirty adult rats were inoculated intrathecally with Streptococcus pneumoniae and received no additional treatment. Six rats were sham-inoculated. The rats were killed when reaching terminal illness or on day 7, followed by light microscopy preparation and PAS-Alcian blue staining. The endolymphatic sac was examined for bacterial invasion and leukocyte infiltration. Neither bacteria nor leukocytes infiltrated the endolymphatic sac during the first days. Bacteria invaded the inner ear through the cochlear aquaduct. On days 5-6, the bacteria invaded the endolymphatic sac through the endolymphatic duct subsequent to invasion of the vestibular endolymphatic compartment. No evidence of direct bacterial invasion of the sac through the meninges was found. Leukocyte infiltration of the sac occurred prior to bacterial invasion. During meningitis, bacteria do not invade the endolymphatic sac through the dura, but solely through the endolymphatic duct, following the invasion of the vestibular system. Leukocyte infiltration of the sac occurs prior to, as well as concurrent with bacterial invasion. The findings support the endolymphatic sac as part of an innate immune defense system protecting the inner ear from infection.

Current understanding of the pathogenesis of autoimmune inner ear disease: a review.

BACKGROUND: Autoimmune inner ear disease (AIED) is a poorly understood form of sensorineural hearing loss that causes bilateral, asymmetric, progressive hearing loss, sometimes with vestibular symptoms, often associated with a systemic autoimmune disease, which is noteworthy as the only sensorineural loss responsive to medical therapy. Despite much research interest of the past 25 years, its aetiopathogenesis is still unproven. OBJECTIVE OF REVIEW: To succinctly consolidate research and opinion regarding the pathogenesis of autoimmune inner ear disease, in ongoing efforts to elucidate the molecular and intracellular pathways that lead to inner ear damage, which may identify new targets for pharmacotherapy. TYPE OF REVIEW: Systematic review SEARCH STRATEGY: PubMed/MEDLINE search using key terms to identify articles published between January 1980 and Apr 2014. Additionally, any landmark works discussed in this body of literature were obtained and relevant information extracted as necessary. EVALUATION METHOD: Inclusion criterion was any information from animal or human studies with information relevant to possible aetiopathogenesis of AIED. Studies that focused on diagnosis, ameliorating symptoms or treatment, without specific information relevant to mechanisms of immune-mediated injury were excluded from this work. Articles meeting the inclusion criteria were digested and summarised. RESULTS: A proposed pathogenic mechanism of AIED involves inflammation and immune-mediated attack of specific inner ear structures, leading to an excessive Th1 immune response with vascular changes and tissue damage in the cochlea. Studies have identified self-reactive T cells and immunoglobulins, and have variously implicated immune-complex deposition, microthrombosis and electrochemical disturbances causing impaired neurosignalling in the pathogenesis of AIED. Research has also demonstrated abnormalities in the cytokine milieu in subjects with AIED, which may prove a target for therapy in the future. CONCLUSION: Ongoing research is needed to further elucidate the aetiopathogenesis of AIED and discern between various mechanisms of tissue injury. Large-cohort clinical studies employing IL-1 receptor blockade are warranted to determine its potential for future therapy.

Gravity-dependent nystagmus and inner-ear dysfunction suggest anterior and posterior inferior cerebellar artery infarct.

Cerebellar lesions may present with gravity-dependent nystagmus, where the direction and velocity of the drifts change with alterations in head position. Two patients had acute onset of hearing loss, vertigo, oscillopsia, nausea, and vomiting. Examination revealed gravity-dependent nystagmus, unilateral hypoactive vestibulo-ocular reflex (VOR), and hearing loss ipsilateral to the VOR hypofunction. Traditionally, the hypoactive VOR and hearing loss suggest inner-ear dysfunction. Vertigo, nausea, vomiting, and nystagmus may suggest peripheral or central vestibulopathy. The gravity-dependent modulation of nystagmus, however, localizes to the posterior cerebellar vermis. Magnetic resonance imaging in our patients revealed acute cerebellar infarct affecting posterior cerebellar vermis, in the vascular distribution of the posterior inferior cerebellar artery (PICA). This lesion explains the gravity-dependent nystagmus, nausea, and vomiting. Acute onset of unilateral hearing loss and VOR hypofunction could be the manifestation of inner-ear ischemic injury secondary to the anterior inferior cerebellar artery (AICA) compromise. In cases of combined AICA and PICA infarction, the symptoms of peripheral vestibulopathy might masquerade the central vestibular syndrome and harbor a cerebellar stroke. However, the gravity-dependent nystagmus allows prompt identification of acute cerebellar infarct.

[Cochleovestibular disorders in the patients suffering from migraine of the basilar type].

The objective of the present study was to improve diagnostics of basilar type migraine (BTM) based on the results of neurological, vestibulometric, and audiological studies of 11 patients. Peculiarities of the clinical picture of this disease and the medical histories of these patients are described. The pathogenetic role of labyrinthine hydrops and the difficulties encountered in diagnostics of Meniere's disease are discussed.