Cochlear and vestibular lesions in capsular otosclerosis as seen in microdissection

Comprehensive vestibular evaluation in patients with Otosclerosis: a case control study

Aim

Otosclerosis is one of the common otologic diseases. The mechanism and the probable site of vestibular involvement are not yet fully understood. The present study aimed to perform a comprehensive vestibular evaluation in patients with otosclerosis, compared to the cases without otosclerosis.

Materials and methods

patients underwent a comprehensive cochleovestibular evaluation, including audiometry, ocular and cervical vestibular evoked myogenic potential (o-VEMP and c-VEMP), video head impulse (vHIT) and caloric tests. The results were compared with those obtained from the non-otosclerosis control group.

Results

A total of 61 individuals were included in the study who were divided into two groups of the case (50.82%) and control (49.18%). The results showed that there was a significant difference in the mean vHIT gain between the case and control groups (P < 0.05). However, the mean gain was still within the normal range. Besides, the patients with otosclerosis had significant bilateral or unilateral weaknesses according to caloric test results. Moreover, their o-VEMP and c-VEMP results were significantly abnormal as well (P < 0.05).

Conclusion

Based on the results of the present study, the vestibular system even in asymptomatic cases, is affected by otosclerosis. Furthermore, it seems that the otolithic system has a higher chance of involvement, compared to the semicircular canals.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-022-03147-5.

Cochlear Surface Preparation in the Adult Mouse

Auditory processing in the cochlea depends on the integrity of the mechanosensory hair cells. Over a lifetime, hearing loss can be acquired from numerous etiologies such as exposure to excessive noise, the use of ototoxic medications, bacterial or viral ear infections, head injuries, and the aging process. Loss of sensory hair cells is a common pathological feature of the varieties of acquired hearing loss. Additionally, the inner hair cell synapse can be damaged by mild insults. Therefore, surface preparations of cochlear epithelia, in combination with immunolabeling techniques and confocal imagery, are a very useful tool for the investigation of cochlear pathologies, including losses of ribbon synapses and sensory hair cells, changes in protein levels in hair cells and supporting cells, hair cell regeneration, and determination of report gene expression (i.e., GFP) for verification of successful transduction and identification of transduced cell types. The cochlea, a bony spiral-shaped structure in the inner ear, holds the auditory sensory end organ, the organ of Corti (OC). Sensory hair cells and surrounding supporting cells in the OC are contained in the cochlear duct and rest on the basilar membrane, organized in a tonotopic fashion with high-frequency detection occurring in the base and low-frequency in the apex. With the availability of molecular and genetic information and the ability to manipulate genes by knockout and knock-in techniques, mice have been widely used in biological research, including in hearing science. However, the adult mouse cochlea is miniscule, and the cochlear epithelium is encapsulated in a bony labyrinth, making microdissection difficult. Although dissection techniques have been developed and used in many laboratories, this modified microdissection method using cell and tissue adhesive is easier and more convenient. It can be used in all types of adult mouse cochleae following decalcification.

Bilateral Vestibulopathy Due to Severe Cochlear Otosclerosis: A Well-Known Condition Without Any Favorable Solution

Bilateral vestibulopathy is a rare condition. It is one of the most difficult balance problems to treat because nearly all patients experience long-term unsteadiness. In this report, a 39-year-old woman gradually developing chronic dizziness and instability due to bilateral vestibulopathy as a result of progressive severe cochlear otosclerosis was presented with review of the literature.

Endoscopic approach for cochlear implantation in advanced otosclerosis: A case report

HYPOTHESIS

Ossification of the cochlea was once considered to be a contraindication for cochlear implantation. Advances in cochlear implant technology and coding strategies have led to developments in different surgical procedures to manage cochlear ossification. The endoscopic technique allows a direct approach to the round window and the cochlea, especially in remodeled labyrinth, allowing a better vision of scala tympani.

BACKGROUND

Tertiary referral ENT center.

METHODS

Between January 2011 and February 2015 three patients with far advanced otosclerosis with partial obliteration of the cochlea were selected and underwent endoscopic-assisted cochlear implantation.

RESULTS

In far advanced otosclerosis, endoscopy allowed a magnification of the anatomy of the round window, permitting the surrounding anatomical structures forming the anatomy of the niche to be identified, and avoiding a blind dissection. No postoperative complications were noted, in particular, no surgical site infection, no vertigo, and no facial nerve injuries. Implant activation was routinely performed 1 month after surgery. All monitoring till date has indicated that the external auditory ducts are well ventilated and there are no signs of extrusion.

CONCLUSIONS

Ossification may occur as a consequence of the pathology of meningitis, chronic otitis media, severe otosclerosis, autoimmune inner ear diseases, temporal bone traumas, and other diseases. Advances in cochlear implant technology and coding strategies have led to developments in different surgical procedures to manage cochlear ossification. Supported by a number of years of experience in the field of otoendoscopic surgery, we propose a technique for cochlear implantation under unfavorable conditions using endoscopic-assisted surgery, especially in advanced otosclerosis. This technique permits us to extend the indication for cochlear implantation, and in our opinion will reduce the morbidity associated with this surgical procedure.

Cochlear Implantation in Otosclerosis

OBJECTIVE

The purpose of this study was to evaluate and compare the results obtained in a group of implanted otosclerotic patients with a group of cochlear implant (CI) patients not affected by otosclerosis.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Nine patients affected by profound sensorineural hearing loss caused by otosclerosis and nine patients affected by profound sensorineural hearing loss not caused by otosclerosis were evaluated.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURES

Preoperative imaging, intraoperative findings, postoperative facial nerve stimulation, and speech perception performance measures were performed and the data analyzed.

RESULTS

Otosclerosis patients showed signs of cochlear ossification both on high-resolution computed tomography scans and intraoperatively. The incidence of facial nerve stimulation was higher in the otosclerosis group, three out of nine, and was generally related to the use of electrical stimulation from the Nucleus 22 cochlear implant. Psychophysical and speech perception measures did not show significant differences between the two groups, despite some otosclerosis patients showing increased electrical thresholds and comfort levels and slightly poorer speech perception performance scores.

CONCLUSIONS

Patients with otosclerosis who have progressed to profound hearing loss derive significant benefit from cochlear implants; however, an increased risk of cochlear ossification and facial nerve stimulation has to be taken in account during preoperative counseling. The advance in imaging techniques, CI technology and the possibility to stimulate precise regions of the cochlea with lower intensities make it possible for the surgeons and audiologists to readily and successfully manage these complications as they arise.

Spiral ligament and stria vascularis changes in cochlear otosclerosis: effect on hearing level

OBJECTIVE

To investigate the effect of changes within the spiral ligament and stria vascularis on hearing in cochlear otosclerosis, we examined spiral ligament hyalinization, stria vascularis atrophy, and sensory hearing loss in cochlear otosclerosis and described changes in ion transport molecule expression.

STUDY DESIGN

Retrospective.

SETTING

Tertiary referral center.

PATIENTS

Thirty-two cochleae from 24 temporal bone donors with histologic evidence of cochlear otosclerosis, including spiral ligament hyalinization.

INTERVENTION

Audiography.

MAIN OUTCOME MEASURES

Measurements of spiral ligament width, stria vascularis, and bone-conduction thresholds were compared by the amount of hyalinization. Expression of the ion transport molecules Na,K-ATPase, connexin 26, and carbonic anhydrase II were assessed by immunohistochemical techniques.

RESULTS

Hyalinization most often involved the posterior basal turn (88%) and the posterior middle turn (27%). Spiral ligament hyalinization correlated significantly with stria vascularis atrophy in the posterior middle turn of the cochlea (rho = -0.63, p < 0.01). There was a trend toward a significant association in the posterior basal turn (rho = -0.31, p < 0.08). Bone-conduction thresholds at 2,000 and 4,000 Hz were significantly associated with the amount of stria vascularis atrophy (rho = -0.44, -0.40, p < 0.05). In addition, we observed decreased immunostaining for both carbonic anhydrase II with Type I fibrocytes and Na,K-ATPase with stria vascularis and Type II and Type IV fibrocytes of the spiral ligament in cochlear otosclerosis sections compared with normal cochlea. Na,K-ATPase staining within the stria vascularis was further decreased in the presence of spiral ligament hyalinization. No significant differences were seen with connexin 26 immunostaining. However, immunostaining results were somewhat inconsistent.

CONCLUSION

These data suggest that spiral ligament structure and function are essential for stria vascularis survival. In addition, dampened expression of ion transport molecules within the spiral ligament and stria vascularis may disrupt potassium ion recycling, resulting in loss of endocochlear potential and sensory hearing loss.

Antigen retrieval immunohistochemistry used for routinely processed celloidin-embedded human temporal bone sections: standardization and development

The use of immunohistochemistry (IHC) in routinely processed celloidin-embedded human temporal bone section has created a fruitful field in understanding the pathogenesis and pathophysiology of the human inner ear at a molecular level since the early 1990s when the antigen retrieval (AR) technique was developed. This review article focuses on several critical technical issues of AR technique based predominantly on our experiences and suggestions concerning further development and standardization of AR-IHC for IHC study of human temporal bone section, as well as other tissues embedded in celloidin. Examples of using AR-IHC in human temporal bone sections collected include our unpublished data in order to indicate the potential utility of this novel method. Suggestions of further development of AR techniques are proposed for references and comments.

Etidronate for the Neurotologic Symptoms of Otosclerosis: Preliminary Study

The efficacy of etidronate, a Bisphosphonate, was assessed as a treatment for the inner ear symptoms of otosclerosis in a retrospective case review of 896 patients diagnosed with otosclerosis, with primary complaints of dizziness, hearing loss, tinnitus or Meniere's syndrome. The diagnosis of otosclerosis was based on small-pixel computed tomography of the temporal bones. Of the 896 patients placed on an etidronate protocol, 545 were followed for more than six months and were analyzed. The symptomatic response to etidronate, as well as audiologic and computerized rotary chair results were used in the assessment. Patients who were previously on sodium fluoride were separately analyzed. In this preliminary study etidronate appeared to be an effective treatment for the neurotologic symptoms of otosclerosis. Prospective blinded efficacy studies of the bisphosphonates in the treatment of otosclerosis should be undertaken.

Meniere's Syndrome: An Approach to Therapy

There are patients with symptoms similar to those of Meniere's disease who do not have Meniere's disease and therefore do not respond to conventional medical or conservative surgical management. Some have subtle disorders of carbohydrate and lipid metabolism and inner ear otosclerosis, which are responsible for the production of their symptoms. The response to dietary therapy confirms that glucose tolerance levels which are not diabetic nor hypoglycemic may be sufficiently significant in relation to inner ear function to produce the symptoms like those of Meniere's Disease. Management of inner ear otosclerosis with supplemental sodium fluoride, calcium carbonate, and Vitamin D was also effective in controlling the symptoms in some patients.

Cochlear vascular pathology and hydrops in otosclerosis

Three ears with otosclerosis were found incidentally in a series of human temporal bones examined to evaluate cochlear sensorineural degeneration. Otosclerosis was identified with microdissection, surface preparation technique and transmission electron microscopy. Vascular abnormalities were present in all ears, and otosclerosis involved the cochlear endosteum extensively, mainly in the scala tympani of the basal turn. In the scala tympani of the lower half of the basal turn, shunts had formed so that venules deviated abruptly from their normal radiating course towards the spiral vein, left the scala and entered into otosclerotic foci. There was a marked loss of radiating venules in areas where otosclerosis affected the endosteum of the scala. In the pair of bones capillaries in the stria vascularis were extremely dilated, the widest being 80 microns in diameter. The third single bone from a patient with Meniere's disease had severe cochleo-saccular hydrops. Ten serially sectioned temporal bones with known otosclerosis were reviewed. Two of the bones, one of which had cochleo-saccular hydrops, displayed vascular shunts in the scala tympani and enormously dilated strial capillaries with a maximum diameter of 139 microns.

Otosclerosis involving the vestibular aqueduct and Menière's disease

The coexistence of otosclerosis and endolymphatic hydrops in the temporal bone have been described; however, the mechanism for the development of endolymphatic hydrops in otosclerosis remains unknown. Among 128 temporal bones with otosclerosis, involvement of the vestibular aqueduct by otosclerosis was observed in four temporal bones from two patients. In all four, the vestibular aqueduct was filled with active otosclerotic foci; the lumen of the endolymphatic duct and sac was narrowed as a result of fibrosis, and endolymphatic hydrops, more severe in the pars inferior than the pars superior, was observed. Collapse of the ductus reuniens and dilated saccule was seen in three temporal bones. Our study indicates that otosclerotic obstruction of the vestibular aqueduct may create a disturbance of the outflow and/or absorption of endolymph, leading to the development of endolymphatic hydrops and Meniere's disease, thus supporting the theory of longitudinal flow of endolymph.

Correlation of otosclerotic foci and degenerative changes in the organ of Corti and spiral ganglion

Statistical analyses of histopathologic findings in the cochlea and spiral ganglion of 37 temporal bones with otosclerosis, 12 controls of similar age, and seven controls with normal hearing were performed. In temporal bones with otosclerosis there was significant atrophy of the spiral ligament and stria vascularis in regions with endosteal involvement by otosclerosis, compared with regions without endosteal involvement (P less than .0001). There was more generalized atrophy of the stria vascularis in cochleae with two or more sites of endosteal involvement by otosclerosis than in cochleae with only one site of endosteal involvement (P less than .02), cochleae in temporal bones with otosclerosis but without endosteal involvement (P less than .05), or cochleae of controls of similar age (P less than .007). In addition, there was more atrophy of the spiral ligament in cochleae with two or more sites of endosteal involvement than in cochleae of similar age from the control group (P less than .03). In temporal bones with otosclerosis, there was no significant difference in counts of outer hair cells and density of spiral ganglion cells between regions demonstrating endosteal involvement by otosclerosis and regions without such involvement. However, total outer hair cell counts were lower in cochleae with two or more sites of endosteal involvement of otosclerosis than in cochleae with one site of endosteal involvement (P less than .04), cochleae in temporal bones with otosclerosis but without endosteal involvement (P less than .02), or cochleae from individuals of similar age but without otosclerosis (P = .05). Comparison of the mean bone conduction threshold, as measured in life, in temporal bones with otosclerosis compared with the air conduction threshold in aged-matched controls, demonstrated that only cochleae with two or more sites of endosteal involvement had a mild but statistically significant (P = .05) decrease in hearing. There was no evidence to support the concept that otosclerotic foci without stapedial fixation frequently cause significant degeneration of the cochlea or elevation of bone conduction thresholds.

An abnormality in the human cochlear vasculature in a case of cis-platinum ototoxicity

The histopathological findings of a study of a human temporal bone are reported. The subject of this study was treated with cis-platinum in combination with bleomycin. High-frequency audiometry was performed pre- and post treatment. Microdissection for surface preparation was carried out after death. An unusual blood vessel in the cochlea was found. The possible cause of this vascular abnormality in the human cochlea is discussed.

Vitamin D deficiency and otosclerosis

A prospective study of 47 patients with otosclerosis was undertaken to investigate the possible etiologic role of vitamin D undernutrition. The population comprised 27 women and 20 men, with a mean age of 46.4 years (range 21 to 79). The disease was bilateral in 43 patients, and cochlear involvement was present in 84.4%. The mean duration of symptoms was 17.1 years. Vitamin D status was evaluated by measuring the plasma 25-hydroxy vitamin D3 (25-OHD), which is the main storage metabolite. Abnormally low 25-OHD levels were found in 10 patients (21.7%) and borderline low levels in another two. Raised serum alkaline phosphatase levels were present in 32.6%, calcium in 6.5%, and inorganic phosphate in 4.3%. Calcium and vitamin D replacement therapy resulted in significant hearing improvement in 3 of 16 patients; these data support a causal correlation. Vitamin D deficiency is probably a factor in the etiology of some cases of otosclerosis and is important, since the deafness resulting from cochlear involvement may be reversible.

Microscopic characteristics of round window problems in otology

Round window membrane ruptures and perilymph leakage can present the complication or concomitant of sudden deafness and barotrauma. Pathological involvement of the round window membrane can occur in many otological diseases such as otosclerosis, otitis media, tumors, etc. Microscopic manipulations might result in an inadvertent round window membrane lesion and cochlear deafness. In recent years purposeful surgical lesions, including procedures for vertigo and cochlear implant surgery, are being made in the round window membrane. Examples of pathology involving the round window in human temporal bones are described. To understand better the clinical features of early round window rupture in humans,, controlled punctuate lesions were made in 36 chinchilla ears and studied sequentially. Round window membrane healing occurred as early as 3 days post-lesion, and was complete in all ears but 1 of the combined 7, 9 and 11-day group. Healing occurred primarily as a result of middle ear epithelial ingrowth and mesothelial cell reaction in the adjacent perilymphatic space of the scala tympani. These cellular events are described and discussed from an histological and clinical point of view.

The round window membrane: otological observations

The membrane of the round window serves as a barrier between the middle and inner ear and has a well-established role in cochlear physiology. It is important in many otological conditions: otitis media, otosclerosis, trauma, sequelae to drugs reaching the middle ear, tumors, congenital dysplasia, sudden deafness. We here describe the first electron microscopic findings in round window membranes from adult humans, and various conditions in reference to these findings. Since surgical lesions are made in this membrane during cochlear implantation, and by some otologists in treating vertigo, preliminary findings of a lesioning experiment in animals are presented. Interestingly, early healing resulted from a mesothelial cellular reaction in the adjacent scala tympani, with formation of clots, while in the middle ear the epithelial cellular layer sealed the edges of the perforation, leading to formation of an indentation ("pocket"). Subsequently, the middle layer of the membrane contributed to healing.

Utricular and saccular volumetry in human temporal bones

Using serially sectioned human temporal bones, endolymphatic volumes of utriculus and sacculus were measured with the aid of a computer. The mean of the utricular volume was 8.187 mm3, and the saccular volume, 2.096 mm3. The former was 3.9 X the latter. The surface area of the macula utriculi was 3.271 mm2, and the macula sacculi was 2.188 mm2. The former was 1.5 X the latter. The study using pathologic temporal bones (Meniere's disease, otosclerosis, and otitis media chronica) showed that the utricular volume could indeed increase, and the saccular membrane was found to be more fragile than the utricular membrane in those diseased conditions.

Fluctuating hearing loss and recurrent vertigo in otosclerosis. An audiologic and temporal bone study

This report summarizes audiologic and temporal bone findings in a 47-year-old white female with recurrent attacks of vertigo, tinnitus, and bilateral hearing loss. A series of audiograms, obtained over a 15-year period, showed a fluctuating mixed (sensorineural and conductive) hearing loss with a relatively flat configuration in the left ear and a relatively stable, mild sensorineural loss with a sloping contour in the right ear. Temporal bone studies revealed the existence of otosclerotic foci bilaterally. In the left ear, the otosclerotic focus has grown close to the utricular and lateral ampullary nerves, displaced and ankylosed the stapedial footplate, invaded the endosteal zone (1,000-2,000 Hz area), and deformed the lateral cochlear wall. In the right ear, the otosclerotic invasion was limited to the inferior portion on the promontory (vestibular cecum) and round window niche.

Otosclerotic involvement of the cochlea: a histologic and audiologic study

This study sought correlations between sensorineural hearing loss and otosclerotic endosteal involvement in 29 temporal bones examined histologically. The sensorineural hearing loss of the affected parts of the cochlea was determined by the last antemortum bone conduction audiogram available. There were eight temporal bones with only stapes footplate involvement, six with one discrete focus of otosclerotic endosteal involvement, and 15 with two or more foci of endosteal involvement. Analysis of audiometric data showed that the group of bones with two or more foci of endosteal involvement had a similar incidence of 45 dB sensorineural loss (9 of 15 or 60%) as did the group with no endosteal involvement (5 of 8 or 62%). The group with two or more foci had a greater incidence of 60 dB or greater sensorineural loss (46%) compared with the groups with none (12%) or one focus (16%) involved. Correlation between hearing loss and involvement of cochlear endosteum was poor. Correlation existed in only 2 of 15 ears with two or more foci involving the cochlear endosteum. There was no correlation in the other groups. It appears that cochlear endosteal involvement alone may not be sufficient explanation for the sensorineural hearing loss found with otosclerosis, except in the most severely involved ears.

Progressive sensorineural hearing loss and cochlear otosclerosis: a prospective study

The association of otosclerosis with reduced bone conduction is well known but no experimental or valid clinical relationship has been established to confirm this relationship. The purpose of this presentation is to demonstrate a clinical relationship between otosclerosis and sensorineural hearing loss. Experimental proof will await the accumulation and study of temporal bones of those individuals who, in life, exhibited the clinical relationship to be developed in this dissertation.