A single dose of dexamethasone encapsulated in polyethylene glycol-coated polylactic acid nanoparticles attenuates cisplatin-induced hearing loss following round window membrane administration

Objective: To investigate the effects of the mechanical trauma to the round window, a model electrode inserted into the scala tympani on the cochlear reserve, and the efficacy of topical steroids in preventing hearing loss. Materials and Methods: 21 male Wistar Albino rats were equally categorized into three groups. In all groups an initial mechanical injury to round window was created. Only subsequent dexamethasone injection was administrated into the cochlea in the subjects of group 2 while a multichannel cochlear implant guide inserted into the cochlea prior to dexamethasone administration for group 3. Distortion product otoacoustic emissions (DPOAEs) were obtained prior to and immediately after the surgical injury, eventually on postoperative seventh day (d 7). Mean signal/noise ratios (S/Ns) obtained at 2000, 3000, and 4000 Hz were calculated. Data sets were compared with non-parametric statistical tests. Results: The early intraoperative mean S/Ns were significantly less than preoperative measurements for group 1 and 2; however, preoperative and postoperative d 7 average S/Ns did not differ. There was statistically significant difference between preoperative, intraoperative and postoperative d 7 average S/Ns for group 3. Conclusion: We observed that hearing was restored approximately to the preoperative levels following early postoperative repair. However, an electrode insertion into the cochlea via round window subsequent to mechanical trauma seems to cause a progressive hearing loss. Therefore, a special care must be taken to avoid the injury to the round window membrane in the course of the placement of a cochlear implant electrode and surgery for the chronic otitis media.

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Cochlear Implantation Following Explorative Tympanotomy in Patients With Sudden Sensorineural Hearing Loss: Surgical Features and Audiological Outcomes

Ear Nose & Throat Journal ◽

10.1177/01455613211009141 ◽

2021 ◽

pp. 014556132110091

Author(s):

Robin Rupp ◽

Joachim Hornung ◽

Matthias Balk ◽

Matti Sievert ◽

Sarina Müller ◽

...

Keyword(s):

Hearing Loss ◽

Connective Tissue ◽

Sensorineural Hearing Loss ◽

Cochlear Implantation ◽

Round Window ◽

Sudden Sensorineural Hearing Loss ◽

Sensorineural Hearing ◽

Round Window Membrane ◽

Hearing Results ◽

Round Window Niche

Objective: To investigate the anatomical status of the round window niche and hearing outcome of cochlear implantation (CI) after explorative tympanotomy (ExT) with sealing of the round window membrane in patients with sudden sensorineural hearing loss at a tertiary referral medical center. Methods: Between January 1, 2007, and July 30, 2020, 1602 patients underwent CI at our department. Out of these, all patients previously treated by ExT with sealing of the round window membrane because of unilateral sudden hearing loss were included in the study. A retrospective chart review was conducted concerning method of round window membrane sealing, intraoperative findings during CI, postoperative imaging, and hearing results. Results: Twenty one patients (9 females; 8 right ears; 54.3 years [± 12.9 years]) underwent ExT with sealing of the round window membrane with subsequent CI after 26.6 months (± 32.9 mo) on average. During CI, in 76% of cases (n = 16), the round window niche was blocked by connective tissue due to the previous intervention but could be removed completely in all cases. The connective tissue itself and its removal had no detrimental effects on the round window membrane. Postoperative computed tomography scan showed no electrode dislocation. Mean postoperative word recognition score after 3 months was 57.4% (± 17.2%) and improved significantly to 73.1% (± 16.4%, P = .005) after 2 years. Conclusion: Performing CI after preceding ExT, connective tissue has to be expected blocking the round window niche. Remaining tissue can be removed safely and does not alter the round window membrane allowing for a proper electrode insertion. Short- and long-term hearing results are satisfactory. Consequently, ExT with sealing of the round window membrane in patients with sudden sensorineural hearing loss does not impede subsequent CI that can still be performed safely.

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Direct drug application to the round window: A comparative study of ototoxicity in rats

Otolaryngology ◽

10.1016/j.otohns.2009.07.014 ◽

2009 ◽

Vol 141 (5) ◽

pp. 584-590 ◽

Cited By ~ 10

Author(s):

Silvia Murillo-Cuesta ◽

Fernando García-Alcántara ◽

Elena Vacas ◽

Jon Alexander Sistiaga ◽

Guadalupe Camarero ◽

...

Keyword(s):

Hearing Loss ◽

Cell Damage ◽

Round Window ◽

Drug Application ◽

Local Drug Delivery ◽

Saline Control ◽

Round Window Membrane ◽

Cochlear Function ◽

Profound Hearing Loss ◽

Brainstem Response

Objective: To assess the validity of inducing ototoxicity in rats by applying a sponge soaked in kanamycin and furosemide on the round window. Study Design: Basic, randomized, nonblind experimental study. Setting: Animal models of cochlear damage and reliable methods of local drug delivery are fundamental to study hearing loss and to design new therapies. Subjects and Methods: Four experimental groups of six Wistar rats with different methods of drug administration were used: (1) injection of subcutaneous kanamycin (400 mg/kg) and intravenous furosemide (100 mg/kg); (2) local application of a sponge soaked in saline close to the round window; (3) animals for which the sponge was soaked in a solution containing kanamycin (200 mg/mL) and furosemide (50 mg/mL); and (4) sham-operated rats. The tympanic bulla was exposed using a ventral approach, and a bullostomy was performed to visualize the round window membrane. Cochlear function was assessed by measuring the auditory brainstem response, and hearing thresholds in response to click and tone burst stimuli were determined as peak and interpeak latencies. At the end of the study, cochlear histology was analyzed. Results: Systemic administration of kanamycin and furosemide induced profound hearing loss and severe hair cell damage. Local delivery of these ototoxic drugs caused comparable damage but avoided the systemic side effects of the drug. Sham-operated and saline control animals did not experience functional alterations. Conclusion: Situating a sponge soaked in kanamycin and furosemide on the round window membrane through the ventral approach is a reliable method to provoke local ototoxicity in rats.

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Analysis of 60 patients after tympanotomy and sealing of the round window membrane after acute unilateral sensorineural hearing loss

American Journal of Otolaryngology ◽

10.1016/j.amjoto.2009.06.007 ◽

2011 ◽

Vol 32 (1) ◽

pp. 88-89 ◽

Cited By ~ 2

Author(s):

Dong-Hee Lee

Keyword(s):

Hearing Loss ◽

Sensorineural Hearing Loss ◽

Round Window ◽

Sensorineural Hearing ◽

Round Window Membrane

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Preoperative Evaluation and Surgical Outcome of Cochlear Implantation in NIENT

Bangladesh Journal of Otorhinolaryngology ◽

10.3329/bjo.v26i2.50640 ◽

2020 ◽

Vol 26 (2) ◽

pp. 128-135

Author(s):

Md Zakaria Sarker ◽

Muhammad Rafiqul Islam ◽

Utpal Kumar Dutta ◽

Debabrota Roy ◽

AHM Ferdows Nur ◽

...

Keyword(s):

Hearing Loss ◽

Facial Nerve ◽

Psychosocial Development ◽

Cochlear Implantation ◽

Preoperative Evaluation ◽

Round Window ◽

Round Window Membrane ◽

Safe Procedure ◽

Female Ratio ◽

Facial Recess

Background: Sensory neural hearing loss (SNHL) is the most common congenital sensory deficit, with an incidence of one to three per 1000 live births. Acoustic deprivation during the first 3 years of life can hinder speech and language acquisition with significant negative consequences on a child’s educational and psychosocial development. The gold standard intervention for permanent severe to profound hearing loss is cochlear implantation. Cochlear implant (CI); is a semi implantable electronic device that bypass the cochlea. Objectives: An observational study was carried out on 40 cases of pre-lingual deaf to find out the causes of pre-lingual deaf, to evaluate the preoperative procedures to set ideal criteria for pre -lingual cochlear implantation and to evaluate surgical procedure and outcome of cochlear implantations. Methods: Evaluation of the candidates included patient medical history, general health checkup, ENT examination, audiometric evaluation, CT and MRI scans, psychological profile of the candidate. A limited cortical mastoidectomy was performed. The facial recess was opened using the fossa of incudis as an initial landmark. The round window niche was visualized through the facial recess about 2 mm inferior to the stapes. A cochleostomy created by drilling over the basal turn of the cochlea anterior and inferior to the annulus of the round window membrane. The electrode array was then carefully inserted through the fenestra into the scala tympani of the cochlea. Electrophysiological testing (Neural Response Telemetry: NRT) was performed to verify the correct placement of active electrodes. Resulst: Among them 22 (55%) were male and 18 (45%) were female. Male female ratio was 1.2:1. Age distribution at implantation was 3.3±1.054(SD). Average hearing loss was 96.4±5.3(SD) dB and in aided audiogram was 63.7±4.6(SD) dB. Overall complications occurred in 10 (25%) cases. Transient facial nerve paresis in 2 (5%), injury of tympanic membrane in 1(2.5%), seroma 4(10%) and delayed otitis media in 1(2.5%) were observed. Major postoperative complications occurred in 2 cases including facial nerve palsy in 1(2.5%) case and spontaneous device failure in 1(2.5%) case. Conclusion: The result of this survey was find out the risk factor of congenital hearing loss. With a thorough preoperative evaluation, we can select proper candidates for CI which is a reliable and safe procedure with a low percentage of severe complication. Bangladesh J Otorhinolaryngol; October 2020; 26(2): 128-135

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Efficiency of a Dexamethasone Nanosuspension as an Intratympanic Injection for Acute Hearing Loss

10.21203/rs.3.rs-915620/v1 ◽

2021 ◽

Author(s):

So-Young Jung ◽

Zion Kang ◽

Soonmin Kwon ◽

Juhye Lee ◽

Subin Kim ◽

...

Keyword(s):

Hearing Loss ◽

Inner Ear ◽

Round Window ◽

Round Window Membrane ◽

In Vivo Test ◽

Drug Concentrations ◽

Intratympanic Injection ◽

Acute Hearing Loss

Abstract Background: Dexamethasone sodium phosphate (Dex-SP) is the most commonly used drug for intratympanic injection in acute hearing loss, but its penetration efficiency into the inner ear is very low. To address this problem, we evaluated the possibility of dexamethasone nanosuspensions as intratympanic injection because the lipophilicity of drugs can affect their permeation of the round window membrane, an important pathway from the middle ear to the cochlea.Results: Three types of dexamethasone nanosuspensions were prepared; the dexamethasone nanocrystals in the three nanosuspensions were between approximately 250 and 350 nm in size. In order to compare the efficiency of Dex-SP and a dexamethasone nanosuspension in delivering dexamethasone to the inner ear, the concentrations of dexamethasone in perilymph and cochlear tissues were compared by liquid chromatography–mass spectrometry. The dexamethasone nanosuspensions showed significantly higher drug concentrations in perilymph and cochlear tissue than Dex-SP at 6 h; interestingly, animals treated with a nanosuspension showed a 26-fold higher dexamethasone concentration in the cochlear tissue than the Dex-SP group. In addition, the dexamethasone nanosuspension achieved better glucocorticoid receptor phosphorylation than Dex-SP both in vitro and in vivo, and in the ototoxic animal model, it showed a significantly better hearing protective effect than Dex-SP against ototoxic drugs. In safety evaluation, the nanosuspension showed no toxicity at concentrations up to 20 mg/mL in an in vivo test.Conclusions: A nanosuspension of dexamethasone was able to deliver dexamethasone to the cochlea very safely and efficiently and showed potential as a formula for intratympanic injection. In addition, it can be applied in studies on the delivery of various hydrophobic antioxidants to treat acute hearing loss.

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Effects of lonomer Cement on Guinea Pig Cochleas

Ear Nose & Throat Journal ◽

10.1177/014556139707600410 ◽

1997 ◽

Vol 76 (4) ◽

pp. 223-230 ◽

Cited By ~ 7

Author(s):

Taisuke Kobayashi ◽

Yasuyuki Hinohira ◽

Masamitsu Hyodo ◽

Goran Bredberg ◽

Edel Alsterborg

Keyword(s):

Hearing Loss ◽

Guinea Pig ◽

Guinea Pigs ◽

Morphological Study ◽

Round Window ◽

Cell Loss ◽

Round Window Membrane ◽

Hair Cell Loss ◽

Ear Surgery ◽

Hearing Thresholds

The inner ear toxicity of ionomeric cement (lonocem®) when used as a reconstructive material in ear surgery was evaluated in 47 guinea pigs used in a morphological study. The cement was implanted on either the promontory, the round window membrane or the stapes. There was no significant hair cell loss compared with the control ear at three weeks, two months or three months after implantation. Using electrocochleography, the hearing thresholds before, and three weeks, two and three months after the implantation were compared in an additional seven animals. No evident hearing loss was observed in any animal during the study period. No morphological or functional evidence for an ototoxic effect of the ionomeric cement was found in this study.

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