Tympanometric measurements in conscious sheep - a diagnostic tool for pre-clinical middle ear implant studies

Pohl, Friederike; Paasche, Gerrit; Lenarz, Thomas; Schuon, Robert

doi:10.1080/14992027.2016.1227480

Cited by 4 publications

(6 citation statements)

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“…Due to species restraints regarding the frequency of anesthesia (limited to once a week), the follow up was performed on day seven after the instillation of PAF and prostaglandin E 2 . Unfortunately, use of the tympanometry method in sheep [ 28 ] was not available at the time the examination was performed, which would have facilitated monitoring of middle ear effusion or negative middle ear pressure [ 3 ] at shorter intervals. Therefore, we can only speculate about the reasons for missing inflammatory signs related to the application of the substances.…”

Section: Discussionmentioning

confidence: 99%

Stenting the Eustachian tube to treat chronic otitis media - a feasibility study in sheep

et al. 2018

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BackgroundUntreated chronic otitis media severely impairs quality of life in affected individuals. Local destruction of the middle ear and subsequent loss of hearing are common sequelae, and currently available treatments provide limited relief. Therefore, the objectives of this study were to evaluate the feasibility of the insertion of a coronary stent from the nasopharynx into the Eustachian tube in-vivo in sheep and to make an initial assessment of its positional stability, tolerance by the animal, and possible tissue reactions.MethodsBilateral implantation of bare metal cobalt-chrome coronary stents of two sizes was performed endoscopically in three healthy blackface sheep using a nasopharyngeal approach. The postoperative observation period was three months.ResultsStent implantation into the Eustachian tube was feasible with no intra- or post-operative complications. Health status of the sheep was unaffected. All stents preserved their cylindrical shape. All shorter stents remained in position and ventilated the middle ear even when partially filled with secretion or tissue. One of the long stents became dislocated toward the nasopharynx. Both of the others remained fixed at the isthmus but appeared to be blocked by tissue or secretion. Tissue overgrowth on top of the struts of all stents resulted in closure of the tissue-lumen interface.ConclusionStenting of the Eustachian tube was successfully transferred from cadaver studies to an in-vivo application without complications. The stent was well tolerated, the middle ears were ventilated, and clearance of the auditory tube appeared possible. For fixation, it seems to be sufficient to place it only in the cartilaginous part of the Eustachian tube.Electronic supplementary materialThe online version of this article (10.1186/s13005-018-0165-5) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Stenting the Eustachian tube to treat chronic otitis media - a feasibility study in sheep

et al. 2018

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“…Tympanometry is a suitable means of measuring the course of pressure in the middle ear of the sheep [ 27 ]. In the current study, a negative pressure in the middle ear could be measured first, starting shortly after the injection of HA and followed by a non-vibrating tympanic membrane (curve type B), which indicated a tympanic effusion.…”

Section: Discussionmentioning

confidence: 99%

“…One week before the HA injection was performed, the EAC was cleaned mechanically under general anesthesia (GA) following the protocols of Pohl et al 2017 [ 27 ].…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…To determine the middle ear pressure, tympanometric measurements were performed on conscious sheep with a commercial handheld tympanometer (Madsen Otoflex 100, GN Otometrics, Münster, Germany) using the method of Pohl et al 2017 [ 27 ]. A special adapter [ 27 ] was used due to the longer EAC in sheep compared to humans. It consisted of a polyurethane tube (PUN-6 × 1, Festo AG & Co KG, Esslingen, Germany) attached to a connecting piece of a KimVent Microcuff Endotracheal Tube (Kimberley-Clark, Roswell, NM, USA).…”

Section: Methodsmentioning

confidence: 99%

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Development of an In Vivo Model for Eustachian Tube Dysfunction

Oppel

Ezzat

Krüger³

et al. 2022

Bioengineering

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Otitis media is often connected to Eustachian tube dysfunction (ETD). Until now, there was no large animal model available for the examination of new treatment methods such as stents for the Eustachian tube (ET). Thus, the aim of the study was to develop a method to reproducibly induce ETD by injection of fillers and without permanent closure of the ET. Tools for safe injection of hyaluronic acid (HA) in the surrounding of the ET were developed. In ex vivo experiments, HA mixed with Imeron® was injected close to the nasopharyngeal orifice of the ET of blackface sheep. The established depot was visualized using cone beam computer tomography and magnetic resonance imaging, and stents could be placed into the ET. A reliable position of the HA depot was achieved. This method was transferred to in vivo, and middle ear ventilation was investigated by tympanometry. ETD was achieved with amounts of 2.5 mL HA or higher. None of the animals showed any sign of discomfort or complications. The induced ETD lasted for 3 to 13 (maximum observation period) weeks and was also combined with middle ear effusion. A model of ETD based on injection of HA next to the ET was successfully established and is now available to test novel treatment options for ET functionality.

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Hearing loss in patients with scleroderma: associations with clinical manifestations and capillaroscopy

et al. 2018

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Systemic sclerosis is a multi-systemic disease with widespread small-vessel vasculopathy and fibrosis. Involvement of the middle and inner ear and hearing loss has been reported as an uncommon manifestation of scleroderma in some studies. In this study, we evaluated hearing problems in scleroderma patients and determined its association with clinical manifestations and capillaroscopy. We evaluated 54 patients with scleroderma referred to Hafez Hospital clinic of scleroderma related to Shiraz University of Medical Science; they fulfilled the LeRoy and ACR/EULAR criteria for scleroderma. Control group consisted of 60 normal individuals. All clinical manifestations, nail fold capillaroscopy, pure tone audiometry, speech reception threshold, and speech audiometry were recorded during evaluation. Subjective hearing loss and objective hearing loss were seen in 10 and 36 patients of the case group (18.5%, 66.7%) and 6 and 10 of the control group (10%, 28.3%) (P values 0.03, < 0.001). Sensorineural hearing loss, abnormal pure tone audiometry, and abnormal speech reception threshold were more common in scleroderma patients compared to the control group (P values of < 0.001, < 0.001, and < 0.001). There was no correlation between objective hearing loss and type of scleroderma, duration of disease, skin score, interstitial lung disease, digital ulcer, gastrointestinal involvement, or nail fold capillaroscopy patterns (all P values > 0.05). In our study, subjective and objective hearing loss were higher in patients with scleroderma compared to the control group and also sensorineural hearing loss, abnormal pure tone audiometry, and abnormal speech reception threshold. There was no correlation between objective hearing loss and clinical manifestations or capillaroscopy findings.

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Tympanometric measurements in conscious sheep - a diagnostic tool for pre-clinical middle ear implant studies

Abstract: The current study demonstrated how tympanometry can be used to evaluate treatment modalities for middle ear and ET function in conscious sheep. This provided a large animal model for further human research in otology.

Cited by 4 publications

References 23 publications

Stenting the Eustachian tube to treat chronic otitis media - a feasibility study in sheep

Stenting the Eustachian tube to treat chronic otitis media - a feasibility study in sheep

Development of an In Vivo Model for Eustachian Tube Dysfunction

Hearing loss in patients with scleroderma: associations with clinical manifestations and capillaroscopy

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