EYE & ENT HOSPITAL OF
Middle Ear Mechanics - Technology and Oto-surgery
Topics of MEMRO2018
1) Biomechanics of the Middle Ear
2) Middle Ear Physiology
3) Surgical Techniques & Reconstructions
4) Middle Ear Pathology and Diagnostics
5) Middle Ear Implants (Active and Passive)
6) Computational Models
7) Imaging Technologies
8) Bone Conduction (Basic science and Clinical application)
9) Evolution & Development
10）High Intensity Sound-Induced Hearing Damage and Protection
Alexander Huber, MD
Professor and Chair
Department of Otorhinolaryngology, Head and Neck Surgery
University Hospital Zurich
Biomechanics in Otology – The Clinician's View
It is the purpose of this lecture to discuss the clinical backgrounds of otological topics relevant to middle ear mechanics. The successful collaboration of engineers and clinicians led to better understanding of diseases, to new diagnostical means and to effective surgical therapies. These collaborations finally led to improved quality of life for many patients in the past. But there are still areas in otology where improvement is needed and this may be facilitated by such collaborations. Examples are reviewed. The lecture covers otologic disorders particularly related to otosclerosis, hearing loss due to chronic otitis media and reconstructive therapies involving implantable hearing aids.
Brian E. Applegate, PhD
Department of Biomedical Engineering
Texas A&M University
Subnanometer spatially resolved vibrometry of middle and inner ear with Optical Coherence Tomography and Vibrometry
Over the past eight years we have been developing Optical Coherence Tomography and Vibrometry (OCTV) to measure the detailed morphology and vibratory response of the ear. With micron scale spatial resolution and subnanometer sensitivity to vibration it is well suited to measuring the spatially resolved vibratory response of both the inner and middle ear. In small animals, it is possible to image directly through the bone of the otic capsule for noninvasive spatially resolved vibrometry of the cochlear partition. In humans as well as small animals, it’s possible to image the tympanic membrane and ossicles through the ear canal to reveal the vibratory response of the middle ear.
Sunil Puria, PhD
Eaton-Peabody Laboratory, Massachusetts Eye and Ear
Department of Otolaryngology
Harvard Medical School
The Growing Potential of Finite Element Modeling as an Investigative Tool in Middle-Ear Mechanics
Significant progress has been made since the development of the earliest middle-ear circuit models, which were primarily tested against impedance and one-dimensional vibration measurements. Modern high-resolution finite-element modeling incorporates realistic three-dimensional anatomy obtained from high-resolution imaging techniques (e.g., uCT and OCT), and provide a much tighter coupling between anatomical structure and function. Assuming appropriate choices of material properties and sufficient validation against real-world measurements, such models can be invaluable tools for conducting studies of the effects of structural variations within the middle ear, where they allow the functional effects of arbitrary structural and material variations to be studied in a well-controlled manner.
Not only can finite-element models coupled with high-resolution imaging be developed and used in the comparative study of living species, but one could also conceivably use evidence from the fossil record, combined with assumptions about soft-tissue attachments, to develop models of the reconstructed middle-ear structures of extinct species to compare their predicted capabilities against those of their present-day descendants. I will review some of these finite-element modeling techniques, their continued development, their application to middle-ear reconstruction and multiple use, diagnosis of disease, as well as their potential application to comparative studies in extant and extinct vertebrate species.
Abigail Tucker, PhD
Department of Craniofacial Development & Stem Cell Biology
King's College London
Development and repair of the murine ear-drum
The tympanic membrane, or ear drum, is composed of two parts, the pars tensa and pars flaccida. These two regions develop at different time points and have a unique embryonic make up, helping to explain their different structural properties. The tympanic membrane is very susceptible to damage caused by ear infections, pressure changes or head trauma. Most holes in the membrane heal rapidly without any intervention and it has been proposed that adult stem cells reside in the ear and are able to aid in regeneration and healing of holes. We show that the putative adult stem cell marker Sox2 is expressed in distinct parts of the ear-drum, at the border (the annulus) and in the centre, where the ear drum meets the middle ear bones (manubrium). These regions coincide with the presence of BrDU label retaining cells, a hallmark for adult stem cells. Lineage tracing of the Sox2 cells reveals a high turn over in the ear-drum with Sox2 progeny forming the entire inner endoderm layer of the drum. Signaling pathways involved in repair, such as Wnts, are also active in the regions that express Sox2. We have used a novel whole ear drum culture technique to follow the repair process in vitro in the mouse pars tensa, allowing us to track the contribution of putative stem cells and their progeny and to investigate the mechanisms involved in repair of this unusual structure. We find that Sox2 adult stem/progenitor cells and Wnt signaling play a crucial role in repair of the ear-drum.