UC Expands Middle Ear Research

Researchers and students are expanding on a breakthrough study which was conducted at UC.

Date: February 22, 2012
By: Kelley Ujvary

It started with research conducted at UC by Dr. Ravi Samy, Assistant Professor of Otolaryngology Pediatric and Adult Otology/Neurotology, and continued last year with a CEAS Senior Design Project. 

Mechanical Engineering students Brian Kim, Brian Kunes, Matt Schnuth and Andy Ward took work done by Dr. Samy on the middle ear to create a prototype of this very tiny section of the inner ear, something that had not been done before.   

According to the student’s research report, the purpose of the research was to “determine the properties and behavior of the different components and tissues of the middle ear ossicular chain.”  From here, the team could learn the inner workings of the ear, and create a prototype that researchers, med school students and doctors all over the world can use to enhance their knowledge and capabilities of working with the middle ear.

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Top: A 3D rendering of the three bones in the middle ear that students used as a guide when building their prototype. Bottom: Creation of the prototype: It was held model in place and joint capsule were made with modeling clay. The team then filled the capsule with 30A RTV Urethane rubber to act as the tissue between the joint.

The middle ear consists of three bones suspended in the tympanic cavity of the ear and held in place by muscle and tendons.  To provide the best mental image of the size of these three bones (the malleus, incus, and the stapes), Dr. Vasile Nistor, Assistant Professor in Biomedical Engineering, describes them as being “so small they could fit inside a pea.”  The function and importance of your middle ear is to send vibratory signals to the cochlea, which then generates an electric signal and sends it to the brain. 

We have all experienced pain from the ear that you cannot control and most people just assume that it is nothing and wait for it to go away.  Dr. Dan Humpert, Associate Professor of Mechanical Engineering, says that too often, ear infections go undetected for years, and by the time they are recognized it can be too late;  the bacteria has deteriorated the bones of the middle ear. 

Aside from ear infections, there are accidents that can happen that can dislocate the bones of the middle ear including near explosions and yes, arthritis of the ear. 

In a high risk ossiculoplasty, surgery can be done to repair the middle ear bones after they have been weakened. Surgeons drill the temporal bone behind your ear, moving past the brain and into the middle ear, while along the way passing very large arteries.    

The students, under the guidance of Dr. Nistor and Dr. Humpert, developed a prototype of the middle ear and are on the path to inner ear repair.  The school of Energy, Environmental, Biological and Medical Engineering (SEEBME) has coined this prototype with the hopes of better understanding the middle ears inner workings and how we can repair it in the safest way. 

Kunes told us that “One struggle of the project was finding industrial and synthetic materials that mimic the material and mechanical properties of the living tissue and bone.”

The team ran a range of tests on the prototype to study how the bones react to certain stimuli, such as vibrations, and what affects these bones. 

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The final product: The three bone prototype of the middle ear suspended inside a Plexiglas box which acts as the tympanic cavity. The red rubber bands represent muscles and tendons.

“The importance of this project,” Ward told us, “was to find the transfer function between the outer ear and the inner ear; how the middle ear ossicular mechanism changes the sound that comes in the ear before going into the cochlea. Our project served more as a basis for a project that could be repeated in the future with enhanced materials with more anatomic characteristics.”

The prototype is now being used by a graduate student who is refining the model and making sure it is ready for the next step, enlarging the prototype 20x for training and educational purposes.

In addition to this research that focused on improving inner ear repair, there is another goal the researchers have for their study of the inner ear.  The robotics lab in CEAS, under the direction of Dr. Humpert, is also working on developing a replacement; a robotic ear that will function as normal as a human ear when the middle ear has been damaged beyond repair.  Inserting this device will include a placement procedure that minimizes the risk of getting in close contact with the brain and the arteries around the brain and ear. 

Since this project requires medical device and mechanical building experience, Dr. Nistor who is from SEEBME and Dr. Humpert from Mechanical Engineering teamed up to collaborate on this project.  “The robotics lab has a knowledge base to work on areas that need their skills,” said Dr. Nistor.

After the 20x prototype has been developed and their research has been printed in scientific publications, the research teams expect that in 2-3 years the robotic ear will be developed and be in the testing phase.  With such a big future for this research, Dr. Nistor foresees many opportunities and great involvement for students working on senior design projects and gaining first hand research experience. 

Since the bones and the inner workings of the ear are so intricate, the process to repair them has been nearly impossible to master.  Thanks to developed research at UC, the medical community is one step closer to solving hearing loss and creating new options for patients. 

View their story in UCResearch.