July 28, 1997
Contact:
Leila Belkora
UIC Public Affairs
(312) 996-3457
[email protected]
A three-dimensional view of the fine bones, nerves, and hollow spaces in the human ear -- from any vantage point inside or outside the organ -- is now possible, thanks to a virtual model constructed by a team of researchers at the University of Illinois at Chicago.
The model, which viewers explore using a wand and a special pair of eyeglasses while facing a 20-square-foot screen called an ImmersaDesk, allows surgeons to familiarize themselves with the complex spatial relationships of structures composing the ear. It also offers students of all ages an unprecedented opportunity to "get inside" a hidden part of the body.
Visitors to the Virtual Reality in Medicine Laboratory in UIC's school of biomedical and health information sciences say the prototype virtual tour of the ear is particularly striking because they see a translucent pink eardrum vibrate and jostle the malleus bone in a real-time response to the viewer's speaking into a microphone.
Theodore Mason, M.D., a resident in UIC's department of otolaryngology-head and neck surgery who suggested the project to the biomedical visualization team, was motivated by the difficulty of learning surgery on the head and neck.
"The problem is there are very delicate structures -- nerves, hearing organs, structures for balance -- all of these things encased in bone as in a cue ball," says Mason. "To treat some disease processes we have to go in with a drill, without hitting anything; one false move and the patient could be deaf, or one side of their face be paralyzed. Surgeons in training spend untold hours studying the anatomy of this region."
Mason and otolaryngology department chairman Edward Applebaum, M.D., gave Mary Rasmussen and Alan Millman, co-directors of the Virtual Reality in Medicine Laboratory, a collection of more than 300 glass slides mounted with cross-sectional cuts through a human temporal bone and ear.
The sections form the basis of the model, but some of the bones in the ear are "so tiny," according to Rasmussen, that they were not preserved in the sections.
Mason, Rasmussen and Millman worked with medical illustrator Ray Evenhouse and physicians, art students specializing in sculpture and computing assistants to integrate the slides and sculpted models of the ossicles -- three small bones of the middle ear -- into an electronic three-dimensional model of the
temporal bone and ear. The result, they say, is a more complete and better representation of the complexity of the organ than any two-dimensional drawing or sculpted model.
"An ImmersaDesk is worth a thousand pictures," says Rasmussen.
Mason says exploring the ear with the ImmersaDesk won't replace the experience of drilling into the temporal bone to the middle ear; part of his training is to learn the feel of the instrument and to listen for the subtle change in sound as the bit approaches a sinus cavity or other structure. Surgeons in training typically operate on 20 to 30 cadaver bones before touching a real patient, he says. However, Mason says, the virtual reality ear provides valuable complementary training.
"When I'm drilling I can imagine the model," says Mason. "It's like working on a glass temporal bone. You have an idea what it's like from inside the brain."
The ImmersaDesk is a product of UIC's Electronic Visualization Laboratory in the College of Engineering. It's a scaled-down version of the CAVE (Cave Automated Virtual Environment), in which graphics are projected onto three walls and the floor of a room-sized virtual-reality theater to immerse the viewer in a three-dimensional audio and visual environment. Researchers use the CAVE and the ImmersaDesk as research and development tools for scientific experiments and design prototypes.
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