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Alternative Knife for Plastic Surgery After Weight Loss

Medical-device manufacturers look to cash in by trimming the fat

3 min read

11 October 2007--A new clinical trial aims to determine whether using an ultrasonic scalpel--a blade that makes tiny vibrations thousands of times a second--could reduce the need for wound drainage following lower-body lifts, the most common side effect of a cosmetic-surgery procedure to remove excess skin from the thighs and buttocks. The recent increase in weight-loss surgeries has created a secondary demand for procedures like lower-body lifts, and an emerging market for companies that make surgical devices.

The clinical trial will compare an ultrasonic scalpel with the traditional technique, called electrocautery, in which surgeons send a current of electricity through the tissues being cut. The tissues heat up because of their resistance to the current, and the heat collapses and seals blood vessels to prevent bleeding. Ultrasonic scalpels produce heat through friction rather than an electric current--the scalpel relies on piezoelectric stacks that convert electricity into mechanical energy, causing the tip to oscillate between 55 and 90 micrometers side to side at a rate of 55 500 times per second.

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Restoring Hearing With Beams of Light

Gene therapy and optoelectronics could radically upgrade hearing for millions of people

13 min read
A computer graphic shows a gray structure that’s curled like a snail’s shell. A big purple line runs through it. Many clusters of smaller red lines are scattered throughout the curled structure.

Human hearing depends on the cochlea, a snail-shaped structure in the inner ear. A new kind of cochlear implant for people with disabling hearing loss would use beams of light to stimulate the cochlear nerve.

Lakshay Khurana and Daniel Keppeler

There’s a popular misconception that cochlear implants restore natural hearing. In fact, these marvels of engineering give people a new kind of “electric hearing” that they must learn how to use.

Natural hearing results from vibrations hitting tiny structures called hair cells within the cochlea in the inner ear. A cochlear implant bypasses the damaged or dysfunctional parts of the ear and uses electrodes to directly stimulate the cochlear nerve, which sends signals to the brain. When my hearing-impaired patients have their cochlear implants turned on for the first time, they often report that voices sound flat and robotic and that background noises blur together and drown out voices. Although users can have many sessions with technicians to “tune” and adjust their implants’ settings to make sounds more pleasant and helpful, there’s a limit to what can be achieved with today’s technology.

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