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.

The primary benefit of ultrasonic scalpels is that they cause thermal damage to only 1 to 2 millimeters of adjacent tissue, says IEEE member Tim Dietz, principal engineer at Ethicon Endo-Surgery (a division of Johnson & Johnson). The company, which manufactures an ultrasonic device called the Harmonic Scalpel, is funding the clinical trial.

Surgeons have used ultrasonic scalpels like the Harmonic for a variety of procedures since 1990, but cosmetic surgeons have been slow to adopt them. Dr. Al Aly, the principal investigator of the clinical trial, says that the study aims to determine if ultrasonic scalpels can reduce the formation of seromas, collections of clear fluid that are a common complication of many cosmetic surgeries. Doctors usually treat seromas by draining the fluid with needles.

Other small pilot studies of similar procedures, such as mastectomies for breast cancer, have indicated that ultrasonic scalpels can reduce seroma formation, but the benefits haven't been overwhelming, especially considering that seromas are neither painful nor dangerous. The repeated visits to the office that are required to treat seromas cost both surgeons and patients time and money, but when it comes to the motivation of the new pilot study, Aly admits that “it's a matter of technology driving use rather than the other way around.”

Further motivation comes from the state of the plastic-surgery market, where demand for procedures like lower-body lifts continues to expand as more Americans go under the knife to reduce their weight.

“If you're a company looking for areas of growth, that's probably the biggest area,” says Aly. Climbing obesity rates and improved safety in procedures like gastric bypasses led to 160 000 weight-loss surgeries in the United States last year alone, a number that Aly calls “a spit in the bucket” compared with the number of people who could potentially benefit. He estimates that as many as a quarter of patients choose secondary surgeries like lower-body lifts, which can cost between US $10 000 and $20 000. If Ethicon Endo-Surgery can show that ultrasonic scalpels are more effective than traditional techniques, the new market could provide a fertile selling ground for a 15-year-old technology.

When used in other procedures, ultrasonic scalpels have proved an adequate, if not revolutionary, alternative to electrocautery. For example, most comparison studies of their use in tonsillectomies over the past five years reported less bleeding during the operation and less collateral tissue damage, but the surgeons interviewed by IEEE Spectrum disagreed over how much such differences benefited patients. One surgeon says that in his field, “nobody's going crazy over it.”

“New technologies have been coming for many years, and they're always touting less pain and less bleeding,” says Dr. Patrick Collison, an otolaryngologist in Yankton, South Dakota, who has compared the ultrasonic scalpel to traditional instruments in tonsillectomies as part of a rigorous double-blind study. The only significant difference he found was less bleeding during the procedure with the ultrasonic scalpel—a benefit he says has minimal impact for patients.

Collison urges caution when faced with the hype of novel devices. “There are always doctors saying, ‘I'm blowing my competition away with this new technique,' ” he says, but it usually takes a few years to figure out the actual benefits.

It's too soon to tell whether Aly's study will help make ultrasonic scalpels standard for cosmetic surgeries, but anything that improves these procedures will only make them more popular and accessible. If obesity rates continue to rise, expect many more medical-device firms to try to cash in.