Medical Device Daily Contributing Writer

Canadian researchers are developing a scoliosis brace that monitors the amount of time patients wear the device and also keeps pressure levels within the desired range in order to prevent spinal curvature from increasing. Increased curvature may result in scoliosis patients requiring surgery, but studies indicate bracing effectiveness can be hampered by a lack of data on how often the brace is worn and whether it is being worn properly.

The "smart brace," developed by engineers and surgeons at the University of Alberta and Glenrose Rehabilitation Hospital (both Edmonton), can be employed with "any type of brace," said engineer Dr. Edmond Lou – coupled, he told Medical Device Daily, with pressure sensors and an electronically controlled pump that adjusts the air pressure inside an inflatable pad.

"The computer system connected to four sensors will sense how tightly the patient wears the brace." Lou said. "What we measure is the interface pressure inside the brace. If it's below or above the prescribed tightness level it will automatically adjust the air bag pressure (to the correct pressure)."

The smart brace logs both the force value and the amount of time the patient wears the brace. Initially it was hoped that the amount of time patients choose to wear the brace would increase as a result, from about 15 hours to 22 hours each day.

However, patients in the study showed little inclination to wear the device longer, despite the fact they knew they were being monitored. In some instances they achieved wearing scores of 18 to 19 hours, but demonstrated an overall average wearing time still at about 73%. Lou attributes this is part to reservations among patients about the effectiveness of brace technology.

All that may change as patients learn more about the smart brace, he said. Because where wearing time didn't change during the study, Lou said, wearing "quality" changed significantly.

"Before the feedback system was activated, we measured and found that 53% of the patients wore their brace at the prescribed pressure level. When we added the feedback system in the following two weeks of the study, 68% of the time patients wore the brace at the prescribed level."

Best of all, said Lou, average spine curvature remained unchanged at the end of the study at just over 30 degrees. He believes the device will prove itself effective in preventing increased spinal curvature in scoliosis patients, a view shared by Marc Moreau, MD, a pediatric orthopedic surgeon and clinical professor at the University of Alberta. Much remains to be discovered about patient's wearing habits, however, and how this can be improved.

"Nobody knows how it works," said Moreau. "We're heading down that trail to find out how it works."

Calling the smart brace mainly a research tool, Moreau and Lou said their team is working with colleagues in Hong Kong to expand the pool of available patients. If it continues to prove useful, the device could be marketed commercially.

Still in Edmonton, researchers are partnering with South Korean firm LG Electronics to test a wireless device that allows patients with chronic illnesses to transmit data such as blood pressure, pulse and temperature to their doctor. The Alberta government, which is contributing $1.5 million to the project, said the hand-held device, called the Home Health Monitoring Solution, features newly developed sensing technology. The three-year development plan includes technical validation, testing, clinical trials and preparation to commercialize the device.

In other Canadian health news, Health Canada has declined to issue an advisory after doctors warned about a link between high-flow postoperative pain pumps and a recent rise of significant cartilage breakdown following arthroscopic shoulder surgery.

Researchers at the Fowler Kennedy Sport Medicine Clinic (London, Ontario) say postarthroscopic glenohumeral chondrolysis (PAGCL), first reported in medical literature in 2004, is leaving some active people in their 20s and 30s with no option but a shoulder replacement.

Clinic medical director, Robert Litchfield, MD, said surgeons using devices that infuse local anesthetic agents into joint spaces should be made aware of the complication and that Health Canada "should mandate that device manufacturers provide warnings to that effect." In one case, Litchfield treated a 30-year-old man whose shoulder cartilage breakdown ended his professional hockey career in the American Hockey League. The patient had undergone routine arthroscopic repair of a dislocated shoulder in the U.S. and had a pain pump catheter inserted into the joint for the first two postoperative days.

"Within six months, his joint was destroyed ... He'll end up with some form of joint replacement at a young age."

"We haven't really had a reason to replace young people's shoulders in the past," Litchfield added. "The real tragedy is that in most of our arthroscopic procedures, the pain is minimal ... and for many of our 'scope shoulder operations, people are only using oral pain medications for a couple of days afterward."

Litchfield said that although the use of pain pumps is less common in Canada than in the U.S. due to cost issues, he had heard there were a couple of dozen cases in Saskatchewan. "I think if you went across the country, the shoulder surgeons have all seen some cases."

PAGCL was linked with pain pumps in a case series of patients operated on by Charles Beck, MD, of the Center of Orthopaedic and Rehabilitation Excellence (West Jordan, Utah).

"Aside from the same surgeon performing all of the procedures on the patients ... the one consistent factor in every patient with chondrolysis is that all of the patients received intra-articular pain pump catheters that eluted 0.25% bupivacaine and epinephrine, and all were arthroscopic capsular procedures," Beck and colleagues wrote in the October 2007 issue of the American Journal of Sports Medicine.

But while the complication is well-documented among arthroscopic surgeons in the U.S. and lawsuits have been filed there against device manufacturers, Health Canada said it had not received reports of any problems related to the disposable infusion systems, and was not planning to issue any advisories.