Soon, flexible braces for kids with curved spine

Washington: Researchers, including one of Indian-origin, are developing a spine brace with sensors that provides more flexibility than the braces currently in use for children suffering from scoliosis, a sideways curvature of the spine.

Some six million people in the US suffer from scoliosis. These include approximately 2 to 3 per cent of adolescents who are diagnosed each year with idiopathic scoliosis, which is usually identified during puberty and progresses until skeletal maturity.

One in 500 children today require treatment using spine braces and 1 in 5,000 need spinal surgery.

The typical spine brace is made of rigid plastic that fits around the child's trunk and hips and applies counter-pressure on the spine's abnormal curve, on the theory that pressure and support on the curve from outside will stimulate more normal growth of the spine.

The rigid braces have several shortcomings. They "freeze" the child's upper body and limit movement.

As the child grows, the required external forces to correct the abnormal posture change along the length of the curve and over the course of treatment.

Sunil Agrawal, professor of mechanical engineering and of rehabilitation and regenerative medicine at Columbia University School of Engineering and Applied Science, and colleagues are developing a dynamic spine brace that is more flexible than the rigid braces now in use.

They have won a USD 1 million grant from the US National Science Foundation's National Robotics Initiative.

"If we can design a flexible brace that modulates the corrective forces on the spine in desired directions while still allowing the users to perform typical everyday activities, we will bring revolutionary change to the field," said Agrawal.

The researchers have developed prototype wearable spine braces that consist of rings that fit on the human torso.

These rings are dynamically actuated by servomotors placed on adjacent rings to control the force or position applied on the human body.

Onboard sensors record the force and motion data and transmit the information to a host computer for monitoring and adjusting the treatment.

The team has also developed a second brace that is fully passive, made of compliant components able to adjust stiffness in specific directions.

However, both these braces have drawbacks. The dynamic brace needs an active power source while the passive brace cannot provide active controls.

"While we are the first group to propose parallel-actuated spine braces and compliant braces, these are just in initial phases," Agrawal said.

Researchers will now design hybrid semi-active spine braces that combine the merits of the two.

"These will be less power hungry and can be worn over a longer duration of time," Agrawal said.