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More MS news articles for August 2003

FDA Approves Stair-Climbing Wheelchair

August 13, 2003
FDA Website

The Food and Drug Administration (FDA) today approved a battery-powered wheelchair that relies on a computerized system of sensors, gyroscopes and electric motors to allow indoor and outdoor use on stairs, as well as on level and uneven surfaces.

FDA expedited review of the product, called the INDEPENDENCE iBOT 3000 Mobility System, because it represents a breakthrough technology with the potential to benefit people with disabilities. An estimated 2 million people in the United States use wheelchairs.

"This wheelchair represents a breakthrough in wheelchair technology," said FDA Commissioner Mark B. McClellan, M.D., Ph.D. "It can help improve the quality of life of many people who use wheelchairs by enabling them to manage stairs, reach high shelves and hold eye-level conversations. Its approval is emblematic of FDAís commitment to help innovative medical technologies reach patients promptly."

The user can push a button to command the wheelchair to operate in several different ways. It can be easily converted from a standard chair with four wheels contacting the ground to an elevated chair balanced on only two wheels. This is done when the user wants to reach high objects or wants to be at eye level for conversation. Four-wheel drive enables the user to traverse rough terrain, travel over gravel or sand, go up slopes, and climb 4-inch curbs. For use on stairs, there are two sets of drive wheels that rotate up and over each other to climb up or down, one step at a time. Because of its unique balancing mechanism, the wheelchair remains stable and the seat stays level during all these maneuvers.

To climb up stairs, the occupant backs up to the first step and holds onto the stair railing. Then he shifts his weight over the rear wheels, causing the chair to begin rotation of the front wheels up over the rear wheels and then down onto the first step. As the user shifts his weight backward and forward, the chair senses this and adjusts the wheel position to keep his center of gravity under the wheels. The chair ascends stairs backward and descends forward (the user always faces down the stairs).

To reach high shelves or hold eye-level conversations with people who are standing, the occupant shifts his weight over the back wheels so that the iBOT lifts one pair of wheels off the ground and balances on the remaining pair of wheels. The user then presses a button to lift the seat to a higher position.

People must weigh no more than 250 pounds and must have the use of at least one arm to operate the chair. They also must have good judgment skills to discern which obstacles, slopes, and stairs to avoid in order to prevent serious falls. Users must be capable of some exertion when climbing stairs in the wheelchair by themselves. However, for users who cannot tolerate such exertion, there is a feature that allows someone else to hold onto and tilt the chairís back to cause it to climb up or down stairs.

Physicians and other health professionals must undergo special training to prescribe the iBOT. The chair must be calibrated to the patientís weight, and patients have to be trained in its use and pass physical, cognitive and perception tests to prove they can operate it safely.

FDA approved the wheelchair based on a review of extensive bench testing of the product conducted by the manufacturer, Independence Technology (a Johnson & Johnson company), of Warren, N.J., and on a clinical study of its safety and effectiveness. Approval was also based on the recommendation of the Orthopedic and Rehabilitation Devices Panel of FDAís Medical Devices Advisory Committee.

The firm performed a wide range of tests on the chair, including mechanical, electrical, performance, environmental and software testing.

In the pivotal clinical study, 18 patientsómostly people with spinal cord injury-- were trained to use the iBOT and test-drove it for two weeks to allow researchers to compare maneuverability, falls and other problems to those encountered with their regular wheelchairs. They also tested it going up hills, over bumpy sidewalks, crossing curbs, reaching shelves and climbing stairs. Twelve patients could climb up and down stairs alone with the iBOT. The other six patients used an assistant. When these same 18 patients used their regular wheelchairs, one patient could "bump" down stairs, but no one could go up even one step.

During the pivotal study, three patients fell out of the iBOT and two fell out of their own wheelchairs. None of the falls occurred on stairs. Two patients experienced bruises while using the iBOT.

As a condition for approval, the manufacturer has agreed to provide periodic reports to the FDA to document the chairís usage, functioning and any patient injuries.

Copyright © 2003, FDA