While on patrol in Afghanistan in June 2012, Marine Corps Captain Derek Herrera was struck by a Taliban bullet, leaving him unable to use his legs.
Two years later he is able to walk, with the help of a robotic machine that uses computers and electric motors to power his paralyzed limbs.
“I see hope for the future,” said Herrera after striding through the lobby of a Marlborough hotel in June. “Mentally and emotionally it’s been inspiring and incredible.”
Herrera is one of about 400 people worldwide who use ReWalk, a prosthetic technology developed in Israel by Marlborough-based Argo Medical Technologies Inc. ReWalk is an exoskeleton — a set of electrically powered braces that strap to the user’s legs and use computers and motion sensors to control his movements.
ReWalk has been used in rehabilitation hospitals in the United States for several years and available publicly in Israel, the United Kingdom, and several other European countries. Now it’s available for personal use in the United States, after a recent approval from the Food and Drug Administration.
This means that any disabled person will be able to purchase one, as an alternative to a wheelchair. Several other companies are working on similar devices, but ReWalk is the first to get general FDA approval, and Herrera plans to be the first American to purchase one.
He’s the ideal early adopter. Herrera graduated from the US Naval Academy in 2006 with a degree in systems engineering. He is still on active duty with the Marines, and is completing a master’s degree in business administration at the University of California in Los Angeles. Herrera has even visited Argo’s lab in Israel to consult with the ReWalk engineering team.
The entire ReWalk rig weighs about 44 pounds. This includes the motorized leg braces, and a backpack that contains a control computer and a couple of lithium-ion batteries to provide up to four hours of mobility.
Herrera manages the ReWalk by pressing buttons on a wrist-mounted wireless controller. On his command, the prosthetic can lower his body onto a chair, or pull him upright. The controller also contains an alarm to warn the user when the batteries are running low. If power is lost, the ReWalk will run a “graceful collapse” algorithm that gently lowers the user to the floor.
To walk, Herrera leans forward onto a pair of canes gripped in his hands. The canes are just for balance; his braced-up legs take nearly all the weight. A motion sensor like those used in smartphones is strapped to the side of Herrera’s chest. It detects his forward-tilting torso and begins moving his legs forward in a series of small steps, with the right leg going first. The electric motors at the hip and knee joints lift and lower his legs, their movements precisely controlled by the backpack computer, which is programmed to simulate the human gait.
ReWalk is designed for a top speed of about 1.3 miles per hour, fast enough to make it safely across an intersection before the light changes. Herrera is still trying to master the device; an assistant stands behind him, helping him keep his balance. He takes small steps but makes good progress, marching across the hotel lobby and out the front door, where he strolls down the sidewalk and back again.
This impressive technology doesn’t come cheap; the ReWalk costs $69,500. Herrera is getting help from the MARSOC Foundation, a charitable fund for members of the Marine Corps Special Operations Command.
His health insurance won’t cover the device. But insurers may take another look, now that the FDA has signed off on ReWalk.
“We believe that this will pay for itself,” said Larry Jasinski, Argo’s chief executive. “I have anecdotal data that shows savings of about $30,000 a year.”
Jasinski said that a high-end powered wheelchair, the kind used by people with severe spinal injuries, costs between $20,000 and $40,000, with some even more expensive. But constant sitting in a wheelchair can cause serious medical problems.
Patients “have severe skin problems often,” said Michael Goldfarb, professor of physical medicine and rehabilitation at Vanderbilt University. “They can get what are basically life-threatening skin ulcers.”
Movie star Christopher Reeve was paralyzed after a 1995 horseback-riding accident, and died of heart failure in 2004 after a skin ulcer became severely infected.
Constant sitting causes other complications: weakened bones, digestive disorders, urinary tract infections.
Jasinski said the exoskeleton will help fend off many of these problems, resulting in big reductions in medical bills.
He argued ReWalk could pay for itself in as little as two years, a payback that he thinks will make it popular with health insurers.
Maren Anderson of MDA Consulting Inc. in Boston works with Argo and other companies to persuade insurers to cover their medical devices.
“We think that we’re going to be covered fairly routinely on a case-by-case basis,” she said. “The doctor’s going to certify that these people have a medical need to walk.”
But insurers will wait to see how patients respond before adding the ReWalk to their list of routinely covered devices, Anderson said, a process that could take several years.
Tony B. Dodek, associate chief medical officer at Blue Cross Blue Shield of Massachusetts, said coverage of new medical devices is decided by a committee at the central Blue Cross Blue Shield Association in Chicago.
“They look at all of the scientific evidence that’s been produced and they rate the quality of the evidence and then they compare that to what currently exists,” Dodek said. “First and foremost we want to make sure that a device is safe . . . secondly we want to make sure that it’s effective.”
Dodek said that process could take three to six months. Then it’s up to each of the 37 Blue Cross Blue Shield member companies to decide whether to reimburse for ReWalk.
While Argo’s engineering team is based in Israel, Jasinski said that Massachusetts is the ideal place for the company’s sales, marketing, and clinical testing teams.
Argo foresees a big global market for exoskeletons, not only for people with spinal injuries, but for people with neurological diseases such as multiple sclerosis and elderly people with limited mobility.
For instance, Argo has formed an alliance with Japanese robot maker Yaskawa Electric Corp., to serve Japan’s rapidly aging population.
Apart from the physical benefits, ReWalk can help restore a disabled person’s sense of dignity and self-confidence, simply by putting them back on their feet.
“Since I was confined to a wheelchair, I look up at everybody and I’m shorter than anybody else,” said Herrera. “Being able to look people in the eye again — things like that are small, but until you lose that you don’t really understand how great it is to have that back.”