October 29, 2011
MADISON, Wis. (AP) — Ten years ago, working on a night shift as a resident in a Madison emergency room, Josh Medow found himself treating a child with hydrocephalus, a disease in which fluid accumulates in the brain. The child had a headache and the anxious parents feared the worst — that a shunt designed to drain the fluid had failed and potentially lethal pressure was building up in the boy's brain.
Medow realized there was no way to check whether pressure was indeed increasing, short of intrusive and painful procedures. The child ended up in the operating room.
Today, Medow, 38, and an attending neurosurgeon at UW Hospital, is on the verge of patenting a device he invented that allows doctors and even parents to easily keep track of cranial pressure in a child with hydrocephalus.
The long journey from that night in the emergency room to the invention of the tiny silicon implant that now sits on his desk is partly a tale of how medical devices come to be. But it is also a story of invention, full of twists and turns, moments of insight (that light bulb going on over the head), night-long sessions in Medow's basement where he initially cobbled together a prototype, and a trip or two to Radio Shack.
Medow has long had an interest in how things work. Before getting his medical degree at UW-Madison, he earned a degree in applied life studies and biomechanics at the University of Illinois. When he was a boy, he liked to build radios. When he was 10, he bought himself a Commodore 64, a very early computer, and taught himself computer programming.
"I used to tinker," Medow said. "I worked at a Radio Shack when I was in high school."
Though he is now a doctor, Medow still views the world through the eyes of that tinkering boy. He sees problems that could be solved by devices and he thinks about how to build them.
About 700,000 people have hydrocephalus, a disease in which the body is missing the ability to re-absorb the cerebral spinal fluid that bathes the brain. That fluid is normally made and drained three times a day, Medow said.
But in those with the disease, it builds up and creates dangerous pressure that can lead to brain damage, stroke and blindness. Normally, a shunt keeps the fluid drained, but studies show half of all shunts fail within two years. Sometimes, for example, they get clogged; fluid builds up and pressure increases.
Medow couldn't stop thinking about the problem. There had to be a better way, he thought, to know whether a shunt has failed than doing surgery on the shunt itself, an operation that can cost as much as $15,000 and cause considerable pain.
That night, when he got home, he made the initial drawings for a device that could eventually be made small enough to be implanted to monitor pressure and allow parents and doctors to know whether a shunt had failed without doing invasive surgery.
The initial idea was fairly simple and drew on a basic principle of magnetism and electricity arrived at by English scientist Michael Faraday in 1831: electromagnetic induction. Faraday found that when he manipulated the magnetic field around an electromagnet by closing and opening an electrical circuit he had built around the magnet, an electrical current could be detected in a separate conductor nearby.
Perhaps, Medow thought, he could build a device using electromagnets that would collect electrical signals from the brain and send them to a separate device that would translate the information into something useful — such as a pressure reading. He could use a device called a transducer to translate pressure into electrical current. The higher the frequency, the higher the pressure in the brain.
Medow went to Radio Shack and bought $75 worth of electronics gear. Working at a coffee table in his basement he cobbled together a prototype on a piece of plywood.
But, for a long time the prototype remained a prototype, a bunch of electrical equipment mounted on a piece of plywood that Medow had painted red. He was deep into his residency, working 100 hours a week at the hospital. Sometimes, he'd take friends down to his basement and show them what he'd made.
"They'd say, 'That's really nerdy, now let's go out for a beer,'" Medow recalled.
Eventually, however, Medow found numerous supporters on the UW-Madison campus who helped him move the work forward. They included John Webster, a professor emeritus of biomedical engineering, who became a champion of Medow's after he realized the value of the invention. Other supporters included Dr. Robert Dempsey, chair of neurosurgery at UW Hospital, and Dr. Berman Iskandar, professor of neurosurgery.
Last April, Medow was awarded a $300,000 grant from the Hartwell Foundation that would help the Department of Biomedical Engineering downsize the prototype into a tiny implant made from pliable silicon and shaped to fit neatly beneath a rounded skull.
Signals from the implant — called a transcutaneous inductive pressure monitor — will be read on a handheld device about the size of a television remote.
The final product of Medow's imagination now sits on his desk. He hopes to see it tested in human trials over the next three years.
"It's neat being a doctor and knowing there is a problem to solve," Medow said. "And it's neat knowing how to build a device that seems to have the potential to work. I just knew there had to be a better way."