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Doctor's basement tinkering leads to development of intracranial pressure monitor

Neurosurgery and biomedical engineering Assistant Professor Joshua Medow

Neurosurgery and biomedical engineering assistant professor Joshua Medow.

Dr. Joshua Medow is on the cusp of a breakthrough that got started decades ago when he bought a Commodore 64 and learned computer programming.

His quest gained urgency when Medow was chief resident at University of Wisconsin Hospital and Clinics and he saw children in peril due to the buildup of pressure on the brain.

Now, after years of working on a prototype by himself at home after work, Medow and his colleagues are developing a solution to one of the most vexing problems in neurological surgery.

He and research collaborators in the UW-Madison College of Engineering are developing an implantable intracranial pressure (ICP) monitor.

The device - which Medow hopes to have in clinical trials within three years - will consist of a tiny sensor that will be embedded in a patient's skull and a reader that, when held near the location of the implant, will display the intracranial pressure.

As a UW Health neurosurgeon, Medow has seen how a headache can be a life-or-death event for a hydrocephalic child.

Hydrocephalus is a condition in which excess cerebrospinal fluid collects on the brain, causing an increase in pressure. There is no cure, but the condition can be controlled by surgically implanting a shunt that drains the fluid to another part of the body.

But half of all shunts fail within two years, causing the fluid to back up. That can lead to symptoms of hydrocephalus, including headaches. Emergency surgery is generally required to correct the malfunction. Failure to repair a malfunctioning shunt can lead to irreparable brain damage.

Doctors have to determine whether a headache or other symptom indicates shunt failure. There is currently no way to objectively measure intracranial pressure, so doctors cannot get that critical advance warning.

With the new device, a physician will be able to receive the pressure readings via phone or Internet and use the data for early detection of shunt failure, as well as to help patients avoid unnecessary shunt revisions.

Medow, an assistant professor of neurological surgery at the University of Wisconsin School of Medicine and Public Health, estimates that the device could help decrease misdiagnoses by at least 90 percent. 

"This is objective data. It's not really a guessing game anymore," Medow said.

Biomedical engineering professor emeritus John Webster

Biomedical engineering professor emeritus John Webster.

From Big Idea to Tiny Device

The device has come to life through a combination of Medow's own ingenuity, support from the Department of Neurological Surgery and collaboration with engineering faculty and graduate students.

While he was chief resident at UW Hospital and Clinics, Medow would buy parts from Radio Shack and, after his shift ended in the evening, he'd spend a few hours working on the prototype in his basement.

Eventually, he assembled an array of capacitors, resistors and electromagnetic coils on two circuit boards - one to take the pressure readings and another to decode them - which were mounted on a two-foot-square piece of wood.

Though Medow constructed the prototype by himself, the neurosurgery department helped make it possible by purchasing an oscilloscope and variac.

It was a crude device, to be sure, but it worked. Medow had a proof of concept. Dr. Robert Dempsey, chair of neurosurgery, and Dr. Bermans J. Iskandar, professor of neurosurgery, were supportive of Medow's idea of taking the next step and developing a wireless implantable device to measure pressure.

Dr. John Webster, professor emeritus of biomedical engineering, recognized the potential of Medow's idea and took the project under his wing.

"I didn't see anything that might stop it from being successful," Webster said.

When Medow began collaborating with the UW-Madison biomedical engineers, he was still funding the project out of his own pocket and with a small amount of startup funding he received when he joined the neurosurgery faculty in 2008. A grant would be necessary to keep the project moving forward.

It's hard  to envision how Medow's large prototype could be made to fit in a child's head, but biomedical engineering students Elena Bezrukova, Gerhard Van Baalen and Eric Roman, along with Dr. Kevin Turner, assistant professor of mechanical engineering, found a way.

The sensor is smaller than a fingernail and will be housed in an encasement that is about an inch long and matches the curvature of a human skull.

The students are also working on the reader, which will be about the size of a remote control when it is finished.

Development and production has taken place entirely at UW-Madison. The sensors are manufactured in a cleanroom at the College of Engineering, which is an environment with special lighting and air filtration to minimize particle contamination. Dozens of sensors are made from silicon wafers that are about the size of CDs.

"The people that I happened to find are just tremendous," Medow said. "Without their collaboration, I think the project would go stale. (Collaboration) wasn't so much a buzzword for me. I'm less interested in those buzzwords; I'm more interested in a quality product. And that's where we're at. And that's why this is really coming along nicely."

A Programmer at Heart

From the time Medow arrived in Madison in 1999 to begin a neurosurgery residency, he has distinguished himself. Among his honors are a 2011 Rising Star Clinical Excellence award from UW Hospital and Clinics and a 2010 Clinical Teaching Award presented by fourth-year students at the UW School of Medicine and Public Health. When he joined the neurological surgery faculty in 2008, he established the UW Health neurocritical care program.

Medow has routinely demonstrated excellence as a neurosurgeon, but, medicine wasn't his first career choice. He started computer programming when he was 10, after he saved enough money to buy a Commodore 64, and thought he was destined for a career as an engineer. It wasn't until his senior year of high school, when a cousin was diagnosed with acute myeloid leukemia (AML) and died within six months, that Medow considered becoming a physician.

He began medical school thinking he would specialize in oncology, but he soon realized that he missed computer programming. That steered him toward the neurosciences. Medow liked the idea that neurological surgery allowed him to work with his hands.

In that sense, Medow is still an engineer, but now he's working on the most powerful computer ever created - the human brain.

For video interviews related to this story, visit the School of Medicine and Public Health version here

UW-Madison School of Medicine and Public Health