Article about pervasive medical devices by David Geer

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Features Editor: Chandra Narayanaswami

chandras@us.ibm.com

News

FEATURED IN THIS ISSUE

■ Pervasive Medical

Devices: Less Invasive,

More Productive

■ Bridging the Digital

Divide

ireless, robotic, and computer-

backed medical devices are inter-

facing across the landscape, racing to

accident scenes, performing surgery, and

monitoring long-term care for young

and old alike. With the potential for

improved healthcare and long-term cost

savings, pervasive devices offer health-

care some intriguing new alternatives.

ROBOTIC SURGERY

Orthopedic surgeons operate with a

hammer, chisel, and saw. In knee re-

placement surgery, this means cutting

where the replacement should go with-

out cutting away too much bone or dam-

aging surrounding sinews and ligaments.

This difficult procedure, which depends

on a surgeon’s accuracy, raises consider-

able safety issues. That may be about to

change.

At the Imperial College, London, Justin

P.Cobb, chair of orthopaedic surgery, and

his colleagues have developed Acrobot

(Active Constraint Robot), a robotic sur-

gical system that constrains partial knee

replacement to safe, accurate parameters.

The surgical system consists of a stan-

dard PC, a real-time controller board,

surgical planning software, and a ro-

botic arm with drills and cutting tools.

Imperial College medical-robotics engi-

neers designed the Acrobot prototype,

and Imperial College surgeons tested it.

Human guidance

To plan the operation, a surgeon uses

the planning software to model the

patient on screen using the patient’s CT

scan. The surgeon then conducts virtual

surgery on the damaged knee, putting

the replacement in exactly the right

place. According to Cobb, this pre-

planning sets the software boundaries

that will enforce the hardware bound-

aries around what the surgeon may and

may not do in live surgery.

During live surgery, the Acrobot arm

is manipulated with a force control han-

dle that senses the force and direction of

the surgeon’s movements. The computer

uses this information to compare the

surgeon’s actions with allowed param-

eters and applies resistance using brakes

to keep the operation within preplanned

boundaries (that is, the space in which

the surgeon can operate safely and accu-

rately). A color-coded computer screen

display also helps guide the surgeon by

showing where the drill or cutting tool

is within these constraints.

The surgical system knows the robot

arm’s location at all times based on

information from encoders and soft-

ware. When the surgeon moves the drill

to within two millimeters of the safe,

accurate boundaries, the robot applies

its brakes and the surgeon feels a notice-

able resistance. Between two millime-

ters and the edges of those boundaries,

that resistance ramps up exponentially.

“You actually have to push to get to the

edges,” says Cobb.

Healthcare benefits

In most cases, patients have recov-

ered more quickly from robotic than

Pervasive Medical Devices:

Less Invasive, More Productive

David Geer

The purple hardware device suspended

above the patient’s knee is the Acrobot

arm. The knee is open for surgery with

rods holding it in position. The surgeon’s

hands [lower right] operate the force

control handle during surgery.

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conventional surgery. Patient expenses

were lower because they left the hospi-

tal sooner.

According to Cobb, surgeons can rely

on the technology to operate precisely,

with small incisions. Improving surgi-

cal accuracy improves patient out-

comes—replacements work better and

last longer—and could eliminate the

need for additional operations.

Another outcome is that the tech-

nology makes knee replacement sur-

gery less complicated, making it possi-

ble for less skilled surgeons to be very

good at it—so it’s ultimately less expen-

sive. “When you ‘deskill’ something,

you make it cheaper,” says Cobb.

Results

This surgical system will likely face

resistance from surgeons or patients

who mistrust the technology. However,

Cobb reports that their testing showed

that Acrobot helped surgeons place arti-

ficial knees within two millimeters of

planned placement 100 percent of the

time. Control group surgeries were this

accurate only 40 percent of the time.

WEARABLE MEDICAL DEVICES

While some medical devices such as

Acrobot require the patient to come to

the technology, many pervasive devices

bring the technology to the patient.

CodeBlue

Exploring wireless sensor network

technology for medical applications, the

CodeBlue project (www.eecs.harvard.

edu/mdw/proj/codeblue) is a collabora-

tive effort of Harvard University, the

Boston Medical Center, the Spaulding

Rehabilitation Center, the Boston Uni-

versity School of Management, the Johns

Hopkins Applied Physics Laboratory,

and 10Blade. CodeBlue seeks interest and

collaboration from medical researchers,

disaster response teams, and the business

sector.

CodeBlue’s research focuses on wire-

less sensor networks composed of

motes—small devices generally consist-

ing of a processor, memory, low-power

radio, antenna, and power supply. The

motes incorporate sensing, computing,

and radio capabilities in small form fac-

tors with low power requirements. This

facilitates mobility, allowing motes to

gather data such as vital signs continu-

ally over long periods within the patient’s

natural environment. Doctors and

nurses can use that data for real-time

triage and large-population studies over

time, according to Matt Welsh, assistant

professor of computer science at Har-

vard University.

Bridging the Digital

Divide

Benjamin Alfonsi

cross the globe, efforts are being

made to narrow the digital divide—

the wide split between those who have

effective access to computing technol-

ogy and those who don’t. Many people

rightly assume that, for the most part,

these efforts are aimed at developing

nations. But what about similarly situ-

ated people in rural or urban parts of

developed nations, including the US? Is

there sufficient overlap between the

technological problems confronting

developing countries and those con-

fronting economically challenged areas

in developed nations to spur a common

solution?

THE SAME … ONLY DIFFERENT

According to Matt Jones, associate

professor of computer science at

Swansea University in the UK, the issues

affecting disadvantaged people in both

developed and developing nations, with

respect to computing and technology,

are largely similar.

At Swansea’s Future Interaction Tech-

nology Lab, Jones and his colleagues

work on digital-divide issues, develop-

ing new mobile and ubiquitous com-

puting interaction concepts. “In devel-

oping contexts, so many people are on

the wrong side of the digital divide that

the problem is more apparent,” Jones

says. “And [that is] perhaps more attrac-

tive for the market.”

Ben Shneiderman, a computer sci-

entist at the University of Maryland in

College Park, agrees. “Poverty, illiter-

acy, poor health, and minimal tech-

nology experience are common aspects

in disadvantaged parts of the US as

well as developing nations, but the

severity [in developing nations] is

much greater and harder to remedy

because of the lack of infrastructure.”

According to Walter Bender, presi-

dent of software and content of the

One Laptop Per Child (OLPC) organ-

ization (http://laptop.org), cultural

acclimation to technology is a much

greater issue. “Alan Kay once said that

technology is anything invented after

you were born,” offers Bender. “But in

the case of [developing nations], it is

as much a matter of when your culture

would have been exposed to it.”

Although the issues affecting all

intended beneficiaries of digital-divide

programs might be similar, the solutions

to those issues might be very different.

“Solutions that work in the developed

countries cannot simply be transplanted

to developing-country environments,”

says Vincent W. Bagiire, CEO of

bridges.org. “Solutions must be based

on an understanding of local needs and

conditions.”

The metamessage, says Jones, is to

ensure that both the public and private

sectors understand the importance of

people-centered design. Involve the end

users from the beginning of the process.

Get the actual users to comment on

newly designed prototypes. “If a project

tries to impose a ‘solution’ without first

understanding their needs and wider

in brief...

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Pluto mote. One of the smallest motes

is Pluto, a lightweight device that can

be worn like a wristwatch. Patients can

wear several Pluto motes to monitor

such things as heart rate and respira-

tion, explains Welsh. These sensors cap-

ture the data and upload it to a PDA,

laptop, or PC residing in the patient’s

home.

The Pluto mote integrates the same

components found in larger sensors

(microprocessor, memory, battery, and

so on) onto a single circuit board, sav-

ing size and space. Other space savers

include a lightweight rechargeable bat-

tery and a surface mount antenna.

The Pluto mote employs an inte-

grated three-axis accelerometer (used

in motion studies). “We are working

with a group at the Spalding Rehabili-

tation Hospital, studying patients with

Chronic Obstructive Pulmonary Dis-

ease (COPD), Parkinson’s disease, and

stroke,” says Welsh. In those applica-

tions, researchers look at patient limb

movements during various activities.

With Parkinson’s disease, for example,

one complication is tremors, in which

the patient is afflicted with unexpected

and uncontrollable limb movement.

“Some of this is caused by the disease

and some is a side effect of the medica-

tion that is intended to control it,” says

Welsh. Pluto motes can help researchers

monitor limb movement in order to

better predict tremor episodes and

adjust medication dosages to head them

off.

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context, it is likely to fail,” he says.

This might be another reason why eco-

nomically challenged areas in developed

nations are often excluded from such pro-

grams. “The approach is always to be in

close touch with the users to understand

their genuine needs, then try pilot proj-

ects, and scale up,” says Shneiderman.

MOBILE MOTIVATION

Jones cites mobile technology as

often being the first step or harbinger

of a technological revolution. “In

developing contexts, mobiles have

been heralded as a ‘leapfrog’ technol-

ogy, a way for certain countries to

catch up with the developing world,”

Jones says. “The same is true for the

disadvantaged sectors in developing

countries themselves.”

The reasons why conventional com-

puting resources might not be having

an impact in developing countries, he

says, include limited reach of wired net-

works, prohibitively high cost, and soci-

etal factors such as lack of living space

and privacy issues—the PC is often

shared at home or controlled at work.

Mobiles, on the other hand, are re-

ferred to as “relationship appliances”

or “personal technologies” precisely

because they keep people connected to

friends, family, news, and entertain-

ment whenever and wherever they are.

“Because such relationships are funda-

mental to all communities, the mobile’s

universal appeal is not hard to under-

stand,” says Jones.

Although mobile devices have lim-

itations, particularly in terms of how

they present information, Jones says

societies will likely view access to

technology as an essential right, and

he expects to see more mobile com-

puting initiatives to narrow the digi-

tal divide.

However, Bagiire points out that com-

panies such as Voxiva (http://voxiva.

com) originally developed telephone-

based information systems for countries

with illiterate populations and little or

no Internet infrastructure, only to have

to redesign them for use in the US and

elsewhere.

“If a software company develops a

cheap, simple version of its popular

software for use on older hardware—

which it can sell to developing-country

markets where refurbished computers

are common—it does not want to see

[that software] resold in developed-

country markets where it might en-

croach on market share for heftier

products,” says Bagiire. In the devel-

oped countries, “they want to keep

people ‘buying up.’” He says the same

situation exists with hardware.

ccording to Bender, there is no

reason why certain technologies

aimed at benefiting underdeveloped

nations could not also benefit devel-

oped nations—except for having some

features that he says might be super-

fluous, such as a hand crank for bat-

tery power. So are there any plans for

OLPC to target needy children in the

inner cities or rural areas of the US?

“Certainly,” says Bender. “But it’s just

not where we are starting on day one.”

The Pluto mote, a lightweight sensing device that can be worn like a wristwatch.

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Vital Dust mote. The Vital Dust mote-

based pulse oximeter uses GPS to track

a patient’s location en route to the hos-

pital while continuously monitoring

heart rate and blood oxygen saturation.

Sensors record vital signs in real time

and pass them to a sensor gateway on

the ambulance, which forwards the data

to the hospital using either a cellular

EVDO (evolution data optimized) con-

nection or an Iridium satellite connec-

tion. If the Vital Dust hardware can’t

connect to the gateway immediately, it

can store the data in onboard memory

until it can, so that nothing is lost, says

Steven Moulton, associate professor of

surgery and pediatrics at the Boston

University School of Medicine.

In emergency response situations,

such pervasive medical devices provide

emergency room doctors with infor-

mation about the number of incoming

patients and their vital signs in advance.

This helps them better prepare for the

patient’s arrival.

IBM

IBM is integrating existing Bluetooth-

enabled sensors and smart phones with

its WebSphere technology (www.ibm.

com/websphere) to offer medical-device

solutions in pilot tests under the Personal

Care Connect Mobile Health Monitor-

ing Solution. According to Kathy

Schweda, a pervasive healthcare solu-

tions executive at IBM, the technology

and devices take data streams from Blue-

tooth communications, gather them on

a cell phone near the patient, and send

that data over an encrypted VPN tunnel

to a server. There, the healthcare pro-

vider, insurance company, employer, or

payer can use the information for such

things as managing chronic conditions

or monitoring the elderly.

IBM chose Bluetooth over other

wireless technologies, such as Wi-Fi,

because it consumed less power and

was less expensive. Additionally, with

its smaller transmission range, Blue-

tooth keeps data within a five- to six-

meter radius. “It is less likely to be

hacked,” says Schweda.

Kidney failure pilot. At the Imperial

College in London, IBM is combining

its mobile health monitoring with Blue-

tooth-enabled scales and blood pressure

cuffs from A&D Medical to monitor

young adults and children with kidney

failure. According to Schweda, these

devices monitor patient blood pressure

and weight to manage their fluid levels.

The data, received by an Ericsson smart

phone, is transmitted to a backend

server, which makes the information

available to medical professionals at

hand. Nurses can monitor many more

children at one time, checking the trans-

mitted data for trends such as weight

gain, rising blood pressure, and rising

heart rate and alerting a physician when

a patient needs attention.

These monitoring tools can also help

improve the patients’ quality of life.

“They can avoid coming in to see their

primary care physician or coming in for

dialysis earlier,” says Schweda.

Diabetic monitoring. IBM’s Personal

Care Connect technology also has a

pilot project to monitor diabetic

patients. Using Johnson & Johnson’s

Lifescan glucose meter as the end

device gives patients access to a very

small, portable device for testing their

blood sugar levels that can report the

results to healthcare providers. The

devices offer another long-term bene-

fit, by providing closer blood sugar

monitoring. This helps those moni-

tored correct elevated levels more

quickly and delay amputations, ac-

cording to Schweda. This technology

also lets doctors see graphs of the

device readings, providing a better

idea of how the data varies over time

and what it looks like over long peri-

ods, says Maria Ebling, research man-

ager of privacy-enabled context tech-

nologies at IBM.

ealthcare costs are positively im-

pacted when timely, quality care

leads to better outcomes and shorter

hospital stays. According to Moulton,

this will come through data mining.

Mined data, taken via these sensors

over time, has a predictive quality;

when healthcare providers see similar

data with patients in real time, they can

act on it immediately, improving their

precision.

Most of the technical challenges to the

CodeBlue wireless-mote project involve

developing sensor networks that can

successfully route patient data from

multiple sensors while avoiding network

collisions. “Three sensors are no prob-

lem. Once you get up to six sensors, then

the information collides and a lot of it

doesn’t get through,” says Moulton.

Other challenges include adoption,

which is impeded by the lack of techni-

cal training of many physicians. “As

newer, younger people come into the

system—people who are comfortable

with handheld computers and the Inter-

net, who are knowledgeable of the

power of computing—things are going

to change,” says Moulton. Developers

also need to create readable font sizes

for the elderly and devices easily used

by small children and older adults, says

Schweda.

The biggest challenge is getting

someone to pay for these technologies.

The diabetic-monitoring kits can run

upwards of US$1,500 for the blood

pressure cuff, scale, glucose monitor,

and phone. “The current reimburse-

ment models for the payers don’t

accommodate these kinds of preven-

tive measures in most cases,” says

Schweda.

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Nurses can monitor many

more children at one

time, checking the

transmitted data for

trends and alerting a

physician when a patient

needs attention.