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October 29, 2002

Smart parts

From: The Globe and Mail, Canada
Oct. 29, 2002

Science fiction is becoming medical fact as
a new generation of artificial implants interact
with the human body, SHAFIQ QAADRI writes


Tuesday, October 29, 2002

Eyes, ears, hearts, kidneys, penises, brains -- there are artificial replacement parts for all these organs. Man-made machinery is being installed in human bodies, and science fiction is becoming medical fact.

Rapid progress is being made in the new disciplines of biomedical engineering and robotics, and thousands of individuals with diseased organs may benefit. "What we're trying to do is advance medical science with engineering and biological tools," says Dr. Ajit Yoganathan, director of the Georgia Tech Bioengineering Center.

Certainly, there is a need for spare parts: With an aging population, the number of people awaiting organ transplants is rising, as is the need for prosthetic limbs.

But the artificial-organ industry is also catering to greying baby boomers, who will not age quietly, but instead wish to retain their mobility, vision, memory and sexual prowess.

And, as the ethical debate over fusing man and machine continues, intricate questions arise. "There's no [legal] act even proposed about body parts," says Dr. George Annas, professor of health law at the Boston University School of Public Health. If a person with a prosthetic limb commits a crime, for example, will a clever lawyer be able to blame the implant, deflecting guilt from the individual?

And if society struggles with genetically modified foods, how will it deal with mechanically modified people? Will labelling be mandatory: 5-per-cent robot?

There are no simple answers, only an unpredictable future, as the original biomedical engineer, Dr. Frankenstein, anticipated almost 200 years ago in the Mary Shelley novel: "I had worked . . . for the sole purpose of infusing life into an inanimate body . . . but when those muscles and joints were rendered capable of motion, it became a thing such as even . . . [philosophers] could not have conceived."

Consider this sampling of human-machine hybridization.

Passive parts

There is a long history of implanted materials: glass eyes, synthetic hair, dentures, silicone-gel breasts and permanently fixed metal rods that stabilize fractured bones. Cosmetic surgeons are now implanting special moulds for a more masculine chin, higher cheekbones, a more beautifully angled nose and less prominent frown lines. But all such passive gadgets, once in the body, just sit there, unlike the new-generation implants.

Activated tissues

The era of artificial skin is here, which will greatly aid severe burn victims. Almost "alive," artificial skin is made of specially layered fibres, which are activated once grafted onto a burn site. The substitute skin acts as a temporary scaffold, allowing a person's own skin to regrow in its place, healing without scars, as the artificial fibres are absorbed.

A related product is artificial cartilage, which is injected into arthritic knees, allowing the person's natural cartilage to regenerate, cushioning the joint from further wear and tear.

What is remarkable is that artificial skin and cartilage can be custom-designed. "It is now possible to tailor the thickness, areas, shapes and internal architecture of these devices . . . [for] various wound circumstances," says Dr. John Brekke, whose firm, THM Medical, is a leader in tissue regeneration.

But such activated parts, though a welcome medical development, may have unforeseen consequences, which are now debated at medical conferences. Want to change your skin colour, perhaps to a tint not found in nature? How about yearly facial skin replacement for youthful looks? Or reshaped ears for that alien look? A dorsal fin for better swimming?

Private parts

Having a metal or inflatable rod inserted inside your penis -- for an erection on demand -- is usually restricted to men with severe impotence, which can be caused by diabetes, excessive smoking, spinal cord injury or prostate-cancer surgery. But baby boomers have decided that satisfying sex for life is not only a medical need, but an inalienable right, and the artificial-organ industry is obliging.

Men whose erectile difficulties are mostly psychological, and who are not helped by medication, are now receiving penile prostheses. With the semi-rigid malleable metal implant, "the erection can last as long as wanted," says Dr. Claudio Urlich, a professor of urology at the University of Costa Rica.

The inflatable rod variety has miniature hydraulic pumps, and is deflated "by pressing relief valves," according to Dr. Steven Morganstern, a urologist at the Atlanta Men's Health Center, and author of Overcoming Impotence. Dr. Morganstern estimates that 90 per cent of his implant patients have "fulfilled expectations," noting that performance-anxiety is eliminated.Remarkably, these devices are so well stitched into the body, that men can still father children.

Internal organs

There are thousands of people with heart pacemakers, which release electrical impulses into the heart, like a ticking metronome, to keep it beating regularly.

Beyond pacemakers, however, the experience with artificial mechanical hearts has been disappointing. Patients have not survived for long, succumbing to blood clots or infections. For now, Heart Assist Devices (HADs), small pumps that help the existing damaged heart, are used.

But advances in miniaturization and computerization are leading to more ambitious projects: Research is under way for fully autonomous artificial hearts, kidneys and livers.

An intriguing advance is a heart transport method known as the Portable Organ Preservation System (POPS), developed at the Center for Advanced Biomedical Research at Boston University Medical School. When doctors harvest organs from people who have just died, they place the retrieved hearts and kidneys into the POPS, to preserve the organs for a few days. And then the organs come to life.

"In the simplest terms, it makes the organ believe it is still in the body," says Dr. Waleed Hassanein, a heart surgeon who developed the machine. "The heart naturally starts beating," and kidneys start producing urine, which can be tested. The organs actually become healthier once outside their original owner.

The ethical dilemmas continue to build, and health and legal scholars are on new ground. For example: Does a living but unbodied organ have rights? Can it be sold to the highest bidder?

If freshly harvested organs can be preserved for longer periods, will the overseas industry in black-market organs flourish further?

Flexing parts

Hip- and knee-replacement surgery is common, as an aging population leads to more people with degenerated arthritic joints. But these replacement joints are still just passive parts, even though they move. The artificial hip, for example, is just a sophisticated ball-and-socket contraption.

But the next level of integration is bionics (bio-mechanics), in which the body talks to the machine, actually giving the artificial part its cue to function. Dextra is a prosthetic hand, which was developed at Rutgers University, and is one of the first artificial limbs to use a person's own nerves to feed electricity to the machine's fingers.

"Communication is key," says Dr. William Craelius, the biomedical engineer who developed Dextra. "Human-machine communication could soon lose its distinction as the No. 1 obstacle to bionics." With a seamless human-to-device connection, Dextra patients have such natural control that they can type and play the piano.

With the development of synthetic muscle, entire joints need not be replaced, but select muscles can be restored.

So far, scientists at the Artificial Muscle Research Institute at the University of New Mexico hope to help people who have lost muscle function. But as the technology progresses, researchers could also reinforce existing muscles, perhaps inserting muscles into new locations, leading to entirely new movements and power.

"Imagine if our [research and] computers become greenhouses for a new kind of nature," says Dr. Peter Bentley, a computer scientist at University College, London, and author of Digital Biology: How Nature and Technology are Transforming Our Lives.

Sensing technologies

There are now computerized silicon implants for all five senses -- hearing, sight, smell, taste and touch. And the gadgets are amplifying our conscious awareness.

The cochlea is the snail-shaped hearing part of the ear, and cochlear implants for the deaf, known as the bionic ear, are common. The device is surgically implanted near the ear canal. Its microphone picks up sound, bypassing the deaf ear, and sends signals directly to the brain. They are so successful that 80 per cent of recipients hear well enough to have conversations.

Such instruments, which are fluent in the brain's own language of electricity, are a major -- even ominous -- scientific advance. "These . . . devices join the two worlds of information processing, the silicon world of the computer to the water world of the brain," says Dr. Peter Fromherz, a physicist at the Max Planck Institute for Biochemistry in Germany.

The bionic eye implant, the Artificial Retina Component Chip (ARCC), was developed at the Johns Hopkins University, and mimics the retina, allowing the blind to see. ARCC is a silicon chip that has 100,000 light sensors packed into a 0.4-millimetre sliver. The sensors respond to light the way the retina does, converting the energy into faint electricity, sending the impulses to the brain via the optic nerve.

But Dr. William Dobelle, a pioneering biomedical engineer, has gone further, and developed an artificial-vision system that bypasses the human eye entirely. A camera is worn on special glasses, images are sent to a computer worn on a belt, and impulses travel by electrodes that have been surgically stuck into the brain's vision centres, the visual cortex at the back of the head.

The result? A hazy, outline-only image, but the formerly blind recipients are elated. Dr. Dobelle ambitiously declares, "As our technology improves . . . braille, the long cane and the guide dog will become obsolete as surely as the airplane replaced the steamship."

The human machine

As scientists modify and bypass our sense organs, learning how to communicate directly with the brain, they are considering brain implants -- pacemakers for the brain -- for various conditions.

For example, why not permanently implant electrodes in the specific sites known to provoke seizures, depression, hyperactivity, Parkinson's or Alzheimer's disease? Perhaps the electrodes can self-regulate, zapping the problem before it builds, or they can be turned on with conscious will, or even by another person remotely. "Now we're treating the brain like circuitry," says Ray Kurzweil, a computer scientist and author of The Age of Spiritual Machines: When Computers Exceed Human Intelligence.

Other scientists want to move beyond diseases, and upgrade the human form, expanding consciousness. For example, implanted devices could extend human perceptions, giving people superhuman senses. Perhaps you would like the high-frequency hearing of a dog, or the sonar echolocation of a dolphin, or the night vision of an owl? Or even internal wireless Internet access with a mouse controlled by your thoughts?

"Our machines will become much more like us, and we will become much more like our machines," says Dr. Rodney Brooks, director of the Artificial Intelligence Laboratory at MIT, and author of Flesh and Machines: How Robots Will Change Us.

It seems that neither science nor the imagination has any boundaries, as reality overtakes fiction.
Dr. Shafiq Qaadri is a Toronto family physician with a special interest in medical education.

© 2002 Bell Globemedia Interactive Inc.