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We saw this coming. More than 1 million procedures every year to implant artificial body parts. Two million patients with heart-regulation implants. And the big question:
You can fix a squeaky bike, but what about a squeaky hip? You can take a bum cell phone back to the store, but what about a heart implant? What do you do when the product you want to return is part of your body?
Latest example: an emerging fight over the interface between your heart implant and your heart. The FDA is on one side; Dr. Robert Hauser an Dr. Adrian Almquist of the Minneapolis Heart Institute, writing in the New England Journal of Medicine, are on the other. Their commentary is behind a subscription wall, so here's a summary of the debate from Barry Meier in the New York Times:
Federal regulators are about to approve use of a critical new electrical component for implantable heart devices without adequately testing for its potential risks, a prominent cardiologist warned Wednesday. The potential problem involves a new way of connecting defibrillators to the wires, or leads, that carry high-voltage electrical jolts between such units and the heart ...
Dr. Hauser argued that manufacturers should perform at least some clinical trials on patients to ensure that the new technology is not prone to short-circuiting, a problem that can prevent a defibrillator from delivering the life-saving electrical jolt ... The Food and Drug Administration, on the rationale that the new wiring connectors are simply a design modification and not a new technology, is not requiring human tests. Instead, it is requiring producers to carry out mechanical stress tests of the new connectors and study their performance in animals.
In other words, the FDA is treating the new technology as a detachable gizmo: You can test it in the lab, or in an animal, or whatever. Then you put in people and assume that since the last version worked, the upgrade will work, too. Hauser is treating it as a human body part: You have to test it in people, since that's where it's going to live, as it were.
Who's right? I don't know. Hauser has a better track record than the FDA does in assessing the safety of heart implants. But the key question, from what I can tell, is which standard of testing to apply. Should we let implant makers upgrade their devices just like other technology companies, or not? Think carefully. Because if you don't have an artificial body part today, there's a good chance you'll have one tomorrow.
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Looks like I missed a joint.
A couple of months ago, I wrote about the artificial parts we've been putting into people: hips, knees, shoulders, spinal discs, and elbows. U.S. government stats show more than 1 million such replacements per year. Piece by piece, we're mechanizing the body.
Next up: ankles.
Lauran Neergard of the AP has the story. There's a healthy (actually, an unhealthy) market for new ankles: More than 200,000 patients go to doctors for ankle pain every year. The prevailing surgical option is to fuse the ankle bones, which gets rid of the friction, and therefore the pain, but skews the way you move your foot. That, in turn, increases the strain on other foot joints, causing more pain and more fusions.
So why hasn't ankle replacement become as popular as hip or knee replacement? Because ankles are smaller and have to shoulder (so to speak) more stress. The original generation of artificial ankles broke down under normal wear and tear. A new generation is just now taking off. They cost up to $50,000 but are designed to operate more like a natural ankle, which would avoid the downstream damage associated with fusion. Neergard explains how they work:
Each model is slightly different but consists of two attached parts. Surgeons drill a tunnel into the lower leg bone and slide in the stem of the artificial joint. A bottom piece connects to the top of the foot. Thin plastic hooked to one side functions as cartilage. Bone then grows into the implant, holding it in place. In Europe, doctors also can use a similar but three-piece artificial ankle, where the plastic cushion is free-floating.
So the artificial cushion relieves day-to-day strains on the ankle, while the body, through bone growth, adopts the new mechanism as its own. Biology absorbs technology. Very cool. Let's hope it works.
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If you get the Human Nature RSS feed but don't check the Slate home page, you may have missed an article worth reading: How seniors became cyborgs. It's about the mechanical and electronic components we've been putting into old people to replace failing body parts. It's part of our "Geezers" issue. Take a look.
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One thing I hope to do in this blog is to keep connecting news stories and trends to each other. It's not enough to mock the idea of a civil right to body piercings. The larger theme of today's earlier post was the difference between necessary and elective body parts, and the difference between flesh and metal.
Both of those differences touch on an article in the current issue of Scientific American. Right now, the best we can do for amputees is fit them with prostheses designed to approximate normal limb motion. Such limbs don't feel anything, which in turn makes it harder to learn how to use them. The ideal solution isn't to outfit these people like cyborgs; it's to give them good old flesh. That's what the authors-Ken Muneoka, Manjong Han, and David Gardiner-are working on. They conclude that "we may be only a decade or two away from a day when we can regenerate human body parts."
The path will require many steps. At the moment, the authors are still working on inducing basic regeneration in mice. Growing larger structures-paws, and later arms-will be progressively more difficult. But in principle, the project should be doable, since it's modeled on an animal that already regenerates its own limbs: the salamander.
If we're going to start handing out new bodily civil rights, as the nipple-ring lawyer proposes, I'd put replacement flesh way ahead of ornamental metal.
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