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WorldWeird: Bionic Cat: Transcutaneous / Exoprosthesis

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      CommentAuthorSara 013
    • CommentTimeJun 25th 2010
     (8466.1)
    Did a bit of searching here, but couldn't find this posted. (Sorry if I just missed it.)

    http://news.bbc.co.uk/2/hi/science_and_environment/10404251.stm

    Kitty gets eaten by a combine harvester, loses the lower half(ish) of both back legs.

    Vets and Mad Scientists (biomedical engineers, woo!) give kitty prosthetic feet. The important part of all this is that they are transcutaneous - meaning, these prosthetics are implanted within the limb and extend beyond the natural edge of the amputated limb, through the dermal tissue.

    Exoprosthesis.

    And the skin grew into the metal. In my (limited) experience, this just doesn't happen because the porosity of metals (lack thereof) really isn't conducive to tissue ingrowth. (All those rejected piercings? Yeah....) Tissue typically needs some sort of scaffolding to grab hold of and grow into / around. Creating a metal structure that is, I imagine, artificially porous - or, I guess, there are recent advancements in molecular coatings that create artificial scaffolding of sorts on metals, too - in order to promote tissue growth / endothelialization / assimilation into the biological system for this purpose is... well... really kind of an awesome step forward.

    Let's just hope that dogs don't catch wind of this biotech advancement.
    • CommentAuthorFan
    • CommentTimeJun 25th 2010
     (8466.2)
    The parents of a friend of mine have a dog with a broken spine (who gets about happily using a cart). A hospital/vet in Cambridge is going to try to repair the spine, with stem cells.

    When I heard *that* news I was like, "Yea, hopefully they'll be doing that for humans not many decades from now."

    It's nice that they're experimenting on pets who need the treatment as a result of accident, rather than on lab animals whom they've mutilated for the purpose.
    • CommentAuthorFan
    • CommentTimeJun 25th 2010
     (8466.3)
    Sara, the article Intraosseous transcutaneous amputation prosthesis (for example) says,

    "To this end, ITAP was specifically designed to closely mimic the anatomy of the deer antler, a rare natural circumstance where skin integrates directly with underlying bone to create a resilient, infection-resistant seal between the skin and the antler. This seal persists when the antler has matured and is dead bone
    attached to living bone of the skull through the skin. Antlers are used for fighting and as such sustain high levels of loading. This natural scenario was identified as an ideal biomimetic model for development of skeletally integrated exoprostheses for amputees."
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      CommentAuthorSara 013
    • CommentTimeJun 25th 2010
     (8466.4)
    Huh.
    That's kinda nifty. We're finally getting further into designs based on biological models rather than artificial engineering constructs. Excellent.

    I (heart) mad science.

    ...especially as someone who works on lab animals for the purpose of technological experimentation and advancements...
  5.  (8466.5)
    I'm concerned about the possibility of infection and biofilm formation with any technology like this. Anybody know if they found a way around that?
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      CommentAuthorSara 013
    • CommentTimeJun 25th 2010
     (8466.6)
    Inferring from the article / video, the Vet has been watching this (infection) closely.
    Since the tissue grew in /on / around the prosthetic, there was no infection.
    That's a tremendous benefit to this tech.
  7.  (8466.7)
    Since the tissue grew in /on / around the prosthetic, there was no infection

    I really want this to be true, but there's this nasty thing that happens with implanted metals, glass, and plastic that I'd be afraid of here; specifically, biofilms. These masses of bacterial goop like to form on nonbiological surfaces and they form a reservoir for infection. It's why implanted devices can be a health risk, even if they're totally contained inside the body. It's kind of awkward, and they like to talk about them at our lunchtime Infectious Disease lectures here at the hospital. Maybe I'm being too paranoid? Dunno.
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      CommentAuthorSara 013
    • CommentTimeJun 25th 2010
     (8466.8)
    With that specific article, lack of infection was fact.

    In general, yes, I understand your concern. You're definitely not being too paranoid. I avoid doctors & hospitals like the plague. .....heh.

    I don't claim to be an expert by any stretch of the imagination, but I sort of design / develop implantable metal and plastic devices for a living. Infection is always a risk, certainly. But with the proper materials, the proper design and the proper controls, that risk can be mitigated to such an extent that just entering a hospital poses more danger to you than actually having an implant. (It's possible that's a slight exaggeration, yes, but you get the idea ;) ) The particular products I work with promote thrombus build up, fibrogen formation, and eventually endothelialization - real, actual endothelialization, building the tissue layer upon layer at the cellular level, covering the entire metal structure, integrating it into the natural surrounding tissue - all of which starts immediately upon implantation and happens fairly quickly in the grand scheme of things (e.g. fully incorporated in six months). With this sort of healing mechanism, future infection becomes less and less of a potential hazard, based on what we've learned.

    And quite naturally, as with most things, it all depends upon what you're implanting and into whom you're placing the device.

    Circling back around to within the scope of this particular article, the advancements and technology presents some amazing possibilities.

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