3 ms·

Actually the DBS implants for Parkinson's disease are relatively safe, and are being used more and more often, frequently to correct adverse effects from medica

by caycep 13y ago

Actually the DBS implants for Parkinson's disease are relatively safe, and are being used more and more often, frequently to correct adverse effects from medications...it's about a 1-2% chance of a minor hemorrhage with infection rates differing among centers. The VA had something terrible, like 9% but the series out of UCSF did better. These are all treatable, or at worst, you just remove the device. In terms of removal, it's actually easier with age, for some odd reason. Surgeons report that after a few years, they slide out. A lot of handwaving as to why, but some thought is that there's some sort of encapsulation layer that builds between the surface and the neural tissue, or some layer of fluid space or whatnot. It's a matter of perfecting the tech. The experimental BCI stuff - i.e. Utah arrays, are still externalized and are risky, and yes they do have a ways to go before ready for population-wide deployment..

malandrew 13y ago
How complex is the surgery for these? For example, do we already have some sort of skull/brain endoscope whereby you drill a little whole and do the surgery by wire, or do you still have to open up the skull to install the implants?
- caycep 13y ago
  It's not too bad. More like the "brain endoscope" route, except it's just a think micro electrode to confirm the target, then the actual wire itself. Nothing optical (although our surgeon does use an optical endoscope for a different type of surgery, pituitary tumor removal). Pretty standard stereotactic stuff - metal rigid frame (google Leksell or CRW/Luminant for examples) gets bolted into the outermost bone layer (w/ local anesthesia) that puts the head into an XYZ cartesian coordinate system. The complex stuff is the planning - MRI images have to be taken w/ the frame on, and there's some linear image registration that happens via software. Once the surgeon plans the trajectory (basically a straight line to the targeted brain structure), it's relatively easy - the incision/craniotomy is basically a ~1 cm or less burr hole drilled into the skull, and a micro drive advances first a micro electrode (for confirmation via single unit nerve firing recordings every ~ 0.5 mm or so), then the actual electrode, which is a little over 1 mm in diameter. The surgeon may adjust the trajectory by a few mm either way if he decides he doesn't like the recordings along the length of the trajectory. The battery/onboard electronics is in a pacemaker-like device that is just put in under the skin in the chest...the tunneling of the wire from the skull to to chest is arguably the hardest part surgically. Epilepsy brain mapping, on the other hand, is a whole lot more complex, with much more signals processing and data acquisition involved (a bunch of 8x8, 16x16 or more grids of ~ 0.5-1cm electrodes recording local field potentials, and a open craniotomy where you take off a large chunk of skull)
  - dm2 13y ago
    Are the power and electronics embedded in the skin for a specific reason? I would much rather have a plug in my head and have all of the electronics and battery external. I would want a flesh colors cap for the plug for when it's unplugged, don't want anyone trying to plug headphones into me.
    - caycep 13y ago
      infection and wound healing. Breaks in the skin are always a huge infection risk, compounded by the fact that implanted hardware is always an infection risk, especially ones that are exposed. The reason being that implants do not have convenient blood vessels coursing through them like us meat bags, and thus the white blood cells that fight infection can't really clear any bacteria that happens to stick onto the surface of these things. Keeping things under the skin solves a lot of these problems. The experimental Utah arrays with the Braingate consortium are in fact externalized, (mostly due to bandwidth limitations of the hardware) and managing those folks are pretty tricky. A port would be nice - I think a more pressing need for "ports" would be the critical care and oncology (cancer) folks - patients who need to provide access to the bloodstream. Central lines, dialysis fistulas, chemotherapy ports are all notorious for getting infection. We're not talking about a minor infection of a cut, say, but serious risks like abcesses and sepsis and meningitis here (especially re brain implants who cross the meninges and into brainspace...don't want bacteria happily munching away there...) That being said, the next evolution of the brain-machine interfaces that use high-bandwith data and power transfer to get around the whole pesky skin issue.

by caycep 13y ago

malandrew 13y ago

How complex is the surgery for these? For example, do we already have some sort of skull/brain endoscope whereby you drill a little whole and do the surgery by wire, or do you still have to open up the skull to install the implants?

caycep 13y ago
It's not too bad. More like the "brain endoscope" route, except it's just a think micro electrode to confirm the target, then the actual wire itself. Nothing optical (although our surgeon does use an optical endoscope for a different type of surgery, pituitary tumor removal). Pretty standard stereotactic stuff - metal rigid frame (google Leksell or CRW/Luminant for examples) gets bolted into the outermost bone layer (w/ local anesthesia) that puts the head into an XYZ cartesian coordinate system. The complex stuff is the planning - MRI images have to be taken w/ the frame on, and there's some linear image registration that happens via software. Once the surgeon plans the trajectory (basically a straight line to the targeted brain structure), it's relatively easy - the incision/craniotomy is basically a ~1 cm or less burr hole drilled into the skull, and a micro drive advances first a micro electrode (for confirmation via single unit nerve firing recordings every ~ 0.5 mm or so), then the actual electrode, which is a little over 1 mm in diameter. The surgeon may adjust the trajectory by a few mm either way if he decides he doesn't like the recordings along the length of the trajectory. The battery/onboard electronics is in a pacemaker-like device that is just put in under the skin in the chest...the tunneling of the wire from the skull to to chest is arguably the hardest part surgically. Epilepsy brain mapping, on the other hand, is a whole lot more complex, with much more signals processing and data acquisition involved (a bunch of 8x8, 16x16 or more grids of ~ 0.5-1cm electrodes recording local field potentials, and a open craniotomy where you take off a large chunk of skull)
- dm2 13y ago
  Are the power and electronics embedded in the skin for a specific reason? I would much rather have a plug in my head and have all of the electronics and battery external. I would want a flesh colors cap for the plug for when it's unplugged, don't want anyone trying to plug headphones into me.
  - caycep 13y ago
    infection and wound healing. Breaks in the skin are always a huge infection risk, compounded by the fact that implanted hardware is always an infection risk, especially ones that are exposed. The reason being that implants do not have convenient blood vessels coursing through them like us meat bags, and thus the white blood cells that fight infection can't really clear any bacteria that happens to stick onto the surface of these things. Keeping things under the skin solves a lot of these problems. The experimental Utah arrays with the Braingate consortium are in fact externalized, (mostly due to bandwidth limitations of the hardware) and managing those folks are pretty tricky. A port would be nice - I think a more pressing need for "ports" would be the critical care and oncology (cancer) folks - patients who need to provide access to the bloodstream. Central lines, dialysis fistulas, chemotherapy ports are all notorious for getting infection. We're not talking about a minor infection of a cut, say, but serious risks like abcesses and sepsis and meningitis here (especially re brain implants who cross the meninges and into brainspace...don't want bacteria happily munching away there...) That being said, the next evolution of the brain-machine interfaces that use high-bandwith data and power transfer to get around the whole pesky skin issue.