
Direct vascular channels connect skull to dura, enabling myeloid cell migration - bookofjoe
https://www.nature.com/articles/s41593-018-0213-2
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annamargot
Are these vascular channels like tiny veins?

Would such things be severed if someone were to have a craniotomy / brain
surgery during which a piece of skull is temporarily removed for access?

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bookofjoe
Yes, they would be severed in such a case. I am a retired neurosurgical
anesthesiologist.

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annamargot
Would they regenerate after the skull was put back in place?

Are there other connections -such as the recently discovered lymphatic vessels
- that are severed during craniotomies?

[https://www.theatlantic.com/health/archive/2017/10/scientist...](https://www.theatlantic.com/health/archive/2017/10/scientists-
somehow-just-discovered-a-new-system-of-vessels-in-our-brains/542037/)

I guess the bigger question I have is what are the repercussions/downsides of
removing large portions of the skull temporarily?

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bookofjoe
>Would they regenerate after the skull was put back in place? I had EXACTLY
that question after responding to your earlier comment. My best guess: I think
they would regenerate. But I suspect that would depend on the age of the
patient, with regeneration capability (if it exists) decreasing with age. >Are
there other connections -such as the recently discovered lymphatic vessels -
that are severed during craniotomies? I hadn't seen the Atlantic piece so I
read it carefully. The article's writer (not the scientist he interviewed)
wrote "The lymph vessels probably escaped detection because they're inside a
thick membrane, the dura mater, which is the consistency of leather. They run
alongside blood vessels that are much larger, and on MRI the signal that
creates the images is dominated by the blood vessels." Reading that, I thought
that these newly discovered lymphatic vessels were not connected at all to the
skull. But further along in the article: "It now seems clear that there is a
third pathway through which byproducts get out of the brain — and it may be
the most important — through these specialized vessels in the dura
mater.'Looking back, those other two really seem insufficient,' said Reich."
Reich is the lead scientist whose paper is cited in the Atlantic article.
Since the skull-dura connections just discovered and described in my OP had
not, as far as I can tell, been known previously (i.e., in 2017 when Reich's
paper appeared), I'd have to again plead uncertainty and ignorance. Lymphatic
connections between bone and dura — or between bone and any other structure in
the body — that's outside my knowledge and expertise. >I guess the bigger
question I have is what are the repercussions/downsides of removing large
portions of the skull temporarily? It's been done since Pharaonic-era Egypt,
without apparent repercussions/downsides. In my experience of having
anesthetized patients for an estimated 500-1,000 craniotomies with bone flap
removal over 38 years of practice, I can't say I've ever noticed problems
(other than post-op infection or CSF leakage). Consider also that many
patients never have the bone flap replaced but instead have a metal plate
applied over the opening in the skull, which they then live with without
apparent sequelae (other than TSA kerfuffles when the airport metal detector
goes berserk) for the rest of their lives.

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annamargot
Thank you. Very interesting.

Might be interesting to see if patients who’ve had a craniotomy (of some
threshold of size) have greater neuro-related issues in their future.

Do they have less capacity to inhibit inflammation, etc.

I suppose the bias would be heavy, since there’s prob something troubling
happening in the first place if they’re cutting open your skull. :)

