anterior longitudinal ligament (cervical surgery question)

[rob_zzz]

Does anyone know anything about the anterior longitudinal ligament? I know it runs down the front of the spine (in front of the vertebrae). I'm wondering if its attached to each vertebral body. I assume it has to be cut during anterior surgery to get access to the disc space - is it removed or just cut open and then stitched (?) back together?

Or to summarise - during cervical disc replacement surgery - what is the effect on the anterior longitudinal ligament - is it removed, or just damaged but recovers? Is this different to what happens with fusion?

[mmglobal]

Yes, it's attached to each body.

Yes, it is cut during surgery.

Some doctors stitch the ALL and anterior annulus closed during lumbar ADR surgeries, but I don't recall seeing the flap saved in cervical surgeries.

With fusion you won't miss the ALL because the segment is no longer mobile. I don't know if you'll ever miss the ALL after ADR. I assume that it is redundant.

Mark

Hi Rob,

I asked my surgeon this, and according to him they cut like a little window in the ALL during ADR surgery.
The cut out material is not put back because ALL does not heal well at all (little blood supply was one reason he mentioned).
They window hole is insted overgrown with connective tissue (right word??) in time and it's not supposed to matter.

I have seen a cadaver spine and the ligaments are very, very closely connected with the spine. It's like a chain with shrinked plastic tube over it. Doesn't look very much like the anatomy books.
If you hold the length of a spine in your hands, it's very hard to bend it. The muscles help us with that.

[rob_zzz]

Thanks for the replies and the level of detail - very helpful.

I guess it might be something that might vary depending on the surgeon - I wonder how big the window hole they cut is compared to the size of that portion of the ligament.

Anyway - that sounds promising - if they only cut part of it out and then connective tissue grows back in there over time you would expect it to largely heal back similar in strength/function to what it was like prior to the surgery.

I asked the question because I'm still wondering about stability/strength of the cervical spine with the semi-constrained dish/trough disc designs on next extension.

Though just today reading through another aritcle I've got a better understanding of what the facet joints are now and I suspect these would create quite a lot of stability on their own during extension. (and then of course there's the muscles etc. - plus I've seen vids of the surgeries and it looks like a lot of work to prise apart the spine just to get the disc in, so you'd think it would take a pretty severe extension injury to disloge an ingrown disc).

[sahuaro]

As a result of your post (you ask the greatest questions), I googled ALL--and if I'm understanding some of the research papers, the ligament may already be damaged with degenerative disk disease, etc.

[paulam310]

Very interesting question, I'll have to ask my doctor the next time I see him. I know that in terms of muscular strength, I am stronger at my neck and around my neck than before surgery. I was lifting some weights today and I could tell that I am definitely in a better biomechanical postion. I think that as a result of my 3 level adr I will finally be able to develop some real muscular strength.

[rob_zzz]

I had another appointment with a neurosurgeon this afternoon and asked the same question. He confirmed that the ALL is removed during surgery but said that its not an issue from mechanical stability point of view. They try not to damage the posterior longitudinal ligament (which makes sense because the cord is behind it) - I also got the impression that the ligaments are more like a sheath that surround the front/back and sides of the vertebral column, so its more like (as KrisL said) taking a window out of the front - there's still ligament attached to the side and back of the vertebral body (was my understanding).

But the piece of ligament that is attached to the front of the vertebral bodies above and below the problem disc (i.e. the ALL) is removed during surgery, and then if I understood correctly he said scar tissue would typically form over that area.

In regards to my question about hyperextension he said that its more the muscles that would keep the spine in place (vs the ligaments), as well as the facets etc.

[sahuaro]

rob_zzz:
I am wondering how you are putting these pieces of information together, i.e., are your concerns about hyperextension allayed?

[rob_zzz]

I guess I'm still unsure. I've got a better understanding that there is quite a lot of stuff holding things in place - muscles, ligaments, facet joints etc. - but it sitll intuitively feels like there's a risk with the dish/trough design because the two vertebrae above and below the ADR aren't actually held together by anything, so I still don't really understand what would be keeping the neck together if someone was hanging upside down for example. (I guess the answer is that the muscles, ligaments, facets etc. would be keeping everything in place).

[mmglobal]

I've seen/held/examined the fibrous tissue that fills in the disc space after ADR surgery. It does not seem to have any structural integrity that would compensate for the loss of the ALL.

The ligament is redundant. If it wasn't... if you were at risk if you had a fender bender... widespread use of cervical ADR would not fly.

Mark