Tethering in skeletally mature people - data call

[Pooka1]

I'm actually curious. Is it common for rods to break before fusion is complete? My understanding is that you'd be talking about a 3-6 month window there, at least if you are talking about adolescents. Is that usually docs getting too aggressive and trying to straighten the spine more than they should?

Rods break because the fusion did not happen either in time before fatigue built up in the rod or at all. I think it is relatively rare in kids. I suspect virtually all cases are in adults.

In any event, I suspect you are probably right that broken tethers -- and they'll almost all probably break over the long term -- will result in the curves returning. I'm certain that I don't know you are wrong. As I said above, my guess is the docs tethering mature spines don't know either because they haven't been doing it long enough for significant numbers of their mature patients to have the tethers break.

Agreed.

[Concerneddad]

I think that's totally untrue with adults (and probably with most teens). Ask anyone who has had a broken rod prior to full fusion. Their curves usually return, especially if the implants are removed.

I'm actually curious. Is it common for rods to break before fusion is complete? My understanding is that you'd be talking about a 3-6 month window there, at least if you are talking about adolescents. Is that usually docs getting too aggressive and trying to straighten the spine more than they should?

In any event, I suspect you are probably right that broken tethers -- and they'll almost all probably break over the long term -- will result in the curves returning. I'm certain that I don't know you are wrong. As I said above, my guess is the docs tethering mature spines don't know either because they haven't been doing it long enough for significant numbers of their mature patients to have the tethers break.

[Pooka1]

If doing just discectomies or osteotomies with or without temporary support worked in adults I think we would know that by know.

[LindaRacine]

I've also known many teens who had excellent in brace correction, and who after maturity, had their curves return.

[LindaRacine]

The theory I've heard is that there is remodulation that occurs even in adults -- i.e., if you pull the spine straight for a long time, it will stay straight even if/when tethers break. I've seen the idea compared to adult braces (for teeth). I am completely unequipped to assess whether that is crazy or not.

I think that's totally untrue with adults (and probably with most teens). Ask anyone who has had a broken rod prior to full fusion. Their curves usually return, especially if the implants are removed.

[Pooka1]

The theory I've heard is that there is remodulation that occurs even in adults -- i.e., if you pull the spine straight for a long time, it will stay straight even if/when tethers break. I've seen the idea compared to adult braces (for teeth). I am completely unequipped to assess whether that is crazy or not.

Our orthodontist said if my girls didn't wear their retainers, the teeth might move back within a week. That is my memory though it was a long time ago.

They don't wear their retainers and their teeth look okay to me. They just turned 25 btw.

[Concerneddad]

As concerneddad says, discectomies do not require fusion. However, it makes no sense to me, to do a discectomy without fusion and implants in a mature adult. Movement (which is a given in discectomies without fusion and implant), is almost certainly going to result in an implant break when utilizing VBT implants in mature adults.

--Linda

The theory I've heard is that there is remodulation that occurs even in adults -- i.e., if you pull the spine straight for a long time, it will stay straight even if/when tethers break. I've seen the idea compared to adult braces (for teeth). I am completely unequipped to assess whether that is crazy or not.

[LindaRacine]

Can you give us your feel for the numbers?

If they do a discectomy they need to fuse the vertebra, no? I thought the point was to avoid fusion.

As concerneddad says, discectomies do not require fusion. However, it makes no sense to me, to do a discectomy without fusion and implants in a mature adult. Movement (which is a given in discectomies without fusion and implant), is almost certainly going to result in an implant break when utilizing VBT implants in mature adults.

--Linda

[Pooka1]

Thanks for that info, Concerneddad. I really appreciate your contributions to this forum. Thank you for that also.

DDD is as certain as death and taxes so unless the discectomies often or always result in fusions down the road, I don't think DDD is a reason not to do discectomies. There must be some data on this.

[Concerneddad]

Can you give us your feel for the numbers?

If they do a discectomy they need to fuse the vertebra, no? I thought the point was to avoid fusion.

Discectomies don't necessarily require fusion. Especially in the back with the bigger vertebrae, sometimes they can just remove the portion of the disc that is causing the pain (in cases of herniated discs), and then the remaining disc heals. (As opposed to the neck, where the discs are too small to do that, says the former C6-C7 herniated disc patient who still gets tingles and pain in his arm when he sits for too long.)

My (perhaps wrong!) understanding is that the doctors who are doing tethering surgeries on mature spines fall into two categories. Some only do it on super flexible curves that they can get really good correction on in the OR. A handful (a couple here, a couple in Europe) will cut into the disc to loosen it up and get near-perfect correction. I don't think they remove the whole disc -- they keep it in place and scar tissue forms. My main questions for the latter group of docs would be (1) does cutting into the disc put it at future risk of degenerative disc disease, and (2) what happens when a tether breaks, as it's almost sure to? The first question is mostly just a curiosity -- even a future risk of DDD is probably worth avoiding fusion, especially if we're talking L2-L4 -- but the latter is the real kicker. My guess is that they just don't know right now, because the surgery is new enough that they don't have a lot of patients who have reached the point where their tethers are breaking.

As far as numbers, my understanding is that dozens or hundreds of skeletally mature teenagers have been tethered, maybe a couple of dozen young adults (early 20s), and maybe a half dozen adult adults (including people in their 50s).

[Pooka1]

Can you give us your feel for the numbers?

If they do a discectomy they need to fuse the vertebra, no? I thought the point was to avoid fusion.

[burdle]

Thanks for this, Burdle. Can you post the FB page for people who want more information? I would have to search for it.

When you say quite a few, how many do you mean?

How many mature people have gone to Europe for tethering?

When you say the correction is done during surgery, do you mean osteotomies (cutting each vertebra)? If not then what exactly are they doing to correct the spine on the table?

Hi,

The link is https://www.facebook.com/groups/1121136701231861/ but it is a closed group. Look in the files section for info about European docs who do ASC. There is this link also to the UK site- a lot of people are members of both. You can get a feel for the numbers from there.


The spine has to be flexible and not degenerated for ASC on mature spines. but they tether the spine straight in the OR rather than expecting further growth modulation as in VBT on childre - hence the need for some flexibility. They sometimes do discectomy to achieve correction. There is a lot of detail in the files about discectomy as the disk is still preserved.

[Pooka1]

There are quite a few now who have been tethered. It is more 'skeltally mature' rather than 'adults' that is the consideration. The surgery is called ASC although strictly speaking the surgery done on immature spines is also ASC but is commonly referred to amongst patients at least as VBT. Both surgeries are done Anteriorly.

The difference is that with ASC the correction is done in sugery and the tether holds it whereas for VBT it is further growth of spine that enables a correction.

The FDA have approved the instumentation for VBT on paediatric patients but not so far on the skeletally mature. Quite a lot of patients go to Europe if they are mature.

Thanks for this, Burdle. Can you post the FB page for people who want more information? I would have to search for it.

When you say quite a few, how many do you mean?

How many mature people have gone to Europe for tethering?

When you say the correction is done during surgery, do you mean osteotomies (cutting each vertebra)? If not then what exactly are they doing to correct the spine on the table?

[burdle]

It is the exact opposite of seasoned. There may still only be a literal handful of adults that are tethered. The FB group would be able to tell you nearly exactly I suspect.

There are quite a few now who have been tethered. It is more 'skeltally mature' rather than 'adults' that is the consideration. The surgery is called ASC although strictly speaking the surgery done on immature spines is also ASC but is commonly referred to amongst patients at least as VBT. Both surgeries are done Anteriorly.

The difference is that with ASC the correction is done in sugery and the tether holds it whereas for VBT it is further growth of spine that enables a correction.

The FDA have approved the instumentation for VBT on paediatric patients but not so far on the skeletally mature. Quite a lot of patients go to Europe if they are mature.

[Pooka1]

It's not really a seasoned treatment for adults, is it?
Thanks for the facebook recommendation.

It is the exact opposite of seasoned. There may still only be a literal handful of adults that are tethered. The FB group would be able to tell you nearly exactly I suspect.