What are the risks of Fat embolism, pulmonary embolism, and non-union with exter

Naturally, most of the posts here these days are in relation to internal lengthening methods, but I’m wondering what the comparative risk of the most serious complications is for fully external vs newer methods.

Infection risks aside as that has been well documented–and also putting aside the analysis of the pros and cons of each lengthening method as a whole as I don’t want the thread derailed–I’m interested in the following:

Fat embolism: I would assume the risk is very small. As far as I’m aware, the fat embolism risk comes with reaming the bone thus moving droplets of fat into the bloodstream, which wouldn’t be happening with externals.

Pulmonary embolism: I’m not sure I even fully understand what causes this in the first place, and to what extent the risks can be mitigated by medication. I’m guessing that most of the risk is post-operatively rather than intra-operatively? 
I think I read somewhere that tibial lengthening has a lesser risk than femoral naturally, regardless of internal vs external, because there's less of a propensity for a clot to travel dangerously to the heart or brain, but is there a difference in risk attributed to the external frames alone?

Non-Union: I think I'd say this is my biggest fear with limb lengthening, and I know the tibias come with a slightly higher risk with this as well. I've browsed some old posts here about non-union, and I know there is a list of known risk factors like smoking and lengthening rate, but what is the likelihood of this actually occurring when you don't have any of those factors at play?

I assume that a lot of the people who get it regardless have some sort of pre-existing bone-forming condition. I guess these same people would have a similar problem if they broke a bone naturally. I've heard scary stuff about potentially having to have the leg amputated/have a permanent disability, but if the worst came to the worst with external frames, couldn't you just reverse the frame so that the bones met again?

Thanks!

Chance of fat embolism is very very low. Even more so with a good surgeon who knows how to do the reaming properly.

Pulmonary embolism can come from blood clots. They can dislodge (usually from the legs) and travel up to the lungs. You’ll be prescribed a blood thinner like Xarelto which minimizes this risk. Walking and not just lying in bed all day is a must to prevent blood clots. People with weight bearing nails almost never have this issue since they can walk.

Non Union is also rare. A good surgeon should catch this early and prevent you from lengthening too much if you’re in danger of having this. One thing to note here is that the current set of weight bearing nails (like Betzbone and G-Nail) cannot go backwards, but Precice can! So with Precice if you’re in danger of getting non-union they can fix it by reversing the lengthening a bit and waiting for the bone to form. The other nails cannot do this.

Quote from: GrowGrow123 on August 20, 2023, 08:05:27 PMChance of fat embolism is very very low. Even more so with a good surgeon who knows how to do the reaming properly.

Pulmonary embolism can come from blood clots. They can dislodge (usually from the legs) and travel up to the lungs. You’ll be prescribed a blood thinner like Xarelto which minimizes this risk. Walking and not just lying in bed all day is a must to prevent blood clots. People with weight bearing nails almost never have this issue since they can walk.

Non Union is also rare. A good surgeon should catch this early and prevent you from lengthening too much if you’re in danger of having this. One thing to note here is that the current set of weight bearing nails (like Betzbone and G-Nail) cannot go backwards, but Precice can! So with Precice if you’re in danger of getting non-union they can fix it by reversing the lengthening a bit and waiting for the bone to form. The other nails cannot do this.

What exactly is the difference between fat embolsim and pulmonary embolism?

From what I understand fat embolism is caused by bone marrow fat entering the blood stream in connection with internal lengthening devices. And from what I understand some fat is unavoidable but the important thing is that it doesnt happen too much to cause a stroke if the fat enters the heart.

From what I understand pulmonary embolism is caused by a blood clot in the lungs, but is it correctly understood that this is also caused by the fat from the bone marrow when using internal methods?

As in, is the only difference between fat embolism and pulmonary embolism whether the blood clot happens in the heart or in the lungs?

Yes a pulmonary embolism just means an embolism of the lungs. Whether it’s caused by blood clot or fat. Though people will usually refer to it as a fat embolism if it’s caused by fat / marrow to differentiate it.

A fat embolisms could effect other organs in the body, but generally the issue is with getting the emboli in your lungs as a limb lengthening patient. This can cause you to essentially suffocate and die. Fat embolisms are mitigated by only doing a single segment at a time, such as doing tibias then waiting approximately 3 weeks until doing the femurs. Additionally, fat embolisms are mitigated by venting the bone prior to inserting the nail. This allows the bone marrow(fat) to escape the bone rather than being pushed into your circulatory system where it can get trapped in places such as your lungs and suffocate you. Another way fat embolisms are mitigated are by monitoring your O2 and heart throughout the procedure. If you go to a reputable surgeon, in my opinion, this isn't a big worry.

Also, fat embolisms can happen quite easily and often. It's the extent to which that makes it a problem. How much is getting into your bloodstream?

"Fat embolization occurs frequently following orthopedic trauma. Fat globules have been detected in the blood of 67% of orthopedic trauma patients in one study.[5] This number increased to 95% when the blood is sampled in close proximity to the fracture site."[6]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665122/

https://my.clevelandclinic.org/health/diseases/23995-fat-embolism-syndrome


Pulmonary embolisms are the worst complication a patient could experience, yet the rarest. It cannot be understated how exceptionally rare they are, but it is fair and honest to talk about it because it can happen and it can kill you. They are easy to mitigate, with doctors prescribing anticoagulants as a prophylactic measure. Getting active as soon as possible is also key, which is why Doctor's often have weight bearing patients walk the same day or day after, and non-weight bearing patients begin their PT/stretching as soon as possible. The risk is incredibly small, but if it happens, you could die without medical intervention. We often hear about patients getting butchered in Turkey with non-unions, nerve damage, or other complications, but hearing of a pulmonary embolism even from Turkey is almost unheard of. I could list a few members here on this forum and from YouTube who were butchered, but none that died. It's rare.

https://www.mayoclinic.org/diseases-conditions/pulmonary-embolism/symptoms-causes/syc-20354647

https://www.medicalnewstoday.com/articles/pulmonary-embolism-after-surgery#prevention

https://limblengthening.org/complications/

Prior to developing a pulmonary embolism, one needs to develop deep vein thrombosis(DVT). Just because you have DVT, does not mean you will have a pulmonary embolism, and the risk is still quite small, but it could happen. Additionally, just because you get a pulmonary embolism after DVT, does not mean you will die as it can be treated, but if it's not treated you absolutely can.

"Among patients presenting with DVT, the rate of fatal PE during anticoagulant therapy was 0.4% (95% confidence interval [CI], 0.2%-0.6%); following anticoagulant therapy it was 0.3 per 100 patient-years (95% CI, 0.1-0.8 ). The case-fatality rate of recurrent DVT or PE during anticoagulant therapy was 8.8% (95% CI, 5.0%-14.1%); following anticoagulant therapy it was 5.1% (95% CI, 1.4%-12.5%). Among patients presenting with PE, the rate of fatal PE during anticoagulant therapy was 1.5% (95% CI, 0.9%-2.2%); following anticoagulant therapy it was 0 per 265 patient-years (95% CI, 0-3.6). The case-fatality rate of recurrent DVT or PE among patients presenting with PE was 26.4% (95% CI, 16.7%-38.1%). "

https://pubmed.ncbi.nlm.nih.gov/9466640/

It's important to note that the study is not showing specifically limb lengthening patients, but I do not believe limb lengthening patients are at risk of recurrent DVT or PE since this procedure is a "one and done" sorta thing. If you are a patient with some kind of chronic disease, then you are at a far greater risk than a LL patient. Feel free to correct me on this, but I see no evidence or logic to the contrary.

TL;DR

Embolisms, fat or pulmonary, are exceptionally rare. I wouldn't worry about it, but informed consent is important. Pick a reputable surgeon and you'll be fine.

All of these are risks for sure

Thanks to all of you for such well-developed explanations and for sharing all these articles, knowledge is gold and the best weapon to face barbaric procedures like this 

Thank you for sharing the detailed information.