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-syndromePulmonary 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-20354647https://www.medicalnewstoday.com/articles/pulmonary-embolism-after-surgery#preventionhttps://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.