Never heard of the lamellar split osteotomy, but you'd expect there must be a reason that it is not used a lot.
All in all there is a lot of discussion about the zygomatic osteotomy on the forum, but having read the forum: very few members seem to actually have gotten a zygomatic (sandwich) osteotomy. And the discussion in general seems to be 'I might get a zso too, to get high cheekbones like male models have', etc. I have written my thoughts about that, but I really feel these type of comments are open to a gross misrepresentation of what a zso can do. The very few members that I did read that got a zygomatic sandwich osteotomy either were posting at 3-6 weeks post-op, when there is still heaps of diffuse swelling that augments the cheekbones. Ncharm is actually one of the only/very few other members I have seen here that is longer out of surgery, and she has written too that she mostly got some projection at a lower level.
As to the result: I estimate there is 2 cm of flatness laterally from the canthus and underneath the canthus, then there is the step off (although not visible given the limited augmentation) and then you have the augmented area. And that is a minor part of the lower zygomatic arch, as mentioned: some fullness at the lower cheek. There is no tapering of course: the area above the fractured bone segment is flat, and then there is the step off to the area that is slightly augmented. And that slight augmentation comes from a small portion of your lower zygomatic bone that is pushed outwards.
I feel these zygomatic osteotomies are massive surgery with unimpressive results. You are not looking at a few weeks of swelling but months and months of diffuse swelling, mostly lingering around the cheeks. A girl that was worried about over-augmentation a few weeks after surgery when getting an osteotomy apparently was told by the surgeon that at 3 months there would only be a subtle change compared to her pre-surgery face. And although 3 months seems a bit optimistic, in general that is what I feel too: you will undergo massive surgery, have swelling for months (which is hard to distinguish from your own tissues once the very visible bulk of swelling is gone), and you end up with a minimal change. (And if you are out of luck and a bit older with less elastic tissues, you risk ending up with some soft tissue changes because of the continuous swelling and minimal change).
I expect this is different when the malars up until the inferior orbital rim are fractured, since obviously you will have a good amount of bone that is fractured and thus more augmentation. Moreover the upper part of the zygo bone gets augmented too this way, so it is expected the procedure might result in that high cheekbone. But I'm still not completely convinced of any zygomatic osteotomy, until I really see a good result first-hand a lot of time after the actual surgery. Concerning the Lefort III: I saw some very small pictures of that member Earl after he got a modified Lefort III and he did seem to have gotten good augmentation, high on the zygo bone, but I don't know how much swelling was still there. Still these surgeries that involve a bigger part of the zygo bone obviously yield more dramatic results.
I do really understand now why it is often de-recommended by surgeons to get a zygomatic (sandwich) osteotomy. I have read the comments that those surgeons that de-recommend to get zygo osteotomies can't perform an osteotomy, and that might be right. However I consulted with both craniofacial and craniofacial plastic surgeons, and I was warned to not get a zygomatic osteotomy. The long downtime was what I was warned for and the unimpressive results. These surgeons could perform both a zygomatic (sandwich) osteotomy and insert an implant, and had done a lot of both, and they picked the implant. The info I got was that they could not let a patient undergo such a massive operation with such a long downtime, swelling for up until a year until the final result is visible, and a mediocre result, when there is a procedure available that gives aesthetically better, more predictable results with far less downtime. Either way: many voices, many visions and I picked differently.
However I have my reservations.
The lefort's, bsso's, etc: these surgeries can bring about dramatic changes that are not comparable to most plastic surgery results. That I can see. The sliding genio can look nice. But some folks seem deadset on augmenting every part of their faces through osteotomies, convinced their own bone can be manipulated in such ways that with a simple 'cut and paste'-surgery involving the mandible or zygo's you can alter your own bone structure dramatically. Whereas in reality the surgeon has to work with your own bone with all its limitations, can only make limited cuts because of nerves and the surgery can give limited augmentation, existing assymetry will become more apparent most of the times, often bone needs to be grafted, there can be some bone resorption etc. And that aside you will be undergoing massive surgery with a long downtime, and it will take a long long time before you will see the results that are often not as dramatic as with implant surgery. I sometimes see suggested here to then get an osteotomy twice to get more augmentation similar to what an implant could give. Twice?
Make that three times if you need a revision of one of those two surgeries. I then read to get the jaw shaved in Asia since the chin wing procedure might give an U-shape to the mandible instead of the often more desirable V-shape. Overall all this just confirms that the results of these osteotomies (lefort's, bsso's etc aside, and I think the sliding genio can also yield nice results) are not as impressive as we'd want them to be, have a lot of limitations (after all: you can not really prevent getting a U-shaped mandible after a chin wing), and require further massive surgery if you'd want to get a more optimal result or a result as drastic as implant surgery might give.
And these are massive/drastic surgeries, with a long downtime (you might as well add all the travel costs/downtime in which you might not be able to work to the costs of surgery, not to mention missing out on socializing for a good while). Getting some cheek fillers gives a much more predictable result, and the downtime is zero.
Either way, if I see someone post pictures from zso's performed by Mommaerts in which the patients are 6 weeks out of surgery, I cringe. This is massive surgery and swelling is lingering all over the face for months and months. What you are looking at at 6 weeks is augmentation caused by swelling.