One thing that I'd be concerned about for clavicle lengthening is doctor experience. There would be even less studies out there about long term effects of clavicle lengthening then there are for leg lengthening. I'm not sure even Dr Paley lengthens them.
I would be very concerned as well, there is only one report on clavicle lengthening via a distraction device. It has been done for medical reasons and seemed to be a success, what speaks for lengthening the clavicle is that there doesn't seem to be much soft tissue attached to it.
As we all know, when lengthening the bone itself really isn't the bigger problem but rather the muscles, nerves and tendons around it. When lengthening the clavicle this could be much less of a problem, however like KiloKahn says the main issue is that it just hasn't been done cosmetically before -at least not that I know of.
Longer clavicles would give two important benefits for us LL patients it would:
-Improve proportions drastically as it makes our wingspans fit our new height and accentuates our torsos rather than our lengthened legs.
-Improve balance by making us broader, this is important now that we will become taller.
In the study average length gained was 31mm but since he patients had abnormally short clavicles to begin with this represented an increase of about 25% on average. Assuming we cosmetic patients are a bit more conservative we migt aim for a 10% increase which in my case would be around 4-5CM. That may not sound as much but when it comes to shoulder width it will be a
massive difference.
I'd be very interested to learn more about this, especially since I myself could benefit greatly from broader shoulders, if anyone is in contact with a trustworthy surgeon know that it would be greatly appreciated if you ask him about it.