To me an internal bra procedure is an essential portion of a breast lift. This technique uses the tissue to hold up the result and not the skin. If the skin is of poor condition then it can not be expected to hold up the result long term.
To get a better answer to your question, you will need to clarify what you exactly mean by an "internal bra technique". I will assume you mean the use of a dermal matrix product to internally support an implant. I've used these technique for revisional breast implant procedures to control a pocket and/or correct severe bottoming. I have a good 3-4 years followup now and the results last. Its difficult for anyone to tell you the results will be permanent or will last 10, 20 yrs? We simply don't have the data. But frame your question with this: There is no anti-gravity procedure in plastic surgery - so results will evolve over time... Best wishes Dr. Basu Houston, TX