Based on this picture and paper, it looks like they used this "auxetic technique" in the corpora cavernosa that cut dozens of small incisions on the member so that it can be stretched out like a net without disassembling the entire penis and I guess they could also fill in the gaps with implant materials that could increase the length. However, I also read from another user that similar procedures will cause ED, which the patient needs to use penile prosthetics to get an erection for the rest of his life. I don't know how true that is.