I believe surgeon comoet3nncy along with your own bodies response have a lot to do with the outcome.
First two surgeries with rahal most my hearts fell out by three weeks, and by the fourth was all out.
Third procedure with a Turkish surgeon known as ekrem give, and I would say 50% of the hearts continues to grow, while the remaining fell out. Surprisingly enough, almost all the hearts remained at the hairline, while the rest fell out.
Prior surgeries all addressed the frontal third.
From my exp3rienc3 I believe graft handling and placement latterly determines whether you shed or not. Seeing how my first two procedures I shed everything, while the third I kept a large amount. However the templ3 points all shed in every surgery.