My left implant keeps breaking thru my skin. After 3 failed attempts and the last one with ADM. Any ideas why this is happening?

This is a very serious issue.  The soft tissue that normally helps support the impact sounds like it has failed and that ADM was used to help provide this support again.  This is a complicated problem that would require and in person consultation to review.  Consult the Smart Beauty Guide for surgeons in your area.

Why did your implant extrude?  And what does your surgeon think may have happened?  At this point, focus on healing and then if you feel implants are really important to you and your lifestyle, revisit the possibilities with your surgeon.  You may also consider getting a second opinion to verify what your surgeon tells you as I am skeptical that your graft was integrated 2 weeks out from its placement but I may be wrong.  The bottom line... when the procedures fail, you must figure out what happened before repeating the same 'mistake' to prevent it from happening again. 

First of all there is all the rage of going big when you have very little tissue.  All of my patients have this mentality of "go big or go home" or "bigger is better".  I try to teach my patients that going large will thin the tissue, have greater chance of rippling, capsule contracture and in certain cases implant erosion.  Obviously when you selected 600 cc this may not have been mentioned to you.  Or if it was you did not heed to the advice.  Thin breast tissue tends to have poor vascularity.  If you put an ADM device in and you have poor vascularity you are at greater chance to develop an infection. Implants do not simply extrude if there is no colonization by bacteria.  You must have had a biofilm develop and a breast capsule which in certain cases would cause tissue to thin if you wear bras that push too much in certain areas.  I've see many cases where the normal soft breast is OK with a push up bra but the one that has a capsule will progressively thin in the medial area of the breast.   I would try to do careful fat grafting to your breast first to increase the natural volume of the breast and then later use a smaller implant to achieve the look you desire.