I have used nearly all of the acellular dermal matrices (e.g., FlexHD, AlloDerm, AlloMax, etc.) I have found excellent results with the FlexHD and AlloMax. FlexHD by Mentor is truly a fabulous product with great advantages. The use of the acellular dermal matrix has grown in its applications and use in plastic & reconstructive procedures, and growing. It has truly been a remarkable addition for breast reconstruction.
The acellular dermal matrix is a tissue that is specially-prepared, which comes from cadaveric skin. It is placed on the inside, not on your skin. It has been processed in such a way that the basement membrane and cellular matrix remain intact, while removing all other cellular components that may lead to both rejection and infection. Packages as a sterile tissue product, due to its preparation, the chance of acquiring viruses and such is nearly absent.
Its applications for breast reconstruction alone include its use in tissue expander/implant reconstruction, to act as a "hammock" at the inferior portion of the breast for which the implant lies within. This creates a natural "sling" which mimics the ptosis (sag) of the breast, while supporting it in place. By suturing this matrix to its exact position of the breast margins, the plastic surgeon is able to precisely recreate an excellent contour for your breast, especially at the inferior, medial, and lateral positions. This also minimizes migration of the implant, as sometimes seen with "bottoming out" inferiorly or its displacement into the axilla (armpit). In addition to its increased aesthetic results, the acellular dermal matrix provides additional coverage over your implant. This is especially useful in those instances of dehiscence (your incision opening up), thus protecting the implant from exposure, and threatening its necessity for removal. Furthermore, in cases where the overlying mastectomy flaps are thin or damaged, leading to partial flap necrosis, the tissue matrix again provides a coverage over your implant, which can heal over time or a graft placed over the are or simply closed. Lastly, the additional coverage lessens implant visibility and palpability and is a great adjunct for revisionary breast surgery. The use of this matrix, along with the advantages listed above, has reduced the time of the reconstructive portion of the procedure as well. There is less pectoralis muscle retraction and eliminates the need to raise any other surrounding muscles in order to achieve complete implant coverage. Much is surgeon preference.