Directional tissue expander

With known mammary tissue expanders, as the inflation process continues, resistive pressure from the tissue on the anterior side of the expander can cause the expander to expand in undesired directions (i.e., axially and laterally). Thus, is would be desirable to provide an expandable mammary implant that better provides for the appropriate directional tissue expansion for any given size. An aspect of the invention includes an expandable mammary implant including a shell having an anterior face and a posterior face having a periphery. The anterior has an upper pole region and a lower pole region meeting at an apex, and an injection zone for receiving fluid therethrough to inflate the implant. A reinforcement material having (i) a peripheral rim portion that extends from the posterior face and (ii) an upper periphery. The first reinforcing material is coupled to the shell such that the first reinforcing material does not extend along the entire anterior face and at least a portion of the first reinforcing material has a lower elasticity proximal to the posterior face and a higher elasticity towards the upper periphery. A second reinforcing material is coupled to the shell and extending along a portion of the anterior face of the shell. The first reinforcing material overlaps or abuts the second reinforcing material at or adjacent the upper periphery of the first reinforcing material in the upper pole region wherein a portion of the lower pole region is not reinforced by either the first or second reinforcing material. The reinforcement zone covers the upper pole and a peripheral zone extending from the peripheral rim of the posterior face into the anterior face such that upon inflation, expansion of the implant occurs disproportionately in the lower pole region.