A tissue expander is inserted under the breast muscle and the surrounding muscles with its valve above the existing scar and is filled up over the course of several weeks with salt solution by injection through the valve. As the expander is filled, the soft tissue above it expands. Once the skin and muscle have expanded sufficiently, after about 6 months, the tissue expander is removed through the existing scar and replaced with a silicon gel implant of corresponding size. The great advantage of this procedure is its simplicity. It is a relatively simple surgical procedure, which above all does not cause any additional scarring. Furthermore, there is always the possibility of carrying out a more complex reconstruction at a later date.

The most serious disadvantage of this procedure is that the body always recognises the silicon gel implant as a foreign body and forms a coating of connective tissue around the implant. If the coating shrinks or hardens, a capsule fibrosis forms. For the patient this means the hardening of the reconstructed breast and dislocation of the implant. Without therapy and if the fibrosis continues to develop, there will be a range of possible consequences, from pain and alterations in the skin to perforation of the implant by the skin. A further disadvantage is the greater firmness and stability of shape of such a reconstituted breast, in contrast to the retained soft, less rigidly positioned, contralateral breast. Despite having the same volume, a clear difference remains between the two sides, which increases with age. The impaired micro-circulation in the skin after radiotherapy leads to a much higher rate of complications for tissue expansion and the insertion of silicon gel implants, and for this reason this procedure should no longer be carried out after radiotherapy.

The use of textured, anatomically shaped, silicon implants filled with cohesive gel has led to a significant improvement in the results of reconstruction with this procedure. The concerns still sometimes voiced today regarding the teratogenicity or mutagenicity of silicon gel implants or a possible relationship to autoimmune diseases are without any scientific basis at all. The main advantages and disadvantages of breast reconstruction with tissue expanders and silicon gel implants are summarised in Table 1.