Expanders to Implants, nipple sparing 7.4 Square Tissue expanders are placed in the chest for a number of reasons at the time of double mastectomy. Tissue expanders are “filled” with saline gradually after mastectomy surgery. Usually every week or so, patients go in for a “fill.” Being gradual is more gentle on the healing tissue. Post op after nipple sparing double mastectomy drain holder around waist partially deflated tissue expander Tissue expanders are gradually filled until desired fullness is reached. A surgery is then scheduled to remove the expanders and have a permanent implant placed.