Small to meduim sized unptotic breast can be reconstructed simultaneously with breast removal in one operation if nipple sparing mastectomy is performed.
Single stage reconstruction can be performed with autologous tissue or more commonly with implants- direct to implant reconstruction. Using implants requires additional reinforcement (like internal bra) in the form of mesh or ADM (acellular dermal marix) which covers the implant and stabilizes it in the correct position. Implants are usually put under the pectoralis major muscle or with sufficent thicknes of subcutaneus tissues over the muscle. The term "single stage" is somehow misleading since almost always additional procedures (e.g. fat grafting) are necessary to improve the results.