An axillary incision is similar to a peri-areolar or IMF incision in that you can do the initial augmentation though the incision and exchange implants through the incision. It is a common myth that silicone and large implants cannot be placed through an axillary incision, both of those are not true. I routinely place large silicone implants through an axillary incision.
Women many times decide they would like to change the size of their implants for whatever reason. This can easily be done through the axillary incision. With the use of the endoscope and specialized equipment the implant can be removed, the pocket adjusted and the new implant placed with the use of the Keller funnel.
Please be sure to consult with your board certified plastic surgeon.