A minimally invasive medical device for tissue expansion is provided. The medical device has an expandable balloon and a sturdy substantially hollowed core. A membrane-covered port is provided at one end of the balloon to receive an insertion apparatus or an injection member. The balloon is inflatable by injecting a gas or a liquid through the membrane-covered port via the insertion apparatus or the injection member. A shell is provided to substantially encase the balloon and the insertion apparatus is provided to assist with maneuverability of the medical device. A method of tissue expansion includes implanting the medical device into an expandable tissue and inflating the balloon. A method of expanding a breast tissue of a patient after a mastectomy includes placing a patient under local anesthesia, making a small incision into an expandable tissue, implanting the minimally invasive medical device, and inflating the device gradually.
