A device to be implanted in a subject's body to form an implant for replacing and/or increasing a volume of soft tissue, the device being of the type including a three-dimensional frame which defines an inner space in the frame. The frame is typically bio-absorbable and includes two side apertures forming a transverse passage for inserting a vascular pedicle. The device further has at least two bio-absorbable textile sheets that can be stacked on each other in the inner space of the frame.