A prosthetic duct system comprising: an expandable main duct (20) having a first open end (22), a second open end (24), a main duct wall extending between them, a surface (21) of outer duct, and an inner duct surface (23), at least the expandable main duct (20) having an opening (60) through the main duct wall, and an inner duct (54) having an inner surface, an outer surface, a first open end (56) located within the main duct (20) and a second open end (58) in the opening (60) in the wall of the main duct； an expandable secondary conduit (26) having a first open end (27), a second open end (29), a secondary wall (31) extending between them, and a fixing part (36) extending forming a angle of less than 90 degrees relative to the secondary wall (31) when in an unfolded state； at least a part of the secondary conduit (26) being sized to pass through the internal channel (54) of the main conduit (20) and through the opening (60) in the wall of the main conduit, and the fixing part being configured (36) to be applied and / or blocked on the first open end (56) of the inner channel (54).Un sistema de conducto protésico que comprende: un conducto principal expandible (20) que tiene un primer extremo abierto (22), un segundo extremo abierto (24), una pared de conducto principal que se extiende entre ellos, una superficie (21) de conducto exterior, y una superficie (23) de conducto interior, teniendo al menos el conducto principal expandible (20) una abertura (60) a través de la pared del conducto principal, y un canal interno (54) que tiene una superficie interior, una superficie exterior, un primer extremo abierto (56) situado dentro del conducto principal (20) y un segundo extremo abierto (58) en la abertura (60) en la pared del conducto principal； un conducto secundario expandible (26) que tiene un primer extremo abierto (27), un segundo extremo abierto (29), una pared secundaria (31) que se extiende entre ellos, y una parte de fijación (36) que se extiende formando un á
