A multi-lumen mold is for the in situ formation of a prosthesis in an annulus located in an intervertebral disc space of a patient. The annulus has at least two openings formed by minimally invasive techniques and at least a portion of the nucleus pulposus is removed to form a nuclear cavity. The multi-lumen mold includes a mold adapted to be located in the nuclear cavity. A first lumen having a distal end is fluidly coupled to a flexible mold at a first location. At least a second lumen having a distal end fluidly coupled to the flexible mold at a second location. The first and second lumens are adapted to extend out through the openings in the annulus when the mold is positioned in the nuclear cavity. One or more securing members can be used to secure the mold in the intervertebral disc space. The securing members can engage with the annulus, the end plates, and/or another surface of a vertebrate.