Prosthetic nucleus apparatus and methods for treating an intervertebral disc are disclosed. Prosthetic nucleus apparatus may include a barrier sealant membrane and a prosthetic nucleus material. The barrier sealant membrane forms a chamber which can receive the prosthetic nucleus material. The barrier sealant membrane can be formed by depositing a layer of material on a tissue surface within a de-nucleated space within an intervertebral disc. The prosthetic nucleus material may be positioned within the chamber of the barrier sealant membrane after the barrier sealant membrane is deposited within the de-nucleated space. The barrier sealant membrane and the prosthetic nucleus material may be positioned within a patient through an axial trans-sacral bore. A plug may also be included to prevent expulsion of the barrier sealant membrane and prosthetic nucleus material.