the intervertebral disc is avascular . with aging , endplates become occluded by calcified layers , and diffusion of nutrients and oxygen into the disc diminishes . the disc degenerates , and pain ensues . conduits are delivered and deployed into the intervertebral disc to re - establish the exchange of nutrients and waste between the disc and bodily circulation to stop or reverse disc degeneration and relieve pain . the intervertebral disc installed with semi - permeable conduits may be used as an immuno - isolated capsule to encapsulate donor cells capable of biosynthesizing therapeutic molecules . the semi - permeable conduits establish the exchange of nutrients and therapeutic molecules between disc and bodily circulation to treat a disease without using immuno - suppressive drugs .