A method of positioning an S-shaped tool against inner annular walls of the disc that particularly facilitates reaching posterior and postero-lateral portions of the inner annulus of the disc by arthroscopy. An elongated, arcuate and S-shaped tool such as a catheter is positioned against the inner annular wall of the disc, and particularly on the posterior and postero-lateral portions of the inner annulus of the disc, which are portions of the disc to be treated. The deformable, arcuate and S-shaped tool retains its predetermined arcuate, S-shape when no pressure or force is applied to the tool.