An externally guidable intervertebral disc apparatus manipulates tissue at a selected location of an intervertebral disc. The apparatus comprises a catheter having a distal end, a proximal end and a longitudinal axis, the catheter having an intradiscal section at the distal end of the catheter, the intradiscal section being extendible into the disc. The intradiscal section has sufficient rigidity to be advanceable through a nucleus pulposus and around an inner wall of an annulus fibrosus under a force applied longitudinally to the proximal end, sufficient flexibility in a direction of a disc plane to be compliant with the inner wall, but insufficient penetration ability to be advanceable out through the annulus fibrosus under the force. The apparatus also has an electromagnetic energy device located at the intradiscal section. Methods of using the apparatus are also provided.