An externally guidable intervertebral disc apparatus manipulates disc 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 has an intradiscal section at its distal end. The intradiscal section is extendible into the disc, has sufficient rigidity to be advanceable through the nucleus pulposus and around the annulus fibrosus of the disc under a force applied longitudinally to the proximal end, has sufficient flexibility in a direction of the disc plane to be compliant with the inner wall, and has insufficient penetration ability to be advanceable out through the annulus fibrosus under the applied force. A thermal energy delivery device is located in the intradiscal section for preferentially heating the selected location of the disc. The apparatus is used to locally and controllably heat but not char or burn tissue in a disc. Such heat shrinks the collagen component.