A system and method for approaching the intervertebral disc through a percutaneous insertion from the back of a patient for thermal or electromagnetic treatment of an intervertebral disc, includes an elongated probe member having a guidable region adjacent its distal end with an undulating groove defined in its outer surface. The undulating groove is dimensioned to facilitate bending of the guidable region in at least one radial direction of movement relative to a longitudinal axis of the thermal probe. Preferably, the guidable region includes a plurality of undulating grooves, whereby adjacent undulating grooves are longitudinally spaced with respect to each other. The undulating grooves each define a sinusoidal configuration which may be arranged about an undulating axis extending in oblique relation to the longitudinal axis. The guidable region also includes a longitudinally extending backbone which resists bending of the guidable region in a radial direction of movement. The apparatus may also include a cannula to facilitate introduction of the thermal probe into the intervertebral disc. The cannula includes an arcuate end portion dimensioned to arrange the guidable region of the thermal probe at a desired orientation within the annulus fibrosis.