The present disclosure relates to methods of performing nucleoplasty including the step of providing an elongated thermal or electromagnetic probe having a proximal end, a distal end and having a guidable region adjacent the distal end thereof. The method further includes the steps of introducing the guidable region of the probe into a nucleus of an intervertebral disc; activating the probe; increasing the amplitude of the activated probe until an effect is obtained on a nervous system; and noting the amplitude at which the effect on the nucleus is observed. The method further includes the step of re-activating the probe to treat the nucleus, wherein the probe is activateable up to the amplitude at which the effect on the nervous system indicates that damage to critical nerve tissue is avoided.