Apparatus and methods for treating back pain of a patient by denervation of an intervertebral disc or a region of the posterior longitudinal ligament by the controlled application of heat to a target tissue. In one embodiment, the invention may include a procedure combining both decompression of a disc, and denervation of the annulus fibrosus. In one embodiment, a method of the invention includes positioning an active electrode of an electrosurgical instrument in at least close proximity to an intervertebral disc, and applying at least a first high frequency voltage between the active electrode and a return electrode, wherein nervous tissue within the annulus fibrosus is inactivated, and discogenic pain of the patient is alleviated. In one embodiment, the invention includes positioning a first electrode of a dual-shaft electrosurgical instrument at a first location in relation to a target disc, positioning a second electrode of the instrument at a second location, and applying a high frequency voltage between the first and second electrodes, wherein the first and second electrodes are disposed on separate shafts of the instrument.