Disclosed methods and devices treat lower back pain from degenerated or injured intervertebral discs. Electrodes connected to a pulse generator deliver electrical impulses to nerves located within the posterior longitudinal ligament and posterior annulus fibrosus of lumbar intervertebral discs. Percutaneous and paddle leads containing the electrodes are disclosed. The percutaneous lead, designed to prevent inappropriate stimulation of the thecal sac, is inserted in the anterior epidural space using a special cannula and lead blank. Paddle leads are configured individually for implantation in each patient. The electrical stimulation may reduce back pain reversibly, with or without the simultaneous use of non-thermal irreversible electroporation. If such stimulation is unsuccessful, nerves in the ligament or annulus fibrosus may then be injured therapeutically without repositioning the lead, using impulses that result in heating, wherein a thermal insulator covers the thecal sac, thereby shielding nerves within the thecal sac from potential heat damage.
