Apparatus and methods for advancing and retracting a medical instrument within an introducer device, wherein the instrument includes a distal tip, a distal linear portion, a first distal curve, a substantially linear inter-curve portion, and a second proximal curve. The length of the distal linear portion and the angle of the first curve determine the position of the distal tip within a lumen of the introducer device, such that the distal tip occupies a substantially central transverse location within the lumen and the distal tip avoids contact with the introducer device. The length of the inter-curve portion and the angle of the second curve determine deflection of the distal tip from a longitudinal axis of the shaft when the second curve is extended distally beyond a distal end of the introducer device. Also, methods and apparatus for treating an
intervertebral disc by
ablation of disc tissue. A method of the invention includes positioning at least one
active electrode within the
intervertebral disc, and applying at least a first
high frequency voltage between the
active electrode(s) and one or more return
electrode(s), wherein the volume of the
nucleus pulposus is decreased, pressure exerted by the
nucleus pulposus on the annulus fibrosus is reduced, and
discogenic pain of a patient is alleviated. In other embodiments, a curved or steerable probe is guided to a specific
target site within a disc to be treated, and the disc tissue at the
target site is ablated by application of at least a first
high frequency voltage between the
active electrode(s) and one or more return
electrode(s). A method of making an electrosurgical probe is also disclosed.