Some implementations include a coaxial bipolar ablation instrument comprising an outer needle and an inner needle inserted into the outer needle. The instrument can also include a first insulating layer disposed between the inner needle and the outer needle, and a second insulating layer disposed over a portion of the outer needle. The instrument can further include a first exposed region of the instrument disposed near a proximate end of the instrument, the first exposed region including a first exposed portion of the inner needle and a first exposed portion of the outer needle, the first exposed region constructed to provide contact to a connector, and a second exposed region of the instrument disposed near a distal end of the instrument, the second exposed region forming the active region of the instrument and including a second exposed portion of the inner needle and a second exposed portion of the outer needle.