Systems and methods are described for treating tissue with thermal energy while minimizing the amount of thermal energy to which adjacent tissue is exposed. A surgical instrument for delivering thermal energy to a section of tissue during percutaneous surgery, includes: an elongated shaft having a proximal end and a distal end; and a split tip electrode coupled to the distal end, the split tip electrode i) including a first component and a second component coupled to the first component, and ii) defining a principle axis. The thermal energy is delivered to the section of tissue so as to heat the section of tissue asymmetrically with regard to the principle axis of the split tip electrode. The systems and methods provide advantages in that thermal energy can be directed to one side of the split tip so that a first of two juxtaposed areas of a surgical site can be heated while a second of the two juxtaposed layers is substantially not heated. In alternate embodiments a portion of the site may be actively cooled while an adjacent portion of the site may be actively cooled.