Tissue surface treatment apparatus and method

A method of controlling ablation volume depth includes providing a treatment apparatus. The apparatus comprises a housing having a proximal and distal end including a tissue contacting surface. The housing defines an interior with an energy delivery device positionable in the interior. The energy delivery device includes at least one electrode with a tissue penetrating distal end and is configured to be advanced from the interior into a target tissue site to define an ablation volume. An advancement device is coupled to the energy delivery device and is configured to advance the at least one electrode. The at least one electrode is advanced to a selected deployment depth beneath a tissue surface while avoiding a critical structure. Energy is delivered from the energy delivery device. An ablation volume is created at a controlled depth below the tissue surface responsive to the deployment depth while minimizing injury to the critical structure.