Tissue surface treatment apparatus and method

A method of surface treatment of a target tissue site, the method comprising:

• providing a tissue surface treatment apparatus, the apparatus comprising an expandable member including a tissue contacting surface and an energy delivery device, the expandable member having a non-deployed state and an expanded or deployed state, the energy delivery device including at least one electrode with a tissue penetrating distal end, the at least one electrode being advanceable by or through the expandable member to a selected deployment depth within target tissue site to define an ablation volume at least partly bounded by the tissue surface;
• positioning the apparatus at the target tissue site;
• deploying the expandable member to at least partially engage the target tissue surface;
• advancing the at least one electrode to the selected deployment depth beneath a tissue surface while avoiding a critical structure;
• delivering ablative energy from the energy delivery device;
• creating an ablation volume at a controlled depth below the tissue surface responsive to the electrode deployment depth;
• and
• minimizing injury to the critical structure responsive to the electrode deployment depth.

A method of controlling an ablation volume depth during surface treatment of a target tissue site, the method comprising:

• providing a tissue surface treatment apparatus, the apparatus comprising a housing having a proximal end and a distal end having a tissue contact surface configured to at least partially immobilize the tissue surface, the housing defining an interior;
• an energy delivery device positionable in the housing interior, the energy delivery device including at least one electrode with a tissue penetrating distal end, the at least one electrode configured to be advanced from the housing interior to a selected deployment depth in a target tissue site to define an ablation volume at least partly bounded by the tissue surface;
• positioning the tissue contact surface on a target tissue surface;
• at least partially immobilizing the tissue surface utilizing the tissue contact surface;
• advancing the at least one electrode to the selected deployment depth beneath a tissue surface while avoiding a critical structure;
• delivering ablative energy from the energy delivery device;
• creating an ablation volume at a controlled depth below the tissue surface responsive to the electrode deployment depth;
• and
• minimizing injury to the critical structure responsive to the electrode deployment depth.