Patent ID: 7569052

Claim:
A tissue ablation system, comprising: an elongate member having a proximal end and a distal end; a ground electrode element mounted to the distal end of the elongate member, the ground electrode element being exposed to contact bodily fluid; a protective element mounted to the distal end of the elongate member, wherein the protective element at least partially covers the ground electrode element to prevent the ground electrode element from contacting adjacent solid tissue, and wherein the protective element is incapable of conveying electrical energy between the solid tissue and the ground electrode element; and an ablation electrode element configured for being positioned adjacent a target tissue region, such that electrical energy, when conveyed between the ablation electrode element and the ground electrode element, ablates the target tissue region without ablating the solid tissue adjacent the ground electrode element; wherein the protective element comprises a cage assembly, and wherein the cage assembly comprises a ring element that coaxially surrounds and is slidable relative to the elongate member.