Liquid infusion apparatus for radiofrequency tissue ablation

Abstract

An apparatus for delivering electrical energy includes a cannula and one or more needles extendable from and retractable into a lumen of the cannula. A distal portion of each needle is extendable from the lumen and terminates in a tissue-piercing distal tip. Each distal portion is formed from an electrically conductive and porous material, thereby providing a porous electrode through which electrolytic fluid may flow for delivering electrical energy to tissue surrounding the distal portion. The cannula is introduced into a tissue structure of a patient, the one or more needles are advanced from the cannula, saline is introduced from the porous material to surrounding tissue, and electrical energy from an RF generator is delivered to ablate tissue within the tissue structure.

Description

FIELD OF INVENTION [0001] The present invention relates generally to apparatus for infusing fluids into tissue, such as a tumor, to enhance thermal heating and ablation of the tissue using radio frequency electrical energy. BACKGROUND [0002] Electrosurgical instruments for delivering radio frequency (RF) electrical energy into solid tissue are known. For example, published PCT application WO 96 / 29946 discloses electrosurgical probes that include a number of independent wire electrodes that may be extended into tissue from the distal end of a cannula. The electrodes may be energized in a monopolar or bipolar manner to heat and necrose a target tissue region. Such probes have been suggested for treating tumors within organs, such as the liver, kidney, pancreas, stomach, and spleen. [0003] To enhance heating and necrosis, saline may be injected into the target region before delivering electrical energy. Generally, this involves advancing a needle from a syringe into the tissue before o...

AI Technical Summary

Benefits of technology

[0010] The opposing members include one or more electrodes for delivering electrical energy to tissue engaged between the opposing members. One or more hollow needles extend from an inner surface of at least one, and preferably each, of the opposing members. Each needle may include a sharpened tip for penetrating tissue engaged between the opposing members and an outlet in the sharpened tip communicating with a lumen in the opposing member for delivering conductive fluid from the lumen into tissue penetrated by the sharpened tip. A source of electrical energy may be coupled to the electrodes for delivering

Problems solved by technology

Saline may increase heating of the tissue, thereby increasing the size of the resulting lesion, as compared to energizing the electrodes without saline.

Because of inhomogeneities in the tissue of the target region, however, the saline injected by the syring

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