Devices and methods for delivering fluid to tissue during ablation therapy

Inventors

Curley, Michael G. • Eberl, Gregory R. • Clevenger, Jason M. • Howard, Michael T. • Delly, Erik

Assignees

Thermedical Inc

Abstract

Devices and methods for delivering fluid to tissue during ablation therapy are described herein. An exemplary device can include an elongate body having an inner lumen, outlet ports, and an ablation element configured to heat tissue. A flow resistance of the elongate body can increase along a length of the elongate body containing the outlet ports in a proximal to distal direction. This can be accomplished by, for example, varying outlet port size or relative spacing, decreasing a cross-sectional area of the inner lumen through which fluid can flow using a flow diverter or tapered inner lumen sidewalls, or limiting a ratio between a total area of the outlet ports and a cross-sectional area of the inner lumen. Adjusting flow resistance of the elongate body can provide more uniform fluid distribution or a desired non-uniform distribution.

Core Innovation

The invention relates to fluid-enhanced ablation therapy using an ablation device with an elongate body having an inner lumen, a tissue-puncturing distal tip, and a fluid delivery portion extending along a length of the elongate body. The fluid delivery portion includes a plurality of outlet ports configured to deliver fluid from the inner lumen to tissue surrounding the elongate body while an ablation element is configured to heat tissue surrounding the elongate body. The fluid delivery portion is configured to control fluid emission and distribution in relation to location along the elongate body length.

In the device, the fluid delivery portion is configured such that less than about 70% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a distal 25% of the fluid delivery portion. Additional quantitative distribution constraints can apply for different portions of the elongate body, including outlet ports disposed in a proximal 25% of the fluid delivery portion with corresponding volume limitations. The outlet-port region and emission volumes are arranged to produce a more uniform or selectively biased fluid distribution within tissue.

The invention further addresses configurations for delivering fluid with substantially uniform flow over a substantial portion of a length of the elongate body, including over at least about the distal 10%, at least about the distal 50%, or over substantially all of the length. In another aspect, the substantially uniform flow is provided over a portion of a length of the elongate body that is configured to be inserted in tissue. The described configurations are implemented using an elongate body with an inner lumen, outlet ports, and an ablation element configured to heat tissue, including embodiments that incorporate an internal flow diverter and outlet-port geometry considerations.

Claims Coverage

The independent claims include three inventive concepts: (i) a fluid distribution limitation tied to a distal 25% emission volume constraint, (ii) uniform fluid flow over a substantial portion of the elongate body length, and (iii) uniform fluid flow over a portion of the elongate body configured to be inserted in tissue. Across these independent claims, the main inventive features are centered on controlling where fluid is emitted and constraining the distribution to be substantially uniform over defined length portions.

Overall, the independent claims cover ablation devices that combine an elongate body with an inner lumen, outlet ports, and an ablation element, with the inventive aspect focused on quantitative control of fluid emission from defined longitudinal regions and on delivering substantially uniform fluid flow over either a substantial length portion or an inserted portion of the elongate body.

Stated Advantages

Documented Applications