APPARATUS AND METHOD FOR ABLATION OF SOFT TISSUE SURROUNDING A BREAST CAVITY FOLLOWING LUMPECTOMY

Abstract

Methods and systems for delivering a cryogenic fluid to an inner surface of a surgical excision cavity, such as following breast tumor removal, are described. A single or dual balloon configuration can be utilized to deliver a cryogenic fluid to necrose tissue surrounding the tumor cavity in order to reduce the risk of recurrence of the cancer. The balloon can be optimally configured for maximum contact with the breast tumor bed.

Claims

1. A method for removing a tumor from solid tissue, said method comprising: surgically removing the tumor to create a tissue cavity having an exposed tissue surface in the solid tissue; inserting an expandable heat transfer surface surrounding an interior volume into the tissue cavity; expanding the expandable surface against the exposed tissue surface of the body cavity; and circulating a cooling fluid through the interior volume in order to cool and necrose the exposed tissue surface to a predetermined depth.

2. A method as in claim 1, wherein inserting the expandable heat transfer surface comprises inserting a single-walled balloon and expanding the balloon with the cooing fluid.

3. A method as in claim 1, wherein inserting the expandable heat transfer surface comprises inserting a double-walled balloon having an inner chamber and a space between an outer surface of the inner chamber and the expandable surface, wherein the cooling fluid is circulated through said space.

4. A method as in claim 3, wherein the inner chamber is expanded with a secondary fluid

5. A method as in claim 1, wherein the cooling fluid is pre-cooled.

6. A method as in claim 1, wherein the cooling fluid comprises a gas that undergoes a Joule Thomson expansion when introduced to the interior volume.

7. A method as in claim 1, wherein the cooling fluid comprises a liquid that has undergone an enthalpic expansion prior to circulation in the interior volume.

8. A method as in claim 1, wherein expanding the expandable surface comprises mechanically expanding the surface with a pull wire.

9. A method as in claim 1, further comprising stopping circulation of the cooling fluid through the interior volume of the expanded surface, circulating a warming fluid through the interior volume of the expanded surface, and circulating a cooling fluid the interior volume of the expanded surface a second time.

10. A probe for necrosing a marginal tissue region in a surgically created tissue cavity, said probe comprising: a shaft; an expandable heat transfer surface surrounding an interior volume at a distal end of the shaft, said expandable surface configured to conform to an inner surface of the surgically created tissue cavity when expanded therein; and a cryogenic fluid supply lumen and a separate cryogenic removal lumen, both lumens being disposed in the shaft.

11. The probe of claim 10, wherein the cryogenic fluid supply lumen is disposed concentrically about the cryogenic removal lumen.

12. The probe of claim 10, further comprising a secondary fluid supply lumen in the shaft

13. The probe of claim 10, wherein the expandable heat transfer surface comprises a single-walled balloon.

14. The probe of claim 10, wherein the expandable heat transfer surface comprises a double-walled balloon having an outer balloon and an inner balloon, wherein the expandable heat transfer surface is on an outside of the outer balloon and both (a) a space between the outer surface of the inner balloon and an inner surface of the outer balloon and (b) an interior of the inner balloon are is configures to receive fluids.

15. The probe of claim 14, wherein the space between the outer surface of the inner balloon and an inner surface of the outer balloon is configured to receive the cryogenic fluid and the interior of the inner balloon is configured to receive a secondary fluid.

16. The probe of claim 10, further comprising a vacuum lumen configured to draw a negative pressure in a region surrounding the expandable heat transfer surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1A-1E illustrate in cross-section a breast and the steps for treatment of a breast cancer using a cryogenic balloon.

[0024] FIG. 2 illustrates in a cross-sectional view a single balloon system for use with a cryogenic fluid that provides the delivery of a cryogenic fluid to the surgical cavity within the breast.

[0025] FIG. 3 illustrates in a cross-sectional view a single balloon system for use with a cryogenic fluid that provides the delivery of a cryogenic fluid to the surgical cavity within the breast and provides a secondary fluid path for balloon expansion and preliminary heat removal.

[0026] FIG. 4 illustrates in cross-sectional view a dual balloon system for use with a cryogenic fluid that provides the delivery of a cooling agent to the surgical cavity within the breast.

[0027] FIG. 5 illustrates in a cross-sectional view a single balloon system for use with a cryogenic fluid that provides the delivery of a cryogenic fluid to the surgical cavity within the breast and provides a suction path exterior to the tissue contacting balloon.

DETAILED DESCRIPTION

[0028] Cryo-balloon systems are configured to deliver cryogenic temperatures. e.g. freezing temperatures below −40° C., to the surrounding breast tissue perimeter defined by the walls of a surgical cavity post excision of a breast cancer to a distance of from 5 mm to 15 mm as defined by standard adjuvant therapeutic breast cancer norms. In balloon embodiments, cryoablative necrotizing energy is typically delivered to most or in the surrounding cavity wall, including both benign and malignant, by exposure to necrotizing cryoablative temperatures. Within the predefined treatment area, typically 5 mm to 15 mm, often, 5 mm to 20 mm, in depth of surrounding breast tissue and extending radially from the walls of the surgical cavity will undergo a necrotizing sub-freezing temperature gradient. Any remaining cells benign or malignant within this area will be necrotized, i.e. become non-viable.

[0029] An additional balloon configuration includes a secondary internal balloon to “pre-expand” the cryogenic cooling and tissue contacting balloon to effect increased system efficiency and reduce procedure time. Cryogenic fluid agents utilized are particularly useful for rapidly ablating (necrotizing soft tissue surrounding the walls of a surgical cavity). Suitable cryogenic fluids include, but are not limited to, carbon dioxide (CO.sub.2), nitrous oxide, liquid nitrogen, near-critical nitrogen, perfluoropropane, propane, and other refrigerants such as R124, R1270, and R600a with unique phase change properties.

[0030] FIG. 1 illustrates in cross-section a breast at steps of treatment for the surgical excision of a breast cancer followed by balloon cryo-ablation of a margin of soft tissue in the walls of the surgical cavity. FIG. 1A illustrates a cancer 10 in the breast 12. FIG. 1B illustrates a surgical cavity 14 in breast 12 with a surgical tract 16 after the cancer has been excised. Surgical excision may be performed using open surgical techniques or using one or more devices that incorporate minimally invasive access. FIG. 1C illustrates balloon system 20 placed within the surgical tract with partial inflation of the balloon 22 in surgical cavity 14. FIG. 1D illustrates a fully expanded balloon 22 with cryogenic fluid and commencement of ablation of the margin of soft tissue in the walls of the surgical cavity. FIG. 1E illustrates the breast 12 after the balloon system has been removed and the surgical tract closed. A margin of soft tissue 18 within the wall of the surgical cavity 14 has been ablated.

[0031] To accommodate different cavity dimensions and shapes, the balloons can be provided in multiple different sizes and shapes typically including at least spherical and spheroid geometries. As the balloons will typically be non-distensible, as defined elsewhere herein, sizes can further be adjusted controlling inflation pressures. In double-wall balloon constructions, as described elsewhere herein, a space between inner and outer balloons can be maintained by introducing a cryofluid into a circulation region between the balloons at a higher pressure than an inflation pressure for the inner balloon.

[0032] FIG. 2 illustrates a cross-sectional view of a single balloon cryo-ablation device 20. The tissue contacting balloon 22 is attached to support tube 24 and internally supported by end cap 26. Once the single balloon cryo-ablation device 20 is inserted into the breast, cryogenic fluid is infused into and circulated within the tissue contacting balloon 22 entering through supply tube 28 and, optionally a second supply tube 30, and exiting the tissue contacting balloon 22 through perforations within support tube 24 and a cryogenic fluid return tube 32.

[0033] FIG. 3 illustrates a cross-sectional view of a single balloon cryo-ablation device 40 with the additional of a secondary fluid path. Once the single balloon cryo-ablation device 40 is inserted into the breast, a secondary fluid such as air, CO2 gas, saline, or other fluid media or gas is infused into and circulated within the tissue contacting balloon 22 entering from secondary fluid supply tube 42 and, optionally an additional secondary fluid supply tube 44, and exiting the tissue contacting balloon 22 through perforations within inner support tube 24 and secondary fluid return tube 46. Once the tissue contacting balloon 22 is expanded within the tumor cavity and drained of the secondary fluid, cryogenic fluid is infused into and circulated within the tissue contacting balloon 22 entering from supply tube 28 and, optionally additional supply tube 30, and exiting the tissue contacting balloon 22 through perforations within inner support tube 44 and cryogenic fluid return tube 32.

[0034] FIG. 4 illustrates a cross-sectional view of a dual balloon cryo-ablation device 60. The expansion balloon 62 is attached to inner support tube 24 and partially perforated end cap 64. A tissue contacting balloon 22 is attached to outer support tube 66 and internally supported by the partially perforated end cap 64. Once the dual balloon cryo-ablation device 60 is inserted into the breast, the expansion balloon 62 is infused with a secondary fluid and circulated within the expansion balloon 62 entering from secondary fluid supply tube 68 and, optionally an additional secondary fluid supply tube 70, and exiting the expansion balloon 62 through perforations within inner support tube 24 and secondary fluid return tube 72. Once the expansion balloon 62 is expanded within the tumor cavity, cryogenic fluid is infused into and circulated within the tissue contacting balloon 22 entering from supply tube 28 and, optionally additional supply tube 30, and exiting the tissue contacting balloon 22 through perforations within end cap 64 and cryogenic fluid return tube 32.

[0035] FIG. 5 illustrates a cross-sectional view of a single balloon cryo-ablation device 80 with the additional of a co-axial suction channel 82 around the periphery of the proximal portion of a single balloon cryo-ablation device 20 to remove excess air or fluid between the tissue contacting balloon 22 and the tissue cavity. Once this material has been removed, the cryo-ablation process can be initiated.

[0036] An exemplary protocol comprises: [0037] Pre-cooled liquid cryofluid is pumped into the catheter connecting the cryo-balloon to the system console [0038] Within the balloon the cryofluid warms by removing thermal energy from the surrounding tissue −6-8 minutes “freeze” [0039] Within the console, the “used” (warmed) cryo-fluid is collected in a secondary container for subsequent reuse [0040] At the end of the first freeze cycle the circulation path is reversed and the warmed fluid is used to thaw the balloon −8-10 minute “thaw” [0041] A second 6-8 minute “freeze” is followed by a 8-10 minute “thaw” [0042] The thawed and deflated balloon can then be easily removed from the surgical cavity

[0043] Any elements described herein as singular can be pluralized (i.e., anything described as “one” can be more than one). Any species element of a genus element can have the characteristics or elements of any other species element of that genus. The media delivered herein can be any of the fluids (e.g., liquid, gas, or combinations thereof) described herein. The patents and patent applications cited herein are all incorporated by reference herein in their entireties. Some elements may be absent from individual figures for reasons of illustrative clarity. The above-described configurations, elements or complete assemblies and methods and their elements for carrying out the disclosure, and variations of aspects of the disclosure can be combined and modified with each other in any combination. All devices, apparatuses, systems, and methods described herein can be used for medical (e.g., diagnostic, therapeutic or rehabilitative) or non-medical purposes.