Patent ID: 12239354

DETAILED DESCRIPTION

The description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of these disclosures. While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and will be described in detail herein. The objectives and advantages of the claimed subject matter will become more apparent from the following detailed description of these exemplary embodiments in connection with the accompanying drawings.

It should be understood, however, that the present disclosure is not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives that fall within the spirit and scope of these exemplary embodiments. The terms “couple,” “coupled,” “operatively coupled,” “operatively connected,” and the like should be broadly understood to refer to connecting devices or components together either mechanically, electrically, wired, wirelessly, or otherwise, such that the connection allows the pertinent devices or components to operate (e.g., communicate) with each other as intended by virtue of that relationship.

FIG.1illustrates perspective view of a probe100in accordance with some embodiments presented herein. Probe100may have a first member102that has a first end portion104and a second end portion106. First member102may have elongated, hollow structure extending from the first end portion104to the second end portion106. This structure may be tubular, having a generally circular inner and outer diameters, and may have a generally constant inner and outer dimensions (e.g., radii) between the first end portion104and second end portion106. The first end portion104is coupled to a handle108. The first end portion104may be referred to as the proximal end of the first member102because of this connection to the handle108. Likewise, second end portion106may be referred to the distal end of the first member102because it is more distant from the handle108as well as other equipment (e.g., a fluid supply, a fluid return, electrical connections for temperature sensors, etc.).

The first member102may comprise various materials including stainless steel, Inconel, titanium, or other materials.

Handle108serves two primary functions. First, the handle108improves a surgeon's ability to physically manipulate the probe location and orientation. Second, the handle108may provide physical connections between the inlet and outlet fluid flow paths within the first member102and a fluid supply and a fluid return, respectively, as well as for any electrical connections between components of the first member102and support equipment. These connections may be physically grouped together in a bundle110that may be operably coupled to cryogen source111(which may include a fluid return, or the return may be separated therefrom), console113(cryogen source111may be integrated with console113).

Fluids utilized by probe100may include, but are not limited to, argon, gaseous nitrogen, helium, refrigerants, liquid nitrogen, and other fluids.

FIG.2is a perspective, cutaway view of the second end portion106of a probe100in accordance with some embodiments. The first member102is coupled to a tip112at the extreme distal end of probe100. Tip112may be rounded, or it may be sharpened to aid movement of the probe through tissue. Tip112may have a surface120that engages a surface122of the first member102. Once engaged, the tip112may be secured to the first member102. As shown inFIG.2, the surface120of tip112may be located on a flange that engages an inner surface122of the first member102, although other arrangements may be made. The Tip112may have an inner surface124that this conical, as shown inFIG.2, flat, rounded, or hollow.

Also shown inFIG.2is the second member114. Second member114may provide at least part of the pathway for fluid from the fluid supply to the probe tip112. The second member114may be positioned within first member102such that the second member114extends within the first member102. This extension may be adjacent to the second end portion106of probe100. This extension may be along a longitudinal axis of the first member102, around which the second member114may be centered. However, all embodiments are not so limited, and in some embodiments the second member114may extend generally along the longitudinal axis of the first member102but be displaced from the longitudinal axis. In some embodiments, the second member114may extend from the handle108at the first end portion104almost to the probe tip112. The second member114may have an elongated, hollow structure and may be tubular. Second member114may be comprised of various materials including stainless steel, copper, Inconel, titanium, brass ceramic, or other materials.

Like the second member114, the third member116may be have a hollow structure that extends along the longitudinal axis of first member102, and it may be generally tubular. The third member116may be disposed outward, and may radially circumscribe the second member114, along at least a portion of the extension of the second member114. In some embodiments, the third member116may be in contact with and secured to the second member114, for example, by brazing. A distal end126of the third member116may substantially enclose a portion of the second member114, for example, by radially circumscribing the second member114. Both the second member114and the third member116may have a distal end128and126, respectively, forming a surface that is generally perpendicular to the longitudinal axis of the first member102. As shown inFIG.2, these distal ends128and126of the second member114and third member116, respectively, may be coplanar with one another.

The third member116may comprise stainless steel, copper, ceramic, Inconel, titanium, brass, plastic or other materials.

FIG.3Ais an end-view cross section of a probe100in accordance with some embodiments, although this figure omits the second member114. As illustrated, the third member116may have an outer surface130that engages the inner surface122of the first member102at one or more points132. The third member116may be constructed such that it has an outer dimension ‘D’ that is sufficiently near to an inner dimension of the first member102such that the third member116is held in position with the first member102. The outer surface130of the third member116may also have one or more sections134that have a dimension, measured across the longitudinal axis of the first member102, that is less than the outer dimension ‘D’. This section(s)134, points of engagement132, and the inner surface122of the first member102together define a passage136that may extend along a longitudinal length of the third member116. This passage(s)136may be an annular passage. Section(s)134may be formed by machining the outer surface130of the third member116.

In operation, a fluid may flow through the passage(s)136between the third member116and the first member102after having first passed through the second member114and a region near tip112. This region may provide for the expansion of the fluid. By designing the passage(s)136with a small cross-sectional area, the bulk of the cooling fluid is closer to the inner surface122of the first member102than in designs (such as that referenced below) that use larger passages. Additionally, the velocity of the fluid in these passages is higher than in older designs in which the fluid passages have larger cross-sectional areas, such as that seen in U.S. Patent App. Pub. No. 2007/0149959, thereby reducing fluid boundary layer thickness and promoting heat transfer between the fluid and the first member102that is in thermal communication with surrounding tissue. Both of these features contribute to the improved thermal performance of the probes disclosed herein.

In some embodiments, some of the passages136may provide for an incoming fluid flow path from the proximal to the distal end of probe100, replacing some or all of the function and use of the second member114as describe above. In some embodiments, some of the other passages136may provide for an outgoing fluid flow path from the distal to proximal ends of probe100. In some embodiments, all of the passages136may be provide an inlet fluid flow path and second member114may provide the outlet fluid flow path.

The inventor has found that the location of the cross-sectional area of the passage(s)136, relative to the inner surface122of the first member102, has a significant effect on thermal performance. These cross-sectional area(s) of the passage(s)136are taken perpendicular to the longitudinal (major) axis of the first member102. This relative positioning of the cross-sectional area152of the passage(s)136, as seen inFIG.3B, can be defined by the percentage of the cross-sectional area located between an inner surface122of the first member102, and a boundary154located inwardly from the inner surface122of the first member102. This boundary is inwardly offset from the inner surface122of the first member102by a distance ‘D2’ that is 10% of the largest inside cross sectional radius defined by the inner surface122of the first member102. For example, in the case of a first member102having a circular inner cross section, the boundary is a circle that has a diameter that is 80% of the inside diameter of first member102. Significant improvements in thermal performance have been observed when at least 70% of the total cross-sectional area of the passage(s)136is located in this region between the inner surface122of the first member102and this boundary. In some embodiments, at least 80% of the total cross-sectional area of the passage(s)136is located in this same region. In some embodiments, at least 90% of the total cross-sectional area of the passage(s)136is located in this region. In some embodiments, at least 100% of the total cross-sectional area of the passage(s)136is located in this region.

The inventor has also found that particular ratios of the cross-sectional area of the passage(s)136to the cross-sectional area of the first member102exhibit improvements in the thermal performance of probe100. In these ratios, the inner surface122of the first member102defines the cross-sectional area within the first member102. The total cross sectional flow area of the passage(s)136, taken perpendicular to the longitudinal (major) axis of the first member102, is defined by the engagement of the third member116with the first member102. Ratios of the total cross-sectional flow area of the passage(s)136to the cross sectional area circumscribed within first member102by itself, having improved thermal performance include 0.05-0.3.

The cross-sectional profile of the third member116illustrated inFIG.3Ais a roughly hexagonal polygon having six locations of contact132between the third member116outer surface130and the inner surface122of the first member102, together defining a total of six passages136for the flow of the fluid. This profile is but one example. Another example is illustrated inFIG.4, a perspective view of the cross-sectional area for fluid flow within a portion of a probe100in accordance with some embodiments. This profile is largely similar to that provided inFIG.3, however, the locations132at the outer surface130of the third member116that engage the inner surface122of the first member102have a reduced width, measured perpendicular to the longitudinal axis of the first member102and, roughly, around the circumference of the third member116, such that the locations132are more akin to a point (or line when viewed along the length of third member116) of contact rather than an area, giving third member116the six sides of a hexagon.

Another exemplary cross-sectional area for fluid flow is illustrated inFIG.5. As shown, the engagement of third member116with the inner surface122of the first member102occurs in four locations132, defining four passages136. While this and earlier embodiments illustrate that the third member has a polygonal, or generally polygonal shape (which the expectation of possibly curved portions connecting the flat portions of the outer surface130), the third member116is not limited to having a polygonal outer shape.

Likewise, the number of locations132at which the outer surface130of the third member116engages the inner surface122of the first member102can vary from as little as one (where that location may extend over an area around the circumference of the third member116), to two, three, four, five, six, or even more. In turn, the number of locations132of engagement of the third member116and the first member102determines the number of passages between the two members.

A POSA will recognize that other shapes of the third member116may still result in the thermal improvements enabled by the features discussed herein.

The outer surface130of the third member116may have formed therein a plurality of channels138that direct the flow of fluid within, and sometimes between, the passages136. These channels138may have various shapes, as illustrated inFIGS.6A to6Dwhich are top-down views of the outer surface130of the third member116looking along the extension of the third member. As can be seen, these channels138may have a stepped shape, a series of alternating faces parallel and then perpendicular to the extension of third member116(FIG.6A), a series of zig-zag shapes (FIG.6B). In some embodiments, the shape may resemble zig-zag but using a series of continuously curving surfaces (FIG.6C). In some embodiments, the channels138may spiral around the third member116along its extension (FIG.6D). By alternating the direction of the fluid flow, channels138may cause a reduced boundary layer thickness of the fluid, thereby increasing the heat transfer coefficient. A POSA will recognize that other channel designs/patterns may be used to direct the flow of fluid within the passage(s)136.

Returning toFIG.2, the third member116may have a proximal end140that may be located radially outward of and surround the second member114, in embodiments in which the second member114extends through the length of the third member116. A fourth member118is located between the handle108and the proximal end140of the third member116. In some embodiments, fourth member118serves as a return line for the fluid after it has flowed through the passages136. The fourth members118may be a double wall construction, with or without a vacuum or insulating material in between, and insulates the proximal end of102from the cold working fluid, serving as a termination point of the cooling portion of the first member102. The fourth member118may be a hollow structure that extends within the first member102. This structure may be tubular, and may comprise stainless steel, Inconel, titanium, ceramic, or other materials. As shown inFIG.2, the fourth member118may be coaxial with and radially surround second member114(or other member that provides at least a portion of the flow path the fluid to the tip112). In some embodiments, such as that illustrated inFIG.7, a bulk head component119, may be utilized to seal around and isolate inlet and outlet tubing, that may be of the second member114and fourth member118, respectively. The inlet and outlet tubes may optionally be coaxial where they pass through the bulk head component119. The region proximal to the bulk head component119may be insulated by physical insulation material, by vacuum, or both.

The fourth member118and a member providing at least a portion of the inlet flow path (which may be second member114) may be surrounded by an insulating structure142between these members and first member102. Insulating structure142serves to reduce the transfer of heat between tissue surrounding the first member102and fluid, thereby serving as a termination point of the working, cooling portion of the first member102. Insulating structure142may comprise materials having low thermal conductivity, such as ceramics, and may utilize vacuum to aid in reducing heat transfer. This vacuum may be permanent, in that a vacuum is drawn in a sealed volume within structure142, or it may be actively drawn during operating of the probe by a pump.

Turning toFIG.8A, illustrated is a probe100in which the second member114contains an extension144in accordance with some embodiments, otherwise the embodiment ofFIG.8Ais largely similar to that ofFIG.2. Extension144serves to impinge the fluid upon the inner surface124of the tip112. Additionally, extension144of second member114serves to reduce the cross-sectional flow areas closer to the tip112. Both of these features may provide for improved heat transfer rates nearer the tip112.

As can be seen inFIG.8A, second members114and third members116are positioned within a first member102such that a distance measured between the distal end128of the extension144of the second member114and the tip112is less than a second distance measured between the distal end126of third member116and the tip112. In some embodiments, the outer dimension ‘D’ of the third member116may be larger than an inner dimension between the tip112where the tip engages the first member102. This larger dimension prevents the third member116from extending as far into the tip as the second member114. Extension144has a sufficiently smaller outer dimension such that it can extend within the tip112to a location that is radially surrounded by both surface120and122of the tip112and the first member102, respectively.

In some embodiments, such as that seen inFIG.8B, distancing members158, or projections, can be added to the distal face of third member116, to prevent the third member116and the second member114from extending too far in the distal direction towards the tip112. For example, distancing members158may have a combined width “CW” that is greater than the tip width “TW” of the tip112at its proximal end such that the distancing members158would engage a proximal surface of tip112, thereby preventing the third member116and the second member114from extending too far in the distal direction towards the tip112.

An extension146may also be added to the third member116such that a portion of the third member116extends into a region within the tip112such that the extension146is radially surrounded by a portion of the tip112, first member102, or both. Such an embodiment is shown in the cross-section view of the tip112of probe100ofFIG.9. The third member116contains a first portion having an outer dimension ‘D1’ that is larger than an inner dimension of the tip112, for example, between the surfaces120that engage first member102. Third member116may also contain a second portion, extension146, having an outer dimension “D2” which is less than the inner dimension of tip112at this same location. Extension146further reduces the cross-section flow area for the fluid, thereby increasing the heat transfer coefficient of the fluid in the region of the tip in the same manner as described above for the passages136between the third member116and the first member102, and beyond that by merely providing an extended second member114.

In some embodiments, the third member116may have a portion148between the larger first portion and the extended second portion. Portion148may be smooth. As used herein, ‘smooth’ describes a surface generally free of discontinuities (or “continuous”). Portion148may be smooth between its distal and proximal endpoints and be smooth or have a gradual transition between the first and second portions of the third member116. This smooth transition provided by portion148reduces resistance to the flow of fluid within probe100.

FIG.10is a perspective view of a third member116having an extension and a portion148.

In accordance with some embodiments, a probe100having a fifth member160adjacent to the tip112as illustrated inFIG.11A. Since fifth member160does not extend along the entire length of the third member116, a section150of the third member116provides at least a portion of the incoming fluid flow path upstream of the fifth member160. Second member114may extend along the longitudinal axis of the first member102near the proximal end of third member116, and may engage third member116to provide a portion of the inlet fluid flow path.

In some embodiments, the third member116may comprise the fifth member160in a unitary component, as illustrated inFIG.11B. Third member116may still engage second member114at its proximal end. Manufacturing a unitary third member116/fifth member160component providing for the function of both the third member116and the fifth member160may simplify assembly by reducing the number of components that may need to be connected to one another.

As shown inFIG.12, the second member114may be surrounded by the third member116at the proximal end of the third member116, and the second member114may provide the fluid flow path into the section150of the third member116. This arrangement provides for a greater ability to exchange heat between incoming fluid in section150and fluid flowing in the passages136between the third member116and the first member102. This internal heat transfer between the fluid allows for more consistent temperatures along the length of the probe100. As illustrated, member116may have a first inner dimension at its distal and proximal ends at which it engages fifth member160and second member114, respectfully, and a second inner dimension between its distal and proximate ends. This second inner dimension allows the fluid to flow closer to the passages136, and provides for a reduced radial thickness of the third member116in the section150when compared to its distal and proximal ends.

FIG.13is a block diagram of method1300of using a probe designed in accordance with some embodiments. The method starts at block1302. At block1304, a probe designed in accordance with one or more of the embodiments provided herein is provided. This probe is then coupled to a fluid supply and a fluid return at block1306. At block1308, the probe is positioned such that it is in contact with a target issue. Fluid is then supplied to the probe at block1310, and then exhausted from the probe to the fluid return at block1312. The method may end at block1314. A POSA will recognize that other, conventional methods and procedures for running fluid to and from a probe may be utilized with probe100as described in the embodiments herein.

The improvements to the internal design of a cryoprobe which utilizes an internal fluid (liquid, gas, mixed, or other phase) as the cooling medium disclosed herein improves the cooling performance of the probe. These improvements increase the heat transfer rate between the outer surface of the probe and the internal working fluid. This increased heat transfer rate can be used to either cool/freeze tissue more quickly, freeze larger regions of tissue, consume less fluid or energy for the same amount of cooling or freezing performance, provide for a more uniform temperature along the probe, or a combination of any of the aforementioned advantages.

The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of these disclosures. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of these disclosures.