U.S. patent application number 10/653854 was filed with the patent office on 2004-04-15 for cryosurgical probe with adjustable freeze zone.
Invention is credited to Damasco, Sanford D., Eum, Jay J., Yu, Xiaoyu.
Application Number | 20040073203 10/653854 |
Document ID | / |
Family ID | 25499437 |
Filed Date | 2004-04-15 |
United States Patent
Application |
20040073203 |
Kind Code |
A1 |
Yu, Xiaoyu ; et al. |
April 15, 2004 |
Cryosurgical probe with adjustable freeze zone
Abstract
A cryosurgical probe includes an actuator housing assembly and
an actuator assembly. The actuator housing assembly includes an
actuator housing having an elongated central opening therethrough.
The actuator housing has a proximal end portion and a distal end
portion. A delivery system for a cryogenic fluid, includes a first
end secured to the proximal end portion of the actuator housing. An
insulation layer has a proximal portion securely attached to the
proximal end portion of the actuator housing. An actuator assembly
includes a rotatable actuator having a portion thereof contained
within the actuator housing. The rotatable actuator is rotatable
relative to the actuator housing. A cryosurgical shaft assembly is
securely attached to the rotatable actuator. The insulation layer
extends along an inner surface of the cryosurgical shaft to define
insulated portions of the cryosurgical shaft and uninsulated
portions. The relative disposition of insulated and uninsulated
portions of the cryosurgical shaft assembly defines at least one
freeze zone, which is adjustable by relative rotation between the
rotatable actuator and the actuator housing.
Inventors: |
Yu, Xiaoyu; (San Diego,
CA) ; Damasco, Sanford D.; (Irvine, CA) ; Eum,
Jay J.; (Irvine, CA) |
Correspondence
Address: |
LAWRENCE N. GINSBERG
ENDOCARE, INC.
201 TECHNOLOGY DRIVE
IRVINE
CA
92618
US
|
Family ID: |
25499437 |
Appl. No.: |
10/653854 |
Filed: |
September 2, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10653854 |
Sep 2, 2003 |
|
|
|
09957337 |
Sep 20, 2001 |
|
|
|
Current U.S.
Class: |
606/21 ;
606/23 |
Current CPC
Class: |
A61B 2018/00041
20130101; A61B 2018/0262 20130101; A61B 18/02 20130101; A61B
2017/00084 20130101; A61B 2018/00101 20130101; A61B 2017/00092
20130101; A61B 2017/00243 20130101 |
Class at
Publication: |
606/021 ;
606/023 |
International
Class: |
A61B 018/02 |
Claims
1. A cryosurgical probe for providing an adjustable freeze zone,
comprising: an actuator housing assembly, comprising: a) an
actuator housing having an elongated central opening therethrough,
said actuator housing having a proximal end portion and a distal
end portion; b) a delivery system for a cryogenic fluid, including
a first end secured to said proximal end portion of said actuator
housing; and, c) an insulation layer having a proximal portion
securely attached to said proximal end portion of said actuator
housing; and, an actuator assembly, comprising: a) a rotatable
actuator having a portion thereof contained within said actuator
housing, said rotatable actuator being rotatable relative to said
actuator housing; and, b) a cryosurgical shaft assembly securely
attached to said rotatable actuator, said insulation layer
extending along an inner surface of said cryosurgical shaft to
define insulated portions of said cryosurgical shaft and
uninsulated portions, the relative disposition of insulated and
uninsulated portions of said cryosurgical shaft assembly defining
at least one freeze zone which is adjustable by relative rotation
between said rotatable actuator and said actuator housing.
2. The cryosurgical probe of claim 1, wherein said delivery system
comprises: a) a cryostat assembly comprising a cryostat housing,
said cryostat housing including a cryostat housing attachment end
secured to said proximal end portion of said actuator housing; and,
b) a Joule-Thomson tube assembly securely positioned within said
actuator housing.
3. A cryosurgical probe for providing an adjustable freeze zone,
comprising: a stationary assembly, comprising: a) an actuator
housing having an elongated central opening therethrough, said
actuator housing having a proximal end portion and a distal end
portion; b) a cryostat assembly comprising a cryostat housing, said
cryostat housing including a cryostat housing attachment end
secured to said proximal end portion of said actuator housing; c) a
stationary cylindrical insulation layer having a proximal portion
securely attached to said proximal end portion of said actuator
housing; and, d) a Joule-Thomson tube assembly securely positioned
within said actuator housing; and, a positionable assembly,
comprising: a) a rotatable cylindrical actuator having a portion
thereof contained within said actuator housing, said cylindrical
actuator being rotatable relative to said actuator housing; and, b)
a cryosurgical shaft assembly securely attached to said rotatable
cylindrical actuator, wherein rotation of said rotatable
cylindrical actuator provides desired freezing.
4. The cryosurgical probe of claim 3, wherein said rotatable
cylindrical actuator is operatively engaged with said actuator
housing to provide axial movement therebetween during rotation of
said rotatable cylindrical actuator thereby changing the length of
said freeze zone.
5. The cryosurgical probe of claim 3, wherein said rotatable
cylindrical actuator is operatively engaged with said actuator
housing to provide axial movement therebetween during rotation of
said rotatable cylindrical actuator, thereby changing the length of
said freeze zone, said rotatable cylindrical actuator being
threadably engaged with said actuator housing.
6. The cryosurgical probe of claim 3, wherein said cryosurgical
shaft assembly comprises insulation formed on a selected portion
thereon to provide a rotatable freeze zone upon rotation of said
rotatable cylindrical actuator.
7. A cryosurgical probe for providing an adjustable freeze zone,
comprising: an actuator housing assembly, comprising: a) an
actuator housing having an elongated central opening therethrough,
said actuator housing having a proximal end portion and a distal
end portion; b) a cryosurgical shaft assembly securely attached to
said distal end portion of said actuator housing; an actuator
assembly, comprising: a) a rotatable actuator having a portion
thereof contained within said actuator housing, said rotatable
actuator being rotatable relative to said actuator housing, said
rotatable actuator having a proximal end portion and a distal end
portion; b) a delivery system for a cryogenic fluid secured to said
rotatable actuator; and, c) an insulation layer having a proximal
portion securely attached to said rotatable actuator, said
insulation layer extending along an inner surface of said
cryosurgical shaft to define insulated portions of said
cryosurgical shaft and uninsulated portions, the relative
disposition of insulated and uninsulated portions of said
cryosurgical shaft assembly defining a least one freeze zone which
is adjustable by relative rotation between said rotatable actuator
and said actuator housing.
8. The cryosurgical probe of claim 7, wherein said delivery system
comprises: a) a cryostat assembly comprising a cryostat housing,
said cryostat housing including a cryostat housing attachment end
secured to said proximal end portion of said actuator housing; and,
b) a Joule-Thomson tube assembly securely positioned within said
actuator housing.
9. A cryosurgical probe for providing an adjustable freeze zone,
comprising: a stationary assembly, comprising: a) an actuator
housing having an elongated central opening therethrough, said
actuator housing having a proximal end portion and a distal end
portion; b) a cryosurgical shaft assembly securely attached to said
distal end portion of said actuator housing; a positionable
assembly, comprising: a) a rotatable cylindrical actuator having a
portion thereof contained within said actuator housing, said
cylindrical actuator being rotatable relative to said actuator
housing; b) a cryostat assembly comprising a cryostat housing, said
cryostat housing including a cryostat housing attachment end
secured to said rotatable cylindrical actuator; c) a cylindrical
insulation layer having a proximal portion securely attached to
said rotatable cylindrical actuator; and, d) a Joule-Thomson tube
assembly securely positioned within said cylindrical actuator,
wherein rotation of said rotatable cylindrical actuator provides
desired freezing.
10. The cryosurgical probe of claim 9, wherein said rotatable
cylindrical actuator is operatively engaged with said actuator
housing to provide axial movement therebetween during rotation of
said rotatable cylindrical actuator thereby changing the length of
said freeze zone.
11. The cryosurgical probe of claim 9, wherein said rotatable
cylindrical actuator is operatively engaged with said actuator
housing to provide axial movement therebetween during rotation of
said rotatable cylindrical actuator, thereby changing the length of
said freeze zone, said rotatable cylindrical actuator being
threadably engaged with said actuator housing.
12. The cryosurgical probe of claim 9, wherein said rotatable
cylindrical actuator is operatively engaged with said actuator
housing to provide axial movement therebetween during rotation of
said rotatable cylindrical actuator, thereby changing the length of
said freeze zone, said rotatable cylindrical actuator being
threadably engaged with said actuator housing.
13. The cryosurgical probe of claim 9, wherein said cryosurgical
shaft assembly comprises insulation formed on a selected portion
thereon to provide a rotatable freeze zone upon rotation of said
rotatable cylindrical actuator.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Ser. No.
09/957,337 filed Sep. 20, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to cryosurgical probes and
more particularly to a cryosurgical probe that provides an
adjustable freeze zone.
[0004] 2. Description of the Related Art
[0005] Conventional cryosurgical probes generally have the probe
tip permanently affixed to a probe instrument body, including a
handle member, for example. Other probes were invented long ago
which involved the use of removable and interchangeable probe tips,
for example, U.S. Pat. No. 4,211,231, entitled "Cryosurgical
Instrument", issued to R. P. Rzasa. In the surgical destruction of
tumors by freezing, different size probe tips may be required to
treat different sizes and shapes of tumors. However, it is not
generally practical or feasible to design or have available probe
tips which have the ideal or optimum freezing area/length for every
conceivable type of tumor. Therefore, there have been some
proposals in the prior art to provide cryosurgical probe devices
with means for adjusting the freezing zone by manipulating the
length or penetration of the coolant delivery and/or coolant line
with respect to the expansion chamber of the probe tip.
[0006] U.S. Pat. No. 3,398,738, entitled "Refrigerated Surgical
Probe," issued to B. L. Lamb et al, discloses a cryosurgical probe
in which the opening of its liquid refrigerant delivery tube may be
longitudinally or axially adjustable. This manipulates the rate of
flow of refrigerant. It does not change the freeze zone.
[0007] U.S. Pat. No. 4,015,606 to Mitchiner, et al. discloses a
cryosurgical probe having a cooling chamber that is permanently
separated from the insulating chamber in which a supply conduit
extends into the cooling chamber of the probe tip, wherein the
freeze zone in the cooling chamber is controlled by adjusting the
position of the refrigerant exhaust conduit in the tip relative to
the position of the supply conduit. However, only minor, if any,
adjustment is available with this device. Furthermore, the problems
inherent in permanent vacuum seals still exist.
[0008] U.S. Pat. No. 6,551,274, entitled "Cryoablation Catheter
With An Expandable Cooling Chamber" discloses a cryoablation
catheter having an expandable cooling chamber in which the cooling
fluid, preferably a gas, serves to expand the expandable cooling
chamber while simultaneously cooling the chamber. The cryoablation
catheter includes an outer tubular member capable of insertion into
the vessels of the body. An expandable cooling chamber, which
preferably takes the form of a distendable balloon, is disposed at
the distal end of the outer tubular member. An inner tubular member
is disposed within the outer tubular member and extends through a
passageway in the wall of the outer tubular member. The inner
tubular member serves to carry a cooling fluid to the interior of
the expandable cooling chamber. A fluid expansion nozzle is
disposed on the distal end of the inner tubular member. Preferably
the fluid expansion nozzle takes the form of a Joule-Thomson
nozzle. By applying a cooling fluid to the inner tubular member it
is possible to expand the expandable cooling chamber while
simultaneously cooling the chamber.
[0009] U.S. Pat. Nos. 6,547,785 and 6,497,703, each entitled
"Cryoablation Catheter For Long Lesion Ablations," each disclose a
cryoablation catheter, comprising an outer tubular body with a
closed distal end to form a fluid cooling chamber and an inner
tubular member having a proximal end adapted to receive fluid
suitable for cryoablation and a distal end coupled to a fluid
expansion nozzle wherein the inner tubular member is movable in an
axial direction to thereby change the position of the nozzle within
the fluid cooling chamber.
[0010] The '703 patent discloses the concept of "dragging" the
ablation tip, or the cooling tip, of a cryoablation catheter along
a line in order to create a long lesion. In order to accomplish
this function, the cryogenic cooling nozzle is moved longitudinally
along the inside of a cooling chamber to thereby cause the outer
surface of the cooling chamber to be cooled along a linear path
which in turn creates a linear lesion along the path.
[0011] The '785 patent emphasizes that the catheter system includes
a nozzle control system which is comprised of an inner ring member
formed of a magnetic material which is mounted on the proximal end
of the inner tubular member, and an outer ring member formed of
magnetic material which is slidably mounted on the outer tubular
member. Because of the magnetic attraction between these two
magnetic members, when an outer ring member is moved along the
outer tubular member it "pulls" or draws an inner magnetic ring
member along with the outer magnetic ring member to thereby cause
the inner tubular member to be moved longitudinally which in turn
causes the fluid expansion nozzle to be moved longitudinally within
the cooling chamber.
[0012] Both of these patents involve changing the location of the
freeze zone but do not increase or increase the length of the
freeze zone.
SUMMARY OF THE INVENTION
[0013] In one broad aspect, the present invention is embodied as a
cryosurgical probe for providing an adjustable freeze zone. The
cryosurgical probe includes an actuator housing assembly and an
actuator assembly. The actuator housing assembly includes an
actuator housing having an elongated central opening therethrough.
The actuator housing has a proximal end portion and a distal end
portion. A delivery system for a cryogenic fluid, includes a first
end secured to the proximal end portion of the actuator housing. An
insulation layer has a proximal portion securely attached to the
proximal end portion of the actuator housing.
[0014] An actuator assembly includes a rotatable actuator having a
portion thereof contained within the actuator housing. The
rotatable actuator is rotatable relative to the actuator housing. A
cryosurgical shaft assembly is securely attached to the rotatable
actuator. The insulation layer extends along an inner surface of
the cryosurgical shaft to define insulated portions of the
cryosurgical shaft and uninsulated portions. The relative
disposition of insulated and uninsulated portions of the
cryosurgical shaft assembly defines at least one freeze zone which
is adjustable by relative rotation between the rotatable actuator
and the actuator housing.
[0015] In one preferred embodiment the rotatable actuator is
operatively engaged with the actuator housing to provide axial
movement therebetween during rotation of the rotatable actuator
thereby changing the length of the freeze zone.
[0016] In another preferred embodiment, instead of changing the
length of the freeze zone, rotation of the actuator housing
relative to the rotatable actuator changes the position of
insulation located on a selected portion of the cryosurgical shaft
assembly and effects an adjustment in the freeze zone.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a cross sectional view, partially in cross
section, of a first embodiment of the cryosurgical probe of the
present invention in which the freezing zone can adjusted to be
longer or shorter.
[0018] FIG. 2 is another cross sectional view of the FIG. 1
embodiment, showing the shaft assembly detracted relative to the
insulation, illustrating how the freeze zone length is
decreased.
[0019] FIG. 3 is a cross sectional view, partially in cross
section, of the cryosurgical probe, including its fluid supply
line.
[0020] FIG. 4 is a cross sectional view of another embodiment in
which the cryosurgical probe is angled.
[0021] FIG. 5 is a cross sectional view, partially in cross section
of another embodiment in which there is no longitudinal relative
movement of the cryosurgical shaft assembly relative to the
actuator housing, and instead, insulation is located on a selected
portion of the cryosurgical shaft assembly so that rotation effects
a change in the freeze zone.
[0022] FIG. 6 is a view taken along line 6-6 of FIG. 5.
[0023] FIG. 7 is a cross sectional view, partially in cross
section, of another embodiment of the cryosurgical probe of the
present invention in which the actuator housing and the actuator
are reversed.
[0024] FIG. 8 is another cross sectional view of the FIG. 8
embodiment, showing the shaft assembly detracted relative to the
insulation, illustrating how the freeze zone length is
decreased.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Referring now to the drawings and the characters of
reference marked thereon, FIGS. 1 and 2 illustrate a preferred
embodiment of the cryosurgical probe of the present invention,
designated generally as 10. The cryosurgical probe 10 includes an
actuator housing assembly (i.e. stationary assembly), designated
generally as 12, and an actuator assembly (i.e. positionable
assembly), designated generally as 13. The stationary assembly 12
includes an actuator housing 14 having an elongated central opening
therethrough. The actuator housing 14 has a proximal end portion 16
and a distal end portion 18. The actuator housing is preferably
formed of a hard metal such as stainless steel.
[0026] A cryostat assembly 20 includes a cryostat housing 22. The
cryostat housing 22 includes a cryostat housing attachment end 24
secured to the proximal end portion 16 of the actuator housing 14.
The cryostat assembly 20 also includes a cryostat 26 that comprises
a coiled heat exchanger. A cryostat inlet receives gas entering the
cryostat while a cryostat outlet provides the gas to the
Joule-Thomson nozzle, as will be explained below. The coiled heat
exchanger is coiled around a mandrel. In between each winding of
the heat exchanger, gaps are formed between the coil and the main
body portion, and gaps are formed between the coil and the mandrel.
This construction is known as a Giaque-Hampson heat exchanger. The
heat exchanger, which is an integral part of the high pressure gas
pathway, is made with finned tubing, with numerous fins throughout
its length.
[0027] A stationary cylindrical insulation layer 28 has a proximal
portion 30 securely attached to a proximal end portion 16 of the
actuator housing 14 through a spacer 32. The insulation layer 28
may be, for example, a vacuum, a space or it may formed of an
insulation material such as Teflon.RTM. or glass fiber.
[0028] A Joule-Thomson tube assembly 34 is securely positioned
within the actuator housing 14. The Joule-Thomson tube assembly 34
may be formed of, for example, stainless steel.
[0029] The positionable assembly 13 of the cryosurgical probe 10
includes a rotatable cylindrical actuator 36 having a portion
thereof contained within the actuator housing 14. The cylindrical
actuator 36 is rotatable relative to the actuator housing 14,
preferably through the use of threads 38. A cryosurgical shaft
assembly 40 is securely attached to the rotatable cylindrical
actuator 36 so that that there is no relative rotation
therebetween. The cryosurgical shaft assembly 40 includes an outer
sheath that is preferably formed of stainless steel.
[0030] In the embodiment shown in FIGS. 1 and 2 the threads 38 are
utilized to provide the required rotation of the cylindrical
actuator 36 relative to the actuator housing 14. Therefore, as can
be seen in FIG. 2, during operation, as the cylindrical actuator 36
is rotated relative to the actuator housing 14 so that it moves
longitudinally inwardly, the Joule-Thomson tube assembly remains
stationary but the cryosurgical probe tip 41 moves longitudinally
inwardly. Thus, the boiling chamber length deceases from L1 to L2,
where L2=L1-DX, where DX is the distance that positionable assembly
13 is detracted. This provides a commensurate decrease in the
freeze zone length. The boiling chamber length, L, is shown as the
distance from the end of the insulation layer 28 to the end of the
expansion chamber 42 that contains the discharging gas.
[0031] Referring now to FIG. 3, the remainder of the cryosurgical
probe is shown including a fluid supply line assembly including a
the high pressure fluid supply line 44 surrounded by a flexible
hose 46 which terminates with a high pressure connector 47. A
temperature measurement device, i.e. a thermocouple 48, is
positioned within the elongated shaft assembly, extends through the
fluid supply line assembly and is connectable to a data acquisition
system. The thermocouple 48 is used to measure and monitor the
temperature inside the cryosurgical probe.
[0032] Fluid flow through the cryosurgical probe is as follows.
High pressure fluid, preferably gaseous argon, and preferably at a
pressure of about 3000 psi, is supplied to the assembly through
high pressure fitting 47, flows through gas supply line 44, through
the cryostat, i.e. heat exchanger 26, through the Joule-Thomson
tube assembly 34 and out the Joule-Thomson nozzle 50. The high
pressure gas expands within the expansion chamber 42 and cools to
cryogenic temperatures. Condensation of the gas is preferably
avoided but can be tolerated. After expanding, the gas is at lower
pressure and exhausts over the exhaust gas pathway that includes
flow over the outside of the coils of the heat exchanger 26.
Because it is now cold, it cools the gas flowing inside the coils.
This makes cooling more efficient and achieves colder temperatures.
After passing through the heat exchanger, the exhaust gas flows
through the remainder of the exhaust gas pathway. The exhaust gas
is, typically, eventually vented to the atmosphere.
[0033] Prior art warming methods such as exhaust blocking, reverse
flow heat transfer, and electrical heating can be employed. The
preferred method of warming is to supply high pressure helium gas
through the supply line, heat exchanger and Joule-Thomson nozzle.
Helium gas heats up when expanded through the gas outlet. Thus, the
supply of gas to the probe can be switched from high pressure
nitrogen or argon to high pressure helium to effect rapid
re-warming of the nozzle. Helium gas heats up when expanded through
the gas outlet. Thus, the supply of gas to the probe can be
switched from high pressure nitrogen or argon to high pressure
helium to effect rapid re-warming of the cryosurgical probe.
[0034] Although the cryosurgical probe of the present invention has
been shown as being straight it may be shaped to accommodate
varying uses. For example, referring now to FIG. 4, an embodiment
is illustrated, generally designated 52, in which a housing
extension 53 is curved to make the invention particularly useful,
for example, where space limitations exist. This may be useful, for
example, if the cryosurgical probe is utilized in a CT device. In
addition to its utilization relative to CT guidance, the
cryosurgical probe 52 may be used with a variety of guidance tools,
such as MRI and ultrasound.
[0035] Referring now to FIG. 5, another embodiment is illustrated,
designated generally as 54. In this embodiment, threads are not
used. Instead, there is a radial extension 56 on the cylindrical
actuator 58 that engages a complimentary groove 60 on the actuator
housing 62 so when the positionable assembly is rotated relative to
the stationary assembly there is no longitudinal movement. As can
be seen in FIG. 6, insulation 64 is located on a selected portion
of the cryosurgical shaft assembly 66 so that rotation effects a
change in the freeze zone. In this figure the insulation 64 is
shown to be about 180 degrees. Obviously, it can be configured as
desired for the particular application.
[0036] Although the present invention has been discussed relative
to the use of a Joule-Thomson tube assembly in conjunction with a
cryostat assembly to provide a delivery system for a cryogenic
fluid, it is understood that various other types of cryogenic
delivery systems may alternatively be used such as liquid
nitrogen.
[0037] Referring now to FIGS. 7 and 8, an embodiment of the present
invention is illustrated, designated generally as 70, in which the
actuator housing and the cylindrical actuator are reversed. The
cryosurgical probe 70 includes an actuator housing assembly (i.e.
stationary assembly), designated generally as 72, and an actuator
assembly (i.e. positionable assembly), designated generally as 73.
The stationary assembly 72 includes an actuator housing 74 having
an elongated central opening therethrough and a cryosurgical shaft
assembly 76 securely attached to the distal end portion of the
actuator housing.
[0038] The actuator assembly 73 includes a rotatable cylindrical
actuator 78 having a portion thereof contained within the actuator
housing 74. The cylindrical actuator 78 is rotatable relative to
the actuator housing 74.
[0039] As in the previous embodiment, a cryostat assembly 80
comprises a cryostat housing 82. The cryostat housing 82 includes a
cryostat housing attachment end 84 secured to the rotatable
cylindrical actuator 78. A cylindrical insulation layer 86 has a
proximal portion securely attached to the rotatable cylindrical
actuator 78. A Joule-Thomson tube assembly 88 is securely
positioned within the cylindrical actuator. Thus, rotation of the
rotatable cylindrical actuator 78 provides desired freezing.
[0040] This embodiment may be modified, as was the previous
embodiment, to provide for longitudinal relative movement or only
radial motion (i.e. by a groove) so that rotation effects a change
in the freeze zone.
[0041] Although the present invention has been discussed above with
respect to a cryosurgical probe having with a rigid outer sheath,
the cryosurgical probe may be made to be malleable by including at
least one malleable segment thereon. Malleable segments are formed
of material that permit reshaping and bending to reposition the
ablating surface for greater ablation precision. An example of a
cryosurgical probe having malleable characteristics is disclosed
and claimed in patent application Ser. No. 09/957,337, Pub. No.
U.S. 2003/0055415 A1, filed on Sep. 20, 2001 entitled Malleable
Cryosurgical Probe, incorporated in its entirety herein by
reference.
[0042] One method for providing malleable characteristics includes
providing a malleable shaft with a bellows portion. Patent
application Ser. No. 10/057,033, Pub. No. U.S. 2003/0055416 A1,
filed on Jan. 23, 2002 entitled Cryosurgical Probe With Bellows
Shaft, incorporated in its entirety herein by reference, discloses
use of a bellows portion for providing the necessary reshaping and
bending.
[0043] If the cryosurgical probe is utilized in combination with
ultrasound the outer sheath may have an echogenic coating with, for
example, a porous microstructure having the ability to trap
microscopic air bubbles. This creates thousands of highly efficient
ultrasound reflectors on the surface of the sheath.
[0044] Other embodiments and configurations may be devised without
departing from the spirit of the invention and the scope of the
appended claims.
* * * * *