U.S. patent application number 15/013463 was filed with the patent office on 2016-05-26 for method for ultrasonic dissection of tissues.
The applicant listed for this patent is LifeCell Corporation. Invention is credited to Adrian F. Barbieri, Israel James Jessop, Benjamin T. Kibalo.
Application Number | 20160143655 15/013463 |
Document ID | / |
Family ID | 55410300 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160143655 |
Kind Code |
A1 |
Jessop; Israel James ; et
al. |
May 26, 2016 |
Method for Ultrasonic Dissection of Tissues
Abstract
Methods for dissecting tissues are provided. The methods
comprise selecting a tissue site comprising dermis and subdermal
fat connected to the dermis, and applying ultrasonic energy to the
tissue to remove at least a portion of the subdermal fat from the
dermis, wherein the ultrasonic energy is applied to minimize damage
to the dermis.
Inventors: |
Jessop; Israel James;
(Annandale, NJ) ; Kibalo; Benjamin T.; (Columbia,
MD) ; Barbieri; Adrian F.; (Branchburg, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LifeCell Corporation |
Branchburg |
NJ |
US |
|
|
Family ID: |
55410300 |
Appl. No.: |
15/013463 |
Filed: |
February 2, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13192023 |
Jul 27, 2011 |
9277933 |
|
|
15013463 |
|
|
|
|
61368354 |
Jul 28, 2010 |
|
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Current U.S.
Class: |
606/132 |
Current CPC
Class: |
A61B 2017/00761
20130101; A61B 17/320068 20130101; A61B 2017/00969 20130101; A61B
17/322 20130101; A61B 2017/320064 20130101; A61B 2017/3225
20130101 |
International
Class: |
A61B 17/322 20060101
A61B017/322 |
Claims
1. A system for separating dermal tissue from subdermal fat, the
system comprising: an ultrasonic probe having a wide blade for
efficiently delivering ultrasonic energy along a wide surface
area.
2. The system of claim 1, wherein the ultrasonic probe is
configured to deliver ultrasonic energy at a frequency of at least
60 kHz to a dermal-fat junction.
3. The system of claim 2, wherein the ultrasonic probe has a blunt
tip and is configured to emulsify or melt fat.
4. The system of claim 2, wherein the ultrasonic probe is sharp
configured to cut subdermal fat from dermis while delivering
ultrasonic energy.
5. The system of claim 1, further comprising: a cooling device
separate from the ultrasonic probe to cool a selection of
tissue.
6. The system of claim 5, wherein the selection of tissue comprises
a sheet of dermis and subdermal fat connected to the dermis.
7. The system of claim 6, wherein the cooling device is configured
to cool a surface of the sheet of dermis while the ultrasonic probe
delivers ultrasonic energy at a dermal-fat junction.
8. The system of claim 7, wherein the cooling device comprises a
solid supporting cold surface configured to directly contact the
dermis of the selection of tissue.
9. The system of claim 8, wherein the selection of tissue comprises
tissue that has been removed from a cadaver or animal source.
10. The system of claim 7, wherein the cooling device comprises a
cooling jacket configured to directly contact the dermis.
11. The system of claim 10, wherein the cooling jacket is
configured to receive a cooling fluid.
12. The system of claim 7, wherein the cooling device is configured
to provide a cooling fluid in direct contact with the dermis.
13. The system of claim 7, wherein the subdermal fat is attached to
a cadaver, and the ultrasonic energy is applied to separate the
dermis from the cadaver.
14. The system of claim 7, wherein the cooling device is configured
to supply a cooling fluid to the dermal-fat junction.
15. The system of claim 1, wherein the ultrasonic probe is
configured to deliver pulsed ultrasonic energy.
16. The system of claim 1, wherein the ultrasonic probe is
configured to deliver continuous ultrasonic energy.
17. The system of claim 1, wherein the ultrasonic probe is
configured to deliver ultrasonic energy at a frequency of at least
20 kHz to a dermal-fat junction.
18. The system of claim 1, wherein the ultrasonic probe is
configured to deliver ultrasonic energy at a frequency between 20
kHz and 100 kHz to a dermal-fat junction.
Description
[0001] This application is a divisional of U.S. application Ser.
No. 13/192,023, filed Jul. 27, 2011, which claims priority under 35
U.S.C. .sctn.119 to U.S. Provisional Application No. 61/368,354,
filed Jul. 28, 2010, both of which are incorporated herein by
reference in their entirety.
[0002] Human and animal tissues can be used to produce a variety of
tissue products for patient use. When tissues are procured from
tissue banks or animal sources, the tissues must be separated from
unnecessary or undesired adjacent tissues. However, separation of
certain tissues can be time consuming and difficult. In addition,
the desired tissue components can be damaged during the separation
process, especially if sharp instruments or high-energy devices are
used.
[0003] Accordingly, there is a need for improved methods for
dissecting tissues that can be used in production of medical
devices, such as acellular tissue matrices.
SUMMARY
[0004] According to certain embodiments, a method for dissecting
tissues is provided. The method comprises selecting a tissue site
comprising dermis and subdermal fat connected to the dermis, and
applying ultrasonic energy to the tissue to remove at least a
portion of the subdermal fat from the dermis, wherein the
ultrasonic energy is applied to minimize damage to the dermis.
DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates a device for dissecting tissues to remove
subdermal fat from dermis, according to certain embodiments.
DESCRIPTION OF CERTAIN EXEMPLARY EMBODIMENTS
[0006] Reference will now be made in detail to the certain
exemplary embodiments according to the present disclosure, certain
examples of which are illustrated in the accompanying drawings.
Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.
[0007] In this application, the use of the singular includes the
plural unless specifically stated otherwise. In this application,
the use of "or" means "and/or" unless stated otherwise.
Furthermore, the use of the term "including", as well as other
forms, such as "includes" and "included", is not limiting. Any
range described herein will be understood to include the endpoints
and all values between the endpoints.
[0008] The section headings used herein are for organizational
purposes only and are not to be construed as limiting the subject
matter described. All documents, or portions of documents, cited in
this application, including but not limited to patents, patent
applications, articles, books, and treatises, are hereby expressly
incorporated by reference in their entirety for any purpose.
[0009] Human and animal tissues can be used to produce a variety of
tissue products for patient use. For example, human and animal
dermis can be used to produce a variety of useful medical devices
or tissue products. Such products can include, for example,
reconstituted skin grafts and acellular tissue matrix products.
Examples of such acellular tissue matrix products include
ALLODERM.RTM., which is a freeze-dried acellular human dermal
tissue matrix, CYMETRA.RTM., a particulate acellular human dermal
tissue matrix, and STRATTICE.TM., a porcine acellular dermal
matrix, all of which are produced by LifeCell Corporation,
Branchburg, N.J.
[0010] When tissues are procured from tissue banks or animal
sources, the tissues must be separated from unnecessary or
undesired adjacent tissues. For example, dermis is naturally
attached to underlying fat and/or other tissues, which must be
removed to produce dermal products such as acellular tissue
matrices. However, dissecting subdermal fat free from dermis can be
difficult and time consuming. In addition, typical methods for
removal of fat, such as cutting with relatively sharp instruments,
can damage the desired dermal materials, thereby making the
materials less suitable for their intended use. Development of
methods for faster, more reliable removal of subdermal fat from
dermis are needed.
[0011] The present disclosure provides a method for dissecting
tissues. As used herein "dissecting tissues" will refer to
separating tissues that are connected into two pieces. "Dissecting
tissues" does not necessarily mean that two tissue types, e.g., fat
and dermis, are perfectly separated along an actual tissue plane.
In certain embodiments, the method includes selecting a tissue site
comprising dermis and subdermal fat connected to the dermis.
Ultrasonic energy is applied to the tissue to remove at least a
portion of the subdermal fat from the dermis, wherein the
ultrasonic energy is applied to minimize damage to the dermis.
[0012] In certain embodiments, all or part of the subdermal fat is
removed. For example, in order to provide tissues suitable for
production of acellular tissue matrices or other products, it may
be desirable to remove all or nearly all the subdermal fat.
However, removal of the fat that is very close to the dermis may
increase the risk of damage to the dermis through mechanical or
thermal means. Accordingly, in some embodiments, the ultrasonic
energy is applied to remove most of the fat, but it will be
understood that a small amount of fat may remain. Thus, in certain
embodiments, at least 70%, 80%, 90%, 95%, 99%, 99.5% (or any value
inbetween) of the subdermal fat is removed from the dermis.
[0013] The ultrasonic energy may be applied using a number of
different ultrasonic delivery systems. FIG. 1 illustrates a device
10 for dissecting tissues 20 to remove subdermal fat 30 from dermis
40, according to certain embodiments. As shown, the device includes
an ultrasound probe 50 with a tip 60 that delivers energy to
subdermal fat 30 or a dermal-fat junction 35. The ultrasound probe
will include an ultrasonic actuator (e.g., a piezoelectric
actuator), which can be controlled by an energy control system 70
to control various ultrasound process parameters.
[0014] The method of dissecting can be performed on tissue that is
present on a human cadaver or animal or on tissue that has been
separated from the cadaver or animal source. For example, in some
embodiments, the subdermal fat and dermis have been cut free of a
cadaver to form a sheet of tissue 20. As shown in FIG. 1, the sheet
20 can be laid flat on a cooling surface 80 during dissection.
Ultrasonic energy is passed through a probe to the dermal-subdermal
fat junction. Subdermal fat is rapidly separated from dermis while
keeping the dermal temperature below 50.degree. C. (e.g., by
contact with a cooling surface or cold fluid). In another example,
the dermis and subdermal fat are not removed from a cadaver. The
cadaver can be in contact with a cold fluid or wrapped in a cooling
jacket or other flexible structure during dissection to prevent
heating the dermis above 50.degree. C. Ultrasonic energy is passed
through a probe to the dermal-subdermal fat junction. Dermis is
rapidly separated from subdermal fat on the cadaver.
[0015] Various ultrasound process parameters can be controlled to
optimize the dissection process. For example, certain parameters
can be modified to improve speed, reduce heat generation/control
heating of dermal tissue, and/or to improve fat removal. For
instance, in various embodiments, the probe amplitude, frequency,
tip area, probe shape, electrical waveform (continuous or pulsed)
can be controlled. In certain embodiments, a blunt probe is used.
In some embodiments, the ultrasound properties are selected such
that the energy selectively fragments fat without fragmenting
dermis.
[0016] Typical frequencies for ultrasonic dissection tools are
20-60 kHz. However, those frequencies and power densities are
generally used for surgical applications on patients. The
frequencies and power densities may be varied for dissection of
tissues on cadavers or for tissues which have been removed from
cadavers in order to optimize cutting speed, and/or reduce or
prevent damage to dermal tissue, as desired. In various
embodiments, high power densities (e.g., higher than may be used on
a living patient) can be used to speed tissue dissection. The
higher power densities may be possible due to cooling of the tissue
before and/or during dissection, thereby preventing thermal damage.
In various embodiments, ultrasonic frequencies of at least 20 kHz
are used to dissect dermis from subdermal fat. In further
embodiments, at least 40 kHz, at least 60 kHz, at least 70 kHz, at
least 80 kHz, at least 90 kHz, or at least 100 kHz frequencies are
used. In certain embodiments, the use of frequencies above 60 kHz
enables faster dissection of subdermal fat from dermis than would
be possible in dissection from a living tissue host.
[0017] In yet further embodiments, cooling is used to keep the
temperature of the dermis and subdermal fat below 50.degree. C.
when using the at least 40 kHz, at least 60 kHz, at least 70 kHz,
at least 80 kHz, at least 90 kHz, or at least 100 kHz ultrasonic
frequencies. In still further embodiments, the cooling is by
irrigation with a cooling fluid. In still further embodiments, when
the tissue is still attached to a cadaver, cooling can be performed
by passing cooling fluid through a cooling jacket or other flexible
structure laid on and/or under the cadaver. In other embodiments,
where the dermis and subdermal fat have been removed from the
cadaver prior to dissection of subdermal fat, cooling can be
performed by laying the tissue on a cooling surface.
[0018] The ultrasonic energy may be configured to dissect fat using
a variety of mechanisms. For example, in various embodiments, the
ultrasonic energy is applied to cut, melt, or emulsify fat. In
certain embodiments, the probe size, width, and shape are selected
to optimize the desired dissection method (e.g., a sharp/wide probe
may be used for cutting subdermal fat from dermis while delivering
ultrasonic energy along a wide surface area to increase the speed
of dissection). In certain embodiments, the probe is capable of
delivering ultrasonic energy of variable frequencies and power
densities to the dermal-subdermal fat junction. In further
embodiments, the probe is capable of delivering at least 40 kHz, at
least 60 kHz, at least 70 kHz, at least 80 kHz, at least 90 kHz, or
at least 100 kHz ultrasonic frequencies. In various embodiments, a
wide probe is used to deliver ultrasonic energy across a wide
surface area. In further embodiments, the wide surface area serves
to increase the speed of dissection by emulsifying or melting more
fat simultaneously across the wide surface area. In still further
embodiments, a wide, blunt probe is used. The wide, blunt probe
emulsifies and/or melts fat immediately in front of the probe,
allowing the probe to continue advancing rapidly along the plane of
the dermis-subdermal fat junction until the dermis has been fully
separated from the subdermal fat.
[0019] Ultrasonic dissection tools can generate heat, and in some
embodiments, may be configured to melt subdermal fat to assist in
fat removal. However, excessive heating may damage the adjacent
dermis, thereby making part of the dermis unsuitable for use as an
acellular tissue matrix or other tissue product. Accordingly, in
certain embodiments, the ultrasonic energy is applied to remove fat
without causing excessive heating of the dermis. In various
embodiments, the dermis reaches a maximum temperature and heating
time that does not damage the dermal extracellular matrix of the
skin. In further embodiments, the dermis is substantially undamaged
by ultrasonic heating during separation of subdermal fat, as
compared to un-harvested dermis (i.e., the dermis retains most of
the physiological properties and structural integrity of
un-harvested dermis). In certain embodiments, either a portion or
all of the dermis is heated to no more than 50.degree. C., no more
than 45.degree. C., or no more than 40.degree. C. (or any
temperature inbetween). Further, the degree of heating that is
permissible may vary based on the tissue source (e.g., human versus
pig) and the intended application. Accordingly, in various
embodiments, the temperature is controlled to prevent heating of
any or part of the dermis that may cause unacceptable alteration in
collagen or other extracellular matrix proteins (e.g., by causing
excessive denaturation or other damage).
[0020] In some embodiments, to prevent excessive heating of dermis
while allowing rapid removal of fat, the dermis may be cooled
during application of the ultrasonic energy. In certain
embodiments, the dermis is cooled prior to application of
ultrasonic energy, e.g., the dermis is cooled to at or near
freezing temperatures. Cooling can be effectuated in a number of
ways. For example, in some embodiments, cooling is performed by
contacting the dermis with a cold surface 80, as shown in FIG. 1.
Contact with the cold surface establishes a thermal gradient
through the dermal tissue, cooling the tissue as it is heated by
the ultrasonic energy, and thereby preventing the dermis from
burning when ultrasonic energy is applied. In other embodiments,
e.g., when the tissue is still attached to a cadaver or animal, the
dermis may be cooled by irrigating the epidermal side of the tissue
with cooling fluid, and/or supplying irrigation to the ultrasound
probe site. In addition, cooling fluid may be provided using a
cooling jacket, wherein a cooled fluid is passed through a flexible
structure that can be laid on or under the dermis to continuously
cool the tissue during application of ultrasonic energy. In some
embodiments, all or part of the tissue is frozen before application
of ultrasonic energy.
* * * * *