U.S. patent application number 16/845193 was filed with the patent office on 2020-07-30 for methods of determining tissue viability.
The applicant listed for this patent is Covidien LP. Invention is credited to Patrick MOZDZIERZ.
Application Number | 20200237237 16/845193 |
Document ID | 20200237237 / US20200237237 |
Family ID | 1000004750482 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200237237 |
Kind Code |
A1 |
MOZDZIERZ; Patrick |
July 30, 2020 |
METHODS OF DETERMINING TISSUE VIABILITY
Abstract
A method of performing a surgical procedure includes generating
an infrared image of tissue using a thermographic camera, analyzing
the infrared images to determine blood flow characteristics of the
tissue, and resecting a portion of the tissue determined to have
abnormal blood flow characteristics.
Inventors: |
MOZDZIERZ; Patrick;
(Glastonbury, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covidien LP |
Mansfield |
MA |
US |
|
|
Family ID: |
1000004750482 |
Appl. No.: |
16/845193 |
Filed: |
April 10, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15439032 |
Feb 22, 2017 |
10638944 |
|
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16845193 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/7278 20130101;
A61B 2018/00184 20130101; A61B 2560/0462 20130101; A61B 2018/00904
20130101; A61B 2017/00115 20130101; A61B 5/0084 20130101; A61B
2090/065 20160201; A61B 34/30 20160201; A61B 18/00 20130101; A61B
1/3132 20130101; A61B 2018/00982 20130101; A61B 5/6843 20130101;
A61B 2018/00791 20130101; A61B 2017/00022 20130101; A61B 2562/063
20130101; A61B 5/4836 20130101; A61B 2018/0091 20130101; A61B
2018/00494 20130101; A61B 2017/00057 20130101; A61B 5/0053
20130101; A61B 5/015 20130101; A61B 5/026 20130101; A61B 5/742
20130101; A61B 5/0059 20130101; A61B 5/0261 20130101; A61B 5/6847
20130101; A61B 2018/00863 20130101; A61B 2505/05 20130101; A61B
5/1459 20130101; A61B 17/29 20130101; A61B 2018/005 20130101; A61B
5/022 20130101; A61B 2018/00005 20130101; A61B 5/02055
20130101 |
International
Class: |
A61B 5/026 20060101
A61B005/026; A61B 5/00 20060101 A61B005/00; A61B 34/30 20060101
A61B034/30; A61B 5/022 20060101 A61B005/022; A61B 17/29 20060101
A61B017/29; A61B 18/00 20060101 A61B018/00; A61B 5/0205 20060101
A61B005/0205; A61B 5/01 20060101 A61B005/01 |
Claims
1. A method of performing a surgical procedure, comprising:
generating an infrared image of subject tissue of a patient using a
thermographic camera; analyzing the infrared image to determine
blood flow characteristics of the subject tissue; and resecting a
portion of the subject tissue determined to have abnormal blood
flow characteristics.
2. The method according to claim 1, further comprising stapling the
subject tissue upon determining that the subject tissue has normal
blood flow characteristics.
3. The method according to claim 1, further comprising comparing
the infrared image of the subject tissue with an infrared image of
healthy tissue to determine whether the subject tissue exhibits
normal blood flow characteristics.
4. The method according to claim 1, further comprising: generating
an infrared image of tissue known to be healthy using the
thermographic camera; and comparing the infrared image of the
tissue known to be healthy with the infrared image of the subject
tissue to determine whether the subject tissue exhibits normal
blood flow characteristics.
5. The method according to claim 1, wherein the thermographic
camera is a thermographic endoscope.
6. The method according to claim 1, wherein analyzing the infrared
image to determine blood flow characteristics of the subject tissue
includes determining a rate at which the subject tissue returns to
a baseline temperature from a temperature below the baseline
temperature.
7. The method according to claim 6, further comprising reducing a
temperature of the subject tissue from the baseline temperature to
the temperature below the baseline temperature by contacting the
subject tissue with pre-chilled tissue contacting surfaces of a
tissue grasper.
8. The method according to claim 1, further comprising determining
a local perfusion pressure of the subject tissue by applying
pressure to the subject tissue using a tissue grasper.
9. The method according to claim 8, further comprising: determining
a systemic blood pressure of the patient; calculating a first index
using the determined local perfusion pressure and the determined
systemic blood pressure; and determining viability of the subject
tissue based on the first index and the determined blood flow
characteristics of the subject tissue.
10. The method according to claim 1, wherein the subject tissue is
a pair of bowel segments.
11. The method according to claim 10, further comprising
determining that ends of the pair of bowel segments have normal
blood flow characteristics.
12. The method according to claim 11, further comprising stapling
the ends of the pair of bowel segments to reconnect the pair of
bowel segments after determining that the ends of the pair of bowel
segments have normal blood flow characteristics.
13. The method according to claim 12, wherein determining that the
ends of the pair of bowel segments have normal blood flow
characteristics includes analyzing the infrared image to determine
whether the ends of the pair of bowel segments exhibit normal heat
distribution characteristics.
14. A method of performing a surgical procedure, comprising:
applying pressure to a subject tissue; removing the pressure
applied to the subject tissue; generating an infrared image of the
subject tissue using a thermographic camera after removing the
pressure applied to the subject tissue; observing a rate at which
the subject tissue increases in temperature using the infrared
image; and determining whether the subject tissue increases in
temperature at a rate associated with healthy tissue.
15. The method according to claim 14, further comprising resecting
a portion of the subject tissue that increases in temperature at a
rate associated with unhealthy tissue.
16. The method according to claim 14, further comprising stapling
the subject tissue upon determining that the subject tissue
increases in temperature at the rate associated with healthy
tissue.
17. The method according to claim 14, further comprising reducing a
temperature of the subject tissue prior to generating the infrared
image of the subject tissue.
18. The method according to claim 17, wherein the pressure is
applied to the subject tissue using a tissue grasper and the
temperature of the subject tissue is reduced by contacting the
subject tissue with pre-chilled tissue-contacting surfaces of the
tissue grasper.
19. The method according to claim 14, wherein the subject tissue is
a pair of bowel segments, the method further comprising resecting a
portion of at least one of the pair of bowel segments upon
determining that the portion of at least one of the pair of bowel
segments increases in temperature at the rate associated with
unhealthy tissue.
20. The method according to claim 19, further comprising stapling
ends of the pair of bowel segments to reconnect the pair of bowel
segments upon determining that the ends of the pair of bowel
segments increase in temperature at the rate associated with
healthy tissue.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Divisional application of U.S. patent
application Ser. No. 15/439,032, filed on Feb. 22, 2017, the entire
contents of which being incorporated by reference herein.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to medical procedures and,
more particularly, to procedures for determining and monitoring
characteristics of tissue in preparation for performing various
surgical procedures.
2. Background of Related Art
[0003] Colorectal surgery sometimes requires anastomosis, which
involves resecting a piece of diseased bowel tissue and creating a
new connection between two presumably healthy bowel segments.
Typically, before performing the anastomosis, the amount of tissue
to be resected is estimated using visual indicia of the bowel. The
goal is to preserve as much healthy tissue as possible while at the
same time removing all of the diseased tissue.
[0004] A risk involved in performing an anastomotic procedure is
anastomotic leaks typically caused by a failure to resect all of
the diseased tissue. Current methods used in estimating the amount
of tissue to be resected during an anastomotic procedure are
sometimes inadequate in preventing all anastomotic leaks.
Additionally, the health and viability of colon and bowel sections
may be compromised by excessive tension or insufficient blood flow
in the newly attached sections.
[0005] Accordingly, a need exists for surgical instruments that can
sense and visualize, either sequentially or simultaneously, a
multitude of parameters and factors of the bowel tissue to aid a
surgeon in performing a more successful anastomotic surgical
procedure.
SUMMARY
[0006] In one aspect of the present disclosure, a method of
performing a surgical procedure is provided and includes generating
an infrared image of subject tissue using a thermographic camera,
analyzing the infrared images to determine blood flow
characteristics of the subject tissue, and resecting a portion of
the subject tissue determined to have abnormal blood flow
characteristics.
[0007] In some embodiments, the method may further include stapling
the subject tissue upon determining that the subject tissue has
normal blood flow characteristics.
[0008] In some embodiments, the method may further include
comparing the infrared image of the subject tissue with an infrared
image of healthy tissue to determine whether the subject tissue
exhibits normal blood flow characteristics.
[0009] In some embodiments, the method may further include
generating an infrared image of tissue known to be healthy using
the thermographic camera, and comparing the infrared image of the
tissue known to be healthy to determine whether the subject tissue
exhibits normal blood flow characteristics.
[0010] In some embodiments, the thermographic camera may be a
thermographic endoscope.
[0011] In another aspect of the present disclosure, a method of
performing a surgical procedure is provided and includes applying
pressure to a subject tissue, removing the pressure applied to the
subject tissue, generating an infrared image of the subject tissue
using a thermographic camera after removing the pressure applied to
the subject tissue, observing a rate at which the subject tissue
increases in temperature using the infrared image, and determining
whether the subject tissue increases in temperature at a rate
associated with healthy tissue.
[0012] In some embodiments, the method may further include
resecting a portion of the subject tissue that increases in
temperature at a rate associated with unhealthy tissue.
[0013] In some embodiments, the method may further include stapling
the subject tissue upon determining that the subject tissue
increases in temperature at the rate associated with healthy
tissue.
[0014] In some embodiments, the method may further include reducing
a temperature of the subject tissue prior to generating the
infrared image of the subject tissue. The pressure may be applied
to the subject tissue using a tissue grasper and the temperature of
the subject tissue is reduced by contacting the subject tissue with
pre-chilled tissue-contacting surfaces of the tissue grasper.
[0015] In yet another aspect of the present disclosure, a method of
performing a surgical procedure is provided and includes
determining a local perfusion pressure of subject tissue of a
patient, determining a systemic blood pressure of the patient,
calculating a first index using the determined local perfusion
pressure and the determined systemic blood pressure, generating an
infrared image of the subject tissue using a thermographic camera,
analyzing the infrared image to determine blood flow
characteristics of the subject tissue, and determining viability of
the subject tissue based on the first index and the determined
blood flow characteristics of the subject tissue.
[0016] In some embodiments, the method may further include
assigning a numerical value to the tissue based on the determined
blood flow characteristics, and calculating a second index using
the first index and the assigned numerical value to the determine
the viability of the subject tissue. The second index may be
compared to a known index corresponding to viable tissue.
[0017] In some embodiments, determining the local perfusion
pressure may include applying pressure to the tissue using a tissue
grasper. The method may further include reducing a temperature of
the subject tissue prior to generating the infrared image of the
subject tissue. The temperature of the subject tissue may be
reduced by contacting the subject tissue with pre-chilled
tissue-contacting surfaces of the tissue grasper.
[0018] In some embodiments, the method may further include stapling
the subject tissue upon determining that the subject tissue is
viable.
[0019] In some embodiments, the method may further include
observing a rate at which the subject tissue increases in
temperature using the infrared image, and determining whether the
subject tissue increases in temperature at a rate associated with
healthy tissue.
[0020] In some embodiments, the method may further include
comparing the infrared image of the subject tissue with an infrared
image of healthy tissue to determine whether the subject tissue
exhibits normal blood flow characteristics.
[0021] In some embodiments, the method may further include
generating an infrared image of tissue known to be healthy using
the thermographic camera, and comparing the infrared image of the
tissue known to be healthy to determine whether the subject tissue
exhibits normal blood flow characteristics.
[0022] These and other objects will be more clearly illustrated
below by the description of the drawings and the detailed
description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of
the present disclosure and, together with the detailed description
of the embodiments given below, serve to explain the principles of
the disclosure.
[0024] FIG. 1 is a front, perspective view of a surgical system
including a surgical instrument and a thermographic camera, in
accordance with the present disclosure;
[0025] FIG. 2 is a flow chart depicting a method of using the
thermographic camera of the surgical system of FIG. 1 to assess
tissue viability;
[0026] FIG. 3 is a flow chart depicting another method of using the
thermographic camera of the surgical system of FIG. 1 to assess
tissue viability;
[0027] FIG. 4 is a flow chart depicting a method of using the
thermographic camera in conjunction with the surgical instrument of
the surgical system of FIG. 1 to assess tissue viability;
[0028] FIG. 5 is a rear, perspective view of the surgical
instrument of the surgical system of FIG. 1;
[0029] FIG. 6 is an enlarged view of a handle portion of the
surgical instrument of FIG. 5 illustrating a display of the
surgical instrument;
[0030] FIG. 7 is an enlarged view of the display of the surgical
instrument of FIG. 5;
[0031] FIG. 8 is an enlarged view of a jaw assembly of the surgical
instrument of FIG. 5 illustrating sensors incorporated therein;
[0032] FIG. 9 is a top view of the surgical instrument of FIG. 5
illustrating the jaw assembly grasping tissue; and
[0033] FIG. 10 is a flow chart depicting another method of using
the thermographic camera of FIG. 1 in conjunction with the surgical
instrument of FIG. 5 to assess tissue viability.
DETAILED DESCRIPTION
[0034] Embodiments of the presently disclosed surgical systems and
methods of use will now be described in detail with reference to
the drawing figures wherein like reference numerals identify
similar or identical elements. As used herein and as is
traditional, the term "distal" will refer to that portion which is
further from the clinician while the term "proximal" will refer to
that portion which is closer to the clinician.
[0035] With reference to FIG. 1, a medical diagnostic system 1 is
illustrated, which generally includes a thermographic camera for
taking infrared images of a surgical site, and a surgical
instrument, such as, for example, a tissue grasper 10 for grasping
and sensing a multiplicity of biological parameters of grasped
tissue to assist a surgeon in performing a surgical procedure, for
example, an anastomotic surgical procedure. The thermographic
camera may be a thermographic endoscope 2 capable of being used in
a minimally invasive manner. A detailed description of an exemplary
thermographic endoscope may be found in U.S. Pat. No. 5,445,157,
filed on Feb. 20, 1992, the entire contents of which are
incorporated by reference herein.
[0036] The thermographic endoscope 2 includes a shaft portion 4 and
a display 6 in communication (e.g., electrical or wireless) with
the shaft portion 4. The shaft portion 4 is dimensioned for
insertion through a surgical incision in a patient and to be
positioned adjacent the tissue to be imaged. Thermographic
endoscope 2 also includes an infrared image forming device (not
shown) disposed in a distal portion of the shaft 4 for forming an
infrared image of the tissue to be visualized, and a device (not
shown) for transmitting the infrared image formed by the infrared
image forming device to a device (not shown) for converting the
infrared image, which is transmitted by the infrared image
transmitting device into a visible image for displaying the visible
image on display 6. In some embodiments, rather than using a
thermographic endoscope, the surgical system 1 may utilize a
portable thermographic camera not intended for use in a minimally
invasive manner.
[0037] Thermographic endoscope 2 is configured to produce an image
of tissue under inspection by taking advantage of the differences
in the amount of infrared radiation emitted from different areas of
the tissue. Different parts of tissue may exhibit unique blood flow
characteristics based on various parameters of the tissue, for
example, the health of the tissue (e.g., healthy, diseased, or
necrosed), the amount and type of vasculature in the tissue, and
the particular type of tissue (e.g., colorectal tissue). The blood
flow characteristics of tissue include the rate at which tissue
recovers to a baseline temperature after having been cooled to a
selected temperature below the baseline temperature, and the rate
at which a normal blood flow returns to the tissue after having
been blocked (i.e., a perfusion rate).
[0038] As can be appreciated, due to the heat carried by blood, the
blood flow characteristics of a particular tissue are closely
correlated with the thermal profile exhibited by the tissue. As
such, the differences in blood flow characteristics of a selected
portion of tissue may be visualized using infrared imaging
techniques, for example, the thermographic endoscope 2 of surgical
system 1. Providing a clinician with a visual image or a live feed
of infrared images of tissue (e.g., colorectal tissue) indicative
of the blood flow characteristics of the tissue prior to performing
an anastomosis may assist the clinician in determining whether the
selected tissue is viable, as will be described in detail
below.
[0039] In operation, thermographic endoscope 2 may be used prior
to, during, or after a surgical procedure, for example, an
anastomotic surgical procedure, to provide a clinician with
enhanced visual data about the subject tissue. In an anastomotic
surgical procedure, unhealthy or diseased bowel tissue is resected
and the ends of the remaining healthy segments of bowel are
reconnected using one of a variety of anastomosis techniques,
including, but not limited to, end to end stapler anastomosis, hand
sewn anastomosis, and linear stapled anastomosis. Prior to
reconnecting the ends of the separate bowel segments to one another
using any of the above-noted anastomosis techniques, the viability
of the ends of the separate bowel segments should be assessed in
order to predict the likelihood of post-surgery anastomotic leaks
or other adverse outcomes. To aid in making this viability
assessment, a clinician may make use of thermographic endoscope 2
of the present disclosure.
[0040] With reference to FIG. 2, a use of thermographic endoscope 2
will be described. In use, each of the two ends of the presumably
healthy bowel segments are imaged using the thermographic endoscope
2 by positioning the infrared image forming device (not shown)
thereof adjacent the bowel segments. In step 102, the infrared
image forming device forms an infrared image of the tissue, which
is then converted and transmitted into a visible image or live feed
of infrared images "IR" displayed on display 14. In step 104, the
clinician analyzes the video feed of infrared images "IR" to
determine whether the tissue exhibits normal heat distribution
characteristics (e.g., a uniform heat profile throughout the imaged
tissue). If the clinician determines that the tissue exhibits
normal heat distribution characteristics, the clinician continues
to step 106, which includes stapling the two ends of the bowel
segments, thereby completing the anastomosis. Alternatively, if the
clinician determines that the tissue exhibits abnormal heat
distribution characteristics (e.g., a non-uniform heat profile
throughout the imaged tissue), the clinician continues to step 108,
which includes resecting a portion of the tissue exhibiting
abnormal heat distribution characteristics. This process will have
to be repeated until all of the tissue is shown to exhibit normal
heat distribution characteristics.
[0041] An experienced clinician may be able to determine whether
the tissue is healthy based on the infrared images "IR" alone, as
described with reference to the flow chart of FIG. 2. However, with
reference to FIG. 3, additional steps may be taken to assist the
clinician in determining whether the subject tissue exhibits normal
heat distribution characteristics.
[0042] In particular, in step 202, tissue that is known to be
healthy may be simultaneously imaged using the thermographic
endoscope 2, or in some embodiments, any suitable thermographic
camera, to display infrared images of the known-to-be healthy
tissue on the display 14 in juxtaposed relation to the infrared
images "IR" of the subject tissue. In this way, in step 204, the
clinician may compare the infrared images of the known-to-be
healthy tissue and the subject tissue to determine the degree of
similarity between their heat profiles. In step 206, the clinician
determines whether the subject tissue is healthy based on the
visual comparison of the infrared images "IR" of the subject tissue
with the infrared images of the known-to-be healthy tissue.
[0043] In one embodiment, upon assessing the infrared images "IR"
of the subject tissue, the clinician may assign a numerical value
to the subject tissue based on how close the heat distribution of
the subject tissue corresponds to the heat distribution found in
the known-to-be healthy tissue. For example, based on the infrared
images "IR," the clinician may assign the tissue a numerical value
ranging from 1 to 100, 1 to 50, 1 to 10, or 1 to 5, wherein the
lowest numerical value (e.g., 1) equates to necrosed/diseased
tissue, and the highest numerical value (e.g., 100) equates to
ideally healthy/viable tissue. As such, a clinician can use this
number, determined using the infrared images "IR" of the subject
tissue, to make a determination on whether the two ends of the
bowel segments are healthy enough to be reconnected or whether more
tissue needs to be resected. If the clinician determines that the
tissue exhibits normal heat distribution characteristics, the
clinician continues to step 208, which includes reconnecting the
two ends of the bowel segments, thereby completing the anastomosis.
Alternatively, if the clinician determines that the tissue exhibits
abnormal heat distribution characteristics compared to the
known-to-be healthy tissue, the clinician continues to step 210,
which includes resecting a portion of the tissue exhibiting
abnormal heat distribution characteristics. This process will have
to be repeated until all of the tissue is shown to exhibit normal
heat distribution characteristics compared to the known-to-be
healthy tissue.
[0044] With reference to FIG. 4, manipulation of the subject tissue
prior to and/or during an analysis of the infrared images "IR" of
the subject tissue may further assist the clinician in gathering
information about the subject tissue. For example, the infrared
images "IR" generated using the thermographic endoscope 2 may be
taken after performing a grasp-then-release method on the tissue to
assess tissue perfusion. In particular, in step 302, the bowel
segments may be grasped, either separately or together, using any
suitable device (e.g., tissue grasper 10) capable of applying a
clamping pressure on the tissue sufficient to prevent or
substantially prevent blood from flowing through the grasped
tissue. Clamping the tissue in this way removes a substantial
amount of blood from each of the two ends of bowel segments,
thereby bringing each portion of the subject tissue to the
substantially same temperature, in effect calibrating the tissue.
In step 304, in the instance where tissue grasper 10 is used to
clamp the tissue, the tissue may be cooled by pre-chilling the
tissue-contacting surfaces 54, 56 of tissue grasper 10 and grasping
the tissue between the pre-chilled tissue contacting-surfaces 54,
56 of tissue grasper 10.
[0045] Upon the ceasing of blood flow through the grasped tissue
and/or the cooling of the grasped tissue from the pre-chilled
tissue-contacting surfaces 54, 56 of tissue grasper 10,
thermographic endoscope 2 is positioned so that the infrared image
forming device of thermographic endoscope 2 is facing the grasped
tissue. In step 306, the clamping pressure on the tissue is removed
to allow for blood flow to return to the tissue to gradually
restore the temperature of the tissue to its initial value or
baseline temperature. This grasp-and-release step allows for a more
accurate determination of the heat profile of the subject
tissue.
[0046] In step 308, a video feed of infrared images taken by
thermographic endoscope 2 of the subject tissue will be displayed
on display 14 beginning at the time the clamping pressure on the
tissue is released. As the blood begins to return to the tissue,
the amount of infrared radiation emitted by the tissue will
increase at a rate correlated with the health of the tissue. For
example, if the tissue is healthy, tissue perfusion should occur at
a rate that is known for healthy tissue of the type being studied.
Accordingly, the infrared images "IR" taken by thermographic
endoscope 2 would indicate that the tissue increased in temperature
(due to blood flowing therethrough) at a rate substantially similar
or the same as that known for healthy tissue. Alternatively, if the
tissue is not healthy or not viable, tissue perfusion should occur
at a rate less than expected for otherwise healthy tissue of the
particular type being studied. Accordingly, the infrared images
"IR" taken by thermographic endoscope 2 would indicate that the
tissue increased in temperature (due to blood flowing therethrough)
at a rate less than that known for otherwise healthy tissue. As
such, in step 310, the clinician visually observes the rate at
which the subject tissue increases in temperature using the
infrared images "IR" to determine whether the subject tissue
increases in temperature at a normal rate.
[0047] An experienced clinician may be able to determine whether
the tissue is healthy based solely on the rate of thermal change of
the tissue visually observed from the infrared images "IR."
However, to assist the clinician in determining whether the subject
tissue exhibits a normal rate of thermal change, a measurement may
be taken of the time it takes for the tissue to return to its
initial, baseline temperature. This measured time may be compared
to an index containing a list of known times each corresponding to
a different degree of viability of tissue of the type being
studied. For example, if healthy bowel tissue is known to typically
take approximately 5 seconds to warm up naturally to its baseline
temperature after being chilled to 5 degrees Fahrenheit below its
baseline temperature; and the bowel tissue being studied was
measured to take approximately 10 seconds, this information can be
used by the clinician to determine that the subject tissue may not
be viable. As such, a clinician can use this information,
determined using the infrared images "IR" of the subject tissue, to
make a determination on whether the two ends of the bowel segments
are healthy enough to be reconnected or whether more tissue needs
to be resected. If the clinician determines that the tissue returns
to its baseline temperature at a normal rate, the clinician
continues to step 312, which includes stapling the two ends of the
bowel segments, thereby completing the anastomosis. Alternatively,
if the clinician determines that the tissue returns to its baseline
temperature at an abnormal rate (e.g., faster or slower than that
expected), the clinician continues to step 314, which includes
resecting a portion of the tissue exhibiting an abnormal rate of
thermal change. This process will have to be repeated until all of
the tissue is shown to exhibit normal rates of thermal change.
[0048] As will be described below, the above-described methods of
using thermographic imaging to assess tissue viability may be used
in combination with other measurements taken of the patient, for
example, a local perfusion pressure reading and/or a systemic blood
pressure reading, to provide an even more accurate assessment of
tissue viability.
[0049] With reference to FIGS. 1A and 5-10, surgical system 1 may
further include tissue grasper 10, which is configured to grasp
tissue and sense a multiplicity of biological parameters of the
grasped tissue to assist a surgeon in performing a surgical
procedure, for example, an anastomotic surgical procedure. The
tissue grasper 10 generally includes a handle portion 12, an
elongated shaft 30, and a jaw assembly 40.
[0050] The handle portion 12 of the tissue grasper 10 includes a
stationary handle 14 and a pivoting or movable handle 16 pivotably
coupled to the stationary handle 14. Manipulation of the pivoting
handle 16 relative to the stationary handle 14 effects a closing of
the jaw assembly 40 to grasp tissue. The handle portion 12 of the
tissue grasper 10 includes a longitudinal body portion 18 formed
with the stationary handle 14. The body portion 18 has a display
20, for example, an LED display or liquid-crystal display ("LCD")
for displaying various tissue parameters measured by various
sensors 42a-c, 44a-c of the tissue grasper 10.
[0051] With reference to FIGS. 6 and 7, the body portion 18 of the
handle portion 12 defines a longitudinal axis "X" that is coaxial
with a longitudinal axis defined by the elongated shaft 30. The
body portion 18 has a planar upper surface 22 on which the display
20 is situated. It is contemplated that the display 20 may be
disposed at any suitable location of the body portion 18 or on any
other component of the tissue grasper 10.
[0052] The display 20 may have multiple display sections, for
example, three display sections 20a, 20b, 20c, arranged in a linear
array along the longitudinal axis "X." It is contemplated that the
display 20 may include more or less than three discrete display
sections. A first display section 20a of the display 20 is
configured to display a visual indication of a measured tissue
perfusion of tissue grasped by the tissue grasper 10. A second
display section 20b of the display 20 is configured to display a
visual indication of a measured amount of pressure being applied to
tissue grasped by the tissue grasper 10. A third display section
20c of the display 20 is configured to display a measured thickness
of the tissue grasped by the tissue grasper 10.
[0053] The visual indication displayed by each of the display
sections 20a, 20b, 20c includes a range of colors increasing in
brightness from a proximal portion to a distal portion thereof. For
example, when viewing each of the first and second display sections
20a, 20b in a proximal to distal direction, the first and second
display sections 20a, 20b may each be green, yellow, orange, and
then red, with each color portion gradually blending into the
adjacent color portion. Other colors and color arrangements for the
first and second display sections 20a, 20b are contemplated. The
tissue grasper 10 may be configured such that when the green of the
first display section 20a is lit, this may indicate a relatively
high tissue perfusion being measured by the tissue grasper 10,
whereas when the red of the first display section 20a is lit, this
may indicate a relatively low tissue perfusion being measured by
the tissue grasper 10. The information related to the tissue
perfusion may be useful when making a determination on the
viability of the tissue being grasped, as will be described in more
detail below.
[0054] With reference to the second display section 20b of the
display 20, when the green of the second display section 20b is
lit, this may be indicative of a relatively low grasping or
clamping pressure being applied to tissue by the tissue grasper 10,
whereas when the red of the second display section 20b is lit, this
may be indicative of a relatively high grasping or clamping
pressure being applied to tissue by the tissue grasper 10. The
clamping pressure measured by the tissue grasper 10 and displayed
by the second display section 20b of the tissue grasper 10 is used
in conjunction with the tissue perfusion displayed by the first
display section 20a of the tissue grasper 10 to determine the
perfusion pressure of the grasped tissue.
[0055] The perfusion pressure is measured by applying a sufficient
amount of clamping pressure on the subject tissue until there is no
perfusion (i.e., no blood flow) through the tissue, and then slowly
reducing the clamping pressure until perfusion through the grasped
tissue restarts. The pressure at which the perfusion restarts is
the tissue perfusion pressure. For a detailed description of a
method of measuring surface perfusion pressure, reference may be
made to U.S. Pat. No. 7,618,376, the entire contents of which are
incorporated by reference herein.
[0056] The information related to the amount of pressure being
applied to tissue by the tissue grasper 10 may also be useful in
preventing over-compression of tissue to prevent damage to healthy
tissue.
[0057] In viewing the third display section 20c from a proximal to
distal direction, the third display section 20c may be grey, brown,
violet, and black. In some embodiments, third display section 20c
may be grey, white, blue, purple, tan, green, and black. Other
colors and color arrangements for the third display section 20c are
contemplated. When the grey (proximal portion) of the third display
section 20c is lit, this may be an indication that tissue grasped
by the tissue grasper 10 has a relatively small thickness (i.e.,
the tissue is too thin to withstand being reconnected), whereas
when the black (distal portion) of the third display section 20c is
lit, this may be an indication that tissue grasped by the tissue
grasper 10 has a relatively large thickness (i.e., the tissue is
too thick to be reconnected). The information related to tissue
thickness may be useful for making a determination on the type of
reconnection technique to be used. Where stapling is selected, the
information can be useful in selecting the size of the staples to
be used when performing a surgical anastomosis on the grasped
tissue.
[0058] In some embodiments, instead of display 20 utilizing ranges
of colors or brightness to illustrate the measured tissue
parameters (e.g., tissue perfusion, tissue compression, and tissue
thickness), the display 20 may display ranges of numbers or various
numeral outputs. In particular, the first, second, and third
display sections 20a, 20b, 20c may display the number ranges 0 to
3, 0 to 5, 0 to 10, 0 to 100, or any other suitable range, to
illustrate information about the tissue being grasped by the tissue
grasper 10. For example, when the first display section 20a
displays the number 0, this may be an indication that the grasped
tissue has very little or no perfusion (i.e., no blood flow),
whereas when the first display section 20a displays the number 100,
this may be an indication that the grasped tissue has a high
perfusion (i.e., ideal blood flow).
[0059] In some embodiments, the display 20 may illustrate
information about grasped tissue utilizing any suitable indicia,
for example, words such as poor, satisfactory, or good.
[0060] In some embodiments, tissue grasper 10 may not include
display 20, and instead, tissue grasper 10 may be configured to be
connected to or be in communication with another type of display,
for example, display 6 of thermographic endoscope 2, a tablet, a
cell phone, a computer monitor, a laptop, or any suitable display
device. Tissue grasper 10 may be connected to any of the
aforementioned display devices via USB wires, Wi-Fi, or the
like.
[0061] With reference to FIGS. 1, 5, and 8, the elongated shaft 30
of tissue grasper 10 extends distally from the handle portion 12
and houses an actuation rod (not explicitly shown). The elongated
shaft 30 may be rotatable with respect to the handle portion 12 to
rotate the jaw assembly 40 about the longitudinal axis "X." The
elongated shaft 30 has two prongs 32, 34 formed at its distal end
30b. A pivot pin 36 extends transversely through the prongs 32, 34
and the jaw assembly 40 to provide a point about which the jaw
members 42, 44 of the jaw assembly 40 pivot. The actuation rod has
a proximal end (not shown) operably coupled to the movable trigger
16 (FIGS. 1, 5), and a distal end (not shown) extending between the
prongs 32, 34 and which is operably coupled to the jaw assembly
40.
[0062] With reference to FIGS. 8 and 9, the jaw assembly 40
includes first and second juxtaposed jaw members 42, 44,
respectively, which are simultaneously movable between a
substantially approximated position, in which the jaw members 42,
44 are in relatively close relation to one another, and a spaced
position, in which the jaw members 42, 44 are separated at least a
sufficient distance to receive tissue therebetween, for example,
tissue "T." The jaw assembly 40 includes a first proximal portion
or a first flange 46 extending proximally from the first jaw member
42, and a second proximal portion or a second flange 48 extending
proximally from the second jaw member 44. The flanges 46, 48 each
include an elongated angled cam slot 50, 52 defined therethrough
configured to engage the distal end of the actuation rod (not
explicitly shown) that drives the opening and closing of the jaw
members 42, 44 as the actuation rod moves through the cam slots 50,
52. As such, manipulation of the pivoting handle 16 (FIGS. 1, 5)
relative to the stationary handle 14 actuates the actuation rod to
effect an opening or a closing of the jaw assembly 40 about tissue
"T."
[0063] With continued reference to FIGS. 8 and 9, the jaw members
42, 44 each have a tissue contacting surface 54, 56 such that when
the jaw assembly 40 is in the closed configuration, tissue "T" is
grasped between the tissue contacting surfaces 54, 56. The jaw
assembly 40 may be coupled to a cooling system (not shown)
configured to pass coolant through jaw member 42, 44 to cool tissue
contacting surfaces 54, 56 thereof. Alternatively, tissue
contacting surfaces 54, 56 may include a thermoelectric cold plate
for reducing the temperature of tissue contacting surfaces 54, 56.
Tissue contacting surfaces 54, 56 are cooled so that when tissue
contacting surfaces 54, 56 are applied to tissue, the tissue
contacting surfaces 54, 56 reduce the temperature of the tissue, as
will be described in detail below.
[0064] The jaw members 42, 44 each have a first sensor 42a, 44a, a
second sensor 42b, 44b, and a third sensor 42c, 44c, disposed on
respective tissue contacting surfaces 54, 56. The sensors 42a-c,
44a-c are arranged on respective tissue contacting surfaces 54, 56
in a linear array along a longitudinal axis defined by respective
jaw members 42, 44. In some embodiments, the sensors 42a-c, 44a-c
may be arranged on respective tissue contacting surfaces 54, 56 in
any suitable manner.
[0065] The first sensors 42a, 44a of the jaw assembly 40 are
perfusion sensors, for example, Doppler flow sensors, configured to
measure local perfusion (i.e., blood flow) through tissue grasped
between the jaw members 42, 44. The first sensors 42a, 44a may
measure perfusion of the grasped tissue on the basis of known
techniques, such as Laser-Doppler Flowmetry ("LDF"), measuring
light scattering, and/or measuring absorption of light from one or
more LED's or other light sources. For a detailed description of
LDF technology, reference may be made to U.S. Pat. Nos. 4,109,647
and 4,862,894, the entire contents of each of which are
incorporated by reference herein.
[0066] In some embodiments, only one of the tissue contacting
surfaces 54, 56 of the jaw assembly 40 has a perfusion sensor. The
first sensors 42a, 44a are in communication, via lead wires or
wireless connection, with the first display section 20a of the
display 20 such that upon the first sensors 42a, 44a measuring the
perfusion in grasped tissue, the first sensors 42a, 44a transmit
the measurement data to the first display section 20a, which
displays the measurement in any of the manners described above with
reference to FIGS. 2 and 3 (e.g., a range of colors, brightness
levels, numbers, words.)
[0067] In some embodiments, the first sensors 42a, 44a may also be
in communication, via lead wires or wireless connection, with a
computing device or processor (not shown) such as a laser Doppler
monitor, which processes the information collected by the first
sensors 42a, 44a to calculate the tissue perfusion. The computing
device may also be in communication, via lead wires or wireless
connection, with the first display section 20a to send the
processed information related to the tissue perfusion to the first
display section 20a so that the first display section 20a can
display the tissue perfusion in any of the manners described above
with reference to FIGS. 6 and 7 (e.g., colors, brightness levels,
numbers, words.)
[0068] With continued reference to FIGS. 8 and 9, the second
sensors 42b, 44b of the jaw assembly 40 are pressure sensors or
pressure measuring devices, for example, MEMS devices. For a
detailed description of various MEMS devices, reference may be made
to U.S. Pat. No. 8,808,311, the entire contents of which are
incorporated by reference herein. The second sensors 42b, 44b are
configured to measure the amount of pressure applied by the tissue
grasper 10 to the grasped tissue (i.e., the clamping pressure). In
some embodiments, only one of the tissue contacting surfaces 54, 56
has a pressure sensor. The second sensors 421, 44b are in
electrical communication, via lead wires of wireless connection,
with the second display section 20b of the display 20 such that
upon the second sensors 42b, 44b measuring the clamping pressure
applied to the grasped tissue, the second sensors 42b, 44b transmit
the measurement data to the second display section 20b, which
displays the measurement in any of the manners described above with
reference to FIGS. 6 and 7 (e.g., colors, brightness levels,
numbers, words.) Additionally or alternately, the second sensors
42b, 44b may send the measured clamping pressure to the computing
device for processing, which then sends the information to the
display 20.
[0069] The third sensors 42c, 44c of the jaw assembly 40 are gap
determination elements, for example, slide potentiometers,
rotational potentiometers, devices used to measure impedance
between the contacting surfaces 54, 56, or Linear Variable
Differential Transformers ("LVDT"), configured to measure the
thickness of the grasped tissue by measuring the gap distance
between the jaw members 42, 44. For a detailed description of
various sensors capable of measuring tissue thickness, reference
may be made to U.S. Pat. No. 8,002,795, the entire contents of
which are incorporated by reference herein, in some embodiments,
only one of the tissue contacting surfaces 54, 56 has a gap
determination element. The third sensors 42c, 44c are in electrical
communication, via wire leads or wireless connection, with the
third display section 20c of the display 20 such that upon the
third sensors 42c, 44c measuring the tissue thickness of the
grasped tissue, the third sensors 42c, 44c transmit the measurement
data to the third display section 20c, which displays the
measurement in any of the manners described above with reference to
FIGS. 6 and 7 (e.g., colors, brightness levels, numbers, words.)
Additionally or alternately, the third sensors 42c, 44c may be in
communication, via lead wires or wireless connection, to the
computing device, which receives the tissue thickness measurements
from the third sensors 42c, 44c, and processes the measurement data
and then sends the information to the display 20.
[0070] In some embodiments, the display 20 may include a fourth
display section (not shown) configured to display an index
representative of the ratio of the surface perfusion pressure
measured by first sensors 42a, 44a and second sensors 42b, 44b of
the tissue grasper 10, and a systemic blood pressure measured by a
blood pressure cuff (not shown), as will be described in detail
below.
[0071] In operation, the tissue grasper 10 may be used prior to,
during, or after a surgical procedure, for example, an anastomotic
surgical procedure, to gather various data about the subject
tissue. In an anastomotic surgical procedure, unhealthy or diseased
bowel tissue is resected and the ends of the remaining healthy
segments of bowel are reconnected. Prior to reconnecting the ends
of the separate bowel segments to one another, the viability of the
ends of the separate bowel segments should be assessed in order to
predict the likelihood of post-surgery anastomotic leaks or other
adverse outcomes. To aid in making this viability assessment, a
surgeon may make use of the tissue grasper 10 in conjunction with
the thermographic endoscope 2 (FIG. 1).
[0072] In use of the tissue grasper 10, each of the two ends of the
presumably healthy, bowel segments are grasped, either separately
or together, between the tissue contacting surfaces 54, 56 of the
jaw assembly 40. While monitoring the perfusion reading (i.e.,
blood flow) displayed on the first display section 20a of the
tissue grasper 10, the pivoting handle 16 is manipulated to
gradually increase the clamping pressure until the perfusion
reading indicates that no blood flow or virtually no blood flow is
moving through the grasped tissue. While continuously monitoring
both the first and second display sections 20a, 20b, the movable
handle 16 of the tissue grasper 10 is manipulated to gradually
reduce the amount of clamping pressure being applied to the tissue.
The clamping pressure is reduced until first display section 20a
displays a perfusion reading indicating that blood flow has
returned to the grasped tissue. At the moment that the perfusion
reading indicates that the blood flow is returned, the clamping
pressure reading displayed by the second display section 20b is
noted, which is the local perfusion pressure of the grasped tissue.
The measured local perfusion pressure may be used to assess the
viability of the grasped tissue. Additionally or alternately, the
measured local perfusion pressure may be used in combination with
other measurements and observations, for example, a systemic blood
pressure reading and infrared images of the tissue, to aid in
making the determination of the viability of the tissue.
[0073] The systemic blood pressure may be taken using any suitable
device, for example, a blood pressure cuff, applied to any suitable
body portion of the patient, for example, the arm of the patient.
With reference to FIG. 10, in step 402, an index may be calculated
by taking a ratio of the local perfusion pressure measured by the
tissue grasper 10 and the systemic blood pressure taken using the
blood pressure cuff. The index may be calculated by the computing
device and displayed as a number on the display 20 of the tissue
grasper 10. The calculated index is predictive of whether an
anastomotic leak may occur and/or the grade of an anastomotic leak.
As such, a surgeon can use the index to make a determination on
whether the two ends of the presumed healthy bowel segments are
healthy enough to be reconnected or whether more tissue needs to be
resected. For a detailed description of a method of calculating a
perfusion index, reference may be made to U.S. Pat. No. 7,618,376,
the entire contents of which were incorporated by reference
above.
[0074] To provide a more precise assessment of tissue viability,
the thermographic endoscope 2 may be used in conjunction with the
measurements taken by the tissue grasper 10 and the blood pressure
cuff. In step 404, infrared images of the subject tissue are
generated using thermographic endoscope 2 and in step 406, the
infrared images of the subject tissue are analyzed to observe the
heat distribution characteristics of the subject tissue. In some
embodiments, prior to step 404, tissue grasper 10 may be used to
initiate the grasp-then-release steps 302, 304, 306 of FIG. 4. In
step 408, the tissue may be assigned a numerical value by the
clinician based on the heat distribution characteristics observed
using the infrared images of the subject tissue displayed on
display 6. In step 410, this numerical value may be compared with
the local perfusion pressure/systemic blood pressure index to
provide a second index. In step 412, this second index may be
compared to a known index corresponding to viable tissue to
determine whether the tissue is viable. If the calculated second
index is the same or substantially the same as the known index
corresponding to viable tissue, the clinician continues to step
414, which includes reconnecting the two ends of the bowel
segments, thereby completing the anastomosis. Alternatively, if the
calculated second index deviates a threshold amount from the known
index corresponding to viable tissue, the clinician continues to
step 416, which includes resecting more of the tissue. This process
will have to be repeated until all of the tissue is determined to
be viable.
[0075] In some embodiments, the tissue grasper 10 may be
pre-programmed to clamp tissue at a predetermined clamping pressure
that is known to result in perfusion through the grasped tissue to
stop. The tissue grasper 10 may also be pre-programmed to reduce
the clamping pressure at a predetermined rate and automatically
send the pressure reading to the computing device at the moment
when perfusion through the grasped tissue restarts. The perfusion
pressure reading may also be displayed on the display 20. This
automated process eliminates human error in operating the tissue
grasper 10 by controlling the amount of clamping pressure being
applied to the tissue instead of the surgeon.
[0076] The tissue grasper 10 may also be used to determine the size
of the staples to be used in stapling the bowel segments together.
The staple size may be determined by viewing the third display
section 20c of the tissue grasper 10, which indicates the thickness
of the grasped tissue. The leg height of the staples selected for
the stapling procedure will correspond to the thickness of the
tissue. It is contemplated that the tissue thickness measured by
the third sensors 42c, 44c may be sent to the computing device,
which has stored therein a look-up table that contains a staple
size corresponding to each tissue thickness measurement.
[0077] In addition to the thermographic endoscope 2 and the tissue
grasper 10 being used to ensure that the tissue is in condition for
reconnecting (e.g., stapling) or acceptable for reconnecting, the
thermographic endoscope 2 and the tissue grasper 10 may also be
used as a check after the staples have been fired to ensure that
the tissue is healthy (e.g., has good blood flow, is healing
properly, etc.).
[0078] The thermographic endoscope 2 and the tissue grasper 10 may
also be configured to be incorporated into a robotic surgical
system (not shown). The robotic surgical system is powered locally
or remotely, and has electronic control systems localized in a
console or distributed within or throughout the robotic surgical
system. The robotic surgical system permits a surgeon to remotely
manipulate the thermographic endoscope 2 and the tissue grasper 10
to more precisely control the movement thereof. The surgical system
1 may be configured to send the infrared images generated by
thermographic endoscope 2 and the measurements gathered by the
sensors 42a-c, 44a-c of tissue grasper 10 to an interface of the
robotic surgical system on which the images and measurements may be
displayed for the surgeon to read.
[0079] Although the illustrative embodiments of the present
disclosure have been described herein, it is understood that the
disclosure is not limited to those precise embodiments, and that
various other changes and modifications may be affected therein by
one skilled in the art without departing from the scope or spirit
of the disclosure. All such changes and modifications are intended
to be included within the scope of the disclosure.
* * * * *