U.S. patent application number 16/552963 was filed with the patent office on 2022-08-18 for endoscopic vessel harvesting system components.
This patent application is currently assigned to MAQUET CARDIOVASCULAR LLC. The applicant listed for this patent is MAQUET CARDIOVASCULAR LLC. Invention is credited to Ryan C. ABBOTT, Kimberly D. BARKMAN, Peter L. CALLAS, Albert K. CHIN, Kenny L. DANG, Joseph N. LAMBERTI, Liming LAU, Arthur M. LIN, Ravinder D. PAMNANI, Michael C. STEWART, Geoffrey H. WILLIS.
Application Number | 20220257223 16/552963 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-18 |
United States Patent
Application |
20220257223 |
Kind Code |
A9 |
LAU; Liming ; et
al. |
August 18, 2022 |
ENDOSCOPIC VESSEL HARVESTING SYSTEM COMPONENTS
Abstract
Components for an endoscopic vessel harvesting system suitable
for harvesting target vessels such as the saphenous vein or radial
artery for cardiac artery bypass graft surgery. The main components
of such systems include a vessel dissector and a vessel harvester,
both of which work in conjunction with a separately provided
endoscope. The vessel dissector is an elongated cannula having a
blunt tip for separating layers of facial around vessels. The tip
may be movable, and is typically transparent to permit viewing
forward of the tip using the endoscope. Internal features of the
tip may reduce glare back to the endoscope. Several devices improve
visibility through the tip by reducing interference from tissue or
fluid on the tip. The vessel harvester also has an elongated
cannula for receiving the endoscope. Several tools within the
harvester permit manipulation, severing, and sealing of vessels
forward of the distal end. The tool for manipulating vessels may
have a low-profile for increased visibility of operation, and may
be coupled to the cannula with a damping mechanism to reduce the
possibility of avulsion of the vessels. Various vessel cutting and
sealing devices are provided that may accommodate various sizes of
vessels and improve cutting and sealing efficacy.
Inventors: |
LAU; Liming; (Mountain View,
CA) ; CALLAS; Peter L.; (Castro Valley, CA) ;
STEWART; Michael C.; (San Jose, CA) ; WILLIS;
Geoffrey H.; (Los Altos, CA) ; ABBOTT; Ryan C.;
(San Jose, CA) ; BARKMAN; Kimberly D.; (Redwood
City, CA) ; CHIN; Albert K.; (Palo Alto, CA) ;
DANG; Kenny L.; (Laguna Niguel, CA) ; LAMBERTI;
Joseph N.; (Castro Valley, CA) ; LIN; Arthur M.;
(Fremont, CA) ; PAMNANI; Ravinder D.; (Los Altos,
CA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
MAQUET CARDIOVASCULAR LLC |
Wayne |
NJ |
US |
|
|
Assignee: |
MAQUET CARDIOVASCULAR LLC
Wayne
NJ
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20190380688 A1 |
December 19, 2019 |
|
|
Appl. No.: |
16/552963 |
Filed: |
August 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15686703 |
Aug 25, 2017 |
11141055 |
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16552963 |
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11446024 |
Jun 1, 2006 |
9770230 |
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15686703 |
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International
Class: |
A61B 17/00 20060101
A61B017/00 |
Claims
1-16. (canceled)
17. A vessel dissector that is used in conjunction with an
endoscope, comprising: an elongated cannula including a lumen
therein for receiving the endoscope; and a transparent blunt tip
provided on a distal end of the elongated cannula that permits an
operator of the dissector to dissect tissue while viewing internal
body structures via an objective lens of the endoscope; and a wiper
for clearing tissue from the exterior of the transparent blunt
tip.
18. The vessel dissector of claim 17, wherein the wiper is arranged
on the elongated cannula to pivot about an axis to alternately
contact and disengage from the transparent blunt tip, and a
mechanism for rotating the blunt tip.
19. The vessel dissector of claim 17, wherein the wiper is arranged
on the elongated cannula to contact the blunt tip and swivel about
the axis of the device.
20. The vessel dissector of claim 17, wherein the wiper is an
O-ring wiper fitted over the blunt tip and connected to an
actuation rod that displaces the O-ring wiper longitudinally to
wipe over the blunt tip.
21. The vessel dissector of claim 17, wherein the wiper is arranged
on the elongated cannula to contact the blunt tip and has an
energized cutting electrode thereon to remove tissue via
ablation.
22. The vessel dissector of claim 17, further including a handle
disposed at a proximal end of the elongated cannula and a thumb
lever thereon connected to an actuating rod for displacing the
wiper relative to the transparent blunt tip and clearing tissue
therefrom.
23-62. (canceled)
63. A tissue dissector, comprising: an elongated cannula including
a distal end and a lumen for receiving an endoscope; a tissue
dissection tip configured for dissecting tissue, wherein the tissue
dissection tip comprises a conical one piece structure tapering to
a blunt end configured for tissue dissection, and is coupled to the
distal end of the elongated cannula; an articulation interface
between the elongated cannula and the tissue dissection tip, the
articulation interface comprising an articulation body; and a first
control member comprising a first elongated body extending through
the elongated cannula and connected to the tissue dissection tip,
wherein the first control member engages and applies a force to the
tissue dissection tip and is configured to tilt the tissue
dissection tip relative to a longitudinal axis of the elongated
cannula so as to directionally orient and facilitate
maneuverability of the tissue dissection tip; wherein the
articulation body is configured to change an angle of the tissue
dissection tip relative to the longitudinal axis of the elongated
cannula and wherein the articulation interface exerts a force
sufficient to revert the tissue dissection tip back to axial
alignment with the longitudinal axis of the elongated cannula when
the force applied by the first control member is released; and
wherein the first control member occupies a space in the elongated
cannula, and the tissue dissection tip is transparent.
64. The tissue dissector of claim 63, further comprising a second
control member comprising an elongated body extending through the
elongated cannula and connected to the tissue dissection tip,
wherein the second control member applies a force to the tissue
dissection tip for tilting the transparent structure relative to
the elongated cannula.
65. The tissue dissector of claim 63, wherein the articulation
interface comprises an accordion-like flexible sleeve that is
coupled between the tissue dissection tip and the elongated
cannula.
66. The tissue dissector of claim 63, wherein the articulation
interface comprises a spherical bearing surface coupled between the
tissue dissection tip and the elongated cannula.
67. The tissue dissector of claim 63, further comprising an opening
disposed to deliver insufflation gas, wherein the opening is
located at the tissue dissection tip.
68. The tissue dissector of claim 67, further comprising a barrier
covering the opening.
69. The tissue dissector of claim 63, further comprising an opening
for delivering gas, wherein the opening is located at a side of the
elongated cannula.
70. The tissue dissector of claim 69, further comprising a barrier
covering the opening.
71. The tissue dissector of claim 63, wherein the first control
member is configured to tilt the tissue dissection tip about an
axis that is perpendicular to the longitudinal axis of the
elongated cannula.
72. The tissue dissector of claim 63, wherein the endoscope and the
first control member occupy different respective space in the
elongated cannula.
73. The tissue dissector of claim 63, wherein the first control
member is spaced apart from the endoscope and comprises a steering
wire.
74. The tissue dissector of claim 63, wherein the tissue dissection
tip has an inner surface that is aligned with a center of the
lumen, the inner surface oriented to prevent light from being
reflected towards the center of the lumen.
75. The tissue dissector of claim 63, wherein the first control
member extends through the tissue dissection tip and is connected
to a surface of the tissue dissection tip under tension and wherein
the first control member applies a pull force with respect to the
tissue dissection tip for tilting the tissue dissection tip
relative to the longitudinal axis of the elongated cannula.
76. A tissue dissector, comprising: an elongated cannula including
a distal end and a lumen for receiving an endoscope; a tissue
dissection tip configured for dissecting tissue, wherein the tissue
dissection tip comprises a conical one piece structure tapering to
a blunt end configured for tissue dissection, and is coupled to the
distal end of the elongated cannula; an articulation interface
between the elongated cannula and the tissue dissection tip, the
articulation interface comprising an articulation body; a first
control member comprising a first elongated body extending through
the elongated cannula and connected to the tissue dissection tip,
wherein the first control member applies a force to the tissue
dissection tip and is configured to tilt the tissue dissection tip
relative to a longitudinal axis of the elongated cannula so as to
directionally orient and facilitate maneuverability of the tissue
dissection tip; and a second control member comprising an elongated
body extending through the elongated cannula and connected to the
tissue dissection tip, wherein the second control member applies a
force to the tissue dissection tip and is configured to tilt the
tissue dissection tip relative to the longitudinal axis of the
elongated cannula so as to directionally orient and facilitate
maneuverability of the tissue dissection tip; wherein the
articulation body is configured to change an angle of the tissue
dissection tip relative to the longitudinal axis of the elongated
cannula; and wherein the first control member and the second
control member each occupies a space in the elongated cannula.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to surgical devices and
methods for dissection and removal of blood vessels from a
patient's body and, in particular, to endoscopic vessel harvesting
systems, components and methods.
BACKGROUND OF THE INVENTION
[0002] Endoscopic harvesting of vessels is well known in the
surgical field and has been the subject of a great deal of recent
technological advancement. Typically, the harvested vessel is used
for bypass or as a shunt around an artery that has diminished flow
from stenosis or other anomaly, such as in a Coronary Artery Bypass
Grafting (CABG) procedure. Often in CABG, a saphenous vein from the
patient's leg is harvested for subsequent use in the surgery. Other
vessels, such as the radial artery, can also be harvested and used
in this manner. Vessel harvesting involves liberating the vessel
from surrounding tissue and transecting smaller side branches,
cauterizing, tying or ligating the vessel at a proximal site and a
distal site, and then transecting the vessel at both sites before
it is removed from the body.
[0003] Known endoscopic methods and devices for performing vessel
harvesting are discussed in detail in U.S. Pat. No. 6,176,825 to
Chin, et al., Re 36,043 to Knighton, U.S. Pat. No. 6,406,425 to
Chin, et al., and U.S. Pat. No. 6,471,638 to Chang, et al., all of
which are expressly incorporated herein by reference. Furthermore,
various devices and methods disclosed in U.S. Pat. No. 5,895,353 to
Lunsford, et al., and U.S. Pat. No. 6,162,173 to Chin, et al., and
pending patent application Ser. No. 10/602,490 entitled "Apparatus
and Method for Integrated Vessel Ligator and Transector" are also
expressly incorporated herein by reference. Also, commercial vessel
harvesting systems sold under the tradename VASOVIEW.RTM. Uniport
Plus, VASOVIEW.RTM. 5, VASOVIEW.RTM. 6, and VASOVIEW.RTM. 7 are
available from Guidant Corporation of Santa Clara, Calif.
[0004] Another version of an endoscopic vessel harvesting system is
disclosed in U.S. Patent Publication No. 2003/0130674 to Kasahara,
et al., filed on Dec. 24, 2002, or and later updated in U.S. Patent
Publication No. 2005/0159764 also to Kasahara, et al., filed Oct.
27, 2004. In these systems, various devices are utilized to first
dissect a vein from surrounding tissue and then harvest the vein.
Each of the devices passes through a guide tube of a trocar
inserted through a body surface, such as disclosed in U.S. Pat. No.
6,863,674 also to Kasahara, et al., filed Dec. 23, 2002. Certain
elements of these and other related patent disclosures are evident
in the VirtuoSaph.TM. endoscopic vein harvesting system (see,
www.terumo-cvs.com/products) marketed by Terumo Cardiovascular
Systems Corp. of Japan.
[0005] Despite accepted endoscopic vessel harvesting systems and
techniques, there remains a need for systems and components that
both make the user's task less complicated and improve the surgical
outcome.
SUMMARY OF THE INVENTION
[0006] The present invention provides an endoscopic vessel
harvesting system suitable for harvesting various target vessels
that allows for simple and convenient operation in a limited space.
The invention includes improvements to various components of vessel
harvesting systems each of which can be used with any of the other
component improvements. It should be understood, therefore, that
even if a particular combination is not explicitly described, any
one component can be used with any other component disclosed herein
unless that combination is structurally impossible.
[0007] In accordance with a first embodiment, the present invention
provides a vessel dissector that is used in conjunction with an
endoscope, comprising an elongated cannula including a lumen
therein for receiving the endoscope, the elongated cannula further
housing a passage for delivery of an insufflation gas therethrough.
The vessel dissector has an input for connecting to a supply of
insufflation gas, the input being in fluid communication with the
passage. A port opens near the distal end of the elongated cannula
in fluid communication with the passage and out of which
insufflation gas is expelled. A fluid barrier covers the port that
permits expulsion of insufflation gas from the passage within the
elongated cannula and prevents ingress of fluid from outside the
elongated cannula through the port to the passage.
[0008] The port may be formed in the side of the elongated cannula.
Desirably, the fluid barrier comprises a tubular member surrounding
the distal end of the elongated cannula and covering the port. In
one embodiment, the fluid barrier comprises a polymer shield that
closes off the port from the outside but is flexible so that
insufflation gas may escape from the passage therethrough. In
another embodiment, the fluid barrier comprises a gas-permeable
liquid-resistant membrane that permits escape of insufflation gas
therethrough but prevents entrance of fluid to the passage.
[0009] The vessel dissector may further include a transparent
conical tip on a distal end of the elongated cannula that permits
an operator of the dissector to dissect tissue while viewing
internal body structures via an objective lens of the endoscope
positioned close to the blunt tip. The insufflation gas port may be
located at the apex of the conical tip. The vessel dissector may
also have a coupling between the distal end of the elongated
cannula and the transparent blunt tip and a control member
extending through the elongated cannula to enable the user to angle
the tip relative to the axis of the elongated cannula. For
instance, the coupling may be an accordion-like flexible interface
or sleeve, or a spherical bearing surface.
[0010] In accordance with a second embodiment, the present
invention provides a vessel dissector that is used in conjunction
with an endoscope, comprising an elongated cannula including a
lumen therein for receiving the endoscope. A hollow outwardly
conical transparent dissecting tip on a distal end of the elongated
cannula permits an operator of the dissector to dissect tissue
while viewing internal body structures via an objective lens of the
endoscope. The tip comprises a structure generally arranged about
an axis and having an inner wall that terminates at a distal end in
a shape that tends to reduce glare back to the objective lens of
the endoscope in comparison to a conical inner wall that tapers
symmetrically to an apex. For example, the shape of the distal end
of the inner wall of the dissecting tip may be an inner tapering
surface that terminates at its distal end in a line so as to form
an elongated inner corner, an inner surface that tapers downward
toward its distal end and terminates in a flat surface set at an
angle from the axis of the tip, or a backward wedge. Desirably, the
dissecting tip has a tip diameter and the elongated cannula has a
diameter adjacent the dissecting tip that is between about 50-75%
of the tip diameter.
[0011] In a more robust system, the vessel dissector may also
include a vessel holding tool extending through the elongated
cannula and adapted for longitudinal movement therein, and a vessel
severing tool such as a tissue welder extending through the
elongated cannula and adapted for longitudinal movement therein. In
this embodiment, the dissecting tip includes apertures for passage
of the vessel holding tool and the vessel severing tool.
Preferably, both the vessel holding tool and the vessel severing
tool dock into recesses in the dissecting tip and have exterior
shapes that conform to the conical exterior of the dissecting tip
so as to match its shape.
[0012] In accordance with a third embodiment, the present invention
provides a vessel dissector that is used in conjunction with an
endoscope. The vessel dissector is defined by an elongated cannula
including a lumen therein for receiving the endoscope. A
transparent blunt tip on a distal end of the elongated cannula
permits an operator of the dissector to dissect tissue while
viewing internal body structures via an objective lens of the
endoscope. A wiper clears tissue from the exterior of the
transparent blunt tip. The wiper may be arranged on the elongated
cannula to pivot about an axis to alternately contact and disengage
from the transparent blunt tip, and a mechanism for rotating the
blunt tip. Alternatively, the wiper is arranged on the elongated
cannula to contact the blunt tip and swivel about the axis of the
device. Still further, the wiper may be an O-ring wiper fitted over
the blunt tip and connected to an actuation rod that displaces the
O-ring wiper longitudinally to wipe over the blunt tip. In one
embodiment, the wiper is arranged on the elongated cannula to
contact the blunt tip and has an energized cutting electrode
thereon to remove tissue via ablation. Preferably, a handle
disposed at a proximal end of the elongated cannula has a thumb
lever thereon connected to an actuating rod for displacing the
wiper relative to the transparent blunt tip and clearing tissue
therefrom.
[0013] In accordance with a fourth embodiment, a vessel harvester
used in conjunction with an endoscope comprises an elongated
cannula including a lumen therein for receiving the endoscope, and
a vessel holding tool extending through the elongated cannula and
adapted for longitudinal movement therein. A distal end of the
vessel holding tool includes a vessel hook and a locking member
used to capture a target vessel, wherein the hook is open on one
side and extension of the locking member closes the open side so
that the target vessel is completely surrounded and captured
therein. A vessel severing tool extends through the elongated
cannula for longitudinal movement therein, and has a distal
operative end with structure for severing a target vessel. The
vessel holding tool includes a support rod that extends through the
elongated cannula and which is configured to angle laterally at a
location close to the distal end of the tool to enable lateral
vessel manipulation and improve positioning of the vessel severing
tool relative to the target vessel.
[0014] Desirably, the support rod is bent out of a plane in which
the support rod lies at a location close to the distal end of the
vessel holding tool such that the distal end angles either toward
or away from the vessel severing tool. The support rod may be
flexible such that the bend is retracted into the cannula and
distal extension of the vessel holding tool from the end of the
elongated cannula displaces its distal end laterally. A flexible
support rod may be surrounded by a rigid hypotube also adapted for
longitudinal movement with respect to the cannula, wherein
extension of both the support rod and hypotube from the cannula and
then retraction of the hypotube from around the support rod angles
the vessel holding tool. Alternatively, the support rod is bent out
of a plane in which the support rod lies at a location close to the
distal end of the vessel holding tool using an active angling
mechanism controlled from a proximal end of the elongated
cannula.
[0015] The vessel hook of the vessel holding tool may include a
blunt tapered distal dissecting surface for blunt dissection of
tissue. Further, the vessel hook of the vessel holding tool defines
a space therein for receiving a target vessel, and the locking
member may be shaped as a large wedge to reduce the space within
the open vessel hook by about 50% and includes a tapered leading
edge that helps prevent pinching of the target vessel as the
locking member extends.
[0016] In accordance with a fifth embodiment, the present invention
provides a vessel harvester that is used in conjunction with an
endoscope, comprising an elongated cannula including a lumen
therein for receiving the endoscope. A vessel severing tool extends
through the elongated cannula for longitudinal movement therein,
the severing tool having a distal operative end with structure for
severing a target vessel. A vessel holding tool also extends
through the elongated cannula for longitudinal movement therein and
has a single support rod that extends through the elongated cannula
and a distal end with a vessel hook and a locking member used to
capture a target vessel and manipulate it to present a side branch
of the target vessel to the vessel severing tool. The hook is open
on one side and extension of the locking member closes the open
side so that the target vessel is completely surrounded and
captured therein. The locking member extends concentrically from
the single support rod on one lateral side of the vessel hook, the
single support rod therefore reducing endoscopic viewing
impediments relative to more than one support rod.
[0017] The support rod may be configured to angle laterally at a
location close to the distal end of the tool to enable lateral
vessel manipulation and improved positioning of the vessel severing
tool relative to the target vessel. Desirably, the vessel hook of
the vessel holding tool includes a blunt tapered distal dissecting
surface for blunt dissection of tissue.
[0018] In accordance with a sixth embodiment, the present invention
provides a vessel harvester that is used in conjunction with an
endoscope, comprising an elongated cannula including a lumen
therein for receiving the endoscope. A vessel severing tool extends
through the elongated cannula for longitudinal movement therein,
the severing tool having a distal operative end with structure for
severing a target vessel. A vessel holding tool also extends
through the elongated cannula for longitudinal movement therein.
The vessel holding tool has a support rod that extends through the
elongated cannula and a distal end with a vessel hook and a locking
member used to capture a target vessel and manipulate it to present
a side branch of the target vessel to the vessel severing tool. The
hook is open on one side and extension of the locking member closes
the open side so that the target vessel is completely surrounded
and captured therein. The distal end of the vessel holding tool
including the hook and locking member are constructed of a thin
wireform for reduced impediment to endoscopic viewing. Preferably,
the thin wireform is formed of metal or plastic wires having a
thickness of between about 0.5 mm and 1.0 mm. Desirably, the
support rod is configured to angle laterally at a location close to
the distal end of the tool to enable lateral vessel manipulation
and improved positioning of the vessel severing tool relative to
the target vessel.
[0019] In accordance with a seventh embodiment, the present
invention provides a vessel harvester that is used in conjunction
with an endoscope, comprising an elongated cannula including a
lumen therein for receiving the endoscope. A vessel severing tool
extends through the elongated cannula for longitudinal movement
therein, the severing tool having a distal operative end with
structure for severing a target vessel. A vessel holding tool also
extends through the elongated cannula for longitudinal movement
therein. The vessel holding tool has a support rod that extends
through the elongated cannula and a distal end with a vessel holder
used to capture a target vessel and manipulate it to present a side
branch of the target vessel to the vessel severing tool. A damped
slip mechanism provided around the support rod of the vessel
holding tool permits relative movement between the cannula and the
support rod if the vessel holder catches on any body structure and
generates a reaction force in the support rod in opposition to
movement of the cannula. For instance, the damped slip mechanism
comprises a friction collar surrounding the support rod, or a
piston/cylinder/spring arrangement that couples movement of the
support rod and cannula.
[0020] In a preferred embodiment wherein the vessel holder of the
vessel holding tool is open on one side and defines a space therein
for receiving a target vessel. A locking member moves to close the
open side of the holder so that the target vessel is completely
surrounded and captured therein. The locking member is shaped as a
large wedge to reduce the space within the open vessel holder by
about 50% and includes a tapered leading edge that helps prevent
pinching of the target vessel as the locking member moves. Also,
the vessel holding tool has improved visibility by virtue of a
single support rod that extends through the elongated cannula,
wherein the locking member extends concentrically from the single
support rod on one lateral side of the vessel holder, the single
support rod therefore reducing endoscopic viewing impediments
relative to more than one support rod. Desirably, the distal end of
the vessel holding tool including the holder and locking member are
constructed of a thin wireform for reduced impediment to endoscopic
viewing.
[0021] In accordance with an eighth embodiment, the present
invention provides a vessel harvester that is used in conjunction
with an endoscope, comprising an elongated cannula including a
lumen therein for receiving the endoscope. A vessel severing tool
extends through the elongated cannula for longitudinal movement
therein, the severing tool has a distal operative end with an open
mouth for receiving a target vessel that automatically accommodates
widely varying sizes of vessel, and a severing device associated
with the mouth. A vessel holding tool extends through the elongated
cannula for longitudinal movement therein, the vessel holding tool
having structure used to capture a target vessel and manipulate it
to relative to the vessel severing tool. The mouth of the vessel
severing tool preferably accommodates vessels having diameters that
range from between 0.5 and 1.0 mm.
[0022] In one embodiment, the mouth has facing vessel contacts that
flex apart upon receiving a vessel therebetween. The severing
device may have bipolar electrodes disposed to contact a target
vessel received within the mouth. For instance, the bipolar
electrodes comprise wire electrodes arranged in a crossing pattern
in the mouth. In another version, the mouth has a stepped shape
with several progressively smaller intermediate gaps having
generally parallel sides that provide regions of constant width
surface contact with the vessel. The intermediate gaps may have
widths in decreasing increments of 1.0 mm. The severing device may
be a mechanical cutter disposed transverse to a target vessel
received within the mouth. For efficacy, a fluid conduit terminates
close to the distal operative end of the vessel severing tool and
is adapted to deliver a fluid jet to knock away tissue that may
stick to the distal operative end.
[0023] The vessel severing tool may be connected to a control rod
and located within an arcuate slot formed in the elongated cannula,
the control rod being capable of translating the distal operative
end laterally within the arcuate slot as well as longitudinally.
The mouth of the vessel severing tool may open to one side of the
distal operative end. The vessel holding tool may includes a
support rod that extends through the elongated cannula and is bent
out of a plane in which the support rod lies at a location close to
the distal end of the vessel holding tool such that the distal end
angles either toward or away from the vessel severing tool.
[0024] In accordance with a ninth embodiment, the present invention
provides a vessel harvester that is used in conjunction with an
endoscope, comprising an elongated cannula including a lumen
therein for receiving the endoscope. A pair of partial tubular
vessel shields extend from the cannula and define a lumen sized to
receive a target vessel, the partial tubular vessel shields
defining gaps therebetween sized to receive a side branch extending
from the target vessel. A tubular cutting element sized to surround
the partial tubular vessel shields and axially displaceable from
the cannula, advances to sever any side branch received within the
gaps while the partial tubular vessel shields protect the target
vessel from the severing operation. The vessel severing tool may be
a tubular knife blade. A fluid conduit terminating close to the
partial tubular vessel shields may be adapted to deliver a fluid
jet to knock away tissue that may stick to the vessel shields.
[0025] In accordance with a tenth embodiment, the present invention
provides a vessel harvester that is used in conjunction with an
endoscope, comprising an elongated cannula including a lumen
therein for receiving the endoscope. A pair of fork-shaped vessel
sealing electrodes having tines are spaced laterally apart so as to
create a gap therebetween. A vessel capturing mandible moves within
the gap between the electrodes to capture a target vessel
positioned between the tines. A severing blade moves within the gap
and sever the target vessel. Desirably, the vessel capturing
mandible has a serrated distal finger to securely capture the
target vessel within the tines. Both of the vessel capturing
mandible and severing blade may have control rods and angled
proximal surfaces that cam against a distal end of the elongated
cannula and displace them toward one another upon proximal
retraction of the control rods. A fluid conduit terminating close
to the fork-shaped vessel sealing electrodes may deliver a fluid
jet to knock away tissue that sticks to the sealing electrodes.
[0026] A further understanding of the nature and advantages of the
present invention are set forth in the following description and
claims, particularly when considered in conjunction with the
accompanying drawings in which like parts bear like reference
numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Features and advantages of the present invention will become
appreciated as the same become better understood with reference to
the specification, claims, and appended drawings wherein:
[0028] FIG. 1A is a perspective view of an endoscopic vessel
dissector of the prior art;
[0029] FIG. 1B is a perspective view of an endoscopic vessel
harvester of the prior art;
[0030] FIG. 1C is a perspective view of an access trocar of the
prior art;
[0031] FIGS. 2A and 2B are side views of the distal end of
alternative vessel dissectors of the present invention including
articulated dissecting tips;
[0032] FIG. 3 is a side view schematically illustrating the
possible path of bodily fluids into the prior art endoscopic vessel
dissector of FIG. 1A;
[0033] FIGS. 4A and 4B are side views of the distal end of
alternative vessel dissectors of the present invention including
structures for inhibiting ingress of bodily fluids into the
dissector cannula;
[0034] FIG. 5A is a schematic side view of an endoscopic vessel
dissector of the prior art passing through body tissue;
[0035] FIG. 5B is a schematic side view of an endoscopic vessel
dissector of the present invention having a narrowed cannula for
easier passage through body tissue;
[0036] FIGS. 6A-6C are longitudinal sectional views through
alternative transparent conical tips for use with endoscopic vessel
dissectors of the present invention;
[0037] FIG. 7 is a schematic sectional view of the distal end of an
alternative endoscopic vessel dissector of the present invention
which incorporates tools for harvesting vessels;
[0038] FIG. 8 is a perspective view of an endoscopic vessel
dissector of the present invention having a wiper blade for
clearing the distal tip;
[0039] FIGS. 9 and 10 are perspective views of the distal tip of
two alternative endoscopic vessel dissectors of the present
invention both having tip wiping capabilities;
[0040] FIGS. 11A and 11B are schematic side views of an endoscopic
vessel harvester of the prior art showing vessel holding and
severing tools extended from the distal end of a cannula;
[0041] FIGS. 12A and 12B are schematic side views of an endoscopic
vessel harvester of the present invention showing vessel holding
and severing tools extended from the distal end of a cannula
wherein the vessel holding tool translates laterally for better
vessel retraction;
[0042] FIG. 13 is a schematic side view of an alternative
endoscopic vessel harvester of the present invention wherein a
vessel holding tool includes a tip angled toward the vessel
severing tool;
[0043] FIGS. 14A-14C are several views of the transverse
displacement of an alternative vessel holding tool from an
endoscopic vessel harvester of the present invention;
[0044] FIGS. 15A-15B are side and perspective views of an
alternative vessel holding tool of the present invention having one
connecting rod;
[0045] FIGS. 16A-16B are side and perspective views of a low
profile vessel holding tool of the present invention formed of thin
wire;
[0046] FIGS. 17A-17B are partial sectional views of alternative
vessel holding tools of the present invention incorporating a
mechanism for preventing vessel avulsion;
[0047] FIG. 18 is a side view of the distal end of an alternative
vessel holding tool of the present invention having an enlarged
locking member for better positioning of the vessel;
[0048] FIGS. 19A and 19B are schematic views of an alternative
vessel severing tool of the present invention having wire
electrodes extending into an enlarged vessel-receiving gap;
[0049] FIG. 20 is a schematic view of an alternative vessel
severing tool of the present invention having a stepped vessel
receiving gap;
[0050] FIGS. 21A-21B are two side views of a vessel severing tool
of the present invention having movable jaws;
[0051] FIG. 22 is a side view of a vessel severing tool of the
present invention having rotary blades incorporated therein;
[0052] FIGS. 23A-23B are two side views of a vessel severing tool
of the present invention having a movable blade;
[0053] FIG. 24 is a schematic view of a vessel severing tool of the
present invention having a system for clearing tissue therefrom
using gas jets;
[0054] FIGS. 25A-25B are front and top section views, respectively,
of an alternative vessel severing tool of the present invention
capable of translating transversely as well as longitudinally;
[0055] FIG. 26 is a schematic front view of an alternative vessel
severing tool of the present invention having a tubular cutting
element surrounding a tubular primary vessel shield;
[0056] FIGS. 27A-27B are side elevational and top plan views,
respectively, of a further alternative vessel severing/sealing tool
that incorporates a movable mandible for capturing a vessel and a
mechanical blade for severing it;
[0057] FIGS. 28A-28B are two schematic views of a side-opening
vessel severing/sealing tool;
[0058] FIG. 29 is a longitudinal endoscopic view showing the use of
the tool in FIGS. 28A-28B; and
[0059] FIG. 30 is a top plan view of an alternative severing tool
having a ring and concentric coil bipolar electrode structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] The present application provides a number of improvements to
prior art vessel harvesting systems. The disclosures herein of
various component parts of vessel harvesting systems should be
viewed with the presumption that each can work in combination with
other components unless stated as being mutually exclusive. For
example, the various endoscopic vessel dissectors described herein
may be utilized in combination with any of the endoscopic vessel
harvesters. Moreover, any single one component improvement
described herein may be incorporated into any existing vessel
harvesting system, again, unless the structures or functions are
mutually exclusive.
Prior Endoscopic Vessel Harvesting System
[0061] The three primary components of an exemplary prior art
vessel harvesting system are seen in the separate views of FIGS.
1A-1C. This particular system is representative of one type of
prior art vessel harvesting systems, and many of the improvements
described herein will be described with direct reference to it.
However, as will be understood by one of skill in the art, any one
single improvement to a subcomponent of the vessel harvesting
system may, in most cases, be incorporated into other such systems.
More important, if any single improvement(s) are independently
claimed, the application should not be construed as being limited
to the system shown in FIGS. 1A-1C. That said, the exemplary prior
art system includes an endoscopic dissector 20 in FIG. 1A, an
endoscopic vessel harvester 22 seen in FIG. 1B, and an access
trocar 24 seen in FIG. 1C.
[0062] The endoscopic dissector 20 includes an elongated tube or
cannula 30 extending between a distal conical tip 32 and a proximal
handle 34. A bell-shaped port 36 on a proximal end of the handle 34
receives a conventional medical endoscope 38 which may be fitted
with an optical connector 40. Although not shown, the elongated
shaft of the endoscope 38 extends through the entire length of the
dissector 20 such that a viewing end terminates in proximity to the
conical tip 32, which is typically transparent. It should be
understood that vessel harvesting systems are typically disposable
and are packaged and sold separately from the endoscope which is
typically reused. In all cases, however, these endoscopic vessel
harvesting systems are designed to accommodate and function with a
conventional endoscope, and are therefore claimed accordingly.
[0063] Tubing 42 supplies insufflation gas into an input within the
handle 34 that opens into an elongated passage within the cannula
30 in communication with a distal egress port 44. In use, the user
inserts the distal tip 32 and cannula 30 into the body through an
access device such as the trocar 24 seen in FIG. 1C, and into
proximity with a target vessel, such as the saphenous vein in the
leg. By pushing the conical tip 32 along the target vessel under
endoscopic vision, the user is able to grossly dissect connecting
tissue from around the vessel. Insufflation gas forced out of the
distal port 44 pressurizes the dissected cavity and facilitates
viewing and further dissection. After a desired length of target
vessel has been separated from surrounding tissue, the dissector 20
is removed from the patient.
[0064] Subsequent to vessel dissection, the vessel harvester 22 is
inserted through the access trocar 24 and into the dissected cavity
around the target vessel. The vessel harvester 22 also includes an
elongated tube or cannula 50 extending between an open distal end
52 and a proximal handle 54. Again, a conventional endoscope 38
snaps into a proximal bell-shaped port 56 that includes an axial
slot 58 to receive the perpendicularly-extending optical connector
40. As with the dissector 20, the elongated shaft of the endoscope
passes entirely through the cannula 50 and terminates at a viewing
end or objective lens 60 close to the open distal end 52.
[0065] The harvester 22 further includes tools to sever side
branches from the target vessel while simultaneously closing them
off to prevent bleeding. For instance, a holding tool 62 may be
used to manipulate the target vessel so that a severing and sealing
tool 64 has clear access to the various side branches. Each of
these tools may be manipulated by controls 66 provided in the
handle 54. One of the controls 66 is a thumb lever thumb lever that
connects to a wiper blade at the distal end of the elongated
cannula 50 for clearing the objective lens 60 of the endoscope. To
facilitate the harvesting operation, an insufflation system
including tubing 68 may be provided so that gas may be passed out
the open distal end 52 of the cannula 50. Also, electrical wires 70
connect to the handle 54 to provide energy for a coagulator
incorporated into the severing and sealing tool 64. It should be
understood that as generally described so far, these components of
the prior art vessel harvesting system are well known in the art,
the present application dealing with improvements thereto.
[0066] The third main component of the harvesting system is the
access trocar 24 seen in FIG. 1C. In this embodiment, the trocar
includes a main access tube 70 having an angled distal tip 72 and a
proximal housing 74. Although not shown, an inner seal such as a
diaphragm seal may be incorporated within the housing 74 to provide
a gas-tight interface with the dissector 20 or harvester 22 that
passes through the trocar 24. The main access tube 70 extends
through an incision in the body and a spring-biased clip 76 secures
the trocar thereto.
Improvements to Dissection Function
[0067] FIG. 2A shows the distal end of an alternative vessel
dissector 80 of the present invention including an articulated
dissecting tip 82. The tip 82 connects to an elongated cannula 84
via an accordion-like flexible interface or sleeve 86. A pair of
pull wires 88 extends through the cannula 84 and attaches to points
on opposite sides of the dissecting tip 82. By manipulating the
pull wires 88, the user can angle the generally conical tip 82 in
either direction within a plane, relative to the axis of the
elongated cannula. By rotating the entire cannula 84, a full
360.degree. range of tip movement is obtained. The flexible sleeve
86 acts like a compression spring and tends to revert the tip 82
back to an axial alignment when pull forces are released.
[0068] FIG. 2B is another alternative vessel dissector 90 having an
articulated dissecting tip 92. As with the dissector 80, the tip 92
connects to the distal end of an elongated cannula 94 in a manner
that enables it to be angled within a plane with respect to the
cannula. In this embodiment, a spherical bearing surface 96
provides the interface between the tip 92 and cannula 94. A pair of
pull wires 98 connected to the tip 92 enables the user to angle the
tip as desired. A flexible spine of sorts (not shown) may also be
provided to provide a force that restores the axial alignment of
the tip 92 when pull forces are released.
[0069] FIG. 3 is a side view schematically illustrating the
possible path of bodily fluids into an existing endoscopic vessel
dissector 100 that includes one or more ports 102 near its distal
end for insufflation of gas such as CO.sub.2. That is, a passage is
provided within the cannula of the vessel dissector 100 to deliver
gas from a proximal end thereof to the ports 112. If fluid is
permitted to enter the cannula through the insufflation ports 102,
it may eventually migrate to within the transparent distal tip and
interfere with endoscopic viewing therefrom.
[0070] FIG. 4A illustrates the distal end of an alternative vessel
dissector 110 of the present invention including a small fluid
barrier 112 extending proximally from the distal tip 114 for
inhibiting ingress of bodily fluids into insufflation ports 116
formed in the side of the dissector cannula. The fluid barrier 112
in this embodiment comprises a tubular shield which can be formed
from relatively thin medical plastics. The fluid barrier 112 is
desirably flexible enough to permit gas egress from the ports 116
while preventing liquid or solid ingress, much like a reed
valve.
[0071] FIG. 4B shows an alternative vessel dissector 120 having an
alternative fluid barrier 122 surrounding the distal end thereof
near the distal tip 124. The fluid barrier 122 in this embodiment
comprises a tubular porous membrane that covers the gas
insufflation ports 126 in the side of the dissector cannula so that
liquid or solid is prevented from entering though gas can exit. The
membrane 122 is any medically suitable gas-permeable
liquid-resistant barrier such as ePTFE made by W.L. Gore.
[0072] In a further embodiment, the port from which insufflation
gas is expelled is located not on the cannula body, but on a
dissecting tip secured to the distal end thereof. For example, the
dissecting tips 82, 92 of FIGS. 2A/2B may feature a port from which
gas escapes into the surrounding tissue cavity. Alternatively, a
transparent conical tip 32 as in FIG. 1A may have a port formed at
the distal apex. In each of these alternatives, a fluid barrier
desirably fills or covers the port to prevent liquid or solid
ingress, while permitting gas egress. Forming the port on the
dissecting tip may be advantageous because the gas is expelled
farther distally, and a selection of different tips as desired may
be coupled to a generic cannula.
[0073] FIG. 5A is a schematic side view of an endoscopic vessel
dissector 100 of the prior art passing through body tissue 104.
Insufflation assists in maintaining the dissected cavity or tunnel,
though there may be friction between tissue and the following
cannula 106 because of its equal size relative to the dissecting
tip 108.
[0074] To help facilitate passage of the cannula through tissue, an
endoscopic vessel dissector 130 of the present invention seen in
FIG. 5B includes a narrowed cannula 132, at least adjacent to a
dissecting tip 134 and desirably along its entire length. The
cannula 132 has a diameter that is smaller than the diameter of the
dissecting tip 134, and preferably between about 50-75% of the
diameter of the dissecting tip 134. A narrow cannula proximal to
the dissecting tip improves maneuverability and reduces shaft
friction within the dissected tunnel.
[0075] FIGS. 6A-6C are longitudinal sectional views through
alternative transparent tips for use with endoscopic vessel
dissectors of the present invention. Prior transparent dissection
tips, such as seen in U.S. Pat. No. 5,980,549 to Chin, et al.,
include a hollow interior with a front wall tapering to a sharp
point, or apex. The outer profile retains a more rounded, blunt
configuration for atraumatic dissection. The sharp inner apex helps
remove a spot of distortion in the center of the visual field.
[0076] In addition to distortion, some conical blunt dissection
tips made of clear materials reflect light from the light fibers
back to the objective lens of the endoscope. To address this need,
a generally conical dissection tip 140 in FIG. 6A includes an inner
tapering surface 142 that terminates at its distal end in a line
144 so as to form an elongated inner corner, or reverse wedge
shape. This configuration works to reduce glare back to the
objective lens of the endoscope. In FIG. 6B, a dissection tip 146
includes an inner surface that tapers downward toward its distal
end and terminates in a flat surface 148 set at an angle from the
axis of the tip 146. In this case, incident light is reflected away
from the objective lens, which is typically placed along or near
the axis of the tip or dissector cannula. Finally, FIG. 6C
illustrates a dissection tip 150 having an internal taper that ends
at its distal-most extent in a backward wedge. This shape helps
deflect light from the fibers outward as opposed to directly
backward, thus reducing glare or reflection. All of these shapes
have the effect of reducing incident glare from the light fibers
back to the objective lens of the endoscope, thus improving the
user's view.
[0077] A common technique for vessel harvesting is to provide a
separate vessel dissector and vessel harvester, with the devices
being inserted one at a time in the body, typically through the
access trocar. Such is the configuration of the system in FIGS.
1A-1C. However, it is conceivable that the dissecting and
harvesting functions can be combined into a single device to save
time. For instance, FIG. 7 schematically illustrates the distal end
of an integrated endoscopic vessel dissector/harvester 160 of the
present invention having a blunt dissecting tip 162 with apertures
or recesses for the harvesting tools. More particularly, a vessel
holding tool 164 includes a tapered outer surface to match the
dissection tip 162 and is stationed within a recess therein.
Likewise, a vessel severing tool 166 having an outer surface that
conforms to the dissection tip 162 is retracted into a similar
recess. Each of the vessel holding tool 164 and vessel severing
tool 166 docks into recesses in the dissecting tip and has an
exterior shape that conforms to the conical exterior of the
dissecting tip so as to match its shape. The distal end of an
endoscope 168 is seen extending within the clear dissection tip
162. For dissection, the tools 164, 166 are retracted to conform to
the conical tip 162. Then, by manipulating the vessel holding tool
164 and vessel severing tool 166 (such as by axial and rotational
movement), selected side branches or primary vessels may be severed
and sealed immediately after a section of tunnel around the primary
vessel has been dissected. The vessel dissector/harvester 160 is
therefore advanced in stages along the primary vessel performing
both dissection and side branch management.
[0078] Another configuration that is contemplated to combine the
functions of the tissue dissector and vessel harvester is to
provide a dissection tip that can be detached from a cannula which
contains harvesting tools. For example, any of the conical tips
seen in FIGS. 6A-6C may be separable from a cannula that houses any
of the harvesting tools described below. With such a system the
user may alternate between dissection in ligation-transection as
desired. Furthermore, such a detachable conical tip may include an
opening therethrough to permit CO.sub.2 insufflation. Following
dissection, the cone is detached and insufflation may continue
through the open end of the cannula. Another alternative is to
provide a tether connecting the removable conical tip to the
cannula. In this way, the tip can be detached the remains in close
proximity to the distal end of the cannula for reattachment if
desired.
[0079] Occasionally, fatty or other tissue sticks to the outside of
the conical dissecting tip and prevents clear visualization
therethrough. FIG. 8 is a perspective view of an endoscopic vessel
dissector 170 of the present invention having a wiper blade or
finger 172 for clearing the distal dissecting tip 174 of tissue. In
this embodiment, the wiper blade 172 pivots about an axis 176 at
the beginning of the dissecting tip 174, or end of the cannula 178.
An actuating rod 180 controlled by a thumb lever 182 connects to
the wiper blade 172 and permits the user to alternately retract and
engage the blade with the exterior of the dissecting tip 174. The
tip 174 rotates about the axis of the cannula 178 when the user
turns a knob 184 at the proximal end of the device. The wiper blade
172 may be rigid or include a resilient scraper much like a vehicle
wiper blade. Various structural details of this arrangement are
left out but are well within those skilled in the art of medical
device design. Likewise, alternative arrangements are contemplated,
such as those shown in FIGS. 9 and 10.
[0080] FIGS. 9 and 10 are perspective views of the distal tip of
two alternative endoscopic vessel dissectors of the present
invention both having tip wiping capabilities. The dissector 190 in
FIG. 9 is similar to the dissector 170 of FIG. 8 in that it
includes a wiper blade or finger 192 for clearing tissue from the
conical dissecting tip 194. Instead of the tip rotating, however,
the blade 192 swivels about the axis of the device, such as through
its connection with a rotating outer sleeve or shaft 196 of the
elongated device. Again, details of the actuation of the shaft 196
are not shown, but are easily borrowed or surmised from existing
devices. FIG. 10 illustrates a dissector 200 fitted with an O-ring
wiper 202 over its conical dissecting tip. An actuation rod 204
displaces the O-ring wiper 202 longitudinally to wipe clean the
dissecting tip. The O-ring wiper 202 may be formed as a
loosely-wound metal or plastic spiral to facilitate expansion and
contraction around the tip. Of course, there are numerous other
configurations of wipers that may be displaced over the dissecting
tip, the present application only illustrating an exemplary
selection.
[0081] A further alternative to the tip wiping devices in FIGS.
8-10 is to add an energized cutting electrode to the wiper blade to
remove tissue via ablation. That is, instead of or in addition to
an inert rigid or resilient blade, a wire or bar electrode may be
incorporated to enable clearing of more stubborn tissue via
electrocautery. Although a specific structure is not shown, the
reader will understand that any of the wiper elements shown in
FIGS. 8-10 may represent such an energized wiper.
[0082] Still further, any of the conical tips illustrated herein,
including the simple prior art tip seen in FIG. 5A, may be fitted
with a system for clearing adhered tissue using fluid expelled from
the cannula. For example, an annular opening or a series of
separate circumferentially-spaced openings may be provided between
the conical tip and cannula, and streams of saline expelled from
the openings to knock tissue off the tip. Saline is particularly
suitable, although other fluids such as jets of CO.sub.2 gas maybe
used. The design intent would be to port the fluid so that it
flowed distally along the surface of the cone using the Coanda
effect in which a stream of fluid or gas will tend to hug a convex
contour when directed at a tangent to that surface.
Improvements to Vessel Holding Function
[0083] Once the target vessel has been exposed, such as with
dissection along its length, endoscopic vessel harvesting involves
passing an elongated device under visualization along the vessel to
sever and seal side branches. As mentioned above, numerous such
systems are currently available, including the system seen in FIG.
1A-1C. In that system, a vessel holding tool manipulates the target
vessel such that the side branches are positioned in front of a
severing and sealing tool. It is important to present both the side
branch and target vessel clearly so that the user does not
accidentally cut the target vessel instead of the side branch.
Also, it is desirable to retract the target vessel so that the side
branch can be cauterized as far away from the target vessel as
possible, to minimize risk of damage to the vessel from the cautery
tool (thermal spread).
[0084] FIGS. 11A and 11B are schematic side views of an endoscopic
vessel harvester of the prior art showing a vessel holding tool 210
and a complementary severing tool 212 axially extended from the
distal end of a cannula 214. The holding tool 210 typically has a
hook or other capturing feature for holding a primary vessel 216.
As the device advances, side branches 218 are encountered and the
system is manipulated to place them in line with the severing tool
212. There are certain drawbacks to this arrangement, in particular
the linear extension of the tools 210, 212, rendering them somewhat
awkward to maneuver for proper positioning of the side branches
218.
[0085] FIGS. 12A and 12B are schematic side views of an endoscopic
vessel harvester 220 of the present invention showing a vessel
holding tool 222 and a severing tool 224 extended from the distal
end of a cannula 226. To more easily accomplish straightening of
the side branches 218 in line with the severing tool 224, the
vessel holding tool 222 translates laterally. As seen in FIG. 12B,
the effect of angling the holding tool 222 radially outward is to
facilitate advancement of the tool along the primary vessel 216 as
well as to straighten the side branch 218 for more effective
cutting with the severing tool 224. A comparison of FIGS. 11A and
12A shows the increase in spacing between the holding and severing
tools, which exposes a greater length of side branch. The holding
tool 222 can be displaced laterally as shown by simply mounting it
on a curved or bent actuation rod, or via an angling mechanism, not
shown. In the case of a curved or bent support rod, the rod may be
flexible so as to retract within the cannula, and the farther the
tool 22 extends the greater the lateral displacement. In general,
the vessel holding tool 222 includes a support rod that extends
through the elongated cannula 226 and which is angled or is
configured to angle laterally at a location close to the distal end
of the tool.
[0086] FIG. 13 is a schematic side view of an alternative
endoscopic vessel harvester 230 of the present invention wherein a
vessel holding tool 232 includes a tip angled toward the vessel
severing tool 234. In this way, the holding tool 232 can position
the primary vessel 216 in line with the severing tool 234.
Ultimately, the primary vessel 216 will be severed at at least one
end after having been separated from its connecting side branches.
The holding tool 232 facilitates this step. It is conceivable that
the harvesters 220 and 230 can be combined such that the vessel
holding tool may alternately be angled away from the severing tool,
as seen in FIG. 12A, and toward the severing tool, as seen in FIG.
13. In other words, an articulating vessel holding tool may be
provided that has a support rod extending through the cannula which
is configured to articulate laterally at a location close to the
distal end of the tool and enable different angulations depending
on the situation.
[0087] FIGS. 14A-14C are several views of the transverse
displacement of an alternative vessel holding tool 240 upon
extension from the cannula 242 of an endoscopic vessel harvester of
the present invention. In this embodiment, the holding tool 240
mounts on the end of an elastic wireform 244 having a bend 246.
When retracted, the wireform 244 straightens within the delivery
channel 248. As the tool is extended, the bend 246 eventually
clears the end of the channel 248 causing lateral displacement of
the holding tool 240.
[0088] Another way to enable angling of the distal end of the
vessel holding tool is to provide a flexible support rod or
wireform and surround it with a rigid hypotube. Both structures may
longitudinally extend from the mouth of the cannula, and then
retraction of the hypotube from around the wireform angles the
vessel holding tool. In this embodiment, greater maneuverability of
the vessel holding tube is provided as it may be angled at various
axial locations rather than immediately as it exits the
cannula.
[0089] In a further advantageous feature, the vessel hook of the
vessel holding tool may incorporate a tapered blunt distal
dissecting surface for blunt dissection of tissue. The term "blunt"
surface in this context means one without sharp points or corners
and with some degree of taper to facilitate division or partition
of tissue planes. For example, the conical tips described herein
are considered blunt, and as a rule do not have sharp points. The
more rectilinear tissue holders of the prior art, however, are too
blunt and not well suited for tissue dissection.
[0090] It is very important to minimize obstructions in the field
of view--the more the device blocks the user's view of the tissue,
the greater the risk of avulsions and cautery mistakes. FIGS.
15A-15B are side and perspective views of an alternative vessel
holding tool 250 of the present invention that has a lower profile
than previous tools and thus provides greater visibility of its
operation. With reference back to FIG. 1B, the holding tool 62 of
the prior art includes two rods or supports that extend distally
from the cannula 50. These two rods present solid viewing obstacles
interposed between the endoscope objective lens and the actual
vessel holding operation. Desirably these obstacles are
minimized.
[0091] In one such lower profile holder, the vessel holding tool
250 has a single main rod or support 252 extending distally from
the distal end of the cannula 254 that carries a vessel hook 256.
The hook 256 is shaped to partially surround the primary vessel and
manipulate it to present a side branch to an associated vessel
severing tool (not shown). FIG. 15B illustrates the extension of a
locking member 258, which can be, for example, a concentric or
telescoping extension of the main rod 252. The hook 256 may be
substantially C-shaped so as to partially surround the vessel, and
the extension of the locking member 258 closes the remaining open
side so that the vessel is completely surrounded and captured
therein. In this way, a vessel may be securely held by the holding
tool 250 without risk of dislodgment yet the view from the
objective lens is maximized by removal of one of the support
rods.
[0092] FIGS. 16A-16B illustrate a further vessel holding tool 260
of the present invention formed of thin wire, also to reduce its
profile, reduce impediments to endoscopic viewing, and thus
increase visibility and accuracy of the operation. The tool 260
extends from the cannula 262 and includes a hook portion 264 formed
of a single wire, and a translating locking member 266 formed of
another wire or pin. Again, with the locking member 266 extended
the holding tool 260 completely encloses the vessel for
manipulation and severing. Although there are two support rods
extending from the cannula, they are extremely thin and present a
minimum viewing obstacle to the objective lens. Desirably, the
holding tool 260 is formed of metal or plastic wires having a
thickness of between about 0.5 mm and 1.0 mm.
[0093] FIG. 17A is a partial sectional view of a vessel holding
tool 270 of the present invention incorporating a mechanism for
preventing vessel avulsion. These types of vessel holding tools are
used to hook the primary vessel and move down its length,
occasionally stopping to sever side branches. If the tool is moved
too fast or too hard when a side branch is reached, damage can
occur. The tool 270 includes a hook portion 272 that is mounted on
the end of a displacement rod 274 extending from the cannula 276.
Within the cannula 276, the rod 274 passes through a friction
collar 278 that acts as a damped slip mechanism between the hook
portion 272 and the cannula 276. That is, if the hook portion 272
experiences resistance as it travels down the length of the primary
vessel, further movement of the cannula 276 will not further pull
or push on the vessel, but instead will cause damped relative
movement between the cannula and the hook portion.
[0094] In a similar manner, FIG. 17B shows a vessel holding tool
280 with a hook portion 282 mounted on a displacement rod 284
extending from a cannula 286. A slip mechanism 288, in this case a
piston/cylinder/spring arrangement, permits damped relative
tool/cannula movement in case the hook portion catches on any body
structure and generates a reaction force in the displacement rod
284 in opposition to movement of the cannula 286. Of course, the
two examples of FIGS. 17A and 17B are merely exemplary and other
clutch mechanisms performing a similar function can be
substituted.
[0095] Finally, FIG. 18 illustrates still another vessel holding
tool 290 of the present invention having an enlarged locking member
292 for better positioning of the vessel 294. That is, the vessel
294 is first retained within the hook portion 296 then a locking
member 292 is axially extended to capture it. Earlier locking
members were thin rods or pins that left a relatively large space
within the mouth of the hook portion 296, and thus especially
smaller vessels could easily move around. In this embodiment, the
locking member 292 is shaped as a large wedge that limits the space
in which the vessel 294 is held and thus increases its stability
prior to the side branch severing operation. In terms of relative
size, the locking member 292 when extended desirably reduces the
space within the mouth of the hook portion 296 by about 50%. The
tapered leading edge helps prevent pinching of the vessel as the
locking member 292 extends.
Improvements to Vessel Severing Function
[0096] Numerous instruments are known which coagulate, seal, join,
or cut tissue, and which are suitable, for example, for severing a
target vessel from surrounding side branches and securing the
separated ends to stanch bleeding. Such devices typically comprise
a pair of tweezers, jaws or forceps that grasp onto and hold tissue
therebetween. The devices may operate with a heating element in
contact with the tissue, with an ultrasonic heater that employs
frictional heating of the tissue, or with a mono- or bi-polar
electrode heating system that passes current through the tissue
such that the tissue is heated by virtue of its own electrical
resistance. The devices heat the tissue to temperatures such that
the tissue is either "cut" or "sealed", as follows. When tissue is
heated in excess of 100.degree. Celsius, the tissue disposed
between the tweezers, jaws or forceps will be broken down and is
thus, "cut". However, when the tissue is heated to temperatures
between 50.degree. to 90.degree. Celsius, the tissue will instead
simply "seal" or "weld" to adjacent tissue. Monopolar and bipolar
probes, forceps or scissors use high frequency electrical current
that passes through the tissue to be coagulated. The current
passing through the tissue causes the tissue to be heated,
resulting in coagulation of tissue proteins. In the monopolar
variety of these instruments, the current leaves the electrode and
after passing through the tissue, returns to the generator by means
of a "ground plate" which is attached or connected to a distant
part of the patient's body. In a bipolar version of such an
electro-surgical instrument, the electric current passes between
two electrodes with the tissue being placed or held between the two
electrodes as in the "Kleppinger bipolar forceps" used for
occlusion of Fallopian tubes. A new development in this area is the
"Tripolar" instrument marketed by Cabot and Circon-ACMI which
incorporates a mechanical cutting element in addition to monopolar
coagulating electrodes. A similar combined sealing and mechanical
cutting device may also be known as a tissue "bisector," which
merges the terms bipolar cautery and dissector. One tissue bisector
is packaged for sale as an element of the VASOVIEW.RTM. 6 vessel
harvesting systems by Guidant Corporation of Santa Clara, Calif. In
ultrasonic tissue heaters, a very high frequency (ultrasonic)
vibrating element or rod is held in contact with the tissue. The
rapid vibrations generate heat causing the proteins in the tissue
to become coagulated. Conductive tissue welders usually include
jaws that clamp tissue therebetween, one or both of which are
resistively heated. In this type of instrument, no electrical
current passes through the tissue, as is the case for monopolar or
bipolar cautery.
[0097] It should be understood that any of these prior instruments
for severing and/or sealing vessels, or those described below, may
be combined with the various components of the vessel harvesting
systems described herein. It should also be understood that various
configurations of monopolar, bipolar, or other type of electrodes
may be provided on the vessel severing/sealing tools described
below. Those of skill in the art will understand that the
particular shape and size of the electrodes, and their arrangement
with respect to other electrodes, will dictate the power
requirements and operational constraints. Further, some embodiments
described herein may work better with one or other type of
electrodes or heating elements, though such optimal permutations
will not be exhaustively described.
[0098] One important function of any severing tool is to manage
vessels of different sizes without extra effort on the part of the
user. This is particularly important for bipolar cautery tools
which must realize good tissue contact with both electrodes for
optimum performance. For fixed electrodes (such as the "bisector"
described above), small vessels are more difficult to cauterize;
users are taught to position the vessel between the bisector
electrodes, and then to rotate the bisector to ensure good contact
with both electrodes. Merely decreasing the distance between the
electrodes for better contact may prevent use on larger vessels.
Moveable electrodes, or jaws, are on solution but require some
additional effort to avoid clamping too hard on the vessel, which
may result in damage thereto.
[0099] FIGS. 19A and 19B are schematic views of an alternative
vessel severing tool 300 of the present invention having two wire
electrodes 302 overlapping across a large gap G defined by a mouth
for receiving a vessel. In contrast with some earlier devices, the
gap G is large enough to receive both the side branches and the
primary vessel, preferably between about 4.0 mm and 6.0 mm, more
preferably about 6.0 mm. The wire electrodes 302 that overlap in a
crossing pattern across the gap G are resilient and flex to
automatically accommodate widely varying sizes of vessel. In this
context "accommodate" means to contact opposite sides of the
vessel. This is especially important to ensure good contact with
very small vessels. The vessel severing tool 300 desirably
accommodates vessels having diameters that range from between 0.5
mm and 6.0 mm. In a variation of the embodiment of FIGS. 19A and
19B, a vessel severing tool has a mouth defined by facing vessel
contacts that flex apart upon receiving a vessel therebetween,
though the contacts may not be electrodes. Any cutting tool may be
combined with a variably-sized mouth to secure different sized
vessels.
[0100] Desirably, the wire electrodes are made of stainless steel
and have a wire thickness of between about 0.5 mm and 1.0 mm so
that they easily flex to permit a vessel to move farther into the
gap than if they were more rigid and thus ensure good current
contact with the vessel. Also, as seen in FIG. 19B, the wire
electrodes 302 are set at different radial distances from the
central axis of the tool out of contact with each other, thus
providing the separation needed for bipolar coagulation. One
distinct advantage of the vessel severing tool 300 over prior
designs is its ability to automatically accommodate varying sizes
of vessel. That is tools having movable jaws, for example, can
adapt to various vessel diameters but only upon careful user
manipulation. The tool 300 thus speeds up the entire vessel
harvesting operation, which may involve severance of numerous
vessels.
[0101] FIG. 20 is a side view of an alternative vessel severing
tool 310 of the present invention having a stepped vessel-receiving
mouth 312. The stepped shape of the mouth 312 accommodates a wider
range of vessel sizes while ensuring good contact with tissue
cautery electrodes (not shown) provided, for example, on opposite
sides of the mouth. In contrast to a fixed V-shaped gap, the
stair-stepped shape of the mouth 312 presents several progressively
smaller intermediate gaps with generally parallel sides that
provide regions of constant width surface contact with the vessel.
Also, the step to the next smaller intermediate gap contacts the
vessel. This "bracketing" of the vessel helps ensure a good seal
without the risk of excessive pinching. The vessel severing tool
300 desirably accommodates vessels having diameters that range from
between 0.5 mm and 6.0 mm. In one embodiment, the mouth 312 of the
vessel severing tool 300 defines intermediate gaps having widths in
decreasing increments of 1.0 mm, for example 6-5-4 mm, or 5-4-3
mm.
[0102] Although immovable severing/sealing tools may prove suitable
in certain applications, often it is desirable to apply certain
amount of pressure to the vessel with movable jaws, for example.
FIGS. 21A-21B illustrate a vessel severing tool 320 of the present
invention having jaws 322 that are resiliently biased away from one
another and which can be partially closed. The jaws 322 may carry
bipolar or monopolar electrodes. A pull wire or control rod 324
connects to a closure ring 326 and enables axial displacement
thereof for closing the jaws 322, as seen in FIG. 21B.
Visualization of the severing/sealing operation then enables the
user to vary the extent of closure of the jaws 322, and thus the
magnitude of pressure applied. The jaws 322 cannot completely close
and have a minimum gap therebetween as see in FIG. 21B of between
about 0.5 mm and 1.0 mm. This minimum is calibrated so that the
tool 320 accommodates even the smallest expected vessels, yet
excessive clamping of even much larger vessels is reduced because
there is no contact between the jaws 322.
[0103] FIG. 22 is a side view of a vessel severing tool 330 having
stationery jaws 332 and rotary blades 334 incorporated thereon. The
blades 334 may be connected to electric power and function as
cutting electrodes, or may be inert knife blades, that work in
conjunction with separate sealing electrodes (not shown) provided
on the jaws 332. This configuration removes the need for providing
electrodes that perform dual severing and sealing functions, which
frees the designer to optimize the sealing electrodes.
[0104] FIGS. 23A-23B are two side views of a vessel severing tool
340 having a movable blade 342 that desirably works in cooperation
with electrodes (not shown) that seal the cut vessel. A control rod
344 connects to displace the blade 342 toward an anvil 346 provided
on a hook portion 348 of the tool 340. The blade 342 and
cooperating anvil 346 are slightly angled as shown to sever the
vessel with a shearing action. A mechanical cutter such as this may
be desirable in contrast to electrocautery transection which can be
time-consuming, may inflict thermal damage on the tissue, and may
not be entirely effective.
[0105] FIG. 24 schematically illustrates a vessel severing tool 350
having a system for clearing tissue therefrom using gas jets.
Occasionally, the repeated application of heat or electricity to
tissue creates sticking or burning of the tissue to the electrodes.
One means to resolve this problem is to provide tubing 352
extending adjacent a severing/sealing tool 354. The tubing 352
terminates close to the electrodes or cutting blades of the tool
354 and jets of gas such as CO.sub.2 may be expelled from the open
ends or from special nozzles to knock tissue off the tool. CO.sub.2
is particularly suitable because it is already used for
insufflation of the body cavity, although other fluids such as
saline may also be used.
[0106] FIGS. 25A-25B are front and top section views, respectively,
of an alternative vessel severing tool 360 capable of translating
transversely as well as longitudinally. An electrode-carrying
member 362 translates circumferentially within an arcuate slot 364,
and may be actuated by a control rod 366. This arrangement greatly
enhances the maneuverability of the tool and consequently the
options for the user.
[0107] In FIG. 26, a severing/sealing tool 370 shown from its front
end within an insufflated tunnel 372 includes a cannula having a
pair of partial tubular vessel shields 374 extending therefrom
around a primary vessel 376. The gaps between the shields 374
accommodate side branches 378 from the primary vessel 376. A
tubular cutting element 380 that may be axially displaced from the
cannula surrounds the shields 374. The user positions the shields
around a vessel 376 with the side branches 378 as shown, and then
advances the cutting element 380. The shields 374 protect the
vessel 376 and ensure adequate stump length of the transected
branches 378. The cutting element 380 may be a tubular knife blade
or an electrode designed to cut.
[0108] FIGS. 27A-27B are side and top views of a vessel
severing/sealing tool 400 that incorporates several moving parts.
The tool 400 includes a pair of fork-shaped electrodes 402 spaced
laterally apart so as to create a gap within which moves a severing
blade 404. A vessel capturing mandible 406 also moves within the
gap between the electrodes 402. In use, a vessel 408 is seen
positioned within the tines of the fork-shaped electrodes 402 and
prior to capture by the mandible 406. The mandible 406 has a
serrated distal finger to securely capture the target vessel within
the tines. Upward movement of the mandible traps the vessel 408 at
which time energy may be applied by the electrodes 402 to begin the
coagulation process. Subsequently, the blade 404 actuates downward
and severs the vessel 408. Mechanisms for moving both the blade 404
and mandible 406 are not shown, although both have angled or
arcuate proximal surfaces that can be utilized to cam against a
delivery cannula and displace the elements toward one another upon
their proximal retraction using a control rod, for example.
[0109] FIGS. 28A-28B are two schematic views of a vessel
severing/sealing tool 420 incorporating a side-opening
cutter/sealer 422. In the enlarged view of FIG. 28B, the cutter 422
comprises an upper electrode 424 and a lower electrode 426
separated across a slot 428. The upper and lower electrodes 424,
426 may be bipolar, and the slot 428 may accommodate a knife blade
or other such cutting device. FIG. 29 is an endoscopic view showing
the use of the tool 420 severing a side branch 430 from a primary
vessel 432.
[0110] Finally, FIG. 30 is a top plan view of an alternative
severing tool 440 which has a first ring-shaped electrode 442
extending from a cannula structure 444, and the second coil-shaped
electrode 446 concentrically arranged around the first
electrode.
[0111] While the invention has been described in its preferred
embodiments, it is to be understood that the words which have been
used are words of description and not of limitation. Therefore,
changes may be made within the appended claims without departing
from the true scope of the invention.
* * * * *
References