U.S. patent application number 15/046508 was filed with the patent office on 2016-08-25 for apparatus, system and method for excision of soft tissue.
This patent application is currently assigned to Hemostatix Medical Technologies, LLC. The applicant listed for this patent is Hemostatix Medical Technologies, LLC. Invention is credited to Brad Beale, Philip E. Eggers, Jerry Van Eyck.
Application Number | 20160242836 15/046508 |
Document ID | / |
Family ID | 56690160 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160242836 |
Kind Code |
A1 |
Eggers; Philip E. ; et
al. |
August 25, 2016 |
Apparatus, System and Method for Excision of Soft Tissue
Abstract
Disclosed is a soft tissue excision apparatus having a handle
and an elongated blade support member extending from the handle.
The distal end of blade support member includes a first thermally
conductive blade support arm and a second thermally conductive
blade support arm. An electrically heatable blade is supported at
and electrically isolated from the distal ends of the two thermally
conductive blade support arms. A first electrically conductive lead
extends from the proximal end of the thermally conductive blade
support member to a first blade heater contact pad. A second
electrically conductive lead extends from the proximal end of the
thermally conductive blade support member to a second blade heater
contact pad. First and second electrically conductive flexible
leads extend from the proximal end of the thermally conductive
blade support member to a controller.
Inventors: |
Eggers; Philip E.; (Dublin,
OH) ; Beale; Brad; (Lakeland, TN) ; Van Eyck;
Jerry; (Mill Creek, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hemostatix Medical Technologies, LLC |
Bartlett |
TN |
US |
|
|
Assignee: |
Hemostatix Medical Technologies,
LLC
Bartlett
TN
|
Family ID: |
56690160 |
Appl. No.: |
15/046508 |
Filed: |
February 18, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62119312 |
Feb 23, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/1407 20130101;
A61B 2018/00875 20130101; A61B 2018/1412 20130101; A61B 18/149
20130101; A61B 2018/00642 20130101; A61B 2018/00327 20130101; A61B
2018/00178 20130101; A61B 2018/00702 20130101; A61B 18/08 20130101;
A61B 2018/00607 20130101 |
International
Class: |
A61B 18/08 20060101
A61B018/08 |
Claims
1. An apparatus for the excision of soft tissue in one or more of
the throat, oropharynx, nasopharynx, or larynx of humans,
comprising: [a] a handle; [b] an elongated blade support member
having a distal end and a proximal end, and extending from the
handle; [c] the distal end of blade support member including a
first thermally conductive blade support arm having a distal end
and a proximal end, and a second thermally conductive blade support
arm having a distal end and a proximal end; [d] an electrically
heatable blade supported at and electrically isolated from the
distal ends of the first and second thermally conductive blade
support arms; [e] a first electrically conductive lead extending
from the proximal end of the thermally conductive blade support
member to a first blade heater contact pad; [f] a second
electrically conductive lead extending from the proximal end of the
thermally conductive blade support member to a second blade heater
contact pad; and [g] a controller, wherein the first and second
electrically conductive flexible leads extend from the proximal end
of the thermally conductive blade support member to the
controller.
2. The apparatus of claim 1, wherein the heatable blade has at
least one straight cutting edge for excising soft tissue.
3. The apparatus of claim 1, wherein the heatable blade has at
least one triangular shaped cutting edge for excising soft
tissue.
4. The apparatus of claim 1, wherein the heatable blade has an
electrically conductive heating element that incorporates a
conductive material having a high temperature coefficient of
resistance of at least 400 ppm per degree C.
5. The apparatus of claim 1, wherein the heatable blade has at
least one cutting edge having a tip, wherein the heatable blade is
covered with a non-stick coating except at the cutting edge
tip.
6. The apparatus of claim 1, wherein the elongated blade support
member is malleable.
7. The apparatus of claim 1, wherein the electrically conductive
heating element of the heatable blade incorporates a ferromagnetic
material having a Curie temperature in the range from 150 C to 600
C.
8. The apparatus of claim 1, wherein first and second thermal
barrier members are positioned between the heatable blade and the
first and second distal ends of the thermally conductive blade
support arms, respectively, to reduce conduction of heat.
9. An apparatus for the excision of soft tissue in one or more of
the throat, oropharynx, nasopharynx, or larynx of humans,
comprising: [a] a handle; [b] an elongated blade support member
having a distal end and a proximal end, and extending from the
handle; [c] distal end of the blade support member including first
and second thermally and electrically conductive blade support arms
having distal ends and proximal ends; [c] the first thermally and
electrically conductive blade support arm being electrically
isolated from the second thermally and electrically conductive
blade support arm; [d] an electrically heatable blade supported at
the distal ends of the first and second thermally and electrically
conductive blade support arms; [e] a first electrically conductive
lead extending from and in electrical communication between the
distal end of the first thermally and electrically conductive blade
support arm and a first blade heater contact pad; [f] a second
electrically conductive lead extending from and in electrical
communication between the distal end of second thermally and
electrically conductive blade support arm and a second blade heater
contact pad; and [g] a controller; and [h] third electrically
conductive flexible leads extending between the proximal ends of
first and second thermally and electrically conductive blade
support arms and the controller.
10. The apparatus of claim 9, wherein the heatable blade has at
least one straight cutting edge for excising soft tissue.
11. The apparatus of claim 9, wherein the heatable blade has at
least one triangular shaped cutting edge for excising soft
tissue.
12. The apparatus of claim 9, wherein the electrically conductive
heating element of the heatable blade incorporates a conductive
material having a high temperature coefficient of resistance of at
least 400 ppm per degree C.
13. The apparatus of claim 9, wherein the heatable blade has at
least one cutting edge having a tip, wherein the heatable blade is
covered with a non-stick coating except at the cutting edge
tip.
14. The apparatus of claim 9, wherein the elongated blade support
member is malleable.
15. The apparatus of claim 9, wherein the electrically conductive
heating element of the heatable blade incorporates a ferromagnetic
material having a Curie temperature in the range from 150 C to 600
C.
16. The apparatus of claim 9, wherein first and second thermal
barrier members are positioned between the heatable blade and the
first and second distal ends of the thermally conductive blade
support arms, respectively, to reduce conduction of heat.
17. An apparatus for the excision of soft tissue in one or more of
the throat, oropharynx, nasopharynx, or larynx of humans,
comprising: [a] a handpiece comprising an elongated blade support
member having a proximal end and a distal end, first and second
blade support arms, and a heatable blade with at least one cutting
edge for excising soft tissue; [b] first and second electrical
leads extending from the proximal end of the blade support member
to first and second blade heater contact pads, respectively; [c] a
controller for maintaining a temperature of the heatable blade to
an operator-selected set-point temperature; and [d] a cable
extending from and in electrical communication with the first and
second electrical leads at the proximal end of the blade support
member to the controller.
18. The apparatus of claim 17, wherein the heatable blade
incorporates a conductive material having a high temperature
coefficient of resistance of at least 400 ppm per degree C.
19. The apparatus of claim 17, wherein the heatable blade
temperature is in the range of 70 C to 600 C.
20. The apparatus of claim 17, wherein the heatable blade has a
heating element that incorporates a ferromagnetic material having a
Curie temperature in the range from 150 C to 600 C.
21. The apparatus of claim 17, having a footpedal attached to the
controller, wherein the footpedal comprising a first pedal to
activate excision heating of the heatable blade during tissue
excision and a second pedal to activate coagulation heating of the
heatable blade to effect coagulation of blood vessels underlying
excised soft tissue.
22. The apparatus of claim 17, wherein the distal end of the blade
support arms having a tissue contact surface that carry first and
second electrodes, wherein third and fourth electrical leads extend
from the proximal end of the blade support member to the first and
second electrodes, respectively; and a cable extends from the
first, second, third and fourth electrical leads at proximal end of
blade support member within handpiece to the controller.
23. A method for the excision of soft tissue in one or more of the
throat, oropharynx, nasopharynx, or larynx of humans, comprising
the steps of: [a] inserting a blade support member and heatable
blade into a patient's mouth or throat while positioning the
heatable blade adjacent to the soft tissue to be excised, wherein
the heatable blade has a cutting edge; [b] applying power to the
heatable blade for sufficiently elevating the heatable blade to an
elevated temperature to seal severed blood vessels during soft
tissue excision; [c] while applying power, also advancing the
cutting edge of the elevated temperature heatable blade through the
soft tissue to be excised to effect tissue excision while
minimizing bleeding therefrom; and [d] removing the heatable blade
and blade support member from the patient's mouth or throat.
24. The method of claim 23, wherein the heatable blade has a first
surface and further comprising the step of urging the first surface
of the elevated-temperature heatable blade against a surface of the
tissue layer underlying the excised tissue to effect coagulation
and sealing of blood vessels severed during excision.
25. The method of claim 23, wherein the distal ends of the first
and second blade support members carry a pair of spaced-apart
electrodes, and the method further comprises the step of measuring
electrical impedance of tissue located between the electrodes to
identify when maximum tissue impedance has been achieved.
26. The method of claim 23, for excision of tonsil tissue.
27. The method of claim 23, for excision of adenoid tissue.
28. The method of claim 23, wherein the elevated temperature
heatable blade is advanced in step (c) at an angle of between about
15 and 30 degrees relative to the forward direction thereof to
reduce the force required for soft tissue excision.
Description
FIELD
[0001] The field of this disclosure is an apparatus, system and
method for the incision of soft tissue in humans using a
mechanically sharp blade with concurrent tissue heating to effect
tissue incision with minimal bleeding. By way of example, the
apparatus, system, and method of the present disclosure
advantageously may be applied to surgical adenoidectomy and
tonsillectomy.
BACKGROUND
[0002] The tonsils and adenoids are generally located in the back
of the nose and throat. The tonsils and adenoids serve to collect
and identify bacteria and/or viruses entering the body. Once
identified, the immune system is activated to produce antibodies
that target the invading bacteria and/or viruses to reduce or
eliminate the bacteria and/or virus-induced infection. As bacteria
and viruses are incorporated within the tonsils and adenoids, these
tissues are able to deconstruct the bacteria and/or virus cells
wall and release cellular contents to areas of the body that
produce antibodies responsive to the cellular contents. Repeated
inflammation of the tonsils and adenoids can overwhelm the
capability of the tonsils and/or adenoids to deconstruct the
bacteria and/or viruses incorporated within; thereby, resulting in
bacterial and/or viral growth within the tissues of the tonsils
and/or adenoids. The abnormal accumulation of bacteria and/or virus
media within the tonsils and/or adenoids can induce repeated
infections such as tonsillitis or ear infections. If antibiotic
treatment fails to reduce or eliminate the level of growth of
bacteria within the tonsils and/or adenoids, often leading to
swelling to the point of airway obstruction, then excision of the
tonsils and/or adenoids may be necessary.
[0003] The devices and techniques used for tonsillectomy and
adenoidectomy procedures depend on the type and amount of tissue to
be removed and surgeon preference. The tonsillectomy and
adenoidectomy procedures routinely are performed together. A widely
used method for tonsillectomy and adenoidectomy has utilized a
sharp blade to effect mechanical excision of the tonsil and/or
adenoid tissue. Although excision with a mechanically sharp blade
provides for the precise removal of the intended tonsil and/or
adenoid tissue it unavoidably results in heavy bleeding from the
tissue bed underlying the tonsils and/or adenoids. Such heavy
bleeding is staunched using tamponade (often combined with a
coagulation inducing chemical agent) and/or the use of
electrosurgery to locally heat and seal the excised open blood
vessels. Although the use of electrosurgery to staunch the bleeding
associated with tissue excision using a mechanically sharp blade
serves to reduce intra-operative blood loss, it contributes to
increased post-operative pain due to spread of the thermal injury
to adjacent tissue and nerves due to the flow of electrosurgical
currents beyond the surface of excision.
[0004] Another approach is the use of electrosurgery for both the
excision of the adenoids and/or tonsils, as well as the
post-excision application of electrosurgery-induced arcs to seal
severed blood vessels and desiccate the underlying tissue bed to
minimize further post-operative bleeding. Although the use of
electrosurgery to staunch the bleeding associated with tissue
excision using electrosurgical cutting serves to reduce
intra-operative blood loss, it contributes to increased
post-operative pain due to the spread of the thermal injury to
adjacent tissue and nerves due to the flow of electrosurgical
currents beyond the surface of excision.
[0005] Yet another approach is the volumetric removal of tonsil
and/or adenoid tissue through the use of molecular disintegration
of the targeted tissue. Although the use of molecular
disintegration to volumetrically remove tissue and apply very
localized tissue heating using a bipolar electrode configuration
serves to reduce both bleeding and post-operative pain, it is
unavoidably a much slower process than methods used to excise the
tonsils and/or adenoids.
[0006] Prior art devices for the excision of tonsil and/or adenoid
tissue are associated with disadvantageous post-operative bleeding,
patient discomfort, and/or prolonged procedure times. It would,
therefore, be advantageous to provide an apparatus, system, and
method that provides for the precise and rapid excision of tonsils
and/or adenoids while minimizing both intra-operative and
post-operative bleeding, as well as minimizing post-operative
pain.
BRIEF SUMMARY
[0007] The limitations of prior art devices for the excision of
adenoid tissue are overcome by the apparatus, system, and method of
the present disclosure comprising [a] a temperature controller, [b]
a removably attachable flexible cable in electrical communication
with both the temperature controller and a handpiece, and [c] a
handpiece with a surgically sharp cutting edge, comparable to
existing cold scalpels, combined with a heatable blade covered by a
non-stick coating to minimize intra-operative and post-operative
bleeding, as well as to minimize the avulsion of the sealing layer
formed over transected blood vessels due to sticking of tissue to
the heatable blade. Prior-art surgically sharp, heatable blades
used for the incision and excision of mammalian tissue are disposed
at the distal end of a support member or shank to minimize heat
conduction into a hand piece and only the heated portion of the
blade comes in contact with tissue. By way of example of prior-art
surgically sharp, heatable blades used for the incision and
excision of mammalian tissue, see U.S. Pat. Nos. 5,308,311 and
8,475,444, incorporated herein by reference.
[0008] In the present disclosure, a resistively heatable blade
comprising a surgically sharp edge (i.e., incorporating a blade
with a mechanically sharp cutting edge) is supported in close
proximity at either end of the heatable blade by a first and second
support arm of a curette. In order to avoid iatrogenic injury to
healthy tissue adjacent to the site of the intended excision of
adenoid tissue, the exposed surfaces of the first and second
curette blade support arms must be maintained at a temperature
below the threshold for thermal injury at all times during a
surgical procedure. This critical requirement results from the fact
that the intended use of an adenoidectomy curette in the confined
region of the throat of the patient (the curette having a heatable
blade operating at, by way of example, 250.degree. C.) involves
unavoidable contact of the blade support arms with adjacent vital
tissue that should not be injured.
[0009] By way of example, the surgically sharp, heatable blade of
the present disclosure may comprise a pre-sharpened surgical-grade
metal blade substrate (e.g., heat treated and hardened martensitic
stainless steel) coated with a first layer of electrically
insulative material onto which is disposed a second layer of
electrically resistive material exhibiting a large temperature
coefficient of electrical resistance (e.g., copper or silver heater
material) to form an electrically resistive heating element. The
electrically resistive heating element section (e.g., a serpentine
pattern of electrically resistive material) is disposed on one side
of the central portion of the blade and terminated by first and
second heater contact pads at either end of the heating element
section. The first and second contact pads are positioned so that
they are in electrical communication with corresponding first and
second lead contact pads disposed on the first surface of first and
second thermal barrier members. Third and fourth lead contact pads
are disposed on the opposite sides of the first and second thermal
barrier members, respectively, to enable electrical communication
with the first and second blade support arms, respectively. The
first and third lead contact pads on the first thermal barrier
member are in electrical communication using a copper plated
through hole commonly referred to as a via. Likewise, the second
and fourth lead contact pads on the second thermal barrier member
are in electrical communication using a copper plated through hole
or via. Based on this example configuration and construction, the
first and second thermal barrier members reduce the level of heat
conduction from either end of the attached heatable blade to the
first and second blade support arms. In addition to disposing a low
thermal conductivity thermal barrier member between the heatable
blade and the blade support arms to reduce the amount of heat
conducted from the heatable blade to the distal ends of the first
and second blade support arms, the cross-sectional area and thermal
conductivity of the first and second support arms are selected to
maximize the conduction of heat away from the distal ends of the
blade support members. As a result of the high thermal conductance
of the blade support arms, the heat conducted from the heatable
blade is distributed over an extended length of the proximal
sections of the blade support arms and their integral support shaft
member, thereby maintaining the temperature of the exposed surfaces
of the blade support arms below the temperature of irreversible
thermal injury to tissue (e.g., preferably at a temperature below
about 50.degree. C. based on the expected duration of temperature
contact during a surgical procedure).
[0010] In the above example, the temperature of the heating element
is controlled to account for the significant difference in the rate
of heat dissipation from the blade when it is in contact with air
and tissue during tissue incision. The contact of the blade only
with air represents a relatively low rate of heat dissipation due
to the thermally insulative properties of air associated with
conduction and convection heat transfer and relatively low rate of
radiation heat transfer at the intended elevated blade
temperatures. In contrast, the contact of the blade with tissue
represents a significantly higher rate of heat dissipation than
contact with air. To accommodate the avoidably large differences in
heat dissipation during the intended use of the heatable blade
during the intended surgical procedure, temperature feedback
control is essential to maintain the blade within acceptable
temperature range to avoid [a] excessively high temperatures when
in contact with air (e.g., temperatures that could damage the
non-stick coating and/or thermal barrier members) and [b]
excessively low temperatures when in contact with tissue thereby
limiting the intended transfer of heat to tissue at the cutting
edge to seal incised blood vessels and thereby limit
intra-operative and post-operative bleeding. The required
temperature feedback control may be achieved in the present
disclosure by any one of a number of feedback control processes or
intrinsic temperature autoregulation mechanisms. By way of example
but not limiting, temperature feedback control may be accomplished
with the use of heating element comprising a material exhibiting a
high temperature coefficient of resistance (e.g., heating element
comprising copper, nickel, or silver). The controller uses the
initially measured room-temperature resistance and known
temperature coefficient of resistance of the heating element to
determine the set-point heater resistance corresponding to the
selected set-point temperature. This temperature control process is
referred to hereinafter as resistance-feedback based temperature
control.
[0011] In another embodiment of the present disclosure, the
operating temperature of the heatable blade of the present
disclosure may be controlled with the use of one or more
temperature sensors (e.g., thermocouples) attached at one or more
locations on heatable blade to regulate the application of power to
one or more heater segments to maintain the user selected operating
temperature. This temperature control process is commonly referred
to hereinafter as temperature-sensor based feedback control. The
use of temperature-sensor based feedback control may be combined
with the use of a resistive heating element disposed on the
mechanically sharp heatable blade or may be combined with the
direct heating of the heatable blade by the flow of current through
the length of the heatable blade. By way of example of current-flow
induced resistive heating of the blade member, the blade may
comprise a material exhibiting a high electrical resistivity and/or
the application of a high frequency current to confine current flow
to the surface layer of the blade, a heating effect commonly known
as skin effect heating, as described in U.S. Pat. No. 4,701,587 and
incorporated herein by reference. As specified in U.S. Pat. No.
4,701,587, skin effect heating can be enhanced through the use of a
thin layer overlaying the blade member substrate that exhibits a
higher electrical resistivity than the substrate blade member and
the thin layer overlaying the blade member substrate may include a
metal, metal alloy, metal ceramic, metal semiconductor, and/or
metal oxide.
[0012] In yet another embodiment of the present disclosure, the
operating temperature of the heatable blade of the present
disclosure may be controlled using a ferromagnetic or ferrimagnetic
blade member material or thin layer overlaying the blade member
substrate that exhibits a Curie temperature selected to correspond
to the pre-selected operating temperature of the heatable blade
(e.g., 250.degree. C.), thereby enabling the temperature to be
controlled in a narrow range at or below the intrinsic Curie
temperature of the blade member or the thin layer overlaying the
blade member substrate. This temperature control process is
referred to hereinafter as Curie temperature autoregulation based
temperature control and is described in U.S. Pat. No. 4,701,587,
which is incorporated herein by reference. The power source used in
combination with Curie temperature autoregulation based temperature
control commonly incorporates the use of a constant, high frequency
current, typically ranging from, but not limited to, frequencies of
about 5 megahertz to 24 gigahertz.
[0013] In yet another embodiment of the present disclosure, a
ferromagnetic or ferrimagnetic blade member material or thin layer
overlaying the blade member substrate may be selected so that the
operating temperature of the heatable blade is below the Curie
temperature of the ferromagnetic or ferrimagnetic blade member or
thin layer overlaying the blade member substrate. In this
alternative embodiment, a temperature sensor is positioned in
thermal communication with heatable blade to measure, regulate, and
maintain the temperature of heatable blade within a narrow range
around a pre-selected set-point temperature. The heating current
induced within the ferromagnetic or ferrimagnetic coating is a
variable electrical current level to effect temperature feedback
control of the heatable blade temperature. In this embodiment, the
frequency ranges from about 4 megahertz to 24 gigahertz to induce
skin effect heating wherein the current flow is predominantly
confined to the surface or "skin" layer of the ferromagnetic or
ferrimagnetic material.
[0014] In yet another embodiment of the present disclosure, first
and second electrodes are disposed at the distal ends of the
heatable blade and adjacent to the distal ends of the blade support
arms to enable the intra-operative measurement of electrical
impedance of the tissue located between the first and second
electrodes. The level of electrical impedance of the tissue located
between the first and second electrodes is measured using a current
having a frequency of, but not limited to, 50 kilohertz to about 1
megahertz. The measured level of electrical impedance in the tissue
located between the ends of and underlying the heatable blade is
used to assess the level of tissue desiccation and associated
hemostasis within the underlying tissue. The higher the level of
measured electrical impedance between the first and second
electrodes, the greater the extent of tissue desiccation and
associated hemostasis. The measured electrical impedance of the
tissue underlying the heatable blade can then be used to determine
if a sufficient level of hemostasis has been attained to indicate
the completion of the surgical procedure. In the event the measured
level of electrical impedance of the underlying tissue is above
some predetermined threshold, then the underside of the heatable
blade surface adjacent to the tissue and operating at an elevated
temperature (e.g., 250.degree. C.) can continue to be urged against
the underlying tissue to achieve a still greater degree of
desiccation and associated hemostasis.
[0015] In yet another embodiment of the present disclosure, the
first and second electrodes disposed at the distal ends of the
heatable blade and adjacent to the distal ends of the blade support
arms may be employed for both [a] the intra-operative measurement
of electrical impedance of the tissue located between the first and
second electrodes and [b] the conduction of high frequency current
through the underlying tissue to effect resistive heating of the
underlying tissue. This method of tissue heating by the passage of
high frequency current directly through tissue is commonly known as
bipolar electrosurgical heating and typically employs high
frequency current whose frequency is at least 100 kilohertz and
often, but not limited to, a frequency of less than 6 megahertz.
Bipolar electrosurgical heating of tissue may be employed in
combination with a resistively heatable blade (e.g., operating at a
blade temperature of 250.degree. C. using one of the aforementioned
temperature feedback control mechanisms) or may be employed with a
cold surgical blade to effect all of the necessary heating of the
underlying tissue necessary to achieve the sealing of severed blood
vessels and associated hemostasis.
[0016] The disclosure, accordingly, comprises the apparatus,
system, and method possessing the construction, combination of
elements, arrangement of parts and steps, which are exemplified in
the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a fuller understanding of the nature and objects hereof,
reference should made to the following detailed description taken
in connection with the accompanying drawings.
[0018] FIG. 1 is an isometric representation of a hemostatic
surgical system;
[0019] FIG. 2 is an isometric view of the handpiece, shank, blade
support arms and blade for a first embodiment of the present
disclosure;
[0020] FIG. 3 is an exploded isometric view of the handpiece,
shank, blade support arms and blade for a first embodiment of the
present disclosure;
[0021] FIG. 4 is an exploded isometric view of the shank and blade
support arms for a first embodiment of the present disclosure;
[0022] FIG. 5 is an end view of the blade support arms for a first
embodiment of the present disclosure;
[0023] FIG. 6 is an isometric view of a subassembly comprising the
shank and support arms for a first embodiment of the present
disclosure;
[0024] FIG. 7 is a side view of a subassembly comprising the shank
and support arms for a first embodiment of the present
disclosure;
[0025] FIG. 8 is a top view of the thermal barrier member and its
carrier provided to facilitate assembly;
[0026] FIG. 9 is an isometric view of the thermal barrier member
and its carrier provided to facilitate assembly;
[0027] FIG. 10 is an enlarged top view of the thermal barrier
member as referenced in Detail A of FIG. 9;
[0028] FIG. 11 is an isometric view of the handpiece, shank, blade
support arms and blade for a second embodiment of the present
disclosure;
[0029] FIG. 12A is an exploded isometric view of the handpiece,
shank, blade support arms and blade for a second embodiment of the
present disclosure;
[0030] FIG. 12B is detailed side view of second thermally
conductive blade support arm;
[0031] FIG. 12C is isometric view of distal end of thermally
conductive blade support shank showing first and second thermally
conductive blade support arms;
[0032] FIG. 12D is top view of thermally conductive blade support
shank and first and second thermally conductive blade support
arms;
[0033] FIG. 12E is side view of thermally conductive blade support
shank and first and second thermally conductive blade support
arms;
[0034] FIG. 13 is an isometric view of the flexible circuit
component incorporated in a second embodiment of the present
disclosure;
[0035] FIG. 14 is an isometric view of a surgically sharp blade
with straight cutting edge;
[0036] FIG. 15 is a top view of a surgically sharp blade with
straight cutting edge;
[0037] FIG. 15A is a cross-sectional view of a surgically sharp
blade with straight cutting edge;
[0038] FIG. 16 is a top view of a surgically sharp blade with
straight cutting edge and electrical heater disposed thereon;
[0039] FIG. 17 is a top view of a surgically sharp blade with
triangular cutting edge and electrical heater disposed thereon;
[0040] FIG. 18 is a cross-sectional view of a surgically sharp
blade with triangular cutting edge and electrical heater disposed
thereon as referenced in FIG. 17 as Section X-X;
[0041] FIG. 19 is a cross-sectional view of a blade comprising an
electrically and thermally conductive blade, electrically
insulative layer disposed on blade, electrically resistive heater
disposed on the electrically insulative layer and non-stick coating
covering entire blade except for tip of cutting edge;
[0042] FIG. 20 is a cross-sectional view of a blade comprising an
electrically insulative and thermally conductive blade,
electrically resistive heater disposed on the electrically
insulative and thermally conductive blade and non-stick coating
covering entire blade except for tip of cutting edge;
[0043] FIG. 21 is a cross-sectional view of a blade comprising an
electrically resistive and thermally conductive blade and non-stick
coating covering entire blade except for tip of cutting edge;
[0044] FIG. 22 is a cross-sectional view of a blade comprising an
electrically resistive, ferromagnetic or ferrimagnetic layer
disposed on the surface of an non-ferromagnetic or
non-ferrimagnetic, electrically and thermally conductive blade with
an optional non-stick coating covering entire blade except for tip
of cutting edge;
[0045] FIG. 23 is top view of four-conductor flexible circuit lead
pattern for conducting current to contact pads and lead pattern for
measuring tissue impedance;
[0046] FIG. 24 is a detailed top view of proximal end of
four-conductor flexible circuit lead pattern for conducting current
to contact pads and lead pattern for measuring tissue
impedance;
[0047] FIG. 25 is a detailed top view of mid-length portion of
four-conductor flexible circuit at location in which power leads
and sense leads branch corresponding to first and second blade
support arms;
[0048] FIG. 26 is a detailed top view of distal end portion of
four-conductor flexible circuit at location in which electrical
contact pads for power lead and sense lead are positioned
corresponding to second blade support arm;
[0049] FIG. 27 is cross-section view of tissue and end view of
curette assembly illustrating current flux lines in tissue used to
measure electrical impedance of underlying tissue;
[0050] FIG. 28 is cross-sectional view of assembly comprising
blade, blade support arm, washers, insulating sleeve, heating
element, heater lead and sensor lead;
[0051] FIG. 29 is a detailed cross-sectional view of region in
which power lead electrical contact pad is in electrical
communication with electrical contact pad on heatable blade;
and
[0052] FIGS. 30A and 30B combine as labeled thereon to provide a
flow chart describing the operation and use of the apparatus and
system for the excision of soft tissue in humans using a
mechanically sharp, heatable blade of the present disclosure as
seen in FIGS. 1-29.
[0053] The drawings will be described in further detail below.
DETAILED DESCRIPTION
[0054] The present disclosure for the excision of soft tissue in
humans using a mechanically sharp, heated blade is seen in the
system shown in FIG. 1. As seen in FIG. 1, a system, 10, comprises
a controller, 12, a handpiece, 14, connected to controller 12 via a
handpiece cable, 36, a footpedal, 16, connected to controller 12
via a footpedal cable, 22. Still referring to FIG. 1, handpiece 14
comprises a handle, 34, a blade support member, 32, and a heatable
blade, 30. Handpiece cable 36 extending from handpiece 14 is
connected to controller 12 using a removably attachable handpiece
cable connector, 38. Footpedal 16 comprises a first pedal, 18, to
activate and control application of power to heatable blade 30
during tissue cutting at preselected set-point temperature, T1.
Footpedal 16 also comprises a second footpedal, 20, to activate and
control application of power to heatable blade 30 during optional
blood vessel sealing following tissue cutting at preselected
set-point temperature, T2. A footpedal cable, 22, extending from
footpedal 16 is connected to controller 12 using removably an
attachable footpedal cable connector, 24. As seen in FIG. 1,
controller 12 includes an on/off power switch, 39, a set-point
temperature decrease control switch, 41, a set-point temperature
increase control switch, 43, as well as a temperature set-point and
operating status as indicated on display screen, 45.
[0055] Referring now to FIGS. 2 and 3, handpiece 14 is illustrated
in greater detail. As seen in FIG. 2, handpiece 14 comprises a
handle, 34, a blade support member, 32, and a heatable blade, 30.
As seen in FIG. 3, a blade support member, 32, comprises two
electrically and thermally conductive blade support shanks, 50 and
52, and two electrically and thermally conductive blade support
arms, 51 and 53, respectively. Electrically and thermally
conductive blade support shank 50 and integral blade support arm 51
are electrically isolated from the electrically and thermally
conductive blade support shank 52 and integral blade support arm 53
by an electrically insulative spacer, 56. An exploded view of
handpiece 14 is seen in FIG. 3. Handle 34 comprises first and
second handle shell halves, 40a and 40b, that enclose the proximal
end of blade support member 32 and mechanically attached to one
another by first and second fastening screws, 42a and 42b, in
combination with first and second fastening nuts, 48a and 48b,
respectively. As seen in FIG. 3, the first and second fastening
screws 42a and 42b are electrically isolated from blade support
member 32 by first and second electrically insulative sleeve pairs,
44a, 46a and 44b, 46b.
[0056] Still referring to FIG. 3, blade support member is seen in
isometric view comprising first electrically and thermally
conductive blade support shank 50 and second electrically and
thermally conductive blade support shank 52 surrounding an
intervening electrically insulative spacer, 56, that electrically
isolates the first electrically and thermally conductive blade
support shank 50 from the second electrically and thermally
conductive blade support shank 52. First and second electrical lead
connectors, 80a and 80b, in electrical communication with first and
second electrical leads, 81a and 81b, respectively, are in
electrical communication with and fastened to first electrically
and thermally conductive blade support shank 50 and second
electrically and thermally conductive blade support shank 52,
respectively, using first and second electrical lead connector
fastening screws, 82a and 82b, respectively.
[0057] Still referring to FIG. 3, first electrically and thermally
conductive blade support arm 51 extends from first electrically and
thermally conductive blade support shank 50. In like manner, second
electrically and thermally conductive blade support arm 53 extends
from second electrically and thermally conductive blade support
shank 52. During an assembly step, heatable blade 30 is
mechanically fastened to first electrically and thermally
conductive blade support arm 51 and second electrically and
thermally conductive blade support arm 53 with intervening a
thermal barrier assembly, 60. The mechanical fastening is
accomplished with first and second fastening screws, 72a and 72b,
with electrically and thermally insulative sleeves, 76a and 76b,
surrounding exposed portion of fastening screws to electrically and
thermally isolate the fastening screws 72a and 72b from heatable
blade 30. In addition, electrically and thermally insulative
washers, 74a and 74b, are positioned between fastening screws 72a
and 72b and heatable blade 30 to electrically and thermally isolate
the fastening screws 72a and 72b from heatable blade 30. By way of
example, one-piece thermally conductive blade support arm 51 and
integral thermally conductive blade support shank 50, as well as
one-piece thermally conductive blade support arm 53 and integral
thermally conductive blade support shank 52, are preferably a high
copper content electrically and thermally conductive metal such as
Oxygen Free Hard Copper (OHFC) or other materials such as, for
example, high-strength aluminum alloys.
[0058] Turning now to FIG. 4, blade support member 32 is seen in an
exploded isometric view comprising first electrically and thermally
conductive blade support shank 50 and second electrically and
thermally conductive blade support shank 52 surrounding intervening
electrically insulative spacer 56. In a preferred embodiment, a
first adhesive layer, 54, is positioned between first electrically
and thermally conductive blade support shank 50 and intervening
electrically insulative spacer 56. Likewise, a second adhesive
layer, 58, is positioned between second electrically and thermally
conductive blade support shank 52 and intervening electrically
insulative spacer 56. In addition to adhesive bonding of a
subassembly comprising first electrically and thermally conductive
blade support shank 50, intervening electrically insulative spacer
56 and second electrically and thermally conductive blade support
shank 52, first and second fastening screws, 84a and 84b, are used
to mechanically attach and form the composite subassembly
comprising first electrically and thermally conductive blade
support shank 50, intervening electrically insulative spacer 56 and
second electrically and thermally conductive blade support shank
52. As seen in FIG. 4, electrically insulative washers, 86a and
86b, and electrically insulative sleeves, 88a and 88b, electrically
isolate fastening screws 84a and 84b, respectively, from
electrically and thermally conductive blade support shank 52.
[0059] The distal end of blade support member 32 is seen in
isometric view in FIG. 5 revealing fastening screw 84a and
electrically insulative washer 86a that mechanically fastens first
electrically and thermally conductive blade support shank 50 to
second electrically and thermally conductive blade support shank 52
on either surface of intervening electrically insulative spacer 56.
Isometric and side views of blade support member 32 are
additionally provided in FIGS. 6 and 7.
[0060] Turning now to FIGS. 8, 9 and 10, thermal barrier assembly
60, as well as first and second thermally and electrically
insulative spacers, 62a and 62b, are seen in greater detail. As
seen in FIG. 8, a thermal barrier assembly comprises thermal
barrier member carrier, 61, as well as first and second thermally
and electrically insulative spacers 62a and 62b. As seen in FIGS. 8
and 10, the first and second thermally and electrically insulative
spacers 62a and 62b are surmounted by first and second electrical
contact pads, 64a and 64b, and first and second electrically
conductive vias, 66a and 66b, respectively. The first and second
electrically conductive vias 66a and 66b provide electrical
communication with corresponding first and second electrical
contact pads on opposite face of electrically insulative spacers
62a and 62b (not shown). The first and second electrical contact
pads 64a and 64b are electrically connected to corresponding
electrical contact pads on heatable blade using high-temperature
electrically conductive adhesive, by way of example but not
limitation, an adhesive such as EPO-TEK H20E supplied by Epoxy
Technology, Inc., Billerica, Mass. (adhesive layer not shown).
Likewise, first and second electrical contact pads on opposite face
of electrically insulative spacers 62a and 62b (not shown) are
electrically connected to corresponding electrical contact surfaces
on first electrically and thermally conductive blade support arm 51
and second electrically and thermally conductive blade support arm
53, respectively. As seen in FIG. 8, first and second scored neck
regions, 63a and 63b, enable the thermal barrier member carrier 61
with attached first and second thermally insulative spacers 62a and
62b to be readily separated along the first and second score lines
63a and 63b, respectively, after the above specified electrically
conductive adhesive bonding process has been completed.
[0061] By way of example but not limitation and referring to FIG.
8, EPO-TEK H20E may be screen printed on the first and second
electrical contact pads 64a and 64b on the first surface of the
thermally insulative spacers 62a and 62b, respectively. Next, the
EPO-TEK H20E may be screen printed on the first and second
electrical contact pads on the second surface of the thermally
insulative spacers 62a and 62b (not shown) corresponding to and in
electrical communication with first and second electrical contact
pads 64a and 64b, respectively. Next and referring to FIGS. 3 and
8, the subassembly comprising the heatable blade 30 and thermal
barrier assembly 60, with screen printed electrically conductive
adhesive on both sides of first and second thermally insulative
spacers 62a and 62b, is mechanically fastened to first and second
electrically and thermally conductive blade support arms 51 and 53
using first and second fastening screws, 72a and 72b. Next the
mechanically fastened subassembly is placed in an air convention
oven for 15 minutes at a temperature of 120.degree. C. to cure the
adhesive and effect the electrically conductive bonds at [a] the
interfaces with contact pads, 164a and 164b, surmounted on heatable
blade 30 (as seen in FIG. 16) and the interfaces with the first and
second electrically and thermally conductive blade support arms 51
and 53. Finally, referring to FIGS. 2 and 8, the thermal barrier
member carrier 61 is separated from the first and second thermally
insulative spacers 62a and 62b to provide a subassembly comprising
[a] electrically conductive bonds between first and second
electrical contact pads 64a and 64b and contact pads 164a and 164b
surmounted on heatable blade 30 as well as [b] electrically
conductive bonds between first and second electrical contact pads
on the second surface of the thermally insulative spacers 62a and
62b (not shown) and electrically conductive surface of electrically
and thermally conductive blade support arms 51 and 53,
respectively, as seen in FIG. 2.
[0062] As seen in FIGS. 2 through 7, the first embodiment of the
present disclosure enables the conduction of heating current from
leads 81a and 81b to the heatable blade 30 via first and second
electrically and thermally conductive blade support shanks 50 and
52 and extending to the tip of first and second electrically and
thermally conductive blade support arms 51 and 53, respectively. As
seen in FIG. 4, electrically insulative spacer 56 assures
electrical isolation between first and second electrically and
thermally conductive blade support shanks 50 and 52. Still
referring to FIG. 4, adhesive bonds between first and second
electrically and thermally conductive blade support shanks 50 and
52 and interspaced electrically insulative spacer 56 is provided by
first and second double-sided adhesive layers 54 and 58. The
adhesive bonds results in a multi-layer cantilever beam sandwich
with improved stiffness to reduce deflection in the presence of
applied forces at the distal end of blade support member 32
associated with tissue excision, tamponade, and sealing of
transected blood vessels.
[0063] The exposed heads of first and second fastening screws 72a
and 72b are coated with an electrically insulative and
biocompatible coating to prevent electrical stimulation of in vivo
tissue, if electrical heating current frequency supplied to
heatable blade 30 is less than about 50 kHz. By way of example but
without limitation, the electrically insulative and biocompatible
coating may be an applied coating of Parylene C having a thickness
in the range from 0.0003 to 0.0020 inch having a thickness in the
range from 0.0003 to 0.0020 inch (Specialty Coating Systems, Inc.,
Indianapolis, Ind.). Also, the exposed surfaces of electrically and
thermally conductive blade support shank 50 and integral blade
support arm 51, as well as electrically and thermally conductive
blade support shank 52 and integral blade support arm 53, are
coated with an electrically insulative and biocompatible coating.
By way of example but without limitation, the electrically
insulative and biocompatible coating may be an applied coating of
Parylene C having a thickness in the range from 0.0003 to 0.0020
inch (Specialty Coating Systems, Inc., Indianapolis, Ind.).
[0064] In the design of the first embodiment of the present
disclosure, as seen in FIGS. 2 through 7, [a] the widths and
thicknesses of electrically and thermally conductive blade support
shanks 50 and 52 and first and second electrically and thermally
conductive blade support arms 51 and 53, [b] the width and
thickness of thermally insulative spacers 62a and 62b, [c] the
metal or alloy selected for use in the construction of thermally
conductive blade support shanks 50 and 52 and integral thermally
conductive blade support arms 51 and 53, [d] the material selected
for use in the construction of thermally insulative spacers 62a and
62b, [e] the thickness and material selected for first and second
electrically and thermally insulative washers 74a and 74b, [f] the
thickness and material selected for first and second electrically
and thermally insulative sleeves 76a and 76b and [g] the diameter
and material selected for first and second fastening screws 72a and
72b have all been selected to reduce the conduction of heat from
the heated blade 30 (e.g., operating at a temperature in the range
from about 150.degree. to 250.degree. C. during tissue excision and
sealing of blood vessels) to the first and second electrically and
thermally conductive blade support arms 51 and 53 so that the
maximum temperature of the exposed surfaces of the electrically and
thermally conductive blade support arms 51 and 53 do not exceed
about 50.degree. C. during an excision and coagulation procedure.
By maintaining the maximum temperature of the exposed surfaces of
the electrically and thermally conductive blade support arms 51 and
53 at or below about 50.degree. C. during the expected exposure
duration associated with an excision and coagulation procedure,
unwanted thermal injury to surrounding healthy tissue is avoided.
The preferred dimensions of thermally conductive blade support
shanks 50 and 52 and integral thermally conductive blade support
arms 51 and 53, as well as the thermally insulative spacers 62a and
62b, electrically and thermally insulative washers 74a and 74b, and
electrically and thermally insulative sleeves 76a and 76b are
provided in a subsequent section of this specification and
associated referenced drawings.
[0065] By way of example and referring to FIGS. 2 through 7,
electrically and thermally conductive blade support shanks 50 and
52 and integral electrically and thermally conductive blade support
arms 51 and 53 may be Oxygen Free Hard Copper or selected from
other high-copper content copper alloys or selected from
high-aluminum content aluminum alloys providing a thermal
conductivity of at least 1.5 watts/cm-C. Elongated electrically and
thermally conductive blade support shanks 50 and 52 may be
malleable to enable an operator to manually alter the shape of
elongated blade support shanks 50 and 52 to improve access to an
intended surgical site. Thermally insulative spacers 62a and 62b
may advantageously be constructed using polyimide material, such as
Polyimide Laminate 85N (e.g., available from Arlon Technologies,
Rancho Cucamonga, Calif.). Electrically and thermally insulative
washers 74a and 74b may advantageously be constructed using
polyimide material, such as Kapton (e.g., available from Boker's
Inc., Minneapolis, Minn.). Electrically and thermally insulative
sleeves 76a and 76b may advantageously be constructed using
polyimide material (e.g., available from MicroLumen, Inc., Oldsmar,
Fla.). Fastening screws 72a and 72b (e.g., screw size 80 or 90) may
advantageously be constructed using stainless steel Type 304 or
Type 316 (e.g., available from US Microscrew, Seattle, Wash.).
[0066] A second embodiment of the present disclosure is illustrated
in FIGS. 11 through 13. Unlike the first embodiment of the present
disclosure as seen in FIGS. 2 through 7 and described in the
preceding paragraphs, the conduction of heating current, as seen in
FIGS. 11 through 13, from leads 116a and 116b to heatable blade 30
is accomplished via first and second electrically conductive leads,
152 and 154, disposed on an electrically insulative flexible
substrate, 150, and extending to the tip of first and second
thermally conductive blade support arms 131a and 131b.
[0067] In the design of the second embodiment of the present
disclosure, as seen in FIGS. 11 through 13, [a] the widths and
thicknesses of thermally conductive blade support shanks, 104, and
first and second electrically and thermally conductive blade
support arms, 131a and 131b, [b] the width and thickness of the
thermally insulative spacers 62a and 62b, [c] the metal or alloy
selected for use in the construction of thermally conductive blade
support shank 104 and integral thermally conductive blade support
arms 131a and 131b, [d] the material selected for use in
construction of the thermally insulative spacers 62a and 62b, [e]
the thickness and material selected for first and second
electrically and thermally insulative washers 144a and 144b, [f]
the thickness and material selected for first and second
electrically and thermally insulative sleeves 146a and 146b and [g]
the diameter and material selected for first and second fastening
screws 142a and 142b have all been selected to reduce the
conduction of heat from the heated blade 30 (e.g., operating at a
temperature of 150.degree. to 250.degree. C. during tissue excision
and sealing of blood vessels) to first and second electrically and
thermally conductive blade support arms 131a and 131b, so that the
maximum temperature of the exposed surfaces of electrically and
thermally conductive blade support arms 131a and 131b do not exceed
about 50.degree. C. during an excision and coagulation procedure.
By maintaining the maximum temperature of the exposed surfaces of
electrically and thermally conductive blade support arms 131a and
131b at or below about 50.degree. C. during an excision and
coagulation procedure, unwanted thermal injury to surrounding
healthy tissue is avoided. The preferred dimensions of thermally
conductive blade support shank 104 and integral thermally
conductive blade support arms 131a and 131b, as well as the
thermally insulative spacers 62a, 62b, electrically and thermally
insulative washers 144a, 144b, electrically and thermally
insulative sleeves 146a, 146b, and fastening screws 142a, 142b are
provided in a subsequent section of this description and associated
referenced drawings.
[0068] By way of example and referring to FIGS. 11 through 13,
thermally conductive blade support shank 104 and integral thermally
conductive blade support arms 131a and 131b may be Oxygen Free Hard
Copper or selected from other high-copper content copper alloys or
selected from high-aluminum content aluminum alloys providing a
thermal conductivity of at least 1.5 watts/cm-C. Thermally
insulative spacers 62a and 62b may advantageously be constructed
using polyimide material, such as Polyimide Laminate 85N (e.g.,
available from Arlon Technologies, Rancho Cucamonga, Calif.).
Electrically and thermally insulative washers 144a and 144b may
advantageously be constructed using polyimide material, such as
Kapton (e.g., available from Boker's Inc., Minneapolis, Minn.).
Electrically and thermally insulative sleeves 146a and 146b may
advantageously be constructed using polyimide material (e.g.,
available from MicroLumen, Inc., Oldsmar, Fla.). Fastening screws
142a and 142b may advantageously be constructed using stainless
steel Type 304 or Type 315 (e.g., available from US Microscrew,
Seattle, Wash.). The exposed surfaces of thermally conductive blade
support shank 104 and integral blade support arms 131a and 131b are
coated with a biocompatible coating. By way of example but without
limitation, the biocompatible coating may be an applied coating of
Parylene C having a thickness in the range from 0.0003 to 0.0020
inch (Specialty Coating Systems, Inc., Indianapolis, Ind.).
[0069] As seen in FIG. 11, a handpiece comprises handle, 100,
thermally conductive blade support member, 110, first and second
thermally conductive blade support arms 131a and 131b and heatable
blade 30. Referring now to FIGS. 11 and 12A, handpiece 14 is shown
in greater detail. As seen in the exploded isometric view in FIG.
12A, handle 100 comprises first and second handle shell halves 102a
and 102b that enclose the proximal end of blade support member 110
and are mechanically attached to one another by first and second
fastening screws 112a and 112b in combination with first and second
fastening nuts 114a and 114b, respectively, with spacer plate 108
positioned against the second surface of thermally conductive blade
support shank. Still referring to FIG. 12A, blade support member
110 comprises thermally conductive blade support shank 104 that
extends distally to first and second thermally conductive blade
support arms 131a and 131b.
[0070] Referring now to FIGS. 12A and 13, a two-conductor flexible
circuit, 106, is surmounted on and adhesively attached (e.g., using
pressure sensitive adhesive such as 3M Cat. No. 9082 manufactured
by 3M Company, Minneapolis, Minn.) to thermally conductive blade
support shank 104 providing electrical communication between [a]
first and second electrical connectors 116a and 116b positioned at
proximal end of two-conductor flexible circuit 106 and [b] first
and second electrical contact pads 158a and 158b positioned at
distal end of two-conductor flexible circuit 106 via first and
second electrically conducting lead 152 and 154, respectively. By
way of example and without limitation and referring to FIG. 13,
two-conductor flexible circuit 106 may be fabricated by adhesively
bonding thin copper foil, having a thickness in the range from
0.0007 inch to 0.0028 inch, to flexible electrically insulative
polyimide substrate 150, such as Kapton (DuPont, Wilmington, Del.)
having a thickness in the range from 0.001 inch to 0.004 inch.
Photolithography is then used to selectively chemically etch and
remove certain portions of the adhesively bonded copper on a
flexible polyimide substrate to provide a preferred electrically
conductive lead pattern. As seen in FIG. 13, photolithography and
selective chemical etching is used to produce two-conductor
flexible circuit 106 comprising [a] first electrically conductive
lead trace 152 disposed on electrically insulative flexible
polyimide substrate 150 that extends from proximal end of
two-conductor flexible circuit 106 to [a] a first branching arm
lead trace, 153, and first electrical contact pad 158a and [b]
second electrically conductive lead trace 154 disposed on
electrically insulative flexible polyimide substrate 150 that
extends to a second branching arm lead trace, 155, and second
electrical contact pad 158b.
[0071] Returning to exploded view of handpiece 14 in FIG. 12A,
first and second electrical lead connectors 116a and 116b in
electrical communication with first and second electrical leads
115a and 115b, respectively, are in placed in electrical
communication with the proximal ends of first and second
electrically conducting leads 152 and 154, respectively. First and
second electrical lead connectors 116a and 116b are fastened to and
electrically insulated from thermally conductive blade support
shank 104 using first and second electrical lead connector
fastening screws 118a and 118b, respectively, in combination with
first and second electrically insulative sleeves, 117a, 117b, and
first and second fastening nuts, 119a, 119b, respectively.
[0072] Still referring to FIG. 12A, spacer plate 108 is positioned
between blade support member 104 and second handle shell half 102b
to provide increased stability of blade support member 104 in the
presence of applied forces at the distal end of blade support
member 104 at first and second thermally conductive blade support
arms 131a, 131b and supported heatable blade 30, the applied forces
associated with tissue excision, tamponade and sealing of
transected blood vessels.
[0073] By way of example and without limitation, still referring to
FIG. 12A, first and second thermally conductive blade support arms
131a and 131b extend from thermally conductive blade support shank
104. During an assembly step, heatable blade 30 is mechanically
fastened to first and second thermally conductive blade support
arms 131a and 131b with an intervening thermal barrier assembly,
130. The mechanical fastening is accomplished with first and second
fastening screws 142a and 142b with electrically and thermally
insulative sleeves 146a and 146b surrounding exposed portion of
fastening screws to electrically and thermally isolate the
fastening screws 142a and 142b from heatable blade 30. In addition,
electrically and thermally insulative washers 144a and 144b are
positioned between fastening screws 142a and 142b and heatable
blade 30 to electrically and thermally isolate the fastening screws
142a and 142b from heatable blade 30. Referring now to FIGS. 12A,
13, and 16, the mechanical assembly with electrically conductive
adhesive applied between first and second electrical contact pads
158a, 158b at the distal end of two-conductor flexible circuit 106
and corresponding first and second blade heater electrical contact
pads 164a, 164b is next placed in a convection oven (e.g., at
120.degree. C. for 15 minutes) to cure the electrically conductive
adhesive. The first and second electrical contact pads 158a and
158b are electrically connected to corresponding first and second
electrical contact pads 164a and 164b on heatable blade using
high-temperature electrically conductive adhesive, by way of
example but not limitation, an adhesive such as EPO-TEK H20E that
cures at 120.degree. C. for a 15 minute heating period (adhesive
layer not shown). The EPO-TEK H20E adhesive is supplied by Epoxy
Technology, Inc., Billerica, Mass.
[0074] Referring next to FIGS. 12B through 12E, alternative views
of thermally conductive blade support member 104 and integral first
and second thermally conductive blade support arms 131a and 131b
are provided with dimensional annotations that refer to the range
of preferred dimensions indicated in a subsequent section of this
specification.
[0075] Turning now to FIGS. 14 through 16, alternative views of
heatable blade 30, as incorporated in the first and second
embodiments of the tissue excision system of the present
disclosure, are provided including an isometric view of a first
surface, 185, of heatable blade 30 (as seen in FIG. 14), top view
of first surface 185 of heatable blade 30 (as seen in FIG. 15),
cross-sectional view of heatable blade 30 (as seen in FIG. 15A) and
top view of a planar second surface, 187, of heatable blade 30
surmounted by an electrically insulative layer, 160, an
electrically conductive heating element, 162, first and second
blade heater contact pads, 164a, 164b, (as seen in FIG. 16). As
seen in FIGS. 14, 15 and 15A, heatable blade 30 comprises first
surface 185 of a thermally conductive blade substrate, 170,
including a single-bevel region, 180, with included angle .phi.1, a
flat region, 186, first and second through holes, 182a, 182b. As
seen in FIGS. 15A and 16, heatable blade 30 comprises a planar
second surface, 187, of thermally conductive blade substrate 170.
As seen in FIGS. 14, 15 and 16, heatable blade 30 is configured
with a straight cutting edge, 189. As seen in FIGS. 14, 15 and 16,
indexing notches, 184a and 184b, may be included on perimeter of
thermally conductive blade substrate 170 opposite cutting edge 189
to facilitate registration of thermally conductive blade substrate
170 during thick film printing process.
[0076] Turning now to FIGS. 17 and 18, an alternative embodiment of
heatable blade 30 is seen wherein the heatable blade 30 is
configured with a triangular shaped blade, 181, having cutting
edges, 190a, 190b, disposed on either side of a triangular blade
apex, 194. As incorporated in the first and second embodiments of
the tissue excision system of the present disclosure, alternative
embodiment of heatable blade 30, as seen in FIG. 17, includes top
view of a planar second surface, 187, of heatable blade 30
surmounted by electrically insulative layer 160, electrically
conductive heating element 162, first and second blade heater
contact pads 164a, 164b. A cross-sectional view of alternative
embodiment of heatable blade 30 is seen in FIG. 18 comprising first
surface 185 of thermally conductive blade substrate 170 including
single-bevel region 180 with included angle .phi.1, flat region
186, first and second through holes 182a, 182b, and planar second
surface 187 surmounted by electrically insulative layer 160 and
electrically conductive heating element 162. Returning to FIG. 17,
heatable blade 30 is configured as a triangular shaped cutting
edge, 190, with included angle, .phi.2 to reduce the force required
for the incision of tissue due to the angle of the cutting edges,
190a, 190b, relative to cutting direction, 191.
[0077] Turning now to FIGS. 19 through 22, several different
embodiments are specified for the electrical heating of heatable
blade 30, as incorporated in the first and second embodiments of
the tissue excision system of the present disclosure. In the
cross-section view of heatable blade 30 seen in FIG. 19, second
surface 187 of thermally conductive blade substrate 170 is
surmounted first by electrically insulative layer 160 and then
electrically conductive heating element 162 is disposed on the
electrically insulative layer 160. The exterior surface of heatable
blade 30 is covered with a non-stick coating, 165, except at a
cutting edge tip region, 166, preferably exposing an uncoated
length of cutting edge tip region 166 ranging from 0.003 to 0.010
inch. Non-stick coating 165 minimizes adherence of tissue and
coagulum during tissue incision. In addition, non-stick coating
165, if selected with electrically insulative characteristics, to
electrically isolate heating element 162 from tissue contacted
during tissue incision. Alternatively, prior to the application of
non-stick coating 165, a second electrically insulative layer (not
shown) may be disposed over layer of heating element 162 using the
same electrically insulative material as used for electrically
insulative layer 160 to electrically isolate heating element 162
from tissue contacted during tissue incision. The heating current
induced within heating element 162 may range from direct current to
alternating current having a frequency of up to about one
megahertz, preferably in the range from at least 100 to 400
kilohertz to minimize the effects of nerve stimulation. The
temperature of the blade is preferably controlled by heater
resistance feedback control enabled by the high temperature
coefficient of resistance (TCR) of the conductive material
incorporated into the glass matrix of the electrically conductive
heating element 162 as described in U.S. Pat. No. 8,475,444,
incorporated herein by reference. By way of example and without
limitation, [a] thermally conductive blade substrate 170 may be
GIN-5 martensitic stainless steel heat treated to a hardness of at
least 58 Rockwell C (Hitachi Metals America, Ltd., Arlington
Heights, Ill.), [b] electrically insulative layer 160 may be a
screen-printable glass dielectric layer (ElectroScience
Laboratories, King of Prussia, Pa.) and electrically conductive
heating element 162 may be a silver-filled, screen-printable glass
layer (ElectroScience Laboratories, King of Prussia, Pa.).
Non-stick coating 165 may be a polytetrafluoroethylene coating
(Whitford Corporation, Elverson, Pa.). Other dimensions of the
blade and disposed layers comprising heatable blade 30, as seen in
FIG. 19, are designated as noted and are specified below.
[0078] In the cross-section view of heatable blade 30 seen in FIG.
20, second surface 187 of electrically insulative and thermally
conductive blade substrate 172 is surmounted by an electrically
conductive heating element, 168, disposed on surface of the
electrically insulative and thermally conductive blade substrate
172. The exterior surface of heatable blade 30 is covered with
non-stick coating 165 except at the cutting edge tip region 166,
preferably exposing an uncoated length of the cutting edge tip
region 166 ranging from 0.003 to 0.010 inch. Non-stick coating 165
minimizes adherence of tissue and coagulum during tissue incision.
In addition, non-stick coating 165, if selected with electrically
insulative characteristics, to electrically isolate heating element
162 from tissue contacted during tissue incision. Alternatively,
prior to the application of non-stick coating 165, an electrically
insulative layer (not shown) may be disposed over layer of heating
element 162 using the same electrically insulative material as used
for electrically insulative layer 160 (as seen in FIG. 19) to
electrically isolate heating element 162 from tissue contacted
during tissue incision. The heating current induced within heating
element 168 may range from direct current to alternating current
having a frequency of up to about one megahertz, preferably in the
range from at least 100 to 400 kilohertz to minimize the effects of
nerve stimulation. The temperature of the blade is preferably
controlled by heater resistance feedback control enabled by the
high temperature coefficient of resistance (TCR) of the conductive
material incorporated into the electrically conductive heating
element 162 wherein the temperature coefficient of resistance is at
least 400 parts-per-million (ppm) per degree C. By way of example,
electrically conductive heating element 162 may be a glass matrix
of a high temperature coefficient of resistance (TCR) conductor as
described in U.S. Pat. No. 8,475,444 and incorporated herein by
reference. By way of example and without limitation, [a]
electrically insulative and thermally conductive blade substrate
172 may be Aluminum Nitride (Ceradyne, Inc., Costa Mesa, Calif.)
and electrically conductive heating element 168 may be a
silver-filled, screen-printable glass layer (ElectroScience
Laboratories, King of Prussia, Pa.). Non-stick coating 165 may be a
polytetrafluoroethylene coating (Whitford Corporation, Elverson,
Pa.). Other dimensions of the blade and disposed layers comprising
heatable blade 30, as seen in FIG. 20, are designated as noted and
are specified below.
[0079] In the cross-section view of heatable blade 30 seen in FIG.
21, electrically resistive and thermally conductive blade substrate
174 functions as both the cutting edge and the electrical heater.
In this embodiment, referring momentarily to FIG. 15 as well as
referring to FIG. 21, electrical current flows through the length,
L2 of heatable blade. The exterior surface of heatable blade 30 is
covered with non-stick coating 165 except at the cutting edge tip
region 166, preferably exposing an uncoated length of the cutting
edge tip region 166 ranging from 0.003 to 0.010 inch. The heating
current induced within heating element 168 may range from direct
current to alternating current having a frequency of up to about
one megahertz, preferably in the range from at least 100 to 400
kilohertz to minimize the effects of nerve stimulation. The
temperature of the blade is preferably controlled by temperature
feedback control (temperature sensor not shown). By way of example
and without limitation, electrically resistive and thermally
conductive blade substrate may be silicon carbide. In this
alternative embodiment, a temperature sensor is positioned in
thermal communication with heatable blade 30 to measure, regulate
and maintain the temperature of heatable blade 30 within a narrow
range around a pre-selected set-point temperature. By way of
example and without limitation, a Chromel-Alumel thermocouple may
be attached to heatable blade 30 using high-temperature, thermally
conductive adhesive (e.g., EPO-TEK H20E supplied by Epoxy
Technology, Inc., Billerica, Mass.) to enable temperature feedback
control to maintain the temperature of heatable blade 30 at
250.degree. C..+-.10.degree. C. during the intended tissue incision
and optional post-incision application of heat to effect further
hemostasis within transected blood vessels. Other dimensions of the
blade and disposed layers comprising heatable blade 30, as seen in
FIG. 21, are designated as noted and are specified below.
[0080] In the cross-section view of heatable blade 30 seen in FIG.
22, the perimeter of electrically and thermally conductive,
non-ferromagnetic or non-ferrimagnetic blade substrate, 176, is
coated with a ferromagnetic or ferrimagnetic material, 178.
Alternatively, ferromagnetic or ferrimagnetic material 178 may
extend around the entire perimeter of electrically and thermally
conductive, non-ferromagnetic or non-ferrimagnetic blade substrate
176 except at the cutting edge tip region 166, preferably exposing
an uncoated length of the cutting edge tip region 166 ranging from
0.003 to 0.010 inch. Following the coating of the perimeter of
electrically and thermally conductive, non-ferromagnetic or
non-ferrimagnetic blade substrate 176 with the ferromagnetic or
ferrimagnetic material 178, the exterior surface of heatable blade
30 may be covered with non-stick coating 165 for blade operating
temperatures less than about 400.degree. C. except at cutting edge
tip region 166, preferably exposing an uncoated length of cutting
edge tip region 166 ranging from 0.003 to 0.010 inch. For
ferromagnetic or ferrimagnetic or ferrite materials selected to
operate at a blade temperature of greater than about 400.degree.
C., preferably greater than 450.degree. C., a non stick coating is
not necessary since tissue and blood coagulum adherence does not
occur at blade surface temperatures above 400.degree. C. By way of
example, the coating of ferromagnetic or ferrimagnetic material 178
may be applied using vapor deposition, sputtering deposition,
thermal plasma spraying, or plating process. By way of example and
without limitation, thermally conductive, non-ferromagnetic or
non-ferrimagnetic blade substrate 176 may be GIN-5 martensitic
stainless steel heat treated to a hardness of at least 58 Rockwell
C (Hitachi Metals America, Ltd., Arlington Heights, Ill.).
Ferromagnetic or ferrimagnetic coating 178 may be formed from [a]
an alloy containing iron and nickel, by way of example but without
limitation, Permalloy (ESPI Metals, Ashland, Oreg.) and Moly
Permalloy (Hamilton Precision Metals, Lancaster, Pa.) or [b] other
ferromagnetic or ferrimagnetic coatings containing at least one of
the following constituents: Co, Fe, Ni, FeOFe.sub.2O.sub.3,
NiOFe.sub.2O.sub.3, CuO Fe.sub.2O.sub.3, MgOFe.sub.2O.sub.3, MnBi,
MnSb, MnOFe.sub.2O.sub.3, Y3Fe5012, Gd, EuO, magnetite, yttrium
iron garnet, manganese, and aluminum. Non-stick coating 165 may be
a polytetrafluoroethylene coating (Whitford Corporation, Elverson,
Pa.). Other dimensions of the blade and disposed layers comprising
heatable blade 30, as seen in FIG. 20, are designated as noted and
are specified below. The Curie temperature of ferromagnetic or
ferrimagnetic coating 178 may advantageously be selected to
correspond to the pre-selected temperature of heatable blade 30
during tissue incision (by way of example, a Curie temperature in
the range from 150.degree. to 600.degree. C.). Regulation of the
temperature of heatable blade 30 is achieved by the fact that
current flow is no longer confined to the layer comprising
ferromagnetic or ferrimagnetic coating 178, thereby effecting Curie
temperature autoregulation of the temperature of heatable blade 30.
In regard to Curie temperature autoregulation of heating elements,
refer to U.S. Pat. No. 4,256,945, which is incorporated herein by
reference. Other dimensions of the blade and disposed layers
comprising heatable blade 30, as seen in FIG. 22, are designated as
noted and are specified below. The heating current induced within
ferromagnetic or ferrimagnetic coating 178 is commonly a constant
(average) electrical current level whose frequency ranges from
about 4 megahertz to 24 gigahertz to induce skin effect heating
wherein the current flow is predominantly confined to the surface
or "skin" layer of a conductor.
[0081] Still referring to FIG. 22, ferromagnetic or ferrimagnetic
coating 178 may be selected so that heatable blade 30 is maintained
at a pre-selected elevated temperature (e.g., 150.degree. C. to
30.degree. 0 C) that is below the Curie temperature of
ferromagnetic or ferrimagnetic coating 178. In this alternative
embodiment, a temperature sensor is positioned in thermal
communication with heatable blade 30 to measure, regulate, and
maintain the temperature of heatable blade 30 within a narrow range
around a pre-selected set-point temperature. By way of example and
without limitation, a Chromel-Alumel thermocouple may be attached
to heatable blade 30 using high-temperature, thermally conductive
adhesive (e.g., EPO-TEK H20E supplied by Epoxy Technology, Inc.,
Billerica, Mass.) to enable temperature feedback control to
maintain the temperature of heatable blade 30 at 250.degree.
C..+-.10.degree. C. during the intended tissue incision and
optional post-incision application of heat to effect further
hemostasis within transected blood vessels. The heating current
induced within ferromagnetic or ferrimagnetic coating 178 is a
variable electrical current level to effect temperature feedback
control. In this embodiment, the frequency ranges from about 4
megahertz to 24 gigahertz to induce skin-effect heating wherein the
current flow is predominantly confined to the surface or "skin"
layer represented by ferromagnetic or ferrimagnetic coating 178 in
FIG. 22.
[0082] A third embodiment of the present disclosure, as seen in
FIGS. 23 through 29, for the excision of tissue with a mechanically
sharp, heatable blade 30 is similar to the second embodiment of the
present disclosure as seen in FIGS. 11 through 13 except that a
four-conductor flexible circuit, 230, replaces the two-conductor
flexible circuit 106 seen in FIG. 13. Four-conductor flexible
circuit 230 comprises, first and second power leads, 196a and 196b,
as well as first and second sense leads, 198a and 198b (as seen in
FIGS. 23, 24 and 25), that extend from first and second contact
pads, 209a and 209b, respectively (as seen in FIG. 24), to first
and second contact rings, 202a and 202b, respectively (as seen in
FIG. 26), located at the distal end of support arms 131a and 131b,
respectively (as seen in FIG. 27). Sense leads 198a, 198b (as seen
in FIGS. 24 and 25) enable the application of an applied voltage
between the exposed surfaces of first and second electrically
conductive fastening screws 238a, 238b (as seen in FIG. 27) to
determine the electrical impedance of soft tissue, 224, overlying
osseous layer, 226, based on the magnitude of the measured
electrical current flow between the first and second electrically
conductive fastening screws 238a, 238b, as represented by current
flux lines, 228 (as seen in FIG. 27).
[0083] Returning to FIG. 23, a top-view of the four-conductor
flexible circuit 230 is seen with three regions designated Detail
A, B, and C shown in greater detail in FIGS. 24, 25 and 26,
respectively. Turning now to FIG. 24, the proximal end of the
four-conductor flexible circuit 230 and designated as Detail A
comprises first and second power leads 196a and 196b terminating at
first and second power lead contact pads, 207a and 207b,
respectively, incorporating first and second through holes, 206a
and 206b, respectively, to accommodate passage of first and second
power lead fastening screws (not shown), respectively. Still
referring to FIG. 24, the proximal end of the four-conductor
flexible circuit 230 and designated as Detail A also comprises
first and second sense leads 198a and 198b terminating at first and
second sense lead contact pads, 209a and 209b, respectively,
incorporating first and second through holes, 208a and 208b,
respectively, to accommodate passage of first and second power lead
fastening screws (not shown), respectively.
[0084] Turning now to FIG. 25, the forward end of four-conductor
flexible circuit 230 and designated Detail B comprises [a] first
and second power leads 196a and 196b, [b] first and second sense
leads 198a and 198b extending to [c] first and second branches of
four-conductor flexible circuit, 236a and 236b, respectively. As
seen in Detail C presented in FIG. 26, the second arm of distal end
of four-conductor flexible circuit 230 corresponding to second
thermally conductive support arm 131b comprises a second through
hole, 193b, and a fourth through hole, 204b, at distal end of a
second electrically insulative flexible extension tab substrate,
210b.
[0085] Turning now to FIGS. 27 and 28, the electrical communication
between [a] the first and second power leads 196a, 196b and the
heatable blade 30 and [b] the first and second sense leads 198a,
198b and the first and second electrically conductive fastening
screws, 238a, 238b, is shown in greater detail. As seen in FIG. 27,
an end view of blade support member 110 comprises first and to
second thermally conductive support arms 131a and 131b (also seen
in FIGS. 12B through 12E), heatable blade 30, first and second
electrically and thermally insulative spacers 62a and 62b, first
and second electrically conductive fastening screws 238a and 238b,
first and second thermally and electrically insulative washers 144a
and 144b, first and second electrically insulative washers 214a and
214b and first and second mechanical fastening nuts 220a and 220b
threaded onto first and second electrically conductive fastening
screws 238a and 238b.
[0086] Referring now to FIGS. 26 and 27, first and second
electrically insulative flexible extension tab substrates 210a and
210b are seen to extend from [a] distal end of four-conductor
flexible circuit 230 emerging at interface between heatable blade
30 and the second electrically and thermally insulative spacers 62a
and 62b to [b] interface between first and second electrically
insulative washers 214a and 214b and first and second mechanical
fastening nuts 220a and 220b. The first and second electrically
insulative flexible extension tab substrates 210a and 210b enable
first and second contact rings 202a and 202b located at distal end
of first and second sense leads 198a and 198b (as seen in FIG. 26)
to be in electrical communication with first and second
electrically conductive fastening screws 238a and 238b. The heads
of the first and second electrically conductive fastening screws
238a and 238b enable electrical communication with soft tissue 224
through direct electrical contact with soft tissue 224 as seen in
FIG. 27, thereby enabling the measurement of electrical impedance
of soft tissue 224 located between first and second electrically
conductive fastening screws 238a and 238b. The higher the level of
measured electrical impedance of soft tissue 224 located between
first and second electrically conductive fastening screws 238a and
238b, the greater degree of desiccation of soft tissue 224 and the
correspondingly greater degree of hemostasis within transected
blood vessels.
[0087] By way of example and without limitation, a detailed
cross-sectional view of distal end of first thermally conductive
blade support arm 131a is seen in FIGS. 28 and 29 comprising, in
sequence, first electrically conductive fastening screw 238a, first
thermally and electrically insulative washer 144a, electrically and
thermally insulative sleeve 146a, thermally conductive blade
substrate 170, electrically insulative layer 160, first blade
heater contact pad 164a, first electrically conductive adhesive
layer 216a, first distal power lead electrical contact pad 195a,
first support arm flexible circuit substrate 212a, first thermally
insulative spacer 62a, distal end of first thermally conductive
blade support arm 131a, first and electrically insulative washer
214a, distal end of first electrically insulative flexible
extension tab substrate 200a, first distal sense lead electrical
contact pad 202a disposed on distal end of first electrically
insulative flexible extension tab substrate 200a and first
mechanical fastening nut 220a threaded onto first electrically
conductive fastening screw 238a. Referring to both symmetrical
branches seen, in part, in FIGS. 26 and 27, electrical
communication between the first and second distal sense lead
electrical contact pads, 202a, 202b, and sense leads, 198a, 198b,
is provided by first and second sense lead extensions, 199a, 199b,
disposed on first and second electrically insulative extension
tabs, 210a, 210b, respectively (wherein first distal sense lead
electrical contact pads 202a, sense lead 198a, first sense lead
extensions 199a and first electrically insulative extension tabs
210a not shown since only the second branch of four-conductor
flexible circuit 236b in seen in FIG. 26).
[0088] By way of example and without limitation and referring to
FIGS. 23 through 29, four-conductor flexible circuit 230 comprising
first and second power leads 196a and 196b, first and second power
lead contact pads 207a and 207b, first and second distal power lead
electrical contact pads 195a and 195b, first and second sense leads
198a and 198b, first and second sense lead contact pads 209a and
209b, first and second distal sense lead electrical contact pads
202a and 202b may be fabricated by adhesively bonding thin copper
foil, having a thickness in the range from 0.0007 inch to 0.0028
inch, to a flexible electrically insulative polyimide substrate 150
such as Kapton (DuPont, Wilmington, Del.) having a thickness in the
range from 0.001 inch to 0.004 inch. Photolithography is then used
to selectively chemically etch and remove certain portions of the
adhesively bonded copper on a flexible polyimide substrate to
provide a preferred electrically conductive lead pattern as seen in
FIGS. 23 through 29. Based on a copper lead thickness of 0.0014
inch, the widths of each of first and second power leads 196a and
196b in the first and second branches of the four-conductor
flexible circuit preferably range from 0.045 to 0.055 as seen in
FIG. 25. Based on a copper lead thickness of 0.0014 inch, the
widths of each of first and second sense leads 198a and 198b in
first and second branches of the four-conductor flexible circuit
236a and 236b preferably range from 0.010 to 0.015 as seen in FIG.
25. As seen in FIG. 29, electrically conductive adhesive layer 216a
may be a high-temperature electrically conductive adhesive, by way
of example but not limitation, an adhesive such as EPO-TEK H20E
supplied by Epoxy Technology, Inc., Billerica, Mass.
[0089] Yet another embodiment of the present disclosure is seen
wherein the first and second electrically conductive fastening
screws 238a and 238b enable electrical communication with soft
tissue 224 through direct electrical contact with soft tissue 224
as seen in FIG. 27, thereby enabling [a] the measurement of
electrical impedance of soft tissue 224 located between first and
second electrically conductive fastening screws 238a and 238b, such
as to identify when maximum tissue impedance has been achieved (the
screws act as electrodes) and/or [b] the conduction of high
frequency current through soft tissue 224 to effect resistive
heating of the underlying tissue. This method of tissue heating by
the passage of high frequency current directly through tissue is
commonly known as bipolar electrosurgical heating and typically
employs a high-frequency current whose frequency is at least 100
kilohertz and often, but not limited to, a frequency of less than 6
megahertz. In regard to bipolar heating of tissue, refer to U.S.
Pat. No. 5,891,142, which is incorporated herein by reference.
Bipolar electrosurgical heating of soft tissue 224, as described
above, may be employed in combination with a heatable blade 30
employing one of the heating element designs seen in FIGS. 19-22
(e.g., operating at a nominal blade temperature of 250.degree. C.
using one of the aforementioned temperature feedback control
mechanisms) or may be employed with a cold surgical blade to effect
all of the necessary heating of the underlying tissue necessary to
achieve the sealing of severed blood vessels and associated
hemostasis.
[0090] The range of dimensions for components of tissue excision
system 10, as seen in FIGS. 4, 5, 7, 9, 11, 12B, 12C, 12D, 12E, 15,
16, 17, 18, 19, 20, 21, 22, and 27 are summarized below in units of
inches unless specified otherwise:
L1=0.08 to 0.35
L2=0.35 to 1.60
L3=0.01 to 0.05
L4=0.10 to 0.35
L5=5.6 to 14.0
L6=2.5 to 6.0
L7=0.30 to 0.85
L8=0.30 to 0.85
W1=0.03 to 0.15
W2=0.10 to 0.30
W3=0.15 to 0.35
W4=0.30 to 0.60
W5=0.30 to 1.50
W6=0.30 to 0.60
W7=0.20 to 0.60
W8=0.10 to 0.35
W9=0.03 to 0.15
W10=0.04 to 0.16
[0091] t1=0.02 to 0.10 t2=0.0002 to 0.005 t3=0.0001 to 0.005
t4=0.02 to 0.10 t5=0.0001 to 0.005 t6=0.02 to 0.10 t7=0.02 to 0.10
t8=0.0001 to 0.010 t9=0.0002 to 0.003 t10=0.04 to 0.15 t11=0.04 to
0.15 t12=0.04 to 0.15 t13=0.02 to 0.10 t14=0.03 to 0.30
T1=70 to 600 C
T2=70 to 600 C
[0092] N1=0.5 to 5.0 seconds .phi.1=15 to 35 degrees .phi.2=35 to
60 degrees
[0093] The method for incising soft tissue while minimizing
bleeding utilizing the preferred embodiments of the present
disclosure is disclosed in connection with FIGS. 1 through 29 is
set forth in the flow chart represented in FIGS. 30A and 30B. Those
figures should be considered as labeled thereon. Looking first to
FIGS. 1 and 30A, the surgical procedure commences as described at
block 240 and arrow 242. A first step requires that controller 12
be turned to "ON" position using on/off power switch 39 and, using
set-point temperature increase and decrease control switches 43,
41, and screen display 45, select set-point temperature, T1, for
incision of soft tissue or, alternatively, using pre-determined
default set point temperature (e.g., 250.degree. C.) as described
at block 244 and arrow 246. Next, removably attachable connector 38
located at proximal end of handpiece cable 36 is connected to first
receptacle 37 on front panel of controller 12, as described at
block 248 and arrow 250. Next, removably attachable connector 24
located at proximal end of footpedal cable 22 is connected to
second receptacle 23 on front panel of controller 12, as described
at block 252 and arrow 254.
[0094] Still referring to FIGS. 1 and 30A, controller 12 then
automatically initiates pre-programmed self-test of operating
system, as well as self-test of electrical connections to handpiece
14 and footpedal 16, as described at block 256 and arrow 258.
Controller 12 then determines if electrical connections to
handpiece 14 and footpedal 16 are confirmed, as described at block
260. If electrical connections between handpiece 14 and/or
footpedal 16 and controller 12 are not confirmed, then a connection
fault for the handpiece 14 and/or footpedal 16 is indicated on
display screen 45 of controller 12 requiring operator to repeat
steps for attaching removably attachable connector at proximal end
of handpiece cable 38 and/or removably attachable connector at
proximal end of footpedal cable 24 to first and second receptacles
37 and 23, respectively, at front panel of controller 12 as
described at arrow 276, block 278 and arrow 277. However, if
electrical connections between handpiece 14 and/or footpedal 16 and
controller 12 are confirmed, then controller 12 initiates
pre-programmed test of electrical resistance of heater disposed on
heatable blade 30, as described at arrow 262, block 264 and arrow
266. If electrical resistance of heater disposed on heatable blade
30 is not within pre-determined electrical resistance range, then a
heater resistance fault is indicated on display screen 45, as well
as directive to replace faulty handpiece 14, as described at arrow
280, block 282 and arrow 284. However, if electrical resistance of
heater disposed on heatable blade 30 is within pre-determined
electrical resistance range, then controller 12 indicates "Position
Heatable Cutting Blade in Preparation for Tissue Incision" on
display screen 45 as described at block 272 and arrow 274.
[0095] Referring next to FIGS. 1 and 30B, operator depresses first
pedal 18 of footpedal 16 labeled "Cut" and waits for a period of
several seconds until audible intermittent tone issued by
controller 12 becomes a continuous audible tone indicating that
heatable blade 30 has reached selected or default "Cut"
temperature, T1, as described at block 286 and arrow 288. Operator
then positions heatable blade 30 at surgical site and proceeds to
initiate and complete intended incision of soft tissue with
heatable blade 30 at distal end of handpiece 14 while continuing to
depress first pedal 18 of footpedal 16 and operator releases first
pedal 18 of footpedal 16 to suspend power application to heatable
blade 30, as described at block 290 and arrow 292. Advantageously,
referring momentarily to FIGS. 2 and 16, the operator may
manipulate handle 34 to orient the angle of straight cutting edge
189 relative to the direction of cutting 191 at an angle of between
about 15 and 30 degrees relative to the direction of the forward
direction to reduce the force required for soft tissue excision.
Operator next visually examines site of completed tissue incision
to observe whether there is any residual bleeding occurring from
transected blood vessels, as described at block 294. If there is no
visually observable bleeding from transected blood vessels at site
of completed tissue excision, then surgical procedure is complete
and handpiece 14 is removed from surgical site, as described at
arrow 298 and block 300.
[0096] Referring to FIGS. 1 and 30B, if there is visually
observable bleeding from transected blood vessels at site of
completed tissue excision, then operator depresses second pedal 20
labeled "Coag" of footpedal 16 and waits for a period of several
seconds until audible intermittent tone issued by controller 12
becomes a continuous audible tone indicating that heatable blade 30
has reached selected or default "Coag" temperature, T2, as
described at arrow 296, block 302 and arrow 304.
[0097] Referring now to FIGS. 1, 27 and 30B, operator determines if
controller 12 and handpiece 14 include capability to measure
electrical impedance of soft tissue 224 in region underlying plane
of incision as seen in FIG. 27, as described at block 310. If
controller 12 and handpiece 14 do include capability to measure
electrical impedance of soft tissue 224 in region underlying plane
of incision, as seen in FIG. 27, then operator positions heatable
blade 30 at site of visually observable bleeding from transected
blood vessels and proceeds to apply tamponade with distal face of
heatable blade 30 to tissue (as seen at arrow 312 and block 307)
and simultaneously listens for decrease in frequency of audible
tone and attainment of a continuous lower frequency audible tone
issued by controller 12 during period while simultaneously applying
heat to soft tissue 224 using heatable blade 30 operating at "Coag"
temperature, T2, to seal any blood vessels not previously sealed
during the soft tissue incision step, as described at arrow 313 and
block 318. If frequency of audible tone issued by controller 12
detected by operator continues to decrease, the operator continues
to depress second pedal 20 labeled "Coag" of footpedal 16, as
described at arrow 322, block 324 and returning via arrow 326 to
block 318. If frequency of audible tone issued by controller 12
detected by operator is no longer continuing to decrease, but is
audibly constant, the operator releases second pedal 20 labeled
"Coag" of footpedal 16 and removes heatable blade 30 from tissue
incision site since surgical procedure is complete, as described at
arrow 320 and block 328.
[0098] Still referring now to FIGS. 1, 27 and 30B, if controller 12
and handpiece 14 does not include capability to measure electrical
impedance of soft tissue 224 in region underlying plane of incision
(as seen in FIG. 27), then operator positions heatable blade 30 at
site of visually observable bleeding from transected blood vessels
and proceeds to apply tamponade with distal face of heatable blade
30 to soft tissue 224 while simultaneously applying heat to tissue
for a period of N1 seconds to seal any blood vessels not previously
sealed during the soft tissue incision step followed by the release
of second footpedal 20 by operator to suspend power application to
heatable blade 30, as described at arrow 308 and block 306. At the
end of heat and tamponade application duration of N1 seconds,
surgical procedure is complete, as described at arrow 314 and block
316.
[0099] While the apparatus, system, and method have been described
with reference to various embodiments, those skilled in the art
will understand that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope and essence of the disclosure. In addition, many
modifications may be made to adapt a particular situation or
material in accordance with the teachings of the disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the disclosure not be limited to the particular
embodiments disclosed, but that the disclosure will include all
embodiments falling within the scope of the appended claims. In
this application all units are in the US engineering system, unless
otherwise expressly indicated. Also, all citations referred herein
are expressly incorporated herein by reference.
* * * * *