CA1161326A - Abherent surgical instrument and method - Google Patents
Abherent surgical instrument and methodInfo
- Publication number
- CA1161326A CA1161326A CA000357735A CA357735A CA1161326A CA 1161326 A CA1161326 A CA 1161326A CA 000357735 A CA000357735 A CA 000357735A CA 357735 A CA357735 A CA 357735A CA 1161326 A CA1161326 A CA 1161326A
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- Prior art keywords
- tissue
- cut
- surgical apparatus
- abherent
- abherent coating
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/08—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by means of electrically-heated probes
- A61B18/082—Probes or electrodes therefor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/08—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by means of electrically-heated probes
- A61B18/082—Probes or electrodes therefor
- A61B18/085—Forceps, scissors
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00053—Mechanical features of the instrument of device
- A61B2018/00107—Coatings on the energy applicator
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00964—Features of probes
- A61B2018/0097—Cleaning probe surfaces
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- Health & Medical Sciences (AREA)
- Surgery (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biomedical Technology (AREA)
- Molecular Biology (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Plasma & Fusion (AREA)
- Physics & Mathematics (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Otolaryngology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Surgical Instruments (AREA)
- Materials For Medical Uses (AREA)
Abstract
ABHERENT SURGICAL INSTRUMENT AND METHOD
Abstract of the Disclosure Method and means are disclosed for preventing tissue from adhering to surgical apparatus while operating at tissue temperatures at which hemostasis with minimal tissue damage occurs, and include interposing between the surgical apparatus and the tissue being heated thereby an abherent coating which is specifically limited to parameters including thermal impedance, thickness and thermal drop thereacross.
Abstract of the Disclosure Method and means are disclosed for preventing tissue from adhering to surgical apparatus while operating at tissue temperatures at which hemostasis with minimal tissue damage occurs, and include interposing between the surgical apparatus and the tissue being heated thereby an abherent coating which is specifically limited to parameters including thermal impedance, thickness and thermal drop thereacross.
Description
l 161326 ABHERENT SURG~ CAL INSTRUMENT AND ME~HOD
Background of the Invention Surgical devices which heat the tissue to provide hemostasis are described in the literature (seP, for example, U. S. Patents RE 29,088, 4,091,813 and 4,18~,632). The ad-herence of tissue to such surgical devices severely limits their usefulness because the resulting avulsion of tissue causes un-desirable tissue damage and bleeding. Also, the adherence of tissue to such surgical devices limits the surgeon's control of the device, and the build-up of adherent tissue material causes apparent dullness of the device. Additionallyl the build-up of adherent tissue materlal on heater-type surgical devices intro-duces a high thermal impedance between the heater and the tissue being cut that prevents heating of the tissues to the desired temperature. These problems of tissue adhering to the surgical device are especially severe for tissue temperatures within the range from about 100C. to about 500C.
Summary of the Invention Applicant has discovered that the tissue temperature for the optimum condition of hemostasis with minimal tissue damage varies with the type of tissue being cut and may be as low as about 130C. (on the soft palate of the mouth) and as high as about 450C. to 500C. (on highly vascularized tissue), above which tissue adherence usually does not occur. In accordance with the present invention, the optimum conditions of hemostasis with minimal tissue damage can be attained by operating at tissue temperatures in the range from about 100C. to about 500C. and by introducing between the surgical device and the contacted tissue an abherent coating having specific thermal parameters.
More particularly, in surgical apparatus which operates at elevated temperatures for heating the tissue contacted there-by, the heat transfer from the apparatus to the tissue in regions of the apparatus in contact with tissues may be twenty times greater than the heat transfer from the apparatus to the air in regions of the apparatus that are not in contact with tissue.
The heat transfer conditions vary widely as a function of the type of tissue being cut, the desired operating temperature, and the speed at which the device is moved through tissue.
To obtain optimum conditions of hemostasis with minimal tissue damage, the surgical device should rapidly elevate the temperature of the tissue to a preselected narrow range (usually between 100C. and 500C.) and should maintain the tissue temper-ature wlthin that range as cutting proceeds.
~ ny accumulation of tissue on that portion of the surgical device that contacts tissue can interpose a thermal impedance between the device and the tissues which may inhibit heat transfer and cause the temperature o the contacted tissue to drop below the value at which the optimum conditions of hemostasis with minimal tissue damage occur. Therefore, according to the present invention, an abherent coating is provided on the tissue-contacting surface of the surgical device which has thermal properties and characteristics within specific limits to assure that the temperature of tissue remains within the optimum range for which hemostasis and minimal tissue damage occur.
l 161326 Various asDects of the invention are as follows:
Surgical apparatus for rapidly cutting tissue and simultaneously heating such tissue in abherent contact therewith to an elevated temperature to provide hemostasis with minimal tissue damage, the apparatus com~rising:
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and .10 operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrlcally-insulating abherent coatlng means disposed intermediate the heating means and the tissue being cut to electrically lnsulate the surgical apparatus from the tissue being cut.
The method of preventing surgical apparatus which has a tissue-cutting edge to permit rapid movement through tissue from adhering to the tissue being cut thereby while simultaneously heating such tissue to an elevated temperature at which hemostasis with minimal tissue damage occurs, the method comprising the steps of:
heating the surgical apparatus during the rapid movement thereof through tissue being cut thereby;
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulati~g abherent coating for electrically isolating the surgical apparatus from the tissue being cut.
l 16132~
Figure 3 is a cross-sectional view of another embodiment of the present invention in which a heated surgical hemostat includes an abherent coating;
Figure 4 is a cross-sectional view of another embodiment of the present invention in which a sintered porous blade struc-ture with interconnecting passages provides a reservoir of abherent material;
Figure 5 is a detailed cross-sectional view of an embodiment of the present invention which illustrates the abherent coating on the surgical instrument disposed adjacent to the tissue being cut; and Figure 6 is a graph which illustrates the parameters of an abherent coating according to the present invention.
Detailed Description of the Preferred Embodiments Referring now to Figure 1, there i6 shown a surgical scalpel having a blade portion 11 with a cutting edge lO and an attached handle portion 8 which also carries a conductor of heating power from source 9 to the blade 11 to heat the same, as taught in the prior art. As shown in Figure 2, the surfaces of the blade ll, at least near the cutting edge 10, operate at elevated temperatures and contact tissue 13 via an abherent coating 12 interposed between the blade ll and tissue 13. This eliminates the problem of tissue 13 sticking to the surfaces of blade 11 ~ut introduces a thermal impedance between the heated blade 11 and the tissue 13 in contact therewith.
It has been determined that for portions of the blade 11 in contact with tissue, the heat flux 14 normal to or through the abherent coati.ng 12 is approximately 10 to 20 times greater than the heat flux therethrough to the air for portions of the blade 11 not in contact with tissue. This produces temperature l 161326 differences across the abherent coating 12. Thus, while the bla~e 11 is out of contact with tissue 13, the effective surface temperature of abherent coating 12 is approximately the same as the temperature of the blade 11. However, when the blade 11 and abherent coating 12 contact the tissue 13, the heat flux 14 passing through the thermal impedance presented by abherent coating 12 causes the surface temperature of ab-herent coating 12 to decrease below the desired temperature at which the optimum condition of hemostasis and minimal tissue damage occur. The temperature of the surface of abherent coating 12 may be increased to the desired temperature by in-creasing the temperature of the blade 11 by an amount sufficient to overcome the thermal drop across the abherent coating 12.
However, because of the transient conditions associated with the blade 11 bein~ in and out of contact with tissue 13 during a surgical procedure, the surface temperature of the abherent coating 12 may rise excessively while out of contact with tissue to cause deterioration of the abherent coating 12 and undesirable tissue damage upon recontact with tissue 13, as well as falling excessively when coming into contact with tissues to temperatures that are not hemostatic.
In contrast to these transient operating conditions in surgery, conventional cookware with abherent coatings do not in-volve transient operation. The heat transfer rate to an item being cooked is generally constant and is established without regard for damage to living tissue. Cookware also can be operated at higher temperatures to overcome the effects of high thermal impedance associated with thicker abherent coatings.
However, for reasons stated above, surgical devices cannot be arbitrarily set at a temperature significantly higher than the l 161326 optimum temperature at which hemostasis with minimal tissue damage occurs. Also, the thicknesses of coatin9s typically used on cookware cannot be used on surgical devices because of the blunting effect and degradation of the cutting action of a blade that would result.
In accordance with the present invention, the abherent coating 12 may be formed as a solid layer or as a sacrificial solid layer or as a sacrificial liquid layer. A solid abherent layer 12 may be formed on the device 11 including materials such as fluorocarbon polymers (exemplified by the fluorinated ethylene-propylene copolymers, polytetrafluoroethylene and polyethylene terephthalatet, or silicones and polydimethylsiloxanes with act~ve end groups, for example, of hydroxyl, amine, epoxide or thiol attached to the silicone polymer via a nonhydrolyzable Si-C bond, or fluoride-metal composites such as fluoride impreg-nated composites, or organic phosphates. Alternatively, a sacrificial solid abherent coating may be formed using materials such as silicone greases or hydrocarbon, synthetic and natural ester waxes, or sulfide compounds. In addition, a sacrificial solid abherent coating may be formed using fluorinated ethylene-propylene copolymers which have been found to be effective in that a coating thus formed "sloughs off n in thin platelets with use to provide the desired abherent characteristics with respect to tissue~
With respect to Figure 4, a sacrificial liquid abherent coating may be provided by forming a sintered or porous blade structure 11 with substantially continuous passages therethrough which can be impregnated with a material such as ~ilicone oil, for example, of the type based on dimethyl silicone, or ethers such as perfluoropoly-synthetic fluids. The porous and l 161326 impregnated structure according to Figure 4 thus establishes and maintains a continuous film of abherent material 12 at the surface of the device 11 which is disposed to contact tissue 13.
In accordance with the present invention, the thermal impedance of the abherent coating must be sufficientl~ low to permit transfer of heat 14 from the device 11 to the tissue 13 in contact therewith as illustrated in Figure 5. In particular, the tolerable thermal impedance of an abherent coating 12 depends generally upon the level of heat flux required for a particular surgical application. For example, in ophthalmic, neurological and plastic, and dermatological surgery procedures, hemostasis can be accomplished while cutting using heat fluxes well below 50 watts/cm . However, surgical procedures involving incisions in highly vascular tissues or rapid movement through tissue may require heat fluxes above S0 watts/cm to achieve hemostasis while cutting.
As used herein, "thermal impedance" is defined as follows:
R = hT
(Q/A) where R refers to the thermal impedance of the abherent coating 0 in units of C- cm , QT refers to the temperature difference watt across the abherent coating from the interface of the device 11/
abherent coating 12 to the outer surface of the abherent coating 12, in units of C., and Q/A refers to the heat flux flowing normal to or through the abherent coating, in units of watts/cm2.
Referring to Figure 5, the maximum allowed temperature difference ~T across the abherent coating under maximum heat flux conditions should not substantially exceed about 50C. in order to optimize hemostasis while minimizing tissue damage and 29 avoiding exposure of the surgical device and the abherent coating 1 16132~
to damaging temperatures. This tolerable temperature difference thus establishes the thermal impedance for the heat flux levels that will be encountered during use of the surgical device. The thermal impedances, as defined above, for abherent coatings 12 operating at specified levels of heat flux are summariæed below:
Heat Flux, Q/AMaximum Allowed Thermal Impedance, R, (watts/cm2)for Temperature Difference, ~T, of 50C.
_ 5.0
Background of the Invention Surgical devices which heat the tissue to provide hemostasis are described in the literature (seP, for example, U. S. Patents RE 29,088, 4,091,813 and 4,18~,632). The ad-herence of tissue to such surgical devices severely limits their usefulness because the resulting avulsion of tissue causes un-desirable tissue damage and bleeding. Also, the adherence of tissue to such surgical devices limits the surgeon's control of the device, and the build-up of adherent tissue material causes apparent dullness of the device. Additionallyl the build-up of adherent tissue materlal on heater-type surgical devices intro-duces a high thermal impedance between the heater and the tissue being cut that prevents heating of the tissues to the desired temperature. These problems of tissue adhering to the surgical device are especially severe for tissue temperatures within the range from about 100C. to about 500C.
Summary of the Invention Applicant has discovered that the tissue temperature for the optimum condition of hemostasis with minimal tissue damage varies with the type of tissue being cut and may be as low as about 130C. (on the soft palate of the mouth) and as high as about 450C. to 500C. (on highly vascularized tissue), above which tissue adherence usually does not occur. In accordance with the present invention, the optimum conditions of hemostasis with minimal tissue damage can be attained by operating at tissue temperatures in the range from about 100C. to about 500C. and by introducing between the surgical device and the contacted tissue an abherent coating having specific thermal parameters.
More particularly, in surgical apparatus which operates at elevated temperatures for heating the tissue contacted there-by, the heat transfer from the apparatus to the tissue in regions of the apparatus in contact with tissues may be twenty times greater than the heat transfer from the apparatus to the air in regions of the apparatus that are not in contact with tissue.
The heat transfer conditions vary widely as a function of the type of tissue being cut, the desired operating temperature, and the speed at which the device is moved through tissue.
To obtain optimum conditions of hemostasis with minimal tissue damage, the surgical device should rapidly elevate the temperature of the tissue to a preselected narrow range (usually between 100C. and 500C.) and should maintain the tissue temper-ature wlthin that range as cutting proceeds.
~ ny accumulation of tissue on that portion of the surgical device that contacts tissue can interpose a thermal impedance between the device and the tissues which may inhibit heat transfer and cause the temperature o the contacted tissue to drop below the value at which the optimum conditions of hemostasis with minimal tissue damage occur. Therefore, according to the present invention, an abherent coating is provided on the tissue-contacting surface of the surgical device which has thermal properties and characteristics within specific limits to assure that the temperature of tissue remains within the optimum range for which hemostasis and minimal tissue damage occur.
l 161326 Various asDects of the invention are as follows:
Surgical apparatus for rapidly cutting tissue and simultaneously heating such tissue in abherent contact therewith to an elevated temperature to provide hemostasis with minimal tissue damage, the apparatus com~rising:
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and .10 operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrlcally-insulating abherent coatlng means disposed intermediate the heating means and the tissue being cut to electrically lnsulate the surgical apparatus from the tissue being cut.
The method of preventing surgical apparatus which has a tissue-cutting edge to permit rapid movement through tissue from adhering to the tissue being cut thereby while simultaneously heating such tissue to an elevated temperature at which hemostasis with minimal tissue damage occurs, the method comprising the steps of:
heating the surgical apparatus during the rapid movement thereof through tissue being cut thereby;
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulati~g abherent coating for electrically isolating the surgical apparatus from the tissue being cut.
l 16132~
Figure 3 is a cross-sectional view of another embodiment of the present invention in which a heated surgical hemostat includes an abherent coating;
Figure 4 is a cross-sectional view of another embodiment of the present invention in which a sintered porous blade struc-ture with interconnecting passages provides a reservoir of abherent material;
Figure 5 is a detailed cross-sectional view of an embodiment of the present invention which illustrates the abherent coating on the surgical instrument disposed adjacent to the tissue being cut; and Figure 6 is a graph which illustrates the parameters of an abherent coating according to the present invention.
Detailed Description of the Preferred Embodiments Referring now to Figure 1, there i6 shown a surgical scalpel having a blade portion 11 with a cutting edge lO and an attached handle portion 8 which also carries a conductor of heating power from source 9 to the blade 11 to heat the same, as taught in the prior art. As shown in Figure 2, the surfaces of the blade ll, at least near the cutting edge 10, operate at elevated temperatures and contact tissue 13 via an abherent coating 12 interposed between the blade ll and tissue 13. This eliminates the problem of tissue 13 sticking to the surfaces of blade 11 ~ut introduces a thermal impedance between the heated blade 11 and the tissue 13 in contact therewith.
It has been determined that for portions of the blade 11 in contact with tissue, the heat flux 14 normal to or through the abherent coati.ng 12 is approximately 10 to 20 times greater than the heat flux therethrough to the air for portions of the blade 11 not in contact with tissue. This produces temperature l 161326 differences across the abherent coating 12. Thus, while the bla~e 11 is out of contact with tissue 13, the effective surface temperature of abherent coating 12 is approximately the same as the temperature of the blade 11. However, when the blade 11 and abherent coating 12 contact the tissue 13, the heat flux 14 passing through the thermal impedance presented by abherent coating 12 causes the surface temperature of ab-herent coating 12 to decrease below the desired temperature at which the optimum condition of hemostasis and minimal tissue damage occur. The temperature of the surface of abherent coating 12 may be increased to the desired temperature by in-creasing the temperature of the blade 11 by an amount sufficient to overcome the thermal drop across the abherent coating 12.
However, because of the transient conditions associated with the blade 11 bein~ in and out of contact with tissue 13 during a surgical procedure, the surface temperature of the abherent coating 12 may rise excessively while out of contact with tissue to cause deterioration of the abherent coating 12 and undesirable tissue damage upon recontact with tissue 13, as well as falling excessively when coming into contact with tissues to temperatures that are not hemostatic.
In contrast to these transient operating conditions in surgery, conventional cookware with abherent coatings do not in-volve transient operation. The heat transfer rate to an item being cooked is generally constant and is established without regard for damage to living tissue. Cookware also can be operated at higher temperatures to overcome the effects of high thermal impedance associated with thicker abherent coatings.
However, for reasons stated above, surgical devices cannot be arbitrarily set at a temperature significantly higher than the l 161326 optimum temperature at which hemostasis with minimal tissue damage occurs. Also, the thicknesses of coatin9s typically used on cookware cannot be used on surgical devices because of the blunting effect and degradation of the cutting action of a blade that would result.
In accordance with the present invention, the abherent coating 12 may be formed as a solid layer or as a sacrificial solid layer or as a sacrificial liquid layer. A solid abherent layer 12 may be formed on the device 11 including materials such as fluorocarbon polymers (exemplified by the fluorinated ethylene-propylene copolymers, polytetrafluoroethylene and polyethylene terephthalatet, or silicones and polydimethylsiloxanes with act~ve end groups, for example, of hydroxyl, amine, epoxide or thiol attached to the silicone polymer via a nonhydrolyzable Si-C bond, or fluoride-metal composites such as fluoride impreg-nated composites, or organic phosphates. Alternatively, a sacrificial solid abherent coating may be formed using materials such as silicone greases or hydrocarbon, synthetic and natural ester waxes, or sulfide compounds. In addition, a sacrificial solid abherent coating may be formed using fluorinated ethylene-propylene copolymers which have been found to be effective in that a coating thus formed "sloughs off n in thin platelets with use to provide the desired abherent characteristics with respect to tissue~
With respect to Figure 4, a sacrificial liquid abherent coating may be provided by forming a sintered or porous blade structure 11 with substantially continuous passages therethrough which can be impregnated with a material such as ~ilicone oil, for example, of the type based on dimethyl silicone, or ethers such as perfluoropoly-synthetic fluids. The porous and l 161326 impregnated structure according to Figure 4 thus establishes and maintains a continuous film of abherent material 12 at the surface of the device 11 which is disposed to contact tissue 13.
In accordance with the present invention, the thermal impedance of the abherent coating must be sufficientl~ low to permit transfer of heat 14 from the device 11 to the tissue 13 in contact therewith as illustrated in Figure 5. In particular, the tolerable thermal impedance of an abherent coating 12 depends generally upon the level of heat flux required for a particular surgical application. For example, in ophthalmic, neurological and plastic, and dermatological surgery procedures, hemostasis can be accomplished while cutting using heat fluxes well below 50 watts/cm . However, surgical procedures involving incisions in highly vascular tissues or rapid movement through tissue may require heat fluxes above S0 watts/cm to achieve hemostasis while cutting.
As used herein, "thermal impedance" is defined as follows:
R = hT
(Q/A) where R refers to the thermal impedance of the abherent coating 0 in units of C- cm , QT refers to the temperature difference watt across the abherent coating from the interface of the device 11/
abherent coating 12 to the outer surface of the abherent coating 12, in units of C., and Q/A refers to the heat flux flowing normal to or through the abherent coating, in units of watts/cm2.
Referring to Figure 5, the maximum allowed temperature difference ~T across the abherent coating under maximum heat flux conditions should not substantially exceed about 50C. in order to optimize hemostasis while minimizing tissue damage and 29 avoiding exposure of the surgical device and the abherent coating 1 16132~
to damaging temperatures. This tolerable temperature difference thus establishes the thermal impedance for the heat flux levels that will be encountered during use of the surgical device. The thermal impedances, as defined above, for abherent coatings 12 operating at specified levels of heat flux are summariæed below:
Heat Flux, Q/AMaximum Allowed Thermal Impedance, R, (watts/cm2)for Temperature Difference, ~T, of 50C.
_ 5.0
2.5 1.7 1~3 1.0 100 0,5 These values of thermal impedance for the abherent coating can establish the rnaximum allowed thickness for various abherent coatings. Referring to Figure 5, the allowed thickness of ab-herent coating 12 in a direction normal to the heat flux 14 is given by the relationship:
t = R-k where t refers to the maximum allowed abherent coating thickness in units of centimeters, R is the thermal impedance, as defined previously, and k refers to effective thermal conductivity of abherent coating 12 in units of watts/cmC.
The graph of Figure 6 illustrates the relationship between maximum thickness 18 of the abherent coating 12 and heat flux levels corresponding to high (100 watts/cm maximum) and low ~30 watts/cm maximum) heat flux requirements associated with various surgical procedures. By way of examp~e, certain fluoro-carbon materials that have been found efective as abherent coatings exhibit a thermal conductivity of about .0025 watts/cmC.
In accordance with the above, the thickness of an abherent coating of this material should not be greater than .0013 cm (0.5 mil) for operation at high heat flux levels.
In the apparatus of Figure 3, a pinch-type instrument 15 (such as a hemostat) may be heated in conventional manner by a source of heating power connected thereto to transfer heat 14 to tissue 16 via the abherent coating 12 interposed therebetween.
The maximum allowed thickness of abherent coating 12 is determined, as discussed above, with respect to the thermal impedance of the coating material and the operating level of heat flux involved.
t = R-k where t refers to the maximum allowed abherent coating thickness in units of centimeters, R is the thermal impedance, as defined previously, and k refers to effective thermal conductivity of abherent coating 12 in units of watts/cmC.
The graph of Figure 6 illustrates the relationship between maximum thickness 18 of the abherent coating 12 and heat flux levels corresponding to high (100 watts/cm maximum) and low ~30 watts/cm maximum) heat flux requirements associated with various surgical procedures. By way of examp~e, certain fluoro-carbon materials that have been found efective as abherent coatings exhibit a thermal conductivity of about .0025 watts/cmC.
In accordance with the above, the thickness of an abherent coating of this material should not be greater than .0013 cm (0.5 mil) for operation at high heat flux levels.
In the apparatus of Figure 3, a pinch-type instrument 15 (such as a hemostat) may be heated in conventional manner by a source of heating power connected thereto to transfer heat 14 to tissue 16 via the abherent coating 12 interposed therebetween.
The maximum allowed thickness of abherent coating 12 is determined, as discussed above, with respect to the thermal impedance of the coating material and the operating level of heat flux involved.
Claims (20)
1. Surgical apparatus for rapidly cutting tissue and simultaneously heating such tissue in abherent contact therewith to an elevated temperature to provide hemostasis with minimal tissue damage, the apparatus comprising:
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrically-insulating abherent coating means disposed intermediate the heating means and the tissue being cut to electrically insulate the surgical apparatus from the tissue being cut.
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrically-insulating abherent coating means disposed intermediate the heating means and the tissue being cut to electrically insulate the surgical apparatus from the tissue being cut.
2. Surgical apparatus according to claim 1 wherein said abherent coating means has a thickness that is not substantially greater than .0025 cm.
3. Surgical apparatus according to claim 1 wherein said abherent coating means has a maximum allowed thickness, t, in centimeters as given by the relationship:
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
4. Surgical apparatus according to claim 1 wherein the abherent coating means includes a composition selected from the group consisting of fluorocarbon polymers and silicone polymers.
5. Surgical apparatus according to claim 1 wherein said heating means is heated to elevated temperatures in response to applied electrical signal conducted there-through; and said abherent coating means is disposed to electrically insulate the heating means from the tissue being cut.
6. The method of preventing surgical apparatus which has a tissue-cutting edge to permit rapid movement through tissue from adhering to the tissue being cut thereby while simultaneously heating such tissue to an elevated temperature at which hemostasis with minimal tissue damage occurs, the method comprising the steps of:
heating the surgical apparatus during the rapid movement thereof through tissue being cut thereby;
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulating abherent coating for electrically isolating the surgical apparatus from the tissue being cut.
heating the surgical apparatus during the rapid movement thereof through tissue being cut thereby;
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulating abherent coating for electrically isolating the surgical apparatus from the tissue being cut.
7. The method according to claim 6 wherein in the step of interposing, an abherent coating is interposed between the tissue being cut and the surgical apparatus having a thickness which is not substantially greater than .0025 cm.
8. The method according to claim 6 wherein in the step of interposing, an abherent coating is interposed between the tissue being cut and the surgical apparatus having a maximum allowed thickness, t, in centimeters as given by the relationship:
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
9. The method according to claim 6 wherein the step of heating includes dissipating power in relation to the magnitude of applied electrical signal; and in the step of interposing, the abherent coating electrically isolates the applied electrical signals from tissue being cut.
10. Surgical apparatus for rapidly cutting tissue and simultaneously heating such tissue in abherent contact therewith to an elevated temperature to provide hemostasis with minimal tissue damage, the apparatus comprising:
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrically-insulating abherent coating means disposed intermediate the heating means and the tissue being cut to electrically insulate the surgical apparatus from the tissue being cut, said abherent coating means having a thermal drop thereacross while in contact with the tissue being cut that is not substantially greater than 50°C. for tissue temperatures within the range from about 100°C to about 500°C.
blade means having a tissue-cutting edge for rapidly severing tissue as the blade means moves therethrough;
heating means disposed on the blade means and operable to heat the tissue-cutting edge to an elevated temperature for heating the tissue being cut thereby;
and electrically-insulating abherent coating means disposed intermediate the heating means and the tissue being cut to electrically insulate the surgical apparatus from the tissue being cut, said abherent coating means having a thermal drop thereacross while in contact with the tissue being cut that is not substantially greater than 50°C. for tissue temperatures within the range from about 100°C to about 500°C.
11. The method of preventing adherence of surgical apparatus to tissue at an elevated temperature at which hemostasis with minimal tissue damage occurs, the method comprising the steps of:
heating the surgical apparatus during rapid movement thereof through tissue being cut thereby:
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulating abherent coating for electrically isolating the surgical apparatus from the tissue being cut, said abherent coating having a thermal drop thereacross while in contact with the tissue being cut that is not substantially greater than 50°C. for tissue temperatures within the range from about 100°C. to about 500°C.
heating the surgical apparatus during rapid movement thereof through tissue being cut thereby:
transferring heat to the tissue being cut from the surgical apparatus; and interposing between the tissue being cut and the surgical apparatus an electrically-insulating abherent coating for electrically isolating the surgical apparatus from the tissue being cut, said abherent coating having a thermal drop thereacross while in contact with the tissue being cut that is not substantially greater than 50°C. for tissue temperatures within the range from about 100°C. to about 500°C.
12. Surgical apparatus according to claim 10 wherein said abherent coating means has a thickness that is not substantially greater than .0025 cm.
13. Surgical apparatus according to claim 10 wherein said abherent coating means has a maximum allowed thickness, t, in centimeters as given by the relationship:
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
14. Surgical apparatus according to claim 10 wherein the abherent coating means includes a composition selected from the group consisting of fluorocarbon polymers and silicone polymers.
15. Surgical apparatus according to claim 10 wherein said heating means is heated to elevated temperatures in response to applied electrical signal conducted there-through; and said abherent coating means is disposed to electrically insulate the heating means from the tissue being cut.
16. The method according to claim 11 wherein in the step of interposing, an abherent coating is interposed between the tissue being cut and the surgical apparatus having a thickness which is not substantially greater than .0025 cm.
17. The method according to claim 11 wherein in the step of interposing, an abherent coating is interposed between the tissue being cut and the surgical apparatus having a maximum allowed thickness, t, in centimeters as given by the relationship:
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
where k is thermal conductivity of the abherent coating in watts/cm°C., and Q/A is the heat flux in watts/cm2.
18. The method according to claim 11 wherein the step of heating includes dissipating power in relation to the magnitude of applied electrical signal; and in the step of interposing, the abherent coating electrically isolates the applied electrical signals from tissue being cut.
19. Surgical apparatus as in claim 1 wherein said abherent coating means has a thermal impedance that is not substantially greater than 5 .
20. The method according to claim 6 wherein in the step of interposing, the interposed abherent coating has a thermal impedance that is not substantially greater than 5 .
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US7392779A | 1979-09-10 | 1979-09-10 | |
| US073,927 | 1979-09-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1161326A true CA1161326A (en) | 1984-01-31 |
Family
ID=22116637
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000357735A Expired CA1161326A (en) | 1979-09-10 | 1980-08-06 | Abherent surgical instrument and method |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5645648A (en) |
| AU (1) | AU6166380A (en) |
| BR (1) | BR8005831A (en) |
| CA (1) | CA1161326A (en) |
| DE (1) | DE3031049A1 (en) |
| FR (1) | FR2469174A1 (en) |
| GB (1) | GB2060397B (en) |
| NL (1) | NL8004670A (en) |
| SE (1) | SE449431B (en) |
| ZA (1) | ZA804849B (en) |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4481057A (en) * | 1980-10-28 | 1984-11-06 | Oximetrix, Inc. | Cutting device and method of manufacture |
| US4501951A (en) * | 1982-08-16 | 1985-02-26 | E. I. Du Pont De Nemours And Company | Electric heating element for sterilely cutting and welding together thermoplastic tubes |
| HU187227B (en) * | 1983-03-28 | 1985-11-28 | Laszlo Forintos | Surgical instrument particularly for nerve-surgical operations |
| US4534347A (en) * | 1983-04-08 | 1985-08-13 | Research Corporation | Microwave coagulating scalpel |
| JPS6065093A (en) * | 1983-09-21 | 1985-04-13 | Res Assoc Petroleum Alternat Dev<Rapad> | Treatment of oil sand oil and residual oil |
| WO1985002002A1 (en) * | 1983-11-01 | 1985-05-09 | Gardner Bros. & Perrott (W.A.) Pty. Ltd. | Descaling process |
| GB2158722B (en) * | 1983-12-01 | 1986-09-10 | Kh Nii Obschei Neotlozh Khirug | Electrosurgical instrument |
| DE3390553C2 (en) * | 1983-12-01 | 1988-05-26 | Char Kovskij Ni Skij I Obscej | Bipolar electrosurgical tool |
| GB2161081B (en) * | 1983-12-21 | 1987-02-25 | Kh Nii Obschei Neotlozh Khirur | Bipolar electrocoagulator |
| US4580558A (en) * | 1984-03-28 | 1986-04-08 | Codman & Shurtleff, Inc. | Laser instrument |
| US4682596A (en) * | 1984-05-22 | 1987-07-28 | Cordis Corporation | Electrosurgical catheter and method for vascular applications |
| USRE33925E (en) * | 1984-05-22 | 1992-05-12 | Cordis Corporation | Electrosurgical catheter aned method for vascular applications |
| GB2184021A (en) * | 1985-12-13 | 1987-06-17 | Micra Ltd | Laser treatment apparatus for port wine stains |
| FR2594322A1 (en) * | 1986-02-17 | 1987-08-21 | Cleef Jean Francois Van | Composite needle for single-pole electrocoagulation |
| US4886582A (en) * | 1988-06-29 | 1989-12-12 | Union Oil Company Of California | Resid hydroprocessing catalyst and method of preparation |
| JPH0375053A (en) * | 1989-08-18 | 1991-03-29 | Muranaka Iryoki Kk | Bipolar electrically solidifying tweezers |
| US5324289A (en) * | 1991-06-07 | 1994-06-28 | Hemostatic Surgery Corporation | Hemostatic bi-polar electrosurgical cutting apparatus and methods of use |
| US5348552A (en) * | 1991-08-30 | 1994-09-20 | Hoya Corporation | Laser surgical unit |
| WO1994009714A1 (en) * | 1992-11-04 | 1994-05-11 | Charles Edward Taylor | Electrically operated heating tool |
| US5713895A (en) * | 1994-12-30 | 1998-02-03 | Valleylab Inc | Partially coated electrodes |
| US5702387A (en) * | 1995-09-27 | 1997-12-30 | Valleylab Inc | Coated electrosurgical electrode |
| WO2001008570A1 (en) * | 1999-07-30 | 2001-02-08 | Drukker International Bv | A cutting blade for a surgical instrument |
| JP4502565B2 (en) | 2000-02-28 | 2010-07-14 | コンメド コーポレイション | Electrosurgical scalpel with silicon coating directly bonded |
| US7223266B2 (en) | 2003-02-04 | 2007-05-29 | Cardiodex Ltd. | Methods and apparatus for hemostasis following arterial catheterization |
| EP2182875A4 (en) | 2007-08-15 | 2011-08-24 | Cardiodex Ltd | Systems and methods for puncture closure |
| CN102805663A (en) * | 2012-07-06 | 2012-12-05 | 华中科技大学同济医学院附属同济医院 | Surgical instrument with mechanical cutting and hemostasis functions |
| US11191586B2 (en) * | 2019-07-02 | 2021-12-07 | Jamison Alexander | Removable tip for use with electrosurgical devices |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5063994U (en) * | 1973-10-09 | 1975-06-10 | ||
| BR7601564A (en) * | 1975-03-14 | 1976-09-14 | R Shaw | INSTRUMENT AND PROCESS FOR PERFORMING SURGICAL CUTS |
| US4091813A (en) * | 1975-03-14 | 1978-05-30 | Robert F. Shaw | Surgical instrument having self-regulated electrical proximity heating of its cutting edge and method of using the same |
| JPS539031A (en) * | 1976-07-13 | 1978-01-27 | Takenaka Komuten Co | Continuous sedimentation disposal equipment for highhmoisture sludge |
-
1980
- 1980-08-06 CA CA000357735A patent/CA1161326A/en not_active Expired
- 1980-08-08 ZA ZA00804849A patent/ZA804849B/en unknown
- 1980-08-16 DE DE19803031049 patent/DE3031049A1/en not_active Withdrawn
- 1980-08-19 NL NL8004670A patent/NL8004670A/en not_active Application Discontinuation
- 1980-08-22 AU AU61663/80A patent/AU6166380A/en not_active Abandoned
- 1980-08-29 GB GB8028064A patent/GB2060397B/en not_active Expired
- 1980-09-08 FR FR8019347A patent/FR2469174A1/en active Granted
- 1980-09-09 SE SE8006253A patent/SE449431B/en not_active IP Right Cessation
- 1980-09-09 JP JP12523780A patent/JPS5645648A/en active Granted
- 1980-09-10 BR BR8005831A patent/BR8005831A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE3031049A1 (en) | 1981-04-02 |
| FR2469174B3 (en) | 1982-04-23 |
| JPS5645648A (en) | 1981-04-25 |
| AU6166380A (en) | 1981-03-19 |
| GB2060397B (en) | 1984-06-20 |
| BR8005831A (en) | 1981-03-24 |
| SE449431B (en) | 1987-05-04 |
| ZA804849B (en) | 1981-08-26 |
| JPH0334939B2 (en) | 1991-05-24 |
| GB2060397A (en) | 1981-05-07 |
| NL8004670A (en) | 1981-03-12 |
| FR2469174A1 (en) | 1981-05-22 |
| SE8006253L (en) | 1981-03-11 |
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