Apparatus and method for cauterizing tissue

Abstract

Apparatus for cauterizing tissue comprising a probe mounted to a handle; a heating element configured to emit heat so as to heat a distal end region of said probe; a temperature sensor configured to emit a temperature signal reflecting the instantaneous temperature of said distal end region; an electronics module comprising: a controller and an amplifying transistor; wherein said controller is configured to selectively cycle said amplifying transistor between an ON condition and an OFF condition and such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; and wherein said controller is configured to use said temperature signal to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition.

Description

[0001] APPARATUS AND METHOD FOR CAUTERI Z ING TISSUE

[0002] Appl icant

[0003] Mermaid Medical , Inc .

[0004] Inventors

[0005] Adrian C . Ravenscro ft

[0006] Jul i zette C . Melgar

[0007] Chandler D . Reed

[0008] Re ference To Pending Prior Patent Applications Thi s patent application claims bene f it of :

[0009] ( i ) pending prior U . S . Provis ional Patent Appl ication Serial No . 63 / 789 , 685 , f i led 04 / 16 / 2025 by Mermaid Medical , Inc . for MECHANICAL CAUTERI Z ING BIOPSY DEVICE (Attorney' s Docket No . MERMAID-3 PROV) ; and

[0010] ( i i ) pending prior U . S . Provi s ional Patent Appl ication Serial No . 63 / 817 , 520 , f i led 06 / 04 / 2025 by Mermaid Medical , Inc . for CAUTERI Z ING BIOPSY DEVICE (M-SEAL ) (Attorney' s Docket No . MERMAID- 5 PROV) .

[0011] The two ( 2 ) above- identi f ied patent applications are hereby incorporated herein by re ference .

[0012] Field Of The Invention

[0013] Thi s invention relates to medical devices in general , and more particularly to novel cauteri zation

[0014] MERMAID- 0305 PCTapparatus for use during biopsy procedures, and novel methods for effecting cauterization of tissue .

[0015] Background Of The Invention

[0016] Tissue biopsy, in particular, soft tissue biopsy, is a commonly performed medical procedure used to make pathologic diagnoses of certain medical conditions (e . g. , cancer, etc . ) . Soft tissue biopsy is generally performed using a percutaneous, minimally-invasive approach in which a small sample of soft tissue is removed from a predetermined area (e . g. , the lung, the kidney, a lesion on the anatomy, etc . ) . Pathological examination of the small tissue sample so obtained can subsequently be used to make (or confirm) a diagnosis of a medical condition.

[0017] In order to facilitate effective, accurate pathological examination of the small tissue sample obtained by biopsy, it is necessary for the sample to meet at least the following criteria : adequate sample size, tissue integrity, intended target tissue, and biopsy reliability / patient comfort .

[0018] More particularly, in order to obtain adequate sample size, the sample obtained by biopsy must be of an appropriate size for the desired pathological examination. By way of example but not limitation, in certain liver biopsies, it has been found that biopsy sample sizes of approximately 1.5 cm - 3.0 cm in

[0019] MERMAID-0305 PCTlength are required to facilitate accurate pathological examination.

[0020] With respect to tissue integrity, it has been found that fragmentation of the tissue sample obtained by biopsy may interfere with visualization of key histologic features . Hence, in order to facilitate accurate pathological examination, the biopsy sample should be intact without any tissue fragmentation, to the greatest degree possible .

[0021] With respect to the requirement that the biopsy sample be obtained from the intended target tissue, it is important that the biopsy sample be taken from an appropriate region of the tissue to be sampled, e . g. , such that the biopsy sample obtained is representative of the larger tissue area of interest that is being evaluated .

[0022] Finally, although soft tissue biopsy is generally performed as a minimally-invasive procedure, it is important to minimize the number of times that the biopsy needle must be advanced into the patient' s tissue . Attempted biopsies that do not obtain sufficient tissue, or which obtain damaged tissue samples, generally require repetition of the biopsy procedure . Since such repeated procedures tend to lead to patient discomfort and increased procedure time (and hence increased expense) , it is desirable to obtain an adequate biopsy sample to facilitate

[0023] MERMAID-0305 PCTpathologic examination without having to repeat the biopsy procedure .

[0024] In general, two different approaches are commonly used to effect soft tissue biopsies : Fine Needle Aspiration Biopsy (FNAB) and Core Needle Biopsy (CNB) . Fine Needle Aspiration Biopsy (FNAB) draws cells out from soft tissue using a very small diameter needle and does not generally require the use of anesthesia . However, it has been found that FNAB yields very small samples, and the small samples obtained with FNAB often lead to unreliable analysis . As a result, CNB is generally preferred over FNAB since CNB generally provides larger sample sizes with superior tissue integrity than FNAB .

[0025] With Core Needle Biopsy (CNB) , an introducer needle is often used to access a target site in the soft tissue so as to introduce a biopsy device intended to cut and remove a core of the soft tissue at the tissue site which can subsequently be pathologically evaluated. Devices for performing CNB are generally configured to perform either a "side cut" biopsy or a "full core" biopsy. Regardless of whether CNB is used to perform "side cut" biopsy or "full core" biopsy, the CNB device must be configured to (i) core out a representative tissue sample from the target tissue, (ii) shear the tissue sample from the target tissue so that tissue sample is completely separated from the target tissue, and (iii) retain the

[0026] MERMAID-0305 PCTtissue sample within the device so that the tissue sample can be removed from the anatomy and collected for pathologic examination in a sterile manner.

[0027] More particularly, and looking now at Figs . 1 and 2, there is shown an exemplary prior art CNB "side cut" biopsy device 5 configured to perform a "side cut" biopsy. Biopsy device 5 generally comprises a handle (not shown) having an outer cannula 10 extending distally therefrom. Outer cannula 10 generally comprises a proximal end (not shown) , a distal end 15, and a lumen 20 extending therebetween. A stylet 25 comprising a proximal end (not shown) , a distal end 30, and a body 35 extending therebetween is slidably, coaxially disposed within lumen 20 of outer cannula 10 so as to be selectively movable relative to outer cannula 10. Body 35 of stylet 25 comprises a cut-out defining a sample chamber 40 disposed just proximal to distal end 30, whereby to receive a coredout soft tissue sample, as will hereinafter be discussed .

[0028] In use, side-cut biopsy device 5 is advanced so that the distal end of outer cannula 10 is disposed at the surface of the tissue to be sampled. Stylet 25 is then moved distally so as to enter into, and cut, the tissue that is to be sampled. Importantly, stylet 25 is advanced distally into the tissue to be sampled such that sample chamber 40 becomes filled with the tissue to be sampled. Specifically, stylet 25

[0029] MERMAID-0305 PCTcomprises a sharp distal end configured to effect coring of the tissue to be sampled. As used herein, the term "coring" refers to the cutting action effected when a sharp-edged stylet (or tube) performs tissue separation along a tract by using a leading edge; the term "shearing" refers to the cutting action effected when the end of the tissue sample is cut at the end of the throw length of stylet 25 (i . e . , when stylet 25 is in its distal most position) . Next, outer cannula 10 is advanced distally over stylet 25, with distal end 15 of outer cannula 10 shearing tissue as it moves distally so as to leave a sample of tissue in sample chamber 40. Outer cannula 10 and stylet 25 can thereafter be removed proximally from the tissue, with a core of tissue remaining in sample chamber 40, whereby to retain the sample of tissue in sample chamber 40.

[0030] Another type of biopsy device commonly used to perform soft tissue biopsy is the "full core" (sometimes also referred to as an "end-cut") biopsy device .

[0031] More particularly, and looking now at Figs . 3 and 4, there is shown an exemplary prior art CNB "full core" biopsy device 45 configured to perform a "end cut" biopsy. Biopsy device 45 generally comprises a handle (not shown) having an outer cannula 50 extending distally therefrom. Outer cannula 50 generally comprises a proximal end (not shown) , a

[0032] MERMAID-0305 PCTdistal end 55 terminating in a sharpened distal end surface 53 (i . e . , a sharpened end surface extending about the circumference of distal end 55) , a distal cutting feature (not shown) configured to selectively shear tissue when actuated, and a lumen 60 extending therebetween. A stylet 65 comprising a proximal end (not shown) , and a sharpened distal end 70 is coaxially disposed within lumen 60 of outer cannula 50. In use, stylet 65 is disposed within outer cannula 50 such that sharpened distal end 70 of stylet 65 is aligned with (or protrudes slightly distally from) distal end 55 of outer cannula 50 as full-core biopsy devices 45 is navigated through the tissue to the biopsy device . Full-core biopsy device 45 is advanced so that the distal end of outer cannula 50 is disposed at the proximal surface of the tissue to be sampled. Outer cannula 50 is then moved distally such that sharpened, distal end surface 53 of outer cannula 50 cores out the tissue that is to be sampled as sharpened distal end surface 53 performs separation of the tissue along the tract that it advances along and the distal cutting feature (not shown) is actuated to shear the tissue that is to be sampled from the native tissue . Outer cannula 50 can then be moved distally so that distal end 55 of outer cannula 50 passes over the tissue sample if necessary, whereby to encase and retain a tissue sample S within lumen 60 of outer cannula 50.

[0033] MERMAID-0305 PCTIt will be appreciated that both CNB "side cut" biopsy device 5 and CNB "full core" biopsy device 45 can be configured as either "semi automatic" or "fully automatic" devices . More particularly, and looking now at Figs . 4A, there is shown exemplary "side cut" biopsy device 5 configured as a "semi-automatic" device . With the "semi-automatic" configuration, the biopsy function of the device consists of only one action in which sample chamber 40 is positioned at the end of the sampling target before being moved distally into the tissue (i . e . , before being "fired") . With such a "semi-automatic" configuration, sample chamber 40 is advanced manually into the target tissue and then outer cannula 10 is subsequently moved distally over stylet 25 / sample chamber 40 upon the triggering of the actuation mechanism of CNB "side cut" biopsy device 5.

[0034] By contrast, with a "fully automatic" configuration and looking now at Fig. 4B, the distal movement of stylet 25 and outer cannula 10 into the tissue to be sampled comprises two actions . That is, with a "fully automatic" device stylet 25 and outer canula 10 are automatically moved distally in sequential actions triggering of the actuation mechanism of CNB "side cut" biopsy device 5.

[0035] Regardless of the approach utilized to effect a biopsy of soft tissue, some trauma to the tissue being biopsied (and any intervening tissue) is inevitable .

[0036] MERMAID-0305 PCTTrauma to soft tissue can result in excessive bleeding and / or other undesirable complications (e . g. , internal bleeding, etc . ) . Furthermore, in situations in which the biopsy needle penetrates a tumor or other cancerous growth, trauma to the tumor / cancerous growth may allow cells from the tumor / cancerous growth to spread to other tissues via the tissue tract created by the biopsy needle . This deleterious effect, sometimes referred to in the art as "needle-biopsy-associated needle tract seeding" is a concern whenever a biopsy procedure is performed in soft tissue . Soft tissue biopsy needles are generally of an extremely small diameter, specifically chosen to (i) result in a tissue sample S of adequate size for pathologic examination, while (ii) being no larger than necessary for adequate sampling so as to not result in excessive trauma / discomf ort to the patient . Thus, the "tissue tract" extending between the location of entry of the biopsy device (e . g. , the outer surface of the patient' s skin) and the location where a sample of tissue S is removed from the patient for examination (e . g. , an internal site within the patient' s anatomy) is typically of the same, very small diameter as the biopsy needle . In order to address trauma to such intervening tissue (i . e . , the tissue surrounding the "tissue tract") , a surgical procedure cauterizer may be employed to heat the intervening tissue to a sufficient temperature to cause simultaneous protein

[0037] MERMAID-0305 PCTcoagulation and tissue desiccation (dehydration) to occur. Such cauterization acts to staunch bleeding in tissue lining the tissue tract and minimize the risk of adverse outcomes due to tissue trauma. By way of example but not limitation, such cauterization is typically achieved by using a surgical cauterizer configured to heat the tissue to 60-100 °C .

[0038] While surgical cauterizers exist in the prior art, it can be challenging to deliver the correct amount of heat to the tissue that is to be cauterized. This is particularly true in the case of a biopsy procedure in which the "tissue tract" frequently passes through layers of different types of tissue .

[0039] It has been suggested in the art to utilize a guide needle to access an internal site at which a soft tissue biopsy is to be performed and, once the biopsy has been successfully performed using an appropriate biopsy device disposed in the guide needle, to remove the biopsy device from the guide needle and insert a probe having a heated (i . e . , cauterizing) distal tip into the guide needle, whereby to use the probe to cauterize the internal site of the biopsy (i . e . , by extending the probe out of the distal end of the guide needle such that the probe contacts the tissue to be cauterized) . And, if desired, the same prior art approach has been suggested to cauterize the tissue tract (i . e . , by extending the probe out of the distal end of the guide needle such

[0040] MERMAID-0305 PCTthat the probe contacts the tissue surrounding the tissue tract as the probe / guide needle is retracted proximally out of the anatomy) .

[0041] However, such prior art biopsy needle cauterizers and methods suffer from significant limitations .

[0042] Specifically, prior art probe-style cauterizers, such as the SinglePass device manufactured by Single Pass, Inc of Lake Forrest, CA, utilize a probe which is configured to only provide a cauterizing effect at a single, pre-set temperature . It will be appreciated that the tissue tract may pass through various types / layers of tissue (e . g. , fat, muscle, fibrous tissue, etc. ) in order to reach the internal biopsy site . It should also be appreciated that, where a surgical cauterizer is configured to cauterize tissue by transferring heat from a cauterizer element to the tissue directly, the tissue acts as a "heat sink", drawing heat away from the cauterizer element as the tissue is cauterized. It will be appreciated that different tissue has different heat sink / heat distribution properties, depending on the tissue . By way of example but not limitation, tissue with high density (e . g. , higher amount of fibrous and glandular connective tissue compared to fatty tissue) is generally more resistant to the transfer of heat than tissue with lower density (e . g. , fat) , meaning that more heat must be applied to higher density tissue to achieve the desired degree of cauterization than needs

[0043] MERMAID-0305 PCTto be applied to lower density tissue to achieve the same cauterizing effect . Other variables, such as the degree of perfusion of a tissue by blood, may also affect the heat sink properties of the tissue being cauterized.

[0044] Without a way to both monitor and adjust the heat applied to the tissue during direct cauterization, prior art cauterizing devices frequently apply too little (or too much) heat to the anatomy during a cauterizing procedure, whereby to either fail to effectively cauterize the tissue, or to over-cauterize the tissue and potentially cause additional trauma (e . g. , burning or carbonization) to the patient .

[0045] Thus there exists a need in the art for a new and improved cauterizer which facilitates real-time temperature monitoring and control over the cauterizing temperature, and also a new and improved cauterizer which combines a cauterizer and a biopsy tool into a single device .

[0046] Summary Of The Invention

[0047] The present invention comprises the provision and use of a new and improved cauterizer which facilitates real-time temperature monitoring and control over the cauterizing temperature, and also a new and improved cauterizer which combines a cauterizer and a biopsy tool into a single device .

[0048] MERMAID-0305 PCTIn a preferred form of the invention, there is provided apparatus for cauterizing tissue, said apparatus comprising:

[0049] a handle;

[0050] a probe mounted to said handle, said probe comprising :

[0051] a distal end, a proximal end, and a lumen extending therebetween, said distal end being characterized by a distal end region that extends a predetermined distance proximally from said distal end;

[0052] a heating element configured to emit heat so as to heat said distal end region of said probe when an electric current is passed through said heating element ;

[0053] a temperature sensor configured to measure the instantaneous temperature of said distal end region of said probe, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;

[0054] a power source;

[0055] an electronics module comprising:

[0056] a voltage regulator;

[0057] a controller; and

[0058] an amplifying transistor;

[0059] wherein said power source is electrically connected to said controller and to said amplifying transistor;

[0060] MERMAID-0305 PCTwherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;

[0061] wherein said amplifying transistor is electrically connected to said heating element of said probe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; and

[0062] wherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition.

[0063] In another preferred form of the invention, there is provided a method for cauterizing tissue, said method comprising:

[0064] providing apparatus for cauterizing tissue, said apparatus comprising:

[0065] a handle;

[0066] a probe mounted to said handle, said probe comprising :

[0067] a distal end, a proximal end, and a lumen extending therebetween, said distal end being

[0068] MERMAID-0305 PCTcharacterized by a distal end region that extends a predetermined distance proximally from said distal end;

[0069] a heating element configured to emit heat so as to heat said distal end region of said probe when an electric current is passed through said heating element;

[0070] a temperature sensor configured to measure the instantaneous temperature of said distal end region of said probe, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;

[0071] a power source;

[0072] an electronics module comprising:

[0073] a voltage regulator;

[0074] a controller; and

[0075] an amplifying transistor;

[0076] wherein said power source is electrically connected to said controller and to said amplifying transistor;

[0077] wherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;

[0078] wherein said amplifying transistor is electrically connected to said heating element of said

[0079] MERMAID-0305 PCTprobe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; and

[0080] wherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition;

[0081] using said controller to emit a control signal to said amplifying transistor to pass current to said heating element such that said heating element is heated to a predetermined temperature, wherein said control signal cycles said amplifying transistor ON and OFF at a first predetermined frequency;

[0082] using said controller to monitor the instantaneous temperature of said distal end region of said probe, wherein said instantaneous temperature of said distal end region of said probe comprises the instantaneous temperature of said emitted temperature signal from said temperature sensor;

[0083] comparing said instantaneous temperature to said predetermined temperature;

[0084] using a control signal to cycle said amplifying transistor ON and OFF at a second predetermined frequency, wherein said second predetermined frequency is (i) a higher frequency than said first

[0085] MERMAID-0305 PCTpredetermined frequency if said instantaneous temperature is lower than said predetermined temperature, and (ii) a lower frequency than said first predetermined frequency if said instantaneous temperature is higher than said predetermined temperature .

[0086] In another preferred form of the invention, there is provided apparatus for cauterizing tissue, said apparatus comprising:

[0087] a handle;

[0088] an outer cannula comprising a distal end, a proximal end, and a lumen extending therebetween;

[0089] an inner cannula comprising a distal end, a proximal end, and a lumen extending therebetween, said inner cannula being disposed coaxially within said lumen of said outer cannula so as to be selectively slidable relative thereto;

[0090] a trocar comprising a distal end, a proximal end, and a central cavity extending therebetween, said distal end being characterized by a distal end region that extends a predetermined distance proximally from said distal end of said trocar, said trocar being disposed coaxially within said lumen of said inner cannula such that said inner cannula and said outer cannula are selectively slidable relative to said trocar;

[0091] a heating element, said heating element being configured to emit heat so as to heat said

[0092] MERMAID-0305 PCTdistal end region of said trocar when an electric current is passed through said heating element;

[0093] a temperature sensor disposed in said central cavity of said trocar, said temperature sensor being configured to measure the instantaneous temperature of said distal end region of said trocar, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;

[0094] a power source;

[0095] an electronics module comprising:

[0096] a voltage regulator;

[0097] a controller; and

[0098] an amplifying transistor;

[0099] wherein said power source is electrically connected to said controller and to said amplifying transistor;

[0100] wherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;

[0101] wherein said amplifying transistor is electrically connected to said heating element of said probe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said

[0102] MERMAID-0305 PCTheating element when said amplifying transistor is in the OFF condition; and

[0103] wherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition.

[0104] Brief Description Of The Drawings

[0105] These and other obj ects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:

[0106] Figs . 1 and 2 are schematic views showing an exemplary prior art CNB "side cut" biopsy device configured to perform a "side cut" biopsy;

[0107] Figs . 3 and 4 are schematic views showing an exemplary prior art CNB "full core" biopsy device configured to perform a "end cut" biopsy;

[0108] Figs . 4A and 4B are schematic views, illustrating the operation of an exemplary prior art CNB "side cut" biopsy device;

[0109] Figs . 5, 6, 6A and 6B are schematic views showing a novel cauterizing device formed in accordance with the present invention;

[0110] MERMAID-0305 PCTFigs . 6C, 7, 8 and 9 are schematic views showing further aspects of the novel cauterizing device of Figs . 5, 6, 6A and 6B;

[0111] Figus 10, 10A, 11 and 12 are schematic views showing a novel biopsy-and-cauterizing apparatus formed in accordance with the present invention;

[0112] Figs . 12A, 12B, 13 and 14 are schematic views showing further aspects of the novel biopsy-and-cauterizing apparatus of Figs . 10, 10A, 11 and 12 ;

[0113] Fig. 15 is a schematic view showing further aspects of the novel biopsy-and-cauterizing apparatus of Figs . 10, 10A, 11 and 12;

[0114] Figs . 16, 16A and 16B are schematic views showing a further embodiment of a novel biopsy-and-cauterizing apparatus formed in accordance with the present invention;

[0115] Figs . 17-19 are schematic views showing an exemplary cauterization procedure in tissue utilizing the novel apparatus of the present invention;

[0116] Fig. 20 is a schematic view showing another embodiment of a novel biopsy-and-cauterizing apparatus formed in accordance with the present invention; and Fig. 21 is a schematic view showing still another embodiment of a novel biopsy-and-cauterizing apparatus formed in accordance with the present invention.

[0117] MERMAID-0305 PCTDetailed Description Of The Preferred Embodiments The present invention comprises the provision and use of a new and improved cauterizer which facilitates real-time temperature monitoring and control over the cauterizing temperature, and also a new and improved cauterizer which combines a cauterizer and a biopsy tool into a single device .

[0118] Novel Cauterizing Device ("M-Seal") Looking now at Fig. 5, there is shown a novel cauterizer device 105 formed in accordance with the present invention. Cauterizer device 105 generally comprises a handle 110 and a probe shaft 115 extending distally therefrom. More particularly, handle 110 generally comprises a distal end 120, a proximal end 125, and a handle body 130 enclosing a handle cavity 135 (Fig. 6) extending therebetween.

[0119] Looking now at Figs . 5, 6, 6A, 6B, 6C, 7 and 8, probe shaft 115 generally comprises a distal end 140, a proximal end 145, and a lumen 150 (Fig 7 ) extending therebetween. Distal end 140 of probe shaft 115 terminates in a blunt distal surface 155, whereby to fluidically seal lumen 150 at distal end 140. It will be appreciated that probe shaft 115 is formed out of a heat-transmissive material (e . g. , stainless steel, etc . ) whereby to transfer heat from a heating element disposed in lumen 150 through a sidewall 160 (Fig. 7 )

[0120] MERMAID-0305 PCTof probe shaft 115 (and / or sidewall of a distal cap mounted to probe shaft 115, see below) to an exterior distal surface area 165 / distal surface 155 of distal end 140 of probe shaft 115, as will hereinafter be discussed in further detail . In one preferred form of the present invention, probe shaft 115 comprises a distal cap 157 mounted to distal end 140 so as to enclose the distalmost portion of lumen 150. See Fig.

[0121] 6C .

[0122] More particularly, and looking now at Figs . 7 and 8, a heating element 170 is disposed in lumen 150 of probe shaft 115 so as to be in contact with a sidewall 160 of probe shaft 115 (and / or to the sidewall of distal cap 157 ) . It will be appreciated that, as used herein, the term "exterior distal surface area 165" is intended to refer to the exterior surface of the distal end of probe shaft 115 and, if distal cap 157 is provided, to the exterior surface of distal cap 157, as will be apparent to one of skill in the art in view of the present disclosure . Heating element 170 preferably comprises a resistor, whereby to generate heat as an electric current is flowed through heating element 170, as will be apparent to one of skill in the art in view of the present disclosure . In one preferred form of the present invention, heating element 170 comprises a "coil-shaped" resistor having a plurality of turns that contact sidewall 160 of probe shaft 115, whereby to transfer heat from heating

[0123] MERMAID-0305 PCTelement 170 to sidewall 160, through sidewall 160, and to exterior distal surface area 165 / distal surface 155. However, it should be appreciated that, if desired, heating element 170 may be provided in the form of a resistive band that contacts sidewall 160 and effects heat generation and transfer in substantially the same manner, as will be apparent to one of skill in the art in view of the present disclosure . It will be appreciated that, if desired, an appropriate insulating layer (not shown) may be provided between heating element 170 and sidewall 160 so as to facilitate even distribution of heat through sidewall 160 and / or distal cap 157 and / or distal surface 155 and / or electrically isolate current from a patient .

[0124] A pair of electrical leads 175, 180 extend from an electronics module 185 (Figs . 7 and 8 ) disposed in handle cavity 135 through lumen 150 of probe shaft 115 so as to selectively pass electric current through heating element 170 as will hereinafter be discussed. By way of example but not limitation, lead 175 may be connected to the anode of an electrical circuit and lead 180 may be connected to the cathode of an electrical circuit, such that electric current can be selectively passed from the anode of an electrical circuit via lead 175, through heating element 170 (whereby to generate heat) and back to the cathode of an electrical circuit, as will be apparent to one of

[0125] MERMAID-0305 PCTskill in the art in view of the present disclosure . Specifically, heating element 170 preferably converts electrical energy (i . e . , current) into heat via Joule heating (i . e . , P=I2R) . In order to achieve significant heat generation, heating element 170 is preferably made of a material having a high electrical resistance, such that when current passes through heating element 170, heating element 170 heats up (whereby to dissipate heat to adjacent components, such as sidewall 160, exterior distal surface area 165, and distal cap 155. It will be appreciated that, by contrast, electrical leads 175, 180 comprise a low-resistance material of the sort known in the art so as to not act as heat-generating resistors when electric current is passed through leads 175, 180. By way of example but not limitation, heating element 170 may comprise nickel-chromium (Nichrome) , iron-chromium-aluminum alloy (Kanthal) , copper-nickel (Curponickel ) , stainless steel, etc . Another method to control resistance of a lead wire is by changing the diameter of the wire . Electrical wire resistance is inversely proportional to its diameter: thicker wires (lower AWG number) have lower resistance and higher ampacity, while thinner wires (higher AWG number) have higher resistance . Resistance is calculated based on the material ' s resistivity, length, and cross-sectional area, with resistance doubling or halving roughly every 3 AWG sizes .

[0126] MERMAID-0305 PCTA temperature sensor 190 is mounted within lumen 150 of probe shaft 115 so as to be in contact with sidewall 160 of probe shaft 115 (and / or the sidewall of distal cap 157) , whereby to obtain temperature data corresponding to the temperature of sidewall 160 of shaft 115 (and hence, the temperature of exterior distal surface area / distal cap 155) . By way of example but not limitation, temperature sensor 190 may comprise a thermistor, thermocouple, or Resistance Temperature Detector (RTD) , however, it should be appreciated that temperature sensor 190 may comprise substantially any device configured to convert thermal energy into an electrical signal that can be read by a controller, as will be apparent to one of skill in the art in view of the present disclosure . One or more temperature leads 195 electrically connects temperature sensor 190 to electronics module 185, whereby to facilitate transmission of a temperature signal from temperature sensor 190 to electronics module 185. As a result of this construction, the present invention facilitates selective, temperaturedependent control over heating element 170, as will hereinafter be discussed in further detail .

[0127] Looking now at Fig. 9, electronics module 185 generally comprises a voltage regulator 200, a controller 205, and an amplifying transistor 210.

[0128] More particularly, controller 205 comprises at least a microprocessor and non-transient memory

[0129] MERMAID-0305 PCTconfigured to store appropriate instructions for operating the microprocessor, as will be apparent to one of skill in the art in view of the present disclosure . In one preferred embodiment of the present invention, controller 205 comprises a Proportional Integral Derivative (PID) microprocessor controller configured to output a Pulse Width Modulation (PWM) signal 215 that varies depending on the temperature signal received from temperature sensor 190, whereby to allow for the continuous control over the application of voltage applied to heating element 170 via amplifying transistor 210, as will hereinafter be discussed in further detail .

[0130] Specifically, Pulse Width Modulation (PWM) refers to a technique for controlling the flow of an analog power source using a digital signal to rapidly switch the current flow ON and OFF. The term "duty cycle" as used herein refers to the ratio of time that the PWM signal is "high" (i . e . , ON) versus "low" (i . e . , OFF) . Hence, the PWM signal permits precise control over the average power delivered to a load. In one preferred form of the present invention, amplifying transistor 210 comprises a metal-oxide semiconductor field-effect (MOSFET) transistor in either a p-channel or n-channel configuration. When so configured, amplifying transistor 210 comprises three terminals (i . e . , gate, drain, and source) , with the gate being connected to signal output from controller 205 (e . g. , PWM signal

[0131] MERMAID-0305 PCT215) , the drain connected to heating element 170, and the source supplied from ground.

[0132] A power source 220 (e . g. , a battery configured to provide an appropriate current to electronics module 185) is provided in electrical connection with voltage regulator 200. If desired, power source 220 may be provided in the form of a removable battery pack (see Fig. 6) such that power source 220 may be charged separate from cauterizing device 105 (and / or replaced / reused, etc . ) , as will be apparent to one of skill in the art in view of the present disclosure . It will be appreciated that power source 220 preferably delivers Direct Current (DC) to electronics module 185.

[0133] Alternatively, and looking now at Figs . 6A and 6B, if desired, power source 220 may be provided an external battery pack electrically connected to handle 110 (and hance to electronics module 185) via an external power lead 222.

[0134] It will be appreciated that providing power source 220 in the form of an external battery pack provides numerous advantages . Specifically, where power source 220 is provided as an external battery pack, power source 220 may remain outside of the sterile field during a cauterizing procedure, with the benefit that power source 220 itself need not be sterile . Moreover, providing power source 220 as an external battery pack permits disposal / recycling of

[0135] MERMAID-0305 PCTpower source 220 separate from the "medical waste" that characterizes the remainder of cauterizing device 105. Still another significant advantage of providing power source 220 as an external battery pack is the reduction in weight of handle 115. Reducing the weight of handle 110 is significant, since such reduction greatly facilitates enhanced dexterity and reduces fatigue on the physician, leading to more accurate procedures and superior outcomes .

[0136] It will be appreciated that electronics module 185 of the present invention permits two different ways to regulate the current flowing to heating element 170 (and hence, the cauterizing effect of cauterizing device 105) .

[0137] Specifically, it will be appreciated that in a first mode of operation, electronics module 185 permits continuous control over voltage applied to heating element 170 by monitoring, in real time, the temperature of sidewall 160 / exterior distal surface area 165 via temperature sensor 190, and adjusting (i . e . , cycling the duty cycle ON / OFF) the current delivered to heating element 170 as necessary in order to maintain a desired temperature . By way of example but not limitation, if it is desired to apply a cauterizing temperature of 95°C to tissue using cauterizing device 105, temperature sensor 190 can be used to monitor the temperature of sidewall 160 / exterior distal surface area 165 via providing an

[0138] MERMAID-0305 PCTappropriate temperature signal to controller 205.

[0139] Controller 205 then compares, in real time, the temperature signal reflecting the actual temperature of sidewall 160 / exterior distal surface area 165 and adjusts the current flowing from amplifying transistor 210 to heating element 170 as necessary (e . g. , increases the frequency of the ON / OFF duty cycle of the current flow to heating element 170 if the temperature signal reflects a temperature lower than the desired cauterizing temperature, and decreases the frequency of the ON / OFF duty cycle of the current flow to heating element 170 if the temperature signal reflects a temperature higher than the desired cauterizing temperature) .

[0140] By way of example but not limitation, a "50% duty cycle" refers to a cycle in which the current being cycled is ON for half of the time of a given cycle; a "100% duty cycle" refers to a cycle in which the current for the entire time of a given cycle; a "0% duty cycle" refers to a cycle in which the current is OFF for the entire time of a given cycle . Generally such duty cycles are described in terms of cycles per second (i . e . , a duty cycle having a frequency of 1H:is equal to 1 cycle per second) , as will be apparent to one of skill in the art in view of the present disclosure . Thus it is possible to control the average voltage delivered to heating element 170 by controlling the duty cycle (e . g. , via PWM signal 215

[0141] MERMAID-0305 PCTin the manner discussed above) . That is, average voltage delivered is equal to peak voltage supplied x the duty cycle . The ability to monitor and adjust the ON / OFF state (i . e . , the duty cycle) of the current to heating element 170 in real time is a significant advance in the art, as it both facilitates efficient cauterizing of tissue while avoiding burnout of the cauterizer probe (i . e . , such as may occur if the heating element were to be activated before the probe were to be disposed in the tissue to be cauterized) . With this mode of operation, it will be appreciated that the Pulse Width Modulation (PWM) signal 215 can be used to control amplifying transistor 210 by providing the appropriate frequency for the ON / OFF duty cycle required for achieving the desired temperature, as will be apparent to one of skill in the art in view of the present disclosure .

[0142] In a second mode of operation, electronics module 185 can be pre-programmed (e . g. , via appropriate software stored on non-volatile memory of controller 205) to permit control over voltage applied to heating element 170 according to a predetermined temperature profile . With this form of the invention, it is possible to program controller 205 to provide current to heating element 170 in a predetermined manner (e . g. , an ON / OFF duty cycle in the form of a stepwisefunction where temperature of heating element 170 is increased over a predetermined period of time

[0143] MERMAID-0305 PCTaccording to a predetermined, stepped profile) . By way of example but not limitation, Pulse With Modulation (PWM) signal 215 may be appropriately adjusted to control amplifying transistor 210 in a manner that effects the desired frequency of the ON / OFF duty cycle of the current flow to heating element 170, as will be apparent to one of skill in the art in view of the present disclosure .

[0144] In a preferred embodiment of the present invention, controller 205 comprises a Proportional-Integral-Derivative (PID) controller, a feedback-based control loop mechanism which may be used to manage machines and processes that require continuous control and automatic adjustment . A PID controller is ideal where control through modulation is necessary without human intervention. The PID controller automatically compares the desired target value (setpoint of SP) , e . g. , a target cauterization temperature, with the actual value of the system (process variable or PV) , e . g. , the instantaneous temperature received from temperature sensor 190. The difference between these two values is called the error value, denoted as e (t) . The PID controller then applies corrective actions automatically to bring the PV to the same value as the SP using three methods : The proportional (P) component responds to the current error value by producing an output that is directly proportional to the magnitude of the error. This provides immediate

[0145] MERMAID-0305 PCTcorrection based on how far the system is from the desired setpoint . The integral (I) component, in turn, considers the cumulative sum of past errors to address any residual steady-state errors that persist over time, eliminating lingering discrepancies .

[0146] Lastly, the derivative (D) component predicts future error by assessing the rate of change of the error, which helps to mitigate overshoot and enhance system stability, particularly when the system undergoes rapid changes . The PID output signal (i . e . , PWM signal 215) can directly control the duty cycle of current passed to heating element 170. The PID controller reduces the likelihood of human error and improves automation.

[0147] In one preferred form of the present invention, a switch 225 is provided (e . g. , on handle body 130 of handle 110) so as to permit the surgeon to control heat activation by turning controller 205 "ON" or "OFF" (i . e . , such that electronics module 185 provides current via amplifying transistor 210 to heating element 170 when switch 225 is in the "ON" condition; and does not provide current via amplifying transistor 210 to heating element 170 when switch 225 is in the "OFF" condition) . Switch 225 may be configured as a "momentary switch" (i . e . , so as to activate electronics module 185 upon a sustained press of switch 225 by the surgeon) , or a "latching switch" (i . e . , so as to activate electronics module 185 upon a

[0148] MERMAID-0305 PCTsingle press of switch 225 by the surgeon) . The switch can also be configured to send a pulse to the electronics modules whereby a first press "latches" the circuit "ON" (via logic) and a second press "unlatches" the circuit to "OFF" (via logic) . An indicator 230 is preferably provided (e . g. , on handle body 130 of handle 110 or on electronics module 185 so as to be visible through an opening formed in handle body 130, as will be apparent to one of skill in the art in view of the present disclosure) so as to show the surgeon the instantaneous temperature of the sidewall 160 / exterior distal surface area 165 of probe shaft 115 (and / or the status of the heating element, etc . ) . Furthermore, if desired, switch 225 may be configured to permit the surgeon to select and set a desired cauterizing temperature (i . e . , a temperature that electronics module 185 then causes sidewall 160 / exterior distal surface area 165 to attain via the aforementioned circuit and heating element 170) , as will be apparent to one of skill in the art in view of the present disclosure .

[0149] It should also be appreciated that, if desired, handle 110 may further comprise a main power switch (not shown) disposed on the proximal most surface of the handle body 130 to permit selective electrical disconnected of power source 220 from electronics module 185. Furthermore, if desired, handle 110 may further comprise a speaker (not shown) for providing

[0150] MERMAID-0305 PCTaudible feedback to the surgeon (e . g. , a chirp when sidewall 160 / exterior distal surface area 165 has attained a desired temperature) and / or an appropriate haptic feedback mechanism (not shown) to provide vibrational feedback to the surgeon, (e . g. , a quick vibration when sidewall 160 / exterior distal surface area 165 has attained a desired temperature) .

[0151] And it should also be appreciated that, if desired, controller 205 may comprise an appropriate initialization sequence stored in non-volatile memory and an appropriate test function to ensure that all elements in electronics module 185 (and heating element 170, temperature sensor 190, etc. ) are properly functioning before use of cauterizing device 105. An appropriate test function that could be performed on the controller as part of the initialization sequence are continuity tests .

[0152] In use, cauterizing device 105 is utilized as follows . First, a surgical procedure is performed using a guide needle having an open distal end. By way of example but not limitation, such a surgical procedure may be a biopsy of soft tissue using an appropriate biopsy device (not shown) disposed in the guide needle . Once the surgical procedure is completed, the surgical apparatus (e . g. , a biopsy device disposed in the guide needle) is removed, leaving the guide needle in place in the anatomy.

[0153] MERMAID-0305 PCTNext, cauterizing device 105 is introduced into the guide needle such that distal end 140 (specifically, the portion of distal end 140 comprising exterior distal surface area 165 and distal surface 155) extends distally of the distal most end of the guide needle, whereby to contact the anatomy in the region where the surgical procedure has been performed .

[0154] With cauterizing device 105 in place such that distal end 140 contacts the anatomy in the region of the surgical procedure has been performed, the surgeon activates electronics module 185 (e . g. , via switch 225) so as to cause heating element 170 to heat up and transfer heat to exterior distal surface area 165 / distal surface 155 in the manner discussed above . It will be appreciated that inasmuch as the tissue of the anatomy contacted by exterior distal surface area 165 / distal surface 155 of probe shaft 115 acts as a heat sink, the temperature of exterior distal surface area 165 / distal surface 155 as registered by temperature sensor 190 is adjusted in real-time by controller 205 responding to the real-time temperature by increasing / decreasing the current provided to heating element 170 (see above) so as to provide and maintain the desired cauterizing temperature .

[0155] Once exterior distal surface area 165 / distal surface 155 has reached the appropriate cauterizing temperature, the tissue in contact with exterior

[0156] MERMAID-0305 PCTdistal surface area 165 / distal surface 155 is appropriately cauterized. The surgeon can then withdraw both the guide needle and cauterizing device 105 proximally (e . g. , in concert with one another) , such that exterior distal surface area 165 / distal surface 155 is in contact with the tissue adjacent to the "tissue tract" that was previously formed by insertion of the guide needle into the anatomy and cauterizes the "tissue tract" as the guide needle and cauterizing device 105 are withdrawn proximally from the anatomy. It will be appreciated that real-time temperature monitoring and adjustment of current (i . e . , the switching ON / OFF of the duty cycle) provided to heating element 170 preferably continues while cauterizing device 105 is withdrawn proximally, such that the temperature of exterior distal surface area 165 / distal surface 155 can be adjusted in realtime to address the different types of tissue encountered along the "tissue tract" . In this manner, cauterizing device 105 facilitates efficient cauterizing of the surgical site and the "tissue tract" between the patient' s skin and the surgical site .

[0157] It should also be noted that, if desired, cauterizing device 105 may be used to effect cauterization of tissue without the use of any guide needle . Specifically, and as noted above, one significant advantage of cauterizing device 105 of the

[0158] MERMAID-0305 PCTpresent invention over prior art cauterizing devices is that cauterizing device 105 can be operated outside of the anatomy (i . e . , in an environment in which there is no "heat sink" of tissue to absorb heat, such as the ambient air of the operating room) . This is because the provision of temperature sensor 190 (and electronics module 185 configured to adjust current delivered to heating element 170 in response to the detected temperature) permits operation of cauterizing device 105 in such an environment by halting current to heating element 170 when temperature sensor 190 reaches a predetermined maximum temperature, such that heating element 170 does not overheat (i . e . , "burn out") when disposed outside of the anatomy.

[0159] Novel Biopsy Device With Integrated Cauterizing Device As discussed above, effecting cauterization of tissue along a "tissue tract" created during a biopsy procedure of an internal surgical site presents significant challenges . One solution to the problems inherent in such cauterizing has been the use of a separate cauterizer that is introduced into a biopsy guide needle (after removing the biopsy apparatus from the guide needle) such that the distal end of the cauterizer extends out of the distal end of the biopsy guide needle and can effect cauterizing of adj acent tissue using the distal end of the cauterizer.

[0160] However, such an approach requires the use of two

[0161] MERMAID-0305 PCTseparate surgical instruments (e . g. , biopsy apparatus and a separate cauterizing apparatus) .

[0162] To address the foregoing issues, in another embodiment of the present invention, and looking now at Figs . 10, 10A, 11 and 12, there is shown a novel combined biopsy-and-cauterizing apparatus 305 formed in accordance with the present invention. Apparatus 305 is configured to perform a soft tissue biopsy utilizing an outer cannula 310 and a selectively movable, inner cannula 315 configured to move relative to outer cannula 310 (or to remain stationary while outer cannula 310 moves relative to inner cannula 315) . Inner cannula 315 is configured to coaxially pass over and a trocar 320 such that outer cannula 310 and inner cannula 315 can be selectively retracted proximally so as to expose a sharpened distal tip of trocar 320. In one preferred form of the invention, outer cannula 310, inner cannula 315 and trocar 320 are configured to perform a biopsy in the same manner as the biopsy tool disclosed in International (PCT) Patent Application No . PCT / US26 / 13648, filed 02 / 03 / 2026 for APPARATUS AND METHOD FOR PERFORMING TISSUE BIOPSY (Attorney' s Docket No . : MERMAID-0206 PCT) , which patent application is hereby incorporated by reference .

[0163] Looking now at Figs . 12A, 12B, , 13 and 14, trocar 320 comprises a sharpened distal tip 325 for facilitating distal movement of apparatus 305 / trocar

[0164] MERMAID-0305 PCT320 through soft tissue when trocar 320 is disposed distal to the distal end of outer cannula 310 and inner cannula 315, e . g. , when outer cannula 310 and inner cannula 315 are retracted proximally so as to expose sharpened distal tip 325 of trocar 320 (Fig. 10A) .

[0165] Outer cannula 310 comprises a distal end 330, a proximal end 335, and a lumen 340 extending therebetween. Proximal end 335 of outer cannula 310 is mounted to a handle 345. Distal end 330 of outer cannula 310 terminates in an opening 350 which opens on lumen 340. Inner cannula 315 comprises a distal end 346, a proximal end 347 (not shown) mounted to handle 345, and a lumen 348 extending therebetween. Inner cannula 315 is configured to be slidably, coaxially disposed in lumen 340 of outer cannula 310 such that outer cannula 310 and inner cannula 315 can be moved independently relative to one another, whereby to facilitate the performance of a biopsy procedure utilizing outer cannula 310 and / or inner cannula 315 (e . g. , insertion into anatomy and target tissue, sampling of tissue, and retrieval of a tissue sample for pathologic examination) . By way of example but not limitation, outer cannula 310 and inner cannula 315 may be configured to be selectively disposed proximally so as to expose / sharpened distal tip 325 of trocar 320, in order to use trocar 320 to

[0166] MERMAID-0305 PCTperform a cauterizing procedure as will hereinafter be discussed in further detail .

[0167] It will be appreciated that handle 345 may be provided with appropriate means (e . g. , springs, etc. ) to permit the relative position of outer cannula 310 and inner cannula 315 to be selectively adjusted and advanced with sufficient force to effect a biopsy procedure, etc . , as will be apparent to one of skill in the art in view of the present disclosure . By way of example but not limitation, handle 345 may comprise any of the mechanisms and / or needle / cannula / trocar arrangements disclosed in International (PCT) Patent Application No . PCT / US26 / 13648, filed 02 / 03 / 2026 for APPARATUS AND METHOD FOR PERFORMING TISSUE BIOPSY

[0168] (Attorney' s Docket No . : MERMAID-0206 PCT) , which patent application is hereby incorporated by reference .

[0169] Looking now at Figs . 12B, 13 and 14, in one preferred embodiment of the present invention trocar 320 comprises a central cavity 349 extending from a proximal end of trocar 320 to an endwall 351 disposed proximal to sharpened distal tip 325. A heating element 355 is provided within central cavity 349 in the region of endwall 351 so as to be in contact with the sidewall of trocar 320 in order to permit the transmission of heat from heating element 355 through the (heat-transmissive) sidewall of trocar 320 to an external distal surface 360 (Fig. 14 ) and / or to

[0170] MERMAID-0305 PCTsharpened distal tip 325. In a preferred embodiment, heating element 355 (sometimes hereinafter referred to as a "heating coil") comprises a resistor configured to heat up and emit heat when an electric current is passed through heating element 355, as will be apparent to one of skill in the art in view of the present disclosure .

[0171] A pair of electrical leads 375, 380 extend from handle 345 to heating element 355 through central cavity 349 and are electrically connected to heating element 355, whereby to permit an electric current to be passed from an electronics module 385 disposed in handle 345 (Fig. 16) through electrical lead 375, into and through heating element 355, through electrical lead 380 and back to electronics module 385. By way of example but not limitation, electrical lead 375 may be connected to the anode of an electrical circuit 390 of electronics module 385, and electrical lead 380 may be connected to the cathode of electrical circuit 390, as will be apparent to one of skill in the art in view of the present disclosure . It will be appreciated that, inasmuch as heating element 355 comprises an electrical resistor, the passage of current through heating element 355 causes the temperature of heating element 355 to increase as a result of electrical resistance . Moreover, it will also be appreciated that, as a result of the foregoing construction, electronics module 385 / electrical circuit 390 may be

[0172] MERMAID-0305 PCTused to selectively control the current passed to heating element 355 so as to permit control over timing of heat generation and / or the temperature of heating element 355 in order to facilitate efficient cauterization, as will hereinafter be discussed in further detail .

[0173] A temperature sensor 395 is mounted within central cavity 349 of trocar 320 so as to provide a temperature signal representing the instantaneous temperature of exterior surface 360 of trocar 320 to electronics module 385 via a temperature sensor lead 400 extending through central cavity 349. By way of example but not limitation, temperature sensor 395 may comprise a thermistor, thermocouple, or Resistance Temperature Detector (RTD) , however, it should be appreciated that temperature sensor 395 may comprise substantially any device configured to convert thermal energy into an electrical signal that can be read by a controller, as will be apparent to one of skill in the art in view of the present disclosure . See Fig. 13.

[0174] Looking now at Fig. 15, there is shown further details of electrical circuit 390 of electronics module 385 according to one embodiment of the present invention .

[0175] It will be appreciated that electronics module 385 functions identically to electronic module 185 discussed in detail above . In this form of the invention, heating element 355 is controlled by a

[0176] MERMAID-0305 PCTcontroller 405 (e . g. , a Proportional Integral Derivative (PID) controller) comprising a suitable microprocessor and non-volatile memory (not shown) . Direct current (DC) from a power source 410 (e . g. , a battery) pass through a voltage regulator 415 to controller 405 and to an amplifying transistor 420 controlled by controller 405, in the same manner as with electronics module 185 discussed above . It will be appreciated that power source 410 preferably delivers Direct Current (DC) to electronics module 385. By way of example but not limitation, amplifying transistor 420 may comprise a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) .

[0177] Electric current may be selectively flowed from amplifying transistor to heating element 355 (which heating element 355, comprising a resistor, heats up as current is passed through it) , as will hereinafter be discussed in further detail .

[0178] It should be appreciated that, if desired, the temperature of heating element 355 may be controlled via controller 405. With this form of the invention, controller 405 preferably comprises a Proportional Integral Derivative (PID) controller configured to emit a Pulse Width Modulation (PMW) signal 425 which cycles amplifying transistor 420 ON / OFF according to an appropriate duty cycle . As a result, amplifying transistor 420 provides an ON / OFF duty cycle of current to heating element 355 which matches the

[0179] MERMAID-0305 PCTfrequency of PMW signal 425, as will be apparent to one of skill in the art in view of the present disclosure . Electrical circuit 390 is electrically connected to heating element 355 via the aforementioned electrical leads 375, 380. Controller 395 operates within a "feedback loop" so as to emit a PMW signal 425 which cycles amplifying transistor 420 ON / OFF at an appropriate frequency to heat heating element 355 (and hence, exterior surface 360 of trocar 320) to the desired temperature for performing a cauterization procedure .

[0180] More particularly, temperature sensor 395, provided in sufficient proximity with heating element 355 so as to provide a temperature signal 430 that reflects the instantaneous temperature of exterior surface 360 of trocar 320, conveys temperature signal 430 is to controller 405 via temperature sensor lead 400. Controller 405 allows the continuous control and automatic adjustment of the temperature of heating element 355 by receiving temperature signal 430 (Fig.

[0181] 15) from temperature sensor 395 and comparing the instantaneous temperature against the desired temperature setpoint (s) (e . g. , as stored in memory of controller 405) . Controller 405 then provides corrective actions to maintain the desired setpoint temperature (i . e . , a predetermined temperature set and stored on memory of controller 405) by emitting a PMW signal 425 to cause either continuously pulsing

[0182] MERMAID-0305 PCTcurrent to be delivered to heating element 355 so as to increase the temperature of heating element 355, or by turning off the pulsing of current to heating element 355 if the setpoint temperature has been reached by heating element 355 (as determined by temperature sensor 395) .

[0183] Apparatus 305 is configured such that activation of heating element 355 can be easily accomplished by the user operating apparatus 305. To that end, in one preferred embodiment of the invention, a push button 432 (Fig. 10A) may be provided on handle 345 so as to facilitate activation of heating element 355 with the push of push button 432. By way of example but not limitation, push button 432 may be provided on a distal, top region of handle 345, or push 432 may be provided on the proximalmost end of handle 345, electrically connected to a circuit between power source 410 (e . g. , a battery pack) and electrical circuit 390 (such that activation of the push button either allows current to flow to electrical circuit 390, and hence to heating element 355, or does not allow current to flow to electrical circuit 390.

[0184] Handle 345 preferably also comprises an indicator (not shown) electrically connected to electrical circuit 390 (or directly to temperature sensor 400) so the user can see the instantaneous temperature of heating element 355 during operation of apparatus 305, whereby

[0185] MERMAID-0305 PCTto know when the heating element 355 is at the desired temperature for cauterization.

[0186] Importantly, by integrating heating element 355 directly into trocar 320, cauterization can be performed immediately following a biopsy procedure . Thus, apparatus 305 completely eliminates additional steps and / or additional cauterizing apparatus needed to complete the biopsy and cauterization procedure .

[0187] If desired, and looking now at Figs . 16, 16A and 16B, power source 410 may comprise external battery pack electrically connected to handle 345 (and hence, to electronics module 385) via an external power lead 433. The provision of power source 410 in the form of an external battery pack provides the same advantages as obtained with cauterizing device 105 discussed above (e . g. , ease of sterilization, ease of disposal, reduced weight of handle 345, etc. ) .

[0188] Looking now at Figs . 17-19, in one exemplary use of apparatus 305, a biopsy procedure is performed (e . g. , to sample a lesion L disposed in a region of healthy tissue R) . The biopsy procedure results in a tissue tract T extending from the point of entry into the soft tissue to the sampled lesion L. Outer cannula 310 and inner cannula 315 are moved proximally so as to expose trocar 320. See Fig. 17.

[0189] Apparatus 305 is then moved distally until trocar 320 (e . g. , sharpened distal tip 325 of trocar 320) contacts the distalmost portion of tissue tract T just

[0190] MERMAID-0305 PCTproximal to lesion L . Heating element 355 is then heated to the desired cauterizing temperature in the manner discussed above . See Fig. 18.

[0191] Finally, apparatus 305 is moved proximally out of tissue tract T when maintaining the desired cauterizing temperature to appropriately cauterize the tissue lining tissue tract T . See Fig. 19. It will be appreciated that as this occurs, controller 405 monitors the instantaneous temperature measured by temperature sensor 395 and appropriately adjusts the duty cycle of a voltage applied to heating element 355 in the manner discussed above so as to maintain proper cauterizing temperature even as different types of tissue (with different heat sink / dif fusion properties) is cauterized.

[0192] It should be appreciated that, if desired, heating element 355 may be provided in the form of a resistive band extending about the perimeter of outer cannula 310. More particularly, and looking now at Fig. 20, with this form of the invention, heating element 355 comprises a band 435 extending about the perimeter of outer cannula 310. Band 435 comprises an electrically-resistive material, i . e . , so as to function as a resistor and emit heat when an electric current is passed through band 435. Band 435 may be formed integral with the sidewall of outer cannula 310 so as to comprise an outer surface 440 flush with the remainder of the sidewall of outer cannula 310. A

[0193] MERMAID-0305 PCTpair of electrical leads 445, 450 extend through lumen 340 of outer cannula 310. If desired, electrical leads 445, 450 may be embedded into the sidewall of outer cannula 310, as will be apparent to one of skill in the art in view of the present disclosure .

[0194] It should also be appreciated that, if desired, heating element 355 may be provided in the form of a resistive band extending about the perimeter of trocar 320. More particularly, and looking now at Fig. 21, with this form of the invention, heating element 355 comprises a band 455 extending about the perimeter of trocar 320. Band 455 comprises an electrically-resistive material, i . e . , so as to function as a resistor and emit heat when an electric current is passed through band 455. Band 455 may be formed integral with the sidewall of trocar 320 so as to comprise an outer surface 460 flush with the remainder of the sidewall of trocar 320. Appropriate electrical leads (not shown) may be provided within central cavity 349 of trocar 320 to conduct electric current to band 455, as will be apparent to one of skill in the art in view of the present disclosure

[0195] Modifications Of The Preferred Embodiments It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the

[0196] MERMAID-0305 PCTnature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.

[0197] MERMAID-0305 PCT

Claims

What Is Claimed Is :

1. Apparatus for cauterizing tissue, said apparatus comprising:a handle;a probe mounted to said handle, said probe comprisin :a distal end, a proximal end, and a lumen extending therebetween, said distal end being characterized by a distal end region that extends a predetermined distance proximally from said distal end;a heating element configured to emit heat so as to heat said distal end region of said probe when an electric current is passed through said heating element ;a temperature sensor configured to measure the instantaneous temperature of said distal end region of said probe, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;a power source;an electronics module comprising:a voltage regulator;a controller; andan amplifying transistor;MERMAID-0305 PCTwherein said power source is electrically connected to said controller and to said amplifying transistor;wherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;wherein said amplifying transistor is electrically connected to said heating element of said probe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; andwherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition.

2. The apparatus of claim 1 wherein said amplifying transistor is cycled between said ON condition and said OFF condition at a predetermined frequency over a predetermined period of time, and further wherein said predetermined frequency comprises a duty cycle of said amplifying transistor .MERMAID-0305 PCT3. The apparatus of claim 2 wherein said duty cycle is a function of said control signal .

4. The apparatus of claim 3 wherein said control signal comprises a Pulse Width Modulation (PWM) signal emitted by said controller.

5. The apparatus of claim 4 wherein said controller comprises a Proportional Integral Derivative (PID) microprocessor controller configured to output said Pulse Width Modulation (PWM) signal .

6. The apparatus of claim 1 wherein said heating element is disposed in said lumen of said probe .

7. The apparatus of claim 1 wherein said electric current comprises Direct Current (DC) .

8. The apparatus of claim 1 wherein said heating element comprises a resistor .

9. The apparatus of claim 1 wherein said temperature sensor comprises one selected from the group consisting of a thermistor, a thermocouple, or a Resistance Temperature Detector (RTD) .MERMAID-0305 PCT10. The apparatus of claim 1 wherein said power source comprises a battery pack, and further wherein said battery pack is contained within said handle .

11. The apparatus of claim 1 wherein said power source comprises a battery pack, and further wherein said battery pack is electrically connected to said handle via an external power lead.

12. The apparatus of claim 1 wherein said distal end region of said probe is formed out of ceramic with an integrated coil within a sidewall of said probe .

13. A method for cauterizing tissue, said method comprisin :providing apparatus for cauterizing tissue, said apparatus comprising:a handle;a probe mounted to said handle, said probe comprising :a distal end, a proximal end, and a lumen extending therebetween, said distal end being characterized by a distal end region that extends a predetermined distance proximally from said distal end;a heating element configured to emit heat so as to heat said distal end region of saidMERMAID-0305 PCTprobe when an electric current is passed through said heating element;a temperature sensor configured to measure the instantaneous temperature of said distal end region of said probe, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;a power source;an electronics module comprising:a voltage regulator;a controller; andan amplifying transistor;wherein said power source is electrically connected to said controller and to said amplifying transistor;wherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;wherein said amplifying transistor is electrically connected to said heating element of said probe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; andMERMAID-0305 PCTwherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition;using said controller to emit a control signal to said amplifying transistor to pass current to said heating element such that said heating element is heated to a predetermined temperature, wherein said control signal cycles said amplifying transistor ON and OFF at a first predetermined frequency;using said controller to monitor the instantaneous temperature of said distal end region of said probe, wherein said instantaneous temperature of said distal end region of said probe comprises the instantaneous temperature of said emitted temperature signal from said temperature sensor;comparing said instantaneous temperature to said predetermined temperature;using a control signal to cycle said amplifying transistor ON and OFF at a second predetermined frequency, wherein said second predetermined frequency is (i) a higher frequency than said first predetermined frequency if said instantaneous temperature is lower than said predetermined temperature, and (ii) a lower frequency than said first predetermined frequency if said instantaneousMERMAID-0305 PCTtemperature is higher than said predetermined temperature .14 . The method of claim 13 wherein said amplifying transistor is cycled between said ON condition and said OFF condition at said first predetermined frequency and said second predetermined frequency over a predetermined period of time, and further wherein said first predetermined frequency and said second predetermined frequency each comprise a duty cycle of said amplifying transistor .

15. The method of claim 14 wherein said duty cycle is a function of said control signal .

16. The method of claim 15 wherein said control signal comprises a Pulse Width Modulation ( PWM) signal emitted by said controller .17 . The method of claim 16 wherein said controller comprises a Proportional Integral Derivative ( PID) microprocessor controller configured to output said Pulse Width Modulation (PWM) signal .18 . The method of claim 13 wherein said heating element is disposed in said lumen of said probe .MERMAID-0305 PCT19. The method of claim 13 wherein said electric current comprises Direct Current (DC) .

20. The method of claim 13 wherein said heating element comprises a resistor.

21. The method of claim 13 wherein said temperature sensor comprises one selected from the group consisting of a thermistor, a thermocouple, or a Resistance Temperature Detector (RTD) .

22. The method of claim 13 wherein said power source comprises a battery pack, and further wherein said battery pack is contained within said handle .

23. The method of claim 13 wherein said power source comprises a battery pack, and further wherein said battery pack is electrically connected to said handle via an external power lead.

24. Apparatus for cauterizing tissue, said apparatus comprising:a handle;an outer cannula comprising a distal end, a proximal end, and a lumen extending therebetween;an inner cannula comprising a distal end, a proximal end, and a lumen extending therebetween, said inner cannula being disposed coaxially within saidMERMAID-0305 PCTlumen of said outer cannula so as to be selectively slidable relative thereto;a trocar comprising a distal end, a proximal end, and a central cavity extending therebetween, said distal end being characterized by a distal end region that extends a predetermined distance proximally from said distal end of said trocar, said trocar being disposed coaxially within said lumen of said inner cannula such that said inner cannula and said outer cannula are selectively slidable relative to said trocar;a heating element, said heating element being configured to emit heat so as to heat said distal end region of said trocar when an electric current is passed through said heating element;a temperature sensor disposed in said central cavity of said trocar, said temperature sensor being configured to measure the instantaneous temperature of said distal end region of said trocar, and to emit a temperature signal reflecting the instantaneous temperature of said distal end region;a power source;an electronics module comprising:a voltage regulator;a controller; andan amplifying transistor;MERMAID-0305 PCTwherein said power source is electrically connected to said controller and to said amplifying transistor;wherein said controller is configured to emit a control signal which is received by said amplifying transistor, whereby to permit said controller to selectively cycle said amplifying transistor between an ON condition and an OFF condition;wherein said amplifying transistor is electrically connected to said heating element of said probe such that current is passed through said heating element when said amplifying transistor is in the ON condition and current is not passed through said heating element when said amplifying transistor is in the OFF condition; andwherein said controller is configured to use said temperature signal emitted by said temperature sensor to determine the frequency at which said amplifying transistor is cycled between said ON condition and said OFF condition.

25. The apparatus of claim 24 wherein said amplifying transistor is cycled between said ON condition and said OFF condition at a predetermined frequency over a predetermined period of time, and further wherein said predetermined frequency comprises a duty cycle of said amplifying transistor .MERMAID-0305 PCT26. The apparatus of claim 25 wherein said duty cycle is a function of said control signal .

27. The apparatus of claim 26 wherein said control signal comprises a Pulse Width Modulation (PWM) signal emitted by said controller.

28. The apparatus of claim 27 wherein said controller comprises a Proportional Integral Derivative (PID) microprocessor controller configured to output said Pulse Width Modulation (PWM) signal .

29. The apparatus of claim 24 wherein said heating element is disposed in said lumen of said probe .

30. The apparatus of claim 24 wherein said electric current comprises Direct Current (DC) .

31. The apparatus of claim 24 wherein said heating element comprises a resistor .

32. The apparatus of claim 24 wherein said temperature sensor comprises one selected from the group consisting of a thermistor, a thermocouple, or a Resistance Temperature Detector (RTD) .MERMAID-0305 PCT33. The apparatus of claim 24 wherein said power source comprises a battery pack, and further wherein said battery pack is contained within said handle .

34. The apparatus of claim 24 wherein said power source comprises a battery pack, and further wherein said battery pack is electrically connected to said handle via an external power lead.MERMAID-0305 PCT

Images