Abstract:
A portable, thermal cauterizing forceps device for use in surgery. The device incorporates a pair of ceramic heater elements mounted within the tips of the tines of a forceps. The forceps is used to grasp tissue or blood vessels and apply heat to effect cauterization. In the case of the first embodiment of the invention, the forceps instrument incorporates a battery and control electronics. The thermal-forceps is of a self-contained wireless, handheld disposable design. In a second embodiment of the invention, the forceps handpiece is connected to an external power source. Both embodiments of the forceps incorporate set of rapidly heating ceramic heater elements that may be composed of silicon nitride. An LED provides the operator feedback as to the operating level of the heaters and/or battery reserve. Enhancements to the second embodiment include a rechargeable power supply, variable control of the heater temperature, as well as a, digital display of the tip temperature.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a handheld, portable thermal-cauterizing forceps including an integrated thermal heating surface disposed at each tip. 
     There are many surgical cautery devices available for the surgeon to ablate and vaporize tissue. Hot knives and cutting coagulators have been used to make skin incisions. The cautery can also be used in surgery to aid in hemostasis or control bleeding by coagulating blood vessels. Employing various cautery modalities decreases the duration of some surgical procedures by providing the surgeon a rapid method of coagulation without the need for suture ligation of blood vessels encountered during dissection. 
     Typically, surgical cautery is accomplished by directing a heating process onto tissue. The heat may be generated by either a thermal or electro-surgical process. Most commonly, an electro-surgical process using a radio frequency (RF) is used. The RF units generate heat by using high frequency electrical current and the resistive nature of tissue to produce heat. This technique requires a bulky generator and heavy electrical components to operate. Typically, RF electrocautery units require a power lead cable to the electro-surgical hand instrument and a large surface area grounding pad. More often than not, radio frequency surgical units are bulky expensive units which require a cable connection. Employing RF cauterization in a surgical operation may add significant cost to the procedure because the grounding pad, cable and handpiece must all be either re-sterilized or replaced in the case of disposable use. 
     A less common method of generating heat for coagulation of tissue is by thermal cautery. Thermal cautery is achieved by electrical heating of a resistive-wire loop or resistive electronic part by applying an electrical voltage. The prior art describes many handheld disposable, hot-wire loop cautery instruments. These devices have severe limitations as to their scope of use in surgery. The heat generated by the handheld battery powered devices is very small with a low heat capacity. The available patented devices are effective for cauterization of only the smallest of blood vessels, such as, vessels in the sclera of the eye. These battery powered hot-wire cautery instruments are not effective for use in cauterization of larger blood vessels encountered in most surgical procedures. A technique employing the electrical over driving of a zener diodes to produce heat has also been described in several patents. This device is primarily for limited endoscopic applications. 
     SUMMARY OF THE INVENTION 
     In order to overcome the limitations and disadvantages of the prior art, the present invention provides, in an embodiment, a new and improved hand-held, high energy, portable thermal cautery forceps. More particularly, the new and improved surgical forceps instrument includes an enclosure which houses a battery and electronic control. Active ceramic heaters are provided on the two tips of the operative end of the forceps. In a second embodiment, the thermal forceps may alternatively be powered by an external power source. 
     The new thermo-cautery forceps device in accordance with an embodiment of the invention provides the surgeon with several significant improvements in the state of the art. A first benefit of the thermal-cautery forceps is that it is cordless and fully portable. In the first embodiment of the invention, no cables or external power supply is necessary. This keeps the operative field clear of wires and cables. The thermal cautery of this invention does not require any grounding pad or foot switches. 
     A second benefit is the very high heating capacity of the thermal elements of the device. Temperatures of over 1000° C. are easily obtainable. A preferred tip operating range is from 650° to 700° C. This heat capacity and temperature can easily cauterize medium and large blood vessels. 
     A third benefit provided by the new and improved thermal cautery forceps of the invention is its ability to heat to operating temperature in a very short time period, for example, within about one second. The preferred embodiment uses silicon nitride, ceramic heater elements. These new ceramic heaters exhibit rapid heating and cooling characteristics. Silicon nitride ceramic heaters have been used successfully in other fields outside surgery. To the inventor&#39;s knowledge, this is believed to be the first use within the field of surgical thermal coagulation. 
     In an alternative embodiment, less expensive alumina heaters and ceramic resistors or diodes may be employed in substitution for the silicon nitride ceramic heater elements to provide cost savings. However, such alternative types of heaters may be less preferred because longer times to obtain operating temperatures may be required. 
     In an embodiment, the preferred power source is a battery rendering the device completely portable. Four lithium metal 3 volt batteries can be utilized as well as dual 9 volt batteries, one for each tine. One preferred battery is TADIRAN® which provide 11.5 volts and are rechargeable. A 12 volt direct current power supply can be utilized as well with a connecting cord or cable. 
     A fourth advantage provided by the new and improved forceps is the placement of the thermal cautery heater elements at the ends of forceps tines. The unique position of the ceramic heater elements allows tissue and blood vessels to be easily grasped and directly coagulated in a controlled manner. The application of a closing or gripping pressure of the forceps against the tissue or vessel enhances the effectiveness of the coagulation. 
     A fifth benefit of the forceps device in accordance with the invention is to decrease the cost and enhance the availability of surgical cautery. The first embodiment of the thermal forceps allows for the device to be packaged as a sterile disposable instrument. The instrument can be used in emergency or field operations. The device may be used for hemostasis during outpatient surgical procedures in clinics and in surgery centers, as well as, at emergency scenes 
     Other objects and advantages provided by the present invention will become apparent from the following Detailed Description taken in conjunction with the Drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the new and improved thermal cautery forceps instrument of the present invention in accordance with a first embodiment including an internal battery; 
     FIG. 2 is a top plan view of the new and improved thermal cautery forceps shown in FIG. 1; 
     FIG. 3 is an end elevational view of the new and improved thermal cautery forceps showing the front or forceps tines end; 
     FIG. 4 is an end elevational view of the new and improved thermal cautery forceps viewed from the rear or opposite end of the forceps; 
     FIG. 5 is an elevated cross-sectional view of the new and improved thermal cautery forceps shown in FIGS. 1-4, showing the logic controller board, LED indicator lamp, internal switch and internal battery; 
     FIG. 6 is a schematic block diagram of the electrical circuit for the new and improved thermal cautery forceps of the first embodiment of the invention comprising a battery powered portable device; 
     FIG. 7 is an elevated side view of the thermal cautery forceps instrument in accordance with a second embodiment of the invention including an external power supply unit; 
     FIG. 8 is a top plan view of the new and improved thermal cautery forceps shown in FIG. 7; 
     FIG. 9 is an elevated end view of the new and improved thermal cautery forceps of FIG. 7 taken from the forceps tine end; 
     FIG. 10 is an elevated end view of the new and improved thermal cautery forceps shown in FIG. 7, taken from the opposite end and showing the cable connector; 
     FIG. 11 is an elevated cross-sectional view of the new and improved thermal cautery forceps in accordance with the second embodiment, showing the housing and cable connection to the pair of heater units; 
     FIG. 12 is an elevated front view of the external power supply unit for use with the new and improved thermal cautery forceps in accordance with the second embodiment showing control features, including a power switch, audio speaker, temperature display, SET/READ switch, temperature control knob, recharging lamp and ready LED lamp; 
     FIG. 13 is a perspective view of a holster for carrying a portable thermal cautery forceps made in accordance with the present invention; and 
     FIG. 14 is a side elevational view of the holster shown in FIG.  13 . 
    
    
     From the above description it is apparent that the objects of the present invention have been achieved. While only certain embodiments have been set forth, alternative embodiments and various modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of the present invention. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In accordance with a preferred embodiment of the invention, a new and improved thermocautery surgical forceps comprises a surgical forceps body including a pair of elongate tine members extending from the forceps body to respective free end tip portions spaced from the forceps body. The tine members are mounted to the forceps body in a manner providing resilient compressible movement of the tine members between a normally open position, wherein the tines are disposed in aligned, parallel, spaced-apart relationship, and a squeezed closed position, wherein the tip portions of the tine members are disposed in confronting abutting relationship. Each tine member includes a tissue contact surface  18 ′,  19 ′ defined on an inner facing surface of the tine member adjacent the tip portion. A ceramic heater element is disposed in each tine member so as to effectively heat the tissue contact surface to an elevated tissue cauterizing temperature. The ceramic heater elements are optionally connected to a power source. The tine members may be squeezed together to their squeezed closed position to grippingly, squeezably engage tissue to be cauterized between the tip portions. The tissue contact surfaces on the tines may be heated to a tissue cauterizing temperature to effectively thermocauterize the gripped tissue. 
     Referring now to FIGS. 1-6, a preferred embodiment of the new and improved thermocautery surgical forceps generally designated by reference numeral  10  is shown. Forceps  10  includes a forceps body or housing  12  for the battery  14  (see FIG. 5) and electrical control components  16 . Specialized ceramic heating elements  18 ,  19  are disposed on the tips  20 ,  21  of the forceps tines  22 ,  24 . FIGS. 1-6 relate to the first embodiment of the invention, that of a portable unit  10  with an internal battery supply  14 . FIGS. 7-11 relate to the second embodiment of the invention, that of a cautery unit  26  configured as a thermal forceps  28  with an external power supply (not shown). 
     As shown in FIG. 1, the first embodiment of the cauterizing instrument  10  generally comprises a housing  12  and an integrated forceps tines assembly  32 . The housing  12  encloses the battery  14  (see FIG.  5 ), and a number of electrical control components  16 , such as controller electronics  34 , an LED  36  and an internal power switch  38 . The forceps tines  22 ,  24  of the instrument, as shown in FIG. 1, exit from openings in the front end of the housing  12 . The forceps assembly comprises two tines  22 ,  24  of equal length. Each tine  22 ,  24  is constructed of a heater-carrier  40 ,  41  and an insulator cover-piece  42 ,  43 . The heater-carriers  40 ,  41  comprise a metal arm  44 ,  45  that supports an attached ceramic heater unit  46 ,  47 . Each insulator cover-piece  42 ,  43  is a shroud  48 ,  49  that covers the heater  46 ,  47  and its carrier arm  44 ,  45 . Each shroud cover  48 ,  49  is heat resistant and protects the surgeon&#39;s fingers from the heat generated by the ceramic heaters  46 ,  47 . Each shroud  48 ,  49  includes a recess  50 ,  51  to fit the operators thumb and index finger to aid in holding the instrument. Inward compression on the shrouds  48 ,  49  act to compress the heater carrier arms  44 ,  45  and will cause the switch  38  (see FIG. 5) to close. 
     FIG. 2 shows a top view of the instruments with the LED  36  exiting the rear of the housing enclosure and the forceps shroud cover with finger recess The enclosure is rectangular in shape having a closed end and an open end The open end allows the forceps assembly to exit from the enclosure. The enclosure is composed of a plastic formed with an injection process. The open end of the enclosure is shown in FIG.  3 . The forceps are shown as well as the LED  36  on the top of the housing. The position of the LED  36  allows the surgeon easily visualize the operation of the instrument. The surgeon can see the LED  36  while it is held in the hand and operated. FIG. 4 shows the closed end of the housing. 
     Shown in FIG. 5 is a cross-sectional view of the enclosure containing a battery  14  for power supply. The battery may be rated form 3 volts to 24 VDC depending on the heating characteristics required. The battery  14  may be of an alkaline or lithium cell. In addition, two 9 volt batteries may be used, one for each tine  22 ,  24 . Lithium metal batteries may also be utilized. One preferred battery is sold under the trademark TADIRAN®. The battery positive and negative terminals  54 ,  56  are connected to the instrument circuitry by a terminal battery clip. Also, contained within the enclosure is a small circuit board  34  that is populated with an integrated circuit and support components. The circuit board  34  has connections to the power supply  14 , LED  36 , heater elements  118 ,  19  and switch mechanism  38 . This circuit board  34  acts as a logic-controller to regulate the current delivered to the heating elements. The logic-controller circuit monitors the temperature and resistance of the heater elements  18 ,  19  and regulates the voltage supply. At the onset of operation the logic circuit allows high current to flow to the heaters  18 ,  19  aiding in initial rapid heating. The current is then reduced to maintain the heaters  18 ,  19  at a set temperature. The controller circuit logic also controls the LED  36  to indicate the operative state of the heater elements  18 ,  19 . The LED  36  will illuminate only if the battery power reserve or supply voltage attain a specified level and heaters reach the preset operational temperature. The logic controller also measures the internal resistance and temperature of the heater elements  18 ,  19 . The LED  36  will fail to illuminate if these values fall outside the normal operational limits. 
     In an alternative design of the first embodiment a small piezo-electric speaker may be incorporated into the forceps enclosure. In the alternative design (not shown) the logic controller is further able to supply a piezo-electric speaker with supply voltage. The piezo-electric speaker provides the operator with auditory feedback pertaining to the operation of the instrument. The speaker emits a sound to give the surgeon an audio feedback as to the operation of the instrument. The sound indicates that the heating elements  18 ,  19  are at the normal operative temperature for effective cauterization. 
     Also shown in FIG. 5, is the mounting arrangement of the forceps tines  22 ,  24 . Each tine  22 ,  24  is mounted on opposite sides of a rectangular neoprene spacer  52 . The pair of tines  22 ,  24  and neoprene spacer  52  are fasted together by a binding pin  54  with end caps. The off-center arrangement fastening of the tines  22 ,  24  to the neoprene spacer  52  allows for a spring like tweezer effect. 
     An electrical open/close single pole switch  38  is incorporated into the instrument. The switch  38  is positioned within the housing enclosure  12  between the base of the forceps tines  22 ,  24 . The switch  38  is composed of two contacts  58 ,  60  that are brought into contact when the forceps  10  are squeezed together. Closing the switch  38  allows current to be delivered to the heaters. The contacts  58 ,  60  meet, as soon as, closure of the tines  22 ,  24  is begun and stays in a closed position as long as the tines  22 ,  24  are closed. Release of the forceps tines  22 ,  24  will open the switch  38  and current supply to the heaters  46 ,  47  will terminate. 
     The typical wiring diagram and schematic is shown in FIG.  6 . The schematic shows a DC battery  14  with positive and negative leads  54 ,  56  connected to the logic control circuit board  34 . The circuit board  34  is able to regulate the current delivered to the heater elements  46 ,  47  by measuring the internal electrical resistance of the heaters  46 ,  47  and the voltage available from the battery  14 . The controller also will vary the initial resistance of the heater circuit to obtain quick heat up at power on. The controller logic also controls the illumination of the LED  36 . The LED  36  is illuminated when a preset temperature of the heaters  46 ,  47  is reached. The ON/OFF switch  38  incorporated into the forceps  10  is also depicted. The switch  38  that is closed upon closure of the forceps  10  allows current to flow to the heaters  46 ,  47 . Two heaters  46 ,  47  are shown which are wired in parallel. The internal resistance of the two heaters  46 ,  47  is about 5 to 10 ohms, preferably about 8 ohms, or 4 ohms per heater  46 ,  47 . The typical heater  46 ,  47  is composed of either alumina of silicon nitride or similar glass or ceramic material. This material specification is used due to high wattage density, rapid heat increase to 1000 degrees within one second, high level of insulation and non-stick nature of the ceramic to charred tissue. The preferred tip operating temperature range is 650 to 700° F. The second embodiment  26  of the invention is shown in FIGS. 7-12. In this embodiment an external power source is used to power and control a simple thermal cautery forceps. The forceps  26  in this embodiment is either of an inexpensive disposable or a more durable reusable design. FIGS. 7,  8 ,  10  and  11  show the externally powered cautery forceps  28 . FIG. 7 is a side elevational view of the thermal cautery forceps  28  instrument of the second embodiment of the invention. A cable  72  connects the forceps to the external power supply unit (not shown). Each tine  74 ,  76  is composed of a rigid metal carrier with ceramic heater  78 ,  80  and an insulating plastic shroud  82 ,  84 . FIG. 8 is a top plan view thereof; FIG. 9 is an end elevational view there of illustrating the forceps tine end. FIG. 10 is an end elevational view of the end opposite the forceps illustrating the cable connector  86 . FIG. 11 is a cross-sectional view of the second embodiment of the present invention, showing the housing  88  and cable connection. A pair of wires  90 ,  92  connects the cable  72  to the pair of thermal heater elements  78 ,  80  wired in parallel. Also shown in FIG. 11 is the neoprene spacer  94 . The spacer  94  is positioned between the forceps tines  74 ,  76 . An off center-binding pin  96  extends through the tines  74 ,  76  and the spacer  94  provides a spring effect. The spring effect also activates the ON/OFF switch  98 . The switch  98  is composed of two electrical metal contacts  100 ,  102  affixed to the inside of each forceps tine  74 ,  76 . 
     FIG. 12 is a front elevation of the external power supply unit  103 . This unit  103  contains a power switch  104 , audio speaker  106 , digital temperature display  108 , SET/READ switch  110 , temperature control knob  112 , recharging indicator lamp  114  and ready LED lamp  116 . The power supply unit  103  may be a 12 volt DC unit. 
     As shown in FIG. 12, the cable  72  connected to the forceps  26  enters the power unit  103 . The power switch  104  is located on the front panel  118  that illuminates when switch  104  is on. The speaker  106  signals the surgeon of proper heater element temperature for cauterization. The speaker  106  will sound when the instrument reaches the SET temperature after the forceps are squeezed together to initiate heating. The output of the speaker  106  is vented outside the power unit through a small port shown in FIG.  12 . The unit also contains a temperature control. The temperature may be varied by positioning the SET/READ switch  110  to the SET position and rotating the temperature adjust knob  112  to the desired temperature. The digital temperature display  108  reports the desired set temperature in degrees fahrenheit. The temperature adjust control  112  may either be of an analogue or digital type. This control allows the surgeon to select a temperature for a desired effect depending on the thickness and moisture content of the tissue to be cauterized. The digital temperature display  108  may indicate the actual temperature of the ceramic heater elements  78 ,  80  when the SET/READ switch  110  is positioned in the READ position. The LED indicator  114  is incorporated into the power supply, which is illuminated when the batteries are recharging. The Heater On Indicator  116  is incorparated into the power supply, which is illuminated when the heater elements are heated. This occurs whenever the power unit is connected to a  110  VAC line. A charging circuit (not shown) regulates the recharging process. 
     FIGS. 13 and 14 illustrate a holster  130  for accommodating the forceps  10  or  26 . A cavity  132  receives the tine end of the forceps  10  or  26 . A loop  134  or slits  136 ,  138  may be provided for attaching the holster  130  to a belt  140 . 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. Further, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modification commensurate with the above teachings, and the skill or knowledge in the relevant art, are within the scope of the present invention. The embodiments described herein above are further intended to explain modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other embodiments and with various modification required by their particular applications or uses of the invention. It is intended that the appended claim be construed to include alternative embodiments to the extent permitted by the prior art.