Abstract:
A surgical instrument for removal of a conical section the cervix for pathological examination is disclosed. The device includes a circular knife having a plurality of double-edged blades, the edges of adjacent blades enclosing against one another when the device is operated from unengaged to engaged positions. A hollow plunger is further disclosed used to actuate the circular knife. Novel pivot devices are additionally included to provide translational movement of the hollow plunger bar. A pronged stabilization rod is disclosed to prevent the circular knife from moving away from the target tissue during a cutting stroke. The device is an improvement over prior devices and procedures in that it provides a precision conical tissue sample ideal for analysis with minimal resulting bleeding.

Description:
[0001]     This application claims the benefit of provisional patent application No. 60/525,556, filed on Nov. 25, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention pertains generally to medical instruments. More particularly, the present invention relates to surgical instruments for performing a uterine cervical conization. The present invention is particularly, but not exclusively, useful as a surgical instrument for removal of a conical section of cervical tissue for a biopsy.  
         [0004]     2. Description of the Prior Art  
         [0005]     Conization of the cervix, or “cone” biopsies are known for diagnosis, prevention, and treatment for cancer of the uterine cervix. Such cervical cancer usually progresses slowly over an extended period from the first appearance of pre-cancerous abnormalities. With today&#39;s sophisticated screening programs involving regular uterine pap smear tests, colposcopy and other procedures, it is increasingly likely to detect certain abnormalities in their early stages and successfully treat these patients and preserve reproductive functions. Precancerous, abnormal cells present on cervical tissue is a condition known as dysplasia or cervical intraepithelial neoplasia (CIN).  
         [0006]     Cervical conization is a procedure performed to remove abnormal tissue from the cervix to further diagnose cancer and to better understand results of a pap smear and/or colposcopy. The procedure may further be used to treat chronic cervicitis (inflammation of the cervix) and it is sometime called a “cone” biopsy because a cone-shaped wedge of tissue is removed from the cervix and examined under a microscope. The cervix is located in the lower part of the uterus that is high in the cervical canal, making access relatively difficult, wherein the uterus is the muscular organ at the top of the vagina where menstruation begins and babies gestate.  
         [0007]     Technological developments have introduced a wide variety of surgical procedures for conization of the cervix. Among them are the traditional cold scalpel procedure, punch biopsy, and loop electrosurgical excision procedure (LEEP). The electrosurgical procedure, in particular, is problematic in that a fragmented sample may be obtained that does not have a “cone shape” as is desired for pathologic examination. Also, any lateral movement of the loop device may be damaging to the lateral vaginal wall.  
         [0008]     Additionally in the art are manual tool-based procedures such as the punch biopsy. Exemplary devices in the prior art are essentially modified biopsy forceps in that they hinge about a pivot point and close around the target tissue. These devices generally require excessive “sawing,” “grabbing,” or rotational cutting that may damage tissue more excessively than desired and produce a relatively high amount of bleeding adding complications. Further, as with the LEEP procedure, the quality of the sample and the resulting bleeding is highly dependent upon the skill and experience of the surgeon and may require the surgeon to estimate the distance and angle of the cut.  
         [0009]     Accordingly, it is an object of present invention to provide a medical device for performing uterine cervical conization that yields high quality tissue samples for analysis with a minimum degree of surgical skill and estimation. It is further an object of the present invention to provide a surgical instrument for excising a tissue sample that results in a minimum amount of bleeding. Additional objects and advantages of the present invention will be apparent from the following invention summary and description.  
         [0010]     The invention may also be regarded as a surgical instrument for excising a tissue sample from a tissue mass, the surgical instrument comprising: a stabilization rod having a distal and a proximal end and defining a longitudinal axis; a hollow plunger bar disposed about the stabilization rod having a distal and proximal end; a circular knife having a plurality of blades converging on a point of convergence, the circular knife disposed about the distal end of the hollow plunger bar, the circular knife further having engaged and unengaged positions; and a housing having a distal portion accommodating the circular knife, the housing distal portion having an annulus tapered at an end thereof, the tapered annulus directing the circular knife toward the point of convergence.  
         [0011]     Lastly, the invention may be regarded as a surgical instrument for excising a tissue sample from a tissue mass, the surgical instrument comprising: a hollow plunger bar disposed about the stabilization rod having a distal and proximal end; and a circular pentagonal knife having five blades converging on a point of convergence, the circular knife disposed about the distal end of the hollow plunger bar, the circular knife further having engaged and unengaged positions.  
       BRIEF SUMMARY OF THE INVENTION  
       [0012]     The present invention specifically addresses and alleviates the above mentioned deficiencies associated with the prior art. More particularly, the present invention, in a preferred embodiment is, a surgical instrument for excising a tissue sample from a tissue mass, the surgical instrument comprising: a hollow plunger bar defining a longitudinal axis having a distal and proximal end; a circular knife having a plurality of blades converging on a point of convergence, the circular knife disposed about the distal end of the hollow plunger bar, the circular knife further having engaged and unengaged positions; and a housing having a distal portion accommodating the circular knife, the housing distal portion having an annulus tapered at an end thereof, the tapered annulus directing the circular knife toward the point of convergence.  
         [0013]     While the apparatus and method has or will be described for the sake of grammatical fluidity with functional explanations, it is to be expressly understood that the claims, unless expressly formulated under 35 USC §112, are not to be construed as necessarily limited in any way by the construction of “means” or “steps” limitations, but are to be accorded the full scope of the meaning and equivalents of the definition provided by the claims under the judicial doctrine of equivalents, and in the case where the claims are expressly formulated under 35 USC §112 are to be accorded full statutory equivalents under 35 USC §112. The invention can be better visualized by turning now to the following drawings wherein like elements are referenced by like numerals.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:  
         [0015]      FIG. 1A  is a perspective view of a cervical conization device incorporating the presently preferred embodiment of the present invention;  
         [0016]      FIG. 1B  is a perspective view of the illustration in  FIG. 1A  with major portions of the device housing cut away;  
         [0017]      FIGS. 2A and 2B  illustrate cross-sectional views of the preferred embodiment of the present invention taken along sectional line  2 - 2  in  FIG. 1A ;  
         [0018]      FIGS. 3A through 3C  illustrate a preferred stabilization rod of the present invention inner and outer sleeves;  
         [0019]      FIGS. 4A through 4C  are side and top plane views of a hollow plunger of the present invention;  
         [0020]      FIG. 5 . is an end view of the presently preferred embodiment of the present invention;  
         [0021]      FIGS. 6A and 6B  illustrate a preferred circular knife of the present invention;  
         [0022]      FIG. 6C  illustrates a flat cut-out of the preferred circular knife of the present invention;  
         [0023]      FIG. 7  is a cross-sectional view of a second preferred embodiment that uses a tri-blade system where the blades  18   a  move radially in and out within corresponding guide notches in an annulus  52 ′;  
         [0024]      FIG. 8A  is an exploded perspective view of a portion of the second preferred embodiment shown in  FIG. 7 , showing how a guide tab  118  on the bottom of one of the three blades  18   a ′ engages the guide notch  152  in the annulus  52 ′, a spring  153  being present to bias the blade  18   a ′ outward;  
         [0025]      FIG. 8B  shows the position of the three blades  18   a ′ when the annulus  52 ′ in the assembly suggested by  FIGS. 7 and 8 A is moved forward and the blades are converged;  
         [0026]      FIG. 9A  is a perspective view of the second preferred blade assembly  18 ′;  
         [0027]      FIG. 9B  is an end view of the second preferred blade assembly  18 ′; and  
         [0028]      FIG. 9C  is a perspective view of the second preferred blade assembly with resistive pads  161 , conductors  162 , and a wire bundle  163  for implementing an electro-cauterization process on the exterior of the second preferred blade assembly  18 ′.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]     Referring initially to  FIG. 1A , a perspective view of a preferred embodiment of a cervical conization device is illustrated and generally designated  10 . As shown, device  10  has a housing having a distal portion  12  that houses a plurality of substantially pentagonal blades  18   a  ( FIG. 6C ) that collectively form a circular knife  18  of the present invention. The housing further has an elongated sleeve portion  14  that houses the actuating devices of the invention as discussed herein in further detail. A housing stationary handle portion  16  is opposite a trigger handle  24  and is generally perpendicular to the housing elongated sleeve portion  14  of device  10 . As further described herein, blades  18   a  ( FIG. 6C ) precisely converge on a point  15  just beyond a plurality of barbs  22  of a barbed stabilization rod  20  of the present invention. Whereas exemplary prior art devices converge on a pin, by comparison, the present invention converges past the stabilization rod  20  and therefore is enveloped (as shown in  FIG. 2B ) and ensures a cleaner cut.  
         [0030]     Referring to  FIG. 1B , a perspective view of the illustration in  FIG. 1A  is shown with portions of the housing drawn in transparency to show the actuating devices of the present invention. Hollow plunger  30  is employed to provide translational movement of the circular knife  18 . As shown, the circular knife  18  is a circular pentagonal knife  18  in the preferred embodiment. The translational movement is provided by first squeezing trigger handle  24  to cause rotational movement  25  of Y-shaped swing arm  28  about fulcrum pin  26 . A first pivot device  32  in conjunction with second pivot device  34  is provided to convert rotational movement  25  to translational movement of the hollow plunger bar  30 . A tee portion  31  of hollow plunger bar  30  has first and second ends and is provided to connect to the second pivot device  34 , first and second pins  34   a ,  34   b  to middle segments  35 . Further, middle segments  35  are connected to Y-shaped plunger bar  28  via first pivot device  32  first and second pins  32   a ,  32   b . Stabilization rod  20  is illustrated having barbs  22  on a distal end with respect to an instrument  10  user (doctor). Proximally, stabilization rod  20  has a seat  36  to secure the stabilization rod  20  against a housing rear inside wall  17 , as further illustrated in  FIGS. 2A and 2B .  
         [0031]      FIGS. 2A and 2B  illustrate cross-sectional side views of the preferred embodiment of the present invention taken along sectional line  2 - 2  in  FIG. 1A  showing instrument  10  in an unengaged and engaged positions. The presently preferred cervical conization device  10  is initially shown in the unengaged position in  FIG. 2A . Circular knife  18  is housed within the housing distal portion  12 . The pentagonal knife blades  18   a  ( FIG. 6C ) surrounds a harpoon-like, barbed rod  20  that will ultimately attach to the patient&#39;s cervical tissue. In other words, the unengaged tool of  FIG. 2A  is inserted into the patient&#39;s vagina until the barbed  22  rod  20  pierces the tissue of a patient&#39;s cervix. Subsequently, the doctor squeezes the trigger handle  24  of the device  10  so that the blades  18   a  move to the engaged position of  FIG. 2B . Note that the circular knife  18  is mounted to an end having an annulus  52  ( FIG. 4A ) of a hollow plunger bar  30  that slides back and forth, translationally with respect to a longitudinal axis  11  (see  FIG. 2B ). The hollow plunger  30  further slides back and forth along the barbed stabilization rod  20  when the handle  24  is opened and closed. As the handle  24  is squeezed, the hollow plunger  30  and pentagonal blades  18   a  carried in the annulus  52  connected to the hollow plunger  30  are pushed forward, out of the distal end of the device  10 . Due to the angled or tapered annular shoulder  13  at the interior of the tool&#39;s housing distal portion  12 , and further due to the geometry of the pentagonal blades  18   a , the blades  18   a  are converged towards one another as they move outward in order to slice out a cone of biopsy tissue. The barbed  22  stabilization rod  20  prevents the cervical tissue from moving away as the blades  18   a  move outward from the device&#39;s  10  tapered annulus  13  and converge toward point  15 . Once the blades  18   a  are fully converged, the doctor removes the device  10  from the patient along with the cervical cone biopsy sample. The doctor then disengages the device  10  and removes the biopsy tissue from the device for pathological examination.  
         [0032]      FIGS. 3A through 3C  illustrate a preferred stabilization rod  20  of the present invention. In the embodiment shown, the stabilization rod  20  is comprised of an inner rod  42  and an outer sleeve  20 . In the preferred embodiment, inner sleeve  42  is approximately 2 mm in diameter and outer sleeve  20  is approximately 3 mm in diameter, so that the rod  42  may move axially forward within the sleeve  43  against the bias of a spring  48  when knob  46  is depressed by the user&#39;s thumb. Outer sleeve  20  has the annular seat  36  that rests against the rear inside wall  17 , discussed herein, and the annular seat  36  is opposed by nut  44  on the opposite side of the rear inside wall  17  ( FIG. 2B ). Nut  44  provides a means to adjust stabilization rod  20  with respect to device  10  before use. Inner rod  42  has a knob  46  at a proximal end that further provides means to adjust the position of the inner rod  42  and its flexible prongs  22  within the outer sleeve  43 .  
         [0033]      FIGS. 4A through 4C  are side and top plan views of the hollow plunger  30  of the present invention further illustrating stabilization bar  20  with its barbs  22  threaded therethrough. The hollow plunger  30  has an annulus  52  for carrying the circular knife  18  according to a preferred embodiment of the invention. In a preferred embodiment, stabilization rod  20  has a diameter of approximately 3 mm while hollow plunger  30  has a diameter of approximately 5 mm so that the hollow plunger  30  may slide axially over the stabilization rod  20 .  FIG. 5  further illustrates an end view of the presently preferred embodiment of the present invention, illustrating the first and second pivot devices  32 ,  34 .  
         [0034]     Referring to  FIGS. 6A through 6C  a preferred circular pentagonal knife  18  of the present invention is further illustrated. Each blade  18   a  is doubled-edged  62  and converges against adjacent blades  18   a  during a cutting engagement to provide a clean cut. Radii r 1  and r 2  are constant to provide convergence upon a single point  15 . In a preferred embodiment, r 1  is approximately equal to 1.5 cm and r 2  is approximately equal to 3.08 cm. Also according to the invention, r 2 , the radius of the annulus  52 , is selected according to the diameter of the cut desired. Similarly, the width dimensions w 1 , w 2 , w 3 , w 4 , particularly, w 3  precisely determine the depth of a tissue sample as surgical precision is a specific advantage of the present invention. It is further contemplated that the knife  18  of the invention is configured to be easily replaceable and disposable. In a preferred embodiment, w 1 , w 2 , w 3 , w 4 , are 10 mm, 4 mm, 19 mm and 33 mm, respectively. The diameter and depth of a particular tissue sample with vary with a particular patient is needed and may also depended on the size of any abnormality or lesion of interest.  
         [0035]     Referring to  FIG. 6C , a flat cut-out of circular knife  18  illustrated. Knife  18  may be stamped out of thin metal material known in the art and also has rectangular cut-outs  64  adjacent to an annulus width portion  66 . The rectangular cut-outs  64  assist in enfolding the metal material about the annulus  52 .  
         [0036]      FIG. 7  is a cross-sectional view of a cervical conization device  10 ′ according to a second preferred embodiment of the invention. Here, the device  10 ! uses a tri-blade system where the three blades  18   a ′ move radially in and out within corresponding guide notches in an annulus  52 ′. As shown, the second preferred device  10 ′ features a distal portion  12 ′ that has been radially expanded relative to the first embodiment. The expanded geometry of the distal portion  12 ′ accommodates the radial movement of the blades  18   a ′ when the annulus  52 ′ is in a retracted position.  
         [0037]     The operation of the second preferred cervical conization device  10 ′ is best understood with reference to  FIGS. 8A and 8B .  FIG. 8A , in particular, is an exploded perspective view of a portion of the second preferred embodiment shown in  FIG. 7 , showing how a guide tab  118  on the bottom of one of the three blades  18   a ′ engages the guide notch  152  in the annulus  52 ′, a spring  153  being present to bias the blade  18   a ′ outward.  FIG. 8B  shows the position of all three blades  18   a ′ when the annulus  52 ′ in the assembly suggested by  FIGS. 7 and 8 A is moved forward and the blades are converged by the geometry of the distal portion  12 ′ (see  FIG. 7 ).  
         [0038]      FIG. 9A  is a perspective view of the second preferred blade assembly  18 ′ and  FIG. 9B  is an end view of the second preferred blade assembly  18 ′. As shown, the blades  18   a ′ are only curved about the long axis. The guide tabs  152  are mounted in a suitable fashion to a base (not separate numbered) of each blade  18   a ′ . The guide tabs  152  are made of a rigid, low friction material such as Teflon or UHMW plastic.  
         [0039]     It is believed that this second preferred cervical conization device  10 ′ will provided the added benefit of preventing the blades from bending or “troughing”, and failing to converge on a common point, when deployed into the patient&#39;s tissue.  
         [0040]      FIG. 9C  is a perspective view of the second preferred blade assembly  18 ′ with resistive pads  161 , conductors  162 , and a wire bundle  163  for implementing an electro-cauterization process on the exterior of the second preferred blade assembly  18 ′. The wire bundle  163 , of course, leads to a suitable cautering device that drives current through the resistive pads  161  and creates sufficient heat to cauterize the biopsy bed, i.e. the tissue adjacent to the biopsy site. Because it is desirable to avoid cauterizing the biopsy tissue itself, the interior of the blades  18   a  should be coated with a suitable material that provides sufficient thermal insulation.  
         [0041]     Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example and that it should not be taken as limiting the invention as defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the invention includes other combinations of fewer, more or different elements, which are disclosed in above even when not initially claimed in such combinations.  
         [0042]     While the particular Cervical Conization Device as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.  
         [0043]     Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalently within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements.