WO1997005826A1

WO1997005826A1 - System for extracting tissue samples in laparoscopy

Info

Publication number: WO1997005826A1
Application number: PCT/US1996/013572
Authority: WO
Inventors: Gary Long
Original assignee: Laser Centers Of America
Priority date: 1995-08-08
Filing date: 1996-08-07
Publication date: 1997-02-20
Also published as: AU6956396A

Abstract

A system for extracting tissue samples during laparoscopic surgery on a patient includes a conventional cannula and a device sealingly insertable therein so as to extend from a distal internally-deployed end of the cannula a plurality of stiff elastic flexible bristles. Using another cannula to light and obtain visual imaging of the surgical site, the user selects incised tissue which is to be extraced and by pressing distal ends of the bristles to the selected tissue positively engages them to the selected tissue. The device is then retracted from the cannula. The tissue-engaging distal portion thereof, including the bristles, is detached and is placed into a container so that the tissue is sealed therein.

Description

SYSTEM FOR EXTRACTING TISSUE SAMPLES IN LAPAROSCOPY

Field of the Invention

This invention relates to an apparatus and a method for extracting from a patient's body selected small tissue samples via a laparoscopic cannula; and more particularly to an apparatus and a method which enables a surgeon to reach a selected tissue sample via a conventional laparoscopic cannula and, thereafter, to positively engage the tissue, retract it via the cannula, and without touching the tissue to sealingly hold and contain it within a sample bottle for further investigation.

Background of the Related Art

Laparoscopic surgery is now commonplace, and enables surgeons to obtain relatively free access to assorted organs and tissues within the patient's body without the need to make large incisions from the outside of the body. Typically, a pointed conventional trocar is placed inside a cannula having a substantially cylindrical, smooth-walled elongate body, and the cannula and trocar are used together to penetrate through the abdominal wall of the patient via a relatively small local puncture. The trocar is then removed and the cannula is left in place during the surgical operation to receive any of a number of surgical tools or instruments . More than one cannula may be utilized during a surgical operation, with one typically being employed to dispose within the abdominal cavity fiberoptic means to provide light and to enable viewing of the organs and tissues lighted thereby. Another cannula may be utilized to insufflate the abdominal cavity with, for example, carbon dioxide gas under pressure.

Conventional cannulae, are usually made of a clear transparent smoothly formed plastics material such as ABS or Lexan™. Such cannulae, e.g., 100 as best seen in Fig. 1, are stored in sterile packages until needed and are then deployed with their distal ends within the abdominal cavity. The cannula 100 typically has a smooth-walled elongate cylindrical body portion 102 and a relatively enlarged proximal end portion 104 which remains outside the patient's body and enables sealing-in of the insufflation gas yet allows ready inserted reception of and immediate sealing to a variety of elongate surgical tools and instruments. These typically includes devices for grasping, incising either mechanically or by laser or electrical power, cauterization tools, and the like.

When tissues are excised, body fluids such as blood often leak out of severed circulatory vessels, i.e., arteries or veins. By the local application of heat, such leaking fluids may be coagulated, and by the combined application of heat and pressure the surgeon can cauterize the severed vessels. Nevertheless, within a short time into the surgical operation, there will soon be surgical debris comprising small bits of excised tissue, coagulated body fluids, charred material incidental to cauterization, and the like. Such surgical debris is most conveniently removed by lavage obtained by flowing a saline solution to entrain and remove unwanted bits of the patient's tissues and/or coagulated body fluids from the abdominal cavity. Eventually, the surgeon will excise tissue of particular interest, e.g., a suspect malign growth, tissue weakened by organic disease, or tissue contaminated by a toxin. The surgeon will typically want to extract a small amount of this questionable tissue to have it analyzed while the operation is under way. It is necessary, therefore, to extract the desired tissue without mingling it with incidental surgical debris and without dropping it within the insufflated abdominal cavity where it may become contaminated by other tissue and/or fluids. It is also important to seal the extracted questionable tissue promptly within a sealed sample container for transfer to the laboratory where it is to be analyzed.

Conventional tissue extraction tools such as forceps and the like, especially designed to be introduced via the cannula, are known but their use requires the surgeon to employ both hands and work in a manner which is stressful, distracting, and time-consuming. There is, therefore, a clearly-felt and long-existing need for a very simple apparatus and method to easily and positively grasp a small amount of excised tissue, to withdraw it cleanly via a conventional cannula without significant loss of insufflation gas from the patient's abdominal cavity, and to do so in such a manner that the extracted tissue can be promptly sealed into a sample container for rapid conveyance thereof to a facility for analyzing the same.

The present invention is intended to meet this need, and does so by providing a very easy-to-use and inexpensive solution by which a succession of tissue samples may be readily extracted via a conventional cannula and each of the extracted samples promptly sealed into a respective sample container for subsequent analysis . Persons or ordinary skill in the art are expected to consider obvious variations and modifications of the apparatus and method disclosed more fully hereinbelow, and such variations are intended to be comprehended within the invention as disclosed below with particular reference to the preferred embodiments thereof.

Summary of the Invention

It is a principal object of this invention to provide an inexpensive and easy-to-use apparatus which may be conveniently introduced into a patient's insufflated abdominal cavity via a cannula to positively engage to and extract a selected tissue sample in such a manner that the extracted tissue sample can be promptly sealed into a sample container for transfer to a facility for subsequent analysis.

It is another object of this invention to provide a system by which a surgeon, in the course of conducting a surgical operation via a cannula, can selectively extract tissue samples of small size with only a single hand, and in cooperation with an assistant have the extracted samples promptly sealed into respective sample containers for analysis.

In another aspect of this invention, it is a principal object to provide a method by which a surgeon, using only one hand, may in the course of a complex surgical operation extract through a conventional cannula selected small samples of excised tissue and thereafter have the extracted tissue samples sealed into respective containers for subsequent analysis.

These and other related benefits of this invention are realized in a first aspect thereof, by providing an apparatus for extracting a tissue sample from a patient via a cannula, which includes an elongate element sealingly passable into the cannula. A set of transverse bristles is mounted to a distal end of the elongate element for engaging to the tissue which is to be extracted. A means is provided for sealing the cannula when the elongate element is deployed within the cannula to engage the selected tissue with the bristles.

In another aspect of this invention there is provided an apparatus which includes a conventional cannula having an elongate cylindrical body with an open distal end deployable within the abdominal cavity of a patient, and a proximal enlarged head portion which contains a sealing element and a sealing flap biased thereto so as to contain a pressurized insufflation gas within the patient's abdominal cavity. The apparatus also includes an elongate tubular element having a smooth cylindrical outer surface, with a distal end provided with an internally threaded portion and a proximal end provided with a user-graspable head. The elongate tubular element is sealingly fitted into a cylindrical intermediate body which has an outer cylindrical surface sized to sealingly fit into a circular seal provided at the head end of the cannula. A tissue-engaging element, comprising a cylindrical top element having a through aperture and a helically-twisted length of wire passed therethrough is formed to hold a plurality of transverse bristles at a distal end. The top element is adhered to the helically-twisted portion of the bristles-holding wire and may be used to thread the same into or out of the internally threaded distal end portion of the elongate tubular element. The top element has an outer diameter smaller than an internal diameter of the cylindrical body so that, by relative motion between the tubular element and the cylindrical body, the tissue- engaging element attached to the distal end of the tubular f ^' ^ment can be received entirely into the cylindricε body.

In ye^*c another aspect of this invention, there is provided a method of selectively extracting a small tissue sample from a patient's body via a cannula and for thereafter promptly sealing the extracted sample into a container for safe containment and transfer of the tissue for analysis. The method is for extracting tissue samples during laparoscopic surgery on a patient through a conventional cannula which has an elongate cylindrical body portion ending in an open distal end deployable within the body of the patient and a proximal enlarged head portion having a closeable end provided with an aperture fitted with a resilient seal which includes an inner circular sealing portion for sealing to a cylindrical surface of corresponding size.^' The method includes the steps of inserting sealingly into the resilient seal of the cannula a cylindrical body having an outer cylindrical surface sized to sealingly fit to the resilient seal of the cannula in such a manner that the cylindrical body extends into the elongate cylindrical body portion of the cannula, a proximal end of the cylindrical body having an aperture and a sealing element mounted thereat; inserting an elongate tubular element having a smooth cylindrical outer surface sized to be sealingly received within the sealing element of the cylindrical body and having a distal end provided with an internally threaded portion; attaching to the threaded distal end of the tubular element a tissue- engaging element comprising a set of transverse bristles having distal ends pressable to selected tissue to become engaged therewith; pressing the bristles to engage the same with selected tissue; moving the bristles and the engaged tissue into the cylindrical body; and removing the cylindrical body and tissue from the cannula.

Brief Description of Drawings

Fig. 1 is a longitudinal, partially cross-sectional view of a preferred embodiment of the apparatus of this invention deployed within a conventional cannula inserted into the abdomen of a patient. Fig. 2 is a side elevation view of a distal end portion of the apparatus according to the preferred embodiment, to explain certain dimensional aspects thereof. Fig. 3 is a partial longitudinal cross-sectional view of the same elements of the apparatus as illustrated in Fig. 2.

Fig. 4 is an enlarged longitudinal cross-sectional view of a portion of the preferred embodiment shown in Figs. 1-3.

Fig. 5 is a partial longitudinal cross-sectional view to explain the manner in which a user may detach one portion of the apparatus according to the preferred embodiment to proceed toward sealingly containing an extracted tissue sample in a tissue container.

Fig. 6 is a partial cross-sectional view to illustrate a stage in the introduction or retraction of sample tissue into or from a tissue container.

Fig. 7 is a partial cross-sectional view of a sample container into which is sealingly contained a sample of tissue extracted by the apparatus according to the preferred embodiment.

Fig. 8 is a distal end view of the elements of the preferred embodiment which access and attach to excised tissue which is to be extracted from a patient's body.

Detailed Description of the Preferred Embodiments

As best seen in the longitudinal partially cross- sectioned view of cannula 100 per Fig. 1, a puncture (not numbered) is made into the abdominal wall 106, from external surface 108 through internal surface 110 of the abdominal wall (shown in c. ain lines) . Through this puncture, a length of the smooth-walled, cylindrical body portion 102 extends and opens into the abdominal cavity of the patient. The cylindrical body portion 102 of the cannula may be formed to any suitable length, and is preferably in the range 4 in. - 10 in. , with a diameter preferably in the range 1/4 in. - 1/2 in., and its distal opening is defined by a non-sharp edge. Cannula 100 is preferably made of a strong transparent plastics material such as ABS or Lexan™ by any conventional manufacturing technique.

The outer or proximal end of cannula 100 typically has a somewhat enlarged diameter head portion 104 with a flat, circular, end wall 112 provided with a circular aperture (not numbered) . Fitted to the rim of the circular aperture is an annular flexible sealing element 114 which has a smooth planar sealing surface 116 and an annular smooth circular inside sealing surface 118.

The enlarged portion 104 of cannula 100 typically is also provided with a planar, smooth-surfaced, pivotally supported sealing flap 120 (shown in a non-sealing position in Fig. 1) , which pivots about an internal pivot 122. Sealing flap 120 can thus pivot about pivot 122 so that its smooth planar sealing surface 122 presses evenly across the smooth planar sealing surface 116 of sealing element 114. This, in effect, entirely closes off the aperture at sealing element 114 to seal the inside of cannula body 100 to the abdominal cavity. A small biasing spring (not shown) may be provided at pivot 120 to apply a gentle biasing force to bias pivot sealing flap 120 toward its sealing position in contact with sealing surface 116 as just described.

Typically, more than one cannula is employed during a surgical procedure. One of these cannulae is fitted to a supply of pressurized gas, e.g., carbon dioxide, to insufflate the abdominal cavity in a safe and controllable manner. This permits the surgeon to view various organs inside the abdominal cavity of the patient by light-conveying and/or image-retrieval optic fibers introduced through yet another neighboring cannula. Once the surgeon has insufflated the abdominal cavity, and has the capability to view and/or to project onto an external screen a selected view of the abdominal cavity and its contents, yet a third cannula is typically introduced so that its internal/distal end is located near the site where surgery is to be performed. Cannula 100, as described herein, would be such a cannula through which one or more surgical tools or instruments may be introduced individually and in succession by a surgeon to perform surgical procedures such as incisions, cauterization of vessels such as arteries, and coagulation of body fluids which would otherwise tend to interfere with the surgical procedure. However, when such surgical tools are employed, the incised/excised body tissues, coagulated fluids, leaked blood, and other surgical debris will tend to collect in the vicinity of the surgical site.

Quite often, e.g., to ensure that tissue at a particular site is not malign, damaged by toxins or disease, or the like, the surgeon will want to extract a small piece of excised tissue to have it examined more thoroughly under laboratory conditions. The viewing arrangement described above should facilitate precise location of the site at which the sample tissue is to be excised from the patient's body. Once this is done, the excised tissue sample must be handled carefully, i.e., it must not be allowed to become mixed in with other surgical debris, and must be promptly extracted and sealed away, preferably with some identifier provided to go with the tissue sample, , to facilitate the intended testing.

Traditionally, relatively simple tools having elongate bodies and pincer-like elements at a distal end have been deployed through the cannula to reach in and grasp the tissue. Manipulation of the tissue-grasping elements of such a tool is difficult, and may require the surgeon to switch all of his or her attention to the task of properly grasping the tissue with relatively small and clumsily-handled elements. Furthermore, when the tissue is thus removed from the patient, the surgeon or one of his or her assistants must carefully detach the tissue from the retraction tool or instrument and transfer it into a container, seal it, and then take the tissue to the analysis laboratory facilities.

According to the present invention, as best seen with particular reference to Fig. 1, there is provided a relatively simple structure which quickly facilitates the necessary activities as just identified. Thus, into the annular sealing element 114 is pressed a smooth-surfaced cylindrical body 150 which has an open distal end 152 at the end of a cylindrical wall of outer diameter "d^' , a wall thickness "t", and an internal diameter "d₂". See Fig. 5. The length of the inside space within the cylindrical body 150 is " 1^' as indicated in Fig. 1. The open cylindrical body 150 ends in a head portion 154 which has a diameter somewhat larger than "d^' and has a central small aperture (not numbered) around which is provided an annular groove 156 shaped and sized to closely retain therein a small circular sealing element 158 formed of a resilient material, e.g., in the form of a small O-ring of conventional type. Through this sealing element 158 is passed and partially supported by it a smooth-walled straight elongate cylindrical tubular element 160 having an outer diameter "d₃" and a distal end portion 162 which is internally threaded by a particular type of thread described more fully hereinbelow. This is best understood with reference to the enlarged view per Fig. 4. At the proximal end of tubular element 160 is provided a head 164 which includes a somewhat enlarged and rough-textured portion 166 having a non-smooth and easily-graspable surface, as best seen in Fig. 1. As the distal end of tubular element 160, there is provided a tissue-engaging element 200 which comprises a length of wire folded about its midpoint 202 so as to form a looped portion within which are held a plurality of bristles 204. The bent portions of the wire are twisted together to form a straight helically-twisted elongate portion 206, the outside surface of which, in effect, defines a spiral thread.

Surrounding the distal end of the spirally-twisted portion 206 is a top element 208 which is preferably formed of a somewhat resilient material, e.g., rubber, silicon, or the like. This top element 208 has a central cylindrical outer surface portion 210 of a diameter "d₄" somewhat smaller than the internal diameter "d₂" of cylindrical body 150 and, therefore, smaller than the inside diameter "D" of the cylindrical body portion 102 of cannula 100. See Figs. 1 and 8. On a distal side of cylindrical surface 210, top element 108 is formed to have a conically tapered surface portion 212 which smoothly rounds into an end surface 214. On a proximal side of cylindrical surface 210, top element 208 is formed to have an oppositely tapering conical surface portion 214 on which may be provided letters, numerals, or alphameric combinations of letters, numerals and other selected symbols uniquely identifying the particular tissue-engaging element 200 of which that particular top element 208 is a part. Thus, in Fig. 1 there is shown the indicator symbol "C7", in Fig. 2 there is shown a comparable indicator symbol "A3", and in Figs. 5, 6 and 7, there is shown another exemplary indicator symbol "Al". Persons of ordinary skill in the art can be expected to apply/employ whatever symbols are considered most suitable for a particular application.

As best seen in the enlarged view per Fig. 4, top element 208 is provided with an axial through aperture which, in the illustrated preferred embodiment, has two communicating portions 220, 224 of slightly different diameters although this is not essential. Thus, at the distal end of top element 208 there is provided a smaller diameter portion 220 into which is received a helically- twisted portion 206 of the wire holding bristles 204 and is adhered thereto by any suitable adhesive 222. In other words, top element 208 surrounds and is attached by adhesive 222 only to the helically-twisted essentially threaded outer surface of the portion 206. In the preferred embodiment as illustrated in Fig. 4, the through aperture provided centrally of top element of 208 also has a proximal portion 224 of a slightly larger diameter than the distal portion 220. None of the adhesive 222 is located within this larger diameter portion 224 which is formed to be slightly larger than the outside diameter "d₃" (see Fig. 1) of the tubular element 160.

As will now be appreciated by reference to Fig. 5, a user can grasp the central cylindrical surface 210 of top element 208 and, by turning it relative to the tubular elongate element 160 to threadedly engage the distal end of helically-twisted portion 206 of the tissue-engaging element 200 into the internally threaded distal end portion 162. As mentioned earlier, the internal threads provided in distal internally threaded portion 162 of elongate element 160 are not conventional threads but, instead, are threads shaped and sized to firmly engage with the essentially threaded external surface of helically-twisted wire portion 206. As a practical matter, a thin-walled stainless steel tube, which is essentially what elongate element 160 is, may be grasped in a collett and a thread-forming helically- twisted portion 206 may be forcibly rotated, forced, and threadedly engaged therewith. If the wire forming the helically-twisted portion is harder than the stainless steel material of tubular element 160, the desired ir.vernal threading can thus be readily formed and thereafter utilized to engage/disengage other such helically threaded portions 206 as desired. These practical aspects should be well understood by persons skilled in the mechanical arts, and exactly how the internal threads are formed in elongate element 160 is considered a matter of design choice.

Referring again to Fig. 1, it will be understood how, by suitable selection of dimensions, it should be possible for a user to grasp head 166 and to thereby either rotate tubular element 160 and the threadedly attached tissue-engaging element 200 and/or to move the same translationally along the axis of cannula 100. Furthermore, because cannula 100 can be moved with considerable freedom relative to the abdominal wall 106 of the patient, the bristles 204 can be located precisely to contact a selected piece of tissue 400 (see the bottom right corner of Fig. 1) . The bristles 204 can thereafter be forced against this element of tissue so that their ends penetrate into the tissue and become positively engaged therewith. If the tissue is soft, adherent, or elongate, e.g., a piece of an organ cut by a surgical tool previously applied through cannula 100, rotation of the contacting bristles 204 will effect adherence, wrapping around, and further positive engagement of the tissue 400 to the bristles 204.

The user may then pull on head 166 to translationally retract along the inside of cannula 100 the entire tissue-engaging element 200 with tissue 400 positively engaged thereby. Eventually, the tapered proximal end surface 214 of top element 208 will enter the open end 152 of cylindrical body 150 and, upon further retraction, the entire length "1₂" of the tissue- engaging element 200 will be received within the length "li" of cylindrical body 150. See Figs. 1 and 2. Note that, as described earlier, the outer diameter "d₄" of the cylindrical surface portion 210 of top element 208 is sized to be smaller than and therefore slidingly receivable within the inside diameter "d₂" of cylindrical body 150. Unless the positively engaged piece of tissue 400 is large, it too should be readily retracted just within the open end 152 of cylindrical body 150.

The user may then pull on and retract via sealing element 114 of cannula 100 the entire length " 1^' of cylindrical body 150, with the tissue-engaging element 200 and the attached tissue 400 contained entirely within. This ensures that the ends of bristles 204 will not cut or scrape sealing element 114 at the outside end of cannula 100.

Reference should now be had to Fig. 5 in which it is seen how, by reversing the translational direction of relative motion between cylindrical body 150 and head 166, the tissue-engaging element 200 becomes accessible to the thumb and forefinger, 500, 502, respectively, of a user's hand. By grasping head 166 and the central cylindrical surface 210, and twisting them in an unthreading relationship, the user can easily disengage the tissue-engaging element 200 from the elongate tubular element 160. The disengaged tissue-engaging element 200 may then be turned over and the bristles 204, with the tissue sample 400 attached thereto, can be passed into a tissue sample container 600 through an opening 602 provided in a throat 604 thereof. By suitable dimensioning of the various elements, it should then be possible to locate tissue sample 400 sealingly within the container 600 by a pressed fit between the central cylindrical portion 210 of resilient top element 208 within the throat 604. When this is done, the alphameric or other indicators by which that particular sample 400 is to be identified will be readily visible outside and above throat 604 of that container 600. Thus, even when a number of such containers each containing its respective sample of tissue are arranged adjacent to each other, e.g., on a sample-carrying cart or laboratory shelf, the surgeon's assistants should be able to readily pick out the particular sample which is of most immediate interest.

As will be readily appreciated, the user may then promptly thread on another tissue-engaging element 200 to elongate element 160 and pull on head 166 to draw elongate element 160 within and along the inside of cylindrical body 150, so that the bristles of the newly- attached tissue-engaging element 200 are contained within the inside of cylindrical body 150. The cylindrical body 150 may then be introduced sealingly into and past sealing element 114 in the end wall 112 of cannula 100. By holding on to head 154, the user can ensure that virtually the entire length " 1^' of the cylindrical body 150 is introduced into cannula 100. If length " 1^' is selected appropriately, the very distal end portion of cylindrical body 150 will be received just into the elongate cylindrical portion 102 of cannula 100. The user may then press on head 166 to further advance the new bristles 204 out of the distal end of cylindrical body 102 of cannula 100 and, as described above, use them to engage positively with another tissue sample. The process should thus be clear, and should be seen as requiring the surgeon to devote very little time or attention yet ensuring that selected tissue samples are promptly and safely retracted without harming sealing element 114 of cannula 100. This ensures that a surgeon can remove a plurality of tissue samples, promptly seal each of them into a respective container, and be able to do so without damaging the seal of that particular cannula 100.

Once the tissue sample sealed into a particular container 500 has been extracted therefrom, by pulling on the corresponding top element 208 to disengage it from the throat 604 of that container 600, the tissue analyst may use forceps to remove the tissue sample and may then discard that particular-engaging element 200 which has now served its intended purpose. Such a tissue-engaging element 200, because it does not contain expensive materials and does not have to be built to very exacting standards, thus becomes a very useful but otherwise affordably disposable element for the surgeon's use.

The bristles 204 may be made of a stiff flexible plastics material or even a chemically-inert metal, e.g., the so-called "bristles" may be made of stainless steel wire. Their transverse span "S", as best seen in Figs. 2 and 8, should be smaller than diameter "d₄" of top element 208 to facilitate passage into and out of cylindrical body 150. Persons of ordinary skill in the art will no doubt consider providing small end portions at the ends of bristles 204 to create a hooking action more positively engaging the tissue sample. Such minor and obvious variations of the basic concept are considered to be comprehended within the present disclosure and users are expected to consider modifying the disclosed invention to suit their particular needs in such manner.

Although the present invention has been described and illustrated in detail, it should be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A system for extracting tissue samples during laparoscopic surgery on a patient, comprising: a cannula having an elongate cylindrical body portion ending in an open distal end and a proximal enlarged head portion communicating with the cylindrical body portion and having a closeable end, wherein the closeable end has a pivotally mounted sealing flap and an aperture provided with a resilient annular peripheral seal having a first sealing portion sealable by the sealing flap and an inner circular second sealing portion for sealing to a cylindrical surface of corresponding size; an elongate tubular element having a smooth cylindrical outer surface, a distal end provided with an internally threaded portion, and a user-graspable head at a proximal end; a cylindrical intermediate body having an outer cylindrical surface sized to sealingly fit into the second circular portion of the peripheral seal, a distal end closely receivable into the elongate cylindrical body portion of the cannula, and a proximal end provided with an aperture and a sealing element mounted at said aperture for resiliently sealing around the outer surface of the tubular element inserted therethrough; and a tissue-engaging element, comprising a generally cylindrical top element having a through aperture, a length of wire bent double to define a looped portion holding a set of transverse bristles and having two end portions helically twisted to form a handle portion extending through the aperture of the top element to be threaded into the internally threaded portion of the elongate tubular element, the top element being attached to the helically twisted handle portion in such a manner as to facilitate threading thereof into the internally threaded portion of the tubular element, wherein the top element has an outer diameter smaller than an internal diameter of the cylindrical body so that, by relative motion between the tubular element and the cylindrical body, the tissue-engaging element can be received entirely into the cylindrical body.

2. The system according to claim 1, wherein: the transverse bristles are made of a stiff elastic material and have distal ends disposed so as to engage with selected tissue, the bristles being sized so as to be received within the cylindrical body while maintaining engagement with the selected tissue.

3. The system according to claim 1, further comprising: a tissue container means having an opening which is sized to receive the bristles and tissue engaged i therewith and which can be sealingly closed by the top element of the tissue-engaging element.

4. The system according to claim 2, further comprising: a tissue sample container means having an opening which is sized to receive the bristles and tissue engaged therewith and which can be sealingly closed by the top element of the tissue-engaging element.

5. The system according to claim 2, further comprising: indicator means provided to the top element for specifically identifying tissue engaged to the bristles.

6. The system according to claim 4, further comprising: indicator means provided to the top element for specifically identifying tissue engaged to the bristles.

7. The system according to claim 1, wherein: the elongate tubular element is formed of stainless steel, and a plurality of additional tissue-engaging elements are provided, the respective top elements of which are provided with respective indicator means for enabling identification of tissues engaged by the corresponding bristles.

8. The system according to ^'claim 7, further comprising: a plurality of tissue container means each having an opening which is sized to receive therein a respective one of the tissue-engaging elements and tissue engaged thereby, each opening being sized and shaped to be sealingly closed by the corresponding top element in such a manner that the indicator means is located outside the container means and is readily visible.

9. The system according to claim 2, wherein: the through aperture of the top element is formed and sized so as to receive the distal end of the tubular element when the handle portion of the tissue-engaging element is threaded therein.

10. A device for obtaining selected tissue samples incised within a patient's body during laparoscopic surgery, through a conventional cannula which has an elongate body portion and a head portion provided with a circular seal and a pivotable flap sealable against a surface of the circular seal, comprising: an elongate tubular element having a smooth cylindrical outer surface, a distal end and a user graspable head at a proximal end; a cylindrical body, having an outer cylindrical surface sized to sealingly fit into the circular seal of the cannula, a distal end closely and sealingly receivable into the body portion of the cannula, and a proximal end provided with an aperture and a sealing element mounted at said aperture for resiliently sealing around the outer surface of the tubular element inserted therethrough; and a tissue-engaging element, comprising a set of transverse bristles and having two end portions twisted helically to form a handle portion extending through the aperture of the top element to be threaded into the internally threaded portion of the tubular element, the top element being attached to the helically twisted handle portion in such a manner as to facilitate threading thereof into the internally threaded portion of the tubular element, wherein the top element has an outer diameter smaller than an internal diameter of the cylindrical body so that the tissue-engaging element can be received entirely into the cylindrical body.

11. The device according to claim 10, wherein: the through aperture of the top element is formed and sized so as to receive therein the distal end of the tubular element when the handle portion of the tissue- engaging element is threaded therein.

12. The device according to claim 10, wherein: the transverse bristles are made of a stiff elastic material and have distal ends disposed so as to engage with selected tissue, the bristles being sized so as to I be received within the cylindrical body while maintaining engagement with the selected tissue.

13. The device according to claim 10, wherein: a tissue container means having an opening which is sized to receive the bristles and tissue engaged therewith and which can be sealingly closed by the top i element of the tissue-engaging element.

14. The device according to claim 12, wherein: a tissue sample container means having an opening which is sized to receive the bristles and tissue engaged therewith and which can be sealingly closed by the top ■ element of the tissue-engaging element.

15. The device according to claim 12, wherein: indicator means provided to the top element for specifically identifying tissue engaged to the bristles.

16. The device according to claim 14, wherein: a tissue sample container means having an opening which is sized to receive the bristles and tissue engaged therewith and which can be sealingly closed by the top element of the tissue-engaging element.

17. The device according to claim 10, wherein: the elongate tubular element is formed of stainless steel, and a plurality of additional tissue-engaging elements are provided, the respective top elements of which are provided with respective indicator means for enabling identification of tissues engaged by the corresponding bristles.

18. The device according to claim 17, wherein: a plurality of tissue container means each having an opening which is sized to receive therein a respective one of the tissue-engaging elements and tissue engaged thereby, each opening being sized and shaped to be sealingly closed by the corresponding top element in such a manner that the indicator means is located outside the container means and is readily visible.

19. A method of extracting tissue samples during laparoscopic surgery on a patient through a cannula which has an elongate cylindrical body portion ending in an open distal end and a proximal enlarged head portion communicating with the cylindrical body portion and having a closeable end provided with a pivotally mounted sealing flap and an aperture fitted with a resilient seal having a first sealing portion sealable by the sealing flap and an inner circular second sealing portion for sealing to a cylindrical surface of corresponding size, comprising the steps of: inserting sealingly into the resilient seal of the cannula a cylindrical body having an outer cylindrical surface sized to sealingly fit into the inner circular portion so that a distal end of the cylindrical body extends into the elongate cylindrical body portion of the cannula, wherein a proximal end of the cylindrical body has an aperture and a sealing element mounted at said aperture for resiliently sealing around the outer surface of a correspondingly sized tubular element inserted therethroug ; inserting an elongate tubular element having a smooth cylindrical outer surface sized to be sealingly received within the sealing element of the cylindrical body and having a distal end provided with an internally threaded portion and also having a user-graspable head at a proximal end located outside the cannula; and attaching to the distal end of the tubular element a tissue-engaging element comprising a set of transverse bristles sized to be receivable within the cylindrical body by relative movement between the elongate tubular element and the cylindrical body, the bristles having distal ends pressable to tissue to become engaged therewith; pressing the bristles to selected tissue to engage with the same; moving the tissue-engaging element including the bristles thereof and the engaged tissue into the cylindrical body; and removing the cylindrical body, the tissue-engaging element, and the engaged tissue from the cannula, whereupon the sealing flap of the cannula seals the contents of the patient's abdominal cavity.

20. The method according to claim 19, comprising the further step of : detaching the tissue-engaging element from the elongate tubular element and placing the bristles and the engaged tissue inside a container means in such a manner that a portion of the tissue-engaging element sealingly closes the container means to thereby seal in and retain the engaged tissue within the container means.

21. An apparatus for extracting a tissue sample from a patient via a cannula, comprising: an elongate element sealingly passable into and movable while in the cannula; a set of transverse bristles mounted to a distal end of the elongate element for engaging to the tissue sample which is to be extracted; and means for sealing the cannula when the elongate element is deployed and moved within the cannula during use to engage the tissue with the bristles.