referring to the drawings , and more particularly to fig1 there is shown the needle core biopsy instrument or tissue sample extractor 10 embodying the principles of the present invention . the instrument / extractor 10 comprises a first biopsy cannula 12 that is shaped and configured to be coaxially mounted within second cutting cannula 14 . both first biopsy cannula 12 and second cutting cannula 14 have proximal and distal ends , wherein the proximal end of the first biopsy cannula 12 and second cutting cannula 14 have proximal and distal ends , wherein the proximal end of the first biopsy cannula 12 is attached to the first shoulder 16 and the proximal end of the second cutting cannula 14 is attached to second shoulder 18 . the distal ends of first cannula 12 and second cannula 14 are more clearly depicted in fig3 and 6 , respectively . the distal end of first cannula 12 includes a sharpened , beveled cutting tip 44 preferably having a gradual , upwardly extending slope that forms a shovel - type scooped shape . such scoop - like shape advantageously allows for more efficient and less traumatic tissue penetration than other cannula cutting tips currently in use . additionally , first cannula 12 has a hollowed - out biopsy reservoir 46 , also shown in fig5 formed proximal the beveled cutting tip 44 . the biopsy reservoir 46 preferably is formed having a semi - circular shape that advantageously allows for relatively large , generally cylindrically - shaped tissue samples to be extracted from the tissue mass . as will be discussed in more detail infra , the distal ends of the first and second cannulas 12 , 14 cooperate via relative axial movement to cut and contain a tissue sample within the biopsy reservoir 46 . at the rear portion of biopsy reservoir 46 is a lumen or channel 13 which runs the length of first cannula 12 and allows the biopsy reservoir 46 to establish fluid communication with a conventional syringe 22 via connector 76 , as shown in fig1 . such fluid communication between biopsy reservoir 46 and syringe 22 enhances the ability of the extractor 10 to draw in and isolate a tissue sample due to the generation of a vacuum force by the syringe 22 , which shall be discussed below . the distal end of second cannula 14 is preferably formed having a hollow , frusto - conical shape that is designed and configured to allow first cannula 12 to axially pass therethrough . the distal rim 48a of the frusto - conical portion 48 is sharpened so that distal rim 48a may cut and contain a tissue sample disposed within biopsy reservoir 46 when the rim 48a is axially passed across the biopsy reservoir 46 of the first cannula 12 . as shown in fig7 the distal end of first cannula 12 freely passes , via axial movement , through the distal end 48 of second cannula 14 . second cannula 14 also preferably includes a barrel section 50 that serves as a sleeve to protect and contain a biopsy sample contained within a biopsy reservoir 46 when such sample is extracted from a tissue mass . the first and second cannulas may be formed in differing lengths and diameters to be utilized for a wide variety of tissue sampling applications such as beast , prostate , deep body , lung and other soft tissue biopsies . in addition to being coaxially positioned relative to one another , first cannula 12 and second cannula 14 are maintained in an arrangement whereby the second cannula is constantly urged forward by biasing member 20 , more clearly depicted in fig1 . preferably , biasing member 20 comprises a spring that is interposed between the first shoulder 16 formed on the first cannula 12 and second shoulder 18 formed on the second cannula 14 . the distally urging biasing force exerted by spring 20 forces the second shoulder 18 , and hence second cannula 14 , to axially advance upon the first cannula 12 . in order to selectively control the position of the second cannula 14 relative to first cannula 12 , the extractor 10 of the present invention advantageously incorporates the use of introducer 26 . in the preferred embodiment , the introducer 26 is fabricated from polymer and / or metal materials that may be sterilized or disposed of , such materials being well known to those skilled in the art . preferably , the introducer 26 is comprised of two parts , namely a handle and syringe retainer 28 and a plunger retractor member 30 , more clearly depicted in fig1 . the handle and syringe retainer 28 comprises a handle portion as well as structure sized and configured for detachably interconnecting with the conventional syringe 22 . more specifically , the syringe retainer 28 preferably includes first and second syringe support members 58 , 60 and syringe support collar 62 which engage the syringe 22 and firmly hold the syringe 22 in position . additionally , there is provided slot 56 that is designed and configured to detachably engage with rim 22a on syringe 22 so as to further provide secure attachment with syringe retainer 28 . the plunger retractor member 30 of introducer 26 comprises a generally c - shaped member having a trigger member 32 depending therefrom . the rear portion of the plunger retractor member 30 has a slot 52 to receive plunger 24 on syringe 22 . as will be discussed , slot 52 provides means for retracting the plunger 24 such that a vacuum is created in syringe 22 and ultimately in biopsy reservoir 46 via lumen 13 shown in fig3 . mounted adjacent the top portion of the retractor member 30 is a cam bar 34 , which is preferably pivotally mounted 36 thereon . as more clearly illustrated in fig1 , the cam bar 34 includes a first can slot 38 and a second cam abutment shoulder or surface 40 . additionally , cam bar 34 has a groove 42 which allows the coaxially positioned first cannula 12 and second cannula 14 to pass therethrough . as will be discussed , the first cam slot 38 and second cam abutment surface 40 provide means for adjusting the relative axial position of second cannula 14 with respect to first cannula 12 . the handle and syringe retainer 28 and plunger retractor member 30 are preferably connected to one another via a sliding - type engagement . more specifically , the plunger retractor member 30 is removably mounted onto the rear portion of syringe retainer 28 such that surface 30a is received upon upper guideway 64 and flanked by elongate guide members 66 and 68 . additionally , surface 30b is received within lower guideway slot 70 such that trigger member 32 protrudes from the handle and syringe retainer 28 to form a gun - type configuration . in addition , the handle and syringe retainer 28 further include a spring - activated detent or locking member 72 to engage apertures formed on surface 30c of the plunger retractor member 30 , said apertures being more clearly depicted as 74a , b in fig1 , 12 , 13 , and 14 . such spring - activated locking member 72 , when aligned with locking apertures 74a , b , provide means for positioning the handle and syringe retainer 28 with respect to the plunger retractor member 30 such that desired depths and axial positioning of the cannulas 12 , 14 may be more easily attained when using the extractor 10 . importantly , spring - activated locking member 72 , when aligned with locking aperture 74b , maintains the introducer 26 in an orientation that causes second cannula 14 to axially retract about biopsy reservoir 46 in a proximal axial position . having thus described the structure of the biopsy instrument / extractor 10 of the present invention , the operation of the same shall now be described with specific reference to fig1 through 14 . preparatory for use , the first and second cannulas 12 and 14 are coaxially positioned with biasing member 20 interposed between the shoulders 16 and 18 . the proximal end 76 of the first cannula 12 may then be attached to the distal end of the syringe 22 . as shown in fig1 , the syringe 22 is mounted within handle and syringe retainer 28 with plunger 24 being received in slot 52 of the plunger retractor member 30 . additionally , cam bar 34 is positioned such that second shoulder 18 is received within first cam slot 38 . additionally , the spring - activated locking member 72 is received within locking aperture 74a in such a manner that relative orientation or position of the handle 28 and plunger retractor member 30 is maintained unless otherwise manually adjusted . fig1 a depicts the corresponding axial position ( i . e ., the distal axial position ) between first cannula 12 and second cannula 14 while the introducer 26 is maintained in the initial orientation depicted in fig1 . as illustrated , the second cannula 14 is selectively covers biopsy reservoir 46 while beveled cutting tip 44 axially protrudes or extend therebeyond . while the introducer 26 and first and second cannulas 12 , 14 are maintained in the orientation and relative axial position depicted in fig1 and fig1 a , the introducer 26 is then gripped , as shown in fig2 and the first and second cannulas are manually pressed or inserted into a tissue mass from which a sample is to be extracted . as mentioned above , the introducer 26 , namely the combination of handle and syringe retainer 28 and plunger retractor member 30 , is formed to have a gun - like shape that allows the user to manually insert the coaxially positioned cannulas 12 , 14 while maintained in this distal axial position and ultimately extract a sample of tissue using only one hand . such design advantageously allows the physician user to utilize their other hand so as to manipulate the tissue or perform some other function as may be required . during insertion of the first and second cannulas 12 , 14 through the tissue , the user forces both interconnected portions 28 , 30 of the introducer 26 into the tissue in a direction indicated by the arrows &# 34 ; a &# 34 ; in fig1 . as should be noted , locking member 72 is engaged within aperture 74a during such insertion to prevent any relative axial movement between the handle 28 and plunger retractor member 30 . additionally , during such insertion the introducer 26 forces the cannulas 12 , 14 into the tissue whereby the sharpened beveled cutting tip 44 is forced directly into the tissue , and the cutting tip 44 of the first cannula simultaneously cuts the tissue and positions the cut tissue adjacent its periphery so as to overlie the second cannula 14 adjacent the biopsy reservoir 46 . once embedded within the tissue and having cut the tissue sample , the introducer 26 is manipulated such that the handle and syringe retainer 28 of the introducer 26 remains stationary while the plunger retractor member 30 is rearwardly retracted in the direction indicated by &# 34 ; b &# 34 ;. the plunger retractor member 30 is retracted , via manipulation of trigger member 32 , such that spring - activated locking member 72 is released ( i . e ., overcome ) from locking aperture 74a and subsequently engage with locking aperture 74b as shown in fig1 . due to the engagement of the second shoulder 18 with the cam slot 30 of the cam bar 34 , during such rearward movement , the second cannula 14 axially retracts relative the first cannula 12 and is disposed in its proximal axial position wherein the biopsy reservoir 46 is exposed to the tissue mass 82 , as depicted in fig1 a . accordingly , the axial retraction of the frusto - conical end portion 48 of second cannula 14 allows such cut tissue mass 82 to be received within the biopsy reservoir 46 . advantageously , during such retraction of the plunger retractor member 30 relative to handle and syringe retainer 23 , a vacuum is generated in syringe 22 such that the previously cut tissue mass 82 is drawn downwardly into the biopsy reservoir 46 as depicted in fig1 a . having effectively drawn the mass of tissue 82 to be extracted into the biopsy reservoir 46 , the cam bar 34 is manually raised in the direction indicated by the letter &# 34 ; d &# 34 ; in fig1 such that the second shoulder 18 is released from first cam slot 38 . spring member 20 preferably provides sufficient force such that upon release from first cam slot 38 the second cannula 14 rapidly axially advances with sufficient force to cause the sharpened distal end 48a of the second cannula 14 to sever and retain the tissue sample 82a to be extracted within biopsy reservoir 46 . such forward axial movement of the second cannula 12 continues until the second shoulder 18 abuts the second cam abutment surface 40 . the cross - sectional view depicting this distal axial position of the second cannula 14 depicted in fig1 a , which corresponds with the abutment between second shoulder 18 and second cam abutment surface 40 , as shown in fig1 . as shown , in this distal axial position , the second cannula 14 securely captures the cut tissue mass 82a within the biopsy reservoir . having thus isolated the tissue sample 82a from tissue mass 82 , the extractor 10 , and hence first and second cannulas 12 , 14 , may both be removed from the tissue mass by withdrawal of the extractor 10 where the tissue sample 82a may be recovered from the biopsy reservoir 46 and subsequently examined . alternatively , as illustrated in fig1 , the present invention provides that cam bar 34 may be raised even further about pivot 36 to allow second shoulder 18 , and thus second cannula 14 , to remain in place while introducer 26 , syringe 22 , and first cannula 12 may be manually withdrawn in the direction indicated by the arrow &# 34 ; e &# 34 ;. advantageously , by allowing the second cannula 14 to remain stationary within tissue mass 82 , the user , if desired , may make further tissue sample extractions through second cannula 14 in the manner described above . advantageously , by using the extractor 10 of the present invention , the user will not have to make repeated punctures into the tissue which will thus facilitate the extraction of multiple samples while subjecting the subject to a less traumatic experience as compared to other devices known in the art . referring now to fig1 - 17 , a disk guide assembly 98 comprises first 100 and second 102 disk guides having a circular channel 103 formed therein so as to slidably receive the second shoulder 18 . second shoulder 18 is thus prevented from moving side - to - side and upward by the disk guide assembly 98 , particularly during the insertion process . this disk guide assembly allows rotation of the cannula assembly through 360 degrees . as those skilled in the art will appreciate , it is common to exert pressure upon the tissue sample extractor of the present invention during the insertion process which tends to bend the first biopsy cannula 12 and the second cutting cannula 14 upward with respect to the device . such bending of the first biopsy cannula 12 and second cutting cannula 14 is undesirable because it interferes with proper operation of the device . thus , the optional disk guide assembly 98 assures reliable operation of the present invention . the disk guide assembly 98 may either be formed as an integral part of the device or , optionally , may comprise an add - on assembly . those skilled in the art will appreciate that various different configurations of the disk guide assembly 98 are likewise suitable for limiting movement of the second shoulder 18 in a longitudinal direction with respect to the first biopsy cannula 12 and second cutting cannula 14 . referring now to fig1 , an optional seal 110 is disposed about the first biopsy cannula 12 and urged into abutment with the second shoulder 18 such that it prevents vacuum leakage intermediate the first biopsy cannula 12 and the second cutting cannula 14 . the seal 110 preferably has shoulder 112 formed thereon so as to receive the distal end of the spring 120 . those skilled in the art will appreciate that various other configurations of the optional seal 110 are likewise suitable . referring now to fig1 and 20 , the second cutting cannula 14 is preferably formed to have a slanted or beveled cutting tip 135 formed thereon so as to facilitate reliable cutting of the biopsy tissue samples . the biopsy reservoir 46 is preferably formed to have an obstructor 128 disposed at the proximal end thereof so as to prevent vacuum from pulling the cut tissue sample into the lumen 13 of the first biopsy cannula 12 . the obstructor 128 is preferably formed by forming an undercut 126 at the proximal end of the biopsy reservoir 46 and then bending the proximal protruding portion or tab 128 formed thereby in the wall of the first biopsy cannula 12 inward so as to partially obscure the lumen 13 of the first biopsy cannula 12 . the tab 128 is bent sufficiently to assure that the biopsy tissue sample remains within the biopsy reservoir , yet still allows the vacuum to draw the tissue sample into the biopsy reservoir . optionally , similar but shallower undercut 122 may be formed at the distal end of the biopsy reservoir 46 to define distal tab 124 . the tip 120 of the first biopsy cannula 12 is preferably formed by machining a solid plug 132 , preferably via electron discharge machining , i . e ., either standard or wire electron discharge machining , so as to form a scooped out portion 134 which defines a sharp point 136 . the solid plug 132 may either first be attached to the first biopsy cannula 12 , so as to facilitate handling thereof during the machining process , or alternatively , may be formed at the end of an elongate bar and then cut therefrom prior to insertion into the first biopsy cannula 12 . the solid plug 132 is preferably attached to the first biopsy cannula 12 via forming at least one crimp 123 in the first biopsy cannula 12 , which is pressed into a corresponding cut - out or dimple formed in the solid plug 132 or by being press fit into the first biopsy cannula 12 . alternatively , those skilled in the art will appreciate that various other different means , as discussed above , may be utilized to attached the solid plug 132 to the first biopsy cannula 12 . further , various different combinations of such means may be utilized . the cross - sectional area or profile defined by the scooped out portion 134 of the solid plug 132 facilitates easy insertion into tissue , while maintaining sufficient strength to prevent premature dulling or deformation of the sharp point 136 . the diameter of the solid plug 132 may either be approximately equal to the outer diameter of the first biopsy cannula 12 , so as to provide a substantially flush fit therewith , or alternatively may similarly be approximately equal to the outer diameter of the second cutting cannula 14 . according to the preferred embodiment of the present invention , the cannula assembly , comprised of the first biopsy cannula 12 , the second cutting cannula 14 , and preferably the spring 20 , seal 110 , and second shoulder 18 as well , may be formed so as to be disposable . thus , these items are preferably formed of comparatively inexpensive materials , which is made possible due to their limited expected life . by making the cannula assembly disposable , a high degree of convenience is achieved . thus , the cannulas do not need to be sterilized between uses , rather a new cannula assembly is installed for each use . there has thus been disclosed a tissue sample extractor , with various preferred embodiments thereof , having been described in detail with the various advantages being set forth . it is understood , however , that equivalents are possible and that variations in structure may be made that fall within the underlying principles of the present invention .
a needle core biopsy instrument / extractor for extracting a tissue sample via needle aspiration is disclosed . the extractor comprises a first cannula having a sharpened , beveled cutting tip and biopsy reservoir formed on it distal end . the proximal end of the first cannula is in fluid communication with a conventional syringe such that when the plunger of the syringe is retracted via manipulation o the extractor , a vacuum is created within the biopsy reservoir of the first cannula axially mounted about the first cannula is a second cutting cannula which is designed and configured to selectively cover and uncover the distal end of the first cannula . a biasing member , preferably a spring , is provided to urge the second cannula forward about the distal end of the first cannula . the syringe , coaxially positioned first and second cannulas , and biasing member are contained within an introducer which is preferably designed and configured to be manipulated by one hand . the handle slide and lever of the device are oriented in such a way as to allow the retention of tissue via vacuum and the severing of the specimen by the second cannula to be exactly timed by cam operation .