Apparatus and method for performing tissue biopsy

Abstract

An apparatus comprising: a handle having cavity extending between a distal end and a proximal end; a stylet extending distally; an inner cannula being disposed coaxial to the stylet; an outer cannula being disposed coaxial to the inner cannula; an actuation mechanism being configured to (i) selectively move the inner cannula relative to the stylet, and (ii) selectively move the outer cannula relative to the inner cannula and the stylet; wherein the outer cannula comprises a sharpened distal surface, and further wherein the outer cannula comprises at least one leaflet disposed proximal to the sharpened distal surface; and further wherein the at least one leaflet is configured to move from a first position, in which the at least one leaflet does not encroach upon the lumen of the outer cannula to a second position in which the at least one leaflet encroaches upon the lumen of the outer cannula.

Description

[0001] APPARATUS AND METHOD FOR PERFORMING TISSUE BIOPSY

[0002] Mermaid Medical, Inc.

[0003] Inventors

[0004] Adrian C. Ravenscroft

[0005] Julizette C. Melgar

[0006] Reference To Pending Prior Patent Applications

[0007] This patent application claims benefit of:

[0008] (i) pending prior U.S. Provisional Patent Application Serial No.

[0009] 63 / 753,724, filed 02 / 04 / 2025 by Mermaid Medical, Inc. for BIOPSY DEVICE (Attorney’s Docket No. MERMAID-2 PROV); and

[0010] (ii) pending prior U.S. Provisional Patent Application Serial No.

[0011] 63 / 850,071, filed 07 / 24 / 2025 by Mermaid Medical, Inc. for BIOPSY DEVICE (M-BLOOM) (Attorney’s Docket No. MERMAID-6 PROV).

[0012] The two (2) above-identified patent applications are hereby incorporated herein by reference.

[0013] Field Of The Invention

[0014] This invention relates to medical devices in general, and more particularly to biopsy devices and novel methods for effecting biopsy of tissue.

[0015] Background Of The Invention

[0016] Tissue biopsy, in particular, soft tissue biopsy, is a commonly performed medical procedure used to make pathologic diagnoses of

[0017] MERMAID-0206certain medical conditions (e.g., cancer, etc.). Soft tissue biopsy is generally performed using a percutaneous, minimally-invasive approach in which a small sample of soft tissue is removed from a predetermined area (e.g., the lung, the kidney, a lesion on the anatomy, etc.). Pathological examination of the small tissue sample so obtained can subsequently be used to make (or confirm) a diagnosis of a medical condition.

[0018] In order to facilitate effective, accurate pathological examination of the small tissue sample obtained by biopsy, it is necessary for the sample to meet at least the following criteria: adequate sample size, tissue integrity, intended target tissue, and biopsy reliability / patient comfort.

[0019] More particularly, in order to obtain adequate sample size, the sample obtained by biopsy must be of an appropriate size for the desired pathological examination. By way of example but not limitation, in certain liver biopsies, it has been found that biopsy sample sizes of approximately 1.5 cm - 3.0 cm in length are required to facilitate accurate pathological examination.

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

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

[0022] Finally, although soft tissue biopsy is generally performed as a minimally-invasive procedure, it is important to minimize the number of

[0023] MERMAID-0206times that the biopsy needle must be advanced into the patient’s tissue. Attempted biopsies that do not obtain sufficient tissue, or which obtain damaged tissue samples, generally require repetition of the biopsy procedure. Since such repeated procedures tend to lead to patient discomfort and increased procedure time (and hence increased expense), it is desirable to obtain an adequate biopsy sample to facilitate pathologic examination without having to repeat the biopsy procedure.

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

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

[0026] MERMAID-0206More particularly, and looking now at Figs. 1 and 2, there is shown an exemplary prior art CNB “side cut” biopsy device 5 configured to perform a “side cut” biopsy. Biopsy device 5 generally comprises a handle (not shown) having an outer cannula 10 extending distally therefrom.

[0027] Outer cannula 10 generally comprises a proximal end (not shown), a distal end 15, and a lumen 20 extending therebetween. A stylet 25 comprising a proximal end (not shown), a distal end 30, and a body 35 extending therebetween is slidably, coaxially disposed within lumen 20 of outer cannula 10 so as to be selectively movable relative to outer cannula 10. Body 35 of stylet 25 comprises a cut-out defining a sample chamber 40 disposed just proximal to distal end 30, whereby to receive a cored-out soft tissue sample, as will hereinafter be discussed.

[0028] In use, side-cut biopsy device 5 is advanced so that the distal end of outer cannula 10 is disposed at the surface of the tissue to be sampled. Stylet 25 is then moved distally so as to enter into, and cut, the tissue that is to be sampled. Importantly, stylet 25 is advanced distally into the tissue to be sampled such that sample chamber 40 becomes filled with the tissue to be sampled. Specifically, stylet 25 comprises a sharp distal end configured to effect coring of the tissue to be sampled. As used herein, the term “coring” refers to the cutting action effected when a sharp-edged stylet (or tube) performs tissue separation along a tract by using a leading edge; the term “shearing” refers to the cutting action effected when the end of the tissue sample is cut at the end of the throw length of stylet 25 (i.e. , when stylet 25 is in its distal most position). Next, outer cannula 10 is advanced distally over stylet 25, with distal end 15 of outer cannula 10 shearing tissue as it moves distally so as to leave a sample of tissue in sample chamber 40. Outer cannula 10 and stylet 25 can thereafter be removed proximally from the tissue, with a core of tissue remaining in

[0029] MERMAID-0206sample chamber 40, whereby to retain the sample of tissue in sample chamber 40.

[0030] While the foregoing “side-cut” approach can work adequately for some applications, it suffers from some significant drawbacks. For example, and looking now at Fig. 2, it will be appreciated that the “core” of tissue sample so obtained comprises a generally D-shaped semi-circular cross-section rather than a circular cross section. This results in a smaller sample size than can be obtained with an “end cut” needle biopsy device (see below). By way of further example but not limitation, it has been found that while distal movement of the outer cannula 10 relative to stylet 25 can effect shearing of the tissue, it is common to get tissue fragmentation / incomplete shearing, resulting in a need to repeat the biopsy procedure, and / or resulting in a tissue samples that lacks tissue integrity and is not suitable for pathologic examination.

[0031] Another type of biopsy device commonly used to perform soft tissue biopsy is the “full core” (sometimes also referred to as an “end-cut”) biopsy device.

[0032] More particularly, and looking now at Figs. 3 and 4, there is shown an exemplary prior art CNB “full core” biopsy device 45 configured to perform a “end cut” biopsy. Biopsy device 45 generally comprises a handle (not shown) having an outer cannula 50 extending distally therefrom. Outer cannula 50 generally comprises a proximal end (not shown), a distal end 55 terminating in a sharpened distal end surface 53 (i.e. , a sharpened end surface extending about the circumference of distal end 55), a distal cutting feature (not shown) configured to selectively shear tissue when actuated, and a lumen 60 extending therebetween. A stylet 65 comprising a proximal end (not shown), and a sharpened distal end 70 is coaxially disposed within lumen 60 of outer cannula 50. In use, stylet

[0033] MERMAID-020665 is disposed within outer cannula 50 such that sharpened distal end 70 of stylet 65 is aligned with (or protrudes slightly distally from) distal end 55 of outer cannula 50 as full-core biopsy devices 45 is navigated through the tissue to the biopsy device. Full-core biopsy device 45 is advanced so that the distal end of outer cannula 50 is disposed at the surface of the tissue to be sampled. Outer cannula 50 is then moved distally such that sharpened, distal end surface 53 of outer cannula 50 cores out the tissue that is to be sampled as sharpened distal end surface 53 performs separation of the tissue along the tract that it advances along and the distal cutting feature (not shown) is actuated to shear the tissue that is to be sampled from the native tissue. Outer cannula 50 can then be moved distally so that distal end 55 of outer cannula 50 passes over the tissue sample if necessary, whereby to encase and retain a tissue sample S within lumen 60 of outer cannula 50.

[0034] It will be appreciated that both CNB “side cut” biopsy device 5 and CNB “full core” biopsy device 45 can be configured as either “semi automatic” or “fully automatic” devices. More particularly, and looking now at Figs. 4A, there is shown exemplary “side cut” biopsy device 5 configured as a “semi-automatic” device. With the “semi-automatic” configuration, the biopsy function of the device consists of only one action in which sample chamber 40 is positioned at the end of the sampling target before being moved distally into the tissue (i.e., before being “fired”). With such a “semi-automatic” configuration, sample chamber 40 is advanced manually into the target tissue and then outer cannula 10 is subsequently moved distally over stylet 25 / sample chamber 40 upon the triggering of the actuation mechanism of CNB “side cut” biopsy device 5.

[0035] By contrast, with a “fully automatic” configuration and looking now at Fig. 4B, the distal movement of stylet 25 and outer cannula 10 into the

[0036] MERMAID-0206tissue to be sampled comprises two actions. That is, with a “fully automatic” device stylet 25 and outer canula 10 are automatically moved distally in sequential actions triggering of the actuation mechanism of CNB “side cut” biopsy device 5.

[0037] While the foregoing “full-core” approach can work adequately for some applications, it suffers from some significant drawbacks. For example, and looking now at Fig. 4, it will be appreciated that the tissue sample “core” obtained comprises a generally circular cross-section (i.e. , such that the “core” of sample S comprises a cylinder), however, it has been found that while the distal cutting feature of prior art CNB “full-core” biopsy devices can effect some shearing of the tissue, it is common to get tissue fragmentation / incomplete shearing, resulting in a need to repeat the biopsy procedure, and / or resulting in a tissue sample that lacks tissue integrity and is not suitable for pathologic examination. In particular, it has been found that “full-cut” devices such as prior art biopsy device 45 frequently fail to adequately sever the tissue sample from the tissue that it is sampled from, resulting in failed biopsy procedures and / or inadequate tissue samples for pathologic examination.

[0038] The failure to adequately sever the tissue sample S from the native tissue being sampled arises from (i) the inadequate cutting effect of the distal cutting feature of outer cannula 50, which can fail (e.g., due to mechanical failure) to completely sever tissue sample S from the native tissue, (ii) movement of sample S within lumen 60 of outer cannula 50 relative to outer cannula 50 as the outer cannula is advanced distally or retracted proximally (thereby potentially reducing shearing of tissue as the outer cannula moves distally or causing the distal cutting feature to cut the tissue at an undesirable location), and / or (iii) a combination of both (i) and (ii). As a result of inadequate severing of the tissue sample S from the

[0039] MERMAID-0206native tissue, it is commonly found that with prior art biopsy devices, tissue sample S can “fall out” of lumen 60 of outer cannula 50 when the outer cannula is retracted proximally out of the anatomy because a portion of the tissue is inadequately severed from the native anatomy (and thereby tethered to the native anatomy).

[0040] And it should be appreciated that it is not possible to merely increase friction between the tissue sample S and the interior surface of the sidewall defining lumen 60 because increased friction with the interior surface of the sidewall of lumen 60 (e.g., such as may occur if the surface of the sidewall is intentionally roughened) can cause damage to the tissue sample S when the tissue sample S is ejected out of lumen 60 to be subjected to pathologic examination. To the extent prior art biopsy devices comprise any mechanism / geometricfeature / roughened surface configured to retain sample S within lumen 60, tissue sample S can “fall out” of lumen 60 because the retention mechanism fails, or because the roughened surface does not generate enough friction between the surface and sample S to retain sample S within lumen 60.

[0041] Additionally, it will be appreciated that obtaining tissue sample S using a full core CNB requires precise timing of (i) distal movement of outer cannula 50 to core the tissue sample, and (ii) use of a distal cutting feature feature / mechanism to shear the tissue sample from the target tissue and / or retain the tissue sample in lumen 60 as the full core CNB device is removed from the anatomy. Prior art full core CNB biopsy devices generally utilize a complex timing mechanism contained in the handle of the biopsy device to control timing of the movement of outer cannula 50 relative to stylet 65. Furthermore, prior art “full-core” CNB biopsy devices generally rely on springs for generating the force required to move outer cannula 50 distally, with the trigger mechanism for releasing

[0042] MERMAID-0206the spring comprising elastically deformable, resilient plastic elements. Such elastically deformable, resilient plastic elements tend to work adequately for a single deployment of CNB 45, however, deformable plastic elements tend to quickly lose resiliency after multiple deployments, leading to a biopsy device that cannot be reliably deployed multiple times during a single procedure, and / or a biopsy device that can accidentally deploy even without actuating the trigger element (e.g., due to the failure of the elastically deformable, resilient plastic elements that such prior art devices rely on to act as a trigger). Moreover, to the extent that prior art devices comprise any retention mechanism at all, such a retention mechanism generally comprises a single retention feature disposed at the distal end of outer cannula 50. Due to the very small diameter of outer cannula 50, such a feature can be challenging to machine / mount, can present a delicate feature prone to breakage, and generally comprises a single element that cuts only 70-80% of the cross-section of tissue sample S and leads to eccentric balancing of force loads on the retention feature.

[0043] Thus there exists a need in the art for a new and improved biopsy device which facilitates superior coring, shearing and retention of a tissue sample S from the native tissue during a biopsy procedure, and which permits the biopsy device to selectively retain (and selectively eject) the tissue sample S within (or from) the biopsy device without damaging the tissue sample. There also exists a need in the art for a new and improved deployment mechanism for facilitating precisely-timed, controlled distal movement of a first element relative to a second element, which avoids the problems inherent in prior art biopsy devices.

[0044] Of The Invention

[0045] MERMAID-0206The present invention comprises the provision and use of a new and improved biopsy device that facilitates clean severing of a tissue sample S from the native tissue during a biopsy procedure, and which permits the biopsy device to selectively retain (and selectively eject) the tissue sample S within (or from) the biopsy device without damaging the tissue sample. The present invention also comprises the provision and use of a new and improved deployment mechanism that permits a first element (e.g., an inner cannula) to be moved distally a predetermined distance relative to a second element (e.g., an outer cannula) also moved distally a predetermined distance relative to the first element with precise timing, and which avoids the issues present in prior art deployment mechanisms.

[0046] In a preferred form of the invention, there is provided apparatus for obtaining a tissue sample from tissue, said apparatus comprising:

[0047] a handle having a distal end, a proximal end, and a cavity extending therebetween;

[0048] a stylet comprising a distal end and a proximal end, said stylet extending distally from the distal end of said handle;

[0049] an inner cannula comprising a distal end, a proximal end, and a sidewall enclosing a lumen extending therebetween, said inner cannula being disposed coaxial to said stylet;

[0050] an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said inner cannula;

[0051] an actuation mechanism disposed in said cavity of said handle, said actuation mechanism being configured to (i) selectively move said inner cannula relative to said stylet, and (ii) selectively move said outer cannula relative to said inner cannula and said stylet;

[0052] MERMAID-0206wherein said distal end of said outer cannula comprises a sharpened distal surface, and further wherein said outer cannula comprises at least one leaflet disposed proximal to said sharpened distal surface;

[0053] and further wherein said at least one leaflet is configured to move from a first position, in which said at least one leaflet is coincident with said side wall of said outer cannula and does not encroach upon said lumen of said outer cannula to a second position in which said at least one leaflet is not coincident with said side wall of said outer cannula and encroaches upon said lumen of said outer cannula.

[0054] In another preferred form of the invention, there is provided a method for obtaining a tissue sample from tissue, said method comprising:

[0055] providing apparatus comprising:

[0056] a handle having a distal end, a proximal end, and a cavity extending therebetween;

[0057] a stylet comprising a distal end and a proximal end, said stylet extending distally from the distal end of said handle;

[0058] an inner cannula comprising a distal end, a proximal end, and a sidewall enclosing a lumen extending therebetween, said inner cannula being disposed coaxial to said stylet;

[0059] an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said inner cannula;

[0060] an actuation mechanism disposed in said cavity of said handle, said actuation mechanism being configured to (i) selectively move said inner cannula relative to said stylet, and (ii) selectively move said outer cannula relative to said inner cannula and said stylet;

[0061] MERMAID-0206wherein said distal end of said outer cannula comprises a sharpened distal surface, and further wherein said outer cannula comprises at least one leaflet disposed proximal to said sharpened distal surface;

[0062] and further wherein said at least one leaflet is configured to move from a first position, in which said at least one leaflet is coincident with said side wall of said outer cannula and does not encroach upon said lumen of said outer cannula to a second position in which said at least one leaflet is not coincident with said side wall of said outer cannula and encroaches upon said lumen of said outer cannula;

[0063] advancing said handle distally until said distal end of said inner cannula is disposed against the tissue that is to be sampled;

[0064] actuating said actuation mechanism so as to (i) move said inner cannula and said outer cannula distally such that said inner cannula moves distally over the tissue sample and the tissue sample is received in said lumen of said inner cannula, and (ii) move said outer cannula distally such that said at least one leaflet is in said second position.

[0065] In another preferred form of the invention, there is provided apparatus for selectively moving a first object relative to a second object, said apparatus comprising:

[0066] a handle;

[0067] a carriage limiter comprising:

[0068] a carriage cavity mounted to said handle, said carriage cavity comprising a proximal end and a distal end;

[0069] at least one groove extending between said proximal end and said distal end, said at least one groove comprising a laterally-extending pocket extending orthogonal to a longitudinal axis of said at least one groove; and

[0070] MERMAID-0206at least one proximal stop and at least one distal stop disposed distal to said at least one proximal stop;

[0071] a first carriage mounted to a first object, said first carriage being disposed in said carriage cavity;

[0072] a second carriage mounted to a second object, said second carriage being disposed in said carriage cavity distal to said first carriage, wherein said second carriage comprises a radially-reduced region;

[0073] a deployment spring having a first end mounted to said handle and a second end contacting said first carriage so as to bias said first carriage distally;

[0074] a second spring having a first end mounted to said first carriage and a second end contacting said second carriage;

[0075] at least one bearing having a first end slidably received in said groove of said carriage limiter and a second end received in said radially-reduced region of said second carriage;

[0076] a trigger for (i) selectively restraining said first carriage and said second carriage in a proximal position in said carriage cavity against the power of said deployment spring, and (ii) selectively releasing said first carriage such that said first carriage and said second carriage move distally within said carriage cavity under the power of said deployment spring until said first carriage contacts said at least one proximal stop; wherein said at least one bearing prevents said second carriage from moving distally within said carriage cavity under the power of said second spring until said first end of said at least one bearing is received within said laterally-extending pocket of said groove, and wherein said at least one bearing permits said second carriage to move distally within said carriage cavity under the power of said second spring when said first end of said at least one bearing is received within said laterally-extending

[0077] MERMAID-0206pocket of said groove and said second end of said bearing moves out of said radially-reduced region of said second carriage under the power of said second spring; and

[0078] wherein when said first carriage contacts said at least one proximal stop, said first carriage is halted while said second carriage continues to move distally until said second carriage contacts said at least one distal stop.

[0079] In another preferred form of the invention, there is provided apparatus for obtaining a tissue sample from tissue, said apparatus comprising:

[0080] a handle;

[0081] a stylet comprising a proximal end and a distal end, said proximal end of said stylet being mounted to said handle;

[0082] an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said stylet such that said stylet extends through said lumen of said outer cannula;

[0083] at least one microgrip formed in said sidewall of said outer cannula, said at least one microgrip being configured to (i) bow inwardly so as to encroach upon said lumen of said outer cannula when said at least one microgrip is not in contact with said stylet, and (ii) be coincident with a plane defined by said sidewall of said outer cannula when said at least one microgrip is in contact with said stylet.

[0084] Brief Description Of The Drawings

[0085] These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be

[0086] MERMAID-0206considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:

[0087] Figs. 1 and 2 are schematic views showing an exemplary prior art CNB “side cut” biopsy device configured to perform a “side cut” biopsy;

[0088] Figs. 3 and 4 are schematic views showing an exemplary prior art CNB “full core” biopsy device configured to perform a “end cut” biopsy;

[0089] Figs. 4A and 4B are schematic views illustrating the operation of an exemplary prior art CNB “side cut” biopsy device;

[0090] Figs. 5-13, 13A, 13B, and 14-18 are schematic views showing a novel biopsy device formed in accordance with the present invention;

[0091] Figs. 19-23, 23A, 23B, 23C, 23D, and 24-26 are schematic views showing another novel biopsy device formed in accordance with the present invention; and

[0092] Figs. 27-32 are schematic views showing a novel actuation device formed in accordance with the present invention; and

[0093] Figs. 33, 34A, 34B, 36, 37A, 37B, and 38-40 are schematic views showing another novel actuation device formed in accordance with the present invention.

[0094] Detailed Description Of The Preferred Embodiments

[0095] The present invention comprises the provision and use of a new and improved biopsy device that facilitates clean severing of a tissue sample S from the native tissue during a biopsy procedure, and which permits the biopsy device to selectively retain (and selectively eject) the tissue sample S within (or from) the biopsy device without damaging the tissue sample. The present invention also comprises the provision and use of a new and improved deployment mechanism that permits a first element (e.g., an inner cannula) to be moved distally a predetermined

[0096] MERMAID-0206distance relative to a second element (e.g., an outer cannula) also moved distally a predetermined distance relative to the first element with precise timing, and which avoids the issues present in prior art deployment mechanisms.

[0097] Novel Biopsy Device Comprising Micro Grip

[0098] For Gripping Tissue Sample

[0099] Looking now at Fig. 5, there is shown a novel biopsy device 105 formed in accordance with the present invention. Biopsy device 105 generally comprises a handle 110, an outer cannula 115, an inner stylet 120, and an actuation mechanism 125 configured to selectively move outer cannula 115, as will hereinafter be discussed in further detail.

[0100] More particularly, and looking now at Figs. 5-8, outer cannula 115 generally comprises a distal end 130, a proximal end 135, and a sidewall 140 defining a lumen 145 extending therebetween. Distal end 130 of outer cannula 115 preferably terminates in a sharpened, beveled cutting edge 150 for facilitating cutting of a cored-out tissue sample S, as will hereinafter be discussed in further detail. In one preferred embodiment of the present invention, outer cannula 115 comprises a generally cylindrical geometry such that lumen 145 comprises a circular cross-section, however, it should be appreciated that outer cannula 115 may be formed with other geometries without departing from the scope of the present invention. By way of example but not limitation, if desired, outer cannula 115 may comprise an elliptical cross-section (Fig. 8) or an oval crosssection (Fig. 9). Outer cannula 115 may be made out of substantially any material (e.g., stainless steel, Nitinol, MP35N, Inconel, molybdenum-and / or titanium-containing alloys, super alloys, etc.) capable of providing desired column strength and flexibility, as will be apparent to one of skill in

[0101] MERMAID-0206the art in view of the present disclosure. In one preferred embodiment of the invention, outer cannula 115 comprises Nitinol.

[0102] At least one micro grip 155 is formed in sidewall 140 of outer cannula 115 at a location just proximal to distal end 130 of outer cannula 115. Micro grip 155 is preferably formed by cutting away (e.g., via laser cutting) a portion of sidewall 140 so as to form micro grip 155 as a thin, flexible element capable of deflecting inwardly so as to encroach upon lumen 145 of outer cannula 115, as will hereinafter be discussed in further detail.

[0103] More particularly, micro grip 155 is formed (e.g., heat treated, etc.) so as to be resilient. By way of example but not limitation, micro grip 155 may be formed from two laser cuts passing entirely through sidewall 140 of outer cannula 115, and micro grip 155 may be treated (e.g., heat treated) so as to “bow” radially-inwardly into lumen 145 unless subjected to a force that forces micro grip 155 radially outboard (i.e., so as to align with sidewall 140). In one preferred embodiment of the invention, micro grip 155 is configured to “bow” radially inwardly into lumen 145 unless micro grip 155 contacts stylet 120 disposed within lumen 145 such that stylet 120 applies a radially-outward-directed force to micro grip 155. Stated another way, micro grip 155 is preferably constructed such that when stylet 120 is coincident with (and contacts) micro grip 155, micro grip 155 is forced radially outwardly by stylet 120 such that micro grip 155 is radially aligned with the outer surface of outer cannula 115 (Fig. 6); when stylet 120 is not coincident with (and hence, does not contact) micro grip 155, micro grip 155 “bows” inwardly under its own resiliency so as to encroach upon lumen 145 (Fig. 7).

[0104] Micro grip 155 may be formed in substantially any geometry desired for a particular biopsy application. By way of example but not

[0105] MERMAID-0206limitation, and looking now at Fig. 6, in one preferred embodiment of the present invention, micro grip 155 comprises a two resilient legs 160, 165 and a central tissue mount 170. It will be appreciated that resilient legs 160, 165 and tissue mount 170 are preferably formed by cutting away a portion of sidewall 140 of outer cannula 115. By way of example but not limitation, such cutting away of sidewall 140 may be effected by laser cutting, electrochemical machining, micromachining, electropolishing, etc., as will be apparent to one of skill in the art in view of the instant disclosure. It will be appreciated that formation of micro grip 155 can be tailored to fine tune the dimensions of resilient legs 160, 165 and / or tissue mount 170, and / or to fine tune the resiliency of resilient legs 160, 165. See, for example, Fig. 11 , which shows an alternative form of micro grip 155.

[0106] Other geometries will be apparent to one of skill in the art in view of the instant disclosure and fall within the scope of the present invention.

[0107] It will be appreciated that central tissue mount 170 is the primary point of contact between biopsy device 105 and the cored-out tissue sample that is to be biopsied. Thus, it will be appreciated that the size and / or geometry of tissue mount 170 may be varied to increase holding force applied to the tissue sample without departing from the scope of the present invention.

[0108] In one preferred embodiment of the present invention, outer cannula 115 comprises a pair of diametrically-opposed micro grips 155.

[0109] As a result of this construction, and looking now at Fig. 10, the pair of diametrically-opposed micro grips 155 “bow” radially inwardly when stylet 120 is disposed proximal to micro grips 155, whereby to grip a tissue sample S disposed between micro grips 155, as will hereinafter be discussed in further detail.

[0110] MERMAID-0206Looking now at Fig. 12, if desired, micro grips 155 may be formed in sidewall 140 of outer cannula 115 so as to be arranged serially, i.e., with two (or more) micro grips 155 formed in parallel along a common longitudinal axis of outer cannula 155, such that a first micro grip 155A is disposed distal to a second micro grip 155B. Alternatively and / or additionally, and looking now at Fig. 13, if desired, two (or more) micro grips 155 may be arranged radially about a common radial axis of outer cannula 155, such that a first micro grip 155A and a second micro grip 155B are arranged around different longitudinal axes of outer cannula 115, yet in common radial alignment (i.e., such that the tissue mounts 170A, 170B of first micro grip 155A and second micro grip 155B extend radially inwardly around a common radial axis).

[0111] Looking now at Figs. 5 and 7, inner stylet 120 generally comprises a distal end 175, a proximal end 180, and a body 185 extending therebetween. Distal end 175 of inner stylet 120 is preferably sharpened to a cutting point 190, and may comprise a series of sharpened distal edges 195 (e g., three sharpened distal edges 195 forming a tri-facet tip) for facilitating distal movement through tissue, as will hereinafter be discussed in further detail. Body 185 of inner stylet 120 comprises a cross-section that matches the cross-section of lumen 145 of outer cannula 115, such that inner stylet 120 makes a close (but non-binding) fit against the inner surface of sidewall 140 of outer cannula 115 and / or with each micro grip 155 formed in sidewall 140 of outer cannula 115.

[0112] As a result of this construction, when inner stylet 120 is disposed proximally relative to outer cannula 115 such that body 185 of inner stylet 120 does not contact micro grip(s) 155, micro grip(s) 155 “bow” radially inwardly so as to encroach into lumen 145 of outer cannula 115. When outer cannula 115 is moved proximally such that body 185 of inner stylet

[0113] MERMAID-0206120 contacts micro grip(s) 155, body 185 of inner stylet 120 forces the micro grip(s) 155 radially outboard, such that the inner surface (i.e., the surface facing lumen 145) of micro grip(s) 155 are aligned with the inner surface of sidewall 140 of outer cannula 115.

[0114] In a preferred embodiment of the present invention, outer cannula 115 is configured to be selectively slidably moved relative to handle 110 and inner stylet 120. To that end, and looking now at Fig. 5, actuation mechanism 125 comprises appropriate means (e.g., spring-powered, motor driven, etc.) for selectively moving outer cannula 115 distally or proximally so as to cut and capture a tissue sample S, as will hereinafter be discussed in further detail.

[0115] By way of example, but not limitation, and looking now at Figs. 13A and 13B, in another preferred embodiment of the invention there is provided an alternative form of microgrip 155B comprising two tissue mounts 170A, 170B connected together via a resilient tab 172. With this embodiment of the invention, tissue mounts 170A, 170B are formed out of a flexible, resilient material in the shape of “diamond” having a central cutout 173. As a result of this construction, tissue mounts OA, 170B can be configured to deform in the same manner that legs 160, 165 (and tab 172) deform when acted upon by a force. As a result, tissue mounts VOA, 170B provide a “self-elongating” feature that can expand and provide a place for tissue sample S to go when the tab is being pushed inwards (i.e., under the force provided by the resiliency of tab 172 and / or legs 160, 165) when inner stylet 120 is not coincident with tissue mount 155B and hence not forcing tissue 155B outboard.

[0116] It will be appreciated that forming tissue mounts VOA, 170B in a shape (e.g., diamond / parallelogram) having central cutout 173, tissue mounts VOA, 170B are more flexible than if the mounts were rigid

[0117] MERMAID-0206components, allowing for greater flexibility and a greater degree of inward encroachment into lumen 145 / greater inwardly-directed force so as to better grip tissue sample S.

[0118] Method For Performing Biopsy Using

[0119] Novel Biopsy Device 105

[0120] In use, biopsy device 105 is set in a “pre-firing” condition, in which outer cannula 115 is positioned proximally relative to inner stylet 120 such that distal end 175 of inner stylet 120 extends distally beyond distal end 130 of outer cannula 115. In this “pre-firing” condition, biopsy device 105 can be introduced into the anatomy, with cutting point 190 and / or distal cutting edges 195 of inner stylet 120 facilitating distal advancement of inner stylet 120 and outer cannula 115 through tissue to the site of the target tissue from which tissue sample S is to be obtained. Next, and looking now at Fig. 15, outer cannula 115 is moved by the surgeon such that distal end 130 of outer cannula 115 contacts the target tissue T from which a biopsy sample S is to be obtained. It will be appreciated that, due to the relative positioning of inner stylet 120 proximal to the at least one micro grip 155, inner stylet 120 is not in contact with micro grip 155, permitting micro grip 155 to “bow” inwardly so as to encroach upon lumen 145 of outer cannula 115.

[0121] Still looking at Fig. 15, with distal end 130 of outer cannula 115 in contact with target tissue T (or spaced slightly away from target tissue T), outer cannula 115 is moved distally relative to inner stylet 120 via actuation mechanism 125. As outer cannula 115 moves distally and enters into target tissue T, outer cannular 115 “cores out” a tissue sample S in the general shape of a cylinder from target tissue T.

[0122] MERMAID-0206Looking next at Fig. 16, outer cannula 115 moves distally relative to inner stylet 120. As outer cannula 115 is moved distally, tissue sample S is drawn into lumen 145 of outer cannula 115. It will be appreciated that inasmuch as tissue sample S is itself elastically resilient, tissue sample S is momentarily compressed as it is ensheathed by outer cannula 115 and then expands within lumen 145 so as to contact the sidewall 140 of outer cannula 115 and microgrip(s) 155 such that friction between (i) tissue sample S, and (ii) side wall 140 and / or microgrip(s) 155, in combination with the inwardly-directed force provided by microgrip(s) 155 acts to retain tissue sample S within lumen 145.

[0123] Looking next at Fig. 17, as outer cannula 115 is moved distally, contact between body 185 of inner stylet 120 and the at least one micro grip 155 is only maintained until distal end 175 of inner stylet 120 is disposed proximal to the at least one micro grip 155 (i.e., until outer cannula 115 has moved distally beyond distal end 175 of inner stylet 120). Once distal end 175 (and hence, body 185) of inner stylet 120 is disposed proximal to the at least one micro grip 155, the force exerted by body 185 of inner stylet 120 against micro grip 155 is removed, with the result that the at least one micro grip 155 is able to “bow” inwardly so as to encroach upon lumen 145 of outer cannula 115. As a result, tissue sample S, now drawn into lumen 145 (see above) is contacted by the inwardly bowing at least one micro grip 155, whereby to exert traction on tissue sample S and assist in removing the cored-out tissue sample S from target tissue T.

[0124] Looking next at Fig. 18, once tissue sample S is disposed in lumen 145 and maintained in position via traction provided by the at least one micro grip 155, the surgeon then effects rotation of outer cannula 115 about its longitudinal axis, with the result that sharpened, beveled cutting edge 150 of outer cannula 115 shears tissue sample S from target tissue

[0125] MERMAID-0206T. It will be appreciated that rotation of outer cannula 115 may be effected manually (e.g., by the surgeon using handle 110 to rotate outer cannula 115 about its longitudinal axis) or rotation of outer cannula 115 may be effected by an appropriate mechanism contained in handle 110, as will be apparent to one of skill in the art in view of the present disclosure. Outer cannula 115 (containing tissue sample S within lumen 145) is then moved proximally (e.g., via actuation mechanism 125 and / or by removing biopsy device 105 from the anatomy). Tissue sample S can then be removed from lumen 145 and tissue sample S may be collected and examined, as will be apparent to one of skill in the art in view of the present disclosure.

[0126] Novel Biopsy Device Comprising

[0127] Closable Distal End (“M-Bloom”)

[0128] Looking now at Figs. 19-22, there is shown another novel biopsy device 205 formed in accordance with the present invention. Biopsy device 205 generally comprises a handle 210, an outer cannula 215 (Fig.

[0129] 22), an inner cannula 220 (Fig. 22), a stylet 225 (Fig. 22) and an actuation mechanism 230 contained within handle 210 configured to selectively move outer cannula 215 and / or inner cannula 220, as will hereinafter be discussed in further detail.

[0130] More particularly, and looking now at Figs. 22-24, outer cannula 215 comprises a distal end 235, a proximal end 240, and a sidewall 245 enclosing a lumen 250 extending therebetween. Distal end 235 of outer cannula 215 preferably comprises a bevel 255 terminating in a sharpened distal surface 256 for facilitating the coring of tissue, as will hereinafter be discussed in further detail.

[0131] MERMAID-0206A plurality of resilient, flexible leaflets 260 are formed in sidewall 245 of outer cannula 215. Leaflets 260 are configured to be resiliently inwardly biased, so as to encroach upon lumen 250 unless leaflets 260 are forced radially outboard by an outwardly-directed force (e.g., the force resulting from inner cannula 220 contacting leaflets 260 and forcing leaflets 260 outboard so as to align with the remainder of sidewall 245 of outer cannula 215). By way of example but not limitation, outer cannula 215 may comprise stainless steel and / or a shape memory material (e.g., Nitinol, MP35N, Inconel, molybdenum- and / or titanium-containing alloys, super alloys, etc.) with leaflets 260 being formed by one or more cuttings (e.g., laser cuttings) and being treated (e.g., heat-treated) so as to be resiliently inwardly biased towards lumen 250.

[0132] In one preferred form of the present invention, leaflets 260 are treated so as to be inwardly-biased into lumen 250 such that an end 261 (Figs. 22 and 23) of each of the leaflets 260 projects into lumen 250 such that each end 261 of each leaflet 260 is aligned with a central radial axis 266 (Fig. 24) of lumen 250 of outlet cannula 215. As a result of this construction, it will be appreciated that leaflets 260 need not pass through any opening or contact the opposing surface of sidewall 245 when leaflets 260 deflect inwardly into lumen 250 of outer cannula 215.

[0133] In a preferred embodiment of the invention, each of the leaflets 260 are formed by removing a portion of sidewall 245 of outer cannula 215 so as form a cutout 262 (Figs. 22 and 23) extending around a portion of each leaflet 260. By way of example but not limitation, leaflets 260 may be formed by cutting the sidewall 245 of outer cannula 215 using a laser. Such “laser cutting” may employ a laser cutting beam disposed orthogonal to sidewall 245. However, it should be appreciated that, if desired, a laser cutting beam may be disposed at an angle relative to sidewall 245,

[0134] MERMAID-0206whereby to yield leaflets 260 having angled (i.e. , sharpened) edges that facilitate shearing of tissue, as will be apparent to one of skill in the art in view of the present disclosure. Cutout 262 is formed so as to be disposed proximal to distal end 235 of outer cannula 215, whereby to provide an intact, circumferentially-extending portion 263 of sidewall 245 disposed immediately proximal to bevel 255. See also Fig. 23A showing outer cannula 215 with intact, circumferentially-extending portion 263 comprising a bevel 255A extending a first distance di to distal cutting surface 256, and Fig. 23B showing outer cannula 215 comprising a bevel 255B extending a second distance d2 to distal cutting surface 256, with di < d2. It will be appreciated that, if desired, bevel 255 may extend proximally a sufficient distance to encompass a portion of one or more of leaflets 260. By way of example but not limitation, material may be removed from sidewall 245 of outer cannula 215 and a portion of leaflets 260 such that each end 261 of each of leaflets 260 is thinner than the remaining portion of each of leaflets 260.

[0135] If desired, in another form of the invention, and looking now at Figs.

[0136] 23C and 23D, leaflets 260 may be formed with varying lengths, i.e., such that end 261 A of a first leaflet 260A is disposed farther from distal surface 255 than end 261 B of a second leaflet 260B. It will be appreciated that, as a result of the foregoing construction, leaflet 260B extends farther into lumen 250 than leaflet 260A, whereby to produce a “scissoring action” between leaflet 260A and leaflet 260B as the leaflets deflect inwardly into lumen 250. This “scissoring action” can assist in separating (i.e., shearing) tissue sample S from the native tissue, as will hereinafter be discussed in further detail.

[0137] Although only two leaflets 260A, 260 are depicted in Figs. 23C and 23D, it should be appreciated that the present invention encompasses

[0138] MERMAID-0206configurations of outer cannula 215 comprising three (or more) leaflets 260 having different / identical lengths, and being staggered across the circumference of sidewall 245 of outer cannula 215. Furthermore, inasmuch as leaflets 260 are machined from a very thin material, it should be appreciated that any / all of the side surfaces of each leaflet 260 may be “sharp” enough to cut tissue (or may be intentionally sharpened by an appropriate laser cutting machining process, see above) whereby to enhance showing of tissue sample S from the native tissue, as will be apparent to one of the skill in the art in view of the present disclosure.

[0139] Looking now at Figs. 23-25, inner cannula 220 comprises a distal end 265, a proximal end 270, and a lumen 275 extending therebetween. Distal end 265 of inner cannula 220 preferably terminates in a beveled distal cutting surface configured to core tissue, as will hereinafter be discussed in further detail. Inner cannula 220 is sized to be slidably received within lumen 250 of outer cannula 215, such that inner cannula 220 can be selectively moved relative to outer cannula 215 (and / or such that outer cannula 215 can be selectively moved relative to inner cannula 220), as will hereinafter be discussed in further detail.

[0140] Looking now at Fig. 26, stylet 225 comprises a rod 280 having a distal end 285 and a proximal end 290 fixedly mounted to handle 210. Distal end 285 of stylet 225 comprises a distal tip 295 configured to facilitate navigation of biopsy device 205 through intervening tissue to the target site from which tissue sample S is to be obtained, as will be apparent to one of skill in the art in view of the present disclosure.

[0141] In a preferred form of the invention, proximal end 290 of stylet 225 is fixedly mounted to handle 210, proximal end 270 of inner cannula 220 is mounted to actuation mechanism 230 so as to be coaxially disposed and selectively slidable relative to stylet 225, and proximal end 240 of outer

[0142] MERMAID-0206cannula 215 is mounted to actuation mechanism 230 so as to be coaxially disposed and selectively slidable relative to inner cannula 220, as will hereinafter be discussed in further detail.

[0143] Novel Actuation Mechanism

[0144] Looking now at Figs. 27-31 , in a preferred embodiment of the invention, handle 210 comprises novel actuation mechanism 230 for moving a first element (e.g., inner cannula 220) relative to a fixed element (e.g., stylet 225) a first distance, and simultaneously (or nearly simultaneously) moving a second element (e.g., outer cannula 215) relative to the first element a second distance.

[0145] More particularly, in a preferred embodiment of the invention, stylet 225 is fixedly mounted to handle 210 and extends a first distance distally relative to handle 210. Inner cannula 220 is coaxially disposed over stylet 225 such that stylet 225 is disposed in lumen 275 of inner cannula 225, with proximal end 270 of inner cannula 220 being mounted to actuation mechanism 230 such that inner cannula 220 can be selectively moved distally so as to extend a second distance distally relative to handle 210. Outer cannula 215 is coaxially disposed over inner cannula 220 such that inner cannula 220 is disposed in lumen 250 of outer cannula 215, with proximal end 240 of outer cannula 215 being mounted to actuation mechanism 230 such that outer cannula 215 can be selectively moved distally so as to extend a third distance distally relative to handle 210. It will be appreciated that the third distance is preferably greater than the second distance, and the second distance is preferably greater than the first distance. In a preferred form of the invention, when inner cannula 220 and outer cannula 215 are both disposed in their proximalmost positions, respectively, distal tip 295 of stylet 225 extends distal to both distal end

[0146] MERMAID-0206result of this construction, when inner cannula 220 and outer cannula 215 are both moved to their respective distalmost positions by actuation mechanism 230, the distal end of outer cannula 215 is disposed distal to the distal end 265 of inner cannula 220, and the distal end 265 of inner cannula 220 is disposed distal to the distal tip 295 of stylet 225.

[0147] Still looking now at Figs. 27-31, actuation mechanism 230 generally comprises a carriage limiter 300, a first carriage 305, a second carriage 310, a trigger 315, a deployment spring 320, and an arming mechanism 325.

[0148] Carriage limiter 300 comprises a distal portion 330 having a carriage cavity 335 formed therein, and a proximal portion 340 having a selectively slidable toggle element 345 for selectively moving carriage limiter 300 distally (or proximally) relative to handle 210, whereby to permit control over the travel distance of first carriage 305 and second carriage 310, and hence, control over the distal travel distance of inner cannula 220 and outer cannula 215, respectively, as will hereinafter be discussed in further detail. Carriage cavity 335 of distal portion 330 of carriage limiter 300 comprises a pair of stops 350, 355 disposed proximal to a distal end stop 360 of carriage cavity 335.

[0149] First carriage 305 is mounted to inner cannula 220 such that when first carriage 305 moves distally relative to handle 210, inner cannula 220 moves distally relative to handle 210 the same distance that first carriage 305 moves distally. First carriage 305 is configured to be selectively moved distally in carriage cavity 335, under the power of deployment spring 320, until first carriage 305 contacts stops 350, 355 and distal movement of first carriage 305 is halted, as will hereinafter be discussed in further detail. Second carriage 310 is mounted to outer cannula 215

[0150] MERMAID-0206such that when second carriage 310 moves distally relative to handle 210, outer cannula 215 moves distally relative to handle 210 the same distance that second carriage 310 moves distally. Second carnage 310 is configured to be selectively moved distally in carriage cavity 335, under the power of deployment spring 320, until second carriage 310 contacts distal end stop 360 of carriage cavity 335, as will hereinafter be discussed in further detail.

[0151] Trigger 315 comprises a push button 365 and a carriage-retaining rocker 370. Rocker 370 comprises a pair of selectively-pivotable arms 375. Push button 365 is configured to selectively pivot arms 375 of rocker 370 when push button 365 is actuated (i.e. , depressed), whereby to pivot arms 375 so as to release first carriage 305 and second carriage 310, with the result that the carriages are able to move distally under the power of deployment spring 320, as will hereinafter be discussed in further detail. It will also be appreciated that, if desired, a push button may be provided at the proximalmost surface of handle 210 comprising an appropriate mechanical linkage to selectively actuate trigger 315 when the push button at the proximalmost surface of handle 210 is actuated, as will be apparent to one of skill in the art in view of the present disclosure.

[0152] Looking now at Figs. 28-30, deployment spring 320 is disposed between the proximal end of first carriage 305 and a fixed stop 380 mounted to handle 210. As a result of this construction, when first carriage 305 and second carriage 310 are disposed in a first, proximal, “armed” position in which arms 375 of rocker arm 370 engage carriages 305, 310, deployment spring 320 is compressed between the proximal end of first carriage 305 and stop 380. When first carriage 305 and second carriage 310 are released by moving arms 375 of rocker arm 370, deployment spring 320 forces first carriage 305 and second carriage 310

[0153] MERMAID-0206distally. When first carriage 305 thereafter contacts stops 350, 355, second carriage 310 continues moving distally in carriage cavity 335 under the power of inertia imparted by first carriage 305 / deployment spring 320 until the distal end of second carriage 310 contacts distal end stop 360 of carriage cavity 335. See Fig. 31 , which shows first carriage 305, second carriage 310, and deployment spring 320 in a “deployed” configuration.

[0154] If desired, and looking now at Fig. 32, a second spring 385 may be provided disposed between the distal end of first carriage 305 and the proximal end of second carriage 310. As a result of this construction, when first carriage 305 moves distally until further distal movement is halted by stops 350, 355, second spring 385 acts to (i) impart a small distally-directed force to second carriage 310 to ensure that second carriage 310 moves fully distally to contact distal end stop 360 of carriage limiter 300, and (ii) maintains outer cannula 215 in its fully deployed, distalmost position. Thus, second spring 385 acts to both ensure proper distal movement of outer cannula 215 relative to inner cannula 220, and assists in maintaining outer cannula 215 in its distalmost position, such that distal end 235 of outer cannula 215 extends distally beyond distal end 265 of inner cannula 220, with the result that leaflets 260 of outer cannula 215 are permitted to deflect radially inboard into lumen 250 of outer cannula 215, whereby to assist in maintaining a sample of cored tissue within lumen 275 of inner cannula 220, as will hereinafter be discussed in further detail.

[0155] Looking now at Figs. 19-21 and 27-29, arming mechanism 325 comprises an arming handle 390 mounted to handle 210 and configured to selectively slide relative thereto, and an arming slide 395 slidably mounted within a slot 400 formed in handle 210 and configured to slide

[0156] MERMAID-0206relative to handle 210. Arming slide 395 is mounted to arming handle 390 such that proximal movement of arming handle 390 effects proximal movement of arming slide 395. Arming slide 395 comprises a proximal end (not shown) and a distal end terminating in a pawl 405. Pawl 405 is configured to rest distal to, or against distal end stop 360 of carriage limiter 300 when arming handle 390 is disposed in a distalmost position. Pawl 405 extends orthogonal to the longitudinal axis of slide 395 so as to encroach into carriage cavity 335, whereby to contact and engage second carriage 310 when arming slide 395 is moved proximally. As a result of this construction, when arming handle 390 is moved proximally, arming slide 395 also moves proximally within slot 400. As arming slide 395 moves proximally within slot 400, pawl 405 contacts second carriage 310 and moves second carriage 310 proximally in concert with proximal movement of arming slide 395. The proximal end of second carriage 310 contacts the distal end of first carriage 305, causing first carriage 305 to also move proximally in concert with proximal movement of arming slide 395, against the power of deployment spring 320, thereby storing energy in deployment spring 320 (and, if provided, storing energy in second spring 385). As arming slide 395 reaches its proximalmost position, first carriage 305 and second carriage 310 contact arms 375 of rocker arm 370 of trigger 315, causing arms 375 to momentarily pivot to accommodate second carriage 310 once second carriage 310 is disposed sufficiently proximal for arms 375 to pivot downward in front of the distal surface of second carriage 310, whereby to releasably retain second carriage 310 in a proximal position against the force of deployment spring 320. If desired, a return spring (not shown) may be provided to bias arming handle 390 distally such that arming handle 390 returns to a distalmost position after being moved proximally in the manner discussed above.

[0157] MERMAID-0206It will be appreciated that arming handle 390 provides significant leverage for the surgeon to “arm” actuation mechanism 230. Specifically, arming handle 390 extends over and about a distal portion of handle 210, providing the surgeon with a large structure to grasp and pull back against the force of deployment spring 320 and / or second spring 385.

[0158] Furthermore, arming handle 390 is preferably formed as a solid structure that prevents the inadvertent ingress of blood / bodily fluids into the interior of handle 210, and also preferably comprises a textured surface to facilitate gripping of arming handle 390. Thus, arming handle 390 is a significant improvement over thumb sliders and / or plungers.

[0159] Looking now at Figs. 27-29, if desired, actuation mechanism 230 may further comprise a safety toggle switch 410. Switch 410 comprises a pawl 415 which can be moved by actuating switch 410 such that pawl 415 selectively disengages / engages trigger 315, with the result that trigger 315 can be (i) actuated by pressing push button 365 when pawl 415 is disposed in a first, i.e. , “unlocked” position, or (ii) locked against actuation by preventing push button 365 from being depressed when pawl 415 is disposed in a second, i.e., “locked” position.

[0160] Looking now at Figs. 19-28, if desired, toggle element 345 may be used to selectively adjust the position of carriage limiter 300 relative to handle 210, whereby to selectively adjust the distance that first carriage 305 and second carriage 310 move distally relative to handle 210 (and hence, to control the distance that inner cannula 220 and outer cannula 215 move distally relative to handle 210). More particularly, toggle element 345 is mounted to proximal portion 340 of carriage limiter 300, whereby to permit a user to move proximal portion 340 of carriage limiter 300 (and hence, distal portion 330 of carriage limiter 300) relative to handle 210. Proximal portion 340 of carriage limiter 300 preferably

[0161] MERMAID-0206comprises a plurality of resilient detents (or pawls) 420 for engaging counterpart resilient pawls (or detents) (not shown) formed on a surface of handle 210, as will be apparent to one of skill in the art in view of the present disclosure. As a result of this construction, it is possible to move toggle element 345 against the resilient power of detents (or pawls) 420 a discrete distance (e.g., one detent / pawl distally, two detents / pawls distally, etc.) so as to selectively adjust the positioning of carriage cavity 335.

[0162] Thus, it will be appreciated that, as toggle element 345 is moved distally a set distance (e.g., one pawl distal), carriage cavity 335 is also moved distally the same distance. As a result, it is possible to set the distal position of stops 350, 355 and distal end stop 360 so as to control the distance that first carriage 305 and second carriage 310 are able to move distally. And, as a result, it is possible to control the distance of distal movement of inner cannula 220 and outer cannula 215.

[0163] It should be appreciated that in some circumstances, it may be desirable to ensure that outer cannula 215 is moved distally via movement of second carriage 310 distally with a predetermined amount of force. Moreover, it should be appreciated that even where second spring 385 is provided to assist in moving second carriage 310 distally after movement of first carriage 305 has been halted (i.e., by engagement of first carriage 305 with stops 350, 355, see above), some of the force provided by second spring 385 is lost during the initial movement of second carriage 310 unless spring 385 remains compressed until first carriage 305 actually engages stops 350, 355. Thus, it may be advantageous to provide a secondary trigger mechanism configured to keep second spring 385 compressed until first carriage 305 engages stops 350, 355, such that the full force of second spring 385 can be applied to second carriage 310 to move second carriage 310 into engagement with distal end stop 360 (and

[0164] MERMAID-0206maintain second carriage 310 in a fully-distally-deployed configuration). Furthermore, where first carriage 305 and second carriage 310 tend to move in concert, two additional issues may manifest: (i) outer cannula 215 (mounted to second carriage 310) may move to its distalmost position too quickly, with the result that leaflets 260 tend to close down over inner cannula 220 rather than shearing tissue sample S from the native tissue, and / or (ii) there is insufficient force provided by second spring 335 to maintain leaflets 260 distal to inner cannula 220 so as to close down lumen 220 and retain tissue sample S therein.

[0165] To address the foregoing, and looking now at Figs. 33, 34A, 34B, 36, 37A, 37B, and 38-40, in another embodiment of the present invention there is provided a novel actuation mechanism 230A. Actuation mechanism 230A is substantially identical to the aforementioned actuation mechanism 230, except that (i) with actuation mechanism 230A, there is provided a carriage limiter 300A having a different configuration than the aforementioned carriage limiter 300, and (ii) with actuation mechanism 230A, there is provided a second carriage 310A modified to retain the stored force within second spring 385 until second carriage 310A is moved to a predetermined position within carriage limiter 300A, as will hereinafter be discussed in more detail.

[0166] More particularly, with this embodiment of the invention, and looking now at Figs. 33 and 35, carriage limiter 300A comprises a pair of grooves 425, 430 facing carriage cavity 335 and opening thereon. Groove 425 comprises a pocket 435 formed in the distal region of groove 425 which extends outboard (i.e., in a direction orthogonal to the longitudinal axis of handle 210), and groove 430 comprises a pocket 440 formed in the distal region of groove 430 which extends outboard (i.e., in a direction orthogonal to the longitudinal axis of handle 210). Second carriage 310A

[0167] MERMAID-0206of carriage limiter 300A comprises a generally cylindrical body 445 having a distal end 450 and a proximal end 455. A radially-reduced region 460 (Figs. 35, 36, 37A, 37B, and 38) is formed in body 445 intermediate distal end 450 and proximal end 455.

[0168] A pair of bearing components 465 are disposed on either side of second carriage 310A. Each bearing component 465 comprises a body 470 having a first end 475 configured to be received in groove 425 and / or pocket 435 (or groove 430 and / or pocket 440), and a second end 480 configured to be received in radially-reduced region 460 of body 445 of second carriage 310A when second carriage 310A is disposed in a proximal position, as will hereinafter be discussed in further detail. More particularly, first end 475 and second end 480 of each bearing component 465 prefereably comprises a rotatable, spherical component (e.g., a ballbearing) for reducing friction between (i) bearing component 465 and grooves 425, 430 (or pockets 435, 440), and (ii) bearing component 465 and radially-reduced region 460 of body 445 of second carriage 310A. In one preferred form of the invention, each bearing component 465 comprises at least one spherical ball bearing encased in a cylindrical sleeve such that the bearing at first end 475 and second end 480 is halfway exposed and able to rotate freely, as will be apparent to one of skill in the art in view of the present disclosure. It should be appreciated that, if desired, multiple spherical bearings (e.g., three bearings) may be disposed in a cylindrical sleeve to achieve the same result, as will be apparent to one skilled in the art in view of the present disclosure.

[0169] Radially-reduced region 460 of body 445 of second carriage 310A is preferably slightly less than one-half of the diameter of the bearing portion of second end 480 of bearing component 465. Bearing components 465 are sized such that when bearing component 465 is disposed so as to

[0170] MERMAID-0206extend between radially-reduced region 460 of body 445 of second carriage 310A and groove 425 (or groove 430) of carriage limiter 300A, second spring 385 is unable to move second carriage 310A distally. Other configurations for bearing components 465 will be apparent to one of skill in the art in view of the present disclosure and fall within the scope of the present invention.

[0171] With actuation mechanism 230A, as first carriage 305 and second carriage 310A are driven distally under the power of deployment spring 320, second spring 385 remains compressed because bearing components 465 extend between radially-reduced region 460 of body 445 of second carriage 310A and prevents second carriage 310A from moving distally under the power of second spring 385. It will be appreciated that, since second carriage 310A has not yet moved distally beyond first carriage 305, leaflets 260 are disposed in alignment with side wall 245 of outer cannula 215 and do not encroach into lumen 250 (hence, a tissue sample S may be passed into lumen 275 of inner cannula 220 without interference from leaflets 260). However, when second carriage 310A is moved sufficiently distally (i.e. , under the power of deployment spring 320) such that first end 475 of each bearing component 465 enters into laterally-enlarged pockets 435, 440 of grooves 425, 430, respectively, the force of second spring 385 is then sufficient to push second end 480 of each bearing component out of radially-reduced region 460 of body 445 of second carriage 310, whereby to permit second carriage 310A to move distally under the power of second spring 385 (and / or partially still under the power of deployment spring 320) until second carriage 310A engages distal end stop 360. As a result, distal end 235 of outer cannula 215 moves distally beyond distal end 265 of inner cannula 220 with leaflets 260 disposed distally beyond distal end 265 of inner cannula. This

[0172] MERMAID-0206permits leaflets 260 to move inboard under the force of their own resiliency so as to shear tissue sample S and close off the distal ends of lumens 250, 275, retaining tissue sample S therein. Moreover, the force of second spring 385 holding second carriage 310A in its distalmost position ensures that outer cannula 215 remains in its distalmost position with leaflets 260 encroaching into lumen 250.

[0173] Thus it will be appreciated that, with actuation mechanism 230A, it is possible to control the timing of release of the force of second spring 385 by controlling the disposition of pockets 435, 440 (i.e. , by disposing pockets 435, 440 more proximally, it is possible to release the force of second spring 385 sooner; by disposing pockets 435, 440 more distally, it is possible to delay the release of the force of second spring 385 until later during actuation). Thus, actuation mechanism 230A permits precise control over the timing of movement of outer cannula 215 over inner cannula 220.

[0174] Additionally, it will be appreciated that actuation mechanism 230A constitutes a “self-locking” feature once actuated. That is, once first end 475 of each bearing component 465 is disposed in laterally-enlarged pockets 435, 440 of grooves 425, 430, respectively, outer cannula 215 is disposed at its distalmost position, with leaflets 260 encroaching into, and cutting off, lumen 250. Outer cannula 215 is locked against proximal movement relative to inner cannula 220 by the force of second spring 385 and the disposition of bearing components 465 in laterally-enlarged pockets 435, 440. This prevents accidental ejection of tissue sample S out of lumen 275 (or lumen 250) as biopsy device 205 is removed from the anatomy. When it is desired to eject tissue sample S out of lumens 275, 250 (i.e., to collect tissue sample S for pathologic examination), the surgeon must pull back arming handle 390 against the power of second

[0175] MERMAID-0206spring 385, whereby to move second carriage 31 OA proximally such that second end 480 of each bearing component 465 is moved back into radially-reduced region 460 of second carriage 31 OA and first end 475 of each bearing component 465 is disposed in grooves 425, 430. Thus, actuation mechanism 230A also works in “reverse” to ensure correct timing of movement of outer cannula 215 relative to inner cannula 220 so as to protect tissue sample S from being damaged as it is collected for pathologic examination.

[0176] Use Of Novel Biopsy Device 205

[0177] In use, biopsy device 205 is deployed as follows. First, the surgeon “arms” biopsy device 205 by moving arming slide 395 proximally so as to move carriages 305, 310 proximally against the power of deployment spring 320. Once carriages 305, 310 have been moved proximally so as to be engaged by arms 375 of rocker arm 370 of trigger 315, carriages 305, 310 are held in position by arms 375 until the surgeon actuates push button 365.

[0178] Once biopsy device 205 is in the “armed” position discussed above, the distal ends 235 and 265 of outer cannula 215 and inner cannula 220 are disposed proximal to distal end 285 of stylet 225, whereby to expose distal tip 295 of stylet 225.

[0179] The surgeon then moves biopsy device 205 relative to the anatomy from which a tissue sample S is to be obtained. By moving handle 210 distally at the desired location in the anatomy, the surgeon advances stylet 225 distally into the tissue from which tissue sample S is to be obtained.

[0180] Holding handle 210 in position, the surgeon then actuates push button 365 of trigger 315 (e.g., by pressing push button 365). Actuation of push button 365 engages (i.e. , “causes”) rocker arm 370 to pivot such that

[0181] MERMAID-0206arms 375 disengage from second carriage 310 (or from first carriage 305). As a result, first carriage 305 and second carriage 310 are released and move distally under the power of deployment spring 320, within carriage cavity 335 moving both inner cannula 220 (mounted to first carriage 305) and outer cannula 215 (mounted to second carriage 310) distally simultaneously.

[0182] As this occurs, inner cannula 220 and outer cannula 215 move distally, with inner cannula 220 sliding over distal tip 295 of stylet 225 and surrounding and coring out tissue sample S that is to be extracted from the anatomy.

[0183] When first carriage 305 contacts stops 350, 355 of carriage cavity 335, distal movement of carriage 305 (and hence, of inner cannula 220) is halted. However, second carriage 310 continues to move distally under inertia (or, if second spring 385 is provided, under the combined power of inertia and the power of second spring 385) until second carriage 310 contacts distal end stop 360 of carriage cavity 335. Thus, distal end 235 of outer cannula 215 moves distally a set distance beyond distal end 265 of inner cannula 220. Note that where actuation mechanism 230A is provided, movement of first carriage 305 and second carriage 305A is substantially the same, however, the force of second spring 385 does not force second carriage 305A distally until bearing components 465 are disposed in laterally-extending pockets 435, 440 in the manner discussed above.

[0184] It will be appreciated that as distal end 235 of outer cannula 215 moves distally beyond distal end 265 of inner cannula 220, inner cannula 220 is no longer contacting inwardly-biased leaflets 260 of distal end 235 of outer cannula 215. Thus, leaflets 260 of outer cannula 215 deflect inboard so as to encroach upon and / or close off lumen 250 (and lumen

[0185] MERMAID-0206275) at a position distal to distal end 265 of inner cannula 220. The additional column strength provided by bevel 255 of outer annual 215 helps to ensure that leaflets 260 are not compromised (e.g., bent) by distal movement into the tissue, and assists in maintaining the integrity of an open lumen 250 for leaflets 260 to deflect into. As a result, leaflets 260 act to close off lumen 250 just proximal to distal end 235 of outer cannula 215, and just distal to distal end 265 of inner cannula 215, whereby to assist in maintaining tissue sample S within lumen 275 of inner cannula 220.

[0186] With tissue sample S disposed in lumen 275 and leaflets 260 cooperating to close off lumen 275 of inner cannula 220, the surgeon can retract handle 210 proximally, carrying tissue sample S contained in lumen 275. The tissue sample S can then be ejected out of lumen 275 into an appropriate container in a manner that will be apparent to one of skill in the art in view of the present disclosure. By way of example but not limitation, tissue sample S may be removed from lumen 275 by moving arming slide 395 proximally so as to proximally retract inner cannula 220 and outer cannula 215, whereby to expose tissue sample S (while simultaneously forcing leaflets 260 outboard as outer cannula 215 and leaflets 260 move proximally over distal end 265 of inner cannula 220).

[0187] Modifications Of The Preferred Embodiments It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.

[0188] MERMAID-0206

Claims

What Is Claimed Is:

1. Apparatus for obtaining a tissue sample from tissue, said apparatus comprising:a handle having a distal end, a proximal end, and a cavity extending therebetween;a stylet comprising a distal end and a proximal end, said stylet extending distally from the distal end of said handle;an inner cannula comprising a distal end, a proximal end, and a sidewall enclosing a lumen extending therebetween, said inner cannula being disposed coaxial to said stylet;an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said inner cannula;an actuation mechanism disposed in said cavity of said handle, said actuation mechanism being configured to (i) selectively move said inner cannula relative to said stylet, and (ii) selectively move said outer cannula relative to said inner cannula and said stylet;wherein said distal end of said outer cannula comprises a sharpened distal surface, and further wherein said outer cannula comprises at least one leaflet disposed proximal to said sharpened distal surface;and further wherein said at least one leaflet is configured to move from a first position, in which said at least one leaflet is coincident with said side wall of said outer cannula and does not encroach upon said lumen of said outer cannula to a second position in which said at least one leaflet is not coincident with said side wall of said outer cannula and encroaches upon said lumen of said outer cannula.MERMAID-02062. The apparatus of claim 1 wherein said at least one leaflet comprises a shape memory material.

3. The apparatus of claim 2 wherein said shape memory material comprises one selected from the group consisting of Nitinol, stainless steel, MP35N and Inconel.

4. The apparatus according to claim 2 wherein said shape memory material is flexible and resilient, such that said at least one leaflet is in said second position unless acted upon by a force.

5. The apparatus according to claim 4 wherein said at least one leaflet is disposed in said first position when said leaflet contacts said sidewall of said inner cannula, and said at least one leaflet is disposed in said second position when said at least one leaflet does not contact said sidewall of said inner cannula.

6. The apparatus of claim 1 wherein said outer cannula comprises a plurality of leaflets arranged radially about said outer cannula so as to cooperate to substantially close-off said lumen of said outer cannula when said plurality of leaflets are disposed in said second position.

7. The apparatus of claim 1 wherein said stylet is fixed in position relative to the handle.MERMAID-02068. The apparatus of claim 1 wherein said actuation mechanism is configured to move said inner cannula and said outer cannula from (i) an undeployed position in which said distal end of said inner cannula and said distal end of said outer cannula are disposed proximal to said distal end of said stylet, and said at least one leaflet is disposed in said first position, to (ii) a deployed position in which said distal end of said inner cannula is disposed distal to said distal end of said stylet, said distal end of said outer cannula is disposed distal to said distal end of said inner cannula, and said at least one leaflet is disposed in said second position.

9. The apparatus of claim 8 wherein, when said inner cannula and said outer cannula are moved from said undeployed position to said deployed position, said distal end of said inner cannula reaches a distalmost position prior to said distal end of said outer cannula reaching a distalmost position.

10. The apparatus of claim 8 wherein said actuation mechanism is further configured to selectively move said inner cannula and said outer cannula from said deployed position to said undeployed position, and further wherein after said inner cannula and said outer cannula are moved from said deployed position to said undeployed position: (i) said distal end of said inner cannula and said distal end of said outer cannula are disposed proximal to said distal end of said stylet, and (ii) said distal end of said outer cannula is moved proximally before said distal end of said inner cannula is moved proximally.

11. The apparatus of claim 1 wherein said actuation mechanism comprises:MERMAID-0206a carriage limiter comprising:a carriage cavity mounted to said handle, said carriage cavity comprising a proximal end and a distal end;at least one groove extending between said proximal end and said distal end, said at least one groove comprising a laterally-extending pocket extending orthogonal to a longitudinal axis of said at least one groove; andat least one proximal stop and at least one distal stop disposed distal to said at least one proximal stop;a first carriage mounted to said inner cannula, said first carriage being disposed in said carriage cavity;a second carriage mounted to said outer cannula, said second carriage comprising a radially-reduced region;a deployment spring having a first end mounted to said handle and a second end contacting said first carriage so as to bias said first carriage distally;a second spring having a first end mounted to said first carriage and a second end contacting said second carriage;at least one bearing having a first end slidably received in said groove of said carriage limiter and a second end received in said radially-reduced region of said second carriage;a trigger for (i) selectively restraining said first carriage and said second carriage in a proximal position in said carriage cavity against the power of said deployment spring, and (ii) selectively releasing said first carriage such that said first carriage and said second carriage move distally within said carriage cavity under the power of said deployment spring until said first carriage contacts said at least one proximal stop;MERMAID-0206wherein said at least one bearing prevents said second carriage from moving distally within said carriage cavity under the power of said second spring until said first end of said at least one bearing is received within said laterally-extending pocket of said groove, and wherein said at least one bearing permits said second carriage to move distally within said carriage cavity under the power of said second spring when said first end of said at least one bearing is received within said laterally-extending pocket of said groove and said second end of said bearing moves out of said radially-reduced region of said second carriage under the power of said second spring; andwherein when said first carriage contacts said at least one proximal stop, said first carriage is halted while said second carriage continues to move distally until said second carriage contacts said at least one distal stop.

12. The apparatus of claim 8 wherein said actuation mechanism comprises a trigger, and further wherein actuation of said trigger causes said actuation mechanism to move said inner cannula and said outer cannula from said undeployed position to said deployed position.

13. The apparatus of claim 12 wherein:said actuation mechanism comprises:a carriage limiter defining a carriage cavity;a first carriage disposed in said carriage cavity and mounted to said proximal end of said inner cannula; anda second carriage disposed in said carriage cavity and mounted to said proximal end of said outer cannula;MERMAID-0206at least one proximal stop for halting distal movement of said first carriage within said carriage cavity;at least one distal stop for halting distal movement of said second carriage within said carriage cavity;a spring mounted to said handle, said spring being configured to effect movement of said first carriage and said second carriage within said carriage cavity.

14. The apparatus according to claim 13 wherein, when said trigger is actuated, said first carriage and said second carriage move distally within said carnage cavity.

15. The apparatus according to claim 14 wherein said first carriage moves distally until said first carriage contacts said proximal stop, and said second carriage moves distally until said second carriage contacts said distal stop.

16. A method for obtaining a tissue sample from tissue, said method comprising:providing apparatus comprising:a handle having a distal end, a proximal end, and a cavity extending therebetween;a stylet comprising a distal end and a proximal end, said stylet extending distally from the distal end of said handle;an inner cannula comprising a distal end, a proximal end, and a sidewall enclosing a lumen extending therebetween, said inner cannula being disposed coaxial to said stylet;MERMAID-0206an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said inner cannula;an actuation mechanism disposed in said cavity of said handle, said actuation mechanism being configured to (i) selectively move said inner cannula relative to said stylet, and (ii) selectively move said outer cannula relative to said inner cannula and said stylet;wherein said distal end of said outer cannula comprises a sharpened distal surface, and further wherein said outer cannula comprises at least one leaflet disposed proximal to said sharpened distal surface;and further wherein said at least one leaflet is configured to move from a first position, in which said at least one leaflet is coincident with said side wall of said outer cannula and does not encroach upon said lumen of said outer cannula to a second position in which said at least one leaflet is not coincident with said side wall of said outer cannula and encroaches upon said lumen of said outer cannula;advancing said handle distally until said distal end of said inner cannula is disposed against the tissue that is to be sampled;actuating said actuation mechanism so as to (i) move said inner cannula and said outer cannula distally such that said inner cannula moves distally over the tissue sample and the tissue sample is received in said lumen of said inner cannula, and (ii) move said outer cannula distally such that said at least one leaflet is in said second position.

17. Apparatus for selectively moving a first object relative to a second object, said apparatus comprising:a handle;MERMAID-0206a carriage limiter comprising:a carriage cavity mounted to said handle, said carriage cavity comprising a proximal end and a distal end;at least one groove extending between said proximal end and said distal end, said at least one groove comprising a laterally-extending pocket extending orthogonal to a longitudinal axis of said at least one groove; andat least one proximal stop and at least one distal stop disposed distal to said at least one proximal stop;a first carriage mounted to a first object, said first carriage being disposed in said carriage cavity;a second carriage mounted to a second object, said second carriage being disposed in said carriage cavity distal to said first carriage, wherein said second carriage comprises a radially-reduced region;a deployment spring having a first end mounted to said handle and a second end contacting said first carriage so as to bias said first carriage distally;a second spring having a first end mounted to said first carriage and a second end contacting said second carriage;at least one bearing having a first end slidably received in said groove of said carriage limiter and a second end received in said radially-reduced region of said second carriage;a trigger for (i) selectively restraining said first carriage and said second carriage in a proximal position in said carriage cavity against the power of said deployment spring, and (ii) selectively releasing said first carriage such that said first carriage and said second carriage move distally within said carriage cavity under the power of said deployment spring until said first carriage contacts said at least one proximal stop;MERMAID-0206wherein said at least one bearing prevents said second carriage from moving distally within said carriage cavity under the power of said second spring until said first end of said at least one bearing is received within said laterally-extending pocket of said groove, and wherein said at least one bearing permits said second carriage to move distally within said carriage cavity under the power of said second spring when said first end of said at least one bearing is received within said laterally-extending pocket of said groove and said second end of said bearing moves out of said radially-reduced region of said second carriage under the power of said second spring; andwherein when said first carriage contacts said at least one proximal stop, said first carriage is halted while said second carriage continues to move distally until said second carriage contacts said at least one distal stop.

18. The apparatus of claim 17 wherein said first object comprises a first end and a second end, said second object comprises a first end and a second end, and further wherein, when said first carriage is in a distalmost position within said carriage cavity and said second carriage is in a distalmost position within said carriage cavity, said second end of said second object extends beyond said second end of said first object.

19. The apparatus of claim 17 wherein said trigger comprises a rocker having at least one arm, and further wherein said at least one arm of said rocker is configured to contact at least one of said first carriage and said second carriage and maintain said at least one of said first carriage and second carriage in a proximal position within said carriage cavityMERMAID-0206against the power of said deployment spring when said trigger is in a first position, and wherein said at least one arm of said rocker is configured to pivot such that said at least one arm of said rocker does not contact either said first carriage or said second carriage when said trigger is in a second position.

20. The apparatus of claim 17 further comprising an arming handle configured to be selectively moved relative to said handle, and further wherein proximal movement of said arming handle effects proximal movement of said second carriage and said first carriage within said carriage cavity against the power of said deployment spring.

21. The apparatus of claim 17 wherein said carriage limiter is configured to be selectively moved relative to said handle such that said carriage cavity can be selectively moved relative to said first carriage and said second carriage.

22. The apparatus of claim 19 further comprising a safety toggle switch, wherein when said safety toggle switch is in a locked position said trigger is locked against movement from said first position to said second position, and when said safety toggle switch is in a released position, said trigger is able to move from said first position to said second position.

23. Apparatus for obtaining a tissue sample from tissue, said apparatus comprising:a handle;a stylet comprising a proximal end and a distal end, said proximal end of said stylet being mounted to said handle;MERMAID-0206an outer cannula comprising a distal end, a proximal end, and a sidewall defining a lumen extending therebetween, said outer cannula being disposed coaxial to said stylet such that said stylet extends through said lumen of said outer cannula;at least one microgrip formed in said sidewall of said outer cannula, said at least one microgrip being configured to (i) bow inwardly so as to encroach upon said lumen of said outer cannula when said at least one microgrip is not in contact with said stylet, and (ii) be coincident with a plane defined by said sidewall of said outer cannula when said at least one microgrip is in contact with said stylet.MERMAID-0206

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