Introducer cannula having a tissue anchor for use with a medical instrument

An introducer cannula configured for receiving a medical instrument includes a cannula tube having a side wall surrounding a central lumen, a proximal end, and a distal end. An elongate tissue anchor is positioned in the central lumen of the cannula tube. The elongate tissue anchor has a mounting end and an anchoring free end. The elongate tissue anchor is movable in the central lumen such that the anchoring free end is movable between a retracted position and a deployed position. An actuator is coupled to the proximal end of the cannula tube. The actuator is coupled to the mounting end of the elongate tissue anchor. The actuator is operatively configured to selectively position the anchoring free end of the elongate tissue anchor in one of the retracted position and the deployed position.

CROSS-REFERENCE TO RELATED APPLICATIONS

MICROFICHE APPENDIX

GOVERNMENT RIGHTS IN PATENT

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical device, and, more particularly, to an introducer cannula having a tissue anchor, the introducer cannula being configured for use with a medical instrument.

2. Description of the Related Art

A biopsy may be performed on a patient to help in determining whether the cells in a tissue lesion to be biopsied are cancerous. A typical biopsy apparatus includes a hand-held driver assembly having one or more drivers that drivably engage driven components of a disposable biopsy probe mechanism configured for releasable attachment to the driver assembly. The biopsy probe mechanism typically includes a biopsy cannula, e.g., a needle, having a sample port for receiving the tissue to be sampled, and a cutting cannula for severing tissue received in the sample port.

For surgical biopsies, the physician may introduce a localization (“loc”) wire under image guidance, which anchors to the target lesion and provides a physical pathway to the biopsy site for subsequent surgery. The loc wire features hooks and/or other geometries to anchor to the tissue.

In some circumstances, an introducer cannula may be used to aid in maintaining an access pathway to the tissue lesion. The pathway may be used to for obtaining tissue samples via the biopsy apparatus and for subsequently introducing a tissue marker. However, problems may be experienced if the introducer cannula used to maintain the access pathway to the tissue lesion undergoes migration, which as a result would require the physician to reposition the introducer cannula to avoid the biopsy being performed at the wrong location or a tissue marker being deployed at the wrong location.

SUMMARY OF THE INVENTION

The present invention provides tissue anchoring features on an introducer cannula to aid in preventing migration of the introducer cannula for accurate positioning of a medical instrument, such as a biopsy probe of a biopsy apparatus or a marker cannula of a tissue marking apparatus.

The invention, in one form thereof, is directed to an introducer cannula configured for receiving a medical instrument. The introducer cannula includes a cannula tube having a side wall, a proximal end, and a distal end, and the side wall surrounding a central lumen. The cannula tube has a central longitudinal axis passing through the central lumen and extends between the proximal end and the distal end. An elongate tissue anchor is positioned in the central lumen of the cannula tube. The elongate tissue anchor has a mounting end and an anchoring free end. The elongate tissue anchor is movable in the central lumen such that the anchoring free end is movable between a retracted position and a deployed position. An actuator is coupled to the proximal end of the cannula tube. The actuator is coupled to the mounting end of the elongate tissue anchor. The actuator is operatively configured to selectively position the anchoring free end of the elongate tissue anchor in one of the retracted position and the deployed position.

The invention, in another form thereof, is directed to a biopsy system. The biopsy system includes a medical instrument and an introducer cannula configured for receiving the medical instrument. The introducer cannula includes a cannula tube having a side wall, a proximal end, and a distal end, and the side wall surrounding a central lumen. An elongate tissue anchor is positioned in the central lumen of the cannula tube. The central lumen is sized to concurrently accommodate both the elongate tissue anchor and a portion of the medical instrument. The elongate tissue anchor has a mounting end and an anchoring free end. The elongate tissue anchor is movable in the central lumen such that the anchoring free end is movable between a retracted position and a deployed position. An actuator is coupled to the proximal end of the cannula tube. The actuator is coupled to the mounting end of the elongate tissue anchor. The actuator is operatively configured to selectively position the anchoring free end of the elongate tissue anchor in one of the retracted position and the deployed position.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly toFIG. 1, there is shown an exemplary biopsy system kit10, which may include, for example, a biopsy apparatus12, a marking apparatus14, an introducer cannula16and a stylet18. Biopsy apparatus12is used to perform a biopsy procedure on a patient. Following a biopsy procedure, a physician may mark the biopsy site with a tissue marker, which may be deployed, for example, using marking apparatus14.

Introducer cannula16is provided to aid in the transition from the biopsy apparatus12to marking apparatus14, and to aid in the positioning of either of biopsy apparatus12or marking apparatus14. As will be described in more detail below, introducer cannula16may be inserted into the patient during insertion of the probe portion of biopsy apparatus12into the patient, or alternatively, may be inserted into the patient with the aid of the removable stylet18. In any event, introducer cannula16may be used to maintain an access pathway to the tissue lesion and/or biopsy site in the patient.

Referring toFIG. 2, biopsy apparatus12includes a driver assembly20and a biopsy probe mechanism22. Driver assembly20is configured to provide operative control over biopsy probe mechanism22. Driver assembly20includes a housing24configured, e.g., ergonomically designed, to be grasped by a user, e.g., a physician. Housing24defines a compartment26into which biopsy probe mechanism22is at least partially positioned when biopsy probe mechanism22is attached to driver assembly20, with biopsy probe mechanism22being drivably coupled to driver assembly20.

Driver assembly20further includes a user interface28located to be externally accessible to the user with respect to housing24for receiving operation commands from the user, e.g., through one or more pushbuttons, and may also include a display, e.g., one or more lights or an LCD (liquid crystal display), to display information to the user. A controller30is communicatively coupled user interface28via a communication link32, such as for example, wire cabling, printed circuits, etc. Controller30may include, for example, a microprocessor and associated memory (not shown) for executing program instructions to perform functions associated with the harvesting of biopsy tissue samples during a biopsy procedure.

There is contained within housing24an electromechanical drive34and a pressure source36. Electromechanical drive34is connected in electrical communication with controller30via a communication link38, such as for example, wire cabling, printed circuits, etc. Electromechanical drive34is further drivably coupled (illustrated by dashed lines) to the biopsy probe mechanism22and to the pressure source36to selectively and operatively control biopsy probe mechanism22and pressure source36. Electromechanical drive34may include, for example, one or more of a linear drive that converts rotational motion to linear motion (e.g., a worm gear arrangement, rack and pinion arrangement, solenoid-slide arrangement, etc.) and a rotational drive that may include one or more of a gear, gear train, belt/pulley arrangement, etc., for effecting operation of biopsy probe mechanism22and/or pressure source36.

Pressure source36may be, for example, a peristaltic pump, a diaphragm pump, syringe-type pump, etc. Pressure source36may be permanently integrated into driver assembly20, or alternatively may be permanently integrated as a part of the biopsy probe mechanism22. In either case, pressure source36is coupled in fluid communication with biopsy probe mechanism22, e.g., via conduit40, and is configured to generate negative pressure (vacuum), and in some embodiments may also generate positive pressure.

Biopsy probe mechanism22is generally intended to be disposable as a unit and intended for use on a single patient. Biopsy probe mechanism22includes a frame42to which is attached a biopsy probe44. Biopsy probe44includes a sample receiving member46and a cutting cannula48. Sample receiving member46and a cutting cannula48are arranged coaxially with respect to a longitudinal axis50. Cutting cannula48has a distal cutting edge52. Sample receiving member46and a cutting cannula48are mounted as a coaxial unit to frame42.

In the present embodiment, sample receiving member46may be formed, for example, as an elongate cylindrical tube54having a proximal end56and a distal end58. Sample receiving member46may be made, for example, from a metal, such as stainless steel, titanium, or a nickel alloy. In the present embodiment, distal end58has a piercing tip60. Longitudinal axis50extends between proximal end56and distal end58.

A sample receiving notch62is formed in sample receiving member46, e.g., by machining a portion of a sample receiving notch62of sample receiving member46and extends into a lumen64of sample receiving member46(shown by dashed lines). Sample receiving notch62is configured to receive the tissue to be biopsied, and to retain the tissue sample harvested from the tissue, during a biopsy procedure. Sample receiving notch62may be also sometimes referred to as a sample chamber. Sample receiving notch62in sample receiving member46is coupled in fluid communication with pressure source36via conduit40. It is to be understood, however, that some designs of biopsy apparatus12may not utilize a pressure source.

In preparation for insertion of biopsy probe44of biopsy probe mechanism22into introducer cannula16, for example, cutting cannula48is controlled by controller30and electromechanical drive34to translate linearly along longitudinal axis50to cover sample receiving notch62(shown in phantom lines inFIG. 2) of sample receiving member46. In operation, a user may use piercing tip60of biopsy probe44to establish an access pathway through tissue to a biopsy site, with biopsy probe44having been inserted through introducer cannula16.

After insertion of biopsy probe44into the patient at the desired location, cutting cannula48is controlled by controller30and electromechanical drive34to translate linearly along longitudinal axis50to expose sample receiving notch62(shown in solid lines inFIG. 2) to receive a tissue sample, and thereafter is controlled to cause cutting cannula48to translate linearly along longitudinal axis50during a linear advancement to cover sample receiving notch62(shown in phantom lines inFIG. 2) and sever the tissue in sample receiving notch62. Also, cutting cannula48may be controlled to rotate or oscillate with, or independent from, any linear advancement of cutting cannula48.

Thereafter, biopsy probe44may be withdrawn from introducer cannula16, and in turn withdrawn from the patient, while introducer cannula16remains in the tissue of the patient to maintain the access pathway and to maintain the location of the biopsy site.

Referring toFIG. 3, marking apparatus14includes a handle66, a marker cannula68, a marker introducer rod70, and a deployment mechanism72. Handle66is configured to be grasped by a user, i.e., is of an appropriate size and shape to be grasped by the hand of the user of marking apparatus14. Deployment mechanism72is operatively coupled to marker introducer rod70. Marker cannula68is configured for holding at least one tissue marker74for deployment into a tissue mass of a patient, and may be in the form of a hollow tube having a side port76(or alternatively an end port) leading into a lumen78in which tissue marker74is located. Also positioned for linear travel in lumen78is marker introducer rod70.

In operation, a user positions marking apparatus14by inserting marker cannula68into a prepositioned introducer cannula16. Once the marking apparatus is in the proper position, a user then depresses deployment mechanism72, which in turn advances marker introducer rod70to deploy tissue marker74out of side port76.

Referring again toFIGS. 1 and 2, as an alternative to using the piercing tip60of biopsy probe44to establish the access pathway through tissue of the patient, stylet18may be used for this purpose. Stylet18includes a handle80fixedly attached to a shaft82, with shaft82having a piercing tip84at an end opposite to handle80. In operation, a user may use piercing tip84of shaft82to establish a pathway through tissue to a biopsy site, with shaft82of stylet18having been inserted through introducer cannula16. Thus, stylet18may be used to position introducer cannula16in tissue of a patient, independent of biopsy apparatus12and/or marking apparatus14.

Referring toFIGS. 4A-4Ethere is shown an embodiment of introducer cannula16, hereinafter referred to as introducer cannula16-1. Introducer cannula16-1includes a cannula tube90, an elongate tissue anchor92, and an actuator94.

Cannula tube90has a side wall96surrounding a central lumen98, a proximal end100, and a distal end102. Cannula tube90has a central longitudinal axis104passing through central lumen98that extends between proximal end100and distal end102. As illustrated inFIGS. 4C-4E, a cross section of central lumen98is sized to concurrently accommodate both elongate tissue anchor92and one of biopsy probe44of biopsy apparatus12, marker cannula68of marking apparatus14, and shaft82of stylet18. Cannula tube90is substantially rigid, and may be made, for example, from a metallic material, such as for example, stainless steel, nitinol, a nickel-chromium alloy, titanium, etc. As used immediately above, the term “substantially rigid” refers to structure that exhibits little, if any, radial deflection relative to central longitudinal axis104in normal use.

Referring again toFIGS. 4A-4C, elongate tissue anchor92is positioned in central lumen98of cannula tube90. Elongate tissue anchor92has a mounting end106and an anchoring free end108. Anchoring free end108of elongate tissue anchor92may include a pair of barbs108-1spaced apart along a longitudinal extent of elongate tissue anchor92, or some other anchoring configuration, such as a hook. Elongate tissue anchor92may be configured to be flexible, while exhibiting little or no permanent deformation during normal use. Elongate tissue anchor92may be formed, for example, as a wire or rod made of metallic material, such as for example, stainless steel, a nickel-chromium alloy, titanium, etc, and in some embodiments may be formed from a “memory” material, such as nitinol.

Anchoring free end108of elongate tissue anchor92is movable in central lumen98between a retracted position110and a deployed position112. When anchoring free end108of elongate tissue anchor92is in retracted position110, for example, anchoring free end108is completely contained within central lumen98proximal to distal end102of cannula tube90. When anchoring free end108of elongate tissue anchor92is in deployed position112, anchoring free end108is completely exposed external to central lumen98distal to distal end102of cannula tube90.

Actuator94is coupled to proximal end100of cannula tube90. Actuator94is also coupled to mounting end106of elongate tissue anchor92. Actuator94is operatively configured to selectively position anchoring free end108of elongate tissue anchor92in one of the retracted position110and the deployed position112.

More particularly, in the present embodiment actuator94includes a hub114fixedly connected to proximal end100of cannula tube90. Hub114has a hollow interior116coaxial with central lumen98with respect to central longitudinal axis104. Hub114has a guide slot118having a proximal circumferential slotted portion118-1, a distal circumferential slotted portion118-2, and a longitudinal portion118-3extending between proximal circumferential slotted portion118-1and distal circumferential slotted portion118-2. Proximal circumferential slotted portion118-1defines the retracted position110and distal circumferential slotted portion118-2defines the deployed position112, with the longitudinal extent of longitudinal portion118-3defining the longitudinal distance traveled by anchoring free end108when moved from retracted position110to deployed position112.

An actuation lever120is mounted in guide slot118. Actuation lever120has a first end120-1and a second end120-2. The first end120-1is positioned to extend outwardly from guide slot118. The second end120-2is positioned in hollow interior116and is connected to the mounting end106of elongate tissue anchor92. Accordingly, movement of actuation lever120along guide slot118results in a corresponding movement of elongate tissue anchor92. Elongate tissue anchor92extends from mounting end106connected to actuation lever for substantially a full longitudinal extent of cannula tube90to anchoring free end108. As used immediately above, the term “substantially” refers to a range of 90 percent to 100 percent of the extent of cannula tube90.

Referring toFIGS. 4D and 4E, introducer cannula16-1is configured to removably receive a portion of a medical instrument, such as biopsy probe44of biopsy apparatus12, marker cannula68of marking apparatus14, or shaft82of stylet18. More particularly, for example, cannula tube90is configured in cross sectional size and shape to removably receive the portion of the medical instrument in central lumen98in cannula tube90concurrently with, and immediately adjacent to, elongate tissue anchor92in central lumen98.

To establish a pathway in tissue of a patient, for example, one of the piercing tip60of biopsy probe44or piercing tip84of stylet18may be used. In the first instance, biopsy probe44is inserted though central lumen98of cannula tube90, with piercing tip60extending beyond distal end102of cannula tube90. In the instance of stylet18, shaft82of stylet18is inserted though central lumen98of cannula tube90, with piercing tip84extending beyond distal end102of cannula tube90. Thus, either of biopsy probe44of biopsy apparatus12or stylet18may be used to establish an access pathway and position introducer cannula16-1in tissue of a patient.

Thereafter, actuator94of introducer cannula16-1is actuated to deploy anchoring free end108of elongate tissue anchor92to the deployed position112at which time anchoring free end108of elongate tissue anchor92engages the tissue of the patient to anchor introducer cannula16-1to the tissue of the patient and maintain the access pathway in the tissue of the patient established by the piercing tip (e.g., one of piercing tip60of biopsy probe44or piercing tip84of stylet18). Once anchored, introducer cannula16-2permits a respective medical instrument, e.g., biopsy apparatus12, to be removed from the anchored introducer cannula16-1and reinserted in the patient while maintaining the established access pathway. Additionally, the anchored introducer cannula16-2permits a respective medical instrument, e.g., biopsy apparatus12, to be removed from the anchored introducer cannula16-1and replaced with a medical instrument of a different type, e.g., marking apparatus14, for performing a different procedure using the same access pathway in the tissue maintained by the anchored introducer cannula16-1.

After all medical procedures involving introducer cannula16-1have been completed, then introducer cannula16-1may be removed from the patient by first retracting elongate tissue anchor92to the retracted position110, and then removing cannula tube90from the tissue of the patient.

Referring toFIGS. 5A-Ethere is shown another embodiment of introducer cannula16, hereinafter referred to as introducer cannula16-2. Introducer cannula16-2includes a cannula tube130, an elongate tissue anchor132, and an actuator134.

Cannula tube130has a side wall136surrounding a central lumen138, a proximal end140, and a distal end142. Cannula tube130has a central longitudinal axis144passing through central lumen138that extends between proximal end140and distal end142. As illustrated inFIG. 5Ewith reference toFIG. 5D, a cross section of central lumen138is sized to concurrently accommodate both elongate tissue anchor132and one of biopsy probe44of biopsy apparatus12, marker cannula68of marking apparatus14, and shaft82of stylet18. Cannula tube130is substantially rigid, and may be made, for example, from a metallic material, such as for example, stainless steel, nitinol, a nickel-chromium alloy, titanium, etc. As used immediately above, the term “substantially rigid” refers to structure that exhibits little, if any, radial deflection relative to central longitudinal axis144in normal use.

Elongate tissue anchor132is positioned in central lumen138of cannula tube130. In the present embodiment, elongate tissue anchor132is formed as a plurality of individual elongate anchor elements which number as two in the exemplary embodiment shown inFIGS. 5A-5E, and which are individually identified as elongate anchor element146and elongate anchor element148. Each of elongate anchor elements146,148is configured to be flexible, while exhibiting little or no permanent deformation during normal use. Each of elongate anchor elements146,148has an actual length that is longer than the longitudinal extent in the direction of longitudinal axis144of cannula tube130. Each of elongate anchor elements146,148is formed in a spiral and is positioned in central lumen138to frictionally engage the side wall136of cannula tube130. Elongate tissue anchor92may be formed, for example, as a wire made of metallic material, such as for example, stainless steel, a nickel-chromium alloy, titanium, etc, and in some embodiments may be formed from a “memory” material, such as nitinol.

Elongate anchor element146has a mounting end150and an anchoring free end152. Elongate anchor element148has a mounting end154and an anchoring free end156. The mounting end150of elongate anchor element146and the mounting end154of elongate anchor element148are respectively connected to actuator134in an opposing relationship. Anchoring free end152of elongate anchor element146may be in the form of a sharpened hooked end152-1, or alternatively some other anchoring structure, such as a barb. Anchoring free end156of elongate anchor element148may be in the form of a sharpened hooked end156-1, or alternatively some other anchoring structure, such as a barb.

Actuator134includes a hub158rotatably coupled to proximal end140of cannula tube130. Hub158includes an annular channel160in which an annular flange130-1of cannula tube130is rotatably engaged. Hub158has a hollow interior162coaxial with central lumen138. The respective mounting ends150,154of each of elongate anchor elements146,148of elongate tissue anchor132are connected to hub158in an opposing relationship, e.g., at opposite sides of hub158, in hollow interior162. Each of elongate anchor elements146,148of elongate tissue anchor132form a spiral (i.e., coil-like) shape within central lumen138of cannula tube130with each of elongate anchor elements146,148of elongate tissue anchor132being in frictional engagement with side wall136of cannula tube130.

In operation, a rotation of hub158in a first rotational direction164moves the respective anchoring free ends152,156of each of elongate anchor elements146,148of elongate tissue anchor132toward a retracted position166, and a rotation of hub158in a second rotational direction168opposite first rotational direction164moves anchoring free ends152,156of each of elongate anchor elements146,148of elongate tissue anchor132toward a deployed position170. In other words, a rotation of hub158in the first rotational direction164moves the respective anchoring free ends152,156of each of elongate anchor elements146,148of elongate tissue anchor132toward the retracted position166by winding each of elongate anchor elements146,148of elongate tissue anchor132within central lumen138of cannula tube130to decrease the effective length of each of elongate anchor elements146,148of elongate tissue anchor132relative to longitudinal extent of cannula tube130. Conversely, and a rotation of hub158in the second rotational direction168opposite first rotational direction164moves anchoring free ends152,156of each of elongate anchor elements146,148of elongate tissue anchor132toward a deployed position170by unwinding each of elongate anchor elements146,148of elongate tissue anchor132within central lumen138of cannula tube130to increase the effective length of each of elongate anchor elements146,148of elongate tissue anchor132relative to longitudinal extent of cannula tube130.

Referring toFIGS. 5D and 5E, introducer cannula16-2is configured to removably receive a portion of a medical instrument, such as biopsy probe44of biopsy apparatus12, marker cannula68of marking apparatus14, or shaft82of stylet18. More particularly, for example, cannula tube130is configured in cross sectional size and shape to removably receive the portion of the medical instrument, e.g., biopsy probe44, in central lumen138in cannula tube130concurrently with, and immediately adjacent to, elongate tissue anchor132(e.g., elongate anchor elements146,148) in central lumen98.

To establish a pathway in tissue of a patient, for example, one of the piercing tip60of biopsy probe44or piercing tip84of stylet18may be used. In the first instance, biopsy probe44is inserted though central lumen138of cannula tube130, with piercing tip60extending beyond distal end142of cannula tube130. In the instance of stylet18, shaft82of stylet18is inserted though central lumen138of cannula tube130, with piercing tip84extending beyond distal end142of cannula tube90. Thus, either of biopsy probe44of biopsy apparatus12or stylet18may be used to establish an access pathway and position introducer cannula16-2in tissue of a patient.

Thereafter, actuator134of introducer cannula16-2is actuated to deploy anchoring free ends152,156of elongate anchor elements146,148forming elongate tissue anchor132to the deployed position170at which time anchoring free ends152,156of elongate anchor elements146,148forming elongate tissue anchor132engage the tissue of the patient to anchor introducer cannula16-2to the tissue of the patient and maintain the access pathway in the tissue of the patient established by the piercing tip (e.g., one of piercing tip60of biopsy probe44or piercing tip84of stylet18).

Once anchored, introducer cannula16-2permits a respective medical instrument, e.g., biopsy apparatus12, to be removed from the anchored introducer cannula16-2and reinserted in the patient while maintaining the established pathway. Additionally, the anchored introducer cannula16-2permits a respective medical instrument, e.g., biopsy apparatus12, to be removed from the anchored introducer cannula16-2and replaced with a medical instrument of a different type, e.g., marking apparatus14, for performing a different procedure using the same access pathway in the tissue maintained by the anchored introducer cannula16-2.

After all medical procedures involving introducer cannula16-2have been completed, then introducer cannula16-2may be removed from the patient by first retracting anchoring free ends152,156of elongate anchor elements146,148forming elongate tissue anchor132to the retracted position166, and then removing cannula tube130from the tissue of the patient.

Thus, in summary, in accordance with an aspect of the present invention, the introducer cannula16(e.g.,16-1,16-2) includes a retractable/deployable elongate tissue anchor to aid in preventing migration of the introducer cannula16in a patient. The anchored introducer cannula16facilitates the accurate positioning in the patient of one or more medical instruments, such as a biopsy probe44of a biopsy apparatus12or a marker cannula68of tissue marking apparatus14. Advantageously, the introducer cannula16may be anchored to the tissue of a patient to maintain an access pathway in the tissue, while the respective medical instrument may be removed from and re-installed in the same access pathway in the tissue via the anchored introducer cannula16. Similarly, a respective medical instrument may be removed from the anchored introducer cannula16and replaced with a medical instrument of a different type for performing a different procedure using the same access pathway in the tissue maintained by the anchored introducer cannula16. After all medical procedures have been completed, introducer cannula16then may be removed from the patient by retracting the elongate tissue anchor and sliding the introducer cannula out of the access pathway in the patient.