Patent Description:
A hollow needle may be used in an EUS-guided procedure to access target anatomy, e.g. an intestinal lumen, and introduce a guidewire through the needle lumen into the target anatomy to, e.g., guide a stenting procedure. The guidewire, when it is extended distally from the needle tip, may be bent in multiple directions and at different points such that, when the physician attempts to retract the guidewire into the needle, the guidewire may catch on the sharp edge or tip of the needle, potentially stripping the guidewire. The stripped material may be left behind in the anatomy and/or may expose the metal wire core of the guidewire and create an electrical safety hazard. <CIT> discloses an introducer needle comprising a cannula defining a bore within the cannula and having a beveled end defining a distal opening of the bore of the cannula. At least one protrusion is arranged on a proximal surface of the beveled end proximate the distal opening. <CIT> discloses a needle adapted for a mechanically assisted insertion of the needle into an object, wherein the needle comprises a cylindrical body enclosing a channel and a cutting part at the exit of the channel and the cutting part comprises one planar bevel and at least one surface irregularity causing a peak of the insertion resistance force of the needle into the object. <CIT> discloses a hair implantation needle comprising an elongated body having a lumen sized to receive a follicular unit and a distal end with a distal tip configured to penetrate a body surface; wherein the distal end comprises a beveled portion and a relief portion with a narrow cut-out in a wall of the elongated body, wherein the beveled portion and the relief portion are configured and sized relative to each other to prevent coring and provide a non-coring needle. <CIT> discloses a method of accessing a body lumen, the method comprises advancing an access system adjacent to the body lumen, wherein the access system comprises an access catheter and a stylet with a piercing tip. <CIT> discloses a body access device comprising a slotted needle having a sharpened distal tip and being configured to receive a further element introduced into the needle through the slot. <CIT> discloses a ratcheted handle for a fiducial deployment system comprising a fiducial needle configured to retain and to distally deploy a plurality of fiducials and an advancement mechanism for said fiducial deployment. <CIT> discloses an injection system for delivering a fluid medium. The injection system comprises a needle cannula, an injection tubing, a sliding member affixed to the injection tube such that a sliding movement of the injection tubing limits a stroke of the injection tubing to a fixed distance, and a connector for coupling the injection tube to a fluid source. <CIT> discloses a hollow non-coring needle having a lumen and having a beveled front face providing a lumen opening, the face also providing a heel surface behind said lumen opening. A rear edge portion of the lumen opening adjacent the heel provides a smooth, rounded and dull surface.

No surgical methods form part of the invention.

The present disclosure relates to an access needle which includes a hollow shaft having a lumen sized and shaped to slidably receive a guidewire therein and having a distal end including an angled surface extending proximally and transversely from a sharpened distal-most tip of the shaft to a beveled smoothed area of the shaft proximal and transverse to the sharpened tip, the beveled smoothed area being positioned to slidably engage a guidewire extended distally out the distal end of the needle so that, as the guidewire is retracted proximally into the needle, the beveled smoothed area slidably engages the guidewire to minimize abrasion to the guidewire.

In an embodiment, the distal end of the shaft includes sharp cutting surfaces extending proximally from the sharpened tip, the beveled smoothed area being positioned so that, as a guidewire extending out of the distal end of the needle along a curve is retracted into the needle in a desired orientation relative to the needle, a surface of the guidewire which forms a radially inner surface along the curve contacts the beveled smoothed area of the needle.

In an embodiment, wherein the distal end of the shaft includes a first sharp cutting surface extending from the distal-most tip to a first transition and a second sharp cutting surface extending from the first transition to a second transition, the first sharp cutting surface extending at a first angle relative to a longitudinal plane of the shaft at the distal-most tip and curving to a second angle relative to the longitudinal plane of the shaft at the first transition, the second cutting surface having a third angle relative to the longitudinal plane of the shaft.

In an embodiment, the distal end of the shaft includes a third sharp cutting surface extending from the distal-most tip to a third transition and a fourth sharp cutting surface extending from the third transition to a fourth transition, the third sharp cutting surface extending at a fourth angle relative to a longitudinal plane of the shaft at the distal-most tip and curving to a fifth angle relative to the longitudinal plane of the shaft at the third transition, the fourth sharp cutting surface extending at a sixth angle relative to the longitudinal plane of the shaft.

In an embodiment, the first and second sharp cutting surfaces are substantially symmetric relative to a midplane of the needle with respect to the third and fourth sharp cutting surfaces.

In an embodiment, the first angle is in a first range of <NUM>-<NUM> degrees, the second angle is in a second range of <NUM>-<NUM> degrees and the third angle is in a third range of <NUM>-<NUM> degrees.

In an embodiment, the beveled smoothed area is defined by a U-shaped surface having a midpoint proximal and transverse to the sharpened tip, the U-shaped surface having a curvature at the midpoint parallel to a transverse plane of the shaft.

In an embodiment, the beveled smoothed area includes an outer bevel on an outer surface of the shaft and an inner bevel on an inner surface of the shaft.

In an embodiment, the shaft includes a feature extending along a distal portion thereof configured to mechanically engage a corresponding feature of a guidewire inserted therein to maintain the guidewire in a desired rotational orientation relative to the needle.

In an embodiment, the feature of the shaft includes a slot extending along a portion of a length of the needle configured to receive a tab extending radially from the guidewire.

The present disclosure also relates to an access needle assembly which includes an anchoring guidewire including a first orienting feature; and an access needle including a hollow shaft having a lumen sized and shaped to slidably receive the guidewire therein and having a distal end including a cut surface extending proximally and transversely from a sharpened distal-most tip of the shaft to a beveled smoothed area of the shaft proximal and transverse to the sharpened tip, the beveled smoothed area being positioned to slidably engage the guidewire extended distally out the distal end of the needle so that, as the guidewire is retracted proximally into the needle, the beveled smoothed area slidably engages the guidewire to minimize abrasion to the guidewire, the access needle further including a second orienting feature extending along a distal portion thereof configured to mechanically engage the first orienting feature to maintain the guidewire in a desired rotational orientation relative to the access needle.

In an embodiment, the second orienting feature includes a slot extending along a portion of a length of the needle and the first orienting feature includes a tab projecting outward from the guidewire.

In an embodiment, the tab has a ramped section to facilitate engagement of the shaft and the tab so that, when the needle is retracted proximally over the guidewire, the ramp engages a distal end of the slot so that the tab is folded over and passes through the needle until the tab has emerged from the distal end of the needle.

In an embodiment, the second orienting feature includes a slot extending along a portion of a length of the needle and the first orienting feature includes a tab projecting outward from the guidewire, the tab being configured to be severed from the guidewire as the needle is withdrawn proximally over the guidewire.

In an embodiment, the guidewire has a nitinol core with a polymer coating.

The present disclosure further relates to a method which includes extending a guidewire distally out of a distal end of an access needle, the access needle including a hollow shaft having a lumen sized and shaped to slidably receive the guidewire therein, the distal end of the needle including a cut surface extending proximally and transversely from a sharpened distal-most tip of the shaft to a beveled smoothed area of the shaft proximal and transverse to the sharpened tip; retracting the guidewire proximally back into the needle so that the beveled smoothed area slidably engages the guidewire to minimize abrasion to the guidewire.

In an embodiment, the method further includes rotating the guidewire relative to a longitudinal axis of the access needle to position a curve of the guidewire so that a portion of the guidewire surface forming a radially inner part of the curve contacts the beveled smooth area as the guidewire is retracted into the needle.

In an embodiment, the guidewire is rotated under ultrasound guidance so that the curved distal end curves away from a side of the needle on which the distal tip of the needle is formed.

The present disclosure may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments describe devices having a needle with smoothed surfaces for ease of advancing or retracting a guidewire without damaging the guidewire. The exemplary devices may include means for aligning the guidewire within the needle so that the guidewire is caused to interact with the smoothly ground surfaces instead of sharper edges defined in the needle tip.

<FIG> shows a distal end of an access needle <NUM> having a distal end <NUM> with a sharp distal tip <NUM> for puncturing target anatomy and a plurality of machined surfaces shaped to facilitate smooth advancement and retraction of a guidewire <NUM> out of and back into the distal end <NUM>. The needle <NUM> is formed as a hollow shaft <NUM> sized and shaped to slidably receive a guidewire <NUM> so that it may pass therethrough to be extended distally from the distal tip <NUM> as would be understood by those skilled in the art. The needle <NUM> may be formed from any suitable material, such as a nitinol alloy, a cobalt-chromium alloy, stainless steel, etc. The guidewire <NUM> may be configured to bend multiple times over a tortuous path which an insertion device such as an endoscope has traversed via, for example, a natural body lumen to access a target tissue structure. Additionally, the guidewire may be an anchoring guidewire having a shaped distal end that enables anchoring of tissue.

In the present embodiment, as shown in <FIG>, the guidewire <NUM>, in its unconstrained state, has a curved end <NUM> pre-formed to assume a curved shape having two curved sections <NUM>, each curving through an angle of up to approximately ~<NUM> degrees in the same curvature direction such that, when unconstrained, a distal tip <NUM> of the guidewire <NUM> points in a direction angled up to approximately ~<NUM> degrees relative to the longitudinal axis of a portion of the guidewire <NUM> proximal to the curved end <NUM>. However, guidewires having other curvatures may be used. As would be understood by those skilled in the art, the guidewire <NUM> is sufficiently flexible so that the curved end <NUM> can conform to the path along which the interior of the hollow shaft <NUM> extends when one or both of the curved sections <NUM> are withdrawn into the shaft <NUM>. The guidewire <NUM> may have, for example, a nitinol core covered in a polymer coating.

When the curved end <NUM> of the wire <NUM> is extended distally out the distal tip <NUM> of the needle <NUM>, i.e., when the curved end <NUM> is not constrained by the inner diameter of the shaft <NUM>, the distal tip <NUM> of the guidewire <NUM> reverts to its unconstrained state. However, the guidewire <NUM> as described herein is used for exemplary purposes only, and any guidewire may be used with the access needle <NUM>. For example, the guidewire may be curved at different points in different curvature directions and/or have more or fewer curves. Those skilled in the art will understand that guidewires with significant curvature at their distal ends are the most likely to be damaged upon withdrawal into a conventional needle as a radially inner side of the curved end is dragged over the sharp end of the needle to re-enter the lumen of the needle. As would be understood by those skilled in the art, guidewires with pre-formed curved distal ends are often used as anchoring guidewires. That is, this type of guidewire may be inserted into a target structure via a needle or other insertion device that holds the curved distal end substantially straight. Furthermore, the guidewire may be of any desired construction.

When the target structure has been accessed, the guidewire <NUM> may be advanced distally out of the needle <NUM> (or the needle <NUM> may be withdrawn proximally over the guidewire <NUM>) to free the curved end <NUM> to assume its curved configuration. In this curved state, the guidewire <NUM> is no longer able to pass proximally out of the aperture through which it entered the target tissue structure and so is anchored within the target structure. The needle <NUM> may then be withdrawn proximally over the guidewire <NUM> which may then be used to provide a pathway for the insertion of other treatment devices (e.g., stents, etc.) over the guidewire <NUM> into the target structure.

When the procedure is completed, the needle <NUM> is again advanced distally over the guidewire <NUM> into the target structure. At this point, the guidewire <NUM> is withdrawn proximally into the needle <NUM> during which operation, contact between the walls of the lumen of the needle <NUM> and the guidewire <NUM> constrain the guidewire to return to the path of the lumen of the needle <NUM>. The needle <NUM> with the guidewire received therein may then be withdrawn from the body. The needles of the present embodiments are directed to minimizing or eliminating damage to guidewires during their withdrawal proximally into the lumen of the needle.

The opening at the distal end <NUM> of the needle <NUM> is defined by a plurality of machined surfaces cut into the hollow shaft <NUM>. The opening is defined by a first segment <NUM>, a second segment <NUM> and a third segment <NUM>. The segments are defined in the manner described below, relative to a needle coordinate system with a longitudinal axis A, a first transverse axis B and a second transverse axis C, the axes defining a first longitudinal plane AC, a second longitudinal plane BC and a transverse plane AB, as shown in <FIG>.

The distal end <NUM> has a sharp, tissue-penetrating, distal tip <NUM> at the origin of the needle coordinate system, i.e. the distal-most point of the access needle <NUM>. In this embodiment, the opening at the distal end <NUM> of the needle <NUM> is substantially symmetrical with respect to the distal tip <NUM> so that the first, second and third segments on either side of the AC plane are mirror images of one another. The first segment <NUM> is defined by a first cut extending proximally and transversely from the distal tip <NUM> into the cylindrical wall of the needle <NUM>.

The first cut begins at the distal tip <NUM> at a first angle relative to the BC plane, the first angle being between approximately <NUM> degrees and <NUM> degrees, i.e., substantially parallel or nearly parallel to the BC plane, and gradually steepens to a second angle relative to the BC plane at a first transition <NUM>, as may be seen in <FIG> and more clearly in <FIG>. For example, the second angle, i.e. the angle of the cut of the first segment <NUM> relative to the BC plane at the first transition <NUM>, may be between approximately <NUM> degrees and <NUM> degrees. Thus, the first cut results in a curved first segment <NUM> that progresses from a shallow distal-most angle nearly parallel to a longitudinal axis of the needle <NUM> to a deeper angle relative to the longitudinal axis at the first transition <NUM>. As noted above, the first cut of this embodiment is substantially symmetrical on both sides of the distal tip <NUM>.

The second segment <NUM> is defined by a second cut extending proximally and transversely from the first transition <NUM> to a second transition <NUM> and a third cut extending only proximally, i.e., substantially parallel to the BC plane, from the second transition <NUM> to a third transition <NUM>. The second cut is at a third angle relative to the BC plane, the third angle remaining substantially constant from the first transition <NUM> to the second transition <NUM>. For example, the third angle, i.e. the angle of the second cut relative to the BC plane, may be between approximately <NUM> degrees and <NUM> degrees. It is noted that the second and third cuts are reflected on both sides of the needle <NUM>. The cross section of the needle <NUM> at the first transition <NUM> is shown in <FIG>, and the cross section of the needle <NUM> at the second transition <NUM> is shown in <FIG>, which is the same as the cross section of the needle <NUM> at the third transition <NUM>.

As those skilled in the art would understand, the first, second and third angles may differ from the exemplary angles provided above without departing from the scope of the invention. The shape of the first and second segments <NUM>, <NUM> is configured for the puncturing and/or acquisition of tissue from a target site in a living body. Thus, the edges of the needle <NUM> resulting from the first, second and third cuts are left sharp.

The third segment <NUM> is defined by a fourth cut extending proximally and transversely from the third transition <NUM>. The fourth cut is parallel to the A axis throughout the cut, with a varying angle relative to the AC plane, forming a substantially U-shaped cavity in the third segment <NUM>. The fourth cut begins at the third transition <NUM> at a fourth angle relative to the AC plane, which may begin at approximately ~<NUM> degrees, with the angle gradually increasing to ~<NUM> degrees until the fourth cut reaches a midpoint <NUM>, i.e. the furthest proximal point in the cut distal end <NUM>. The angle of the fourth cut at the midpoint is substantially parallel to the AB plane and orthogonal to the AC plane. It is noted that the fourth cut is substantially symmetrical with respect to the AC plane. The fourth cut, in the absence of any further machining, would result in sharp edges on the inner and outer surfaces of the shaft <NUM>.

During an endoscopic procedure, such as a procedure to insert a stent or a rendezvous procedure, a guidewire such as the guidewire <NUM> shown in <FIG> may be introduced into a target anatomical space and advanced distally out of the needle <NUM>. This allows the guidewire <NUM> to revert to its unconstrained bent configuration anchoring it in the target space. After the procedure has been completed and it is desired to withdraw the guidewire <NUM> from the body, the user inserts the needle <NUM> over the guidewire <NUM> until the distal tip <NUM> of the needle <NUM> enters the target space. The user then withdraw the curved end <NUM> of the guidewire <NUM> proximally back into the distal end <NUM> of the needle <NUM>. As indicated above, if the guidewire <NUM> was drawn back into the needle <NUM> in such a manner that the guidewire <NUM> was dragged over a sharp tissue cutting surface the guidewire <NUM> may be damaged.

To mitigate the aforementioned risk, in an exemplary embodiment the needle <NUM> is machined further after the first, second, third and fourth cuts are made. As shown in <FIG>, the distal end <NUM> has an outer bevel <NUM>, smoothing the sharp edge on the outer surface of the third segment <NUM>, and an inner bevel <NUM>, smoothing the sharp edge on the inner surface of the third segment <NUM> to minimize the effects of contact between these surfaces and the guidewire <NUM>. A radius of curvature for both the outer bevel <NUM> and the inner bevel <NUM> may range from approximately <NUM>" to <NUM>". Furthermore, the outer bevel <NUM> and the inner bevel <NUM> each has a degree of curvature of approximately <NUM> degrees to avoid creating a new sharp edge. In another embodiment, the outer and inner bevel <NUM>, <NUM> may be an outer radius and inner radius, an outer chamfer and inner chamfer, or an outer fillet and an inner fillet. Moreover, the third segment <NUM> may have a combination of a bevel, radius, chamfer, and fillet (e.g. the sharp edge of the outer surface is a fillet and the sharp edge of the inner surface is a bevel).

<FIG> shows the needle <NUM> of <FIG> with the guidewire <NUM>, the curved end <NUM> of the guidewire <NUM>, extending distally out the distal end <NUM>. <FIG> show an exemplary interaction of the guidewire <NUM> with the distal end <NUM> during retraction thereof. The guidewire <NUM> in this embodiment is curved around the B axis of the needle, ensuring that, as the guidewire <NUM> is withdrawn into the needle <NUM>, it is drawn across the surface defined in the third segment <NUM> of the distal end <NUM> and not over the sharper surfaces of the first and second segments <NUM>, <NUM>, respectively. As may be seen in <FIG>, the guidewire <NUM> is drawn over the smoothed inner bevel <NUM>, thus mitigating the risk of the guidewire <NUM> being stripped during the retraction. As may be seen in <FIG>, when the radius of curvature of the guidewire <NUM> is small, the interaction between the guidewire <NUM> and the bevels <NUM>, <NUM> increases, such that the guidewire <NUM> may also be drawn over the outer bevel <NUM>.

To bring a guidewire into contact only with beveled third segment <NUM>, rather than the sharp first or second segments <NUM>, <NUM>, it must be ensured that the guidewire is properly aligned rotationally within the needle <NUM>. In other words, the curvature of the guidewire <NUM> during retraction must be oriented so that the curvature of the guidewire <NUM> extends generally within the AC plane and the guidewire <NUM> curves away from the side of the needle <NUM> on which the distal tip <NUM> is formed. If a guidewire has a more complex curvature (e.g., a curvature extending in more than one plane), the user may rotate the guidewire <NUM> or the needle <NUM> relative to the other under Ultrasonic visualization so that the segment that is currently entering the needle <NUM> is oriented in the AC plane as described above. Thus, the guidewire <NUM> will always contact the third segment <NUM> as it enters the needle <NUM>.

The needle <NUM> and the guidewire <NUM> may have features for enhancing their visualization under ultrasound guidance, such that the operating physician may ensure that the proper alignment of the needle <NUM> and guidewire <NUM> is achieved by monitoring the orientations of the elements. For example, the needle <NUM> and the guidewire <NUM> may be formed from echogenic materials. However, it is possible that retraction may occur without direct visualization. Thus, proper alignment of the elements may be ensured in an alternate manner.

<FIG> show an access needle <NUM> having a longitudinal slot <NUM> in its hollow shaft <NUM>. The access needle <NUM> may be used in conjunction with a guidewire <NUM> having a tab <NUM> projecting radially outward (e.g., welded or coated onto the wire <NUM>) that is sized and shaped to travel in the longitudinal slot <NUM> during distal advancement and proximal retraction of the guidewire <NUM> out of and into the needle <NUM>. The tab <NUM> is restricted from transverse motion by the slot <NUM>. In other words, interaction between the tab <NUM> and the slot <NUM> maintains the guidewire <NUM> in a selected rotational alignment relative to the access needle <NUM> throughout the procedure.

The slot <NUM>, in this embodiment, is closed at a distal end <NUM> of the needle <NUM>. However, in another embodiment, the slot <NUM> may be open at the distal end <NUM>. Thus, it may be ensured that the curvature of the guidewire <NUM> interacts only with the beveled portions of the needle <NUM>. Those skilled in the art will understand that this slot may be curved in a manner corresponding to the curvature of more complex guidewire shapes to ensure that a distal end of the guidewire <NUM> rotates into the desired alignment relative to the needle <NUM> at all times during the withdrawal of the guidewire <NUM> into the needle <NUM>.

In some procedures, the needle <NUM> is pulled proximally off the guidewire <NUM> after the guidewire <NUM> has been anchored in the target anatomy. The existence of the tab <NUM> could prevent such a withdrawal of the needle <NUM> if it is not designed to allow the needle <NUM> to pass thereover. As would be understood by those skilled in the art, the tab <NUM> may be designed so that it will snap off as the needle <NUM> is pulled proximally off the guidewire <NUM>. In another embodiment, the tab <NUM> may be designed to compress and pass through the distal end of the lumen of the needle <NUM> until it exits the distal end <NUM> of the needle <NUM>. The needle <NUM> may then be slid proximally off of the guidewire <NUM> and removed from the body. For example, the tab <NUM> may have a ramped section <NUM> that facilitates the folding over of a leading edge of the tab <NUM> as it reaches the distal end of the slot <NUM> so that the tab <NUM> folds over and is compressed into the lumen of the needle <NUM> as the tab <NUM> passes under the portion of the needle <NUM> distal to the distal end of the slot <NUM> as the needle <NUM> is drawn proximally over the guidewire <NUM>.

Claim 1:
An access needle (<NUM>), comprising:
a hollow shaft (<NUM>) having a lumen sized and shaped to slidably receive a guidewire (<NUM>) therein and having a distal end (<NUM>) including an angled surface extending proximally and transversely from a sharpened distal-most tip (<NUM>) of the shaft to a beveled smoothed area (<NUM>) of the shaft proximal and transverse to the sharpened tip (<NUM>), the beveled smoothed area (<NUM>) being positioned to slidably engage a guidewire (<NUM>) extended distally out the distal end (<NUM>) of the needle so that, as the guidewire (<NUM>) is retracted proximally into the needle (<NUM>), the beveled smoothed area (<NUM>) slidably engages the guidewire (<NUM>) to minimize abrasion to the guidewire (<NUM>);
wherein the distal end (<NUM>) of the shaft (<NUM>) includes a first sharp cutting surface extending from the distal-most tip (<NUM>) to a first transition (<NUM>) and a second sharp cutting surface extending from the first transition (<NUM>) to a second transition (<NUM>), the first sharp cutting surface extending at a first angle relative to a longitudinal plane (BC) of the shaft at the distal-most tip (<NUM>) and curving to a second angle relative to the longitudinal plane (BC) of the shaft at the first transition (<NUM>), the second cutting surface having a third angle relative to the longitudinal plane (BC) of the shaft.