Safety needle guard

A needle guard is disclosed. The needle guard includes a binding plate defining a multi-slot aperture adapted to receive a needle cannula therethrough. The needle guard also includes a biasing member for biasing the needle cannula within the multi-slot aperture, and a sensing arm connected to the binding plate. The sensing arm is adapted to contact a portion of the needle cannula, and is positionable for restricting movement of the needle cannula. The multi-slot aperture may include a first region having a first dimension, a second region having a second dimension, and optionally, a third region having a third dimension with the third dimension being smaller than the second dimension and the second dimension being smaller than the first dimension.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates generally to medical needles and, more particularly, to medical needles having a safety device for shielding the needle tip after withdrawal of the needle from a patient.

2. Description of Related Art

In order to adequately protect medical practitioners from inadvertent puncture and/or wounding from medical sharps, such as needles and syringes, safety shielding devices have been developed to limit the exposure from contaminated medical devices. In many procedures, the greatest avoidable risk of accidental needle puncture, also referred to as a “needlestick”, occurs during handling of the used needle, such as when a medical practitioner inserts the used needle into a protective sheath for disposal. This action usually requires the practitioner to move the hand which holds the sheath toward the needle tip. Any inaccuracy in this movement increases the probability of an accidental needlestick. This is particularly true for “long needles” commonly used in spinal and epidural procedures, in which the handle portion of the device is separated from the needle tip by a substantial distance.

Prior safety devices have been developed, which include a protective guard specifically dimensioned to surround and bind a predetermined needle size. The prior safety devices have been initially stored on the needle at a location remote from the patient tip. After use, the safety device is typically advanced over the patient tip to shield the medical practitioner. In view of the fact that prior safety devices have been dimensioned to accommodate a single gauge needle, a multitude of safety devices, corresponding to all utilized needle gauges, have been necessary. This contributes to increased manufacturing costs and stocking concerns.

In addition, in medical procedures utilizing long needles, it is common practice to first insert an introducer sheath into the patient, and subsequently introduce an inner cannula therethrough. Typically, both the inner cannula and the introducer sheath include a sharp pointed profile. Since the prior safety devices have been specifically designed to accommodate a single needle gauge, medical procedures utilizing an introducer sheath and an inner cannula have typically been performed without a safety device.

SUMMARY OF THE INVENTION

The present invention is directed to a single needle guard that is capable of shielding a plurality of needle gauges. In addition, the needle guard of the present invention is capable of transitioning from a first cannula dimension, such as corresponding to the dimension of an introducer sheath, to a second cannula dimension, such as corresponding to the dimension of an inner cannula.

In one embodiment, a needle guard includes a binding plate defining a multi-slot aperture adapted to receive a needle cannula therethrough. The needle guard also includes a biasing member biasing the needle cannula within the multi-slot aperture, and a sensing arm connected to the binding plate, adapted to contact a portion of the needle cannula, and positionable for restricting movement of the needle cannula.

The biasing member may be disposed adjacent the multi-slot aperture. The multi-slot aperture may include a first region having a first dimension, and a second region having a second dimension, with the second dimension being smaller than the first dimension. The biasing member may be initially positioned adjacent the first region of the multi-slot aperture. The biasing member may also be adapted to apply a biasing force adjacent the multi-slot aperture in a direction that is substantially perpendicular to a through-axis of the multi-slot aperture. The biasing member may be adapted to advance the needle cannula within the multi-slot aperture from the first region to the second region in a direction perpendicular to a longitudinal axis of the needle cannula. The sensing arm may further include a transverse barrier. The transverse barrier may include a base plate connected to the binding plate and extending in a distal direction from the binding plate. The transverse barrier may also include an engagement plate connected to, and extending from, the base plate in a direction toward a through-axis of the multi-slot aperture. The engagement plate may include a contact surface for contacting a portion of the needle cannula at a location distal from the multi-slot aperture. The contact surface may include an angled restraining lip extending toward the multi-slot aperture. The needle guard may also include a biasing element biasing the binding plate in a distal to proximal direction to bias the binding plate toward a tilted position. The needle guard may further include a second biasing element biasing the binding plate in a direction substantially aligned with the multi-slot aperture.

In another embodiment, a needle guard includes a housing, defining an interior, and having a first port and a second port extending therethrough and aligned along an axis of the housing. The needle guard also includes a locking mechanism disposed within the interior of the housing. The locking mechanism includes a binding plate defining a multi-slot aperture, with at least a portion of the multi-slot aperture aligned with the first port and the second port along the axis of the housing. The first port, the second port, and the multi-slot aperture are adapted to receive a needle cannula therethrough. The needle guard also includes a biasing member for biasing the needle cannula within the aperture. The needle guard also includes a sensing arm connected to the binding plate adapted to contact the needle cannula, and positionable for restricting movement of the needle cannula.

The biasing member may be disposed adjacent the multi-slot aperture. The interior of the housing may include an angled interior surface for accommodating a portion of the binding plate thereagainst. The multi-slot aperture may include a first region having a first dimension, and a second region having a second dimension, the second dimension being smaller than the first dimension. The biasing member may be adapted to apply a biasing force adjacent the multi-slot aperture in a direction that is substantially perpendicular to a through-axis of the multi-slot aperture.

The sensing arm may include a transverse barrier. The transverse barrier may include a base plate connected to the binding plate and extending in a distal direction from the binding plate. The transverse barrier may also include an engagement plate connected to, and extending from, the base plate in a direction toward a through-axis of the multi-slot aperture. The engagement plate may include a contact surface for contacting a portion of the needle cannula at a location distal from the multi-slot aperture. The contact surface may include an angled restraining lip extending toward the multi-slot aperture. The locking mechanism may be adapted to pivot within the interior of the housing about a pivoting axis to position the sensing arm to restrict movement of the needle cannula. The needle guard may also include a biasing element biasing the binding plate in a distal to proximal direction to bias the binding plate toward a tilted position. The needle guard may further include a second biasing element biasing the binding plate in a direction substantially aligned with the multi-slot aperture.

In another embodiment, a device includes a needle cannula having a cannula tip, and a housing disposed about a portion of the needle cannula. The housing defines an interior, and includes a first port and a second port extending therethrough and aligned along an axis of the housing. The device also includes a locking mechanism disposed within the interior of the housing. The locking mechanism includes a binding plate defining a multi-slot aperture, at least a portion of the multi-slot aperture aligned with the first port and the second port along the axis of the housing. The first port, the second port, and the multi-slot aperture are adapted to receive the needle cannula therethrough. The device also includes a biasing member for biasing the needle cannula within the aperture, the biasing member positionable for restricting movement of the needle cannula in at least a first direction. The device further includes a transverse barrier connected to the binding plate adapted to contact a portion of the needle cannula, and positionable for restricting movement of the needle cannula in a second direction, the second direction being substantially different from the first direction, such as in an opposite direction.

The biasing member may be disposed adjacent the multi-slot aperture. The transverse barrier may include a base plate connected to the binding plate and extending in a distal direction from the binding plate. The transverse barrier may also include an engagement plate connected to, and extending from, the base plate in a direction toward a through-axis of the multi-slot aperture. The engagement plate may include a contact surface for contacting a portion of the needle cannula at a location distal from the multi-slot aperture.

The contact surface may include an angled restraining lip extending toward the multi-slot aperture in a direction that is substantially parallel to the through-axis of the multi-slot aperture. The transverse barrier may include a contact surface, and the transverse barrier is restrained from restricting movement of the needle cannula by contact between the contact surface and the needle cannula. The transverse barrier may be positioned to restrict movement of the needle cannula in the distal direction when contact between the contact surface and the needle cannula is interrupted.

The locking mechanism may be adapted to pivot within the interior of the housing about a pivoting axis to position the sensing arm to restrict movement of the needle cannula. The locking mechanism may be adapted to pivot about the pivoting axis when contact between a contact surface of the sensing arm and the needle cannula is interrupted. The interior of the housing may include an angled interior surface for accommodating a portion of the binding plate thereagainst. The multi-slot aperture may also include a first region having a first dimension, and a second region having a second dimension, the second dimension being smaller than the first dimension.

The biasing member may be adapted to bias the needle cannula against the first port and the second port of the housing in a restrained position, and against at least a portion of the multi-slot aperture in an activated position. The biasing member may also be adapted to advance the needle cannula within the multi-slot aperture from the first region to the second region. The device may also include a biasing element biasing the binding plate in a distal to proximal direction to bias the binding plate toward a tilted position. The needle guard may further include a second biasing element biasing the binding plate in a direction substantially aligned with the multi-slot aperture.

In another embodiment, a method of actuating a needle guard includes the step of providing a needle guard disposed about at least a portion of a needle cannula. The needle guard includes a housing, defining an interior, and having a first port and a second port extending therethrough and aligned along an axis of the housing. The needle guard also includes a locking mechanism disposed within the interior of the housing. The locking mechanism includes a binding plate defining a multi-slot aperture, at least a portion of the multi-slot aperture aligned with the first port and the second port along the axis of the housing. The first port, the second port, and the multi-slot aperture are adapted to receive the needle cannula therethrough. The needle guard further includes a biasing member for biasing the needle cannula within the aperture. The needle guard also includes a sensing arm connected to the binding plate and comprising a contact surface. The sensing arm is adapted to transition from a restrained position in which the contact surface contacts a portion of the needle cannula, to an activated position in which the sensing restricts movement of the needle cannula. The needle guard also includes at least one biasing element for biasing the binding plate in a distal to proximal direction. The method also includes the step of transitioning the sensing arm from the restrained position to the activated position by interrupting contact between the contact surface and the needle cannula.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, the words “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and like spatial terms, if used, shall relate to the described embodiments as oriented in the drawing figures. However, it is to be understood that many alternative variations and embodiments may be assumed except where expressly specified to the contrary. It is also to be understood that the specific devices and embodiments illustrated in the accompanying drawings and described herein are simply exemplary embodiments of the invention.

Referring toFIG. 1, the device20of the present invention includes a housing22, a locking mechanism, such as a needle guard24disposed within the housing22, and a outer needle cannula28also disposed within the housing22and extending through a portion of the needle guard24. The housing22includes a first end30and a second end32opposite the first end30, and defines an interior cavity34therebetween. The first end30defines a first port36, and the second end32defines a second port38substantially aligned with the first port36along a longitudinal axis A of the housing22. The first port36and the second port38may be substantially the same size and may have substantially the same diameter. In another embodiment, one of the first port36and the second port38may be larger than the other of the first port36and the second port38.

In one embodiment, the housing22of the present invention is adapted to accommodate a portion of an outer needle cannula28, having a needle tip29, through the first port36and the second port38. In one embodiment, the first port36and the second port38may have a diameter that is slightly greater than the diameter of the outer needle cannula28. In another embodiment, the first port36and the second port38may have a diameter that is considerably larger than the diameter of the outer needle cannula28. The housing22of the present invention may accommodate a needle cannula having, for example, a diameter of from about 18 G to about 27 G, through the first port36and the second port38. In another embodiment, the housing22of the present invention may accommodate multiple nested needle cannulae through the first port36and the second port38, such as an outer needle cannula28having a needle tip29, and an inner needle cannula26having a needle tip31, nested within the outer needle cannula28. In one embodiment, the outer needle cannula28may be an introducer sheath and the inner needle cannula26may be a smaller diameter needle for delivering fluid to a patient or extracting a fluid from a patient. Alternatively, the inner needle cannula26may include a solid stylet for providing rigidity to an outer needle cannula28. In a further embodiment, the housing22may be adapted for use with conventional gauge “long” needle(s) suitable for spinal, epidural, or anesthesia procedures, and the like. In yet a further embodiment, the housing22may be adapted for use with 18 G-29 G needle cannula.

The housing22may have any suitable dimensions and exterior configurations, provided the first port36, second port38, and at least a portion of the interior cavity34are sufficiently sized to accommodate the outer needle cannula28, and/or nested inner needle cannula26and outer needle cannula28therethrough. In one embodiment, the housing22may have a length L, as shown inFIG. 1, of from about 0.25 inch to about 1.50 inches, a width W, shown inFIG. 1, of from about 0.125 inch to about 1 inch, and a height H, also shown inFIG. 1, of from about 0.25 inch to about 1.50 inches. Although the housing22of the present invention is shown substantially as a substantially rectangular shape with three open sides, it is anticipated herein that the housing22may be fully enclosed, i.e., fully surrounding the interior cavity34, and/or fully enclosed within a separate exterior housing (not shown). It is also contemplated herein that the exterior surface40of the housing22may have any suitable shape, such as rectangular, square, ovoid, trapezoid, and the like. The housing22may be made of any suitable material, such as a substantially rigid polymeric composition. Optionally, the housing22may also include a gripable region having a textured surface and/or texture enhancing coating applied thereto for facilitating a medical practitioner to easily grab the housing22.

The housing22may also include at least one angled interior surface44, such as disposed within the second end32adjacent the second port38. The angled interior surface44may have an angle B of from about 30° to about 60°. The housing22also includes a resistance plate43disposed within the interior cavity34of the housing, such as between the first end30and the second end32. The resistance plate43includes a third port39which is aligned with the first port36and the second port38to allow a cannula to pass therethrough.

The present invention also includes a needle guard24having a binding plate46, a biasing member48and a sensing arm50disposed within the interior cavity34of the housing22. As shown inFIGS. 1-3B, the binding plate46defines a multi-slot aperture52extending therethough. As used herein, the term “multi-slot aperture” means an aperture having a first region having a first dimension, and a second region contiguous with the first region and having a second dimension, as measured in the same orientation as the first dimension, the second dimension being smaller than the first dimension.

For example, as shown inFIGS. 3-3B, the multi-slot aperture52may have a first region54having a first dimension H1, and a second region56having a second dimension H2, the second dimension H2being smaller than the first dimension H1. In addition, the multi-slot aperture52may have a third region62having a third dimension H3, the third dimension H3being smaller than the second dimension H2. Optionally, the first dimension H1, the second dimension H2, and the third dimension H3, each represent the respective heights of the first region54, the second region56and the third region62. Similarly, the multi-slot aperture52may have a first region54having a first opposing dimension L1, and a second region56having a second opposing dimension L2, the second opposing dimension L2being smaller than the first opposing dimension L1, and likewise may have a third region62having a third opposing dimension L3, the third opposing dimension L3being smaller than the second opposing dimension L2. Optionally, the first opposing dimension L1, the second opposing dimension L2, and the third opposing dimension L3, each represent the respective lengths of the first region54, the second region56and the third region62. Alternatively, the multi-slot aperture52may include a first region54having a first dimension H1and a first opposing dimension L1, and a second region56having a second dimension H2and a second opposing dimension L2, with the second dimension H2being smaller than the first dimension H1and the first opposing dimension L1and the second opposing dimension L2being equal.

In yet another embodiment, the first opposing dimension L1, may be equal to or greater than the first dimension H1, the second opposing dimension L2, may be equal to or greater than the second dimension H2, and the third opposing dimension L3, may be equal to or greater than the third dimension H3. It is also anticipated herein, that the multi-slot aperture52may include additional regions, such as a fourth or fifth region (not shown), each respectively having a dimension successively smaller than the previous region. In yet another embodiment, the first dimension H1and the second dimension H2may be selected to be slightly larger than the outer diameter of a target cannula gauge intended to be received therein. For example, the first dimension H1may be dimensioned to receive an outer cannula therein, whereas the second dimension H2may be dimensioned to receive an inner cannula therein and to prevent receipt of an outer cannula therein. In yet another example, the first dimension H1of the first region54may be dimensioned to allow receipt of an 18 G cannula therein, and the second dimension H2of the second region56may be dimensioned to allow receipt of a 22 G cannula therein but not an 18 G cannula.

As shown inFIG. 4, the multi-slot aperture52may include a substantially circular hole portion64which is contiguous with a substantially elongated slot portion66. As shown inFIG. 5, the keyhole region52may include a first substantially circular hole region68having a first diameter D1, a second substantially circular hole region70having a second diameter D2, and a third substantially circular hole region72having a third diameter D3. In this configuration, D3is smaller than D2, and D2is smaller than D1.

Referring toFIG. 2, in one embodiment, the first region54is aligned adjacent a biasing member receiving surface74, such that at least one dimension of the multi-slot aperture52transitions from the biasing member receiving surface74toward the housing alignment surface76in a stepped-down progression. As shown inFIG. 3, the substantially flat surface78may be oriented toward the upper surface82of the binding plate46. In another embodiment, as shown inFIG. 3A, in one embodiment the multi-slot aperture52may include a substantially flat surface78oriented toward the bottom surface80of the binding plate46. In yet another embodiment, shown inFIG. 3B, the first region54transitions to the second region56in a stepped fashion.

The multi-slot aperture52of the present invention is adapted to receive an outer needle cannula28, as shown inFIG. 1, therethrough. In one embodiment, the first region54is adapted to receive an outer needle cannula28therethrough and the second region56is adapted to prevent the outer needle cannula28from being received therein. The second region56, however, may be adapted to receive the inner needle cannula26therein, as will be described.

Referring again toFIGS. 1-2, the needle guard24also includes a biasing member48initially positioned adjacent the multi-slot aperture52, such as initially positioned adjacent the first region54of the multi-slot aperture52. The biasing member48may include any material and/or structure sufficient to impart a biasing force in a direction substantially perpendicular to a through-axis T of the multi-slot aperture52, as shown inFIG. 1. In one embodiment, the biasing member48is connected to the binding plate46at a connection point84. In another embodiment, the biasing member48is restrained against the binding plate46by a portion of the housing22. The biasing member48may be a spring, such as a metal arm having a first portion86adjacent the multi-slot aperture52and a second portion88adjacent the biasing member receiving surface74of the binding plate46.

Referring again toFIGS. 1-3B, the needle guard24also includes a sensing arm50connected to the binding plate46, such as adjacent the upper surface82. In one embodiment, the sensing arm50includes a transverse barrier93adapted to transition from a restrained position, as shown inFIGS. 7-10, to an activated position, as shown inFIGS. 11-12. In one configuration, the transverse barrier93includes a base plate90connected to the binding plate46and extending in a substantially distal direction from the binding plate46. The transverse barrier93may also include an engagement plate92connected to, and extending from, the base plate90. The engagement plate92may extend from the base plate90in a direction toward the through-axis T, shown inFIG. 1, of the multi-slot aperture52. In one embodiment, the engagement plate92may be spaced apart from the binding plate46, a distance of from about 0.125 inch to about 0.5 inch. The binding plate46and the sensing arm50may be co-formed, or separately assembled and subsequently joined. In a further embodiment, the engagement plate92includes a contact surface94aligned with the through-axis T of the multi-slot aperture52. In yet a further embodiment, the contact surface94includes an angled restraining lip96extending toward the multi-slot aperture52in a direction substantially parallel to the through-axis T of the multi-slot aperture52.

Referring yet again toFIGS. 1-2, a biasing element41is also disposed between a portion of the housing22, such as a portion of the resistance plate43, and a portion of the needle guard24, such as a portion of the binding plate46. The biasing element41may also be disposed between a portion of the resistance plate43and a portion of the biasing member48connected to the binding plate46. The biasing element41biases a lower portion of the needle guard24, such as lower portion46A of the binding plate46, against the housing in a direction parallel to the longitudinal axis A of the housing22. This biasing force is balanced by the force applied to the needle cannula28by the contact from contact surface94of the sensing arm50and the reaction force of a portion of the housing22, such as rearward portion104, at a pivot P, as shown inFIG. 8. The biasing element41may include a compression spring, a leaf spring, a compressible material, a magnetic material having a magnetic interaction with a portion of the housing22, such as the second end32, or other similar biasing structure. Alternatively, the biasing element41may be a torsion spring disposed between a lower portion46A of the binding plate46and a portion of the housing22, such as the resistance plate43. In this configuration, the biasing element41applies a torque to the binding plate46. In yet another embodiment, the biasing element41may be disposed to impart a biasing force on a different or additional portion of the needle guard24, such as disposed to impart a biasing force in a downwardly directed orientation on at least a portion of the base plate90.

The device20ofFIG. 1is shown in the assembled view inFIG. 6. It is noted herein that the device20shown inFIGS. 1 and 6may include an exterior housing (not shown) which surrounds the device20. As shown inFIG. 6, the needle guard24is disposed within the interior cavity34of the housing22, and an outer needle cannula28is disposed through the first port36, the second port38, and the third port39of the housing22. At least a portion of the multi-slot aperture is aligned with the first port36, the second port38, and the third port39along the axis A of the housing22, such that the outer needle cannula28may also extend through at least a portion of the multi-slot aperture52. In this orientation, the biasing member48is restrained by affixation to the binding plate46or by an interior portion of the housing22, and biases the outer needle cannula28within the multi-slot aperture52. The biasing element41is compressed between a portion of the resistance plate43and the binding plate46. Also in this orientation, the contact surface94of the sensing arm50is adapted to contact a portion of the outer needle cannula28. In one embodiment, the contact surface94of the sensing arm50is adapted to contact a portion of the outer needle cannula28at a location distal from the multi-slot aperture52.

The needle guard24of the present invention is adapted to transition from a restrained position, shown inFIGS. 7-8B, to an intermediate restrained position, shown inFIGS. 9-10B, to an activated position, shown inFIGS. 11-12A. Optionally, the needle guard24may be adapted to transition from the restrained position, shown inFIGS. 7-8B, to the activated position, shown inFIGS. 11-12A, without first transitioning to an intermediate restrained position, shown inFIGS. 9-10B. In another embodiment, the needle guard24may be adapted to transition from the intermediate restrained position, shown inFIGS. 9-10B, to the activated position, shown inFIGS. 11-12A, without first transitioning from the restrained position, shown inFIGS. 7-8B, depending on the relevant cannula gauge employed therein. As shown inFIGS. 7-8B, the outer needle cannula28is disposed through the first region54of the multi-slot aperture52, shown inFIG. 3, and through both first port36and the second port38, and the third port39of the resistance plate43of the housing22. The inner needle cannula26may be disposed within the outer needle cannula28. The needle guard24of the present invention is intended to be disposed on at least a portion of an outer needle cannula28, in a restrained position, during the performance of a standard medical procedure. In the restrained position, the needle tip29of the outer needle cannula28may be generally exposed. The contact surface94of the sensing arm50contacts the needle cannula surface100. As shown inFIGS. 8A and 8B, the biasing member48biases the outer needle cannula28(with the inner needle cannula26nested therein) within the first region54of the multi-slot aperture52. As the multi-slot aperture52is dimensioned to allow the outer needle cannula28to be disposed within the first region54, but not the second region56, the biasing member48creates a continuous pressure of the cannula surface100against a portion of the multi-slot aperture52separating the first region54and the second region56. Referring again toFIGS. 7-8B, the biasing element41, disposed between the resistance plate43and the needle guard24biases the lower portion46A of the binding plate46toward the second end32of the housing22. The needle guard24is held in a stationary position from the corresponding force applied by the contact between the outer surface100of the outer needle cannula28and the contact surface94of the sensing arm50.

After or during a medical procedure, it may be desirable to advance the needle guard24over the outer needle cannula28onto an inner needle cannula28. Optionally, it may be desirable to fully withdraw the outer needle cannula28or to advance the needle guard24over the needle tip29of the outer needle cannula28along the inner needle cannula26. In one embodiment, the advancement of the needle guard24can occur while the needle tip31of the inner needle cannula26is inside the patient. Alternatively, advancement of the needle guard24can occur once the needle tip31on the inner cannula26has been removed from the patient.

As shown inFIGS. 9-10B, as the needle guard24is advanced over the needle tip29of the outer needle cannula28, the contact surface94of the sensing arm50drops toward the through-axis T of the multi-slot aperture52, shown inFIG. 1, until contact with the needle cannula surface102of the inner needle cannula26is made. As shown inFIGS. 9-10B, once the needle guard24is transitioned from an outer cannula28to an inner cannula26, the needle guard is in the intermediate restrained position. Once the larger diameter outer needle cannula28is removed from the multi-slot aperture52, the biasing member48advances the inner needle cannula26into the smaller dimensioned second region56of the multi-slot aperture52, as shown inFIG. 10A. If sizing of the first region54, second region56and third region62in relation to the cannula28permit, the cannula28may pass from the second region56into the third region62. In a further configuration, the outer cannula28may be initially disposed within the second region56, and the inner cannula26nested therein may become disposed within the third region62once the outer cannula28is removed thereover. The needle guard24is then held in a stationary position from the corresponding force applied by the contact between the outer surface102of the inner needle cannula26and the contact surface94of the sensing arm50. As shown inFIGS. 10A and 10B, the biasing member48biases the inner needle cannula26within a second region56of the multi-slot aperture52. As shown inFIG. 10B, a portion of the biasing member48is visible through the third port39of the resistance plate43.

As shown inFIGS. 11-12A, once the medical procedure is complete, the needle guard may be advanced over the needle tip31of the inner needle cannula26. The sensing arm50of the needle guard24is positionable for restricting movement of the needle cannula, such as the inner needle cannula26. In the restrained or intermediate restrained position, shown inFIGS. 7-10B, the sensing arm50is restrained from restricting movement of the inner needle cannula26by contact between the contact surface94and the needle cannula surface102. As shown inFIGS. 11-12A, as the inner needle cannula26is pulled in a proximal direction, the needle tip31passes beyond the sensing arm50and contact between the contact surface94and the needle cannula surface102is interrupted.

Once contact between the needle cannula surface102and the contact surface94of the sensing arm50is interrupted, the sensing arm50drops at least partially below the through-axis T of the multi-slot aperture52and the sensing arm50, the binding plate46and the biasing member48pivot within the interior cavity34of the housing22about a pivot axis. Once the reaction force caused by contact between the contact surface94of the sensing arm50and the needle cannula28is disrupted, the biasing force of the biasing member41forces the lower portion46A of the binding plate46away from the resistance plate43. In another embodiment, the biasing member41forces the lower portion46A of the binding plate46toward the rearward portion104of the housing22, such as about pivot P, such that the binding plate46becomes tilted with respect to its initial position, shown inFIGS. 7-9B.

This pivoting motion advances the sensing arm50, particularly the engagement plate92, in a downward direction toward the through axis T of the housing22and occludes the first port36to restrict the movement of the inner needle cannula26in the distal direction. In one embodiment, the binding plate46tilts until both the top and bottom edge of the multi-slot aperture52make contact with the corresponding top and bottom of the inner cannula26(or outer cannula28). This tilt angle is typically from about 5° to about 10°, depending on the dimensional relationship between the cannula26,28and the multi-slot aperture52. The tilt of the binding plate46is observed once transitioned to the initial activated position. If additional force is applied to a needle cannula26disposed within the binding plate46in a direction substantially proximal to the needle guard24, the tilt of the binding plate46may be increased until a rearward portion104of the binding plate46may be aligned with or contacts at least a portion of the angled interior surface44of the housing22, or optionally another portion of the housing22, at this maximum tilt, when the needle guard24is heavily loaded, such as during the application of force in a proximal direction after transition to the activated position. The frictional resistance between the inner cannula26and the tilted binding plate46prevents removal of the inner cannula26from the needle guard24in the proximal direction absent intentionally applied malicious force. Optionally, a portion of the inner cannula26may be deformed against a portion of the binding plate46during transition to the activated position and/or during application of applied force on the needle cannula26in the proximal direction after transition to the activated position.

Accordingly, the locking mechanism of the needle guard24of the present invention is capable of restraining the tip of a needle in a distal direction by transitioning the sensing arm50from the restrained position to the activated position. The locking mechanism of the needle guard24of the present invention is also capable of restraining the tip of a needle in the proximal direction by effectively binding and jamming the tilted binding plate46against the needle cannula26.

The needle guard24of the present invention can effectively “jump” from a larger diameter outer needle cannula28to a smaller diameter inner needle cannula26, without transitioning from the restrained position, as shown inFIGS. 7-10B, to the activated position, shown inFIGS. 11-12A. When the needle guard24is advanced over the needle tip29of the outer needle cannula28, the sensing arm50contacts the needle cannula surface102of the inner needle cannula26, thereby preventing transition to the activated position. In another embodiment, it is contemplated herein that multiple nested needle cannulas, such as three, four, or five needle cannulas, may be used with the needle guard of the present invention. Alternatively, the needle guard24of the present invention may be used with a single needle cannula and/or solid stylet.

A beneficial aspect of producing a needle guard24adapted to receive a plurality of varying cannula gauges is a significant decrease in the associated production expenses, as the amount of tooling and fabrication inventory is decreased. By utilizing a needle guard24that accommodates many different needle or cannula gauges, the number of different types of needle guards that are needed is significantly reduced.

In an alternative embodiment of the present invention, as shown inFIGS. 13-13B, the needle guard124is similarly described above and disposed within an interior of the housing122. In addition to biasing element141, described above with reference to element41, a second biasing element142is disposed between a portion of the interior of the housing122and the needle guard124. The second biasing element142may include a compression spring, a leaf spring, a compressible material, a magnetic material having a magnetic interaction with a portion of the housing122, or other similar biasing structure.

In one embodiment, the second biasing element142is disposed between an interior wall125of the housing122and a portion of the binding plate144having a multi-slot aperture152disposed therein. A nested outer cannula128and inner cannula126may be disposed through a first port160, a second port162and a third port164of the housing. The outer cannula128may also be disposed within a portion of the multi-slot aperture152, such as through a first region154. The second biasing element142biases the binding plate144, such as a portion of the multi-slot aperture152against a portion of the outer cannula128. In one embodiment, the outer gauge of the outer cannula128may contact the multi-slot aperture152between a first region154and a second region156. The second biasing element142is held in a biased state by the physical interaction between the outer cannula128and the second region156of the multi-slot aperture152, which has a dimension smaller than the outer dimension of the outer cannula128. In one configuration, the first biasing element biases the binding plate144in the distal to proximal direction along the longitudinal axis A, shown inFIG. 1, to bias the binding plate144toward a tilted position. As discussed above, the interaction of the contact surface194of the sensing arm150and the outer cannula128prevents the first biasing element141from tilting the binding plate144. In another embodiment, the second biasing element142biases the binding plate144in a direction substantially perpendicular to the bias of the first binding element141. In one embodiment, the second biasing element142biases the binding plate144in a direction that is substantially aligned with the multi-slot aperture152such that a portion of the multi-slot aperture152engages the outer cannula128disposed therein.

As shown inFIGS. 14-14B, when the outer cannula128is removed from the housing122, or removed from the third port164of the housing122, the inner cannula126having a smaller diameter than the outer cannula128is disposed within the multi-slot aperture152, as described herein. In this configuration, the second biasing element142advances the binding plate144, specifically the multi-slot aperture152of the binding plate144away from the interior wall125of the housing122in the direction of the bias of the second biasing element142. As the outer diameter of the inner cannula126is smaller than the outer diameter of the outer cannula128, the multi-slot aperture152is advanced such that the inner cannula is disposed within a second region156. As shown inFIGS. 14-14B, the entire needle guard124is shifted with respect to the housing122in the intermediate restricted position, as compared to the initial restricted position, shown inFIGS. 13-13B.

As shown inFIGS. 15-15B, once the needle tip127of the inner cannula126is passed within the interior of the housing122, the needle guard124tilts forward and the engagement plate192drops downward to prevent distal movement of the needle tip, as similarly described herein. Simultaneously, the first biasing element141tilts the binding plate144thereby binding and jamming the inner cannula126, as also similarly described herein.

While the present invention is described with reference to several distinct embodiments of a needle guard and method of use, those skilled in the art may make modifications and alterations without departing from the scope and spirit. Accordingly, the above detailed description is intended to be illustrative rather than restrictive.