WO2005032629A1

WO2005032629A1 - Improved syringe safety device

Info

Publication number: WO2005032629A1
Application number: PCT/AU2004/001366
Authority: WO
Inventors: David Wearne; Gary Conwell; Mario Giuseppe Sticca
Original assignee: MEDICAL SAFETY DEVICES Pty Ltd
Current assignee: MEDICAL SAFETY DEVICES Pty Ltd
Priority date: 2003-10-08
Filing date: 2004-10-07
Publication date: 2005-04-14
Anticipated expiration: 2006-04-08

Abstract

A syringe safety device (20) suitable for disposal of a single syringe (19) having a needle and barrel, the safety device including: a) a syringe barrel encapsulating portion (21); and b) a needle encapsulating portion (22), having a longitudinal axis extending from an open end to a closed end thereof, wherein said syringe barrel encapsulating portion (21) has an open end for insertion of a syringe therein and a opposed end communicating said syringe barrel encapsulating portion, and wherein said needle encapsulating portion (22) has an interior face (23, 24, 25) disposed in a plane extending towards the longitudinal axis of the needle encapsulating portion at an angle non-perpendicular to said axis for increasing the probability of said needle undergoing destructive impact during insertion of the syringe into the device.

Description

IMPROVED SYRINGE SAFETY DEVICE FIELD OF THE INVENTION This invention relates to a syringe safety device and, in particular, to a device suitable for encapsulation and disposal of a single syringe. PRIOR ART The hazards of used needles are now well recognised. It is well known that a number of diseases may be transmitted by reuse of syringes. For example, the transmission of AIDS and Hepatitis viruses such as Hepatitis C through reuse of needles is now well documented. Transmission of disease is not only possible through reuse of needles but indeed may be caused by so called needle stick injury in which a needle inadvertently punctures the skin of a person allowing transmission of a virus to that person. A number of proposals for dealing with such hazards have been documented in the patent literature. For example, French Patent No. 2650511 describes a syringe protection device which is intended to facilitate preparation of injections. The device is also intended to eliminate the risk of pricking injuries as well as the possible recovery of the used syringes. Most such proposals are predicated on use in a therapeutic environment in which many needles are used on a daily basis and a centralised disposal unit may readily be used for the purpose of needle disposal. In such environments, the risk of reuse is relatively small and the prime concern is to ensure that disease transmission through needle stick injury does not occur. A number of technologies for needle destruction and/or containment are known. Grinding, melt-fusion and other technologies are available which confine used needles in a safe environment subsequent to other disposal steps. Real hazards remain, however in the non-therapeutic environment where availability of a centralised needle disposal system is problematic. Even if such disposal facility is available there remains the problem that accidents may occur while conveying a used needle to the disposal facility. It is understood that while there has been a dramatic increase in the number of syringes distributed and collected from disposal units with different sharps containers, surveys have indicated that a major problem with needle syringe exchange programs is availability of disposal units on both a locality and time frame basis. Therefore, it is in the interest of public health for more needle disposal options to be available to drug users to minimize hazards to the general community through disease transmission as above described. Such disposal options should be suitable for safe disposal of single syringes after a single use. In that way, the disposal system interfaces well with the needle exchange program. One device previously proposed to address problems associated with the aforementioned prior art is disclosed in WO 01/78806. This document discusses a syringe retaining device suitable for disposal of a single syringe with its associated needle. This syringe disposal device incorporates a stepped configuration towards the closed end thereof. The stepped arrangement is intended to increase the probability of a needle undergoing a destructive impact during insertion of the needle into the device due to the number of steps. Although this device may render the needle unusable due to bending under impact with one of the steps, problems may occur with this device. For example, it has been found in some instances, that the section of needle between the tip and bend in the needle shaft can bridge from one step, across the internal width known to an opposite step of the device. Subsequently, the remaining section of needle between the bend and the syringe has been shown to exhibit sufficient flexural rigidity, to resist further bending along its length. Thus complete insertion of the syringe into the disposal device may be prevented under practical insertion forces. This can result in a "spring" effect due to increased bend strength in the needle shaft as a result of the shortened length. That is, the portion o f the needle between the bend and the syringe may be sufficiently short in length that an insertion force applied to the syringe is normally insufficient to create a subsequent bend in the needle shaft or to force the bend in the needle past the step. Further, if the needle tip impinges upon one of the steps, the syringe barrel can be forced sideways relative to the longitudinal axis of the disposal device. Subsequently, a shoulder or side of the syringe barrel may contact an inside face of the syringe barrel retaining portion or initial stepped portion of the disposal device such that the syringe is prevented from further insertion into the device. If a syringe is not fully inserted into the disposal device, and unsafe disposal practices result. If sideways motion of the syringe occurs, the needle may not undergo sufficient destructive bending or buckling to prevent the possibility of reuse of the needle. With the aforementioned characterisation of the prior art in view, it is an object of the present invention to provide a syringe safety device which increases the probability of destructive bending or buckling of a syringe needle to help reduce the possibility of reuse of the needle. SUMMARY OF THE INVENTION With the aforementioned object in view, the present invention provides a syringe safety device suitable for disposal of a single syringe having a needle and barrel, the safety device including: a) a syringe barrel encapsulating portion; and b) a needle encapsulating portion, having a longitudinal axis extending from an open end to a closed end thereof; wherein said syringe barrel encapsulating portion has an open end for insertion of a syringe therein and an opposed end communicating said syringe barrel encapsulating portion with said needle encapsulating portion, and wherein said needle encapsulating portion has an interior facing surface including at least one needle impacting face disposed in a plane extending towards the longitudinal axis of the needle encapsulating portion at an angle non-perpendicular to said axis for increasing the probability of said needle undergoing destructive impact during insertion of the syringe into the device. By a plane extending towards the longitudinal axis is meant that the or each of the faces is disposed non-perpendicular and non-parallel to the longitudinal axis of the needle encapsulating portion. For example, a series of needle impacting faces may be provided that taper towards a central axis of the needle encapsulating portion. It is envisaged that the or each impact faces may lie in a flat or curvilinear plane eg concave impact face(s) or in combination of flat or curved planar face(s). According to a preferred embodiment of the present invention, the at least one needle impacting face may be a series of faces arranged at intervals along the length of the needle encapsulating portion. These advantageously may help to further increase the probability of bending or buckling of the needle. Preferably the needle undergoes multiple bending or buckling. By "bending" or "buckling", it is intended that the device causes the needle shaft to yield at one or more than one point along its length resulting in a permanent deformation of the needle. This helps to ensure that the syringe can be fully and safely inserted into the safety device whilst helping to ensure that the needle is reduced to a non-reusable condition. In one preferred form of the present invention, the needle encapsulating portion includes needle impacting faces formed as a series of chamfered or angled faces. These may be arranged such that when the tip of the needle impinges upon one of these faces, and the needle bends or buckles due to the continuing force applied to the needle shaft via the syringe body, the point of bending or buckling of the needle shaft does not impinge upon an opposite angled face. Thus, the section of needle between a bend and the syringe is permitted to continue a motion towards the closed end of the needle encapsulating portion during insertion to enable the syringe to be fully inserted into the device. The chamfered or angled needle impacting faces may further help to reduce the probability of the barrel of the syringe from contacting a side wall of the device. This advantage is seen in that the reduced probability of the needle impinging upon a discrete step in the inner face of the needle encapsulating portion which may otherwise force the barrel sideways to contact the side wall. In a most advantageous form of the present invention, one or more chamfered or angled needle impacting faces may be formed as a one or more spiral or helical grooves or channels formed in the surface of the of the needle encapsulating portion. Alternatively, the grooves or channels may be sections of spirals or helixes. In this form of the invention, a needle impinging upon a portion of the spiral may be caused to destructively bend or buckle due to an applied force. By "destructive" or "destructively" is meant that the needle is rendered non- reusable. The bent portion of the needle is thus permitted to follow the path of the spiral towards the closed end of the needle encapsulating portion or to bend away from the spiral step. If the point of bend or buckle in the needle impinges upon an opposite portion of the spiral step, the downward slope of the spiral permits the point of bend of the needle to continue towards the closed end of the needle encapsulating portion thus permitting the syringe to be fully inserted into the device and/or to allow a further buckling or bending of the needle between the initial bend/buckling point and the syringe end of a needle. A further preferred embodiment of the present invention provides one or more spiral or helical ridges, or ridge sections, running along an interior facing surface of the needle encapsulating portion. The ridge or ridges extend towards the longitudinal centre axis of the needle encapsulating portion and form(s) or include(s) the needle impacting face(s). In an alternative form of the present invention the projection portions may be formed on a ziggurat arrangement extending from the closed end of the needle encapsulating portion. The angled or chamfered needle impacting faces form sloping steps of the ziggurat. An alternative form of the present invention incorporates an inverted "Christmas tree" arrangement extending from the closed end of the needle encapsulating portion. Advantageously, the recesses or grooves formed by the angled faces help to trap a needle tip thus assisting bending of the needle. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the following description made with reference to the following drawings in which: Figure 1 shows a side section of a syringe disposal device of the prior art; Figure 2 shows a side section of a syringe safety device in accordance with an embodiment of the present invention; Figures 3a and 3b show further views of a side section of a syringe disposal device according to the prior art of Figure 1 including a syringe and needle; Figures 4a and 4b show side section views of a syringe safety device in accordance with an embodiment of the present invention as shown in Figure 2 including a syringe and needle; Figure 5 shows a sectional view of a preferred embodiment of the present invention incorporating a series of inverted projection portions; Figure 6 shows a further preferred embodiment according to the present invention including a ziggurat arrangement; Figure 7 shows a horizontal cross-section through the embodiment shown in Figure 5; Figure 8 shows a sectional view of a further embodiment of the present invention including a spiral or helical channel or groove; Figure 9 shows a further sectional view of the embodiment shown in Figure 8 with a syringe and needle inserted therein; Figure 10 shows an alternative form of the embodiment shown in Figure 8 and 9, with a spiral ridge. Figures 11 and 12 show cutaway views of further alternative embodiments of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT Referring to Figure 1 of the drawings, there is shown a syringe disposal device (10) according to the prior art. The syringe disposal device (10) includes a syringe barrel encapsulating portion (11) and a syringe needle encapsulating portion (12). The inner surface of the needle encapsulating portion includes a stepped configuration including discrete steps (13), (14) and (15). Although the probability of a needle undergoing a destructive impact increases due to the presence of the steps over a needle encapsulating portion having a continuous smooth tapered inner surface due to the presence of the steps, the probability of jamming of the needle and syringe in the device also increase. For example, as shown in Figure 3a impinging upon one of the discrete steps of the prior art device (10) can undergo bending or buckling at a first position along the shaft of a needle (17) impinging upon one the discrete steps of the prior art device can bend at a first point (18) along its length such that the portion of the shaft of the needle between the point of the needle impinging upon the step and the bend point can bridge the opening into the needle encapsulating portion (12) of the device (10). This bridging can result in a "spring" effect in the remaining portion of the needle shaft between the bend point (18) and the syringe (19).

Subsequent insertion force applied to the syringe is resisted by the increased flexural rigidity of the remaining portion of the needle due to its effect shortened length relative to its width. Effective shortened length of the needle portion (17) is a direct result of contact of the needle at a point bridging the opening of the needle encapsulating portion (12) and extending to the syringe (19). Thus a syringe and needle inserted into the prior art device (10) shown in Figure 3a can be prevented from for insertion by unexpected and non-beneficial bending of the needle. However, the device according to the present invention, and as shown in the embodiment in Figure 2, incorporates angled face portions (23), (24) and (25) rather than discrete steps (13), (14) and (15) of the prior art. The illustrated angled faces (23), (24) and (25) of the syringe safety device (20) decrease the probability of a bent or buckled needle from bridging the opening of the needle encapsulating portion (22). Thus, the bent portion (28) of the needle can pass the opening of the needle encapsulating portion and subsequently the likelihood of bridging of the needle encapsulating portion and the associated spring effect due to the remaining portion (27) of the needle shaft are reduced such that the syringe and needle can be safely and completely inserted into the syringe safety device whilst helping to ensure the needle becomes non-reusable due to destructive forces. It will be appreciated that the angled face(s) present a larger apparent impact surface area to a needle being inserted into the device in comparison with the known stepped device. Thus the probability of a needle undergoing destructive impact is increased (see for example Figures 1 and 3a). A further problem associated with known devices is found in that the syringe body (19) can be forced sideways relative to the length of the device (10) as a result of the needle impinging upon one of the discrete steps (13), (14) or (15). Due to the nature of the steps (13), (14) or (15) it has been found on occasion that the needle will resist bending sufficiently that a bend or buckle does not occur in the shaft of the needle rather the body of the syringe is caused to move sideways relative to the longitudinal axis of the device and, and as a result, the syringe cannot be fully inserted into the device due to one or more shoulders of the syringe body (19) impinging upon a portion of the needle encapsulating portion at the opening thereof. Figure 4a shows an embodiment according to the present invention whereby, due to the chamfered or angled faces (23), (24) or (25), the bend (28) in the needle shaft has additional clearance in which to pass into the width of the needle encapsulating portion. Thereby, the probability of the syringe body being forced sideways relative to the longitudinal axis of the device is greatly reduced with the result that the syringe is more easily and more efficiently fully inserted into the syringe safety device, greatly enhancing safety and ease of use. Figure 4b shows the syringe fully inserted into its final safe position in the syringe safety device. The angled faces have permitted the bent (destructed) needle to pass into needle encapsulating portion, whereas, as shown in Figure 3b, the bent needle can be prevented in prior art devices from folding into the needle encapsulating portion by bridging the step14. Thus, the prior art device of Figure 3a, 3b can prevent the syringe from being completely inserted into its safe position. A further advantage of the present invention, as illustrated in the embodiment shown in Figure 4b, is that an angled face eg 23 permits syringes of different leading diameters to be retained. That is, the angled face acts as a tapered guide and does not limit the syringe safety device to accepting syringes of a particular diameter or smaller. Figure 5 shows a further preferred form of the syringe safety device (30) according to the present invention. According to this particular embodiment, projecting portions are arranged in the form of a body (31) extending from the closed and of the needle encapsulating portion (32) towards the open end of the needle encapsulating portion adjoining the syringe barrel encapsulating potion (33). The projecting body (31) is, in this arrangement, in the form of an inverted "Christmas tree" arrangement. This arrangement incorporates multiple projecting portions (34), (35), (36) and (37) having multiple angled faces (34a), (35a) and (36a) forming the sides of the respective channels formed by the projecting portions (34), (35), (36) and (37). The apex (37) of the "Christmas tree" includes angled faces (37a). It will be appreciated that although Figure 5 shows a cross- sectional view of this preferred embodiment, the projecting body (Christmas tree) (31) can be circular, square, hexagonal, or other form or combination of regular or irregular polygons when a horizontal section is taken through the syringe safety device, as shown in Figure 7. For example, Figure 7 shows a transverse cross- sectional view of the embodiment shown in Figure 5 through the section at line AA. The preferred embodiment shown in Figure 6 incorporates the projecting body (41) in the form of a ziggurat having chamfered needle impact face(s) (43) and (44). The projecting body extends from the closed end of the needle encapsulating portion (42) towards the open end of the needle encapsulating portion (42) adjacent the syringe barrel encapsulating portion (45) of the device. A further preferred form of the present invention is shown in Figure 8. The syringe safety device (50) in this embodiment includes a spiral groove or channel (51) extending around the inner face of the needle encapsulating portion (52) the spiral groove or channel (51) incorporates a chamfered or angled face (53) such that a needle will be caused to suffer destructive bending or buckling along the length thereof as a result of the needle tip impacting upon one of the chamfered faces (53) of the spiral groove or channel (51). As a result, continued applied insertion forces will cause the needle to bend or buckle as shown in Figure 9. An alternative preferred embodiment of the present invention provides needle impact faces arranged as a continuous or broken spiral or helix channel or groove in the interior side wall of the needle encapsulating portion of the syringe safety device. For example, a broken spiral of helix may be formed by an otherwise continuous spiral/helix having slots to divide the spiral/helix into multiple portions thereof. Figure 9 shows a section view of the syringe safety device according to the embodiment shown in Figure 8 with a syringe inserted therein. The syringe (64) includes a needle (65). In Figure 9, the needle (65) is shown having impinged upon a chamfered face (63) of the spiral groove or channel (61). As shown, due to the destructive impact, the needle (65) has a bend point (66) along the shaft thereof such that the needle is reduced to a non-reusable condition. In accordance with the present invention, the provision of one or more faces arranged non-perpendicular and non-parallel to a longitudinal axis extending from the needle encapsulating portion in communication with a syringe barrel encapsulating portion and a closed end of the needle encapsulating portion substantially increases the probability that the needle will undergo destructive impact whilst still permitting the syringe (64) to be fully and safely inserted into the device (60). The "spring" effect problem caused by the effectively shortened needle shaft is reduced as a result of the bend (66) in the needle being able to pass the chamfered face (63) of the spiral groove or channel (61). For example, with regard to a known device, when a section of a bent needle between the tip and a first bend point bridges from a first discrete step to an opposite discrete step, the remaining section of the needle from the bend point to the syringe can have sufficient bend strength to prevent a second or subsequent bend in the needle shaft. In such a known device, the extent of the rectilinear type impact steps towards the centre of the device have been found to prevent full insertion of the syringe and needle into the device. However, as shown in the embodiment depicted in Figures 2 and 4a, 4b, the angled impact faces of the present invention provide a reduced intrusion towards the centre of the needle encapsulating portion, and thus, increased clearance for the bend portion of the needle to pass into the cavity of the encapsulating portion. The likelihood of the bent or buckled needle bridging from one portion of the spiral across the needle encapsulating portion (62) of the device (60) is reduced. Subsequently the probability of the shortened effective needle shaft providing sufficient resistance due to increased flexural rigidity as a result of the shortened length is reduced. An alternative form of this embodiment provides a spiral or helical portion extending towards the centre of from the interior of the needle encapsulating portion i.e. forming a ridge rather than a groove or channel, as shown in Figure 10. However, a combination of groove(s)/channel(s) and ridge(s) also envisaged. The embodiment shown in Figure 10 includes a spiral or helical ridge (72) running around the interior surface of the needle encapsulating portion of the device. The ridge (72) includes angled or chamfered faces (73) on which a needle tip can impinge. As with the embodiment shown in Figures 8 and 9, the arrangement of angled of chamfered faces allows a bend in the needle resulting from destructive impingement upon one of the angled or sloping faces to pass an opposite angled or chamfered face. Thus, the device helps to reduce the probability of jamming of the needle in the device and thus promotes safe and efficient use. An alternative form of this embodiment includes sections of a spiral or helix each incorporating one or more needle impact faces. It will be appreciated that embodiments of the invention having the grove/ channel or ridge arrangement may include more than one of such grooves/ channels or ridges i.e. double helix or spiral. Figure 11 shows alternative embodiments of the present invention. In particular, the needle encapsulating portion (81) of the device (80) may include one or more curved needle impact faces (82). Such curved faces may be solely concave or convex, or a combination of both concave and convex planes. For example, Figure 12 shows a syringe safety device according to alternative embodiments of the present invention including convex impact faces (92) on one section of the cutaway view and combination faces (93) on an opposite section of the same view of the device (90). It will be appreciated that one or more impact faces according to any of the embodiments discussed can be provided on an interior facing surface of the syringe barrel encapsulating device.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A syringe safety device suitable for disposal of a single syringe having a needle and barrel, the safety device including: a) a syringe barrel encapsulating portion; and b) a needle encapsulating portion, having a longitudinal axis extending from an open end to a closed end thereof; wherein said syringe barrel encapsulating portion has an open end for insertion of a syringe therein and an opposed end communicating said syringe barrel encapsulating portion with said needle encapsulating portion, and wherein said needle encapsulating portion has an interior facing surface including at least one needle impacting face disposed in a plane extending towards the longitudinal axis of the needle encapsulating portion at an angle non-perpendicular to said axis for increasing the probability of said needle undergoing destructive impact during insertion of the syringe into the device.

2. A syringe safety device as claimed in claim 1 , wherein the or each impact faces lie(s) in a flat or curvilinear plane or in a combination of flat or curved planar face(s).

3. A syringe safety device as claimed in claim 1 or 2, wherein the at least one needle impacting face may be a series of faces arranged at intervals along the length of the needle encapsulating portion.

4. A syringe safety device as claimed in any one of the preceding claims, wherein said at least one needle impacting face is/are arranged such that the needle undergoes multiple being or buckling.

5. A syringe safety device as claimed in any one of the preceding claims, wherein the needle encapsulating portion includes needle impacting faces formed as a series of chamfered or angled faces.

6. A syringe safety device as claimed in claim 5, wherein the needle impacting faces are arranged such that when the tip of the needle impinges upon one of these faces, and the needle bends or buckles due to the continuing force applied to the needle shaft via the syringe body, the point of bending or buckling of the needle shaft does not impinge upon an opposite angled face.

7. A syringe safety device as claimed in claim 5 or 6, wherein the one or more chamfered or angled needle impacting faces may be formed as a one or more spiral or helical grooves or channels formed in the surface of the of the needle encapsulating portion.

8. A syringe safety device as claimed in claim 7, wherein the grooves or channels are sections of spirals or helixes.

9. A syringe safety device as claimed in any one of the preceding claims, including one or more spiral or helical ridges, or ridge sections, running along an interior facing surface of the needle encapsulating portion, the ridge or ridges extending towards the longitudinal centre axis of the needle encapsulating portion and form(s) or include(s) the needle impacting face(s).

10. A syringe safety device as claimed in any one of the preceding claims, wherein the at least one needle impacting face is formed on a stepped arrangement extending from the closed end of the needle encapsulating portion.

11. A syringe safety device as claimed in claim 10, wherein the stepped arrangement includes angled or chamfered needle impacting faces form sloping steps.