WO2009059357A1

WO2009059357A1 - A medical tool and a method of injecting a fluid

Info

Publication number: WO2009059357A1
Application number: PCT/AU2008/001636
Authority: WO
Inventors: Srilakshmi Sharma; Michael Cornish
Original assignee: Srilakshmi Sharma; Michael Cornish
Priority date: 2007-11-05
Filing date: 2008-11-03
Publication date: 2009-05-14

Abstract

A medical tool (10) for minimising post injection liquid reflux from a needle entry point in an injection surface. The tool has a resilient seal that allows a needle to pass through from a proximal side to a distal side. The seal is moveable relative to the needle to move the distal side into contact with an injection surface (3). The seal deforms when the needle is removed from the injection surface and the distal side of the seal, such that the needle entry point (2) is sealed.

Description

Description A MEDICAL TOOL AND A METHOD OF INJECTING A FLUID

FIELD OF THE INVENTION

The present invention relates to medical tools associated with the injection of fluids, and in particular, medical tools for minimising fluid flow from needle entry points.

The invention has been developed primarily for use in intravitreal injection procedures. However, it will be appreciated that the invention is not limited to this particular use. For example, the invention can be used elsewhere on the body where fluids of any type are to be injected.

BACKGROUND OF THE INVENTION

Any discussion of the prior art throughout this specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Intravitreal injection, or injection into the eye, of certain drugs is a highly successful form of direct and local drug delivery for specific disease states. The benefits to patients include: restoration of vision, reduction of inflammation, regression of neovascularisation (m diabetes), reduction of exudation m age related macular degeneration (ARMD) and a lack of systemic side effects. The diseases noted are extremely common. For instance, macular degeneration and diabetes are the two of the most common causes of blindness in western countries. Other diseases and conditions where treatment involves the injection of materials into the eye include choroidal neovascularisation (CNV), retinopathies (e.g. diabetic retinopathy, vitreoretinopathy), retinitis (e.g. cytomegalovirus (CMV) retinitis), uveitis, macular edema, glaucoma, and neuropathies.

One problem associated with intravitreal injection is the reflux of drugs injected into the eye, specifically into the vitreous humour, which is m the posterior compartment of the eye. In particular, there is often reflux of some drugs through the needle entry site as the needle is withdrawn and after it has been withdrawn. This resulting loss of drug has been shown m studies.

Therefore, the actual amount of drug instilled into the eye is unknown. If the amount of drug entering the eye is unknown or cannot be guaranteed, patients may be subjected to additional and unnecessary invasive procedures. This is undesirable as intravitreal injections can carry with them infrequent but significant complications, most notably infectious endophthalmitis, a potentially blinding condition. The quoted rate is 1 in 1000. The risk of infection is thought to increase if the vitreous gel is allowed to travel along the track created by mjection and out of the injection wound, which is a process known as vitreous wickmg. Other established risks include accelerated cataract formation and retinal detachment. Also, the loss of drugs m the way described above may result m uneconomical waste of very expensive drugs, and potentially more frequent procedures. Thus, it is desirable to reduce or prevent the reflux of materials injected into the eye.

The normal method of mtravitreal injection uses a standard 1 ml syringe to load a drug. Alternatively, a prefilled syringe is used m the case of some drugs. The injection procedure must be totally sterile and performed with a local anaesthetic applied to the injection site. Typically, a 27 or 30 gauge needle is inserted into the posterior chamber of the eye, into the vitreous cavity. A 25 gauge port is created m vitrectomy surgery. The location of the injection is at the pars plana, 3 mm behind the limbus m phakic eyes (eyes with their own lens) and 3.5 mm for those with an artificial lens. Thus, a tiny but full thickness wound is made running from the outside of the eye into the vitreous cavity and the vitreous gel. As can be easily appreciated, the drug can escape and reflux back through the wound created during the procedure. Furthermore, the denser and more viscid, or the greater the volume of the drug preparation, as m the case with Triamcinolone, the greater the reflux.

A prior tool that is used to prevent drug reflux is a "cellulose spear", which is a highly absorbent swab attached to one end of a stick-like handle. The cellulose spear is a generic tool that is designed for all types of ophthalmic surgical procedures and is mainly concerned with absorbing blood and fluid from the surface of the eye. For this reason, the cellulose spear is not suited for the prevention of reflux.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the pπor art, or to provide a useful alternative.

SUMMARY OF THE INVENTION

In a first aspect of the invention, there is provided a medical tool for minimising post injection liquid reflux from a needle entry point m an injection surface, the medical tool including: a resilient seal having a proximal side and a distal side, the resilient seal configured to allow a needle to extend from the proximal side to the distal side, the resilient seal being movable to move the distal side into contact with the injection surface; wherein the resilient seal resiliently deforms when the needle is removed from the distal side to seal the needle entry point, thereby minimising liquid flow from the needle entry point.

Preferably, the resilient seal is configured to allow a needle to extend through the seal from the proximal side to the distal side, and the resilient seal is movable to move the distal side into contact with the injection surface around the needle entry point. Preferably, the resilient seal includes two complementary seal portions, the complementary seal portions being resiliently deformable to releasably clamp the needle therebetween and seal against each other when the needle is removed.

Preferably, the complementary seal portions are also releasably lockable together to releasably clamp the needle therebetween. More preferably, the complementary seal portions are releasably snap-lockable together to releasably clamp the needle therebetween. The complementary seal portions are preferably hingedly interconnected.

In one preferred embodiment, the resilient seal includes two discrete complementary seal portions. In another preferred embodiment, the resilient seal includes a slit, thereby forming the two complementary seal portions.

In another embodiment, the resilient seal is configured for penetration of the needle therethrough to allow the needle to extend from the proximal side to the distal side. Preferably, the resilient seal is also resiliently deformable to releasably clamp the needle once the needle has penetrated therethrough. In a further embodiment, the resilient seal is movable into contact with the needle such that the resilient seal deforms around the needle, and the needle extends from the proximal side to the distal side. In a variation, the resilient seal is movable into contact with the needle such that the needle forms a slit in the resilient seal, thereby forming the two complementary seal portions. Preferably, the resilient seal is slidable along the needle into contact with the injection surface.

Preferably, the resilient seal is also configured to seal a gap between the side of the needle and the injection surface surrounding the needle entry point when the resilient seal is in contact with the injection surface, thereby minimising liquid flow from the needle entry point before the needle is removed from the distal side.

Preferably, the medical tool includes a handle connected to the resilient seal. In one preferred embodiment, the handle is a finger grip. In another preferred embodiment, the handle is elongate to facilitate handling spaced away from the resilient seal. The handle can be integral with the resilient seal. Preferably, the handle includes two handle members, each connected to a respective one of the complementary seal portions. The two handle members are preferably releasably lockable to each other to releasably clamp the needle between the complementary seal portions. More preferably, the handle members are releasably snap-lockable to each other to releasably clamp the needle between the complementary seal portions. The handle members can be hingedly interconnected. Each handle member can be integral with a respective one of the complementary seal portions. - A -

Preferably, the medical tool includes a housing that holds the resilient seal. The housing preferably includes housing portions each holding a respective one of the complementary seal portions. More preferably, the handle is connected to the housing. Each handle member is preferably connected to a respective one of the housing portions. The housing portions can be hmgedly interconnected. The handle and the housing can be integral. Alternatively or additionally, the housing can be integral with the resilient seal.

Preferably, the medical tool includes a collar to facilitate locating of the needle relative to the resilient seal. The collar is preferably configured to engage a syringe to which the needle is attached. Preferably, the collar is resiliently deformable to accommodate syringes of various sizes. In one embodiment, the collar is located on, and can be integrally formed with, the resilient seal. In another embodiment, the collar is located on, and can be integrally formed with, the housing. In a further embodiment, the collar is located on, and can be integrally formed with, the handle.

Preferably, the medical tool includes interlocking portions to facilitate and maintain correct alignment of the complementary seal portions. In one embodiment, the interlocking portions are each located on, and can be integrally formed with, a respective one of the complementary seal portions. In another embodiment, the interlocking portions are each located on, and can be integrally formed with, a respective one of the housing portions. In a further embodiment, the interlocking portions are each located on, and can be integrally formed with, a respective one of the handle members.

Preferably, the handle is made from rigid plastics material. Preferably, the housing is made from rigid plastics material. More preferably, the handle and the housing are integrally molded from rigid plastics material. Preferably, the resilient seal is made from resiliently deformable plastics material. More preferably, the resilient seal is made from rubber or rubber- like material.

Preferably, the injection surface is a surface of an eye. Preferably, the medical tool is used m mtravitreal injections procedures, in which case, the injection surface is generally the outer scleral surface. Preferably, the medical tool also minimises gas flow from the needle entry point, the medical tool thereby also being for minimising post injection gas reflux from the needle entry point.

In a second aspect of the invention, there is provided a method of minimising post injection liquid reflux from a needle entry point m an injection surface, the method including the steps of: providing a resilient seal having a proximal side and a distal side; configuring the resilient seal such that a needle extends from the proximal side to the distal side; moving the resilient seal to move the distal side into contact with the injection surface; removing the needle from the distal side, whereby the resilient seal resiliently deforms to seal the needle entry point, thereby minimising liquid flow from the needle entry point; and maintaining pressure on the resilient seal to continue sealing the needle entry point for a predetermined period of time.

Preferably, the resilient seal is configured to allow a needle to extend through the seal from the proximal side to the distal side, and the resilient seal is movable to move the distal side into contact with the injection surface around the needle entry point.

Preferably, the resilient seal provided is the resilient seal of the first aspect of the invention described above. More preferably, the method includes the step of providing the medical tool of the first aspect of the invention described above, the resilient seal being the resilient seal of the medical tool.

Preferably, the method includes the step of piercing the needle through the injection surface before moving the resilient seal to move the distal side into contact with the injection surface. In one preferred embodiment, the step of piercing the needle through the injection surface occurs before configuring the resilient seal such that the needle extends from the proximal side to the distal side. In another preferred embodiment, the step of piercing the needle occurs after configuring the resilient seal such that the needle extends from the proximal side to the distal side. Preferably, the step of configuring the resilient seal such that the needle extends from the proximal side to the distal side includes the step of releasably clamping the needle between the resiliently deformable complementary seal portions. Preferably, the needle is releasably clamped between the resiliently deformable complementary seal portions by releasably snap- locking the complementary seal portions together. In one preferred embodiment, the step of releasably clamping the needle includes the steps of moving the complementary seal portions apart, positioning the needle between the complementary seal portions, and moving the complementary seal portions together. In embodiments where the medical tool includes two handle members, the steps of moving the complementary seal portions apart, positioning the needle between the complementary seal portions, and moving the complementary seal portions together, are facilitated by using the two handle members. Preferably, the method includes the step of releasably locking the two handle members to each other to releasably clamp the needle between the complementary seal portions. More preferably, the handle members are releasably snap-locked to each other to releasably clamp the needle between the complementary seal portions. In embodiments where the resilient seal includes a slit, the step of releasably clamping the needle includes the step of sliding the needle into the slit. In another embodiment, the step of configuring the resilient seal such that a needle extends from the proximal side to the distal side, includes the step of piercing the needle through the resilient seal. Preferably, the step of piercing the needle through the resilient seal includes releasably clamping the needle with the resilient seal. In embodiments where the medical tool includes a collar, the step of configuring the resilient seal such that the needle extends from the proximal side to the distal side, includes the step of locating the needle relative to the resilient seal with the collar. Preferably, the step of locating the needle includes engaging the collar with a syringe to which the needle is attached.

In embodiments where the medical tool includes interlocking portions, the step of configuring the resilient seal such that the needle extends from the proximal side to the distal side, includes the step of bringing the interlocking portions into interlocking engagement with each other to facilitate and maintain correct alignment of the complementary seal portions.

In one preferred embodiment, the step of moving the resilient seal to move the distal side into contact with the injection surface includes the step of sliding the resilient seal along the needle into contact with the injection surface. In another preferred embodiment, the step of piercing the needle through the injection surface includes the step of inserting the needle until the resilient seal is moved into contact with the injection surface, thereby moving the distal side into contact with the injection surface.

Preferably, the step of moving the resilient seal into contact with the injection surface includes the step of sealing a gap between the side of the needle and the injection surface surrounding the needle entry point once the resilient seal is in contact with the injection surface, thereby minimising liquid flow from the needle entry point before the needle is removed from the distal side.

Preferably, the method includes the step of injecting an injectable material through the injection surface into a target body after the step of moving the resilient seal into contact with the injection surface.

Preferably, the step of removing the needle from the distal side includes withdrawing the needle from the distal side towards the proximal side. More preferably, the step of withdrawing the needle from the distal side towards the proximal side includes withdrawing the needle from the proximal side, thereby withdrawing the needle from the resilient seal.

Preferably, the step of maintaining pressure on the resilient seal includes maintaining finger pressure on the resilient seal. In embodiments where the medical tool includes a handle, the handle is preferably used to maintain finger pressure. Preferably, pressure is maintained for a predetermined period of time sufficient to allow the absorption of the injectable material by the target body. Preferably, the injection surface of the method is a surface of an eye, and the target body is the eye. Preferably, the method is used m intravitreal injection procedures. Preferably, the method also minimises gas flow from the needle entry point, the method thereby also being for minimising post injection gas reflux from the needle entry point. Preferably, the injectable material includes a liquid. The injectable material can also include a gas.

In a third aspect of the invention, there is provided a medical tool for minimising post injection liquid reflux from a needle entry point in an injection surface, the medical tool including: a seal substantially impervious to liquid, and movable into contact with the injection surface to seal the needle entry point, thereby minimising liquid flow from the needle entry point.

Preferably, the seal is also substantially impervious to gas, thereby minimising gas flow from the needle entry point.

Preferably, the seal is resiliently deformable such that the seal resiliently deforms when moved into contact with the injection surface, thereby applying sealing pressure to the injection surface to improve sealing of the needle entry point.

Preferably, the medical tool includes a handle connected to the seal to facilitate handling of the seal.

In a fourth aspect of the invention, there is provided a method of minimising post injection liquid reflux from a needle entry point in an injection surface, the method including the steps of: providing a seal substantially impervious to liquid; moving the seal into contact with the injection surface to seal the needle entry point shortly after a needle is removed from the needle entry point, thereby minimising liquid flow from the needle entry point; and maintaining pressure on the resilient seal to continue sealing the needle entry point for a predetermined period of time.

Preferably, the seal provided is the seal of the third aspect of the invention described above. More preferably, the method includes the step of providing the medical tool of the third aspect of the invention described above, the seal being the seal of the medical tool. Preferably, the step of moving the seal into contact with the injection surface includes deforming the seal against the injection surface, thereby applying sealing pressure to the injection surface to improve sealing of the needle entry point.

The invention advantageously minimises drug reflux, and generally minimises gas and liquid reflux, from a needle entry point, both during and post injection. In particular, the invention advantageously seals an injection wound, thereby minimising or preventing the escape of injected fluids or fluids from tissue under the injection surface through the wound track to the outside. This assists in guaranteeing the accurate delivery of a specific quantity of a prescribed drug into the target body. Thus, drug loss is limited, thereby resulting in cost savings, especially in the case of expensive drugs. The accurate delivery of a drug also limits the number of injections a patient may have to undergo to obtain the maximal benefit of the injections. This is especially advantageous in the case of mtravitreal injections in view of the inconvenience and possible complications noted above. Also in the case of intravitreal injection procedures, the invention reduces vitreous wicking through the scleral wound, thereby reducing the risk of developing endophthalmitis. Another ocular surgical procedure for which the invention is well suited is vitrectomy. The invention also reduces the number of staff required during injection procedures. For example, the embodiment having a finger gπp is especially suited for use by the surgeon performing the injection at the time of injecting.

BRIEF DESCRIPTION OF THE FIGURES

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures, m which:

Figure 1 is a series of five perspective views showing a first embodiment tool for minimising post injection reflux according to the invention illustrated in use in a vitreal injection procedure;

Figure 2 is an enlarged perspective view of the first embodiment tool in Figure 1 shown m the opened position;

Figure 3 is an enlarged perspective view of the first embodiment tool m Figure 1 shown in the closed position;

Figure 4 is a series of five perspective views showing a second embodiment tool for minimising post injection reflux according to the invention illustrated in use in a vitreal injection procedure;

Figure 5 is an enlarged perspective view of the of the second embodiment tool in Figure 4 shown in the opened position;

Figure 6 is an enlarged perspective view of the second embodiment tool in Figure 4 shown in the closed position; Figure 7 is a perspective view of the third embodiment tool according to the invention shown in the opened position;

Figure 8 is a perspective view of a fourth embodiment tool according to the invention; Figure 9 is a perspective view of a fifth embodiment tool according to the invention; Figure 10 is a perspective view of a sixth embodiment tool according to the invention; Figure 11 is a perspective view of a seventh embodiment tool according to the invention; Figure 12 is a perspective view of an eighth embodiment tool according to the invention; and

Figure 13 is a perspective view of a ninth embodiment tool according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring to the Figures, in which equivalent features in different embodiments of the invention have the same reference numerals, all of the embodiments of the medical tool shown are for minimising post injection liquid reflux from a needle entry point 2 in an injection surface 3. Each embodiment of the medical tool shown in the Figures includes a resilient seal 4 having a proximal side 5 and a distal side 6. The resilient seal 4 is configured to allow a needle 7 to extend through the seal from the proximal side 5 to the distal side 6, and the resilient seal 4 is also movable to move the distal side 6 into contact with the injection surface 3. The resilient seal 4 resiliently deforms when the needle 7 is removed from the distal side 6 to seal the needle entry point 2, thereby minimising liquid flow from this opening. The resilient seal 4 is slidable along the needle 7 into contact with the injection surface 3.

The resilient seal 4 is also configured to seal a region between the needle 7 and the needle entry point 2 when the resilient seal is in contact with the injection surface 3, thereby minimising liquid flow from the needle entry point 2 before the needle 7 is removed from the distal side.

The present embodiments are designed primarily for use in intravitreal injection procedures, where the injection surface 3 is a surface of the eye, particularly, the scleral surface. The precise anatomical location of the needle entry point 2 is the pars plana, which is located 3 mm behind the limbus in phakic eyes (eyes with their own lens) and 3.5 mm for those with an artificial lens. The present embodiments also minimise gas flow from the needle entry point 2, both during and post injection. However, the invention, including the medical tool of the invention, can also be used for other portions of a human or animal body, or any other body where liquid or gas reflux can occur during or post injection. For example, other uses or adaptations of the invention include minimising or preventing reflux, blood, or fluid loss during and after intravenous injection of drugs or fluids, and the injection of drugs into the spinal fluid during procedures such as lumbar puncture.

In each embodiment shown in Figures 1 to 11 and 13, the resilient seal 4 includes two complementary seal portions 8 and 9, which are resiliently deformable to releasably clamp the needle 7 therebetween. As shown in the figures, the complementary seal portions 8 and 9 are preferably two discrete but potentially interlinked portions. Each embodiment in Figures 1 to 9 and 12 and 13 further includes a handle 10 connected to the resilient seal 4. The handle 10 can be integral with the resilient seal 4, and can also be mtegrally formed with the resilient seal 4. The handle may include two handle members 11 and 12, each connected to a respective one of the complementary seal portions 8 and 9. Each handle member 11 and 12 can be integral with a respective one of the complementary seal portions 8 and 9, and can be integrally formed with a respective one of the complementary seal portions 8 and 9.

The embodiment of Figures 1 to 6 and 12 and 13 also include a housing 13 that holds the resilient seal 4. In these embodiments housing 13 includes two housing portions 14 and 15, each holding a respective one of the complementary seal portions 8 and 9. The handle 10 is connected to the housing 13, with each handle member 11 and 12 connected to a respective one of the housing portions 14 and 15. In these present embodiments, the handle 10 is integrally formed with the housing 13, with each handle member Hand 12 integrally formed with the respective housing portion 14 and 15. The handle 10 and the housing are preferably formed from polypropylene. The resilient seal is preferably made from soft rubber or rubber-like material. In other embodiments, however, the housing 13 can be integral, or integrally formed with the resilient seal 4. In further embodiments, such as that shown m Figure 7, the handle 10, the housing 13, and the resilient seal 4 can all be integral, or integrally formed. The handle 10, the housing 13, and the resilient seal 4 can each be made from any suitable material, including but not limited to, other rigid or deformable plastics materials. The embodiments shown in Figures 1 to 6 and 12 also include a collar 17 to facilitate locating of the needle 7 relative to the resilient seal 4. The collar 17 is configured to engage a syringe 18 to which the needle 7 is attached, thereby locating the needle 7 in a position relative to the resilient seal 4.

In the first embodiment, as shown in Figures 1 to 3, the handle 10 is a finger grip. The finger grip is circular in cross-section and is connected to the resilient seal 4. The finger grip includes a short strut 19 that is connected to the housing 13, which m turn, holds the resilient seal. The finger grip is split across a circular cross-section to define the handle members 11 and 12. The housing portions 14 and 15 are hmgedly interconnected. Thus, the complementary seal portions 8 and 9 are also hmgedly interconnected, as are the handle members 11 and 12. The collar 17 is integrally formed with the resilient seal 4, and is located at an end of the housing 13 opposite to the resilient seal 4. The collar 17 is resiliently deformable to accommodate syringes of various sizes. In this case, the collar 17 is made from rubber or rubber-like material, since it is integrally formed with the resilient seal 4. In this particular embodiment, the finger gπp also includes raised portions in the form of a plurality of squat cylindrical protrusions 20, m order to facilitate gripping. However, the raised portions 20 can take many other configurations m further embodiments. The two handle members 11 and 12 are releasably lockable to each other to releasably clamp the needle 7 between the complementary seal portions 8 and 9. In the present preferred embodiment, the handle members 11 and 12 are releasably snap-lockable to each other to releasably clamp the needle 7 between the complementary seal portions 8 and 9. Thus, the complementary seal portions 8 and 9 are releasably lockable, and m particular releasably snap- lockable, together to releasably clamp the needle 7 therebetween, since the handle members 11 and 12 are releasably snap-lockable to each other. In other embodiments, however, the complementary seal portions 8 and 9 can be directly releasably lockable or snap-lockable together. One handle member 12 includes a first annular flange 21 having a radially outwardly protruding, circumferentially extending lip 22. The other handle member 11 includes a second annular flange 23 complementary to and mutually opposable to annular flange 21. The second annular flange 23 includes a radially inwardly protruding, circumferentially extending lip 24. One or both of the lips 22 and 24 resiliently deform to releasably snap-lock together when the handle members 11 and 12 are brought together, thereby releasably snap-locking the handle members to each other.

In the second embodiment, as shown in Figures 4 to 6, the handle 10 is elongate to facilitate handling spaced away from the resilient seal 4. The handle 10 has two elongate handle members 11 and 12, which are hingedly interconnected distal to the housing portions 14 and 15. Thus, the complementary seal portions 8 and 9 are also hingedly interconnected, as are the housing portions 14 and 15. The collar 17 is integrally formed with the housing 13, and is located at an end of the housing opposite the resilient seal 4. In other embodiments, the collar is located on, and can be integrally formed with, the handle 10, or the resilient seal 4.

The present embodiment also includes interlocking portions 26 to facilitate and maintain correct alignment of the complementary seal portions. One of the interlocking portions, in the form of a protruding stub 27, is located on the upper half of one of the housing portions 14. The stub is mutually opposable with a complementary cut-out 28, defining another interlocking portion, located on the upper half of the other housing portion 15. Another similar protruding stub 29 is located on the upper half of the housing portion 15, and is mutually opposable with a complementary cut-out 30 located on the upper half of the housing portion 14. The stub 29 is diagonally opposite the other stub 27. Thus, the interlocking portions 26 restrict relative movement of the complementary seal portions 8 and 9 along the needle 7. Both stubs 27 and 29 and both cut-outs 28 and 30 are integrally formed with the respective housing portions 14 and 15. Figure 7 is a perspective view of a third embodiment tool, which is a modification of the first embodiment shown in Figures 1 to 3. In this version, the entire device is made from a smgle piece of suitable rubber like material that folds around the needle 7. The resilient seal 4 has two resiliently deformable complimentary seal portions 8 and 9, which are connected via an integrally formed hinge 35. The handle 10 similarly comprises two handle members 11 and 12, which are integrally formed with the sealed portions 8 and 9. In use, the seal portions 8 and 9 can be retained in sealing engagement around the needle 7 by means of the operator simply holding the two handle portions 11 and 12 together. Alternatively, some form of clip means may be provided to retain the tool once it has been folded around the needle.

Turning next to Figure 8, there is shown a fourth embodiment tool according to the invention. In this particular arrangement, the seal 4 is made from a single piece of suitable rubber like material and a slit 36 extends part way into the seal to accommodate the needle 7, thereby forming two engaging seal portions 8 and 9. A single handle 10 is provided which is of sufficient stiffness such that pressure can be applied to the seal 4 against the underlying injection surface. This particular embodiment can be varied to provide an identical structure but without the preformed slit 36. With such an embodiment, the seal is simply applied over the needle entry point 2 immediately after removal of the needle 7.

Figure 9 illustrates a fifth embodiment tool according to the invention which is similar m many ways to the second embodiment shown m Figures 4 to 6. However, in this particular case the seal 4 is not captively retained within a housing from which the handle 10 extends. Instead, the seal 4 comprises linked seal portions 8 and 9 which are hmgedly connected to fold around the needle 7. The seal 4 includes an undercut portion 37 which is adapted to receive callipers 38 formed as part of the handle arrangement 10. These callipers 38 engage around the seal 4 to retain it against the needle and facilitate sliding movement of the seal 4 along the length of the needle as required. In the embodiment illustrated, there is shown a tweezer like handle arrangement whereby a closing pressure is applied by the operator squeezing the two arms of the handle 10 together. However, m other variations there could be a snap fit system to hold them together, or an alternative structure could be provided which is normally biased into the closed position such that pressure is applied to open the callipers and they re-clamp automatically when the handle is released. In a further variation, the seal 4 is captively retained between the callipers 38 first. The callipers are then brought together to fold and clamp the seal 4 around the needle 7. The seal 4 m this embodiment and its variations can be disposable. The embodiment allows the use of more robust stainless steel tweezers.

Turning next to Figure 10 there is shown a perspective view of a sixth embodiment tool according to the invention. This is an automated device which has an integral syringe. When activated, the device automatically clamps the sealed portions 8 and 9 around the needle 7. The device then automatically slides slowly down the needle and applies pressure to the injection surface. Once the

has made contact with the injection surface, it continues applying pressure while the needle is automatically retracted.

Figure 11 shows a seventh embodiment tool according to the invention which is m the form of a simple seal 4 having mating parts 8 and 9 which can be clamped around the needle 7. The seal 4 includes a necked finger grip portion 39 which facilitates sliding of the seal along the needle and also helps to apply pressure directly over the needle entry point 2 m the injection surface. The two parts of the seal 4 can be retained using any suitable form of clip means.

Referring next to Figure 12 there is shown an eighth embodiment tool according to the invention. This particular embodiment is visually very similar to the first embodiment shown m Figures 1 to 3. However, m this case the seal 4 is captive withm the fixed unitary housing 13. In this manner, the needle 7 is pierced through the rubber like seal 4 prior to the procedure. The handle is not m two parts as m the first embodiment. The seal 4 can be a single continuous membrane or could have some form of pre-formed slit to assist piercing by the needle.

Finally, Figure 13 shows a ninth embodiment tool according to the invention. This is very similar to the first embodiment of Figures 1 to 3 m that it has a two-part hmged structure which clamps together with a finger grip handle 10. However, this version does not include the collar

17 of the first embodiment for clamping to the syringe 18 and instead is configured to clamp only on to the needle 7.

In another aspect, the invention also provides a method of minimising post injection liquid reflux from a needle entry point 2 m an injection surface 3. Preferred embodiments of the method include the steps of: providing a resilient seal 4 having a proximal side 5 and the distal side 6; configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6; moving the resilient seal 4 to move the distal side 6 into contact with the injection surface

3; removing the needle 7 from the distal side 6, whereby the resilient seal resiliently deforms to seal the needle entry point 2, thereby minimising liquid flow from the needle entry point 2; and maintaining pressure on the resilient seal 4 to continue sealing the needle entry point 2 for a predetermined period of time.

Thus, the embodiments include the step of providing the medical tool described above, thereby providing the resilient seal 4. The present embodiments are therefore used m mtravitreal injection procedures, where the injection surface 3 is a surface of the eye, particularly, the pars plana, which is located 3 mm behind the limbus in phakic eyes (eyes with their own lens) and

3.5 mm for those with an artificial lens. The present embodiments also minimises gas flow from the needle entry point 2, both during and post injection. However, the invention, including the method of the invention, can also be used for other portions of a human or animal body, or any other body where liquid or gas reflux can occur during or post injection.

The method includes the step of piercing the needle 7 through the injection surface 3 before moving the resilient seal 4 to move the distal side 6 into contact with the injection surface 3. Referring to the embodiment shown in Figures 4 to 6, the step of piercing the needle 7 through the injection surface 3 occurs before configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6. Referring to the embodiment shown m Figures 1 to 3, the step of piercing the needle 7 occurs after configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6.

Referring to each of the embodiments shown in Figures 1 to 11 and 13, the step of configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6 includes the step of releasably clamping the needle 7 between the resiliently deformable complementary seal portions 8 and 9. Referring to the embodiment of Figures 1 to 3 and 13, the needle 7 is releasably clamped between the resiliently deformable complementary seal portions 8 and 9 by releasably snap-locking the complementary seal portions together.

Referring to each embodiment of Figures 1 to 7, 9, 11 and 13, the step of releasably clamping the needle 7 includes the steps of moving the complementary seal portions 8 and 9 apart, positioning the needle 7 between the complementary seal portions 8 and 9, and moving the complementary seal portions together. Referring to the embodiments of Figures 1 to 7, 9 and 13, the steps of moving the complementary seal portions apart, positioning the needle between the complementary seal portions, and moving the complementary seal portions together, are facilitated by using the two handle members 11 and 12. Referring to the embodiments of Figures 1 to 3 and 13, the method includes the step of releasably locking the two handle members 11 and 12 to each other to releasably clamp the needle 7 between the complementary seal portions 8 and 9. More particularly, the handle members 11 and 12 are releasably snap- locked to each other to releasably clamp the needle 7 between the complementary seal portions 8 and 9.

Referring to each embodiment of Figures 1 to 6 and 12, the step of configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6, includes the step of locating the needle 7 relative to the resilient seal 4 with the collar 17. The step of locating the needle 7 includes engaging the collar 17 with a syringe 18 to which the needle is attached.

Referring to the embodiment shown in Figures 4 to 6, the step of configuring the resilient seal 4 such that the needle 7 extends from the proximal side 5 to the distal side 6, includes the step of bringing the interlocking portions 26 into interlocking engagement with each other to facilitate and maintain correct alignment of the complementary seal portions 8 and 9.

In most embodiments, the step of moving the resilient seal 4 to move the distal side 6 into contact with the injection surface 3 includes the step of sliding the resilient seal 4 along the needle 7 into contact with the injection surface 3. In other embodiments, the step of piercing the needle 7 through the injection surface 3 includes the step of inserting the needle 7 until the resilient seal 4 is moved into contact with the injection surface 3, thereby moving the distal side 6 into contact with the injection surface 3.

Referring to each embodiment shown, the step of moving the resilient seal 4 into contact with the injection surface 3 includes the step of sealing a gap between the side of the needle 7 and the injection surface surrounding the needle entry point 2. This minimises liquid and gas flow from the needle entry point 2 before the needle 7 is removed from the distal side 6.

Referring to each embodiment of the Figures, the method includes the step of injecting an injectable material through the injection surface 3 into a target body after the step of moving the resilient seal 4 into contact with the injection surface 3. In the present embodiments, the target body is a human eye. However, as noted above, the target body can be other portions of a human or animal body, or any other body where liquid or gas reflux can occur during or post injection.

Referring again to each embodiment of the Figures, the injectable material can be a liquid. Additionally, or alternatively, the injectable material can be a gas. The step of removing the needle 7 from the distal side 6 includes withdrawing the needle from the distal side towards the proximal side 5. More particularly, the step of withdrawing the needle 7 from the distal side 6 towards the proximal side 5 includes withdrawing the needle from the proximal side, thereby withdrawing the needle completely from the resilient seal 4. The step of maintaining pressure on the resilient seal 4 includes maintaining finger pressure on the resilient seal 4 directly or by using the handle 10. Pressure is maintained for a predetermined period of time sufficient to allow the absorption of the injectable material by the target body.

Examples of drugs and pharmaceutical agents suitable for injection with the invention include, without limitation: air purified water, saline, pharmaceutical agents in suspension with non-active excipients such as hyluronidases or collagenases to enhance function/solubility/stability, antibiotics, antivirals, and antifungals; antiallergenic agents and mast cell stabilizers; steroidal and non-steroidal anti-inflammatory agents; cyclooxygenase inhibitors, including, without limitation, Cox I and Cox II inhibitors; combinations of anti- mfective and anti-inflammatory agents; monoclonal antibodies directed against cytokines, including, without limitation, anti tumor necrosis factor, ILl ; anti-glaucoma agents, including, without limitation, adrenergics, β-adrenergic blocking agents, a-adrenergic agonists, parasypathomimetic agents, cholmesterase inhibitors, carbonic anhydrase inhibitors, and prostaglandins; combinations of anti-glaucoma agents; antioxidants; nutritional supplements; drugs for the treatment of cystoid macular edema including, without limitation, non-steroidal anti-inflammatory agents; drugs for the treatment of ARMD, including, without limitation, angiogenesis inhibitors and nutritional supplements; drugs for the treatment of herpetic infections and CMV ocular infections; drugs for the treatment of proliferative vitreoretmopathy, including, without limitation, antimetabolites and fibrinolytics; wound modulating agents, including, without limitation, growth factors; antimetabolites; neuroprotective drugs, including, without limitation, eliprodil; and angiostatic steroids for the treatment of diseases or conditions of posterior segment 26, including, without limitation, ARMD, CNV, retinopathies, retinitis, uveitis, macular edema, and glaucoma.

Although the invention has been described with reference to specific examples, it will be appreciated by those skilled m the art that the invention may be embodied in many other forms. It will also be appreciated by those skilled m the art that the features of the various examples described may be combined m many other combinations.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. A medical tool for minimising post injection liquid reflux from a needle entry point in an injection surface, the medical tool including: a resilient seal having a proximal side and a distal side, the resilient seal configured to allow a needle to extend from the proximal side to the distal side, the resilient seal being movable to move the distal side into contact with the injection surface; wherein the resilient seal resiliently deforms when the needle is removed from the distal side to seal the needle entry point, thereby minimising liquid flow from the needle entry point.

2. A medical tool according to claim 1. wherein the resilient seal is configured to allow a needle to extend through the seal from the proximal side to the distal side, and the resilient seal is slidablc along the needle to move the distal side into contact with the injection surface around the needle entry point.

3. A medical tool according to claim 1 or claim 2, wherein the resilient seal includes two complementary seal portions, the complementary seal portions being resiliently deformable to releasably clamp the needle therebetween and seal against each other when the needle is removed.

4. A medical tool according to claim 3. including a handle having two handle members hingedϊy interconnected, each connected to a respective one of the complementary seal portions.

5. A medical tool according to claim 4, wherein the two handle members are releasably lockable to each other to releasably clamp the needle between the complementary seal portions.

6. A medical tool according to claim 5, including a housing having two housing portions each holding a respective one of the complementary seal portions, each handle member being connected to a respective one of the housing portions.

7. A medical tool according to claim 6, including a collar to facilitate locating of the needle relative to the resilient seal by engaging a syringe to which the needle is attached, the collar being located on and integrally formed with one of the resilient seal, the housing, and the handle.

8. A medical tool according to claim 7, including interlocking portions to facilitate and maintain correct alignment of the complementary seal portions, the interlocking portions being located on and integrally formed with one of the resilient seal, the housing, and the handle.

9. A medical tool according to claim 8, wherein the handle and the housing are integrally molded from rigid plastics material, and the resilient seal is made from resiliently deformable plastics material substantially impervious to liquid.

10. A method of minimising post injection liquid reflux from a needle entry point in an injection surface, the method including the steps of: providing a resilient seal having a proximal side and a distal side; configuring the resilient seal such that a needle extends from the proximal side to the distal side; moving the resilient seal to move the distal side into contact with the injection surface; removing the needle from the distal side, whereby the resilient seal resiliently deforms to' seal the needle entry point, thereby minimising liquid flow from the needle entry point; and maintaining pressure on the resilient seal to continue sealing the needle entry point for a predetermined period of time.

1 1. A method according to claim 10, including the step of piercing the needle through the injection surface before the step of moving the resilient seal to move the distal side into contact with the injection surface, wherein the resilient seal is moved by sliding the resilient seal along the needle.

12. A method according to claim 10, including the step of piercing the needle through the injection surface and inserting the needle until the resilient seal is moved into contact with the injection surface, thereby moving the distal side into contact with the injection surface.

13. A method according to any one of claims 10 to 12, including the step of injecting an injectable material through the injection surface into a target body after the step of moving the resilient seal into contact with the injection surface.

14. A method according to any one of claims 10 to 13, including the step of providing the medical tool defined in claim 9.

15. A method according to claim 14, wherein the step of configuring the resilient seal such that the needle extends from the proximal side to the distal side includes the step of releasably clamping the needle between the resiliently deformable complementary seal portions.

\6. A method according to claim 15, including the step of releasably locking the two handle members to each other to releasably clamp the needle between the complementary seal portions.

17. A method according to any one of claims 14 to 16, wherein the step of configuring the resilient seal such that the needle extends from the proximal side to die distal side, includes the step of locating the needle relative to the resilient seal by engaging the collar with a syringe to which the needle is attached.

18. A method according to any one of claims 14 to 17, wherein the step of configuring the resilient seal such that the needle extends from the proximal side to the distal side, includes the step of bringing the interlocking portions into interlocking engagement with each other to facilitate and maintain correct alignment of the complementary seal portions.

19. A medical tool for minimising post injection liquid reflux from a needle entry point in an injection surface, the medical tool including: a seal substantially impervious to liquid, and movable into contact with the injection surface to seal the needle entry point, thereby minimising liquid flow from the needle entry point. .

20. A method of minimising post injection liquid reflux from a needle entry point in an injection surface, the method including the steps of: providing a seal substantially impervious to liquid; moving the seal into contact with the injection surface to seal the needle entry point shortly after a needle is removed from the needle entry point, thereby minimising liquid flow from the needle entry point; and maintaining pressure on the resilient seal to continue sealing the needle entry point for a predetermined period of time.