Abstract:
In a method for sclerotherapy for treating varicose veins, a flushing solution, such as sterile saline solution, is initially injected into the vein or vessel being treated. The flushing solution displaces or flushes out blood from the treatment site of the vessel. A sclerosing agent is then injected into the treatment site. The displacement of blood before introduction of the sclerosing agent reduces complications. A syringe assembly useful for performing the method has first and second reservoirs sealed off from each by an end cap. The end cap is removed just before use. A needle is attached and is connected to both reservoirs. Flushing solution is delivered from the first reservoir followed by sclerosing solution delivered from the second reservoir, without removing the needle from the vessel.

Description:
FIELD OF THE INVENTION  
         [0001]    The field of the invention is sclerotherapy. More specifically, the invention relates to the treatment of spider and varicose veins via sclerotherapy. The invention further relates to a novel syringe assembly useful in sclerotherapy, as well as in other medical applications.  
         BACKGROUND OF THE INVENTION  
         [0002]    Spider veins or telangiectasias of the legs are common conditions, especially among women. With this condition, small dark-colored veins form on the legs, just underneath the skin surface. These types of veins can form anywhere on the legs between the thigh and ankle. They often have a web or sunburst pattern, but may also be formed as short, somewhat random line segments. In many cases, spider veins are largely unnoticeable, when localized in a small area. However, when larger areas of skin are affected, spider veins can be perceived as having a detrimental appearance on the skin.  
           [0003]    Varicose veins are larger veins, in comparison to spider veins. Varicose veins may protrude or be raised above the skin surface. They typically have a blue or purple color. A varicose vein generally contains stagnant or refluxing blood, which is out of circulation. Consequently, a varicose vein no longer functions to channel blood flow back to the circulatory system or the heart. Larger veins have valves which maintain blood flow in the forward direction. If the valves fail, blood accumulates under pressure, causing the veins of the leg to engorge. These varicose veins often appear as bulging, and have a rope-like or thread-like appearance. In more severe cases, these vascular disorders can result in aching, throbbing, swelling, or other conditions requiring medical treatment. Moreover, many patients having varicose veins, even without these symptoms, become distressed by the appearance of the varicose veins. Consequently, various treatments have been developed for both medical and cosmetic reasons. These treatments include surgery for severe cases, as well as sclerotherapy, typically used for smaller varicose veins closer to the skin surface. In the past, sclerotherapy has been performed by injecting a sclerosing agent into the vein. This non-surgical procedure destroys the varicose vein by irritating the vein wall, and causing the vein to close up. Procedures using ultrasound, or an electrosurgical electrode in combination with sclerotherapy have also been proposed. In general, sclerotherapy is a proven, safe, and effective technique.  
           [0004]    Notwithstanding the successes of sclerotherapy, complications can occur with these treatments. One such complication is ulceration. This complication results when a sclerosing solution is inadvertently injected intra-dermally or into surrounding tissue, rather than into the intended injection site in a vein. The sclerosing solution delivered outside of the vein can cause ulceration of the skin and surrounding tissue. As it may be difficult to consistently position the needle into the vein, this type of ulceration is a common complication. Hyperpigmentation is another complication. This complication results due to leakage of a blood component, hemosiderin pigment, from the damaged blood vessel or vein. Another complication is mat-like telangiectasia, which is the appearance of new, small blood vessels. Mat-like telangiectasia is believed to result from injection of an excessive amount of sclerosing solution.  
           [0005]    Accordingly, it is an object of the invention to provide improved methods and devices for treating spider and varicose veins via sclerotherapy.  
           [0006]    In certain medical procedures, it is advantageous to be able to inject different solutions into a single injection site, either simultaneously, or sequentially. Currently, this generally may require two separate injections. As a result, the two injections may not be located at the same location. In addition, two separate injections requires more time to provide, consumes more syringes and needles (generating more medical waste), and causes more pain and risk of infection to the patient.  
           [0007]    Accordingly, it is also an object of the invention to provide a novel syringe assembly useful for injecting two separate solutions in a single procedure.  
         SUMMARY OF THE INVENTION  
         [0008]    To these ends, in a first aspect, a method for treating a spider vein or a varicose vein via sclerotherapy includes injecting a flushing solution into the vein, to flush out blood from the section of the vein treated. A sclerosing solution is then injected into the blood vessel. The flushing solution and sclerosing solution are preferably injected from a single hypodermic needle. This allows both the flushing and sclerosing solutions to be injected sequentially at the same location and via a single injection or piercing of the skin and vein.  
           [0009]    In a second aspect of the invention, a syringe assembly for providing sclerotherapy has two separate reservoirs, chambers, or syringes. The first reservoir contains a flushing solution, preferably sterile saline solution. The second reservoir contains a sclerosing agent. A needle is attached at one end of the syringe assembly. Both reservoirs are connectable into the preferably 30-gauge needle. Each reservoir has a separate plunger.  
           [0010]    In use, in a third aspect of the invention, the needle is positioned in the vein or vessel to be treated. The plunger in the first reservoir is pressed, injecting the flushing solution into the vessel. Blood is flushed or displaced from the injection site. The second plunger is then pressed to inject the sclerosing agent into the vessel. By flushing the blood from the vessel, prior to injecting the sclerosing solution, the potential for blood leakage is greatly reduced. In addition, flushing the vessel with saline reduces the need to inject excessive amounts of sclerosing solution, thereby minimizing the potential of the mat-like telangiectasia complication.  
           [0011]    In a fourth aspect of the invention, the potential for inadvertently causing skin ulcerations by injecting a sclerosing solution at an improper location is reduced or eliminated. A sterile saline or other flushing solution is injected first into the injection site. The physician visually observes the injection site. If the vein disappears or tends to fade from view, the needle is properly positioned in the vein, and has flushed out the blood. The sclerosing solution is then injected into the same site via the same needle, without withdrawing the needle from the site. On the other hand, if the vein appearance remains largely unchanged after the flushing solution is injected, the physician then has a visual indication that the needle is not properly positioned in the vein. The needle is then withdrawn and relocated, and the visual observation procedure is repeated. This method avoids inadvertent injection of sclerosing solution into tissue outside of the vein, and the potential complications, such as skin ulcerations, which may accompany such events.  
           [0012]    In a fifth and separate aspect, a novel syringe assembly has two separate reservoirs connecting to a single needle. The liquid contents of the two reservoirs are separated from each during storage. Consequently, the syringe can be advantageously pre-filled with two different injectant solutions, and then optionally sealed in a package until use. The liquid contents are contained or sealed within the reservoirs by a plunger seal on a plunger towards the back end of the syringe assembly, and by an end cap or closed off needle at the front end. In use, an end cap is removed from the syringe assembly and a needle is attached, with the bore of the needle connecting into both reservoirs. Alternatively, a needle may be attached to the syringe assembly during or after manufacture, and no end cap is used. A needle tip protector/seal may optionally be pushed on to the tip of the needle, to avoid piercing packaging and needle stick incidents, and to prevent leakage from the reservoirs. The syringe assembly provides for improved sclerotherapy procedures, and may also be used for other procedures as well.  
           [0013]    Other and further objects and advantages will appear. The invention resides as well in subcombinations of the methods and devices shown and described. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of a syringe assembly for use in sclerotherapy, with a needle attached to the syringe assembly.  
         [0015]    [0015]FIG. 2 is a section view taken along line  2 - 2  of FIG. 1.  
         [0016]    [0016]FIG. 3 is enlarged perspective view of the end section of an alternative syringe design.  
         [0017]    [0017]FIG. 4 is a perspective view of the syringe assembly of FIG. 1 with an end plug attached to the syringe assembly.  
         [0018]    [0018]FIG. 5 is an enlarged perspective view of the end tube and end cap shown in FIG. 4.  
         [0019]    [0019]FIG. 6 is an enlarged perspective view of the cap shown in FIGS. 4 and 5.  
         [0020]    [0020]FIG. 7 is a side view, in part section, of an end cap on the end tube.  
         [0021]    [0021]FIG. 8 is a schematic view of the needle shown in FIG. 1 or  2  inserted into a vessel or vein.  
         [0022]    [0022]FIG. 9 is an enlarged partial section view of an alternative syringe assembly similar to the syringe assembly shown in FIG. 7, and having an end tube divider plate extending from the reservoir outlets to the front end of the syringe assembly.  
         [0023]    [0023]FIG. 10 is a perspective view of an alternative end cap for use with the syringe assembly shown in FIG. 9. 
     
    
     DETAILED DESCRIPTION  
       [0024]    The invention provides sclerotherapy methods having reduced risk of complications. The methods involve flushing or displacing blood from the vein or vessel, before injecting a sclerosing solution into the vessel. Injection of a clear flushing solution, such as sterile saline displaces blood from the vein. The vein can then be difficult or impossible for the physician to see. Consequently, injecting the sclerosing solution through the same needle, at the same injection site, avoids the need to find the vein, after the flushing solution is injected. Consequently, the methods are more advantageously performed using a syringe assembly which can deliver both solutions with a single injection, through a single needle. This reduces the number of injections required. In addition, it ensures that the flushing and sclerosing solutions are injected at the same location, while avoiding the difficulties of finding the vein after injection of the flushing solution.  
         [0025]    [0025]FIGS. 1 and 2 show a preferred syringe assembly for performing the methods described. As shown in FIG. 1, the syringe assembly  10  has a body  12 , preferably formed as a single molded plastic unit. The body  12  includes first and second barrels, chambers or reservoirs  14  and  16 . A first plunger  18  having a first end seal  22  is slidably positioned within the first reservoir  14 . Similarly, a second plunger  20  having a second end seal  24  is slidably positioned within the second reservoir  16 .  
         [0026]    The first plunger  18  has a first cap  26  and the second plunger  20  has a second cap  28 . The caps  26  and  28  are D-shaped, so that they can pass by each other. In use, the positions of the end caps  26  and  28  also provide a convenient visual and tactile indication of the relative volumes of fluids injected. For example, when they are aligned, the user knows that equal volumes have been injected. A hollow end tube  34  extends from the bottom or front end of the body  12 . A bore or opening  36  in the end tube  34  connects into the first reservoir  14  through a first outlet  30 . Similarly, the bore  36  in the end tube  34  also connects to the second reservoir  16  through a second outlet  32 . The outlets  30  and  32  connect the reservoirs  14  and  16  directly into the bore  36 . No valves or other flow control features are needed or used in this embodiment.  
         [0027]    A hypodermic needle  38  having a needle bore  40  is attachable to the end tube  34  using e.g., a Luer fitting. Of course, other types of needles and fittings, bayonet, screw threads, etc., may also be used. A finger flange  42  is advantageously provided at the back or top end of the body  12 . The first reservoir  14  is preferably filled with a flushing solution  50 , preferably sterile saline solution. The second reservoir  16  is preferably filled with a sclerosing solution  52 . The sclerosing agent may be sodium morruhate, sodium tetradecylsulfate, polilocanol, chromated glycerine, polyiodine iodine, hypotonic saline, Lauromacchogal, Abtysisclerol or other known sclerosing agent, in solution.  
         [0028]    The syringe assembly  10  may advantageously be pre-filled with the solutions  50  and  52 , with an end cap  62  on the end tube  34 , to prevent leakage during shipment and storage, and to maintain sterility. An over package, envelope, or container  90 , may optionally be provided, enclosing the syringe assembly  10 , to further maintain sterility of the reservoir contents. With the reservoirs  14  and  16  filled, the plungers  18  and  20  are fully withdrawn. FIGS. 1 and 2 show the plungers at intermediate positions, for purposes of illustration. As shown in FIGS.  5 - 7 , the end cap  62  has plugs  64  and  66  on a neck  68 . The cylindrical body  70  of the end cap  62  surrounds, and is spaced apart from the neck  68  via a gap  72 . The neck is attached to the front end or surface  74  of the end cap  62 . The end cap  62  makes a friction fit onto the end tube  34 , with the end tube  32  sliding into the gap  72 . The plugs  64  and  66  move into and plug the outlets  30  and  32 . Consequently, with the end cap  62  in place, the contents of the reservoirs  14  and  16  are sealed from the environment, and from each other. Providing the syringe assembly  10  as a prefilled unit avoids the need for the physician to separately fill the reservoirs.  
         [0029]    Referring to FIG. 2, although there is a direct connection between the first and second reservoirs  14  and  16  and the bore  36  in the end tube  34  via the first and second outlets  30  and  32 , the outlets  30  and  32  are plugged by the plugs  64  and  66  during storage. Any mixing between the solutions  50  and  52  after the end cap  62  is removed and the needle  38  attached, is inconsequential due to the relatively small size of the outlets  30  and  32 , the flow characteristics through the syringe assembly, and the short duration of use of the syringe assembly after the end cap is removed. As no valves or other flow control devices are needed in this embodiment, injection of the solutions  50  and  52  is quick and simple. The syringe assembly itself is also a simple and inexpensive design.  
         [0030]    As shown in FIGS. 9 and 10, in an alternative syringe assembly  90 , an end tube divider  92  extends from the outlets  30  and  32  to the very front end surface  95  of the end tube  98 . This divides the end tube  98  into two separate bores  94  and  96 . The end tube  98  preferably has a slightly tapering or conical outside wall. The end cap  100  shown in FIG. 10 has a complimentary inner wall  102 . When the end cap  100  is pushed on to the end tube  98 , it remains in place via the mating of the complimentary tapered surfaces and friction. The bottom end  105  of the end cap  100  contacts the front end surface  95  of the end tube  98  and seals off both of the separate bores  94  and  96 . This prevents leaking or mixing of the contents of the reservoirs. A resilient end cap pad or disk  104  may optionally be attached to the bottom surface of the end cap, to help seal the ends of the bores  94  and  96  when the end cap  100  is installed. The plunger seals  22  and  24  seal off the back end of the reservoirs.  
         [0031]    The syringe assembly may also be used to store and/or inject other combinations of solutions. In one such embodiment, the first reservoir contains a heparin solution and the second contains a saline solution.  
         [0032]    The needle  38  is preferably a 30-gauge needle. The needle preferably has a single lumen or bore  40  which connects to the outlets  30  and  32 . This allows the single needle to deliver both solutions, while having a small diameter, and piercing only a small opening in the skin and vein. The needle  38  may be made part of, or be provided already attached to, the syringe assembly, with the syringe assembly/needle combination optionally provided with the package  90 . As shown in dotted lines in FIG. 1, a needle cap  45  may be pushed or attached on to the tip of the needle. The needle cap helps to prevent piercing of the packaging, needle stick incidents, and leakage of the contents of the reservoirs out through the needle bore. The needle cap  45  may be resilient or rubber material. As the outlets  30  and  32  are both open into the bore of the needle, with this design, the contents of the reservoirs, over sufficient time, may diffuse into each other. If such diffusion must be entirely prevented, then the end cap  62  is installed in place of the needle, and the needle is installed only just before use. Alternatively, a needle  41  having two bores  40  may be used, as shown in FIG. 3, and with each bore separately connecting only to one of the reservoirs. With this design, separate flow paths from the outlets and through the tube  34  and needle  41  to the needle tip  43  are provided. Hence, in most ordinary uses any mixing of the solutions before injection is prevented, even with the needle attached to the syringe assembly during manufacture. However, the dual bore needle  41  necessarily requires a diameter larger than the single bore needle  38 . The needle cap  45  can be used on needle  41  as well. The syringe assembly  10  shown in FIGS.  1 - 2  and  4 - 7  is used by removing the end cap  62  and attaching the needle  38  to the end tube  34 . The design concepts described above may also be applied to a syringe assembly having three or more reservoirs.  
         [0033]    Referring to FIGS. 2 and 9, as there is an open pathway between the outlets  30  and  32 , either in the end tube  34 , or within the bore of the needle, in rare situations, inadvertent mixing of the contents of the reservoirs may occur. Specifically, if flow through the needle bore is restricted, and the sliding friction of the plunger end seals  22  and  24  is sufficiently low, and if one of the plungers  18  or  20  is rapidly pushed in, then some liquid may flow from one reservoir into the other reservoir, causing inadvertent mixing. When this occurs, pushing on one plunger, e.g.,  18 , causes the other plunger  20  to move back out of the reservoir  16 .  
         [0034]    This result can be avoided in several ways. One way is to have the needle bore diameter (the I.D. of the needle) be larger than I.D. of the outlets  30  and  32 . This will generally result in a flow resistance or pressure drop of flow through the needle bore, that is substantially less than flow resistance through either outlet  30  or  32 . Hence liquid flowing out of outlet  30  will not flow into outlet  32 . Typical hypodermic needles used with the syringe assemblies  10  or  90  range from Gauge  35  to Gauge  16 . Gauge  35  has an O.D. of 0.012 and an I.D. of 0.006 inches. Gauge  16  has an O.D. of 0.065 and an I.D. of 0.053 inches. The bore diameters in this range are then nominally 0.006-0.013 inches. Accordingly, if the outlets are 0.005 inches or less, back flow mixing can be avoided in most or all cases. Outlet diameters of 0.001 -0.005 inches are preferred for this range of needles. While both outlets typically will have the same diameter, one may be larger, depending on the liquid content characteristics, purity requirements, etc.  
         [0035]    Another alternative to prevent backflow mixing is use of one-way check valves or other flow restrictors  120 , as shown in FIG. 9. The valves  120  prevent inflow into the reservoirs through the outlets  30  or  32 . However, use of valves  120  requires that the reservoirs be filled from the top or back end, by removing the plungers, filling, and then replacing the plungers. A flow restrictor further increases flow resistance as a function of flow velocity, effectively limiting the speed of plunger movement and preventing back flow mixing.  
         [0036]    Another alternative to prevent backflow mixing is a one-way ratchet or brake  122  as shown in FIG. 1. The ratchet  122 , when engaged, prevents backward movement of the plunger. The ratchet may be disengaged temporarily, to fill the reservoir by pulling the plunger back up through the reservoir.  
         [0037]    In use for sclerotherapy, needle  38  is oriented with the angled tip surface  44  up and is inserted into the vessel or vein  80  to be treated. Once inserted, the angle or bevel surface  44  of the needle is facing up towards the skin  82 , as shown in FIG. 8. The first plunger  18  is pressed in, injecting the flushing solution into the vessel. The flushing solution displaces blood in the vessel, moving the blood away from the treatment site. Typically, the vein will no longer be visible once the blood is displaced. If the physician observes little or no change in appearance in the vein, then the needle is not properly located in the vein. The needle is then withdrawn and inserted at another location in the vein, before the sclerosing solution is injected. Injection of sclerosing solution outside of the vein can cause skin ulcerations. On the other hand, inadvertent injection of a flushing solution such as a saline outside of the vein creates no such risk of complications The use of flushing solution first, along with the change in appearance (or disappearance) of the vein, reduces potential complications resulting from injecting sclerosing solution outside of the vein.  
         [0038]    After the flushing solution is injected, and the physician observes the change in appearance of the vein, and with the needle  38  remaining in place in the vessel, the second plunger  20  is then pressed in, injecting the sclerosing solution  52  into the vessel. As the sclerosing solution  52  acts on the vessel walls, without significant presence of blood at the treatment site, complications, such as hyperpigmentation, are reduced.  
         [0039]    The volume of flushing solution  50  and sclerosing solution  52  used with each procedure may vary depending on the size of the vessel and other factors.  
         [0040]    After the treating physician determines that a sufficient amount of solutions  50  and  52  have been injected, the needle  38  is withdrawn from the vessel. A pressure dressing may be applied to the skin around the injection site. The needle may be relocated to another treatment site, on the same vessel, or on a different vessel. The reservoirs hold 1-8, 2-6 or 3-5 ml each. These volumes allow for multiple injections with a single syringe assembly  10 . Ultrasound treatment may be used on the areas treated over the 24-78 hour period following the above-described methods of sclerotherapy. This helps to further reduce or avoid bruising or potential hyperpigmentation.  
         [0041]    The methods described above may also be used with electrosurgical techniques, such as described in U.S. Pat. Nos. 5,695,495 and 6,293,944, incorporated herein by reference, or with ultrasound image-guided techniques to locate the injection site, or both.  
         [0042]    Thus, novel methods and devices have been shown and described. Various substitutions of steps and components may of course be made without departing from the spirit and scope of the invention. The invention, therefore, should not be limited, except by the following claims, and their equivalents.