WO2020076691A1

WO2020076691A1 - Dilating needle assembly

Info

Publication number: WO2020076691A1
Application number: PCT/US2019/054990
Authority: WO
Inventors: Avidan RAPPAPORT
Original assignee: Rappaport Avidan
Priority date: 2018-10-09
Filing date: 2019-10-07
Publication date: 2020-04-16

Abstract

A dilating needle assembly includes a needle; the precision nick dilating needle includes a needle shaft. A blade is fused to the shaft of the needle. A bead is fused to the base of the blade to dilate the channel while being advanced into the patient. An adjustable backstop is disposed about the needle and is moveable along the length of the needle to prevent excessive deep nicking. A textured hub is provided at a distal end of the needle to be gripped by the user and threaded over a wire during a procedure as the needle is advanced.

Description

DILATING NEEDLE ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and claims benefit of U.S. Provisional

Application No. 62/743,199 filed October 9, 2018 and entitled“Dilating Needle

Assembly,” which application is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] This invention is directed to an instrument for preparing a major vein to receive a catheter in the skin of a patient; and more particularly a needle assembly for providing a nick cut and dilating the opening.

[0003] Central line placement is a ubiquitous technique for the inpatient care of moderate to severely ill patients. The central line catheter, by way of nonlimiting example, is placed within a major vein to infuse medicine, blood, parenteral nutrition or measure a patient’s volume status of hydration. As is known in the art, the central line is placed with the Seldinger technique.

[0004] Routine Seldinger technique involves, in order:

1. Aspirating blood in a syringe with a needle properly placed in the central vein of the neck, chest, or groin (internal jugular or subclavian veins respectively).

2. Removing the syringe from the needle hub, while still holding the needle steady within the vein.

3. Manually threading a wire through the needle and loading a dilator onto the wire.

4. Free-hand cutting a properly sized placed incision along the wire with a

scalpel through skin, subcutaneous fat/tissue, and at times just through the deeper muscular fascia plane.

5. Running a rigid plastic dilator over the wire to enhance a channel for the catheter to pass through smoothly. 6. Threading the definitive central line catheter over the wire, through the channel created by steps 4 and 5 above, to a proper depth.

7. Removing the wire then securing the central line in place with suture and occlusive dressings.

[0005] The free hand incision step (4) does present significant peril in this process if not done correctly. Proper incision specifically requires a steady hand to guide the scalpel blade right along the wire to make a properly sized and deep cut which can be difficult depending on the patient’s skin, subcutaneous fat, tissue and muscle thickness and tissue quality. The difficulty can be magnified if the line must be placed in an emergency situation to deliver lifesaving medications to a patient in cardiac arrest with inadequate intravenous access while CPR is being performed. In this situation the line has to be placed deftly while“trying to hit a moving target”.

[0006] The prior art procedure has been satisfactory. However, the Seldinger technique requires proper instruction and repetition in order for the doctor to maintain the necessary skill level for correct catheter placement. Almost all physicians properly learn the Seldinger technique at some point during their medical school and/or residency. However, without training and repetition to maintain the appropriate muscle memory or“facile hands”; the skill can be lost. As a result, central line insertion often requires reliance on specialists such as intensivists, trauma/cardiac anesthesiologists, or interventional radiologists to perform the line placement for other physicians.

However, specialists may not always be available in rural settings, or in many emergency circumstances and therefore a doctor who is rusty in the procedure may be required to perform the technique under pressure resulting in an improper placement of the central line.

[0007] If the nick is done improperly, an incision may be too large which results in protracted bleeding and oozing from the site. Oozing catheter sites create additional nursing burden due to frequent dressing changes and holding pressure. The nick can also be too small which makes it difficult for the dilator to enter the vein in the first attempt. If dilation is unsuccessful, the site again results in bleeding and oozing creating the same problems as above. Lastly, if the incision is misplaced, even if cut to the proper size, this results in the free-hand execution not riding along the path of the wire. This again results in oozing and the forced insertion of the dilator with excessive force damaging the tissue. A skin bridge between the wire and where the misplaced incision was made complicates matters by requiring re-nicking which is hard to visualize and perform once the tissue being oozing from the first cut. Again, this may result in surrounding tissue damage. Furthermore, anticoagulation medicines such as

Coumadin (older) or Xarelto) compound this problem. Often the anticoagulation status of such patients is unknown or it is known, but such medicines cannot be stopped for clinical reasons. Nonetheless, if a central line is indicated it must be placed under a less than ideal anticoagulated circumstance.

[0008] Accordingly, an apparatus which overcomes the shortcomings of the prior art is desired.

BRIEF SUMMARY OF THE INVENTION

[0009] A dilating needle assembly includes a cannula or needle. A blade is disposed about the shaft of the needle. A bead is disposed at the base (trailing edge) of the blade to dilate the channel while the needle is advanced into the patient. An adjustable backstop is disposed about the needle and is moveable along the length of the needle to prevent excessive deep nicking. A textured hub is provided at a distal end of the needle to be gripped by the user and threaded over a wire during a procedure as the needle is advanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure would be better understood by reading written description with reference to the accompanying drawing figures, in which the reference numerals denote the similar structure and refer to the elements throughout in which:

FIG. 1 is a side plan view of a dilating needle assembly constructed in accordance with the invention;

FIG. 2A is a side plan view of a dilating needle assembly with protective sheath in accordance with the invention; FIG. 2B is a side plan view of the protective sheath of FIG. 2A;

FIG. 3A is a perspective view of a dilating needle, constructed in accordance with a third embodiment of the invention, in an open position;

FIG. 3B is a perspective view of a dilating needle, constructed in accordance with a third embodiment of the invention, in a closed position;

FIG. 4 is a front elevational view of the needle assembly constructed in accordance with the third embodiment of the invention;

FIG. 5 is a side elevational view of a needle assembly constructed in accordance with another embodiment of the invention;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5; and

FIG. 7 is a side elevational view of the needle assembly constructed in accordance with another embodiment of the invention in use;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As seen in FIG. 1 , dilating needle assembly 150 includes a hollow cannula or needle 6 having a beveled proximal end 1 which forms the leading edge of a needle 10. The proximal end 1 is beveled and (as an input port for needle 6) receives a wire 50 already within a central vein. The distal end 1 may be gel tipped for safety.

[0012] A shaft of needle 6 has markings 7 thereon to indicate a depth at which the needle 10 is inserted within the vein. In a preferred embodiment, the markings are spaced a centimeter apart from each other, the markings may be medically approved ink, beveled scratched indents or the like along needle 6, or a combination of both ink and beveling or scratching.

[0013] A blade 2 is affixed to the shaft of needle 6. In a preferred embodiment, blade 2 is shaped as a half arrow and sized and tapered such that it cannot create a nick any wider than that of the definitive catheter. Accordingly, the size of the half arrow will vary as a function of the catheter to be inserted into the central line. This dimensional constraint mitigates many problems resulting from the prior art free hand nicking of the skin and the Seldinger method when done incorrectly. Nicks that are too big, too small or inaccurately placed leave a skin bridge that retards passage of other dilators or the definitive catheter. This can lead to the ultimate damage of vessels or precious surrounding structures. Furthermore, they may create a bloody, oozy, catheter site which may invite infection and make insertion at the site hard to do because of the lack of a clearly visible access. Blade 2 provides a cleaner cut mitigating these problems.

[0014] A bead 3 is affixed to the base (proximal end) of blade 2. In a preferred embodiment, the blade is fused to the shaft of needle 6 and bead 3 is fused to blade 2. The narrow end (lead or cutting end) of blade 2 faces towards distal end 1 of needle 6. Bead 3 may be made of a hard plastic or metal and serves to further to dilate the channel while needle 10 is advanced into the patient and prevents snagging or indiscriminate cutting of surrounding structures by the blade when pulled on the way out. The proximal end of bead 3 may be chamfered and has an outer maximum diameter no greater than the diameter of the central line catheter with which the overall medical process is associated. The outer maximum diameter of bead 3 is also greater than or equal to the maximum height of blade 2 as measured from needle 6. Again, this prevents surrounding structure damage or oozing from the site.

[0015] An adjustable backstop 4 is slidably disposed about the shaft of needle 6 proximal from bead 3. The positioning of backstop 4 prevents excessively deep nicking. During the process, the nicking should occur just at the skin 70 and the subcutaneous fatty tissue or through the initial muscle fascia plane. This depth can be correlated utilizing marking 7 along the shaft of needle 6. The adjustable backstop 4 is moved to the desired depth and affixed to needle 6 at that position by clamping or other known technique to prevent over insertion of needle 10.

[0016] A textured hub 5 is placed at the distal end of needle 6 to be gripped and threaded over the wire 50 during advancement of needle 10 along wire 50. The shaft of needle 6 provides a needle for receiving a wire. [0017] Reference is now made to FIG. 2 in which a second embodiment of the invention is provided. The primary difference between the needle assembly of FIG. 1 and the needle assembly of FIG. 2 is inclusion of a sheath 100 to facilitate threading of wire 50 through needle 6; a sheath 100 may be added. Sheath 100 also has the secondary function of keeping distal end 1 isolated from many contaminants as well as protecting the fingers of the user from the distal end.

[0018] Sheath 100 includes a main hollow shaft 102 which circumscribes needle 6 when in position. A distal end of sheath 100 includes a funnel 104 in communication with shaft 102. The angled edges of funnel 104 guide the wire 50 towards the open distal end of needle 6 for threading the wire through dilator needle assembly 10.

[0019] Because the funnel 104 would prevent insertion of dilator needle assembly into the vein 60, it must be removable. In a preferred embodiment, a score line 106 is provided along the length of sheath 100 along with a pull tab 108 so that pulling on pull tab 108 causes sheath 100 to break apart along score line 106. This allows easy removal just ahead of the final insertion step when utilizing dilator needle assembly 10.

[0020] In a preferred non-limiting embodiment, sheath 100 is made from a

disposable thin, yet ridged plastic capable of scoring and removal. Preferably, a low cost plastic is utilized because of the disposable nature of the sheath. Additionally, treated papers as known in the cup art by way of example, similar in properties to those used to make paper cups may also be used.

[0021] To enhance precision, the practitioner may utilize ultrasound to facilitate the depth finding of the vessel. Accordingly, in a preferred nonlimiting embodiment, at least some of the inserted structure of dilating needle assembly 150 can be made from echogenic materials to enhance visualization of the tool. Once the depth is ascertained, moveable backstop 4 can be adjusted to control the specific depth of the insertion as backstop 4 has an outer diameter greater than the diameter of vessel 60 and any nick cut created by blade 2. It is possible that dilating needle assembly 10 alone may obviate the need for a subsequent rigid plastic dilation in some patients, but should be employed if so desired for deeper tissue channel creation. The textured grip of distal end 5 provides better control of needle 10. [0022] A needle assembly constructed in accordance with the invention mitigates the errors arising from the prior art methodology. Because the distal end of shaft 1 is a short beveled tip which can be gel coated to facilitate smooth passage along the wire, the third through fifth steps of the Seldinger technique can be done in one simple step. Once wire 50 is fit through the needle 10, the needle 10 can pierce the skin more precisely and with accuracy because the blade 2 automatically rides the wire. The blade 2 fused to the dilating bead 3 directly behind it is specifically sized to match diameter of the definitive central line. Therefore, whether a large or small central line is to be placed, the dilating needle can be manufactured as a custom sized apparatus that creates a channel matching the outer diameter of the catheter used in the follow-on procedure. The cut is not bigger and smaller removing the need for experimentation in size or damaging the patient through the insertion of a catheter into a wrong size nick. Needle assembly 10 automatically eliminates the possibility of too big or too small nick. The bead 3 also serves to protect the patient from inerrant cuts when removing needle 10 as it precedes the blade on the proximal end when being removed from the vein. Because bead 3 diameter is greater than the height of the blade, inadvertent cutting on the way out is prevented.

[0023] During the procedure, the existence of the exposed blade itself may pose destructive risk beyond the skin surface for deeper tissues and structures. Thus, the ability to cover the leading edge, cutting implement, is important. Therefore, in a third embodiment of the invention a structure, the dilating bead also serves a second purpose as a sheath for the blade; providing the necessary protection from the blade during the procedure. Reference is now made to Figs. 3A-4 in which a dilating needle assembly, generally indicated as 300, constructed in accordance with the third embodiment of the invention is provided. Like numerals indicate like structures from previous embodiments.

[0024] Dilating needle assembly 300 includes a blade 302 disposed at a distal end one of the needle 6. The blade 302 has a truncated arrow feather shape such that the narrow end (lead cutting end) of blade 302 faces towards distal end 1. A bead 303 is slidably mounted along needle 6 and is slideable between a first, open position (FIG.

3A) to a second, closed position (FIG. 3B). In a preferred nonlimiting embodiment bead 303 is teardrop shaped and has an outer diameter equal to or greater than the height of blade 302.

[0025] With this embodiment, during the early stages of the Seldinger technique, blade 302 is exposed (the open position) to cut as described above in accordance with the other embodiments of the invention. Once the cutting step is complete, bead 303 is then moved to the closed position sheathing blade 302 (shown in Phantom in Fig. 3B) to prevent unintentional cutting while dilating the vein. Because bead 303 becomes the leading-edge of needle assembly 300 with the blade 302 safely incorporated within the body of bead 303, dilating needle assembly 300 may safely be used as a dilator and push more deeply into subcutaneous tissues to create the desired channel depth.

[0026] During operation, bead 303 may be manually moved from the open position to the closed position. However, it is well within the scope of the invention and those skilled in the art to provide mechanical means for sliding bead 303 between positions such as a coaxially spring-loaded trigger, cautery or bovie electrical mechanism at the tip to create electrical hemostasis as the bead 303 is moved; or any variant thereof capable of moving bead 303 between positions.

[0027] During use, the needle assembly of the present invention simplifies the Seldinger technique by in effect facilitating the first five steps of the technique with a single one handheld assembly execution. The dilating needle assembly can be fixed and locked onto a more traditional aspirating needle running through the internal diameter of the dilating needle’s bore. Once the aspiration phase of the Seldinger technique is achieved, the syringe would be removed, the wire would then be

introduced to the vessel via the aspirating needle which would then be removed after unlocking the above described cutting dilator. This technique would just leave the dilating needle assembly threaded on the wire at which point, definitive cutting/dilating can be done as previously described.

[0028] Reference is now made to Figs. 5-7 in which a further embodiment of the dilating needle assembly is provided. The assembly includes a housing generally indicated as 520. Housing 520 includes a pre-torqued cuff 500 and a hub 512 disposed on either side of a score line 514. At least cuff 500 is movably disposed along needle 506 and/or wire 50 once detached at score line 514.

[0029] Hub 512 may be affixed adjacent the proximal end of needle 506. Hub 512 is formed with a tapered inner channel 516 to facilitate feeding wire 50 through the needle assembly. A blade 502 and bead 503 are formed on cuff 500. Blade 502 and bead 503 are integrated as part of housing 520; specifically cuff 500, bead 503 and blade 502 extend from hosing 520 in the distal direction of housing 520.

[0030] Cuff is separated from hub 512 at score line 514 during use. Cuff 500 is now slidably disposed about needle 506 and/or wire 50. In this way, bead 503 and the blade

502 travel along needle 506 and/or wire 50 with cuff 500. Given the small size of cuff 500 a flange 508 (sized to move blade 502 and bead 503 into a vein) is formed on cuff 500 to facilitate manual manipulation.

[0031] Structure within cuff 500 provides the pre-torque; a tension fit between cuff 500 and needle 506. When cuff 500 is slid sufficiently far for the blade 502 and bead

503 to extend beyond needle 506 to be mounted on wire 508 gap would be created by the difference between the outer diameter of needle 506 and the outer diameter of wire 50. This small distance can be enough to create a "skin bridge" defeating the purpose of using the needle assembly as described herein preventing the precise cut right along the wire into the skin provided by the needle assemblies described herein. Torqued cuff 520 includes an internal spring like structure for closing this gap and fixing cuff 500 directly to wire 50 with a tension fit; preventing the creation of a skin bridge as the leading-edge of blade 502 now rests along wire 50.

[0032] Needle 502, as well as each of the needles discussed above utilized in the Seldinger technique is by necessity sharp and creates a small skin incision. However the blade 502, because it extends form cuff 500, remains exposed creating a potential sharp threat. Bead 503 is formed with recesses 510 to receive blade 502 when the process is completed while still allowing bead 503 to perform its intended function. As a result, the most advanced portion of the tip of blade 502 working with bead 503 essentially creates a blunt tipped needle to protect the following blades 502 as well as potentially protecting the tip of needle 506 as bead 503 moves through the patient. [0033] It should be noted that if cuff 500 is not separated from hub 512, the device would operate substantially as discussed above with fixed bead/blade configurations of the previous embodiments. However the fusion of the cuff assembly, with bead and blade, to the hub which receives the wire saves the cumbersome step for the operator of having to thread a small wire 50 into a small hole within needle 506. The device can now simply be slid into position because it will already be mounted about the wire.

[0034] While the example of the preferred embodiment has been provided in connection with a central line catheter, it should be noted that as readily understood by those skilled in the art, that the term central line as used herein encompasses terms applicable to the ultimate delivery of any variation of catheter, sheath or needle to a central vessel. The described needle assembly is applicable across many medical sub specialties including, but not limited to, anesthesiology, interventional cardiology, interventional radiology, intensive care, general surgery, and cardiothoracic surgery. The vessels typically accessed by the above described assembly are venous, but may be used for the arterial systems as well.

[0035] Thus, while there have been shown, described and pointed out, novel features of the present invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form of detail are contemplated to the disclosed invention, which may be made by those skilled in the art without departing from the spirit and scope of the invention. It is the intention therefore to be limited only as indicated by the scope of the claims appended hereto. It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention, which as a matter of language, might be said to fall therebetween.

Claims

CLAIMS What is claimed is:

1. A dilator needle assembly comprising: a needle having a distal end and a proximal end; a blade fused to a shaft of the needle, the blade having a proximal end and a distal end; and a bead fused to the blade, the bead having a maximum outer diameter at least as great as a greatest height of the blade extending from the needle, the bead being disposed between the blade and the proximal end.

2. The dilator needle assembly of claim 1 , further comprising an adjustable stop slidably disposed about the needle between the bead and the proximal end.

3. The dilator needle assembly of claim 1 , further comprising a sheath, the sheath having a shaft circumscribing the needle; a funnel section communicating with a distal end of the sheath.

4. The dilator needle assembly of claim 1 , wherein the size of the bead being a function of a catheter to be inserted into a central line to be cut by the blade.

5. The dilator needle assembly of claim 2, wherein the bead is chamfered and at a proximal edge of the bead, the outer diameter of the bead is no greater than the catheter.

6. A dilator needle assembly comprising: a needle having a distal end and a proximal end; a blade fused to a shaft of the needle, the blade having a proximal end and a distal end; and a bead movable along the blade between a first position exposing the blade and a second position sheathing the blade, the bead having a diameter at least as great as a greatest height of the blade extending from the needle.

7. The dilator needle assembly of claim 6, further comprising an adjustable stop slidably disposed about the needle between the bead and the proximal end.

8. The dilator needle assembly of claim 6, further comprising a sheath, the sheath having a shaft circumscribing the needle; a funnel section communicating with a distal end of the sheath.

9. The dilator needle assembly of claim 6, wherein the size of the bead being a function of a catheter to be inserted into a central line to be cut by the blade.

10. The dilator needle assembly of claim 9, wherein the bead is chamfered and at a proximal edge of the bead, the outer diameter of the bead is no greater than the catheter.

11. A dilator needle assembly comprising: a needle having a distal end and a proximal end; a wire disposed within the needle and extending through at least the distal end; a bead a bead selectively slidably disposed to at least one of the needle and the wire; a blade selectively slidably disposed on at least one of the needle and the wire.

12. The dilator needle assembly of claim 11 , further comprising a housing disposed on the needle, the housing including a hub fixedly mounted to the needle and a cuff detachably affixed to the hub.

13. The dilator needle assembly of claim 12, wherein the blade is disposed on the cuff to extend therefrom, and the bead being disposed on the cuff.

14. The dilator needle assembly of claim 12, further comprising a score line for detachably connecting the hub to the cuff.

15. The dilator needle assembly of claim 14, further comprising a flange extending from said customer adjacent the score line.

16. The dilator needle assembly of claim 12, wherein the hub is tapered at a proximal end for receiving the wire.

17. The dilator needle assembly of claim 12, wherein the cuff is slideable upon the needle and the wire once separated from the hub.

18. The dilator needle assembly of claim 12, wherein the cuff is pre torqued to form a tension fit with at least one of the needle and the wire.

19. The dilator needle assembly of claim 12, further comprising a recess disposed within the cuff for receiving the blade.