Instrument and method for delivery of anaesthetic drugs Number:7,386,341 from the United States Patent and Trademark Office (PTO) owispatent

Title: Instrument and method for delivery of anaesthetic drugs

Abstract: A needle and catheter system, including components, is provided such that the position of an stimulating needle may be identified after insertion into the body of a patient by electrically stimulating and thus locating a specific nerve. Positioning of the stimulating needle while simultaneously controlling and monitoring the electrical impulses applied therethrough is made possible by a control device and monitor integral with the stimulating needle. When a specific nerve is located, the catheter is inserted through the needle to a point slightly beyond the distal tip of the needle. The catheter tip may then be manipulated and the optimum position for the catheter tip determined by applying an electrical impulse through the helical wire and/or the ribbon support wire to the proximal tip catheter, this electrical stimulation being utilized in determining the specific location of the catheter tip within the nerve. Once properly located, or at any time relative movement between the catheter and needle is not desirable, the catheter can be locked into position with a catheter lock which may be part of the stimulating needle hub. A catheter adapter is utilized to allow easy access to the catheter and introduction of fluid into the nerve of the patient through the catheter tip.

Patent Number: 7,386,341 Issued on 06/10/2008 to Hafer,   et al.

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Inventors:	Hafer; Fred (Shillington, PA), Vitullo; Jeffrey M. (Pottstown, PA), Harding; Richard L. (Reinholds, PA), Spinka; Mark J. (Reading, PA)
Assignee:	Arrow International, Inc. (Reading, PA)
Appl. No.:	10/441,867
Filed:	May 20, 2003

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Related U.S. Patent Documents

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	Application Number	Filing Date	Patent Number	Issue Date
	10188605	Jul., 2002	6973346
	09524467	Mar., 2000	6456874

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Current U.S. Class:	607/3
Field of Search:	607/3,43,46,48,115-117 606/129 600/554,585,548 604/20,117

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References Cited [Referenced By]

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U.S. Patent Documents

2987292	June 1961	Teson et al.
3550861	December 1970	Teson
3682162	August 1972	Colyer
4515168	May 1985	Chester et al.
4518383	May 1985	Evans
4540411	September 1985	Bodicky
4644960	February 1987	Johans
4801293	January 1989	Jackson
4824433	April 1989	Marz et al.
4973312	November 1990	Andrew
5007902	April 1991	Witt
5081990	January 1992	Deletis
5092344	March 1992	Lee
5135525	August 1992	Biscoping et al.
5284153	February 1994	Raymond et al.
5304141	April 1994	Johnson et al.
5423877	June 1995	Mackey
5489274	February 1996	Chu et al.
5782505	July 1998	Brooks et al.
5830151	November 1998	Hadzic et al.
5899891	May 1999	Racz
5902273	May 1999	Yang et al.
5976110	November 1999	Greengrass et al.
5989223	November 1999	Chu et al.
6104960	August 2000	Duysens et al.
6190370	February 2001	Tsui
6259945	July 2001	Epstein et al.
6298256	October 2001	Meyer
6325764	December 2001	Griffith et al.
6582441	June 2003	He et al.
6706016	March 2004	Cory et al.
6730083	May 2004	Freigang et al.
2002/0065481	May 2002	Cory et al.
2003/0158592	August 2003	Pajunk et al.

Foreign Patent Documents

	3102142		Aug., 1982		DE
	0759307		Feb., 1997		EP
	0966922		Dec., 1999		EP
	WO 9314710		Aug., 1993		WO
	WO 9833547		Aug., 1998		WO
	WO 9904705		Feb., 1999		WO

Other References

Boezaart et al., "A new technique of continuous interscalene nerve block," Canadian Journal of Anesthesia, Mar. 1999, pp. 275-281, vol. 46, No. 3, Canadian Anesthesiologists' Society Canada. cited by other . Sarnoff, S.J. and Sarnoff, L.C.: Prolonged Peripheral Nerve Block by Means of Indwelling Plastic Catheter Treatment of Hiccup. Dated 1950. cited by other . Sarnoff, S.J.: Functional Localization of Interspinal Catheters, Anesthesiology 11:300-866 (May) 1950. cited by other.

Primary Examiner: Manuel; George
Attorney, Agent or Firm: Amster, Rothstein & Ebenstein LLP

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Parent Case Text

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CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of prior U.S. patent application Ser. No. 10/188,605, filed on Jul. 2, 2002 now U.S. Pat. No. 6,973,346, which is itself a divisional of U.S. patent application Ser. No. 09/524,467 entitled INSTRUMENT AND METHOD FOR DELIVERY OF ANAESTHETIC DRUG filed on Mar. 13, 2000, now U.S. Pat. No. 6,456,874.

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Claims

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What is claimed is:

1. A medical-surgical instrument comprising: a. a needle having a central bore for providing access to a nerve of a patient and a needle hub disposed about a proximal end of the needle; b. a catheter for providing fluid flow access to and electrically stimulating the nerve of the patient, the catheter capable of being inserted into the patient through the needle; and c. a catheter lock attached to the needle hub for selectively holding said catheter stationary with respect to said needle or allowing said catheter to slide through said catheter lock and said needle, said catheter lock comprising a bore and an actuating portion, the catheter being inserted through the bore of the catheter lock and the needle central bore such that actuation of the actuating portion of the catheter lock causes the catheter lock to frictionally hold the catheter in place with respect to the catheter lock, the catheter lock frictionally holding the catheter at one of a plurality of locations along the length of the catheter.

2. The medical-surgical instrument of claim 1, wherein the needle further comprises a wire with a first end attached to a proximal end of the needle and a second end adapted to be connected to a source of electricity, for conveying electricity provided by the source of electricity to the needle.

3. The medical-surgical instrument of claim 1, wherein the catheter is inserted through the catheter lock and needle such that a distal tip of the catheter extends beyond a distal end of the needle.

4. The medical-surgical instrument of claim 1, wherein the catheter additionally comprises a central bore capable of bringing a liquid from a proximal end of the catheter to the nerve of the patient.

5. The medical-surgical instrument of claim 1, wherein the needle additionally comprises an electrically insulating covering on an outer surface of the needle.

6. The medical-surgical instrument of claim 1 wherein a proximal end of the catheter is inserted into and frictionally held by a catheter adapter, whereby a fluid delivery apparatus to supply a fluid to said catheter is attached to the catheter adapter.

7. The medical-surgical instrument of claim 1 wherein a proximal end of the catheter is inserted into and frictionally held by a catheter adapter, whereby a source of electricity to supply electricity to said catheter is conductively attached to the catheter adapter.

8. The medical-surgical instrument of claim 1 wherein the catheter further comprises support means for supporting the catheter.

9. The medical-surgical instrument of claim 8 wherein the support means comprises a helical wire underlying the catheter.

10. The medical-surgical instrument of claim 9 wherein the support means is electrically conducting.

11. The medical-surgical instrument of claim 1, wherein the catheter lock is removably attached to the needle.

12. The medical-surgical instrument of claim 11 wherein direct fluid injection through the needle hub may be achieved after removing the catheter lock.

13. A medical-surgical instrument comprising: a. a needle having a central bore and a hub disposed about a proximal end of the needle; b. a catheter having a proximal end, a distal end, an electrically conducting distal tip, and a lumen for allowing fluid flow through the catheter, the catheter adapted to conduct electricity from the proximal end of the catheter to the distal tip of the catheter; c. a catheter lock comprising a bore and an actuating portion; and d. the catheter being inserted through the bore of the catheter lock and the needle central bore such that actuation of the actuating portion of the catheter lock causes the catheter lock to frictionally hold the catheter in place with respect to the catheter lock, the catheter lock frictionally holding the catheter at one of a plurality of locations along the length of the catheter.

14. The medical-surgical instrument of claim 13, wherein the catheter further comprises a bore for conveying a liquid.

15. The medical-surgical instrument of claim 14, wherein the catheter further includes a liquid exit proximate the distal tip for allowing delivery of a liquid to a patient proximate the distal tip of the catheter.

16. The medical-surgical instrument of claim 14, wherein the catheter further includes a liquid exit as an integral part of a distal tip of the catheter for allowing delivery of a liquid to a patient through the distal tip of the catheter.

17. The medical-surgical instrument of claim 13, wherein the catheter further comprises a conducting wire extending from the proximal end of the catheter to the electrically conducting distal tip of the catheter.

18. The medical-surgical instrument of claim 13, wherein the conducting wire is approximately parallel with the catheter in an axial direction for a majority of the length of the conducting wire.

19. The medical-surgical instrument of claim 13, wherein the conducting wire is helically shaped.

20. The medical-surgical instrument of claim 13, wherein the catheter comprises an electrically insulating thermoplastic sheath and a supporting structure disposed in supporting contact with the thermoplastic sheath along at least substantially the entire length of the thermoplastic sheath.

21. The medical-surgical instrument of claim 20 wherein the supporting structure is a helical wire.

22. The medical-surgical instrument of claim 21 wherein the helical wire is electrically conducting.

23. The medical-surgical instrument of claim 13, the catheter lock further comprising: a. a stationary body portion attached to the hub and extending proximally therefrom; b. the actuating portion comprising a rotatable body portion rotatably engaged with the stationary body portion; and c. means for firmly grasping a portion of the catheter disposed through the bore of the stationary body portion, said means being engaged and disengaged by the actuating portion.

24. The medical-surgical instrument of claim 23, wherein the catheter additionally comprises a central bore capable of conveying a liquid along substantially the entire length of the catheter.

25. The medical-surgical instrument of claim 23, wherein the needle additionally comprises an outer surface between the proximal end and a distal end of the needle, a portion of the outer surface of the needle being covered in an electrically insulating covering.

26. The medical-surgical instrument of claim 23, further comprising a conducting wire extending from the proximal end of the catheter to the distal end of the catheter and conductively connected to the distal tip.

27. The medical-surgical instrument of claim 26, wherein the conducting wire is substantially parallel to the axis of the catheter.

28. The medical-surgical instrument of claim 26, wherein the conducting wire is connected to the proximal end of the catheter.

29. The medical-surgical instrument of claim 23 wherein the catheter comprises an electrically insulating thermoplastic sheath and a supporting structure disposed in supporting contact with the thermoplastic sheath along at least substantially the entire length of the thermoplastic sheath.

30. The medical-surgical instrument of claim 29 wherein the supporting structure is a helical wire.

31. The medical-surgical instrument of claim 30 wherein the helical wire is electrically conducting.

32. The medical surgical instrument of claim 30 wherein the helical wire extends distally of the thermoplastic sheath such that the distal end of the catheter comprises the helical wire not covered by the thermoplastic sheath.

33. The medical-surgical instrument of claim 30 wherein a conducting wire is conductively connected to the helical wire near the proximal end of the catheter.

34. The medical-surgical instrument of claim 30 wherein the helical wire extends proximally of the thermoplastic sheath such that the proximal end of the catheter comprises the helical wire not covered by the thermoplastic sheath.

35. The medical-surgical instrument of claim 30 wherein the proximal end of the catheter is received within catheter adapter means for allowing connection of a fluid delivery apparatus.

36. The medical-surgical instrument of claim 30 wherein the proximal end of the catheter is received within catheter adapter means for allowing connection of a source of electricity to the proximal end of the catheter, the catheter adapter includes an insulated wire and connector adapted to be connected to a source of electricity.

37. The medical-surgical instrument of claim 13, further comprising an insulated wire, a first end of the insulated wire is conductively connected to the proximal end of the needle and a second end of the insulated wire is adapted such that it can be connected to a source of electricity, such that the needle is capable of conveying electricity provided by the source of electricity from the proximal end to a distal end of the needle.

38. The medical-surgical instrument of claim 13, wherein the catheter is inserted through the catheter lock and needle central bore such that the distal tip of the catheter extends beyond a distal end of the needle.

39. The medical-surgical instrument of claim 13, wherein the catheter lock is removably attached to the needle hub.

40. The medical-surgical instrument of claim 39 wherein direct fluid injection through the needle hub may be achieved after removing the catheter lock.

41. A medical-surgical instrument comprising: a. a needle having a central bore and a hub comprising a distal end disposed about a proximal end of the needle, the hub further comprising a proximal end; b. a catheter having a proximal end, a distal end and an electrically conducting distal tip, the catheter adapted to conduct electricity from the proximal end of the catheter to the distal tip of the catheter, the catheter further comprising a lumen permitting fluid flow through the catheter; c. a catheter lock comprising a bore and an actuating portion, the catheter lock being attached to the proximal end of the needle hub in such a way that the catheter lock is capable of easily being unattached from the needle hub; and d. the catheter being inserted through the bore of the catheter lock and the needle central bore such that actuation of the actuating portion of the catheter lock causes the catheter lock to frictionally hold, at one of a plurality of locations along the length of the catheter, the catheter in place with respect to the catheter lock.

42. The medical-surgical instrument of claim 41 wherein direct fluid injection through the needle hub may be achieved after removing the catheter lock.

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Description

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BACKGROUND OF THE INVENTION

This invention relates to medical surgical instruments and a method of utilizing medical-surgical instruments for delivery of an anaesthetic drug. The invention is more particularly concerned with instruments and methods for use in the delivery of an anaesthetic for use as a nerve block.

A nerve block may be achieved through the administration of variable quantities of an anaesthetic agent to the plexus of a nerve. Since the nerve plexus is a very fragile structure, not capable of simple repair or reconstruction, it is crucial to do as little damage as possible in locating the point at which the plexus may be contacted.

It has been proposed to use a needle to locate the nerve in the usual way, and then to insert anaesthetic through the needle so that it emerges from the tip of the needle and contacts the nerve. An alternative procedure involves the proper positioning of the needle and the introduction of a stimulating catheter through the needle. Once properly placed adjacent the nerve and into the plexus sheath of the patient, the stimulating catheter may then be used to deliver variable amounts of anaesthetic for use as a nerve block.

It has also been proposed that an integral conductive wire be contained in the catheter, through which an electrical current may be applied to determine correct positioning of the catheter once it has been inserted through the needle. An electrical impulse sent through the conductive wire is utilized in determining proper placement of the tip of the catheter and, thus, the point at which the anaesthetic will be delivered.

Certain disadvantages exist with regard to the above referenced methods and the apparatus available to accomplish such methods. Most important among these is a danger associated with the uncertainty regarding the position of the needle tip. Such uncertainty could lead to nerve damage in manipulating the tip of the needle without knowing its position relative to nerves in the patient's body. This uncertainty can be related to `leakage` of electricity from the needle, i.e. the electricity being applied to the needle is not exiting the needle at the tip but rather it is exiting at an unintended portion of the needle. Placement of the catheter can have similar difficulties. The catheter itself can also be unwieldy as it is usually of a very small diameter and needs to be packaged in a wound position.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a catheter system is provided comprising: (a) a needle; (b) a catheter; and (c) a multipurpose connector. Each of these structures may be provided with a conductive element capable of allowing electrical contact to any other structure.

The needle has a distal end and a proximal end. The distal end of the needle terminates in a beveled aperture having a sharp tip adapted for insertion into a nerve sheath of a patient so as to abut the nerve plexus. Contained in the needle and co-terminus therewith at the distal end is a removable stylet utilized in easing insertion of the needle into the patient. The proximal end of the needle is provided with a hub portion used for gripping the needle as well as for accessing the central bore of the needle. The needle, being of metal construction, is electrically conductive along its entire length. A non-conductive material may be used to coat the outer surface of the needle, leaving exposed at least the distal tip of the needle, such that electrical voltage is not expended in unnecessary places.

A control device may be associated with the stimulating needle. The control device allows the operator to exercise control over the electrical stimulating pulse being applied to the nerve of the patient without removing either hand from the stimulating needle. Associating the control device directly with the stimulating needle has many advantages, including allowing the person inserting the needle to concentrate all of his attention on the patient and the stimulating needle without the need to operate or direct the operation of a separate, i.e. remote, stimulating control apparatus. In addition, a display may also be associated with the stimulating catheter. Such a readout would provide the operator with information as to the electrical impulse being applied to the patient's nerve. Again, the ability to focus on the single needle structure instead of referencing an independent readout remote from the stimulating needle allows for effective and safe operation of the stimulating needle and/or the stimulating catheter.

The stimulating catheter is adapted for insertion through the hub portion and within and through the needle, with the distal end of the catheter capable of protruding out of the needle's distal end. The catheter is formed primarily of a thermoplastic or related material which may be supported by a tightly wound helical wire. The helical wire can extend beyond the sheath material of the catheter at either or both the proximal and distal ends of the sheath. The sheath either alone or in combination with the helix formed by the helical wire, leaves the center of the catheter structure available as a conduit. This central conduit or lumen of the catheter allows for administration of anaesthetic to the proximal end of the catheter. The wire coil may be covered with an insulating material other than the thermoplastic cover. This insulating material, e.g. TEFLON, may surround the entire circumference of the wire as it is formed, prior to being coiled. Alternatively, this insulating material may be applied to the wire after it has been formed into a helical shape. In either case, the insulating material is typically much thinner than the thermoplastic cover applied after coiling of the wire.

The proximal end of the catheter may be inserted into a multipurpose connector. Once the proximal end of the catheter is inserted into the retaining portion of the multipurpose connector, the multipurpose connector may be manipulated to rigidly capture the proximal end of the catheter. The structure of the multipurpose connector allows the proximal end of the catheter to be accessed by a syringe or other apparatus for injecting fluid through the catheter. The multipurpose connector is also provided with electrical connections which electrically contact the helical wire of the catheter or other electrically conducting portions of the catheter. These electrical contacts allow a voltage to be applied to a conducting portion of the catheter despite the presence of the multipurpose connector over the proximal end of the catheter.

Another component that may be used in conjunction with the stimulating needle and the catheter system is a catheter lock. The catheter lock fits over the catheter and allows the catheter to slide therethrough when `unlocked`. When actuated, i.e. `locked`, the catheter lock firmly grips whatever portion of the catheter it is on when actuated. This gripping function may be used to securely hold the catheter especially when it is desired that the catheter be maintained in a given position. One of the ways in which the catheter lock can be used is in conjunction with the stimulating needle. Attachment of the catheter lock to the proximal end of the gripping hub of the stimulating needle allows for the catheter to be manipulated with respect to the stimulating needle or rigidly fixed in place with respect to the stimulating needle.

It is therefore an object of the present invention to provide a stimulating needle and stimulating catheter system including components, such that the position of a needle may be identified by electrically stimulating and thus locating a specific nerve. When a specific nerve is located, the stimulating catheter is inserted through the needle to a point slightly beyond the distal tip of the needle. The catheter tip may then be manipulated and the optimum position for the catheter tip determined by applying an electrical voltage to the conducting distal tip of the catheter, this electrical stimulation being utilized in locating the specific location of the catheter tip with respect to the nerve. Once optimum placement is achieved, the catheter is utilized for continuous administration of anaesthetic. At any time prior to this positioning procedure, when it is desired to hold the catheter in a particular place, actuation of a catheter lock structure allows this to be accomplished. In addition, once desired placement of the catheter is achieved, the stimulating needle may be removed in order to prevent it from doing any damage to the tissues of the patient.

It is a further object of the present invention to allow the person using the system to be able to easily vary the current being applied to the patient's nerve. Such a varying of the electrical impulses would be achieved without having to divert the operator's attention away from the apparatus being inserted into the patient. Also, a readout allows the operator to monitor the electrical impulses being applied to the nerve of a patient. The readout, too, is associated with the needle and allows monitoring of the electrical stimulation signal with a minimum of distraction from the insertion of the apparatus.

Some of the objects of the invention having been stated above, other objects will become evident as the description proceeds below, when taken in connection with the accompanying drawings as best described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the needle and stylet, with the needle inserted into the nerve sheath;

FIG. 1A is an end-on elevational view from the distal end of the needle structure, showing a detail of the tip of the needle, the tip of the stylet the and non-conductive needle material covering the region of the needle between the proximal ends;

FIG. 1B is a top view of the needle, with only a portion of the hub shown and the stylet removed, most of the needle being shown in section at section line 1B-1B;

FIG. 1C is a detail of the needle tip;

FIG. 1D is a side elevational view of the inner stylet;

FIG. 2 is a side elevational view of the catheter;

FIG. 3 is an enlarged version of FIG. 2, except that the catheter sheath is partially cut away to better show the structure of the helical wire, only portions of which are shown;

FIG. 4 is a side elevational view of the multipurpose connector in section, with the proximal end of the catheter inserted therein but not yet rigidly held in place;

FIG. 5 is a perspective view of the metal washer, multipurpose connector wires and sealing assembly of the multipurpose connector;

FIG. 6 is a side elevational view of the metal washer, multipurpose connector wires and sealing assembly of the multipurpose connector;

FIG. 7 is a side elevational view of an alternate embodiment of the multipurpose connector, with the proximal end of the catheter inserted therein but not yet rigidly held in place and the distal end of the catheter also shown with much of the intervening catheter cut away;

FIG. 8 is a side cross-sectional view of an alternate embodiment of the multipurpose connector in section, with the proximal end of the catheter inserted therein but not yet rigidly held in place;

FIG. 9 is a side elevational view of the catheter disclosing some inner structures therein in partial cross-section, an electrical connection hub and an electrical connection plug;

FIG. 10A is an side elevational detail of the slug type distal tip shown inserted into the distal end of an alternate version of the catheter, the catheter is in section;

FIG. 10B is cross sectional detail view of the helical support wire of the catheter showing the electrically insulating coating disposed thereon as discussed in reference to an alternate embodiment;

FIG. 10C is a side elevational detail of an alternate embodiment of the slug type distal tip shown inserted into the distal end of an alternate version of the catheter, the catheter is in section;

FIG. 11 is a perspective view of a first embodiment of a catheter lock shown in the unlocked position;

FIG. 12 is a perspective view of the first embodiment of the catheter lock shown in the locked position;

FIG. 13 is an end-on view of the first embodiment of catheter lock shown in the unlocked position;

FIG. 14 is an end-on view of the first embodiment of catheter lock shown in the locked position;

FIG. 15 is an exploded detail view the first embodiment of the catheter lock showing each of the components thereof;

FIG. 16 is a perspective view of a second embodiment of a catheter lock shown in the unlocked position;

FIG. 17 is a perspective view of the second embodiment of the catheter lock shown in the locked position;

FIG. 18 is an end-on view of the second embodiment of the catheter lock shown in the unlocked position;

FIG. 19 is an end-on view of the second embodiment of the catheter lock shown in the locked position;

FIG. 20 is an exploded detail view the second embodiment of the catheter lock showing each of the components thereof;

FIG. 21 is a side elevational view of the stationary body portion of the second embodiment of the catheter lock including the cylindrical extension portion thereof;

FIG. 22 is a side elevational view of the needle and stylet, with the needle inserted into the nerve sheath;

FIG. 23 is a perspective view of a tunneling device with integral gripping hub and skin bridge;

FIG. 24 is a side elevational view of the needle, needle hub and catheter lock extending proximally therefrom;

FIG. 25A is a side elevational view of one embodiment of the catheter lock according to the present invention;

FIG. 25B is an end view of one embodiment of the catheter lock according to the present invention;

FIG. 26 is a side elevational view of one embodiment of the needle hub extension for supporting structures used in controlling the electrical impulse being supplied to the patient;

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIG. 1, there is shown portions of a human body 10 containing a nerve 12 located subcutaneous to adjacent skin surface portion 14. In this example of use, a needle assembly 16 has been inserted into a human body 10 for the purpose of locating a nerve 12. The stimulating needle assembly 16 comprises a needle 18 and a central stylet 20 which extend coaxially of one another. The needle 18 is a metal needle which is joined at its rear end to a hub 22 of a plastic material. The needle 18 is hollow and projects a distance forwardly of the hub 22.

The needle 18 has three portions along its length. The major portion of the needle is the central portion 24 thereof. This central portion 24 of the needle is wrapped on the outside surface thereof in an insulating coating 26 which will not conduct electricity. This coating 26 is shown in FIG. 1 as being divided into sections of alternating color 28 and 30. Each of these sections is of a known, specific, length. Such colored sectioning enables the user to determine the extent of penetration of the tip 32 of the needle 18. Alternatively, the coating 26 may be clear and the underlying surface of the needle 18 may be marked, e.g. with alternating colors or other depth markings.

The remaining two portions of the needle 18 are the distal end 34 and the proximal end 36. At its proximal end 36, the needle 18 extends within the hub 22 where it is secured, such as by molding the hub around the needle. Between the insulating coating 26 of the central portion of the needle 24 and the plastic hub 22 the proximal end 36 of the needle 18 may be exposed such that electrical contact with the remainder of the needle may be achieved by contact with the exposed proximal end 36. The bore through the needle 38 opens into an axially-aligned bore 40 through the hub 22 of the same diameter as the needle bore 38. The rear end of the bore 42 is enlarged and tapered to provide a female Luer opening 44 for use in receiving the stylet 20 and stylet hub 21. The hub 22 is provided with an axially-extending slot or keyway 25 formed in the outer surface of the hub, on that side of the hub to which the tip 32 of the needle 18 is inclined.

As shown in FIG. 1C, the distal end 31 of the needle 18 is bent downwardly, the distal end 34 of the needle being cut such that it makes an angle .theta. with the axis of the major part of the needle. This inclined end of the needle provides it with a tip 32 constituting a sharp point that readily pierces body tissue. In this embodiment, the distal end 34 of the needle is not covered by any electrically insulating material and is in electrical contact, by way of the covered central portion 24, with the proximal end 36 of the needle. The insulating coating 26 prevents the flow of electricity radially out of the central portion 24 of the needle, but allows the flow of electricity axially along the length of the needle 18.

As best exemplified in FIG. 1D, the inner stylet 20 is formed of a solid metal needle. The distal tip 45 of the stylet 20 is cut to have the same sharp tip angle .theta. as the tip 32 of the needle. Joined to the proximal end of the stylet 20 is a stylet hub 21 of plastic material. The stylet 20 is smaller in diameter than the outer needle 18. The connector 46 of the stylet hub 21 which grasps the stylet 20 is of generally cylindrical shape. The forward end of the connector 46 has a Luer taper 48 that is dimensioned to fit within the Luer-tapered opening 44 in the needle hub 22. A short peg or key 50 of rectangular section is provided along the lower side of the stylet hub 21, as viewed in FIG. 1. The peg 50 extends axially of the stylet hub 21, being spaced outwardly by a small gap from its Luer-tapered section 48. The peg 50 is aligned with respect to the stylet hub 21 and stylet 20 such that, when the peg is engaged in the slot 25 of the needle hub 22, the plane of the inclined tip 45 of the stylet 20 lies in the same plane as the inclined tip 34 of the needle. The combined sharp tips of the needle and stylet readily pierces body tissue while the stylet, occupying the center bore 38 of the needle, prevents any tissue from entering the needle bore 38.

Also shown in FIG. 1 is an electrical connector 52, which may be in the form of an alligator clip which conveys electrical impulses from an anaesthetic nerve stimulator 17 to the proximal end of the needle 36.

FIG. 1A is an end on view of the tip of the needle assembly 16, showing the inclined tip of the needle 32 and the inclined tip 45 of the stylet 20. Also shown is the insulating coating 26. FIG. 1B is a detail of the needle 18 of the needle assembly, with the stylet 20 removed and only showing a small portion of the hub 22. In addition, the needle 18 of FIG. 1 has been sectioned along section line 1B of FIG. 1A. FIG. 1B shows the relationship of the insulating coating 26 (of exaggerated thickness) to the various portions of the needle 18.

Referring next to FIG. 2, there is shown a catheter assembly 54. The catheter assembly 54 is of a diameter which allows the assembly to be inserted through the needle assembly 16 and into the body of the patient. The catheter assembly 54 is primarily defined by a sheath 56 formed from a thermoplastic or similar material. A helical coil of wire 58 may also be utilized in conjunction with catheter sheath 56. As best shown in FIG. 3, helical wire 58 possesses three portions. A proximal portion 60, a central portion 62 and a distal portion 64. For its entire length, catheter assembly 54 defines a central bore 66 through which a liquid may freely pass. In addition, the helical wire 58 occupies only the peripheral portion of the central bore 66, thus maintaining the presence of central bore 66. This central bore 66 can also be seen to be extended beyond the catheter sheath by the presence of the helical wire 58. The helical wire 58 is not a necessary element of the catheter assembly 54. Rather, the helical wire can be eliminated, especially where the catheter is of sufficient strength so as to support itself.

Also occupying the central bore 66 of the catheter assembly 54 is ribbon wire 57. Ribbon wire 57 has two primary functions. The first of these functions is to prevent wire helix 58, if present, from being hyperextended. This function is accomplished by rigidly attaching ribbon wire 57 to distal tip 72, discussed more fully below, and to the proximal portion 60 of the helical wire 58. Attachment of the ribbon wire 57 at these portions of the helical wire will prevent the helix from being stretched in such a way as to permanently deform the wire. The second function of the ribbon wire 57 is to conduct electricity from the proximal portion of the catheter to the distal tip 72 of the catheter. This conduction of electricity may be supplemental to the electrical conduction of the wire helix 58 or it may be as an alternative to the electrical conduction provided by the wire helix. This interchangeability is obvious, given the fact that the wire helix 58 and the ribbon wire 57 both extend from the proximal end of the catheter to the distal tip 72. Thus, the wire helix 58 and the ribbon wire 57 are alternatives for conducting an electrical impulse from one end of the catheter assembly 54 to the other. If one of these two wires is present to accomplish this, there is no need for the other one.

The central portion 62 of the helical wire 58 is completely covered by the catheter sheath 56. The proximal portion 60 of the helical wire has no distinguishing features except that it is short relative to the central portion of the remainder of the catheter assembly 54 and is not covered by the catheter sheath. Proximal portion 60 of helical wire 58 can be electrically contacted. This can be accomplished by leaving it exposed as in FIG. 2 or by providing an electrical contact such as a wire, as will be discussed below.

In an alternate embodiment of the apparatus, the wire coil may be covered with an insulating material 59 other than or in addition to the thermoplastic cover provided by the catheter sheath 56. This additional insulating material 59, e.g. PTFE (Polytetrafluoroethylene) "TEFLON", surrounds the entire circumference of the wire as it is formed, prior to being coiled. Alternatively, the thin insulating coating 59 can be applied after the wire is formed into a helical coil. Such an insulating material 59 is typically much thinner than the thermoplastic cover applied to the entire coil after the wire coil is formed. In addition, such an insulating material 59 is typically directly bonded to the surface of the wire. By coating the wire helix 58 and other portions of the present apparatus which are electrically conducting and may come in contact with the tissues of a patient with an insulating material it becomes possible to very precisely control the size and location of the conducting portions of the apparatus. This control is accomplished by removing the thin insulating material 59 only from the precise portions of the apparatus which are to deliver electrical impulses to the tissues of a patient. In addition, with only the relatively small portion of the conducting portions of the apparatus exposed, the voltage density achieved at that point is high relative to the power of the electrical impulse supplied.

The distal portion 64 of the helical wire, which is short relative to the remainder of the catheter assembly 54 and not covered by the catheter sheath 56, has several features associated therewith. Where the helical wire 58 exits the catheter sheath 56 at the distal end thereof, the helix maintains the tightly wound nature of the proximal 60 and central 62 portions of the wire. This tight helix continues for a short distance before the helix opens up at an open helix portion 68. The open helix portion 68 continues for several revolutions of the helix, before the tightly wound structure returns for the distal end 70 of the distal portion 64. Attached to the distal end 70 is a distal tip 72 which is a piece of rounded metal. As discussed above, distal tip 72 may also or alternatively have ribbon wire 57 attached thereto. As with the helical wire 58, the distal tip is conducting and can either be completely bare of insulation or be substantially covered with thin layer 59 of insulating material, e.g. PTFE, and have a specific portion uninsulated.

An issue with some catheters of the type described herein arises due to the method in which they are packaged. Due to their length, it is necessary to coil the catheter. The natural shape of these catheters being straight and the materials of which they are made typically being quite resilient, improper removal of the catheter from the packaging may result in uncontrolled uncoiling of the catheter which, in turn, can lead to safety and sterility problems. A catheter packaging clip may be provided for retaining catheter 54 to prevent rapid uncoiling. In one embodiment, the catheter packaging clip may have a surface for gripping the clip as well as integral tunnel for retaining catheter 54 in such a way that rapid uncoiling can be prevented. In a second embodiment, a catheter packaging clip may have dual gripping portions but a tunnel similar to that of the alternate embodiment. The clip may be packaged with the catheter 54.

Referring next to FIG. 4, there is shown a catheter adapter 74. Accessing the central bore 66 of the catheter assembly 54 would be nearly impossible given the diameter of this structure. This being the case, a catheter adapter 74 is needed to provide access to the central bore 66 of the catheter assembly 54 for various delivery vehicles, e.g. a syringe, for the controlled delivery of fluid through the catheter.

The main constituents of the catheter adapter are the rear body 76, the front body 78 and the holding hub 80. The rear body 78 has a central flange 82. From the rear face 84 of the central flange 82 extends a connection cylinder 86 having a threaded outer surface 88 and a hollow central bore 90. The function of this cylinder is to facilitate luer attachment of apparatus for controlled delivery of fluid to the catheter assembly 54. The end cap 92 provided with the catheter adapter 74 is primarily for sterility purposes, and is simply removed after the catheter adapter 74 is attached to the catheter assembly 54. The central flange has, at its center, a bore 93 passing completely therethrough such that the rear face 84 and front face 94 are in fluid communication.

From the front face 94 of the central flange 84 extends an operating cylinder 96. Where the operating cylinder 96 is connected to the front face 94 of the central flange 84, it is of a certain diameter 95. Along the length of the operating cylinder, the diameter of the operating cylinder is reduced by a taper 98. The remainder of the operating cylinder is of this reduced diameter 99 to the distal end 100 of the operating cylinder. The operating cylinder 96 has a central bore 102 which extends along the entire length thereof. Axial slots 104 extend from the distal end 100 of the operating cylinder, nearly the length thereof, i.e. the slot ends 106 extend nearly to the juncture of the operating cylinder 96 and the front face 94 of the central flange 82. Contained in and extending most of the length of the central bore 102 of the operating cylinder 96 is an elongated rubber gasket 105.

The front body 78 of the catheter adapter has a structure similar in geometry to the central flange 84 of the rear body 76, this structure is called the rear flange 110. The rear flange 110 has extending from the front face 112 thereof a front cylinder 114. The front cylinder 114 has an essentially constant outside diameter extending from the front face 112 of the rear flange 110 to the distal end 116 of the front cylinder. A central bore 118 is provided in the front cylinder 114, extending the entire length thereof. This central bore 118 has several different diameter changes along its length. At the entry portion of the central bore 120 on the rear face 122 of the rear flange, the diameter of the bore is slightly larger that the diameter 95 of the operating cylinder 96 where it is connected to the front face 94 of the central flange 84. Along the length of the central bore 120 the inside diameter is reduced by a taper 123 which is a mirror image of taper 98 on the operating cylinder. These mirror image structures thus allow sliding contact between the outer surface of the operating cylinder 96 and the central bore 120 of the front body 78.

The holding hub 80 is a generally tubular body provided with a cylindrical recess 126 formed in the rear face 128 thereof. The distal end 100 of the operating cylinder 96 is matingly engageable with the cylindrical recess 128 of the holding hub 80 and is rigidly attached thereto. The diameter of the central bore 120 of the front body 78 is, from the front face thereof 94 to a depth less than the length of the holding hub, slightly greater than the diameter of the holding hub. The rigid connection between the holding hub 80 and the distal end 100 of the operating cylinder holds these two structures in slidable relationship with the front body 78.

In use, the catheter adapter 74 is initially in the configuration shown in FIG. 4. In this configuration the proximal end 60 of the catheter assembly 54 may be freely inserted and withdrawn from the catheter adapter. The proximal end 60 of the catheter assembly 54 may be held in place by sliding the front body 78 toward the rear body 76 of the catheter adapter. In sliding these pieces relative to each other, the taper 98 of the operating cylinder 96 will be compressed by the taper 123 of the interior of the front body. The slots 104 in the operating cylinder 96 allow this compression to occur. The compression of the operating cylinder results in the compression of the elongated rubber gasket 105. This compression of the elongated rubber gasket 105 results in the rubber gasket frictionally engaging the proximal end 60 of the catheter assembly 54 such that the catheter may not be easily removed from the catheter adapter.

An additional structure of this embodiment of the catheter adapter which is of interest is the metal washer 130. This metal washer 130 is disposed about the operating cylinder 96 adjacent the front face 94 of the central flange 82. Seal 132 prevents leakage of fluid adjacent the metal washer 130. The metal washer 130 is provided with a tab portion 134 which extends above the flange portions 84 and 110. This allows electrical contact to be made to the washer by way of the same electrical connector 52 as was used previously to conduct electricity into the needle assembly 16 from an anaesthetic nerve stimulator 17. As can be seen in FIGS. 5 and 6, a pair of wires 138 are attached to the metal washer 130 and extend from the metal washer to the internal bore 140 of the elongated rubber gasket 105. Thus, when the elongated rubber gasket 105 is compressed about the proximal end 60 of the catheter assembly 54, electrical contact is made between the pair of wires 138 and the helical wire 58. As a result, electrical contact may be made from the anaesthetic nerve stimulator 17, through the catheter adapter 74 and into the helical wire 58 of the catheter apparatus 54 and, thus, to the conductive distal tip 72 of the catheter assembly. For the embodiment where a thin layer of insulating material is disposed about the conducting portions of the assembly, removal of the insulating material at the portions which will come in contact with wires 138 is necessary. Wires 138 may also be adapted to allow electrically contact ribbon wire 57, thus allowing electrical stimulator 17 to be attachable to ribbon wire 57 through the catheter adapter 74.

In an alternate embodiment of the apparatus to be used to deliver an anaesthetic drug, several changes regarding the conduction of electricity from a voltage source, e.g. nerve stimulator 17, to the proper point inside the patient are made. This alternative embodiment allows a medical practitioner to utilize the instruments more easily, with more precision and with fewer steps as well as fewer apparatus elements to keep track of. The embodiment is described below. However, many of the elements discussed with regard to the alternate embodiment are easily interchangeable with and can be used in conjunction with other embodiments. To the extent that an element from the earlier embodiment was described above and is retained in a similar form in the following alternate embodiment, the same numbering shall be used to identify that element.

Referring first to FIG. 22, there is shown relevant portions of a human body 10 containing a nerve 12 located subcutaneous to a skin surface portion 14. A needle assembly 16 has been inserted into a specific point in the skin surface portion 14 of the human body 10 for the purpose of locating a nerve 12. The needle assembly 16 comprises a needle 18 and a central stylet 20 which extend coaxially of one another. The needle 18 is a metal needle which is joined at its rear end to a hub 22 of a plastic material. The needle 18 is hollow and projects forwardly of the hub 22.

The needle 18 has three portions along its length. The major portion of the needle is the central portion 24 thereof. This central portion 24 of the needle is wrapped on the outside surface thereof with an insulating coating 26 which will not conduct electricity. This coating 26 is shown in FIG. 22 as being divided into sections of alternating color 28 and 30. Each of these sections is of a known, specific, length. Such colored sectioning enables the user to determine the extent of penetration of the tip 32 of the needle 18.

The remaining two portions of the needle 18 are the distal end 34 and the proximal end 36. At its proximal end 36, the needle 18 extends within the hub 22 where it is secured, such as by molding the hub around the needle. In this embodiment the proximal end 36 of the needle 18 extending outside of the hub 22 is covered with insulating coating 26. The bore extending through the needle 38 opens into an axially-aligned bore 40 extending through the hub 22 having the same diameter as the needle bore 38. The rear end of the bore 40 is enlarged and tapered to provide a female Luer opening 44 for use in receiving the stylet 20 and stylet hub 21. A connection wire 144 is provided which extends through the hub 22 and is electrically connected within the hub to the needle 38. The hub 22 being an insulating material and the connection wire 144 external to the hub 22 being insulated, the leakage of voltage from the connection wire 144 is prevented. A connection plug 142 is provided on the external end of the connection wire 144. This connection plug 142 allows the connection wire 144 to be easily connected to a nerve stimulator apparatus 17.

The distal end 34 of the needle is not covered by any electrically insulating material and is in electrical contact, by way of the covered central portion 24, with the portion of the needle which is connected to the connection wire 144. The insulating coating 26 prevents the flow of electricity radially out of the central portion 24 and proximal portion 36 of the needle, but allows the flow of electricity axially along the length of the needle 18.

The inner stylet 20 is of the same construction as described with respect to FIGS. 1 and 1D.

Referring next to FIG. 9, there is shown a catheter assembly 54 in combination with other elements of this embodiment. The catheter assembly 54 is essentially the same as described previously and of a diameter which allows the assembly to be inserted through the needle assembly 16 and into the body of the patient. The catheter comprises a sheath 56 formed from a thermoplastic or similar material. The helical wire 58 and sheath 56 define a central bore 66 through which a liquid may freely pass.

As in the earlier embodiment, the proximal portion 60 of helical wire 58 is left exposed so that it may be electrically contacted. The connection hub 174 of the embodiment shown in FIG. 9 is able to frictionally engage the proximal end of the catheter 54 especially the portion of the catheter sheath 56 adjacent the proximal end 60 of the helical wire. The connection hub 174 slidably receives and frictionally holds the proximal end of the catheter 56. The electrical connector 176 is formed from a conductive material and acts as a physical and electrical connector between the electrical cable 172 and the catheter stylet 178 which in turn is electrically in contact with much of the length of the helical coil 60 and the safety ribbon wire 57. The electrical connector 176 is completely surrounded and rigidly held by the connection hub 174, which is made of an insulating material. Insulated connection wire 172 is also rigidly connected to the electrical connector 176 at connection point 180. Thus, the connection wire 172 allows an electrical voltage to be conducted from the connection plug 170 to the electrical connector 176 and the helical wire 58. The connection plug is dimensioned so as to be able to be connected to a voltage source such as the nerve stimulator 17 (FIG. 1).

The proximal end of central stylet 178 is rigidly connected to electrical connector 176 at point 182 and extends, when the catheter is frictionally retained by the connection hub 174, through the central bore 66 of the catheter 54 for the majority of the length of the catheter 54. Stylet distal end 179 is shown in FIG. 9. The central stylet is a long wire structure which is of such a material so as to provide extra rigidity to the catheter during the time when such rigidity is needed, i.e. prior to and during insertion of the catheter 54.

Note in FIG. 9 that, because the catheter 54 is retained in the connection hub 174, central stylet 178 and ribbon wire 57 are both present in the catheter lumen 66. Central stylet 178 extends from where it attaches to electrical connector 176 at point 182 to its distal end 179 not rigidly attached to any other structure. Ribbon wire 57, as described above, has a distal end rigidly connected to distal tip 72 and a proximal end rigidly connected to the proximal end 60 of the catheter assembly 54.

As in the earlier described embodiment, the distal portion 64 of the helical wire 58 is short relative to the remainder of the catheter assembly 54 and not covered by the catheter sheath 56. Attached to the distal end of the catheter 54 is conductive distal tip 72 which is a piece of rounded metal. Conductive distal tip 72 is electrically contacted to the nerve stimulator through the intervening structures, whether through the wire coil 58 or the ribbon wire 57.

Referring next to FIGS. 7 and 8, there is shown a catheter adapter 74. Accessing the central bore 66 of the catheter assembly 54 would be difficult given the diameter of this structure. Th