Method and apparatus for determining the position of catheters, tubes, placement guidewires and implantable ports within biological tissue

• US 5,375,596 A
• Filed: 09/29/1972
• Issued: 12/27/1994
• Est. Priority Date: 09/29/1992
• Status: Expired due to Term

• Current Assignee: Neo Medical, Inc.
• Original Assignee: HDC Corporation
• Inventors: Twiss, Robert G., Ryder, Marcia A.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): GILBERT, SAMUEL G
• Application Number:
  US07/953,072
• Time in Patent Office: 8,124 Days
• Field of Search: 128/898, 128/899, 128/903, 128/653.1, 604/53, 604/264, 604/280, 604/93, 604/95, 604/100, 340/853.8, 607/154, 607/156
• US Class Current: 600/424
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A method and apparatus for determining accurately, both during and after insertion, the full length position of catheters (including implanted ports (64)), tubes (30) and placement guidewires (22) within biological tissue is disclosed including a transmitter/detector unit (2) having an alternating current (AC) radio-frequency (RF) transmitter with antenna (14), and a radio signal transmitter in the form of a continuous or segmented fine wire receiving antenna (28, 32, 74) situated along the full length of the catheter, guidewire, and implanted port assemblies (22, 30, 64). The guidewire apparatus also includes a tip antenna. These antennae are connected by a removable clip (18) to a wide-band RF detector circuit, situated within the transmitter/detector unit (2). The RF transmitter/detector circuit provides a voltage output that is a direct function of the relative spatial proximity of the transmitting antenna. This proximity is displayed visually to the operator using a sequential linear LED array (8) whose sensitivity is controlled by a gain control knob (10). An audible tone is also produced by a miniature speaker (12), and whose tone frequency is varied as a direct function of the transmitter proximity. Also shown is a method and apparatus for locating the full length position of implanted port (64) mounted catheters (72), and a method and apparatus for simultaneous infusion into an implanted port assembly 64 and detecting the full length position of the port mounted catheter (72).

Claims

1. A system for assisting in the placement and location of previously inserted catheters, tubes or placement guidewires inside biological tissue, wherein each of said catheters, tubes or placement guidewires have a proximate end and a distal end and a predefined first length therebetween, said system being able to determine a location of said catheters, tubes or placement guidewires inside biological tissue in close proximity thereto at any point anywhere along the first length thereof, said system comprising in combination:

at least one of a catheter, tube or placement guidewire each being formed of a flexible solid material of a measurable thickness along the predefined first length thereof having;

a first antenna being a flexible dipole having a proximate and a distal end defining a selected second length therebetween contained individually within said flexible solid material of each of said at least one of a catheter, tube or placement guidewire with the proximate ends of said flexible solid material and said first antenna in alignment, with said first antenna extending along at least a portion of the length of each of said at least one catheter, tube or placement guidewire to receive or transmit an RF signal along the selected second length of the flexible dipole; and

a first connector mounted on said proximate end of each of said at least one of a catheter, tube or placement guidewire and connected to said proximate end of said first antenna with the distal end of said first antenna being otherwise free of connection; and

a detector/transmitter including;

a second antenna to receive or transmit an RF signal between itself and said first antenna external to said biological tissue in which each of said at least one of a catheter, tube or placement guidewire is located;

an RF transmitter to generate an RF signal;

a first conductor connected to apply said RF signal from said RF transmitter to one of said first and second antennas;

a detector to determine the strength of said RF signal being coupled electro-magnetically between said first and second antennas as said second antenna of said transmitter/detector is brought into proximity of said first antenna within each of said at least one of a catheter, tube or placement guidewire in place within said biological tissue;

a signaling device coupled to said detector to provide an indication to the user of a strength of said RF signal coupled between said first and second antennas; and

a second connector disposed to couple with said first connector to couple said RF signal between said first antenna and said detector/transmitter.

2. The system as in claim 1 wherein said signaling device includes a visual display to provide an indication of the strength of said RF signal as a function of the proximity between said first and second antennas.

3. The system as in claim 1 wherein said signaling device includes an enunciator to generate a signal audible to the user that increases or decreases in volume or frequency as the strength of said RF signal increases or decreases, respectively, as a function of the proximity between said first and second antennas.

4. The system as in claim 1 wherein said detector/transmitter includes a housing outward from which extends said second antenna with said second antenna having a selected shape.

6. The system as in claim 2 wherein said placement guidewire further includes a third antenna being a flexible dipole having a proximate end and a distal end defining a second length therebetween contained individually within said flexible solid material of said placement guidewire with said third antenna extending along at least a portion of the first length of said placement guidewire to receive or transmit an RF signal.

7. The system as in claim 2 wherein said detector/transmitter includes a housing outward from which extends said second antenna with said second antenna having a selected shape.

5. A system for assisting in the placement and location of a previously inserted placement guidewire inside biological tissue, wherein said placement guidewire has a proximate end and a distal end and a predefined first length therebetween, said system being able to determine a location of a selected point along the length of said placement guidewire inside biological tissue in close proximity thereof, said system comprising in combination:

a placement guidewire being formed of a flexible solid material and being of a measurable thickness along the predefined first length thereof, said placement guidewire having;

a first antenna contained within said flexible solid material of said placement guidewire including;

a conductive mass located at a selected point along the length of said placement guidewire to receive or transmit an RF signal;

a first coaxial cable having an outer shield and a central conductor with only said central conductor being connected to said conductive mass, and said first coaxial cable extending from said selected point to said proximate end of said placement guidewire;

a first connector mounted on said proximate end of said placement guidewire and thereat individually connected to each of said outer shield and central conductor at the proximate end of said first coaxial cable with said conductive mass being otherwise free of connection; and

detector/transmitter including;

a second antenna to couple an RF signal between itself and said first antenna external to said biological tissue in which said placement guidewire is located;

an RF transmitter to generate an RF signal;

a first conductor connected to apply said RF signal from said RF transmitter to one of said first connector and said second antenna;

a detector connecting to the one of said first connector and said second antenna to which said first conductor is not connected to determine a strength of said RF signal being coupled electro-magnetically between said first and second antennas as said second antenna of said transmitter/detector is brought into proximity of said first antenna within said placement guidewire in place within said biological tissue;

a signaling device coupled to said detector to provide an indication to the user of the signal strength of said RF signal coupled between said first and second antennas; and

a second connector connected to said detector to couple said detector to the one of said first connector and said second antenna to which said first conductor is not connected to conduct said RF signal by electro-magnetic radiation between said first antenna and said detector/transmitter.

8. A method for determining the path of a catheter or a placement guidewire in a catheter-placement guidewire system having a catheter and a placement guidewire, and a detector/transmitter, wherein:

each of said catheter and placement guidewire are each formed from a flexible solid material and each has a proximate end and a distal end with a predefined first length therebetween, in addition each of said catheter and placement guidewire has a first antenna being a flexible dipole having a proximate and a distal end defining a selected second length therebetween contained individually within said flexible solid material with said first antenna extending along at least a portion of the first length of each of said catheter and placement guidewire to receive or transmit an RF signal along the selected second length of the flexible dipole with a first connector mounted on said proximate end of each of said catheter and placement guidewire that is also connected to said proximate end of said flexible dipole with the distal end of said flexible dipole being otherwise free of connection in each of said catheter and placement guidewire; and

a detector/transmitter that includes an RF transmitter, a second connector disposed to couple with said first connector of said first antenna of one of said catheter and placement guidewire to couple said RF signal between that first antenna and said detector/transmitter, a second antenna to receive or transmit an RF signal between itself and said first antenna coupled to said second connector external to said biological tissue in which each of said catheter and placement guidewire are located, a first conductor connected to apply an RF signal from said RF transmitter to one of said first antenna coupled to said second connector and said second antenna, a detector to determine a strength of said RF signal being coupled electro-magnetically between said first antenna coupled to said second connector and said second antenna as said second antenna of said transmitter/detector is brought into proximity of said first antenna within each of said catheter and placement guidewire in place within said biological tissue, and a signaling device coupled to said detector to provide an indication to the user of the strength of said RF signal coupled between said first antenna coupled to said second connector and said second antenna, said method for determining a path of said first antenna of either of said catheter or placement guidewire, anywhere along the second length of said flexible dipole of said first antenna coupled to said second connector inside biological tissue comprising the steps of;

(a) at least partially inserting at least one of either of said catheter and placement guidewire into said biological tissue along a path that is believed to be a desired path;

(b) connecting said first connector of one of said catheter or placement guidewire of step (a) to said second connector of said transmitter/detector;

(c) coupling an RF signal between said second antenna of said transmitter/detector outside of said biological tissue and anywhere along the selected second length of said first antenna of the catheter or placement guidewire of step (a) having the first connector to which the second connector was connected in step (c);

(d) providing relative movement between said second antenna coupled to said second connector and said first antenna as in step (c) in the expected vicinity of the path within said biological tissue taken by said catheter or placement guidewire of step (c); and

(e) monitoring the indications of said signalling device to note those points where those indications reach a peak signal strength and noting the physical position of said second antenna relative to an outer surface of said biological tissue as in step (d) is performed; and

(f) repeating steps (a)-(e) until as much of the path of said first antenna coupled to said second connector as in step (b) is noted as desired to the extent to which said catheter or placement guidewire has been inserted in step (a).

9. A method as in claim 8 for locating the distal end of said catheter and placement guidewire wherein each of said catheter and placement guidewire includes a third antenna being a conductive mass located within said flexible solid material at a selected point along the length of said placement guidewire to receive or transmit an RF signal and said catheter longitudinally defines an internal bore therein, a first coaxial cable having an outer shield and a central conductor with only said central conductor being connected to said conductive mass and extending from said selected point to said proximate end of said placement guidewire, and at the proximate end of said coaxial cable with said central conductor and shield thereof individually connected to said first connector on the proximate end of said placement guidewire with said conductive mass being otherwise free of connection, said method further includes the steps of:

(g) following step (f), uncoupling said second connector from said first connector;

(h) following step (g), inserting said placement guidewire having said conductive mass therein into the internal bore of the catheter with the distal end of said catheter substantially corresponding with the distal end of said placement guidewire;

(i) following step (h), coupling said second connector of said transmitter/detector to said first connector of said placement guidewire;

(j) following step (i), repeating steps (c) and (d);

(k) monitoring the indications of said signalling device to note the point where those indications reach a peak signal strength and noting the physical position of said second antenna relative to an outer surface of said biological tissue as step (d) is performed thus locating the position of said conductive mass while said placement guidewire remains within said catheter as defined above.

10. A combination of a placement guidewire and a catheter for insertion into biological tissue, said catheter having an internal bore sized and shaped to slip over said placement guidewire before or after said placement guidewire has been inserted into said biological tissue, said placement guidewire comprising:

an elongated flexible portion having a distal end and a proximate end defining therebetween a first selected length, said flexible portion being formed of a flexible solid material with a substantially uniform selected cross-sectional shape and size along said first selected length thereof, said first selected length being at least as long as said internal bore of said catheter to be slid thereover and said cross-sectional size and shape of said flexible portion being smaller than the size and shape of the internal bore of said catheter;

an antenna being a flexible dipole having a proximate end and a distal end defining a second selected length therebetween contained within said flexible solid material of said flexible portion and extending along at least a portion of the first selected length of said flexible portion with said proximate ends of said flexible dipole and said flexible solid material being aligned with each other and said flexible dipole disposed to receive or transmit an RF signal along said second selected length of said flexible dipole; and

a connector having a third selected length and a cross-sectional shape and size over which a catheter, of a fourth selected length and having a proximate and a distal end, may be placed and advanced along said flexible portion and said connector is affixed to said proximate end of said flexible portion and connected to said proximate end of said flexible dipole with the distal end of said flexible dipole being otherwise free of connection wherein a combination of said first and third selected lengths is greater than said fourth selected length of said catheter, said connector being provided to permit connection to said proximate end of said flexible dipole external to said catheter when in place and when the distal ends of said catheter and said flexible portion are substantially in alignment with said connector then being external to said proximate end of said catheter.

11. A placement guidewire as in claim 10 wherein:

said flexible portion of said placement guidewire includes;

an indicator mark on said flexible portion near the proximate end of said flexible portion that when said catheter is in place and said indicator mark is aligned with the proximate end of said catheter the distal ends of said flexible portion and said catheter are substantial aligned with each other; and

said placement guidewire further includes;

a conductive mass located within said flexible solid material of said placement guidewire at a selected point along said first selected length of said flexible portion to receive or transmit an RF signal; and

a coaxial cable having an outer shield and a central conductor and a proximate end and a distal end with only said central conductor at the distal end of said coaxial cable being connected to said conductive mass and said proximate end of said coaxial cable being substantially aligned with the proximate end of said flexible portion, and at the proximate end of said coaxial cable, said central conductor and outer shield thereof are individually connected to said connector on the proximate end of said flexible portion with said conductive mass being otherwise free of connection, wherein when said conductive mass is located substantially at the distal end of said placement guidewire said conductive mass can be used to locate the distal end of said flexible portion and the distal end of said catheter when said catheter is in place and said indicator mark on said flexible portion is aligned with the proximate end of said catheter.

12. A combination of a placement guidewire and a catheter for insertion into biological tissue, said catheter having an internal bore sized and shaped to accept said placement guidewire therewithin, said placement guidewire comprising:

an elongated flexible portion having a distal end and a proximate end defining therebetween a first selected length, said flexible portion being formed of a flexible solid material with a substantially uniform selected cross-sectional shape and size along said first selected length thereof, said first selected length being at least as long as said internal bore of said catheter to be slid thereinto and said cross-sectional size and shape of said flexible portion being smaller than the size and shape of the internal bore of said catheter;

a flexible antenna being a flexible dipole having a proximate end and a distal end defining a second selected length therebetween contained within said flexible solid material of said flexible portion and extending along at least a portion of the first selected length of said flexible portion with said proximate ends of said flexible dipole and said flexible solid material being aligned with each other, and said flexible dipole disposed to receive or transmit an RF signal along said second selected length of said flexible dipole; and

a connector affixed to said proximate end of said flexible portion and connected to said proximate end of said flexible dipole with the distal end of said flexible dipole being otherwise free of connection, said connector having substantially the same cross-sectional shape and size as said flexible portion being provided to permit connection to said proximate end of said flexible dipole.

13. A placement guidewire as in claim 12:

said placement guidewire further including;

a conductive mass contained within said flexible solid material of said flexible portion at a selected location along the first selected length of said flexible portion to receive or transmit an RF signal; and

a coaxial cable contained within said flexible solid material of said flexible portion, said coaxial cable having an outer shield and a central conductor with only said central conductor being connected to said conductive mass and said coaxial cable extending from said conductive mass to said proximate end of said flexible portion; and

wherein said connector also is connected to each of said outer shield and central conductor of said coaxial cable at the proximate end of said flexible portion with said conductive mass being otherwise free of connection, said connector being provided to also permit individual connection to said outer shield and central conductor of said coaxial cable external to the biological tissue into which said placement guidewire is inserted.

14. A catheter for insertion within biological tissue for internal delivery of fluids from an external source of same, said catheter comprising:

a tube portion formed of a flexible solid material, said tube of a first selected length and diameter having a proximate end and a distal end and defining a longitudinal hole therethrough;

an antenna being a flexible dipole having a proximate end and a distal end defining a second selected length therebetween contained within said flexible solid material of said tube extending along at least a portion of the first selected length of said tube portion with said proximate ends of said flexible dipole and said tube portion in alignment, said flexible dipole to receive or transmit an RF signal along the second selected length of said antenna; and

a connector affixed to said proximate end of said tube portion, said connector defining a hole therethrough aligned with said longitudinal hole defined by said tube portion and connected to said proximate end of said antenna with the distal end of said antenna being otherwise free of connection, said connector being provided to permit connection to said antenna external to the biological tissue into which said catheter is inserted, as well as connection to said external source of fluids for internal delivery.

15. An implantable port/catheter assembly for insertion within tissue for internal delivery of fluids from an external source of same, said implantable port/catheter assembly comprising:

a catheter including;

a flexible tube portion of a selected outer diameter having a proximate end and a distal end defining a first selected length therebetween, and at least one of a centrally located longitudinal hole therethrough and a cavity extending thereinto with an exit port therefrom; and

a flexible dipole having a distal end and a proximate end defining a second selected length therebetween with said proximate ends of said flexible tube portion and said flexible dipole in alignment and with said flexible dipole extending along at least a portion of the length of said flexible tube portion from said proximate end thereof to receive or transmit an RF signal therealong;

an implantable port including;

a well defining a blind internal cavity therewithin to receive infused liquids, said internal cavity defining a top opening and interior side and bottom surfaces thereof, said internal cavity including therewithin;

a conductive layer lining at least a portion of the bottom surface of said cavity;

a pierceable sealant layer enclosing said conductive layer to prevent said infused liquids from reaching said conductive layer;

a port above said sealant layer and extending through the side surface of said internal cavity to communicate with said proximate end of said flexible tube portion of said catheter to provide said infused liquid to said catheter; and

a wire extending from said conductive material layer into said port;

a pierceable dome to enclose the top opening of said cavity of said well to prevent body fluids from entering said internal cavity of said well; and

a coupler interconnecting the proximate end of the flexible tube portion of said catheter with said port to deliver infused liquids from said well to said catheter and to connect said proximate end of said flexible dipole of said catheter to said wire of said well with the distal end of said flexible dipole being otherwise free of connection.

16. An implantable port/catheter assembly as in claim 15 further including:

a non-invasive external transmitter/detector to radiate an RF signal, and to detect and determine a strength of said RF signal as received by said flexible dipole of said catheter; and

a port access needle having;

a conductive core having a proximate and a distal end with a sharpened conductive tip at the distal end thereof;

an insulative outer layer around said core leaving only a portion of said tip exposed; and

a connector at the proximate end of said core disposed to be connected to said external transmitter/detector to couple the signal received by said flexible dipole thereto when the tip of said port access needle has been inserted thorough said dome and said sealant layer into said conductive material layer to make contact therewith by said tip of said port access needle to complete a connection with said flexible dipole of said catheter to make it possible to locate said port/catheter assembly when liquids are not being infused thereinto.

17. An implantable port/catheter assembly as in claim 15 further including:

a non-invasive external transmitter/detector to radiate an RF signal and to detect and determine a strength of said RF signal as received by said flexible dipole of said catheter; and

an infusion needle assembly having;

a needle body having;

a conductive core of an elongated shape with an exterior side surface and a proximate and a distal end with a sharpened tip at the distal end thereof, and said core defines therewithin a longitudinally extending interior cavity that opens to the proximate end of said core and to the side surface of said conductive core intermediate said proximate and distal ends thereof;

an insulative coating in said cavity and on substantially all of said external side surface of said core leaving only a portion of said tip at the distal end thereof exposed; and

a coupler connected to said core at the proximate end thereof disposed to be connected to said external transmitter/detector to couple the signal received by said antenna thereto when the uncoated distal tip of said needle body has been inserted thorough said dome and said sealant layer into said conductive material layer to make contact therewith by said tip of said needle body to complete a connection with said antenna of said catheter to make it possible to locate said port/catheter assembly;

said opening in the side surface of said conductive core disposed to be above said sealant layer when said needle body has been inserted thorough said dome and said sealant layer into said conductive material layer; and

a fluid tube assembly having;

a hollow tube with a distal end and a proximate end for conducting fluid to be infused from said external source at the proximate end to said needle body at the distal end;

a first connector at said proximate end of said tube disposed to mate with said external source of said fluid to be infused;

a second connector at said distal end of said tube disposed to deliver said fluid for infusion into said cavity within said conductive core of said needle body and disposed to make connection with said conductive core of said needle body;

a third connector disposed to be connected to said external transmitter/detector; and

a conductor to interconnect said third connector and said second connector to each other.