Dual mode transurethral microwave warming apparatus

• US 6,424,869 B1
• Filed: 01/03/2000
• Issued: 07/23/2002
• Est. Priority Date: 09/06/1995
• Status: Expired due to Term

• Current Assignee: Coral Sand Beach, LLC
• Original Assignee: Meridian Medical Systems LLC
• Inventors: Carr, Kenneth L., Regan, James F.
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/476,201
• Time in Patent Office: 932 Days
• Field of Search: 604/113-114, 604/22, 128/736, 607/101, 607/156, 607/102, 607/113, 606/27-31
• US Class Current: 607/101
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/1861 with an instrument inserted into a body lumen or cavity, e.g. a catheter
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61M 1/0281 Apparatus for treatment of blood or blood constituents prior to transfusion, e.g. washing, filtering or thawing
• CPC Class Codes: A61M 1/369 Temperature treatment
• CPC Class Codes: A61M 2205/3686 microwaves
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media
• CPC Class Codes: H05B 6/802 for heating fluids methods of heating fluids in conventional microwave ovens H05B6/687

Abstract

A dual mode transurethral warming apparatus particularly adapted to treat benign prostatic hyperplasia includes a urethral catheter dimensioned for insertia through the urethra. The catheter includes an elongated flexible tube having a plurality of longitudinal lumens extending between the ends of the tube. A coaxial cable extends along one of the lumens to an antenna in the form of a multi-turn helical winding wound around the outside of the tube. A first connector connects one of the cable conductors to one end of the winding and a second connector connects the other cable conductor to the other end of the winding so that the antenna formed by the winding is larger in diameter than the cable, and all of the lumens are located within the winding. The cable is connected to a control and display unit which includes a transmitter which provides electromagnetic energy via the cable to the antenna so that the antenna generates an electromagnetic field sufficient to treat tissue adjacent the antenna. The same antenna also detects thermal energy emitted by the tissue thereby developing an electrical signal which is fed via the cable to a receiver in the form of a radiometer in the control and display unit. The cable is connected to the transmitter and receiver by way of a diplexer which separates the transmitter and receiver signal frequencies allowing the use of the common coaxial cable and antenna for both heating the tissue and sensing the actual temperature of the tissue. Preferably, the catheter includes an inflatable balloon at the distal end of the tube, the balloon being inflated by flowing an inflation fluid to the balloon via one of the lumens in the tube. Other working lumens may be included in the tube for providing drainage and for coolant circulation to cool the exterior surfaces of the catheter.

Claims

1. Transurethral warning apparatus comprising

a urethral catheter dimensioned for insertion through the urethra, said catheter including an elongated flexible tube having a proximal end, a distal end and a plurality of longitudinal lumens extending between said ends;

a cable extending along one of said lumens, said cable having at least two conductors;

an antenna in the form of a multi-turn helical winding wound around the outside of said tube, said winding having a proximal end and a distal end;

a first electrical connection extending from one of the conductors through the tube to the proximal end of the winding;

a second electrical connector extending from the other of said conductors through the tube to the distal end of the winding whereby said antenna is larger in diameter than said cable and all of said lumens are contained within said winding, and

means for delivering electromagnetic energy to said cable so that the antenna generates an electromagnetic field sufficient to heat tissue in the vicinity of said antenna, said delivering means including a transmitter for transmitting a first signal of a first frequency capable of heating tissue;

a receiver for receiving a second signal of a second frequency indicative of thermal radiation, said receiver producing an output signal in response thereto, and

a diplexer connecting the proximal end of the cable to the transmitter and receiver, said diplexer coupling said first signal from the transmitter only to said antenna while coupling said second signal from said antenna only to said receiver so that the apparatus can simultaneously heat tissue and determine the actual temperature of the tissue in the vicinity of said antenna.

2. The apparatus defined in claim 1 and further including

an annular inflatable balloon encircling said tube between the winding and the distal end of the tube;

a side port in the tube having one end communicating with the interior of the balloon and a second end communicating with a second one of said plurality of lumens, and

means for delivering an inflation fluid to said second lumen.

3. The apparatus defined in claim 2 and further including a sleeve snugly covering over said winding.

4. The apparatus defined in claim 3

wherein said balloon and sleeve are constituted by a single length of elastic tubing, and

further including means for sealing the sleeve to the tube between the antenna and the side port and the between the side port and the distal end of the tube so as to define the confines of the balloon.

5. The apparatus defined in claim 2

wherein a third one of said plurality of said lumens extends the entire length of the catheter, and

further including means for drawing a vacuum in said third lumen.

6. The apparatus defined in claim 1 and further including

means for connecting a selected couple of said plurality of lumens, other than said one lumen, at the distal end of the tube to form a lumen loop in the tube, and

means for circulating a coolant along said lumen loop.

7. The apparatus defined in claim 1 wherein said diplexer comprises

a first arm connected between the transmitter and the antenna and containing a low-pass filter which passes only said first signal, and

a second arm connected between the receiver and a junction between the low pass filter and the antenna, said second arm containing a band pass filter which passes said second signal but blocks said first signal.

8. The apparatus defined in claim 1 wherein the frequency of the second signal is much higher than the frequency of the first signal.

9. The apparatus defined in claim 8 wherein the receiver comprises a radiometer.

10. The apparatus defined in claim 9 wherein said catheter also includes expandable means located adjacent to said antenna, said expandable means being movable between a contracted position wherein the expandable means lies substantially within the cross sectional envelope of the catheter and an expanded position wherein the expandable means extend outside said envelope, and

means in said tube for moving the expandable means between said positions.

11. The apparatus defined in claim 1 and further including a display responsive to said output signal for producing an indication of the actual temperature of the tissue.

12. The apparatus defined in claim 11 and further including control means responsive to said output signal for controlling the transmitter to heat tissue according to a selected temperature/time profile.