Catheters for treating prostate disease

• US 5,007,437 A
• Filed: 04/19/1990
• Issued: 04/16/1991
• Est. Priority Date: 06/16/1989
• Status: Expired due to Term

• Current Assignee: MMTC Limited (Government of India)
• Original Assignee: MMTC Limited (Government of India)
• Inventors: Sterzer, Fred
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/512,520
• Time in Patent Office: 362 Days
• Field of Search: 128/784, 128/786, 128/788, 128/804, 128/401
• US Class Current: 607/138
• 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 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/22069 Immobilising; Stabilising
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: A61M 25/1002 characterised by balloon shape A61M25/1006, A61M25/1009 take precedence
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

Applying squeezing pressure to a diseased prostate, by means of a urethral and/or rectal catheter incorporating an inflatable prostate balloon, to compress the prostate while it is being irradiated from a microwave antenna, increases the therapeutic temperature to which the prostate tissue more distal to the microwave antenna can be heated without heating any non-prostate tissue beyond a maximum safe temperature, and reduces the temperature differential between the heated more distal and more proximate prostate tissue from the microwave antenna.

Claims

1. In a catheter adapted to be inserted into an orifice of a male patient for treating prostate disease, wherein said catheter comprises means including microwave antenna means for irradiating said patient'"'"'s prostate with a given distribution of microwave field intensity, thereby to heat tissue of said patient to a temperature which tends to vary as a direct function of microwave power and as an inverse function of the distance of that tissue to said microwave antenna means, and wherein the maximum microwave power to be employed is limited to an amount at which the temperature of the patient'"'"'s heated tissue most proximate to said microwave antenna means does not exceed a given safe maximum temperature;

the improvement wherein said catheter further comprises;

an inflatable balloon inside of which said microwave antenna means is situated, said balloon being structured to have a cross-section which is expandable in size from a first value no larger than the cross-section of said orifice when said balloon is deflated to a second value substantially larger than the cross-section of said orifice when said balloon is inflated to a given pressure, said given pressure being sufficient to squeeze and compress tissue of said patient adjacent said balloon and permit the size of said balloon cross-section to be expanded to its second value;

whereby said catheter may be (1) inserted into said orifice while in a deflated state and positioned therein at a location at which both said balloon and said microwave antenna means are in cooperative relationship with said patient'"'"'s prostate for effecting the irradiation of said patient'"'"'s prostate with said given distribution of microwave field intensity when said catheter is fully inserted into said orifice, and (2) said balloon may be inflated to said given pressure when said catheter is fully inserted for expanding the size of its cross-section to said second value, resulting in both prostate tissue and that non-prostate tissue situated between said inflated balloon and said prostate tissue being squeezed and compressed so as thereby to increase the minimum distance between said microwave antenna means situated inside of said balloon and heated tissue of said patient; and

means for inflating said balloon to said given pressure;

whereby the maximum microwave power may be increased without exceeding said given maximum safe temperature and the temperature differential between the heated prostate tissue more proximate to said microwave antenna means and the heated prostate tissue more distal to said microwave antenna means is reduced.

2. The catheter defined in claim 1, wherein said orifice is said patient'"'"'s urethra;

and wherein;

said catheter has a circumference about a central axis thereof;

said balloon, when inflated to said given pressure, forms a circumferentially symmetrical toroid that extends around the entire circumference of said catheter for applying substantially equal squeezing pressure to compress the surrounding prostate tissue, thereby effectively increasing the internal diameter of said prostate; and

said microwave antenna means is located substantially on the central axis of said catheter for applying a substantially angularly-uniform distribution of microwave field intensity to said prostate tissue.

3. The catheter defined in claim 2, wherein:

said catheter further comprises a second inflatable balloon disposed at an end of said catheter which is in cooperative relationship with the patient'"'"'s bladder when the catheter is fully inserted, for securing said catheter to said bladder when said second balloon is inflated, and a lumen having an opening at said end, which opening is situated within said patient'"'"'s bladder when the catheter is fully inserted, for permitting urine to be transported from said patient'"'"'s bladder through said lumen to the outside of said patient'"'"'s body.

4. The catheter defined in claim 3, wherein:

said catheter further comprises means including a second lumen for circulating a coolant for removing heat generated by said microwave power, whereby the maximum microwave power may be increased to heat the prostate tissue more distal from said microwave antenna means to a higher temperature without concurrently exceeding said given safe maximum temperature for the patient'"'"'s heated tissue most proximate to said microwave antenna means.

5. The catheter defined in claim 1, wherein said orifice is said patient'"'"'s rectum;

and wherein;

said means including said microwave antenna means comprises distribution means for providing a distribution of microwave field intensity that preferentially heats said patient'"'"'s tissue in a direction towards said patient'"'"'s prostate more than said patient'"'"'s tissue in a direction away from said patient'"'"'s prostate.

6. The catheter defined in claim 5, wherein:

said microwave antenna means is offset from the axis of said catheter in a direction adapted to be oriented toward said patient'"'"'s prostate when said catheter is fully inserted in said patient'"'"'s rectum.

7. The catheter defined in claim 5, wherein:

said microwave antenna means includes a reflector adapted to be oriented to provide said distribution of microwave field intensity when said catheter is fully inserted in said patient'"'"'s rectum.

8. The catheter defined in claim 5, wherein:

said microwave antenna means includes a phased array adapted to provide said distribution of microwave field intensity when said catheter is fully inserted in said patient'"'"'s rectum.

9. The catheter defined in claim 5, wherein:

said balloon has a given shape, said given shape being configured so that expansion of the cross-section of a fully-inserted balloon from said first to said second values thereof results in said balloon first substantially conforming to a bulge in the patient'"'"'s rectum caused by an enlarged prostate and then applying substantially equal squeezing pressure to said bulge for compressing said enlarged prostate.

10. The catheter defined in claim 5, wherein:

said catheter further comprises means including a second lumen for circulating a coolant for removing heat generated by said microwave power, whereby the maximum microwave power may be increased to heat the prostate tissue more distal from said microwave antenna means to a higher temperature without concurrently exceeding said given safe maximum temperature for the patient'"'"'s heated tissue most proximate to said microwave antenna means.

11. The catheter defined in claim 1, wherein:

said means for inflating said balloon comprises means for inflating said balloon with a radio-opaque liquid, whereby the position of said balloon with respect to said patient'"'"'s prostate can be monitored when said catheter is inserted in said patient'"'"'s orifice.

12. A method for treating prostate disease of a patient;

said method comprising the steps of;

applying sufficient squeezing pressure to non-prostate tissue which surrounds an orifice of the patient in the vicinity of the patient'"'"'s prostate both to compress the prostate and non-prostate tissue and to increase the distance from a given location within said orifice to said non-prostate tissue; and

while said pressure is being applied, irradiating said prostate through said non-prostate tissue from said given location within said orifice with microwave power sufficient to heat that prostate tissue which is more distal to said orifice to a first therapeutic temperature without heating any non-prostate tissue of the patient above a maximum safe temperature.

13. The method defined in claim 12, wherein:

the step of applying squeezing pressure comprises applying squeezing pressure to that non-prostate tissue which surrounds the patient'"'"'s urethra thereby to increase the diameter of said urethra; and

the step of irradiating said prostate includes the step of irradiating said prostate from said urethra.

14. The method defined in claim 13, further comprising the step of:

while said pressure is being applied to said tissue surrounding said patient'"'"'s urethra and said prostate is being irradiated with microwave power from said patient'"'"'s urethra, irradiating said patient'"'"'s prostate from a position outside of said patient'"'"'s urethra through second non-prostate tissue that is situated between said outside position and said prostate tissue with additional microwave power, said additional microwave power being sufficient to heat that prostate tissue which is more distal to said urethra and is situated between said patient'"'"'s urethra and said second non-prostate tissue to a second therapeutic temperature that is higher than said first therapeutic temperature without heating said second non-prostate tissue above a maximum safe temperature.

15. The method defined in claim 13, further comprising the steps of:

while said pressure is being applied to said tissue surrounding said patient'"'"'s urethra, applying additional squeezing pressure to tissue of the patient'"'"'s rectum in the vicinity of the patient'"'"'s prostate; and

while said prostate is being irradiated with microwave power from said patient'"'"'s urethra, irradiating said patient'"'"'s prostate from said patient'"'"'s rectum with additional microwave power sufficient to heat that prostate tissue which is more distal to said urethra and is situated between said patient'"'"'s urethra and rectum to a second therapeutic temperature that is higher than said first therapeutic temperature without heating non-prostate tissue proximate to said patient'"'"'s rectum above a maximum safe temperature.