Patent Application
20050021014
1. Field of the Invention
The present invention relates to urological warming and cooling devices and more particularly to a warming catheter and method of warming the urethra of a patient during ablative surgery.
2. Description of the Related Art
Cryosurgical probes are used to treat a variety of diseases. The cryosurgical probes quickly freeze diseased body tissue, causing the tissue to die after which it will be absorbed by the body, expelled by the body or sloughed off. Cryothermal treatment is currently used to treat prostate cancer and benign prostate disease, breast tumors and breast cancer, liver tumors and liver cancer, glaucoma and other eye diseases. Cryosurgery is also proposed for the treatment of a number of other diseases.
The use of cryosurgical probes for cryoablation of the prostate is described in, for example, Onik, Ultrasound-Guided Cryosurgery, Scientific American at 62 (January 1996). Cryosurgical probe systems are manufactured by present assignee, Endocare, Inc. of Irvine, Calif. In cryosurgical ablation procedures generally several cryosurgical probes are inserted through the skin in the perineal area (between the scrotum and the anus), which provides the easiest access to the prostate. The probes are pushed into the prostate gland through previously placed cannulas. Placement of the probes within the prostate gland is typically visualized with an ultrasound imaging probe placed in the rectum. The probes are quickly cooled to temperatures typically below −120° C. The prostate tissue is killed by the freezing, and any tumor or cancer within the prostate is also killed. The body absorbs some of the dead tissue over a period of several weeks. However, other necrosed tissue may slough off and pass through the urethra, often causing undesirable blockage. Thus, it is often desirable to avoid cryoinjury to the urethra during cryoablation of the prostate. This may be done by placing a warming catheter in the urethra and continuously flushing the catheter with warm fluid to keep the urethra from freezing.
Devices for warming the urethra have been available for quite some time. In 1911, U.S. Pat. No. 1,011,606 issued for an “Appliance For Subjecting Portions Of The Human System To Heat Or Cold.” This device was a coaxial dual lumen catheter intended for the application of therapeutic cooling or heating to the urethra and bladder. Devices for warming other body parts have also been proposed, such as U.S. Pat. No. 4,244,377, issued Jan. 13, 1981 to Grams entitled “Ear Probe For Use In Closed-Loop Caloric Irrigation”, which shows a coaxial dual lumen cannula intended for the application of therapeutic heating inside the ear.
U.S. Pat. No. 5,437,673, issued on Aug. 1, 1995 to Baust, et al., entitled “Closed Circulation Tissue Warming Apparatus and Method of Using the Same in Prostate Surgery” illustrate use of a urethral warming catheter which is used to protect the urethra from cryothermal damage during cryosurgical treatment of the prostate for benign prostate hyperplasia. The Baust patent discloses a coaxial three lumen catheter in which warm saline passes through an outside lumen and is returned through a coaxial second lumen. A third lumen is a urinary drainage lumen centrally disposed within the other two lumens. The catheter is used to heat the urethra while the prostate is being frozen with cryosurgical probes.
U.S. Pat. No. 5,257,977, issued on Nov. 2, 1993 to Eshel, entitled “Technique for Localized Thermal Treatment of Mammals,” shows a catheter that delivers heated saline flow to provide therapeutic hyperthermia treatment of the prostate. Like the Baust patent, Eshel shows a three lumen catheter with a centrally located urinary drainage lumen.
Still other devices have been described for importing fluid into the body and allowing a means for removing fluid from the body. One such device is described in U.S. Pat. No. 3,087,493, issued Apr. 27, 1960 to Schossow, entitled “Endotracheal Tube”. Schossow describes a device employed to intubate the human trachea. The device is connected with ducts and/or tubes outside the patient for the purpose of, for example, drawing off from the patient's respiratory tract undesirable liquids and/or introducing beneficial liquids into the trachea. The device comprises an outer tube, which fits inside the patient's trachea, and a two layered inner tube. The lumen of the inner tube is open to be connected with devices or ducts through which suction may be applied or fluids injected into the trachea. The distal portion of the inner tube is vented with ports or openings that create a “sprinkler” effect inside the tube.
During cryoablation, the prostate tissue is killed by freezing temperatures in the cryogenic temperature range, typically −120° C. and below. The hot fluid used for the warming catheter is supplied at about 30° C. to 50° C. Warm fluid is pumped through the urethral warming catheter, such as the catheter described in Baust et al. Using this catheter, as the warm fluid travels the length of the urethral catheter disposed within the cryosurgically-cooled urethra, it is cooled by the surrounding freezing tissue. By the time the hot water has traveled from the bladder neck sphincter to the external sphincter, it has been significantly cooled by the surrounding frozen prostate. As a result, the urethral tissue near the bladder neck sphincter (near the hot water outlet) is heated more than the urethral tissue near the external sphincter, creating a strong thermal gradient in the prostatic urethra and an uneven heating effect. By the time the hot water reaches the external sphincter, it may have lost so much heat to the upper region of the urethra that it is not warm enough to protect the external sphincter from freezing. In order for the tissue at the bladder neck sphincter to be adequately warmed, hotter water must be pumped in, risking urethral damage due to scalded tissue, or more water must be pumped at higher rates and pressures, increasing the material requirements of the hot water supply system and the warming catheter.
U.S. Pat. No. 6,017,361, issued to Mikus et al, entitled Urethral Warming Catheter, discloses an improved method and means for maintaining the temperature of urethral tissues during cryoablation of the prostate gland and thereby eliminates or reduces the sloughing of dead cells into the urethra. Diffuser holes or ports, much like a “sprinkler,” are drilled into the inner tube of the warming catheter. The holes create an advantage over the prior art of achieving improved uniformity of fluid flow and temperature, utilizing a lower initial temperature and resulting in a more even application of thermal treatment to the urethral tissues. The apparatus may find additional utility in other areas of surgery where thermal treatment or maintenance of tissues is required with or without the capability of drainage.
U.S. Pat. No. 6,067,475, issued to Kenneth L. Graves et al, entitled Microwave Energy Delivery System Including High Performance Dual Directional Coupler for Precisely Measuring Forward and Reverse Microwave Power During Thermal Therapy, discloses a microwave energy delivery system for microwave thermal therapy that includes an antenna and a transmission line connected to the antenna. A microwave generating source includes a generator connected to the transmission line and a dual directional coupler for detecting forward power delivered to the antenna and reverse power reflected from the antenna with low uncertainty.
In one broad aspect the present invention is a method for warming the urethra of a patient during ablative surgery. In this method, at least one ablative surgical device is inserted into a prostate region of the patient. A warming assembly is inserted through the patient's urethra and at least to the bladder neck. The warming assembly is operated to warm an outer surface thereof during operation of the ablative surgical devices. The urethra is warmed by the outer surface of the warming assembly to preserve living tissue thereof.
The present invention is particularly advantageous for use during cryosurgical ablation of the prostate utilizing cryosurgical probes. In one implementation, the warming assembly comprises a warming subassembly with a central opening. The central opening can accommodate, for example, a drainage tube or an endoscope.
The warming catheter may comprise an electrically generated warming assembly that is inserted through the patient's urethra and at least to the bladder neck. In one implementation an electrical coil heated warming catheter subassembly is utilized. In another implementation the electrically generated warming assembly comprises a microwave heated warming catheter subassembly. In another implementation the electrically generated warming assembly comprises an RF heated warming catheter subassembly.
a is an enlarged perspective view, partially in section, of a portion of the warming assembly of
b is a view taken along line 8b-8b of
Referring now to the drawings and the characters of reference marked thereon,
The ablative devices are preferably cryosurgical probes such as manufactured and marketed by Endocare, Inc., of Irvine, Calif. The figure shows use of six cryosurgical probes 14 as well as four temperature probes 18. Alternatively, other ablative devices may be used, for example, radio frequency electrodes, laser fibers, microwave catheters, or high-intensity focused ultrasound. In such instances the heat exchange fluid is cool so as to prevent the urethra from the heating by the ablative elements.
In this first embodiment illustrated, the warming assembly 20 is a Joule-Thomson warming assembly, including an insertable Joule-Thomson warming subassembly 22, a connector element 24, an inlet subassembly 26, and an outlet subassembly 28. The outlet subassembly 28 is preferably formed of a flexible material such as one of various suitable plastics, for example, polyethelene. The connector element 24 is a suitable rigid material such as polycarbonate. The inlet subassembly 26 is connected to a high pressure gas source (not shown), preferably helium. Other suitable gases may be utilized that heat while undergoing Joule-Thomson expansion.
Although not shown, the inlet subassembly 26 receives heat exchange fluid from a pump and warmer, which are, in turn, connected to a reservoir. Generally, the warming gas should be supplied at pressures that cannot result in Joule-Thomson warming to temperatures sufficient to thermally damage the urethra.
Referring now to
Referring now to
As in the previous embodiment the electrical coil heated warming catheter subassembly 42 preferably includes an elongated opening 48 to provide, for example, access for an endoscope and/or drainage for bladder fluid.
Referring now to
U.S. Pat. No. 4,967,765 entitled “Urethral Inserted Applicator For Prostate Hyperthermia”, discloses another system for treating BPH. U.S. Pat. No. 5,249,585, entitled “Urethral Inserted Applicator for Prostate Hyperthermia,” discloses another such system. U.S. Pat. No. 5,509,929, entitled “Urethral Probe and Apparatus For the Therapeutic Treatment of the Prostate By Themotherapy,” discloses use of a microwave antenna directed onto the prostatic tissues located at least at the level of the bladder neck in the working position. U.S. Pat. No. 5,480,417, entitled “Method and Apparatus For the Surgical Treatment of Tissues by Thermal Effect, and in Particular the Prostate, Using a Urethral Microwave-Emitting Probe Means,” discloses another system for providing thermotherapy of the prostate.
As in the previous embodiments the microwave heated tube warming catheter subassembly 52 preferably includes an elongated opening 58 to provide, for example, access for an endoscope and/or drainage for bladder fluid.
Referring now to
As in the previous embodiments, the RF heated warming catheter subassembly 62 preferably includes an elongated opening 66 to provide, for example, access for an endoscope and/or drainage for bladder fluid.
Referring again to
Thus, while the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the invention. Other embodiments and configurations may be devised without departing from the spirit of the invention and the scope of the appended claims.
This application is a divisional of U.S. Ser. No. 10/426,807 filed on Apr. 30, 2003.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10426807 | Apr 2003 | US |
| Child | 10894789 | Jul 2004 | US |
