A DEVICE FOR MAINTAINING A PASSAGE FOR URINE THROUGH THE PROSTATE

Abstract: A device for maintaining a passage through the prostate gland (13) after treatment of a catheter (10) inserted through the urethra into the prostate gland, said catheter (10) being provided with means (11) for heating prostate gland. A sleeve (12) is received over the catheter (10) so as to follow the catheter (10) during insertion into a desired position within the prostate gland, and said sleeve (12) is formed to remain in said position when the catheter is removed from the prostate gland, thereby maintaining a passage having a predetermined lower inner diameter through the prostate gland when tissue in the prostate gland swells.

Description: A Device for Maintaining a Passage for Urine through the Prostate . _ . . . . Technical field Prostate trouble, such as benign prostate hyperplasia (BPH) or chronic prostatism are found normally among men. In many cases the symptoms are experienced as very troublesome, and therefore numerous different forms of treatments have been developed. Several of these result in transitory trouble for some time after treatment. The invention relates to a device for maintaining a passage for urine through the prostate gland as claimed in Claim 1. Prior art The purpose of microwave treatment and other heat treatments of the prostate gland is to accomplish an amount of dead tissue in the gland. The dead tissue is discharged in different ways, mainly through the urethra to¬ gether with urine. In connection with the treatment it is not unusual that an acute reten¬ tion of the urinary tracts occurs to the patient. This is a result of a swelling of the heat treated prostate gland which closes the drain of urine. The effect can remain for a few months and is very troublesome to the patient. To ensure a drainage of urine also during this period of time it is pres¬ ently a normal step to insert a urine catheter during the time there is a swel¬ ling of the gland. Though there is a drain of urine according to this method the catheter as such is a problem to the patient. Description of the invention An object of the present invention is to limit the risk of the troubles described above after treatment of the prostate gland. This object has been achieved according to characteristics of claim 1. According to the invention a stent or sleeve or similar element is in¬ serted in the prostate gland during the treatment. The sleeve is left after a completed treatment and remains in position during the time the tissue is swollen. Preferably the sleeve is performed as a helical winding made of a material which after some time delay is solved in contact with body tissue. An example of such a material is polyglycol acid (PGA). It is also possible to use a flexible tube. Detailed description According to the invention there is used a so called expanding stent or similar device, such as a flexible tube, which after completed treatment is attached along the prostatic urethra within the prostate gland in such a way that it prevents the swollen tissue from closing the drain of urine, instead maintaining an opening for a drain of urine. The Figure shows an embodiment according to the invention using a stent 12 formed as a helical thread made of a suitable material. The stent 12 is arranged externally on a catheter 10 which during treatment is inserted through the urethra until a tip 15 has entered into the bladder 14. A balloon 16 following the catheter 10 into the bladder 14 is expanded through a duct in the catheter 10 to hold the catheter 10 in position in relation to the prostate gland 13. Within the catheter 10 there are provided means 11 for heating prostate tissue to such an extent that some tissue will be dead. Said means 11 preferably comprise a microwave antenna. To avoid too much dead tis¬ sue in the vicinity of the antenna cooling ducts can be provided in the cathe¬ ter 10. Another way of providing a desired heating is to circulate heated liq¬ uid in a section of the catheter 10 positioned within the prostate gland, or in a separate container of the catheter. It is also possible to provide separate heating means locally at the area of treatment and thereby to accomplish a local heating without any demand of cooling of surrounding tissue. The heating means may e.g. be some type of antenna which emits radio signals of a frequency in the interval 0,1-1000 MHz, or a volume of a liquid which is heated by a heating element. The sleeve or the stent 12 is provided on the outside of the catheter 10. The stent 12 comprises a thread of a material that will be solved in the tissue. The thread is winded in a helical winding. Preferably the inner diame¬ ter of the stent 12 is somewhat larger than the outer diameter of the catheter 10 to allow the stent 12 to slide comparatively freely on the outside of the catheter, and the outer diameter of the stent 12 is somewhat larger than the inner dimensions of the urethra through the prostate gland to fix the stent 12 to an appropriate extent within the prostate gland. The stent 12 can also be formed as a grid or a fabric. During the treatment the stent 12 is passive and does not affect in any way the result of the treatment. After a completed treatment the balloon 16 is emptied. Then the catheter 10 is pulled out. To ensure that the stent 12 fol¬ lows the catheter 10 into the desired location within the prostate gland wedgeshaped abutments 17 are provided on the outside of the catheter 10. In the shown simple embodiment it is the chosen dimensions of the stent and catheter that prevent the stent from following the catheter out from the pros- tate gland. It is also possible to accomplish the same function with a flexible tube having a balloon-formed outer section which can be inflated and accomplish a mechanic contact with the prostate gland to accomplish the desired holding in position. It is also possible to hold the tube in other ways. However, the tube should be removable so as to be removed when it is less required. Normally, the requirement is smaller within 1-3 months. If a tube is used in¬ stead of a stent it is appropriate to provide a tube with ducts for draining the prostate gland. In this way it will be possible for treated and rejected ne- crotized tissue to be passed off through the urine. In both embodiments the axial extension of the tube of the stent should not exceed the length of the prostate gland because the external sphincter adjacent to the rear part of the prostate gland should not be func¬ tionally disordered. In some cases it is appropriate to hold the stent 12 or the tube by means of a separate tool in an immediate connection to the completion of the treatment. If a non-absorbing tube is used the tube is removed manually as soon as the tissue no longer is swollen. In such an embodiment the tube can be provided with a thread which is available and which can be used to pull out the tube. It is also possible to catch the tube and then pull it out. To improve the transfer of heat between the heating means 11 and the tissue that is treated it may be appropriate to connect said means 11 to some type of heat conveying expansion means. The expansion means may include bimetal or any similar means which by an expansion will reach a good contact to the tissue.

Claims: CLAIMS 1. A device for maintaining a passage through the prostate gland (13) after treatment by a catheter (10) inserted through the urethra to the prostate gland, said catheter (10) being provided with means (11) for heating prostate tissue, characterized in that a sleeve (12) is received over the catheter (10) to follow the catheter (10) during insertion into a desired position within the pros¬ tate gland, and that said sleeve (12) is formed to remain in that position when the catheter is removed from the prostate gland, thereby maintaining a passage having a predetermined lower inner diameter through the prostate gland when tissue within the prostate gland will swollen. 2. A device according to Claim 1 , characterized in that the sleeve (12) is made of a material which will be absorbed in the body tissue. 3. A device according to Claim 1 , characterized in that the sleeve (12) is provided with means that is controlled from outside the body to hold the position of the sleeve (12) in the prostate gland. 4. A device according to any of Claims 1-3, characterized in that the heating means (11) comprises an antenna for emitting electromagnetic ra¬ diation. 5. A device according to any of Claims 1-3, characterized in that the heating means (11) comprises a liquid container connected to a heating element for heating liquid enclosed in said container. 6. A device according to any Claims 1-3, characterized in that the heating means (11) is connected to expansion means, said means expand- ing when heated in the direction of surrounding prostate gland tissue so as to increase the transfer of heat to said tissue.

Inventors: BOLMSJOE MAGNUS, BOLMSJOE, MAGNUS
Applicants: BOLMSJOE MAGNUS, LUND INSTR AB, BOLMSJOE, MAGNUS, LUND INSTRUMENTS AB
Application year: 1996
Main classification: A61F2
IPC codes: A61B17, A61B18, A61F2, A61F7