WO2005115245A1

WO2005115245A1 - Intravesicular device

Info

Publication number: WO2005115245A1
Application number: PCT/IL2005/000550
Authority: WO
Inventors: Margot Damaser; Daniel Yachia; Alfred Perlin; Paul Zaszczurynski; James Walter
Original assignee: Dynaventions Inc.
Priority date: 2004-05-28
Filing date: 2005-05-29
Publication date: 2005-12-08

Abstract

The invention provides a system and method for determining urine volume in a urinary bladder. The system comprises an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder. The method comprises determining a urine volume in a urinary bladder comprising deploying in the urinary bladder an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder. Urine volume in the bladder is obtained from the conductance determinations.

Description

INTRAVESICULAR DEVICE

FIELD OF THE INVENTION The invention is in the field of implantable medical devices.

BACKGROUND OF THE INVENTION Urinary Incontinence (UI), the involuntary leakage of urine from the bladder, is a common and debilitating problem for more than 40 million people worldwide. Its prevalence is higher among women and increases with increasing age. The inability to control the flow of urine may stem from detrusor overactivity, resulting in urge incontinence, or from sphincteric weakness and/or urethral hypermobility resulting in stress incontinence. More than 15 million people in the United States suffer from urinary incontinence. UI is a significant medical condition of the elderly, affecting women to a greater extent than men: 25-60% of postmenopausal women have UI¹. Conservative estimates of healthcare costs in the United States for diagnosis and treatment of UI exceed $10 billion annually. The societal cost of urinary incontinence has been estimated at $16-26 billion. While UI is not a life threatening condition, it reduces the quality of life of those who suffer from it. Forty percent of incontinence patients have anxiety and 14% have depression. Fifty percent of elderly people with severe depression have incontinence. In addition, UI is one of the primary reasons that elderly people are placed in nursing homes: up to 50% of nursing home residents are incontinent. Therefore, UI is a common condition with high societal cost, primarily because of its high prevalence and effect on quality of life. The current gold standard method of diagnosing UI and bladder dysfunction is a urodynamics examination in which a catheter is passed through the urethra into the bladder that is used to retrogradely fill the bladder and measure bladder pressure (vesical pressure, or P_ves). A rectal probe is used to record abdominal pressure, P_abd, and the detrusor pressure (Pd_et), is calculated as:

The volume of urine in the bladder at the first sensation, maximum capacity, frequency of spontaneous unwanted bladder contractions, pressure at urine leakage, and pressure and flow rate during voiding are among the measured parameters. Diagnosis of stress incontinence is often made by measuring leak point pressure (LPP): the patient coughs or bears down until leakage occurs while vesicle pressure is measured. Urodynamics is an extensive clinical evaluation involving significant cost and time by both the patient and the health care system and is therefore utilized mostly at tertiary care centers, usually university medical centers. In addition to being expensive and uncomfortable, urodynamics is a nonphysiological examination: it is performed in an artificial laboratory environment, the patient has little or no privacy, the bladder is catheterized through the urethra, and the bladder is filled retrograde with a room temperature isotonic saline solution or gas at rates often 10 times greater than physiological filling rates. The urinary bladder is a temperature-sensitive viscoelastic-plastic organ which responds to increased filling rate and low temperature with increased pressure and increased slope of the bladder pressure-volume relation. Therefore, because of the low temperature of the saline or gas, and the high filling rates, the bladder may exhibit responses that are not representative of normal bladder activity. A urodynamics test often results in difficulty reproducing patient complaints and symptoms of both urge and stress incontinence. All recordings are made through catheters, tethering the patient for the duration of the test, interfering with some flow rate measurements, and adding to patient discomfort. Despite attempts during urodynamics testing to simulate certain activities (coughing, sitting, walking, etc.), it is a one time spot examination that is not carried out under circumstances that are representative of the patient's routine activities. Efforts have been made to record bladder pressures in a more physiological manner via ambulatory monitoring. Urethral and rectal catheters are inserted into the patient and kept in place for several hours during which time, bladder pressures are recorded on a holter monitor. During ambulatory monitoring, the bladder fills physiologically (anterograde from kidneys through ureters to the bladder), and at a physiological rate However, the indwelling catheter is often uncomfortable and causes bladder contractions by irritating the urethra and bladder wall. Bladder volume cannot be measured during ambulatory monitoring and has to be inferred posthoc from resultant voiding data. Conductance measurements of blood have been used to measure blood volume in the heart chambers. This method takes advantage of the fact that the resistivity (the inverse of conductivity) of blood (r=160 Wcm) is significantly lower than that of the myocardium (r_w=400 Wcm) and the tissues surrounding the heart. Conductivity is an intrinsic property and does not vary with increasing volume. In contrast, conductance is a volumetric measure and varies with volume. The volume of the left ventricle (LV), for example, has been measured using a conductance catheter placed inside the LV. The method most often used to determine LV conductance is a dilution technique, which relies on the analysis of the conductance signal during an induced transient change in blood conductivity. A small bolus of hypertonic saline is injected into the pulmonary artery. As the saline/blood mixture enters the LV, a temporary, gradual change in the conductance signal occurs over several heart beats. The increase in the conductance (or volume) signal is then analyzed to extrapolate the effects of decreasing conductivity. The conductance catheter is an insulated catheter having two or more electrode pairs spaced along the portion of the catheter inserted into the LV. A weak alternating current is generated between the most distal and the most proximal electrodes. The electrodes in between measure the potential differences from which conductance is derived, since volume cannot be directly calibrated. The conductance technique has been applied to measure the cross- sectional area of the urethra in both women and men (Bagi, P. Urol. Res. 30:1-8, 2002). Two excitation and two signal electrodes were used to measure urethral cross-sectional area during a step-wise forced dilation procedure. PCT Publication WO 04/041242 discloses a balloon for insertion into the urinary bladder.

SUMMARY OF THE INVENTION The present invention provides a system and method for testing and monitoring urinary bladder function. The system of the invention monitors urine volume in the bladder continuously or periodically. The invention allows urodynamic measurements both in the laboratory and at home during activities of normal daily living, unencumbered by externally communicating catheters or wires. In accordance with the invention, a conductance probe is mounted on an intravesicular device that is delivered deployed in the bladder. In one embodiment, the device is a balloon that is filled with biocompatible fluid, which may be a liquid or a gas, having a specific gravity less than that of urine, so that it floats on the urine in the bladder. Alternatively, the device may be compressed prior to deployment in the bladder and then released in bladder and allowed to regain its original shape. In a preferred embodiment, the device, when deployed, has a torroidal shape and electronic components associated with the device are contained in an insert immobilized in the central hole of the torus. Conductance measurements obtained by the probe may be stored on a data acquisition chip associated with the device. In this case, the data may be read after retrieval of the device from the bladder. In a preferred embodiment, the conductance measurements are wirelessly transmitted to a receiver located in a control unit. The control unit may be contained in a pouch adapted to be attached to the user's belt. Determination of urine volume determination based upon conductance measurements is dependent on urine temperature and possibly on other physiological variables (i.e. urine pH). Therefore, those parameters are preferably measured by the system in order to improve the accuracy of the volume measurement. When desired, device is retrieved from the bladder. The system of the invention may further comprise an intravaginal or intrarectal probe that measures abdominal pressure and temperature as well as patient position and acceleration. The system of the invention may also comprise a wireless microphone or event marker to allow the user to record relevant remarks. The system amy also include a heart rate sensor for recording the user's heart rate. The system includes a processor that is configured to calculate a urine volume in the bladder from the conductance measurements recorded by the conductance probes. The resistivity of the bladder wall is 500 Wcm and that of urine is 33 Wcm, making the bladder to urine resistivity ratio equal to 15. A calibration curve can be made in each patient at the time of balloon insertion by measuring volume during bladder filling and/or voiding. The control unit may also store correction factor tables or correction functions that are utilized in the calculation of the urine volume.

The processor may perform several additional functions, such as : 1. Recording patient notations regarding urgency and/or incontinence episodes and physical activity, such as jumping, running, lifting, sneezing, or coughing, with the help of a voice recorder or event marker. 2. Continuously managing and storing the data from the probes and sensors of the system. 3. Interfacing with external computers and monitors; 4. Sending energy to transponders, for charging batteries associated with the implanted device; The system of the invention has the following features: 1. No catheters or wires extend out of the urethra, vagina, or anus; 2. Decreased provider time for testing, since after the insertion of the devices, the user may be released from the clinic so that the user may carry on his or her normal activities of daily living while data are recorded. 3. The urodynamics exam can be extended to a home environment with natural filling rates and temperatures; 4. Many bladder filling and emptying cycles can be monitored over a 1 to

2 day testing period; 5. Measurements of patient position, movements, remarks pertaining to feeling or urgency, leakage, and emotions at the time of leakage can be collected along with bladder pressure, volume, and flow rate (a derived variable), as well as pH and temperature. The conducatance probe is preferably part of an ultraminiature device asocaiated with the device that includes a large diversity of electronics, including sensors, sensor interfaces, signal conditioning, a microprocessor core, memory, digital signal processing and wireless transmission technology. The sytem of the invention may be used by individual physicans, nursing homes and clinics which cannot afford expensive urodynamic equipment. The system may also be used as a long term indwelling device to notify patients, such as those with diabetes or spinal cord injury, who have lost bladder sensation, about the need to void based on volume and/or pressure thresholds. The system may be adapted to administer pharmacologic agents or electrical stimulation, sounding an alarm and ceasing treatment if threshold bladder volumes or pressures are exceeded. Thus, in its first aspect, the invention provides a system for determining urine volume in a urinary bladder comprising an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder. In its second aspect, the invention provides a method for determining urine volume in a urinary bladder comprising deploying in the urinary bladder an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder.

BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non- limiting example only, with reference to the accompanying drawings, in which: Fig. 1 shows a system for measuring urine volume in a bladder in accordance with one embodiment of the system of the invention; Fig. 2 shows a balloon for use in the system of Fig. 1 having a duck-bill type valve for filling from a syringe; Fig. 3 shows a balloon for use in the system of Fig. 1 having a ball valve for filling from a syringe; Fig. 4 shows deployment of the balloon system of the system of Fig. 1 in a female subject; Fig. 5 shows retrieval of the balloon; Fig. 6 shows a system for volume measurements in an excissed pig bladder; and Fig. 7 shows the output of the sensing electrodes of the system of Fig. 6 during three trials of filling and emptying the bladder.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS Reference is now made to Fig. 1 which shows a system 90 for measuring and monitoring the volume of urine in a urinary bladder in accordance with one embodiment of the invention. The system 90 includes a balloon system 100 comprising a balloon 1 having a wall 2 made of a flexible biocompatible material enclosing a lumen 4. In this embodiment, the balloon, after inflation, has a torroidal shape defining a central hole 80 that is generally cylindrical in shape. The balloon 1 may have an overall spherical shape, as shown in Fig. 1. This is by way of example only, and other shapes for intravesicular device, such as a cylindrical or ellipsoidal shape, are also contemplated within the scope of the invention. The balloon system 100 also includes a generally cylindrically shaped insert 82. The insert 82 is dimensioned to be received in the hole 80, as shown in Fig. lb. Grooves and ridges 84 on the external surface of the insert 82 may be received in complementary grooves and ridges 86 on the external surface of the wall 2 so as to retain the insert in the hole 80, and to prevent separation of the insert 82 from the balloon 1 during use of the system 100. The insert 100 may also be held in place in the hole 80 by means of an adhesive or by welding. In accordance with the invention, the balloon system 100 comprises a conductance probe. In the embodiment of Fig. 1, the conductance probe consists of at least one pair of conductance electrodes 101a and 101b, for measuring urine conductance after deployment of the balloon 1 in the urinary bladder and at least one pair of excitation electrodes 103a and 103b, after deployment of the balloon 1 in the urinary bladder, as described in detail below. After insertion of the insert 82 into the hole 80, the electrodes are connected to the insert via contacts 102 that may be wires or printed or deposited metal channels. The electrodes may be, for example, a thin foil of platinum, or elgiloy

(also know as Phynox). The electrodes may be adhered to the balloon surface with an adhesive that is flexible and biocompatible, such as silicones (e.g. Dow 748) or polyurethane (e.g. McMaster-Carr #7606A22) based adhesives. The electrodes may also be prepared by metal deposition (e.g. sputtering) directly onto the balloon surface. The electrodes may also be prepared from flexible conductive adhesives (silver-filled conductive adhesives) and hot melts. The surface of the electrodes may be provided with bumps (not shown) on their surface in order to increase the area of contact between the electrodes and the urine. The insert 82 may also include temperature and pH transducers. The insert 82 also includes a transmitter 83 for transmitting conductance measurements and other data collected by the balloon system 100 to a control unit 84. The control unit 91 has a receiver 86 that receives the transmitted data and stores the data in the memory 93. The control unit 91 also includes a processor 92 that processes the received data and stores the data in the memory 93. The processing may include determining a urine volume in the bladder. Determining a urine volume from the conductance measurements may be done using a calibration curve or look-up-table obtained on the user at the time the balloon system 100 is deployed. A calibration curve or look-up table may be obtained by filling the bladder with a known volume of saline and determining the output of the signal probes. Volume determination based on conductance measurements is sensitive to urine temperature and conductivity and possibly on other physiological variables (i.e. urine pH). Therefore, those parameters are preferably measured by the balloon system 100 and transmitted to the processor 87 in order to improve the accuracy of the volume determination. The processor 92 may also be configured to communicate with an external computer (not shown) for examination or further analysis of the data. The control unit 91 may be enclosed in a pouch 81 adapted to be carried by the user. For example, the pouch 81 may be provided with one or more loops 94 to allow the pouch 81 to be mounted onto the user's belt and to be carried on the user's waist. The system of the invention may further comprise a probe 17 that measures abdominal pressure, temperature, acceleration, and position data (inclinometer). The probe may be adapted for insertion into the rectum, or, in the case of a female user, into the vagina. The accelerometer is used for detecting dynamic events that can influence bladder dynamics (cough, sneezing, falling, running, etc.) The inclinometer provides additional information about body orientation (lying, sitting, standing, etc.). Bladder and abdominal pressure, from the intravesicular device and the probe 17, respectively, may be used by the processor 87 to calculate detrusor pressure according to equation (a) above. Bladder volume is necessary to determine the volume at leakage, voiding, and/or high bladder pressures. Flow rate during voiding and volume of leakage can be derived from intravesical volume. The pressure sensor may be, for example, an ultraminiature pressure sensor made by Entran Co. (model EPE-54X). For temperature monitoring, Omega's thin Film RTD elements may be used. For readout, an Omega monitor model DP460- RTD may be used. For conductivity measurements, the fast conductivity sensor made by Precision Engineering Co. may be used and for readout a micro scale conductivity and temperature instrument may be used. For acceleration and position determination, the Analog Device accelerometer ADXL320 and inclinometer (SignalQuest SQ-S12X-360DA), respectively, may be used. The system of the invention may also comprise a wireless microphone and associated transmitter 97, or an event marker (not shown) that transmits the user's remarks to the control unit 84. The system 100 further includes an applicator 20 for deploying the balloon 1 in a urinary bladder, and a retriever 30 for retrieving the balloon 1 from the bladder, described in detail below,. The balloon 1 or the insert 82 may further comprise a magnetizable portion 3 in order to assist in deploying the balloon 1 in the urinary bladder or in retrieving the balloon 1 from the bladder. The magnetizable portion 3 may consist for example, of one or more metal particles which may be free in the lumen 3a of the balloon 1 (as in Fig. lb), attached to the inner surface 3b of the balloon 100 (as in Fig. lc), embedded in the wall 3c of the balloon 1 (as in Fig. Id), or attached to the insert 82 (3e) as shown in Fig. le. A self-sealing valve 5 in the wall of the balloon is used to fill the balloon. The valve 5 may be for example a duck-bill type valve as shown in Fig. 2 or a ball valve as shown in Fig. 3 in which a ball 8 may be in a sealing position (Fig. 3 a) or an unsealing position (Fig. 3c). The cannula 6 of a syringe 7 is inserted through the valve 5 into the lumen 4 of the balloon. Fluid 24 is injected into the lumen 4 from the syringe 7 causing the balloon to expand. After filling, the syringe needle 6 is withdrawn, and the valve 5 seals itself. The fluid is a biocompatible fluid having a specific gravity less than that of urine, that may be pre-sterilized, such as air or an oil such as liquid paraffin. The inflated balloon thus floats in the urine. Fig. 4 shows use of the applicator 20 for deploying the balloon system 100 into the lumen 41 of the urinary bladder 42 of a female individual. The balloon system 100 is initially grasped by the closed flanges 23a at the distal end of the applicator 20 (Fig. 4a). The distal end of the applicator-device combination is inserted into the urethra until it reaches the lumen 41 of the bladder 42. The balloon 1 is then filled and the balloon system 100 is then released from the applicator by opening the flanges 23b by pulling on ring 25 while holding the constraining sleeve 26. The applicator 20 is then removed from the body, leaving the balloon 1 in the bladder lumen 41. Fig. 5 shows use of the retrieval device 30 for removing the device 100 from the bladder. A catheter 27 has at its distal end 28 a magnetizable portion 29 so as to hold the balloon at the distal end 28 by means of the magnetizable particles 3 associated with the balloon system 100. The retrieval device is inserted into the bladder. After opening the flanges 31 of the retrieval device, the engaging probe 32, with magnetizable portion 29 in its tip, is inserted into the bladder so as to engage the magnetizable particle 3. The probe 32 is then pulled so as to bring the device into the grasp of the flanges 31 of the retrieval device. A piercer 33 is inserted into the balloon 1 to drain the fluid contained in its lumen 4 into an attached syringe (not shown) or into the body cavity. The retrieving device 30 is then withdrawn from the patient together with the deflated balloon 1 and the insert 82. As disclosed in PCT Publication WO 04/041242, the insert the insert 82 may optionally be configured to release one or more substances in the urinary bladder such as pharmaceuticals, immunoglobulins, or radioactive substances. The insert 82 may optionally comprise a micro-video camera for. imaging the interior of the bladder. The insert 82 may optionally comprise one or more measuring devices for measuring one or more parameters associated with the bladder, for example, urine pressure, urine temperature, urine density, or fluid composition. Measurements recorded by the measuring devices may be transmitted to the control unit 84. As further disclosed in PCT Publication WO 04/041242, the system may further comprise a displacing member comprising a magnetizable portion to position the balloon system 100 at a desired location within the urinary bladder. The displacing member is placed at a location on the surface of the user's body so as to draw the balloon to a desired location in the bladder by the magnetizable particle 3 associated with the balloon system. The system may then be used for treating urinary incontinence. Examples A spherical probe was designed having electrodes on its surface. As shown in Fig. 6, a spherical probe 105 was fitted with four electrodes each of which consisted of a 1/8 by 2 inch metal strip. Each electrode covered an arc of about 30° along a circumference of the sphere. A pair of excitation electrodes 110a and 110b were placed on a first circumference and a pair of signal electrodes Ilia and 111b were placed on a second circumference that was perpendicular to the first circumference. The probe 105 was immersed in an excised pig bladder 115. The bladder 115 was immersed in a temperature controlled water bath 130 that was provided with an accelerometer 135. The bladder 115 and the probe 105 were held in place holder 113. A conductivity sensor 140 and a pressure sensor 145 were also positioned in the saline 120. The excitation electrodes 110a and 110b were connected to a signal generator 150 via wires 151a and 151b, respectively. A 1000 Ohm resistor 160 was included in the circuit. The signal electrodes Ilia and 111b were connected to an amplifier recording system 162 via wires 163a and 163b, respectively. A selectable amount of saline 120 was introduced from a source (not shown) into the bladder via a pump 168 and delivery tube 169. An experiment was conducted to determine the voltage output of the signal electrodes as a function of the volume of saline in the bladder. Fig. 7 shows the results obtained from three trials consisting of filling and emptying of the bladder. A square wave signal (800 Hz, IV amplitude) was input to the excitation electrodes and the output voltage from the signal electrodes was recorded as the bladder was first filled and then emptied of saline.. The output voltage range from 10 mV to 19.5 mV gave the lowest volume measurement error and the greatest reproducibility at the sensing electrodes. A curve of the type shown in Fig. 7, when obtained by the system 100 in the urinary bladder of a user at the time of deployment of the system 100 in the bladder, can be used as a calibration curve for subsequent volume determinations based upon conductance measurements.

Claims

CLAIMS:

1. A system for determining urine volume in a urinary bladder comprising an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder. 2. The system according to Claim 1 wherein the intravesicular device comprises a memory for recording conductance measurements obtained by the conductance probe.

3. The system according to Claim 1 or 2 wherein the intravascular device further comprises one or more probes selected from the group: (a) a temperature probe measuring urine temperature; (b) a pH probe measuring urine pH; and (c) a conductivity probe measuring urine conductivity.

4. The system according to any one of the previous claims wherein the intravesicular device further comprises a transmitter for transmitting determinations obtained by any one or more of the probes to a control unit.

5. The system according to Claim 4 wherein the determinations are transmitted in a wireless fashion.

6. The system according to any one of the previous claims further comprising an abdominal probe configured to measure any one or more of abdominal pressure, temperature, acceleration, and position.

7. The system according to Claim 6 wherein the abdominal probe is adapted for insertion into a rectum or vagina.

8. The system according to Claim 6 or 7 wherein the abdominal probe comprises a transmitter for transmitting measurements from the abdominal probe to a control unit.

9. The system according to any one of the previous claims further comprising a control unit for receiving data transmitted from the intravesicular device and/or the abdominal probe.

10. The system according to Claim 9 wherein the control unit comprises a processor configured to determine a urine volume in the urinary bladder based upon conductance measurements obtained by the conductance probe. 11. The system according to Claim 10 wherein the processor is configured to 5 determine the urine volume based upon any one or more of a urine temperature, a urine pH and a urine conductivity. 12. The system according to Claim 10 or 11 wherein the processor is configured to determine the urine volume using a look-up table or calibration curve stored in a memory associated with the processor.

10 13. The system according to any one of Claims 10 to 12, wherein the processor is further configured to communicate data to a remote computer. 14. The system according to any one of Claims 9 to 13 wherein the control unit is adapted to be attached to a user's clothing. 15. The system according to any one of the previous claims wherein the 15 intravesicular device is an inflatable balloon. 16. The system according to Claim 15 wherein the balloon comprises a self-sealing valve. 17. The system according to any one of Claims 1 to 14 wherein the intravesicular device is compressible.

20 18. The system according to any one of the previous claims wherein the intravesicular device is torroidal in shape defining a hole adapted to receive an insert containing one or more electronic elements. 19. The system according to any one of the previous claims further comprising an applicator for deploying the intravesicular device in the urinary bladder. 25 20. The system according to any one of the previous claims further comprising a retriever for retrieving the intravesicular device from the urinary bladder. 21. The system according to any one of the previous claims wherein the intravesicular device comprises a magnetizable portion.

22. The system according to any one of the previous claims wherein the intravesicular device floats in urine when deployed in the urinary bladder. 23. The system according to any one of the previous claims, wherein the intravesicular device is capable of storing one or more compounds and releasing 5 them into the urinary bladder. 24. The system according to any one of the previous claims, wherein the intravesicular device comprises a method for imaging the urinary bladder. 25. The system according to Claim 21, further comprising an immobilizing member comprising a magnetizable portion for immobilizing the intravesicular device at a

10 desired location in the body cavity. 26. An intravascular device for use in the system of any one of the previous claims. 27. A method for determining urine volume in a urinary bladder comprising deploying in the urinary bladder an intravesicular device having a conductance probe adapted for determining a urine conductance in the bladder.

15 28. The method according to Claim 27 comprising making one or more determinations from the group selected from: (a) urine temperature; (b) urine pH; and (c) urine conductivity.

20 29. The method according to Claim 27 or 28 further comprising transmitting determinations obtained by any one or more of the probes to a control unit. 30. The method according to Claim 29 wherein the determinations are transmitted in a wireless fashion. 31. The method according to any one of Claims 27 to 30 further comprising 25 inserting into an abdomen an abdominal probe configured to measure any one or more of abdominal pressure, temperature, acceleration, and position. 32. The method according to Claim 31 wherein the abdominal probe is inserted into a rectum or vagina.

33. The method according to Claim 31 or 32 further comprising transmitting measurements from the abdominal probe to a control unit. 34. The method according to any one of Claims 27 to 33 further comprising determining a urine volume in the urinary bladder based upon conductance 5 measurements obtained by the conductance probe. 35. The method according to Claim 34 comprising determining the urine volume based upon any one or more of a urine temperature, a urine pH and a urine conductivity. 36. The method according to Claim 34 or 35 comprising determining the urine 10 volume using a look-up table or calibration curve. 37. The method according to any one of Claims 27 to 36 comprising communicating data to a remote computer. 38. The method according to any one of Claims 27 to 37 wherein the intravesicular device is an inflatable balloon.

15 39. The method according to any one of Claims 27 to 37 wherein the intravesicular device is compressible. 40. The method according to any one of Claims 27 to 39 wherein the intravesicular device is torroidal in shape defining a hole adapted to receive an insert containing one or more electronic elements. 20 41. The method according to any one of Claims 27 to 40 further comprising a retrieving the intravesicular device from the urinary bladder. 42. The method according to any one of Claims 27 to 41 wherein the intravesicular device floats in urine when deployed in the urinary bladder. 43. The method according to any one of Claims 27 to 42 further comprising storing 25 one or more compounds in the intravesicular device and releasing them into the urinary bladder. 44. The method according to any one of Claims 25 to 43 further comprising imaging the urinary bladder with a system for imaging the urinary bladder associated with the intravesicular device.

45. The method according to any one of Claims 25 to 44 further comprising immobilizing the intravesicular device at a desired location in the bladder.