CN111683599A - Device and method for sensing bladder fullness - Google Patents

Abstract

Embodiments of the present invention provide bladder fullness monitoring systems and related methods for performing such monitoring. A system includes a controller and an active optical sensor attached to a bladder of a patient. The sensor emits light onto the bladder and also detects light reflected from the bladder to produce an output signal indicative of the amount of emitted light reflected back to the detector. The controller is coupled to the optical sensor to receive and interpret the output signal, for example, to determine when the bladder is full. The controller is operably coupled to a urination control device that uses the output signal to trigger urination by a patient who has lost the ability to urinate by oneself. Some embodiments are particularly useful for monitoring bladder fullness in a patient who has lost bladder perception and/or active micturition ability and relies on a micturition control device to facilitate micturition.

Description

Device and method for sensing bladder fullness

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application No.62/609,090 entitled "device and method for sensing bladder pressure" filed on 12/21/2017 (attorney docket No. icub.p054p), which is incorporated herein by reference for any purpose.

Technical Field

Embodiments of the present invention relate to medical devices and methods, and more particularly to a system and method for sensing bladder fullness.

Background

Many diseases result in a loss of a patient's ability to autonomously control bladder function. Most often, patients with spinal cord injuries lose not only the ability to autonomously control urination, but also the ability to sense when the bladder is full. Such patients often have to use catheters, such as foley catheters, for extended periods of time, which extend through the urethra of the patient until the end section of the catheter reaches the bladder, where it can take in urine and cause the bladder to urinate. However, urinary catheters have a number of disadvantages. In particular, the use of urinary catheters presents a continuing risk of infection to the patient, as such catheters can introduce contaminants, cause injury or fail to adequately empty the bladder. In addition, catheters are often drained into bags that must be carried away by the patient when the patient leaves the home or treatment site. Patients often resist using catheters, thus increasing the risk of oliguria and infection.

The problems associated with using a urinary catheter are exacerbated for patients suffering from spinal cord injuries. For example, patients need frequent changes of foley catheters. For patients suffering from spinal cord injuries, urinary catheter replacement (if possible) is a very difficult and sensitive manual task.

Various attempts have been made to address certain deficiencies of urinary catheters. For example, pudendal nerve stimulation systems allow patients and their caregivers to selectively stimulate the pudendal nerve to control bladder urination. However, such pudendal nerve stimulation systems do not detect bladder fullness and therefore do not alert patients that their bladder is full. For those patients who lose the ability to sense when the bladder is full, conventional pudendal nerve stimulation systems increase the risk that the patient may wait too long for the bladder to urinate, thereby increasing the risk of infection. The inability of conventional pudendal nerve stimulation systems to detect filling is highly problematic because the frequency between patient bladder fillings may vary significantly for a number of reasons that the patient may not be aware of (e.g., the patient's recent fluid intake, hydration level, and/or diet).

Disclosure of Invention

Various embodiments of the present invention provide a bladder monitoring system for providing real-time information regarding the fullness and/or status of a patient's bladder. The system may include a sensor device and a controller. The sensor device can be attached to the outer wall of the bladder without piercing the inner wall of the bladder. By not being disposed within the bladder or piercing the inner wall of the bladder, the sensor device may reduce the risk of infection associated with conventional methods for measuring bladder pressure or filling.

In many embodiments, the sensor device may include a light emitter and a detector. The light emitter may be positioned to emit light at an outer wall of the bladder, and the detector may be positioned to detect emitted light reflected from the outer wall of the bladder. Further, the sensor device may generate an output signal indicative of the amount of reflected emitted light. The controller may be operatively coupled to the sensor and may include logic to determine the fullness of the bladder based on the output signal of the sensor device. As such, the bladder monitoring system is particularly useful for patients who are: patients who lose the ability to sense bladder fullness and/or the ability to urinate autonomously due to spinal cord injury or other disease that affects the function of one or more of their spinal cords, pudendal nerve, or other neural pathways involved in the process of urination.

In some embodiments, the controller may be configured to notify the patient (e.g., mobile phone notification) upon determining that the fullness of the bladder exceeds the threshold. Additionally, the controller may be configured to cause the associated urination control device to initiate urination. In some variations, the controller may be integrated with the urination control device, or separate from the urination control device.

In other embodiments, the sensor device may determine the concentration of a chromophore in the bladder fluid of the patient. In such embodiments, the sensor device may emit light in a plurality of wavelength ranges onto the bladder wall of the patient, and may detect light scattered by the bladder fluid for each respective wavelength range. Changes in chromophore concentration for each respective wavelength range from one another can be determined and monitored by the controller, for example to detect changes in color of urine collected by the bladder.

A major advantage provided by certain embodiments over other sensor technologies is that such embodiments can determine bladder volume using an optical sensor that is positioned within the bladder without being catheterized, that is, the optical sensor need not be connected to a foley catheter or similar device that remains in the patient's urinary tract for an extended period of time (which is advantageous because it reduces the risk of infection associated with foley catheters). Rather, in various embodiments, the active optical sensor may be attached directly to the bladder wall (e.g., using sutures or other attachment means known in the medical arts). Additionally, according to some embodiments, the optical sensor may be implanted in an associated electrical stimulation device or system configured to provide electrically induced urination, whereby the patient does not require any other action to function.

Some embodiments may also connect the optical sensor to the bladder through various alternative configurations. In certain embodiments, the optical sensor may be sutured to the outer surface of the bladder wall, thereby eliminating the need to puncture or penetrate the bladder wall. Such an embodiment can avoid the risk of infection or mineralization (e.g., deposit of minerals leading to formation of stones in the bladder) that can occur from electrodes or other sensors that need to pierce the bladder wall. The optical sensor may also be configured to be sutured to a single point or multiple points on the surface of the bladder during implantation in order to reduce trauma or injury to the bladder.

Some embodiments are particularly useful for monitoring and providing information on bladder fullness in a patient from: patients who lose the ability to sense bladder fullness and/or the ability to urinate autonomously due to spinal cord injury or other disease that affects the function of one or more of their spinal cords, pudendal nerve, or other neural pathways involved in the process of urination. Since the optical sensor does not require a high voltage or magnetic field to function (based on the emission and collection of scattered light), it can be powered by a low voltage permanent battery that can be configured to be recharged by inductive coupling with a charging device placed on or near the surface of the abdomen.

For a fuller understanding of the nature and advantages of the present invention, reference should be made to the following detailed description taken together with the accompanying figures. The drawings show, by way of illustration, embodiments of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

Drawings

FIG. 1A shows one example of a bladder monitoring system according to one or more embodiments of the invention.

FIG. 1B shows a schematic pattern of light scattering for the exemplary bladder monitoring system of FIG. 1A.

FIG. 2 shows a graph of electrical signals versus bladder fill time for an exemplary bladder monitoring system according to FIG. 1A.

FIG. 3A shows one example of a sensor for monitoring the filling degree of a patient's bladder.

FIG. 3B shows one example of a stitched edge for a sensor such as that shown in FIG. 3A.

Fig. 4A-4H show various examples of sensors for detecting filling of a patient's bladder.

Fig. 5A shows an experimental device for monitoring bladder filling according to one or more embodiments.

Fig. 5B shows an experiment for determining the difference in spacing between different channels in an experimental sensor.

FIG. 6 shows a graph of measured photodiode voltage versus bladder fill time, showing the response of a bladder monitoring system using the sensor in FIG. 5B.

FIG. 7 shows a graph of the mean and standard deviation of the delta (Δ) for each channel of the sensor of FIG. 5B.

Fig. 8A and 8B show in vivo test setup in pigs for exemplary sensors as shown in various embodiments above for a pig's bladder.

Fig. 9 shows a plot of measured photodiode voltage versus bladder fill time as shown in the example of fig. 8A and 8B.

FIG. 10 shows an exemplary method for monitoring the filling degree of a patient's bladder.

FIG. 11 shows an exemplary method for determining the relative concentration of a chromophore (e.g., bacteria or blood) present in a patient's bladder fluid.

Detailed Description

Embodiments described herein include devices, systems, and methods for detecting and providing information about bladder fullness in a patient. Some embodiments include an optical-based sensor system for measuring and providing real-time information related to the filling of a patient's bladder, for example, based on bladder distension caused by urine volume.

The term "about" as used herein means within ± 10% of the stated property, dimension, or other value, more preferably within ± 5% of the stated value. Further, the term "substantially" as used herein means within ± 10% of the described property or mass, more preferably within ± 5% of the described value.

Some embodiments include sensors for continuously monitoring the degree of filling and/or signs of bladder filling in a patient, so as to initiate urination (also known as urination) in patients who have lost the ability to control and/or sense bladder filling from an autonomous bladder, such as patients suffering from spinal cord injury. In some embodiments, the bladder monitoring system is coupled to or integrated with the voiding control device such that the bladder monitoring system can generate a voiding trigger for the voiding control device.

The embodiments described herein provide a bladder monitoring system that can respond to the fullness of the bladder, rather than to the timed intervals provided by some conventional methods. Among other benefits, the described embodiments better accommodate factors that may affect the fullness of a patient's bladder (e.g., hydration), thereby avoiding the risk of unduly lengthening the time interval between patient urination while providing greater convenience and efficiency.

Embodiments described herein provide a bladder monitoring system for monitoring the fullness of a patient's bladder and providing feedback to the patient indicating when the patient's bladder should be voided. The bladder monitoring device according to embodiments may be beneficial for urinary function in patients suffering from various types of diseases. For example, for patients who use a urinary catheter (e.g., a foley catheter) to void the bladder but lack the ability to detect bladder fullness (e.g., a spinal cord injured patient), an exemplary bladder monitoring system can detect when their bladder should be voided and, in at least some aspects, can optimize the frequency between voiding of a patient's bladder to reduce the likelihood of infection. For patients using pudendal nerve stimulation systems, the bladder monitoring system described above may provide notification to the patient and to the caregiver. Still further, the exemplary bladder monitoring device may be used to trigger a pudendal nerve stimulation system to cause a patient's bladder to void.

Fig. 1A and 1B illustrate an exemplary bladder monitoring system in accordance with one or more embodiments. The exemplary bladder monitoring system 100 includes an optical bladder volume sensor ("BVSD") 110, a controller 130, and a communication interface 140. BVSD110 may be positioned within the patient so as to be attached to or near the patient's bladder 101. BVSD110, when positioned, may generate output signal 111, which output signal 111 may be interpreted by controller 130 as a measure of bladder volume. To generate output signal 111, BVSD110 includes an active optical sensor capable of emitting light and detecting reflections. In some embodiments, the output signal 111 may be in the form of a voltage signal, wherein the value of the voltage signal is indicative of a bladder volume level or measurement. Additionally or alternatively, the output signal 111 may be expressed as a pattern or other characteristic that can be interpreted as a bladder volume measurement.

Controller 130 may be communicatively coupled to BVSD110 to receive output signal 111. In some embodiments, controller 130 is implanted in the patient in operable proximity to BVSD110 (e.g., under the patient's skin). In such embodiments, controller 130 may be directly connected to BVSD110 to receive output signal 111 (e.g., via communication cable 109). In other variations, controller 130 may be wirelessly coupled to BVSD110 to receive output signal 111. The controller 130 may interpret the output signal 111 and generate a corresponding output (shown as controller output 131) that may be reacted to, for example, trigger or cause the patient, caregiver or associated voiding control apparatus to void the bladder 101. In various embodiments, output 131 may be transmitted to communication interface 140, which communication interface 140, in turn, sends or transmits the output to, for example, an associated output device 152 (e.g., a notification device with a light or speaker), a mobile device 154 (e.g., to notify a patient or caregiver), or an associated urination control apparatus 156. In the latter case, output 131 may act as a trigger for associated urination control device 156. Additionally, although particular embodiments are described in which controller 130 is positioned inside the body, in some variations, controller 130 may be positioned outside the body of the patient. One example of a micturition control device 156 is described in U.S. patent application No.15/410,692 entitled "patient-enabled bladder control system and method," which is incorporated by reference herein in its entirety for any purpose.

In other variations, controller 130 may be indirectly coupled to BVSD110 to receive output signal 111. For example, BVSD110 may transmit output signal 111 directly to communication interface 140, which in turn transmits output 111 to controller 130. In such embodiments, an electrical connection (e.g., a cable) may extend between BVSD110 and communication interface 140, and additional connections (e.g., a cable, a wireless connection) may extend between communication interface 140 and controller 130. In such embodiments, controller 130 may be located outside of the patient's body, while communication interface 140 is located inside of the patient's body (e.g., under the skin).

Additionally, although some embodiments describe controller 130 as a separate device, in some variations, some or all of the functionality of controller 130 may be integrated with BVSD 110. For example, in some embodiments, BVSD110 may include microcircuits and/or integrated logic circuitry for interpreting the raw sensor output of BVSD 110. Additionally or alternatively, BVSD110 may also include a transceiver to wirelessly communicate with controller 130 connected to communication interface 140, or with controller 130 positioned outside of the patient's body.

Upon receiving the output signal 111 (or a corresponding signal from the intermediary device), the controller 130 may generate an output 131 indicating the quantification of the bladder volume. In some embodiments, the output of the controller 130 is binary to indicate one of "full" or "not full". In other variations, the output 131 of the controller 130 may indicate the filling degree of the patient's bladder 101 (e.g., "empty," "partially filled," "filled," and "very filled"). Additionally, in other embodiments, the output of the controller 130 may be in the form of a score, such as from 1 to 10, indicating the fullness of the bladder.

According to some embodiments, BVSD110 is configured to be connected or attached to the outer wall 102 of bladder 101. When attached, the position of BVSD110 relative to bladder 101 may be constant (e.g., BVSD110 may move with the volume of the bladder, but remain in substantially the same position relative to bladder 101).

In some variations, BVSD110 may be positioned a distance from the outer wall 102 of the bladder. Moreover, in other variations, BVSD110 may be positioned within bladder 101, on the inner wall 104 of the bladder, or near the inner wall 104 of the bladder.

In embodiments where BVSD110 is attached to the outer wall 102 of bladder 101, BVSD110 may comprise at least a suture opening. The suture opening may receive a suture for securing BVSD110 to the outer wall 102 of bladder 101. In some embodiments, the suture opening is sized to receive a suture of a size (e.g., across a diameter) sufficient to prevent penetration or puncture of the outer wall 102 of the bladder. In some variations, the suture opening may alternatively receive a suture for attaching BVSD110 to the inner wall 104 of bladder 101. Further, in some embodiments, BVSD110 can include a base structure, thickness, or surface 105 shaped to be attachable to the outer wall 104 of the bladder. The substrate surface 105 may be, for example, smooth and/or coated to avoid irritation. Additionally, the substrate surface 105 may be configured to facilitate or allow sensing from within the BVSD 110. For example, a portion of the substrate surface 105 may be translucent to facilitate light propagation from the light emitter 114 and light detection by the detector 112. By attaching BVSD110 to outer wall 102, BVSD110 may have a relatively unobstructed sensing view of bladder 101 without tissue, fluid, or dynamic particles that would cause measurement inaccuracies.

In the embodiment shown in fig. 1A, controller 130 is implanted to be connectable to BVSD110 via a wire or harness of cable 109 (e.g., an insulated cable). Controller 130 may include a microprocessor, integrated circuit, or other logic circuitry for interpreting output signal 111 of BVSD 110. In some variations, controller 130 may also include a separate or integrated power controller for controlling the propagation of light through BVSD 110.

In some embodiments, controller 130 receives electrical output from BVSD110 when the patient's bladder 101 is in an empty state and a full state. Changes in the volume of the bladder 101 can be reflected by changes in the electrical characteristics of the output signal 111 for the respective empty and full states and intermediate states. In some embodiments, changes in bladder status may be reflected by changes in the voltage level of the output signal 111. The change in the voltage value may also be correlated to a change in the volume of the bladder 101. For example, controller 130 may determine that bladder 101 is full when the percentage change in electrical output from BVSD110 exceeds a predetermined threshold. In other embodiments, additional thresholds may be used to mark additional thresholds. In certain embodiments, the electrical output from BVSD110 for empty and full states of the patient's bladder 101 may also be used to calibrate the readings taken by BVSD 110.

According to some embodiments, the electrical output is derived from the photocurrent generated by the photodiode (e.g., light detector 112) of BVSD 110. The photodiode may respond to the detected light by generating a photocurrent, which in turn may develop into a sensing potential, which in turn is related to the filling degree of the bladder 101. The predetermined threshold may be based on a percentage change in the electrical output of BVSD110 between the bladder volume displaying "empty" and the degree of full (e.g., half full, etc.).

In some embodiments, controller 130 is capable of interpreting output signal 111 of BVSD110 as a measure of the sum of one or more light scattering values for various components of bladder 101 (e.g., cells comprising the lumen of bladder 101, mucosa, submucosa, muscularis layer, serosa, adventitia, interstitial regions between cells, etc.). The measurement of the light scattering value of the bladder 101 may vary depending on the filling degree of the bladder 101. For example, the one or more light scatter values may be related to the filling degree of the bladder 101, and more particularly, to the thickness of the bladder wall. In particular, as the bladder becomes full, the bladder wall stretches, thinning the cell layer and interstitial regions between cells. As the bladder wall stretches, changes in the bladder wall affect the amount of scattered light relative to the reflected light, more scattering meaning less reflected light and a decrease in the output signal 111. However, embodiments of the present invention further provide that the amount of reflected light measured as between full and empty bladder states may include contributions due to different physiological changes, which may be conflicting contributions or may be combined contributions. For example, while the inflated bladder 101 may cause more of the emitted light to scatter, the nature of the volume expansion, the area from which the emitted light is reflected, and/or other physiological changes may cause scattering that may cause the emitted light to be reflected indirectly back to the detector 112 (e.g., light escapes at multiple locations in the inner wall 102 of the bladder). Thus, the difference in output measurements between a full bladder and an empty bladder establishes a range or increment (herein "Δ") from which the collected measurements can be estimated during real-time monitoring of bladder fullness. In some embodiments, the range of values of the detected amount of light may be considered a scale indicator of bladder volume. For example, a larger bladder volume may result in less light being detected (and thus, a smaller photovoltaic voltage generated by the detector 112). In other variants, the range of values of the detected amount of light may be pattern matched, for example to address the following: the increase in bladder volume results in the emission light reaching a local minimum inflection point followed by a process of increased light detection values due to the amount of light scattering that is indirectly reflected back to the detector 112. This situation may arise from such physiological conditions as: this physiological condition may result in a light scatter amount that is indirectly reflected back to the detector 112 that is equal to or greater than the light scatter amount that would cause the light to deviate from the detector 112. As shown in such embodiments, the sensed optical characteristic produced by the reflected light may vary in relation to the volume of the bladder, and thus in relation to the filling degree of the bladder. Furthermore, the sensed optical characteristic may be related to other conditions, such as a condition of a change in elasticity (e.g., a decrease in elasticity) of the bladder wall.

In many embodiments, the system 100 may operate under the following assumptions: the sensed optical characteristic produced by the reflected light may vary in a manner related to the relative thickness of the bladder wall, which in turn is indicative of the volume of the bladder 101. In some cases, a change of about 30% in the electrical output received by controller 130 (e.g., the magnitude of output signal 111 from BVSD 110) may translate to a change of about 400mL of bladder fluid volume. As noted above, other changes in electrical output and their corresponding changes in volume have been observed, and embodiments suggest that alternative correlation techniques may be employed to match changes in electrical output to bladder fullness and/or other physiological changes.

Upon determining that the percentage change in electrical output received by the controller 130 exceeds the predetermined threshold, the controller 130 may generate the output 132, for example, to signal the communication interface 140 to notify the patient or caregiver of the degree of filling of the bladder (e.g., via the notification device 152 or the mobile device 154). Additionally, the controller 130 may continue to monitor the bladder 101 to detect when the output signal 131 indicates bladder emptying (e.g., the output signal 131 reaches a minimum threshold). In response to detecting bladder emptying, the controller 130 may also provide a notification to the notification device 152 and/or the mobile device 154 to notify the patient or caregiver when the bladder is empty to an acceptable residual volume (e.g., empty, nearly empty, etc.) so that manual voiding may be stopped.

Additionally or alternatively, the controller 130 may generate the output 132 to trigger the micturition control device 156 to stimulate micturition (e.g., using a surrogate implant for signaling the relevant nerve of the patient). Additionally, the controller 130 may continue to monitor the bladder 101 to detect when the output signal 131 indicates that the bladder 101 is empty. For example, when the output signal 131 reaches a threshold related to voiding of the bladder 101, the system 100 may trigger the voiding control device 156 to cease stimulation of the bladder 101. In this way, based on feedback from BVSD110 to start and stop bladder 101 urination, system 100 can create a closed loop system for regulating the degree of filling of bladder 101. Further, in some embodiments, upon determining that a percentage change in the output received by the controller 130 exceeds a predetermined threshold, the controller 130 may cause the associated implant 140 to induce urination.

In some variations, the system 100 may be used as a diagnostic tool to determine the presence of abnormal levels of bacteria, blood, or proteins in a patient's urine (e.g., such as may be caused by urinary system infection, kidney disease, etc.). According to some embodiments, the system 100 may be configured to characterize the relative concentration of bacteria, proteins, blood, or other chromophores present in the bladder 101 and/or urine within the bladder 101. For example, system 100 may be configured to perform spectral analysis for detection by tuning BVSD110, for example, to operate in the ultraviolet range where bacteria and proteins have the highest light absorption (e.g., <400nm wavelength). In other embodiments, for example, the system 100 may be configured to tune the BVSD110 to a wavelength range that includes the accepted absorption peaks of oxyhemoglobin and deoxyhemoglobin (e.g., between 532nm and 585 nm) to detect the presence of blood in the fluid of the bladder 101. In this way, BVSD110 can detect any color change in the fluid contained within bladder 101, or any color change in the relative chromophore content in the tissues of the bladder wall.

Fig. 1B illustrates an embodiment of a BSVD 110 operating on a patient's bladder 101 as part of a bladder monitoring system 100, according to one or more embodiments. BVSD110 comprises a light source or emitter 114 and a light detector 112, wherein the light emitter 114 emits light onto the outer wall 102 of the bladder and the detector 112 is positioned to detect the emitted light reflected from the bladder 101. In some embodiments, BVSD110 may operate such that light emitted from light emitter 114 may penetrate to various depths and/or internal features (e.g., internal walls) of bladder 101 before most of the light is scattered or reflected back to detector 112. In some embodiments, the amount of emitted light reflected from the interior of bladder 101 and then detected by detector 112 may form the basis of output signal 111 generated by BVSD 110. Embodiments of the present invention provide that, in some cases, the reflected light may include contributions from light scattered but reflected indirectly back to the detector 112, such as emitted light that is initially scattered within the bladder 101 but then undergoes a series of deflections back to the detector 112. Conversely, the difference in the amount of emitted light relative to the amount of detected light may include light passing through the bladder 101 and/or light scattered or deflected away from the detector 112. Further, in some embodiments, the controller 130 may operate in a configuration in which: the filling degree of the bladder 101 is proportional and inversely proportional to the amount of emitted light reflected back to the detector 112. Thus, the output signal 111 of the BVSD110, which may be based on the amount of light detected by the detector 112, may also be inversely proportional to the filling degree of the bladder 101.

In various embodiments, BVSD110 may operate such that light emitter 114 emits light to a target area within bladder 101. Operation of BVSD110 may be modal, such that the depth and direction of emitted light causes at least some of the emitted light to be reflected at the target area. As shown in the embodiments, by selecting a target region for directing the emitted light (e.g., using the direction, intensity, and/or wavelength characteristics of the emitted light), different types of information about the patient's bladder 101 may be determined, including information related to the fullness of the bladder 101.

In the first mode, the light emitter 114 directs emitted light towards the region (r) between the outer wall 102 and the inner wall 104 of the bladder. When the light emitter 114 emits light toward the target area, there is a positive and negative correlation between the amount of light reflected back to the detector 112 and the filling degree of the bladder 101 (e.g., caused by stretching of the bladder 101 and/or thinning caused by its increased volume).

In the second mode, the light emitter 114 directs the emitted light to a region that coincides with the distal inner wall of the bladder 101. In this mode, the light emitted by BVSD110 may not pass through any fluid remaining within the bladder 101, at least initially. In this way, the controller 130 may determine a time-of-flight measurement based on light reflected back from the distal wall. For example, the time-of-flight measurements may be used to calculate the distance between the proximal wall (e.g., 102) and the distal wall (e.g., 106) of the bladder 101 relative to the BVSD 110. Additionally or alternatively, the time-of-flight measurements may provide a baseline that may be used as a basis for comparison when the bladder 101 is inflated with fluid. Thus, in some embodiments, the calculated distance may be input as part of the calculation used to determine the bladder volume. For example, during initial filling (e.g., filling a quarter), light passing through the distal wall of the bladder 101 may cause a sharp drop in the output signal 111 of BVSD110, since the value of the light detector 112 may reflect, for example, a decrease in intensity due to an increase in the travel distance of the light (e.g., as the bladder 101 fills, the distance between the proximal wall 102 and the distal wall 106 increases, causing the reflected light to travel farther in reflection, with greater loss of intensity). As the bladder 101 continues to fill and the level of the bladder 101 rises above the position of the light detector, the reflected light may scatter off of the detector 112 and thus be undetectable, thereby further reducing the electrical output of the BVSD 110. Additionally, the presence of the fluid medium may reduce the amount of light scattering that is indirectly reflected back to the detector 112.

In a third or alternative mode, the emitted light may be directed to the submerged area (c). The detector 112 may indicate light scattering (e.g., by loss of light reflected back to the detector), which detection may be related to an optical mismatch between the proximal wall (e.g., 102) or the distal wall 106 and the liquid contents of the bladder 101. The light sensed in this mode may be proportional to the difference in refractive index between the bladder wall tissue and the liquid contents of the bladder 101. The controller 130 may be associated with information indicative of a difference in refractive index of the state of the patient's bladder 101, including the filling degree of the bladder 101.

In the fourth mode, the light is guided to the region (r) where it can be scattered by solids present in the liquid of the bladder. In this mode, the light detected by BVSD110 may be indicative of the concentration of proteins, bacteria, hemoglobin and any other chromophores present in the fluid of the bladder. Although this model cannot be directly applied to determining bladder volume, it may provide other diagnostic features (e.g., urinary tract infection, kidney disease, etc.) as will be described in more detail below.

In some variations, a staining contrast agent may be introduced into the wall of the bladder 101 at the implantation site (e.g., the area below BVSD 110). By introducing a staining contrast agent, the light scattering coefficient of the cells and interstitial regions in the bladder 101 may be increased and result in a corresponding increase in the changes measured for the expression of "empty" and "full" of the bladder 101. The dye contrast agent may be introduced, for example, by tattooing the implanted area with indian ink (e.g., Spot, Endomark, etc.), indocyanine green (e.g., cardiogen), etc.

Fig. 2 is a graph of electrical signal of BVSD110 as a function of time when the bladder becomes full. As shown in fig. 1A, 1B, and 2, BVSD110 produces an electrical output 111 as a voltage output, where the voltage value reflects the amount of emitted light reflected back from a target region (e.g., the outer wall) of the bladder. In some embodiments, the controller 130 implements logic that correlates the state of bladder being full to the amount of reflected light that is reflected back to the detector 112, which is an inverse relationship. Additionally or alternatively, controller 130 implements logic that relates light scattering to bladder fullness, where, for example, the amount of light scattering is indicated by the intensity of signal emission from BVSD110, such that the signal intensity is inversely related to the amount of scattering. In some embodiments, output signal 111 of BVSD110 may be in the form of a voltage output, such that the voltage level of output signal 111 is inversely related to the filling degree of the bladder. As shown in the graph in fig. 2, output signal 111 of BVSD110 decreases as bladder volume changes over time between an empty bladder state and a full bladder state. For example, in fig. 2, output signal 111 of BVSD110 decreases from about 0.011V to about 0.008V, indicating an increase in bladder volume of about 33%.

Fig. 3A shows one embodiment of BVSD for monitoring bladder filling. BVSD300 includes light source 310 (also referred to herein as light emitter 310), light detector 320, backing 330, optical window 340, light barrier 350, and stitching edge 360. Sidewalls 302 of BVSD300 may be formed of any biocompatible material (e.g., titanium) that helps provide a hermetic seal for light source 310 and light detector 320.

The light source 310 may correspond to any light source (e.g., a light emitting diode) that is capable of emitting light when activated. Additionally or alternatively, light source 310 may be tuned to any wavelength (e.g., ultraviolet, visible, near infrared, etc.). In some embodiments, BVSD300 utilizes infrared light wavelength emission to determine the change between empty and full bladder. Additionally, the light source 310 may include one or both of an incoherent light source and a coherent light source (e.g., an LED, a laser, etc.). For example, in some variations, a coherent light source may be used to provide greater tissue penetration, such as penetration of the distal wall of the bladder (e.g., 106 in fig. 1B).

The light detector 320 may correspond to any device used to detect light and convert the light into an electrical output (e.g., a photodiode voltage). For example, light emitted by the light source 310 may be scattered by bladder tissue and detected by the light detector 320, and the light detector 320 may then generate a photocurrent proportional to the increase in volume of the bladder.

As shown in fig. 3A or fig. 4A-4H, in some variations, light source 310 and/or light detector 320 may be mounted and positioned on optical window 340/440, or on a surface of BVSD300 that is not in contact with tissue (e.g., as shown by backing 330) (e.g., positioned opposite optical window 340/440). In some variations, the light source 310 may be mounted on the backing 330 and the light detector 320 may be mounted on the optical window 340, or vice versa.

The backing 330 may be formed of any material suitable for mounting the light source 310 and the detector 320 in pairs. The backing may also be formed of a material (e.g., a ceramic material, etc.) that may form a hermetic seal for the various components of the BVSD300 when the BVSD300 is attached to the bladder. Backing 330 may also include vias 332 for routing wires 312/322 from the interior or package space within BVSD300 to an area outside BVSD300 to facilitate direct or indirect connection to a controller or other device.

Referring now to fig. 3A, optical window 340 may be formed of any optical material (e.g., sapphire) capable of providing a transparent medium to transmit light to/from BVSD 300. Optical window 340 may be configured to allow a range of wavelengths (e.g., ultraviolet, visible, near infrared, etc.) used by BVSD300 to propagate. For example, in one variation, BVSD300 may utilize light in the ultraviolet range (e.g., <400nm), where bacteria and proteins have the highest optical absorbance, in order to perform spectroscopic analysis of the liquid contents in the bladder (e.g., to determine the relative concentration of chromophores present in the bladder).

According to many embodiments, the optical window 340 may be configured as a rigid structure, e.g., comprising a flat structure. In some variations, the optical window 340 may be a curved or flexible structure configured such that the placement and/or quality of the optical window 340 is substantially flush with (or fully compressed against) the outer wall of the bladder. The arrangement of the optical window 340 flush with the outer wall of the bladder can prevent or at least reduce fluid introduction between the tissue contacting surface of the BVSD300 and the outer wall of the bladder. The introduction of liquid between the tissue contacting surface of BVSD300 and the bladder wall can lead to inaccurate measurements, since the optical properties of the liquid may not change as the bladder expands, which may lead to changes in bladder elasticity that cannot be detected.

The flag 350 may include any material (e.g., opaque material, photochromic material, etc.) configured to reduce or prevent light from propagating directly between the light source 310 and the light detector 320. In the embodiment of fig. 3A, flag 350 is in contact with optical window 340, but not backing 330. In some configurations, flag 350 may be configured to contact optical window 340 and backing 330. In other configurations of BVSD300, light barrier 350 may extend into optical window 340, at the tissue contacting surface of BVSD300 (as shown in fig. 4C and 4H), or may contact optical window 340 without extending into optical window 340 (as shown in fig. 3A, 4D, and 4G). In other variations, flag 350 may extend only partially into optical window 340. Additionally, in other variations, light barrier 350 does not contact optical window 340 of BVSD 300.

Fig. 3B illustrates one embodiment of a stitched edge 360 of BVSD 300. The suture rim 360 includes a suture opening 362 configured to provide a maximum amount of freedom of bladder tissue in the implantation area (e.g., bladder tissue below BVSD 110/300) so as not to impede or prevent the biaxial stretching of bladder tissue that would occur when normally filling the bladder. In one variation, BVSD300 includes four pairs of suture openings 362, where 4 suture knots may be tied, respectively, along suture path 364, in order to secure BVSD300 to the outer wall of the bladder (e.g., 102). Such embodiments with suture openings 362 arranged in pairs (e.g., 2, 3, 4, 5, etc.) can provide the following advantages: the suture when attaching BVSD300 to the bladder minimizes, or at least does not impede or hinder, the stretching of the bladder. The paired arrangement of suture openings 362 allows the bladder to expand naturally (e.g., as if no BVSD300 were present) as the bladder may continue to expand, without unnatural size limitations or patient pain. In other variations, BVSD300 is coated or impregnated with growth factors known in the art to facilitate encapsulation, e.g., cell and/or protein encapsulation, between BVSD300 and the outer wall of the bladder.

In some variations, BVSD300 may be naturally encapsulated by exposure to the patient's tissue. For example, natural encapsulation may be achieved when BVSD300 is connected or attached near or at a location on the patient's bladder for a time sufficient to allow scar tissue and/or protein deposits to naturally develop in the area surrounding the patient's bladder, resulting in attachment of BVSD300 to the bladder wall. The use of this natural process may provide additional or alternative attachment mechanisms for BVSD300 relative to the patient's bladder wall. Additionally, in some embodiments, the use of natural processes may replace the initial attachment mechanism over time. For example, BVSD300 may be initially attached to the bladder wall using a suturing tool, and then the natural process is allowed or initiated within the patient's body to substantially attach BVSD300 to and/or contact the outer wall of the patient's bladder.

Fig. 4A-4H illustrate alternative examples of BVSDs, in accordance with one or more embodiments. In the depicted embodiment, BVSD 400 includes light emitter 410 and light detector 420, which are mounted to each other in an alternative configuration. In the embodiment of fig. 4A-4D, the light source 410 and the light detector 420 are mounted on a backing 430. In the embodiment of fig. 4E-4H, the light source 410 and the light detector 420 are mounted on an optical window 440.

In fig. 4A, a pair of light sources 410 and light detectors 420 ("pair 410/420") are mounted on backing 430 in an "endless" configuration with the pair 410/420 exposed. In contrast to fig. 4A, fig. 4B-4D show an alternative configuration of BVSD 400 that would 410/420 pair be hermetically sealed. In fig. 4B, the device is configured in a "single-port" configuration in which the 410/420 pair is hermetically sealed between backing 430, optical window 440, and wall plate 402. Fig. 4C includes a "two-port" configuration in which the light barrier 450 is configured to prevent light from propagating directly between pairs of 410/420.

The flag 450 may include alternative configurations, such as featuring the length of the flag 450. In the embodiment of fig. 4C, the flag 450 is configured to extend from the backing 430 to/through the optical window 440. In the embodiment of fig. 4D, the flag 450 extends from the backing 430 to the optical window 440, but does not extend into the optical window 440. In other variations (not shown here), the flag 450 may extend partially into the optical window 440. In other embodiments, as shown in fig. 3A, flag 350 may extend from the optical window, but may not extend completely to backing 330.

In the embodiment of fig. 4E-4H, 410/420 pairs may be mounted on optical window 440. In the embodiment of fig. 4E, the 410/420 pairs are configured in a "no port-window coupling" configuration, wherein the 410/420 pairs are exposed to the ambient environment. In the embodiment of fig. 4F-4H, the pair of 410/420 is encapsulated in a protective layer of polymer, epoxy, or any other biocompatible molded encapsulation. In the embodiment of fig. 4F, BVSD 400 is configured in a "no port-window coupling/encapsulation" configuration. In the embodiment of fig. 4G, BVSD 400 comprises a "two-port" configuration, wherein light barrier 450 is configured to prevent light from propagating directly between 410/420 pairs. As described above, the flag 450 can be configured to have various lengths to extend to the optical window 440 (as shown in the embodiment of fig. 4G), or to extend through the optical window (as shown in the embodiment of fig. 4H), among other various lengths.

In the embodiments of fig. 4A-4H, the distance between the light source 410 and the light detector 420 may be fixed. In some variations, the effect of monitoring bladder filling may be improved as the distance between the light source 410 and the light detector 420 is increased: (i) the change between the "empty" and "full" measurements of the bladder may increase; (ii) the signal-to-noise ratio in the signal produced by BVSD 400 may be increased. In some cases, the distance between the light source 410 and the light detector 420 is about 10mm, although other distances are contemplated.

Examples of the invention

Various embodiments of the invention are illustrated below for purposes of explanation, and any embodiment or aspect of the invention is not intended to be limited to a particular example.

Example 1 (in vitro)

This example relates to the in vitro testing of examples using BVSD of explanted porcine bladder.

Experimental setup: fig. 5A illustrates a specific experimental in vitro setup for determining the effect of different spacings between light sources (e.g., light sources or emitters 310, 410, 510) and light detectors (e.g., detectors 320, 420, 520). As shown in fig. 5A, a bladder monitoring system was tested, wherein the system included BVSDs (e.g., BVSDs 300, 400, 500) sutured onto explanted porcine bladder and submerged under water in the bladder water tank. When the infusion pump and pressure sensor are combined to provide a bladder filling rate of 360mL/hr, the power source is configured to provide power to operate the light source of the BVSD and the voltmeter is configured to measure a corresponding electrical signal generated by the light detector (e.g., photodiode) of the BVSD.

Fig. 5B shows an experimental configuration of BVSD 500 for determining whether the separation of a light source and light detector pair is related to the resulting change between an empty bladder and a full bladder. The light source 510 and the plurality of light detectors 520 are mounted on the optical window 540 and separated by the light barrier 550. In the embodiment of fig. 5B, the light source 510 includes an LED (particularly an APT2012SF4C-PRV LED), and a plurality of light detectors 520, each including a photodiode ("PD"), particularly a VEMD1060X01 photodiode, at progressively increasing distances from the LED. For example, in one experimental setup, the distance from the center of LED 510 to the center of PD 520 located in Channel 1 ("Channel 1") was measured to be 2.9 mm; the distance from the center of LED 510 to the center of PD 520 located in Channel 2 ("Channel 2") was measured to be 5.5 mm; the distance from the center of LED 510 to the center of PD 520 located in Channel 3 ("Channel 3") was measured to be 8.2 mm; the distance from the center of LED 510 to the center of PD 520 located in Channel 4 ("Channel 4") was measured to be 10.4 mm.

The experimental setup shown in fig. 5A and 5B provides independent evaluation of the individual LED/PD pairs by sequentially energizing each pair of intervals and sampling the PD voltage for each pair of intervals as saline is filled into the bladder by the infusion pump. Furthermore, each channel is turned on sequentially for 1 second and a corresponding PD voltage sample is taken for each individual LED lighting channel. The first 100 and last 100 samples of the electrical signal recorded for each channel were used to calculate the average change in bladder volume with a fill rate of 360 mL/hr.

As a result: fig. 6 is a graph of PD voltage measured during bladder filling. The graph shows the response of different spacing configurations of LEDs and PDs (corresponding to channels 1-4 shown in fig. 5B) to bladder filling/stretching using the system of the exemplary BVSD. As shown in fig. 6, the bladder volume change becomes larger from channel 1 to channel 4, which is the difference in PD voltage measured over time as the bladder fills. In other words, as the distance between the LED 510 and the PD 520 becomes larger, the change in bladder volume also becomes larger. In addition, fig. 7 shows this phenomenon by the mean and standard deviation of the variation for each channel. It can be observed that the mean and standard deviation are greatest in lane 4 (with PD 520 in lane 4 being configured furthest from LED 510 relative to the other lanes). This result is unexpected in at least two aspects described below.

First, one skilled in the art would expect that the closest LED/PD pair (e.g., channel 1) would produce the largest mean and standard deviation over time when filling the bladder as compared to the other channels. The expected results are based on: when the LED and PD are closer together, the loss of light scattering is less, and when the LED and PD are closer together, the LED and PD are more aligned with respect to the angle of the reflected light from the skin.

Second, previous studies have shown that the intensity of the measured reflected light from an extended skin surface increases in a linear fashion with respect to the increase in skin surface extension. See Federici, J. et al. non-invasive light reflectance technique for measuring soft tissue extension.application optics.1999, 11.1; 38(31):6653-60. In contrast, in the example of the above case, the intensity of the measured light decreases with increasing stretching of the bladder wall (e.g., filling through the bladder) and decreases in a seemingly non-linear manner. Therefore, the experimental results are contrary to those expected by those skilled in the art from experiments performed using examples of BVSD, as they are contrary to the prior art.

Example 2 (in vivo study)

This example relates to in vivo testing of an embodiment of BVSD in a pig model.

Experimental setup: after the humanistic endpoint of another study (independent of the BVSD study), a 35kg pig was obtained in excellent condition according to the gratified animal recycling policy. The porcine bladder was catheterized and connected to a DRE infusion pump set at 420 mL/hr. As shown in fig. 8A and 8B, an incision was made and the BVSD sensor was sutured to the bladder surface. The incision was closed and infusion of saline at a constant rate was initiated. During bladder filling (about 1 hour), the voltage output of the BVSD photodiode across a 10k load resistor was recorded. The sampling rate was 1 sample per second, so 3600 samples could be obtained for a bladder volume filled with 420mL within 1 hour of the duration of the experiment. Data were recorded using keithley dmm used in the bench test.

As a result: as shown in fig. 9, the results showed an average change of 48% and a standard deviation of 0.2%.

FIG. 10 illustrates an exemplary method of monitoring the filling degree of a patient's bladder. One embodiment as shown in the example of fig. 10 may be implemented, for example, using the devices and sensors described for other embodiments, including those described for fig. 1A-9. Accordingly, suitable components for implementing the steps or sub-steps may be described with reference to the elements described with respect to fig. 1A-9.

According to some embodiments, the fullness of a patient's bladder may be monitored using an active optical sensor disposed on an outer wall of the bladder of the patient, wherein the sensor may be used to emit light onto and/or into the wall of the bladder (step 1010). The sensor may include at least one pair of suture openings on a tissue contacting surface of the sensor to allow the sensor to be secured to an outer wall (e.g., 102) of the bladder without piercing an inner wall (e.g., 104) of the bladder. This reduces the risk of infection in some conventional methods of leaving an indwelling catheter or other device in the bladder. The sensor may also include an optical window. Since the efficacy of the optical window may be reduced when the optical window is not directly coupled to the surface of the bladder wall, in some variations, the optical sensor may include up to four pairs of suture openings (e.g., at four corners of a suture edge) to directly couple between the tissue-contacting surface of the device and the outer wall of the bladder, but also to allow stretching of the bladder tissue at the implantation site. Other configurations and other numbers of suture openings are also contemplated.

In addition, the sensor detects light scattered by the outer wall of the bladder (step 1020). In some variations, the sensor may operate over a range of wavelengths that allow for a range of tissue penetration depths. For example, referring to fig. 1B, one wavelength range may only cause light to scatter in bladder tissue of the proximal wall of the bladder (e.g., between 102 and 104), as shown in the first mode. However, another wavelength may cause light to scatter in bladder tissue of the distal wall (e.g., 106) of the bladder, as shown in the second mode.

In the method of fig. 10, the controller causes the associated implant to perform a function when the electrical output of the sensor exceeds a predetermined threshold (step 1030). The electrical output produced by the sensor may be proportional to the amount of light scattered by the bladder, and may be compared to a predetermined range of outputs (e.g., Δ) representative of an "empty" bladder and a "full" bladder. To reduce or eliminate direct propagation of light between the light source and the light detector, which may adversely affect the accuracy of the light scatter measurement, a light barrier may be disposed between the light source and the light detector. In embodiments such as that shown in fig. 3A, flag 350 may extend into optical window 340 to form a portion of the tissue contacting surface of BVSD 300. In the variation shown in fig. 4D and 4G, the flag 450 may extend to contact the optical window 440, but may not extend within the optical window 440 to form part of the tissue contacting surface.

In various embodiments, the controller may be further configured to determine (e.g., via software or hardware) whether a percentage change in the output received by the sensor exceeds a predetermined threshold. In one variation, when the controller determines that the percentage change in electrical output exceeds a predetermined threshold, the controller may cause the associated implant to notify the patient of the degree of filling of the bladder, or may cause the associated implant to initiate urination.

Fig. 11 illustrates an exemplary method for determining the relative concentration of chromophores present in bladder fluid of a patient. Such chromophores include one or more of bacteria (or other unicellular microorganisms), proteins, and blood. The embodiment shown in fig. 11, for example, may be implemented by way of example of devices and sensors as described in the embodiments of fig. 1A-9. Accordingly, suitable components for implementing the steps or sub-steps may be described with reference to the elements described in fig. 1A-9.

Referring to the embodiment of FIG. 11, a sensor located on the outer wall of the bladder may emit light in a first wavelength range and may also detect light scattered by bladder fluid in the first wavelength range (step 1110). For example, the sensor may emit ultraviolet light, with bacteria and proteins having the highest light absorption.

In addition, the sensor may emit light in a second wavelength range and detect light scattered by the bladder fluid (step 1120). For example, the sensor may emit light in the range of 532-585nm, where oxyhemoglobin and deoxyhemoglobin have well-recognized absorption peaks.

A controller coupled to the sensor may determine a ratio of a first chromophore concentration associated with the first wavelength range to a second chromophore concentration associated with the second wavelength range (step 1130). For example, the controller may utilize an algorithm or equation (e.g., beer-lambert law) to solve for the concentration of proteins and bacteria present in the bladder. For example, the controller may utilize the following equation:

wherein, I_λuvWhich represents the current measured by the sensor or sensors,_{protein+bacteria}represents the molar extinction coefficient (known amount) of protein plus bacteria, lambda_uvIndicating the wavelength of the emitted light (known asAmount) of c) and c_{bacteria+protein}Representing the relative concentration ratio of protein to bacteria.

The controller may determine a second concentration of chromophore present in the bladder in a similar manner. For example, the controller may utilize an algorithm or equation (e.g., beer-lambert law) to solve for the concentration of hemoglobin present in the bladder. For example, the controller may utilize the following equation:

wherein, I_λ532-585Representing the current measured by the light sensor,_hemoglobinrepresents the molar extinction coefficient (known quantity) of hemoglobin, lambda_532-585Represents the wavelength (known quantity) of the emitted light, and c_hemoglobinIndicating the relative concentration ratio of hemoglobin.

The controller may monitor the proportion of the change in the first concentration relative to the second concentration (step 1140). Additionally, a third wavelength may be emitted and sensed as a control or baseline concentration. This can be in the near infrared region, which is far from the absorption peaks used in previous algorithms. Thus, a system of 3 equations can be obtained and the relative concentrations of protein/bacteria and hemoglobin can be measured relative to the third control relative concentration.

Conclusion

The embodiments described herein may be extended to individual elements and concepts described herein independently of other concepts, ideas or systems, and embodiments may include combinations of elements listed anywhere in this application. Although embodiments are described in detail herein with reference only to the accompanying drawings, it should be understood that the concepts are not limited to those specific embodiments. Accordingly, it is intended that the scope of the concept be defined by the following claims and their equivalents. Furthermore, it is to be understood that a particular feature described either individually or as part of an embodiment can be combined with other individually described features or features as part of other embodiments, even if these other features and embodiments do not mention the particular feature. Thus, a combination not described should not exclude the right to such a combination.

The foregoing description of various embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be limited to the specific form disclosed. Many modifications, variations and improvements will be apparent to those skilled in the art. For example, the sizing and other aspects of embodiments of the device can be adapted for various pediatric and neonatal applications as well as various veterinary applications. They are also suitable for the urinary tract of men and women. Further, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific devices and methods described herein. Such equivalents are considered to be within the scope of the invention and are covered by the following claims.

Elements, features, or acts from one embodiment may be readily recombined or substituted for those of one or more embodiments or from other embodiments to form numerous additional embodiments within the scope of the present invention. In addition, elements shown or described as combined with other elements may also exist as separate elements in various embodiments. In addition, for any positive statement of an element, property, composition, feature, or step, embodiments of the invention specifically also contemplate the exclusion of that element, value, property, composition, feature, or step. Accordingly, the scope of the invention is not limited by the details of the described embodiments, but only by the appended claims.

Claims (27)

1. A bladder monitoring system comprising:

sensor means fixedly positionable on an outer wall of a bladder without piercing an inner wall of the bladder, the sensor means comprising a light emitter and a detector, the light emitter positioned to emit light on the outer wall of the bladder and the detector positioned to detect emitted light reflected by the outer wall of the bladder, wherein the sensor means is capable of generating an output signal indicative of an amount of the reflected emitted light; and

a controller operatively coupled to the sensor device, the controller including logic to determine a filling degree of the bladder based on an output signal of the sensor device.

2. The system of claim 1, wherein the output signal of the sensor means is indicative of an amount of emitted light scattered by an outer wall of the bladder and therefore not detectable by the sensor means.

3. The system of claim 1, wherein the output signal of the sensor device is indicative of an intensity of the reflected emitted light.

4. The system of claim 1, wherein the controller comprises logic to determine the filling degree of the bladder based on an inverse relationship between the filling degree of the bladder and a magnitude of the output signal of the sensor device.

5. The system of claim 1, wherein the controller is configured to generate an output detectable by the patient upon determining that the degree of filling of the bladder exceeds a threshold.

6. The system of claim 1, wherein the controller is configured to send a notification to a mobile device of the patient upon determining that the fullness of the bladder exceeds a threshold.

7. The system of claim 1, wherein the sensor device comprises at least one pair of suture openings configured to enable attachment of the sensor device to an outer wall of the bladder without piercing an inner wall of the bladder.

8. The system of claim 1, wherein the sensor device is configured to emit light to one or more interior walls of the bladder, the one or more interior walls including a wall proximal to the sensor device and a wall distal to the sensor device.

9. The system of claim 1, wherein the controller is configured to cause an associated urination control device to perform a function when the output signal of the sensor device exceeds a predetermined threshold.

10. The system of claim 9, wherein the function performed by the urination control device includes inducing urination.

11. The system of claim 10, wherein the controller is integrated with the urination control device.

12. The system of claim 10, wherein the controller is independent of the urination control device.

13. The system of claim 1, wherein a spacing between the light emitter and the detector is in a range from about 8.2mm to 10.4 mm.

14. A sensor device for detecting filling of a patient's bladder, the sensor device comprising:

a base surface for securing to an outer wall of the bladder without piercing an inner wall of the bladder;

a light source and a light detector coupled to the base surface, the light source and light detector positioned and configured to emit light onto an outer wall of the patient's bladder and detect light scattered by the outer wall of the patient's bladder such that an amount of scattering correlates with a degree of fullness of the patient's bladder; and is

Wherein the light detector is configured to produce an output related to an amount scattered by an outer wall of the bladder.

15. The sensor device of claim 14, wherein the output is configured to be usable by a controller operatively coupled to the sensor device to determine when the filling degree of the bladder exceeds a predetermined threshold.

16. The sensor device of claim 14, wherein the light source is a light emitting diode.

17. The sensor device of claim 14, wherein the light detector is a photodiode.

18. The sensor device of claim 14, further comprising an optical window, the optical window being formed of sapphire.

19. The sensor device of claim 14, further comprising a flag positioned and configured to prevent direct propagation of light between the light source and the light detector.

20. A method for monitoring the filling degree of a patient's bladder, the method comprising:

positioning a sensor on an outer wall of the patient's bladder, the sensor comprising a light source and a detector;

emitting light from the sensor onto the outer wall of the bladder;

detecting, by the sensor, an amount of light reflected by an outer wall of the bladder and generating an output signal related to the detected amount of light; and

the detected light signal and the inverse relationship between the amount of reflected light and bladder fullness are used to determine the bladder fullness of the patient.

21. The method of claim 20, further comprising:

performing a function in a urination control device associated with the sensor when an electrical output of the sensor exceeds a predetermined threshold, wherein the electrical output of the sensor is related to light scattered by an outer wall of the bladder.

22. The method of claim 20, wherein the urination control device includes a pudendal nerve stimulation device.

23. The method of claim 20, wherein the function comprises sending a notification to the patient.

24. The method of claim 20, wherein the notification comprises information about bladder fullness or information that urination is required.

25. The method of claim 20, wherein the function comprises an electrical activation of urination.

26. A method for determining a chromophore concentration in bladder fluid of a patient, the method comprising:

positioning a sensor on an outer wall of the patient's bladder, the sensor comprising a light source and a detector;

emitting, by the sensor, light of a first wavelength range onto a bladder wall of a patient;

detecting, by the sensor, light of a first wavelength scattered by the bladder fluid;

emitting, by the sensor, light of a second wavelength range onto the bladder wall of the patient;

detecting, by the sensor, light of a second wavelength scattered by the bladder fluid;

determining a ratio of a first chromophore concentration associated with the first wavelength range relative to a second chromophore concentration associated with the second wavelength range; and

the proportion of the change in the first concentration relative to the second concentration is monitored by the controller.

27. The method of claim 26, further comprising detecting a color change in urine collected by the bladder.

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