WO2025024425A2

WO2025024425A2 - Devices, methods, and processes for monitoring urine flow

Info

Publication number: WO2025024425A2
Application number: PCT/US2024/039115
Authority: WO
Inventors: Hani M. WADEI; John SIMCOX; Chris Hile; Jeffrey Cameron Loper
Original assignee: Mayo Foundation for Medical Education and Research; Mayo Clinic in Florida
Current assignee: Mayo Foundation for Medical Education and Research; Mayo Clinic in Florida
Priority date: 2023-07-24
Filing date: 2024-07-23
Publication date: 2025-01-30
Anticipated expiration: 2026-01-24
Also published as: WO2025024425A3

Abstract

This document provides devices, methods, and processes for an implantable urine flow sensor including a first end coupled to a first portion of a uretic stent, and a second end coupled to a second portion of the uretic stent. The implantable urine flow sensor is sized to fit within, and be operable within, an individual ureter.

Description

DEVICES, METHODS, AND PROCESSES FOR MONITORING URINE FLOW

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Serial No. 63/528,566, filed July 24, 2023. The disclosure of the prior application is considered part of the disclosure of this application, and is incorporated in its entirety into this application.

TECHNICAL FIELD

This document relates to devices methods and processes for monitoring urine flow. For example, this document relates to devices, methods, and processes for determining the flow of urine from an individual kidney of a subject.

BACKGROUND INFORMATION

Sensing urine flow within the bladder or within the urethra allows for monitoring urine flow. By measuring the flow of urine, medical professionals can evaluate the presence of any obstructions or complications that may necessitate intervention. This information aids in the diagnosis and management of conditions such as, but not limited to, urinary tract obstruction, and kidney stones.

SUMMARY

This document describes devices, methods, and processes for monitoring urine flow through an individual ureter in a subject (e.g., a human or animal). Monitoring urine flow can include a determination of the flowrate of urine. The flowrate of urine is a measurement of a volume of urine expelled from a kidney over a period of time and is a measurement of how quickly urine is flowing through the urinary system. The improved flow sensors described in this document aim to address a significant problem in urology and kidney transplantation that remains unmet by current technology. While existing technology can successfully detect the flowrate of urine flow within the bladder or urethra, it falls short when it comes to isolating the flowrate of urine production from individual kidneys. This limitation becomes particularly problematic when assessing the function of an individual kidney, such as in the case of a kidney transplant. Presently, there is no viable method to determine if a donor kidney is producing urine without resorting to invasive testing or potentially requiring additional surgery as urine is still being made by the native kidneys. This pressing issue underscores the need for a solution that can accurately and non-invasively monitor the function of an individual kidney especially in the case of kidney transplantation.

Some embodiments of the devices, methods, and processes described herein may provide one or more of the following advantages. First, some embodiments described herein disclose a flow sensor that is sized to fit within a ureter. The compact design of the flow sensor allows the detection of the flow of urine from an individual kidney. In some example embodiments, the flow sensor can be positioned within a ureter to measure the flowrate of urine from a donor kidney. This can provide information about the function of an individual kidney such that interventions can be provided, if necessary. In contrast, the measurement of the flowrate of urine within the urethra or bladder does not provide distinguishing information between urine contributions of each kidney individually. Continuous monitoring of urine flow from an individual kidney through a sensor configured (e.g., sized) to fit in an individual ureter can aid in the timely identification of urinary retention or obstruction, enabling prompt intervention and reducing the risk of associated complications.

Second, some embodiments described herein disclose a flow sensor configured to fit within a ureter and coupled to a stent. For example, stents are positioned in a donor ureter during kidney transplants. The improved flow sensor described herein can be coupled to the stent and positioned in a donor ureter during a kidney transplant. The incorporation of the flow sensor to a stent that is already to be used in a donor ureter during the surgical process of a kidney transplant avoids the additional invasive procedures that could otherwise be necessary. For example, the flow sensor is positioned in the donor ureter with the stent without significant differences in the surgical procedure. Incorporating a urine flow sensor coupled to a stent that was already to be used as part of a kidney surgical procedure (e.g., a kidney transplant) eliminates the need for separate procedures or visits to a medical facility to assess urinary function. This can streamline the patient's postoperative care and potentially reduce healthcare costs. Further, implantation of a urine flow sensor coupled to a stent into a donor ureter during a kidney transplant provides a unique opportunity for real-time monitoring of postoperative urinary function of the donor kidney, allowing for early detection of any complications or abnormalities.

Third, some embodiments described herein include an improved flow sensor device that includes wireless transmission capabilities. The incorporation of wireless transmission capabilities in the improved flow sensor described herein offers the distinct advantage of real-time data transmission, allowing for immediate monitoring and analysis of urinary flow patterns. Further, with wireless transmission, healthcare professionals can remotely access the data collected by the flow sensor, enabling them to monitor patients' urine flow from an individual kidney in real time from a centralized location, without the need for physical proximity. This provides the added benefit of allowing a patient to recover in the comfort of their home and avoid added stress of constant monitoring in a facility. The wireless transmission can provide real-time data transmission to prompt identification of abnormalities or irregularities in urinary flow from an individual kidney, enabling early intervention, thereby improving patient care and outcomes. Additionally, wireless transmission capabilities can allow real-time transmission of data for the seamless integration of urine flow information into electronic health records (EHRs), enabling comprehensive and accurate patient records and facilitating better collaboration between healthcare providers involved in the patient's care.

Fourth, with a flow sensor coupled to a stent in place within a donor or native ureter, the flow device can facilitate long-term monitoring of urine flow from an individual kidney without the need for frequent removal or reinsertion. This is particularly advantageous for patients requiring extended monitoring or those with chronic conditions affecting urinary function and those with urinary obstruction.

One aspect of this document features devices, methods, and processes for monitoring urine flow. In some example embodiments, devices can include, or consist essentially of, an implantable urine flow sensor, including a first end coupled to a first portion of a uretic stent; and a second end coupled to a second portion of the uretic stent, wherein the implantable urine flow sensor is sized to fit within an individual ureter. In some embodiments, the stent is one of an open-ended ureteral stent or a closed-ended ureteral stent. For example, the stent is a double-j stent. In some embodiments, a diameter of the implantable urine flow sensor is less than about 4.2 mm. In some embodiments, the stent further includes an upstream flowcollection unit located at the first end; a downstream flow vent located at the second end; an enclosure located between the upstream flow-collection unit and the downstream flow vent, wherein a urine flow path traverses a lumen of the stent from the first portion, through the enclosure, to the second portion; a needle positioned within the enclosure; and a spring positioned within the enclosure proximal to the second end. In some embodiments, the upstream flow-collection unit gathers the urine expelled from a kidney via the ureter and directs it to the enclosure for measurement.

In some embodiments, the downstream flow vent is configured to maintain a consistent flow of urine and regulate back pressure. In some embodiments, the enclosure is configured to contain the urine collected from the ureter for measurement with the needle and the spring. In some embodiments, the needle is positioned in the enclosure within the flow path and substantially restricting a flow of urine from the first portion of the stent to the second portion of the stent. In some embodiments, the needle has geometry that includes a pointed shape, a blunt shape, or an irregular shape. In some embodiments, the device further includes an electronics unit coupled to the enclosure. In some embodiments, the electronics unit also includes a light emitting unit positioned within the enclosure; and a receiver positioned within the enclosure across from the light emitting unit. In some embodiments, the light emitting unit is a light emitting diode. In some embodiments, the needle is positioned in the enclosure within the flow path and substantially blocks light from the light emitting unit from reaching the receiver when a flowrate of urine is below a threshold.

In some embodiments, a flow of urine through the enclosure moves the needle in a direction that is toward the second end of the implantable urine flow sensor and compressing the spring when the flowrate of urine is above the threshold. In some embodiments, the compression of the spring permits an amount of light from the light emitting unit to reach a receiver when the flowrate of urine is above the threshold. In some embodiments, the amount of light received by the receiver is a function of the flowrate of urine present within the flow path of the implantable urine flow sensor when the flowrate of urine is above the threshold. In some embodiments, the individual ureter is a donor ureter attached to a donor kidney proximal to the first portion of the stent and a bladder proximal to the second portion of the stent. In some embodiments, the electronics unit includes a printed circuit board coupled to an external portion of the enclosure, wherein the printed circuit board is flexible and is positioned longitudinally to a length of the implantable urine flow sensor. In some embodiments, the printed circuit board is coupled to the light emitting unit and a receiver on the external portion of the enclosure.

In some embodiments, the electronics unit further includes wireless transmission components. In some embodiments, the wireless transmission unit includes a piezoelectric transducer, an application specific integrated circuit (ASIC), and a flex antenna. In some embodiments, the piezoelectric transducer, the ASIC, and the flex antenna are coupled to a flexible circuit board. In some embodiments, the ASIC powers the implantable urine flow sensor from a power unit external to the ureter. In some embodiments, the electronics unit can transmit data about the implantable urine flow sensor to an external device. In some embodiments, the external device is a mobile device, a computer, an internet of things (loT) device and wherein the data is transmitted via Bluetooth Low Energy (BLE), Wi-Fi, or NFC. In some embodiments, the data about the implantable urine flow sensor is data about a rate of urine through the ureter to which the implantable urine flow sensor is positioned within.

In another aspect, example embodiments, devices, methods, and processes can include, or consist essentially of a method of using an implantable urine flow-sensor, including positioning the implantable urine flow-sensor of as described herein within a ureter coupled to a kidney; and monitoring, using the implantable urine flow sensor, a urine flowrate produced by the kidney. In some embodiments, the monitoring includes receiving urine flowrate data from a wireless transmission unit coupled to the implantable urine flowsensor. In some embodiments, the methods further include determining a treatment plan based on the received urine flowrate data. In some embodiments, the methods further include refraining from implementing the treatment plan based on the received urine flowrate data. In another aspect, the devices, methods, and processes disclosed herein include a method of manufacture of an implantable urine flow-sensor, including preparing a biocompatible material suitable for a stent; forming a stent structure from the biocompatible material; and selecting any implantable urine flow sensor device described herein.

In some embodiments, the method further includes forming the stent and the implantable urine flow-sensor as a single unit. In some embodiments, the stent structure is formed in two portions. In some embodiments, the method further includes coupling a first portion of the stent to a first end of the implantable urine flow sensor and coupling a second portion of the stent to a second end of the implantable urine flow sensor.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example of a flow-sensing device that includes a flow sensor coupled to a double- J stent.

FIG. 2 depicts a perspective view of the flow sensor of FIG. 1 positioned along the stent with the flow-path depicted.

FIG. 3 is a longitudinal cross-section view of the flow sensor of FIG. 1, with the flow sensor comprising an upstream flow-collection unit and a downstream flow vent both connected to an enclosure, a needle, a spring, and an electronics unit coupled to the outside of the enclosure.

FIG. 4 depicts a perspective view of an example of an electronics unit of the flow sensor of FIG. 1.

FIG. 5 depicts a perspective view of the needle of FIG. 3.

FIG. 6 depicts a longitudinal cross-section view of another example of a flow sensor coupled to a stent including an electronics unit and a needle.

FIG. 7 depicts another example of a flow-sensing device with a flow sensor coupled to a double-J stent.

FIG. 8 depicts a longitudinal cross-section of the flow sensor of FIG. 7 coupled to the stent and including a light emitting unit, a receiver, and a needle.

FIG. 9 depicts a perspective view of the needle of FIG. 8.

FIG. 10 depicts a perspective view of another example of a flow sensor coupled to a stent, and another exemplary electronics unit.

FIG. 11 depicts a flow diagram of an example of a method of using a flow-sensing device.

FIG. 12 depicts a flow diagram of an example of a method of manufacture of a flowsensing device. DETAILED DESCRIPTION

FIG. 1 depicts an example flow-sensing device 100 with a flow sensor 102 (e.g., an implantable flow sensor) coupled to a double-J stent 101. In some embodiments, the stent 101 can be manufactured separately from the flow sensor 102. In this configuration, the flow sensor 102 can be coupled to the stent 101 such that a lumen portion of the stent 101 traverses an interior portion of the flow sensor 102. In another configuration, the stent 101 can be coupled to the flow sensor 102 such that the stent 101 is in two pieces such that a first portion of the stent 101 is coupled to a first end of the flow sensor 102 and a second portion of the stent 101' is coupled to a second end of the flow sensor 102.

The stent 101 can be any type of stent that can address obstructions or strictures in the ureter, which is the tube that connects the kidney to the bladder. Ureteral stents can include a soft, hollow tube (e.g., a lumen) made of biocompatible materials such as silicone or polyurethane. In some examples, stents are inserted through the urethra, bladder, and into the ureter, allowing urine to flow freely from the kidney to the bladder while bypassing any obstructions. In other examples, stents are position in the ureter surgically allowing urine to flow freely from the kidney to the bladder while bypassing any obstructions. Non-limiting examples of ureteral stents include open-ended ureteral stents and closed-ended ureteral stents, dual-lumen ureteral stents, and coated ureteral stents.

Closed-ended stents are typically used for shorter-term applications or when the aim is to prevent retrograde urine flow. Non-limiting examples of closed-ended ureteral stents are straight closed-ended ureteral stent, curved closed-ended ureteral stent, or ureteral stent with a closed-end tip and pigtail or coil configuration (double-j stent).

Open-ended ureteral stents have a straight or slightly curved design and feature open tips at both ends. Unlike a double-j stent, which has a coiled or pigtail configuration, open- ended stents allow urine to flow freely from the kidney to the bladder without redirecting it towards the bladder wall. These stents are often used when temporary drainage is required, such as during certain surgical procedures or when monitoring the healing of the ureter. This type of stent can be used in kidney transplant surgery. Non-limiting examples of open-ended ureteral stents are straight open-ended ureteral stent, curved open-ended ureteral stent, or ureteral stent with multiple side holes.

In some example embodiments, the type of stent 101 coupled to the flow sensor 102 is a double-j stent. The double-j stent derives has a "J" shape. It has a pigtail or coil configuration at each end, which prevents the stent from migrating within the urinary system. The coiled ends of the double-j stent act as anchors, keeping the stent in its intended position within the urinary tract. This helps ensure proper drainage of urine from the kidney to the bladder while maintaining the alignment of the stent. One purpose of a double-j stent is to maintain a consistent flow of urine from the kidney to the bladder by bypassing any obstructions or strictures in the ureter. It is used in various urological conditions, including kidney stones, ureteral strictures, and kidney-transplant.

The flow-sensing device 100 can be of any suitable dimensions. In some embodiments, the flow-sensing device 100 can be about 20 cm to about 36 cm in length. For example, about 20 cm, about 22 cm, about 24 cm, about 26 cm, about 28 cm, about 30 cm, about 32 cm, about 34 cm, or about 36 cm. The flow-sensing device 100 can be configured to have a diameter that is appropriately sized for a ureter. In some embodiments, the flowsensing device 100 can have a diameter of less than about 4.6 mm. For example, about 2 mm to about 4.5 mm, about 2.5 to about 4.5 mm, about 3 mm to about 4.5 mm, about 3.5 mm to about 4.5 mm, about 4.0 mm to about 4.5 mm, about 2 mm to about 4 mm, about 2 mm to about 3.5 mm, about 2 mm to about 3 mm, or about 2 mm to about 2.5 mm. In some embodiments, the flow-sensing device 100 is less than about 4.2 mm in diameter. The improved urine detection flow-sensing device 100 described herein is sized such that it can be positioned in a single ureter and monitor the urine flow from an individual kidney. In some embodiments, the stent 101 coupled to the flow sensor 102 is a double-j stent that is positioned in the ureter during a kidney transplant. In this configuration, the flow-sensing device can monitor the urine flow and determine functionality of the donor kidney.

FIG. 2 depicts a perspective view of the flow sensor 102 of FIG. 1 positioned along the stent 101 with the flow-path as depicted. The flow path indicates the urine will flow into a lumen portion of a first portion of the stent 101 and the flow path of the urine will traverse through the flow sensor 102 to the second portion of the stent 101'. In the example embodiment shown by FIG. 2 the flow sensor 102 can be coupled to the stent 101 and comprise an upstream flow-collection unit 103 and a downstream flow vent 105 both connected to an enclosure 104, and an electronics unit 200 fixed to an exterior portion of the enclosure 104. The electronics unit 200 can be coupled to the flow sensor 102 and extend longitudinally on the flow sensor 102 and the stent 101' as indicated by 200'. In some example embodiments, the upstream flow-collection unit 103 can gather the urine expelled from the kidney and the downstream flow vent 105 can regulate pressure. For example, the upstream flow-collection unit 103 can gather the urine expelled from the kidney and direct it to the enclosure 104 for measurement. In some examples, the downstream flow vent 105 can be configured to regulate back-pressure and ensure smooth urine flow. For example, downstream flow vent 105 can act as an outlet for excess pressure that may build up within the upstream flow-collection unit 103 or enclosure 104. By allowing the controlled release of pressure, the downstream flow vent 105 can help maintain consistent flow conditions and can prevent any potential obstruction or disruption to the urine flow. The controlled release of pressure, the downstream flow vent 105 can also prevent a needle from dislodging and interrupting urine flow. The needle is discussed in more detail in connection with FIG. 3.

FIG. 3 is a longitudinal cross-section view of the flow sensor 102 of FIG. 1 with the flow sensor 102 comprising an upstream flow-collection unit 103 and a downstream flow vent 105 both connected to an enclosure 104, a needle 300, a spring 106, and an electronics unit 200 coupled to the outside of the enclosure 104. The electronics unit 200 can include portions that are flexible printed circuit boards 201a, 201b, and 201c (collectively referred to herein as 201). For example, the electronics unit 200 can include flexible printed circuit boards 201a and 201b that are coupled to the sides of the flow sensor 102 and extend longitudinally along the flow path as indicated by 201c. The electronics unit 200 further includes a light emitting unit 202 and a receiver 203. The electronics unit 200 is discussed in greater detail in connection with FIG. 4.

In some example embodiments, the needle 300 can include a stem portion 301 and a seat portion 302. When the spring 106 is not compressed, the geometry of the needle can substantially obstruct the flow of urine and light from the light emitting unit 202 being received by the receiver 203. The flow of urine along the flow path can cause a pressure differential in the annulus of the enclosure 104. The pressure differential can apply pressure to the surface of the stem portion 301 and the seat portion 302 to cause a spring 106 to compress. When the spring 106 is compressed, light from the light emitting unit 202 can be received by the receiver 203.

For example, as urine flows through the stent 101, a pressure differential is created between the entry of the flow sensor 102 (e.g., upstream flow-collection unit) and exit points (e.g., the downstream flow vent 105) of the flow sensor 102. This pressure differential is proportional to the flowrate of urine. The needle 300 is positioned within the flow sensor 102 and is free to move based on the pressure exerted by the urine flow. As urine flows through the tube, the pressure differential causes the needle 300 to deflect or move in response to the force applied by the urine flow. The extent of the needle's 300 displacement corresponds to the magnitude of the pressure differential, which in turn reflects the flowrate of urine. For example, as shown in FIG. 3, the needle 300 is positioned within the fluid pathway, and it is connected to a spring 106. The spring 106 provides resistance against compression and can be calibrated to respond to specific pressure levels.

In an example operation, urine flows through the flow path from a first portion of the stent 101 toward a second portion of the stent 101' and through the enclosure 104. As the pressure differential increases due to the urine flow, the force exerted on the needle 300 becomes stronger. When the pressure differential exceeds a threshold, the needle 300 can compress the spring 106 in a direction that is towards the second portion of the stent 101'. The needle 300 is designed to allow light to pass from the light emitting unit 202 to the receiver 203 when the spring 106 is compressed. In this configuration, the light emitting unit 202 (e.g., a light emitting diode (LED)) emits a beam of light towards the receiver 203. In contrast, as the spring remains uncompressed when the pressure differential has not exceeded the threshold, the needle 300 blocks the light beam from the light emitting unit 202 from reaching the receiver 203. The movement of the needle 300, triggered by the compression of the spring 106, determines whether the light beam from the light emitting unit 202 reaches the receiver 203 or not. When the urine flowrate generates enough pressure to compress the spring 106 and move the needle 300, the light beam from the light emitting unit 202 is allowed to pass through to the receiver 203, indicating the presence of fluid flow. By observing the light reception at the receiver 203, changes in the intensity or absence of the light beam from the light emitting unit 202 can be detected and used to infer the urine flowrate. The behavior of the needle 300 and spring 106 mechanism provides a visual or electrical signal that can be further processed or displayed to quantify and monitor the urine flowrate. In this configuration, because the flow sensor 102 is sized to be within a ureter, real-time information can be obtained about an individual kidney.

FIG. 4 depicts a perspective view of an exemplary electronics unit 200 of the flow sensor 102 of FIG. 1. In some example embodiments, the electronics unit 200 terminates within the ureter. For example, additional wires may penetrate through the subject’s tissue to connect the electronics unit 200 with an external power-source and/or an external data- acqui sition unit for powering the device and processing the data outputted from the receiver 203. The example electronics unit 200 includes a flexible printed circuit board 201, light emitting unit 202, and receiver 203.

The flexible printed circuit board 201 can be a thin, lightweight, and highly flexible electronic circuit made of biocompatible materials. It is designed to be safe and compatible with the human body, allowing it to be implanted or placed internally. For example, the flexible printed circuit board 201 can include circuitry that is created using conductive traces and components, such as resistors, capacitors, and integrated circuits. These components are mounted on a flexible substrate, which can be made of biocompatible materials like silicone or polyimide. The flexibility of the substrate enables the flexible printed circuit board 201 to conform to the contours of the body, minimizing discomfort and tissue irritation. To protect the circuitry and ensure biocompatibility, the flexible printed circuit board 201 can be encapsulated or covered with biocompatible coatings or materials. These coatings can provide insulation and protection against bodily fluids, preventing corrosion and adverse reactions within the body. In some embodiments, the flexible printed circuit board 201 may also include connectors or interfaces to facilitate communication with external devices, enabling data transmission or power supply.

The flexible printed circuit board 201 can be communicatively coupled to the light emitting unit 202. In some embodiments, the light emitting unit 202 is a small and compact LED. The specific type of LED used would depend on the desired wavelength or color of light required for detection and the sensitivity of the receiver. Non-limiting examples of LEDs include visible light LEDs (e.g., red, green, or blue) or infrared (IR) LEDs. The LED's wavelength range is selected to be compatible with biological tissue and optimization of detection. In some example embodiments, the receiver 203 is a photodetector designed to detect the light emitted by the light emitting unit 202 (e.g., LED). Non-limiting examples of a photodetector types include photodiodes or phototransistors. In some examples, the receiver 203 is compact in size to facilitate integration into the flow sensor 102 within a ureter of a subject.

FIG. 5 depicts a perspective view of the needle 300 of FIG. 3. The needle 300 includes a stem portion 301, with a surface 303, and a seat portion 302. A needle 300 can be of any suitable shape. The flow of urine along the flow path can cause a pressure differential on the surface 303 of the stem portion 301 and the seat portion 302 to apply pressure to cause a spring (e.g., spring) 106) to compress. In some embodiments, a needle 300 can include a surface 303 with sufficient surface area. For example, when the surface area of the surface 303 of the needle 300 is larger, it can result in a larger contact area in which to contact urine. As the urine flows past the needle 300, more urine can come into contact with the needle 300 surface 303. This increased interaction between the urine and the needle 300 surface can lead to a higher differential pressure. In some embodiments, less surface area may be beneficial to decrease the differential pressure within the flow sensor.

FIG. 6 depicts a longitudinal cross-section view of another example flow sensor 402 (e g., an implantable flow sensor) coupled to a stent 401 (the first portion identified as 401 and the second portion identified as 401') including an electronics unit and a needle 400. The stent 401 can be any of the stents described herein. In the example embodiment shown by FIG. 6 the needle 400 has a pointed shape. The surface area of the needle 400 can affect sensitivity of the flow sensor 402, in some cases measurement accuracy can be adjusted. For example, a larger surface area (e.g., needle 300) can provide enhanced sensitivity to detect even small changes in flowrate, while a smaller surface area (e.g., needle 400) may be suitable for measuring higher urine flowrates with better accuracy.

In an example operation, urine enters the flow-path, the annulus region created between the needle 400 and the enclosure 404 (e.g., enclosure 104) creates a change in pressure across the flow sensor 402. This pressure differential is above a threshold, the needle 400 compresses the spring 406 (e.g., spring 106). Since the change in pressure across the annulus is a function of the urine flowrate, the compression of the spring 406 is also a function of the flowrate.

When the flow sensor 402 is powered and flow is present through the flow sensor 402 the spring 406 is compressed by the needle 400, resulting in more light from the light emitting unit 409 (e.g., any of the light emitting units described herein) being exposed to the receiver 403. This causes a change in current, which is converted into a voltage outputted from the receiver 403 (e.g., any of the receivers described herein). This change in voltage directly corresponds to the urine flowrate through the stent 401 which allows the ability to measure a urine flowrate within a single ureter. In this configuration, the light emitting unit 409 (e.g., a LED) emits a beam of light towards the receiver 403. In contrast, as the spring 406 remains uncompressed when the pressure differential has not exceeded the threshold, the needle 400 blocks the light beam from the light emitting unit 409 from reaching the receiver 403.

FIG. 7 depicts an example flow-sensing device 1000 with a flow sensor 1102 (e.g., an implantable flow sensor) coupled to a double-J stent 1101. In some example embodiments, the flow sensor 1102 is coupled to the stent 1101 (e.g., any of the stents described herein). For example, the stent 1101 can be manufactured separately from the flow sensor 1102. In this configuration, the flow sensor 1102 can be coupled to the stent 1101 such that a lumen portion of the stent 1101 traverses an interior portion of the flow sensor 1102. In another configuration, the stent 1101 can be coupled to the flow sensor 1102 such that the stent 1101 is in two pieces such that a first portion of the stent 1101 is coupled to a first end of the flow sensor 1102 and a second portion of the stent 1101' is coupled to a second end of the flow sensor 1102.

The flow-sensing device 1000 can be of any suitable dimensions. In some embodiments, the flow-sensing device 1000 can be about 20 cm to about 36 cm in length. For example, about 20 cm, about 22 cm, about 24 cm, about 26 cm, about 28 cm, about 30 cm, about 32 cm, about 34 cm, or about 36 cm. The flow-sensing device 1000 can be configured to have a diameter that is appropriately sized for a ureter. In some embodiments, the flow-sensing device 1000 can have a diameter of less than about 4.6 mm. For example, about 2 mm to about 4.5 mm, about 2.5 to about 4.5 mm, about 3 mm to about 4.5 mm, about 3.5 mm to about 4.5 mm, about 4.0 mm to about 4.5 mm, about 2 mm to about 4 mm, about 2 mm to about 3.5 mm, about 2 mm to about 3 mm, or about 2 mm to about 2.5 mm. In some embodiments, the flow-sensing device 1000 is less than about 4.2 mm in diameter. The improved urine detection flow-sensing device 1000 described herein is sized such that it can be positioned in a single ureter and monitor the urine flow from an individual kidney. In some embodiments, the stent 1101 coupled to the flow sensor 1102 is a double-j stent that is positioned in the ureter during a kidney transplant. In this configuration, the flow-sensing device can monitor the urine flow and determine functionality of the donor kidney.

FIG. 8 depicts a longitudinal cross-section of the flow sensor 1102 of FIG. 7 coupled to the stent 1101 (the first portion identified as 1101 and the second portion identified as 1101') and including a light emitting unit, a receiver, and a needle 1300. The stent 1101 can be any of the stents described herein. In the example embodiment shown by FIG. 8 the needle 1300 has an irregular shape. As mentioned herein, the surface area of the needle can affect sensitivity of the flow sensor 1102, in some cases measurement accuracy can be adjusted. For example, a larger surface area (e.g., needle 300) can provide enhanced sensitivity to detect even small changes in flowrate, while a smaller surface area (e.g., needle 400) may be suitable for measuring higher urine flowrates with better accuracy.

In an example operation, urine enters the flow-path, the annulus region created between the needle 1300 and the enclosure 1104 (e g., enclosure 104) creates a change in pressure across the flow sensor 1102. Due to the irregular shape of needle 1300, the urine flow can exert pressure on multiple surfaces. For example, the pressure is created by the urine flow exerting pressure on the stem portion 1320 and the seat portion 1322. This pressure differential causes the needle 1300 to compress the spring 1106 (e.g., spring 106) when the pressure differential exceeds a threshold. Since the change in pressure is a function of the urine flowrate, the compression of the spring 1106 is therefore also a function of the flowrate. In this configuration, the light emitting unit 1202 (e.g., a light emitting diode (LED)) emits a beam of light towards the receiver 1203. In contrast, as the spring 1106 remains uncompressed when the pressure differential has not exceeded the threshold, the needle 1300 blocks the light beam from the light emitting unit 1202 from reaching the receiver 1203.

When the flow sensor 1102 is powered and flow is present through the flow sensor 1102 the spring 1106 is compressed by the needle 1300, resulting in more light from the light emitting unit 1202 (e.g., any of the light emitting units described herein) being exposed to the receiver 1103. This causes a change in current, which is converted into a voltage outputted from the receiver 403 (e.g., any of the receivers described herein). This change in voltage directly corresponds to the urine flowrate through the stent 1101 which allows the ability to measure a urine flowrate within a single ureter.

FIG. 9 depicts a perspective view of another exemplary needle 1300. The needle 1300 has an irregular shape. As mentioned herein, the surface area of the needle can affect sensitivity of the flow sensor 1102, in some cases measurement accuracy can be adjusted. For example, a larger surface area (e.g., needle 300) can provide enhanced sensitivity to detect even small changes in flowrate, while a smaller surface area (e.g., needle 400) may be suitable for measuring higher urine flowrates with better accuracy. In an example operation, urine enters the flow-path, the annulus region created between the needle 1300 and the enclosure 1104 (e.g., enclosure 104) creates a change in pressure across the flow sensor 1102. Due to the irregular shape of needle 1300, the urine flow can exert pressure on multiple surfaces. For example, the urine flow can exert a pressure on a first surface 1326 of the stem portion 1320 and a second surface 1328 of the seat portion 1322. The first surface 1326 and the second surface 1328 are connected via stem 1324. The irregular shape (e.g., with the stem portion 1320 having the open areas that allow passage of urine to the second surface 1328) can allow urine flow to contact a first surface 1326 and a second surface 1328. In some cases, the irregular shape that allows for the dual surface contact can increase the pressure differential (because of the additive nature of the pressures on the first surface 1326 plus on the second surface 1328) while keeping a compact design. In some cases, a compact design may be beneficial to fit other components (e.g., circuitry) onto the flow sensor.

FIG. 10 depicts a perspective illustration of another example flow sensor 2000 (e.g., an implantable flow sensor) coupled to a stent 2101 (e.g., a first portion identified as 2101 and a second portion identified as 2101'), and another exemplary electronics unit 2500. In some example embodiments, the electronics unit 2500 may also comprise components necessary for wireless transmission of power and data. For example, the electronics package can include a piezoelectric transducer to convert mechanical vibrations or pressure (e g., pressure differential caused by urine flow) into electrical signals. For example, in the flow sensor 2000, a piezoelectric transducer can be utilized to store energy differential pressure changes. In this configuration, a piezoelectric transducer can convert the mechanical energy into electrical energy to power the circuitry and wireless transmission components of the electronic unit 2500.

In some example embodiments, the electronics unit 2500 includes an Application- Specific Integrated Circuit (ASIC) to control and process the signals received from the receiver 203 and light emitting unit 202. In some configurations, it may include signal conditioning, amplification, analog-to-digital conversion (ADC), and digital signal processing (DSP) functions. The ASIC can also integrate communication protocols for wireless transmission, such as Bluetooth or Wi-Fi, enabling data transfer to external devices.

In some example embodiments, the electronics unit 2500 includes a flex antenna that can be conformably integrated into the electronics unit 200. In some examples, the flex antenna can be configured to transmit and receive electromagnetic signals wirelessly. It can be designed to operate at specific frequencies suitable for the intended wireless communication standard, ensuring reliable and robust wireless connectivity. The flex antenna allows for efficient wireless power and data transmission between the implant and external devices.

In some example embodiments, the electronics unit 2500 includes a power management circuit for regulating and distributing the power received from the piezoelectric transducer or any other power source (e.g., a battery). A power management circuit ensures efficient power utilization, voltage regulation, and may include components such as voltage regulators, energy storage elements (e.g., capacitors or batteries), and power conditioning circuits.

In some example embodiments, the electronics unit 2500 includes a dedicated communication module to facilitate wireless data transmission between the flow sensor 102 and external devices (e.g., mobile devices, computers, loT devices, etc.). A communication module can include a wireless transceiver that supports the desired communication standard (e.g., Bluetooth Low Energy, Wi-Fi, or NFC) and associated circuitry for encoding, decoding, and processing data.

In some example embodiments, the electronics unit 2500 includes a microcontroller or digital signal processor (DSP) to function as the central processing unit (CPU) for the flow sensor 102. A microcontroller or DSP can control the operation of various components, handle data processing tasks, manage power consumption, and execute algorithms specific to the flow sensor’s 102 functionality.

In some example embodiments, the electronics unit 2500 includes one or more memory components to store data, firmware, calibration parameters, or subject-specific information. These memory elements can be non-volatile, such as flash memory or Electrically Erasable Programmable Read-Only Memory (EEPROM), to retain data even when power is disconnected.

In some example embodiments, the electronics unit 2500 includes additional sensors to measure other physiological parameters or environmental variables. In some examples, one or more sensors include temperature sensors, pressure sensors, or other relevant sensors to provide additional data for comprehensive monitoring or control. Methods of using a flow sensor (e.g., any flow sensor described herein) include positioning the flow sensor within a ureter during a surgical procedure. The flow sensors described herein include improvements to prior urine monitoring solutions. For example, the flow sensors described herein are sized to fit within an individual ureter and can monitor the urine production of an individual kidney. This can be particularly advantageous to monitor the urine production of a donor kidney. The improved flow sensor as described herein can provide data about the flowrate of urine from an individual kidney (e.g., a donor kidney) to an individual (e.g., a patient or healthcare provider) wirelessly. In this way, decisions regarding treatment or intervention can be made with minimal invasive techniques. This can allow a subject to recover at home and decrease visits to a physician.

FIG. 11 depicts a flow diagram of a method 600 of using a flow-sensing device (e.g., any flow-sensing device described herein). At 602, method 600 includes positioning a flowsensing device (e.g., any flow-sensing device described herein) within a donor ureter coupled to a donor kidney. In some embodiments, the flow device is coupled to a stent as a single piece. In some example embodiments, the flow device is separate from the stent and they are coupled together prior to placement with the donor ureter.

At 604, method 600 includes monitoring a urine flowrate produced by the donor kidney. In some embodiments, monitoring can include receiving urine flowrate data from a wireless transmission unit coupled to the flow-sensing device. For example, a physician can receive the urine flowrate data on a computer or a mobile device. In some embodiments, receiving the flowrate data can include determining a treatment plan based on the received urine flowrate data. For example, the treatment plan can include an initiation of a medication. In other examples, the treatment can include a surgical procedure (e.g., to replace, remove, or reposition the flow-sensing device). In some embodiments, receiving the flowrate data can include refraining from implementing a treatment plan based on the received urine flowrate data. For example, the flowrate data can indicate that the donor kidney is functioning well and no treatment intervention is needed.

Methods of manufacturing a flow-sensing device can include manufacturing a stent (e.g., any of the stents described herein) integrated with a flow sensor (e.g., any of the flow sensors described herein). In one embodiment, the stent and flow sensor are formed together as a single unit, which can provide sufficient alignment and seamless integration. In a second embodiment, the stent is manufactured in two pieces, with each piece designed to couple a respective end of the flow sensor. Both embodiments provide efficient and reliable integration of the stent and flow sensor capabilities.

FIG. 12 depicts a flow diagram of a method 700 of manufacture of a flow-sensing device (e g., any flow-sensing device described herein). At 702, method 700 includes preparing a biocompatible material suitable for a stent. For example, a biocompatible material suitable for stent fabrication can include stainless steel or a biodegradable polymer. At 704, method 700 can include forming the stent structure from the biocompatable material. For example, stent manufacturing techniques, such as laser cutting or chemical etching, to shape and form the stent structure according to dimensions sized to fit within an individual ureter. At 706, the method 700 can include selecting a flow device (e.g., any of the flow devices described herein). For example, the flow device can be sized such that it can integrated with the stent and sized to be positioned within an individual ureter. In some embodiments, the stent and the flow-sensing device are manufactured as a single unit. In some embodiments, the stent structure is manufactured in two portions. In some embodiments, the method of manufacture can further comprise coupling a first portion of the stent to a first end of the flow device and coupling a second portion of the stent to a second end of the flow device.

OTHER EMBODIMENTS

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. An implantable urine flow sensor, comprising: a first end coupled to a first portion of a uretic stent; and a second end coupled to a second portion of the uretic stent, wherein the implantable urine flow sensor is sized to fit within an individual ureter.

2. The implantable urine flow sensor of claim 1, wherein the stent is one of an open-ended ureteral stent or a closed-ended ureteral stent.

3. The implantable urine flow sensor of any one of claims 1-2, wherein the stent is a double-j stent.

4. The implantable urine flow sensor of any one of claims 1-3, wherein a diameter of the implantable urine flow sensor is less than about 4.2 mm.

5. The implantable urine flow sensor of any one of claims 1-4, further comprising: an upstream flow-collection unit located at the first end; a downstream flow vent located at the second end; an enclosure located between the upstream flow-collection unit and the downstream flow vent, wherein a urine flow path traverses a lumen of the stent from the first portion, through the enclosure, to the second portion; a needle positioned within the enclosure; and a spring positioned within the enclosure proximal to the second end.

6. The implantable urine flow sensor of claim 5, wherein the upstream flow-collection unit gathers the urine expelled from a kidney via the ureter and directs it to the enclosure for measurement.

7. The implantable urine flow sensor of claim 5 or claim 6, wherein the downstream flow vent is configured to maintain a consistent flow of urine and regulate back pressure.

8. The implantable urine flow sensor of any one of claims 5-7 wherein the enclosure is configured to contain the urine collected from the ureter for measurement with the needle and the spring.

9. The implantable urine flow sensor of claim 5, wherein the needle is positioned in the enclosure within the flow path and substantially restricting a flow of urine from the first portion of the stent to the second portion of the stent.

10. The implantable urine flow sensor of any one of claims 5-9, wherein the needle has geometry that includes a pointed shape, a blunt shape, or an irregular shape.

11. The implantable urine flow sensor of any one of claims 5-10, further comprising an electronics unit coupled to the enclosure.

12. The implantable urine flow sensor of claim 11, wherein the electronics unit comprises: a light emitting unit positioned within the enclosure; and a receiver positioned within the enclosure across from the light emitting unit.

13. The implantable urine flow sensor of claim 12, wherein the light emitting unit is a light emitting diode.

14. The implantable urine flow sensor of any one of claims 9-13, wherein the needle is positioned in the enclosure within the flow path and substantially blocks light from the light emitting unit from reaching the receiver when a flowrate of urine is below a threshold.

15. The implantable urine flow sensor of claim 14, wherein a flow of urine through the enclosure moves the needle in a direction that is toward the second end of the implantable urine flow sensor and compressing the spring when the flowrate of urine is above the threshold.

16. The implantable urine flow sensor of claim 15, wherein the compression of the spring permits an amount of light from the light emitting unit to reach a receiver when the flowrate of urine is above the threshold.

17. The implantable urine flow sensor of claim 16, wherein the amount of light received by the receiver is a function of the flowrate of urine present within the flow path of the implantable urine flow sensor when the flowrate of urine is above the threshold.

18. The implantable urine flow sensor of any one of claims 1-17, wherein the individual ureter is a donor ureter attached to a donor kidney proximal to the first portion of the stent and a bladder proximal to the second portion of the stent.

19. The implantable urine flow sensor of any one of claims 12-18, wherein the electronics unit comprises a printed circuit board coupled to an external portion of the enclosure, wherein the printed circuit board is flexible and is positioned longitudinally to a length of the implantable urine flow sensor.

20. The implantable urine flow sensor of claim 19, wherein the printed circuit board is coupled to the light emitting unit and a receiver on the external portion of the enclosure.

21. The implantable urine flow sensor of any one of claims 12-18, wherein the electronics unit further comprises wireless transmission components.

22. The implantable urine flow sensor of any one of claim 21, wherein the wireless transmission unit comprises a piezoelectric transducer, an application specific integrated circuit (ASIC), and a flex antenna.

23. The implantable urine flow sensor of claim 22, wherein the piezoelectric transducer, the ASIC, and the flex antenna are coupled to a flexible circuit board.

24. The implantable urine flow sensor of claim 22 or claim 23, wherein the ASIC powers the implantable urine flow sensor from a power unit external to the ureter.

25. The implantable urine flow sensor of any one of claims 19-24, wherein the electronics unit can transmit data about the implantable urine flow sensor to an external device.

26. The implantable urine flow sensor of claim 25, wherein the external device is a mobile device, a computer, an internet of things (loT) device and wherein the data is transmitted via Bluetooth Low Energy (BLE), Wi-Fi, or NFC.

27. The implantable urine flow sensor of claim 25 or claim 26, wherein the data about the implantable urine flow sensor is data about a rate of urine through the ureter to which the implantable urine flow sensor is positioned within.

28. A method of using an implantable urine flow-sensor, comprising: positioning the implantable urine flow-sensor of any one of claims 1-27 within a ureter coupled to a kidney; and monitoring, using the implantable urine flow sensor, a urine flowrate produced by the kidney.

29. The method of claim 28, wherein the monitoring comprises receiving urine flowrate data from a wireless transmission unit coupled to the implantable urine flow-sensor.

30. The method of claim 29, further comprising determining a treatment plan based on the received urine flowrate data.

31. The method of claim 30, further comprising refraining from implementing the treatment plan based on the received urine flowrate data.

32. A method of manufacture of an implantable urine flow-sensor, comprising: preparing a biocompatible material suitable for a stent; forming a stent structure from the biocompatible material; and selecting the implantable urine flow sensor device of any one of claims 1-27.

33. The method of claim 32, further comprising forming the stent and the implantable urine flow-sensor as a single unit.

34. The method of claim 33, wherein the stent structure is formed in two portions.

35. The method of claim 34, further comprising coupling a first portion of the stent to a first end of the implantable urine flow sensor and coupling a second portion of the stent to a second end of the implantable urine flow sensor.