Urology catheter

Abstract

A device and system for measuring pressures applied to the urethra. The device comprises a catheter tube comprising a proximal end and a distal end; a balloon, located at the distal end of the catheter tube, wherein the balloon is configured to inflate to anchor the catheter tube in position when the device is in use; and one or more pressure sensors, distributed along the catheter tube, wherein the one or more pressure sensors are configured to measure external pressure applied to the catheter tube. The specification also provides for a computer implemented method receiving one or more pressure measurements from one or more pressure sensors and determining a location of a centre of pressure based on the one or more pressure measurements and the positions of the one or more pressure sensors.

Description

[0001] Urology Catheter

[0002] Field

[0003] This specification relates to a device 100, method and system for measuring pressures applied to the urethra.

[0004] Background

[0005] Stress Urinary Incontinence (SUI) is the most common form of incontinence in women and results typically from injury to pelvic floor during vaginal delivery. This trauma to the bladder outlet results in a closure pressure which can be overcome when intra-abdominal pressure is raised during activities such as coughing and straining, resulting in incontinence.

[0006] Surgery to treat SUI aims to increase the bladder outlet pressure by either bulking or supporting the urethra. The autologous facial sling procedure achieves this by using a ribbon of fascial tissue as a sling to support the urethra. Optimal sling tension is key to maximising treatment efficacy while minimising complications. If the sling is too loose, the urethral closure pressure is not adequate to prevent SUI. If the sling is too tight, the bladder must work hard to overcome the high urethral resistance to generate flow. This results in new-onset overactive bladder symptoms such as frequency, urgency, urge incontinence, incomplete bladder emptying and associated urinary tract infections.

[0007] Achieving the optimal tension during the autologous fascial sling procedure is technically challenging and heavily relies on the surgeon's subjective judgement. This reliance upon a surgeon's skill and experience means that there may be a variation between surgeons. In addition, this tacit knowledge is also difficult to transfer to trainees.

[0008] Summary

[0009] The present specification relates to a device for measuring pressures applied to the urethra. The device comprises a catheter tube comprising a proximal end and a distal end, and a balloon, located at the distal end of the catheter tube, wherein the balloon is configured to inflate to anchor the catheter tube in position when the device is in use. The device further comprises one or more pressure sensors, distributed along the catheter tube, wherein the one or more pressure sensors are configured to measure external pressure applied to the catheter tube. By measuring the external pressure applied to the catheter tube, the device can be used to determine the tension of an autologous fascial sling during an autologous fascial sling procedure.

[0010] In an embodiment, the one or more pressure sensors are distributed between the balloon and the centre of the catheter tube. In an embodiment, the one or more pressure sensors are positioned at regular intervals along the catheter tube, for example the one or more pressure sensors may be positioned at 1cm intervals. In an embodiment, the device may comprise six pressure sensors.

[0011] In an embodiment, the one or more pressure sensors are configured to take realtime pressure measurements.

[0012] In an embodiment, the balloon is configured to deflate such that the catheter tube can be removed when the device is not in use. The balloon may have a capacity of 5ml.

[0013] The specification also provides for a computer implemented method comprising receiving one or more pressure measurements from one or more pressure sensors, wherein the one or more pressure sensors are distributed along a catheter tube and are configured to measure external pressure applied to the catheter tube. The computer implemented method further comprises determining a location of a centre of pressure based on the one or more pressure measurements and the positions of the one or more pressure sensors.

[0014] In an embodiment, determining the location of the centre of pressure comprises calculating the mean of the positions of the one or more pressure sensors weighted by the one or more pressure measurements.

[0015] In an embodiment the positions of the one or more pressure sensors are measured from a distal end of the catheter tube.

[0016] In an embodiment, the method further comprises displaying the one or more pressure measurements and / or the location of the centre of pressure on a user interface. The one or more pressure measurements may be received in real time, and the location of the centre of pressure may be calculated in real time.

[0017] The specification further provides for a system for measuring pressures applied to the urethra. The system comprises a device, the device comprising a catheter tube comprising a proximal end and a distal end; a balloon, located at the distal end of the catheter tube, wherein the balloon is configured to inflate to anchor the catheter tube in position when the device is in use; and one or more pressure sensors, distributed along the catheter tube, wherein the one or more pressure sensors are configured to measure external pressure applied to the catheter tube. The system further comprises data processing apparatus in communication with the device and configured to receive one or more pressure measurements from the one or more pressure sensors, and determine a location of a centre of pressure based on the one or more pressure measurements and the positions of the one or more pressure sensors.

[0018] In an embodiment, the system further comprises a microcontroller configured to obtain one or more pressure measurements from each of the one or more pressure sensors and to transmit said one or more pressure measurements to the data processing apparatus.

[0019] The system may also comprise a user interface configured to display the one or more pressure measurements and / or the location of the centre of pressure in real time.

[0020] Brief description of the drawings

[0021] Figure 1 shows a device according to the present specification;

[0022] Figure 2 shows a close-up view of an inflated balloon according to the present specification;

[0023] Figure 3 shows a pressure sensor array according to the present specification;

[0024] Figure 4 shows the device of Figure 1 during use;

[0025] Figure 5 depicts a computer implemented method for measuring a location of the centre of pressure according to the present specification; Figure 6 shows a system according to the present specification;

[0026] Figure 7 shows an example screenshot of a user interface according to the present specification.

[0027] Detailed description

[0028] Figure 1 shows a device 100 according to the present specification. The device 100 comprises a catheter tube 101. In use, the catheter tube 101 is inserted through the urethra and into the bladder in order to drain the bladder. The catheter tube 101 may comprise any suitable urinary catheter and may be made of any suitable material. Example materials may include silicone, latex, or polyurethane.

[0029] The catheter tube 101 comprises a distal end 102 and a proximal end 103. In this specification, the distal end 102 is defined as the end of the catheter tube 101 that is closest to the bladder when the catheter is inserted into the urethra, and the proximal end 103 is the end of the catheter tube 101 which protrudes externally from the urethra.

[0030] A balloon 104 is located at the distal end 102 of the catheter tube 101. The balloon 104 is configured to inflate when the catheter is in position in the urethra. The balloon 104 inflates inside the bladder and acts as an anchor to hold the catheter tube 101 in position and prevent accidental removal. More specifically, in an embodiment the catheter tube 101 may comprise two channels. The first channel is configured to drain the bladder. The second channel is configured to supply water to the balloon 104. As the balloon 104 fills with water, it inflates. When the catheter is ready to be removed, the water is drained from the balloon 104 via the second channel. A valve is located at the proximal end 103 of the second channel to switch between supplying the balloon 104 with water and draining the balloon 104. In this way, the catheter tube 101 is held in position in the urethra in a repeatable manner. In the art, a catheter of this type is referred to as a Foley catheter or an indwelling urinary catheter.

[0031] A close up of the inflated balloon 104 is shown in Figure 2. The balloon 104 may be made of any suitable material. Suitable materials include silicone and latex. The balloon 104 may have a total volume of 5ml. Returning to Figure 1, the device 100 further comprises an array of one or more pressure sensors 105 distributed along the catheter tube 101.

[0032] The one or more pressure sensors 105 may be located in any suitable positions along the length of the catheter tube 101. In an embodiment, the one or more pressure sensors 105 may be positioned at regular intervals along the catheter tube 101. Alternatively, the one or more pressure sensors 105 may be positioned at irregular intervals. For example, the spacing between sensors may be reduced close to the anticipated location centre of pressure. In an embodiment, the pressure sensors may be distributed close to the distal end 102 of the catheter tube 101, such as between the balloon 104 and the centre of the catheter tube 101.

[0033] In an embodiment, the spacing between adjacent pressure sensors may be less than 2cm, such as less than 1cm, such as less than 0.5cm. In an embodiment, the device 100 may comprise multiple pressure sensors, such as more than two pressure sensors, such as more than five pressure sensors.

[0034] As an example embodiment, the device 100 may comprise six pressure sensors evenly distributed at 1cm intervals starting from the internal edge of the balloon 104 and working towards the centre of the catheter.

[0035] The one or more pressure sensors 105 may comprise any suitable pressure sensors. Suitable commercially available pressure sensors include the TE connectivity MS5840-02BA01. In some embodiments, the one or more pressure sensors 105 may be housed in an outer casing. Advantageously, the one or more pressure sensors 105 are positioned such that any external pressure is applied directly to the pressure sensor and not to the outer casing.

[0036] In one embodiment, shown in Figure 3, the one or more pressure sensors 105 are attached to a flexible printed circuit board (PCB) 301, and the device 100 is produced by fitting the PCB 301 to the catheter tube 101. In some embodiments, the device 100 may be produced by retrofitting the flexible PCB 301 comprising the one or more pressure sensors 105 into a standard Foley catheter. By producing the device 100 using a standard Foley catheter, the device 100 can be readily adopted into standard practice, because the clinical technique for inserting the catheter is unchanged. Figure 4 shows the device 100 in use during the autologous fascial sling procedure. Although Figure 4 depicts a female anatomy, it will be appreciated that the device 100 is also suitable for use during male SUI surgery, such as male sling surgery. Furthermore, the device 100 may be used in other types of urinary surgery, including any procedure with a mechanism of action which potentially increases urethral resistance.

[0037] The device 100 is inserted into the urethra, and the balloon 104 is inflated within the bladder to anchor the device 100 in position. The device 100 is positioned such that the one or more pressure sensors 105 are able to measure the pressure applied to the urethra by the autologous fascial sling.

[0038] The tension of the autologous fascial sling is indirectly measured via the pressure applied to the urethra. As the tension of the sling increases a greater force will be applied to the urethra resulting in an increase in the pressure applied to the urethra. A decrease in tension would result in a decrease in pressure.

[0039] As pressure applied to the urethra is transmitted to the device 100, the one or more pressure sensors 105 record the pressure applied. The inventors have found that there is a linear relationship between the tension of the sling and the pressure measured by the device 100. Therefore, by measuring the pressure applied to the urethra, the device 100 can be used to determine the tension of the autologous fascial sling. In this way, the device 100 may be used to quantify the optimum sling tension, which until now has been measured subjectively by surgeons.

[0040] In some embodiments, the one or more pressure sensors 105 are configured to take real time pressure measurements. In this way, a surgeon can adjust the tension of the autologous fascial sling in real time during surgery, guided by the pressure measurements taken by the device 100.

[0041] Furthermore, because the location of the one or more pressure sensors 105 is known and is fixed relative to the balloon 104, the device 100 can be used to calculate a location of the centre of pressure, and, by analogy, the location of the autologous fascial sling. Figure 5 depicts a computer implemented method for measuring a location of the centre of pressure. The method may be performed by a data processing apparatus, such as the data processing apparatus 601 described below.

[0042] At step 501, the method comprises receiving one or more pressure measurements from one or more pressure sensors. In an embodiment, the one or more pressure sensors are the one or more pressure sensors 105 of the device 100.

[0043] At step 502, a location of a centre of pressure is determined based on the one or more pressure measurements and the positions of the one or more pressure sensors. In some embodiments, determining the location of the centre of pressure comprises calculating the mean of the positions of the one or more pressure sensors weighted by the one or more pressure measurements. Other methods of calculating the centre of pressure may also be used.

[0044] The resolution of the location of the centre of pressure may be improved by reducing the spacing between the one or more pressure sensors 105. Additionally or alternatively, increasing the number of pressure sensors may also improve the resolution of the location of the centre of pressure.

[0045] As noted above, the one or more pressure sensors 105 may be configured to take real time pressure measurements, and the location of the centre of pressure may be calculated in real time. In some embodiments, the method 500 may additionally comprise displaying 503 the pressure measurements and / or the location of the centre of pressure on a user interface. As discussed above, by viewing the real time pressure measurements, the surgeon can adjust the tension of the autologous fascial sling in real time during surgery. In addition, by viewing the location of the centre of pressure in real time, the surgeon can adjust the position of the autologous fascial sling during surgery based on the location of the centre of pressure. In other words, the surgeon can respond in real-time to feedback from the device 100 presented via the user interface. In this way, the accuracy of both the tension and position of the autologous fascial sling can be improved, improving the efficacy of the surgery and reducing the risk of complications for the patient.

[0046] Figure 6 shows a system 600 according to the present specification. The system 600 comprises the device 100 and data processing apparatus 601, configured to perform the steps of the method 500. The device 100 is in communication with the data processing apparatus 601. In some embodiments, the system further comprises a microcontroller 602 configured to obtain one or more pressure measurements from each of the one or more pressure sensors 105 and to transmit said one or more pressure measurements to the data processing apparatus. For example, the microcontroller 602 may be attached to the device 100 and configured to transmit the one or more pressure measurements to the data processing apparatus 601 via a Bluetooth connection. Alternatively, the device 100 may be connected directly to the data processing apparatus 601, for example via a wired connection.

[0047] In some embodiments the system may also comprise a user interface 603. The user interface 603 may be configured to display the one or more pressure measurements and / or the location of the centre of pressure in real time. Figure 7 shows an example screenshot of the user interface 603. In the example of Figure 7, the user interface 603 displays the pressure measured by each of the one or more pressure sensors as a continuous graph, with each pressure sensor identified by its distance from the balloon. Furthermore, the user interface displays a representation of the device 100 (shown on the right-hand side of Figure 7). Colour mapping on the representation of the device provides a visual indication of the pressure applied to different parts of the catheter tube, with a stronger colour indicating a higher pressure. For example, in Figure 7 the highest pressure is applied at the pressure sensor 3cm from the balloon. In this way, both the strength of the pressure applied and the location of the centre of pressure can be visualised in real-time whilst the surgery is being performed.

[0048] In some embodiments the data processing apparatus 601 can record the pressure measurements and the location of the centre of pressure for future reference and patient records. Furthermore, the data processing apparatus may be configured to record timestamps to mark events during the surgery, for example the start of tensioning of the sling.

[0049] Various modifications and variations will be apparent to those skilled in the art which fall within the scope of the following claims.

Claims

Claims1. A device for measuring pressures applied to the urethra, the device comprising: a catheter tube comprising a proximal end and a distal end; a balloon, located at the distal end of the catheter tube, wherein the balloon is configured to inflate to anchor the catheter tube in position when the device is in use; and one or more pressure sensors, distributed along the catheter tube, wherein the one or more pressure sensors are configured to measure external pressure applied to the catheter tube.

2. The device of claim 1, wherein the one or more pressure sensors are distributed between the balloon and the centre of the catheter tube.

3. The device of any preceding claim, wherein the one or more pressure sensors are positioned at regular intervals along the catheter tube.

4. The device of claim 3, wherein the one or more pressure sensors are positioned at 1cm intervals.

5. The device of any preceding claim, comprising six pressure sensors.

6. The device of any preceding claim, wherein the one or more pressure sensors are configured to take real-time pressure measurements.

7. The device of any preceding claim, wherein the balloon is configured to deflate such that the catheter tube can be removed when the device is not in use.

8. The device of any preceding claim, wherein the balloon has a capacity of5ml.

9. A computer implemented method comprising: receiving one or more pressure measurements from one or more pressure sensors, wherein the one or more pressure sensors are distributed along a catheter tube and are configured to measure external pressure applied to the catheter tube;determining a location of a centre of pressure based on the one or more pressure measurements and the positions of the one or more pressure sensors.

10. The method of claim 9, wherein determining the location of the centre of pressure comprises calculating the mean of the positions of the one or more pressure sensors weighted by the one or more pressure measurements.

11. The method of claim 9 or 10, wherein the positions of the one or more pressure sensors are measured from a distal end of the catheter tube.

12. The method of any of claims 9 to 11, further comprising displaying the one or more pressure measurements and / or the location of the centre of pressure on a user interface.

13. The method of any of claims 9 to 12, wherein the one or more pressure measurements are received in real time.

14. The method of any of claims 9 to 13, wherein the location of the centre of pressure is calculated in real time.

15. A system for measuring pressures applied to the urethra comprising: a device comprising: a catheter tube comprising a proximal end and a distal end; a balloon, located at the distal end of the catheter tube, wherein the balloon is configured to inflate to anchor the catheter tube in position when the device is in use; and one or more pressure sensors, distributed along the catheter tube, wherein the one or more pressure sensors are configured to measure external pressure applied to the catheter tube; and data processing apparatus in communication with the device, the data processing apparatus configure to: receive one or more pressure measurements from the one or more pressure sensors, and determine a location of a centre of pressure based on the one or more pressure measurements and the positions of the one or more pressure sensors.

16. The system of claim 15, further comprising a microcontroller configured to obtain one or more pressure measurements from each of the one or more pressure sensors and to transmit said one or more pressure measurements to the data processing apparatus.

17. The system of claim 15 or claim 16, further comprising a user interface configured to display the one or more pressure measurements and / or the location of the centre of pressure in real time.

Images