Multi-tube sensor for sensing urinary sphincter and urethral pressure
The disclosure describes a multi-tube pressure sensor to measure the pressure at two sites that may be used in a therapeutic incontinence control system. The system senses urinary sphincter pressure and urethral pressure and sends the information to a stimulator that is capable of stimulation therapy to control sphincter contractility, thus reducing unwanted urinary incontinence. Measuring sphincter pressure is accomplished through the use of a tube placed through the sphincter and urethral pressure is measured by a second tube placed within the urethra, both tubes may be attached to a single module implanted within the bladder. Pressure within the tube generates an electrical signal that is sent wirelessly to an implanted stimulator connected to a lead positioned near pelvic floor nerves. An external device may be used to wirelessly send information to the implanted stimulator and inhibit stimulation in order for the patient to empty the bladder. Additionally, the pressure information and stimulation information may be recorded and reviewed for continued patient monitoring.
1. An implantable pressure sensor comprising:
a sensor housing;
a first flexible tube extending from the housing;
a second flexible tube extending from the housing; and
a sensing device that senses a fluid pressure within the first flexible tube indicative of a urinary sphincter pressure level outside of the first flexible tube when the first flexible tube is positioned adjacent a urinary sphincter of a patient, and senses a fluid pressure within the second flexible tube indicative of a urethral pressure level outside of the second flexible tube when the second flexible tube is positioned within a urethra of the patient,
wherein each of the first flexible tube and the second flexible tube includes a closed distal end and an open proximal end in communication with the sensing device, and
wherein a proximal portion of the second flexible tube is disposed within the first flexible tube, and a distal portion of the second flexible tube extends beyond a distal portion of the first flexible tube such that the distal portion of the second flexible tube is positioned within the urethra when the first flexible tube is positioned adjacent to the urinary sphincter.
2. The sensor of claim 1 , wherein the second flexible tube is longer than the first flexible tube.
3. The sensor of claim 1 , wherein the second flexible tube is disposed substantially concentrically within the first flexible tube.
4. The sensor of claim 1 , further comprising a substantially rigid interface tube that separates an outer surface of the second flexible tube from an inner surface of the first flexible tube.
5. The sensor of claim 4 , wherein the first flexible tube comprises a material, the second flexible tube comprise the same material, and the rigid interface tube comprises the same material with a greater density than the first flexible tube and the second flexible tube.
6. The sensor of claim 4 , wherein the rigid interface tube is configured to substantially prevent pressure exerted on the first flexible tube from affecting the pressure within the second flexible tube.
7. The sensor of claim 1 , wherein the sensing device includes a first sensing element that senses the fluid pressure within the first flexible tube, and a second sensing element that senses the fluid pressure within the second flexible tube.
8. The sensor of claim 1 , wherein the sensing device includes a strain gauge sensor that generates an electrical signal indicative of fluid pressure within at least one of the first and second flexible tubes.
9. The sensor of claim 1 , further comprising a wireless telemetry interface that transmits information based on the sensed fluid pressure.
10. The sensor of claim 1 , wherein the sensor housing includes a fixation mechanism to mount the sensor housing within a bladder of a patient.
11. The sensor of claim 1 , further comprising a memory that stores information based on the sensed pressures.
12. The sensor of claim 1 , wherein the first flexible tube has an outer diameter sized less than an inner diameter of the urethra.
13. The sensor of claim 1 , wherein the first flexible tube has a substantially circular cross-section.
14. The sensor of claim 1 , wherein the distal portion of the second flexible tube extends approximately 1 to 3 centimeters beyond the distal portion of the first flexible tube.
15. A system comprising:
an implantable pressure sensor comprising:
a sensor housing,
a first flexible tube extending from the housing,
a second flexible tube extending from the housing, and
a sensing device that senses a fluid pressure within the first flexible tube indicative of a urinary sphincter pressure level outside of the first flexible tube when the first flexible tube is positioned adjacent a urinary sphincter of a patient, and senses a fluid pressure within the second flexible tube outside of the second flexible tube indicative of a urethral pressure level when the second flexible tube is positioned within a urethra of the patient,
wherein each of the first flexible tube and the second flexible tube includes a closed distal end and an open proximal end in communication with the sensing device, and
wherein a proximal portion of the second flexible tube is disposed within the first flexible tube, and a distal portion of the second flexible tube extends beyond a distal portion of the first flexible tube such that the distal portion of the second flexible tube is positioned within the urethra when the first flexible tube is positioned adjacent to the urinary sphincter; and
an implantable stimulator that delivers electrical stimulation to the patient based on the sensed pressures.
16. The system of claim 15 , wherein the second flexible tube is longer than the first flexible tube.
17. The system of claim 15 , wherein the second flexible tube is disposed substantially concentrically within the first flexible tube.
18. The system of claim 15 , wherein the sensing device includes a first sensing element that senses the fluid pressure within the first flexible tube, and a second sensing element that senses the fluid pressure within the second flexible tube.
19. The system of claim 15 , further comprising a wireless telemetry interface that transmits information based on the sensed fluid pressure to the implantable stimulator.
20. The system of claim 19 wherein the implantable stimulator adjusts one or more stimulation parameters of the electrical stimulation based on the transmitted information.
21. The system of claim 19 , further comprising an external programmer to adjust stimulation parameters associated with the electrical stimulation delivered by the implantable stimulator, wherein the telemetry interface transmits the information to the external programmer.
22. The system of claim 19 , wherein the implantable stimulator is configured to deliver electrical stimulation to the patient to alleviate urinary incontinence.
23. A method comprising:
sensing via a sensing device a first pressure level exerted by a urinary sphincter within a patient based on a pressure of fluid within a first flexible tube placed proximate to the urinary sphincter; and
sensing via the sensing device a second pressure level exerted within a urethra of the patient based on a pressure of fluid within a second flexible tube placed within the urethra below the urinary sphincter,
wherein each of the first flexible tube and the second flexible tube includes a closed distal end and an open proximal end in communication with the sensing device, and
wherein a proximal portion of the second flexible tube is disposed within the first flexible tube, and a distal portion of the second flexible tube extends beyond a distal portion of the first flexible tube such that the distal portion of the second flexible tube is positioned within the urethra when the first flexible tube is positioned adjacent to the urinary sphincter.
24. The method of claim 23 , further comprising delivering electrical stimulation to the patient based on the sensed pressure levels.
25. The method of claim 24 , wherein the electrical stimulation is configured to alleviate urinary incontinence.
26. The method of claim 23 , further comprising transmitting information based on the sensed pressure level to an implantable stimulator via wireless telemetry, and adjusting electrical stimulation delivered to the patient based on the transmitted information.
27. The method of claim 23 , further comprising transmitting information based on the sensed pressure level to an external programmer via wireless telemetry, wherein the external programmer adjusts stimulation delivered by an implantable stimulator based on the transmitted information.
28. The method of claim 23 , wherein the first and second flexible tubes extend from a sensor housing, the method further comprising:
mounting the sensor housing within a bladder of the patient;
positioning the first flexible tube to extend downward from the bladder and through the urinary sphincter; and
positioning the second flexible tube to extend downward from the bladder and into the urethra below the urinary sphincter.