1. Accessible Incontinence Control Device
Biomedical Engineering Senior Design Group 17: Zach Hawkins1, Kristen Heck1, Amy Klemm1, Amanda Streff1
Advisors: Professor Paul King1, Dr. Doug Milam2, Dr. John Enderle3
1Vanderbilt University School of Engineering, 2Vanderbilt University Medical Center Urologic Surgery, 3University of Connecticut School of Engineering
Abstract
Purpose
Design an accessible incontinence control device that will comply with industry standards, can remain indwelling, and is easily operated. The goal was to improve on the current gold standard to better assist patients with other disabilities.
Methods
The device is operated by pressing a button to send a signal to an RC receiver. The receiver sends a signal to the servo which rotates, pushing the plunger. The increased pressure pushes the plunger attached to the other end of the tubing, collapsing the urethra. Another press of the button will release the plunger allowing for urine to flow.
Conclusion
Once the device is biocompatible and the status indicator is integrated with the device, it can be implanted for patient use.
How It Works
First, the cuff is secured around the urethra.
To close the urethra:
The user pushes up on the radio controller throttle stick to send a signal to the RC receiver.
A second signal is sent from the receiver to the servo.
The servo rotates clockwise pushing the miniature plunger down similar to how a piston moves.
The pressure increase in the tubing forces the second plunger in the cuff to move, compressing the urethra.
The device will remain in this position preventing urine flow until the device is activated again using the radio controller.
To open the urethra:
The signal will cause the servo to rotate counterclockwise pulling the plunger up and causing a decrease in pressure in the tubing.
The second plunger releases pressure on the urethra allowing urine to flow out of the bladder.
Inspiration & Goals
Inspired by the current gold standard,
the AMS 800 (pictured on the right)
Manually operated pump
Pumping releases pressure in cuff.
Cuff is refilled with saline from the pressure
reservoir
Goals
Comply with industry standards for urological medical devices
Be able to remain indwelling for 30 days
Easily operated by patient with disabilities
Allow emptying of the bladder when desired
Prevent urine flow when not desired
Provide an indication of the status of the bladder.
Changes to assist patients with dexterity issues
Pump eliminated.
A radio controlled servo increases and
decreases the pressure within a fluid filled
tube
The pressure causes a plunger to close off
the urethra
Background
Figure 1: (A) Device (B) Servo (C) Top view of open cuff (D) Side view of open cuff (E) Drawing of device including RC receiver, battery, and controller
*drawing not to scale
Our Device A B C D E
Conclusions
Accomplished the following design goals:
Push button operation makes it easier for patients with
disabilities to use.
Empties and prevents urine flow the bladder when desired.
The potential to be implanted in a patient, thus be indwelling for well over 30 days.*
Comply with industry standards for urological medical devices.*
*with minor modifications
Future Directions
Further miniaturize the device
Coat the entire device in silicone to ensure biocompatability
The external button should be equipped with an interface to display the bladder volume status
Safety and Cost Estimate
Safety Issues
Urethral erosion
Excessive pressure
Biocompatibility
Electrical hazard (i.e. shock)
Battery malfunction
Circuit error
Improper sealing
$95.70
Total
-----
Tubing
0.21
10ml syringe
0.19
3ml syringe (2)
20.00
Battery
8.50
Crystal
34.90
RF receiver
31.90
Servo
Cost
Supplies
Urinary Anatomy
Internal urethral sphincter:
involuntary
External urethral sphincter:
voluntary
Bladder: empty- a deflated
balloon, full-a pear shape that
rises in the abdominal cavity.
Normal function
Urine made by kidneys, travels through the ureters to the bladder.
Bladder stretches to accommodate filling.
At approximately cc, stretch receptors in the bladder wall send a signal to the nervous system.
Detrusor muscle in the bladder wall contracts and internal urinary sphincter relaxes.
The external sphincter contracts until the individual consciously relaxes it to void usually every 4-12 hours.
Types of Urinary Incontinence
Urge: Involuntary loss of urine associated with abrupt and strong desire to void
Stress: Involuntary loss of urine during coughing, sneezing, laughing, etc.
Overflow: Involuntary loss of urine associated with over distension of bladder
Functional Incontinence: No recognition of need to void, inability to make it to the toilet in time