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Implantable Bladder Sensors: A Methodological Review.

Dakurah MN, Koo C, Choi W, Joung YH - Int Neurourol J (2015)

Bottom Line: With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced.However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder.We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Control Engineering, Hanbat National University, Daejeon, Korea.

ABSTRACT
The loss of urinary bladder control/sensation, also known as urinary incontinence (UI), is a common clinical problem in autistic children, diabetics, and the elderly. UI not only causes discomfort for patients but may also lead to kidney failure, infections, and even death. The increase of bladder urine volume/pressure above normal ranges without sensation of UI patients necessitates the need for bladder sensors. Currently, a catheter-based sensor is introduced directly through the urethra into the bladder to measure pressure variations. Unfortunately, this method is inaccurate because measurement is affected by disturbances in catheter lines as well as delays in response time owing to the inertia of urine inside the bladder. Moreover, this technique can cause infection during prolonged use; hence, it is only suitable for short-term measurement. Development of discrete wireless implantable sensors to measure bladder volume/pressure would allow for long-term monitoring within the bladder, while maintaining the patient's quality of life. With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced. However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder. Here, we explore the various types of implantable bladder sensors and current efforts to solve issues like hermeticity, biocompatibility, drift, telemetry, power, and compatibility issues with popular imaging tools such as computed tomography and magnetic resonance imaging. We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.

No MeSH data available.


Related in: MedlinePlus

Bladder volume sensing using a strain sensor (A: adapted from Rajagopalan S, et al. Sensors 2008;8:5081-95 [14], on the basis of Open Access) and a reed switch and magnet (B: adapted from Dreher RD, et al. IEEE Trans Biomed Eng 1972;19:247-8 [6], with permission of the Institute of Electrical and Electronics Engineers).
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f1-inj-19-3-133: Bladder volume sensing using a strain sensor (A: adapted from Rajagopalan S, et al. Sensors 2008;8:5081-95 [14], on the basis of Open Access) and a reed switch and magnet (B: adapted from Dreher RD, et al. IEEE Trans Biomed Eng 1972;19:247-8 [6], with permission of the Institute of Electrical and Electronics Engineers).

Mentions: Earlier attempts at bladder urine volume sensing were performed by measuring the bioelectric impedance difference between electrodes sutured to the detrusor muscle on opposite sides of the bladder as one arm of a resistor-capacitor phase shift oscillator. This oscillator functioned as a transponder, transmitting the changes in wave frequency, as a result of bladder filling, to an external receiver. However, encapsulation of these electrodes by fibrotic tissue growth demanded the need for frequent calibration, thereby hindering its feasibility in clinical application [5]. To avoid biofouling, Dreher et al. [6] presented an alternative method of bladder urine volume sensing that used a reed switch and a magnet sutured to the detrusor muscle in close proximity to one another. As the urinary bladder volume rises, the distance between the magnet and the reed switch is increased until the switch opens, thus activating a telemetry oscillator as shown in Fig. 1 [6]. This system operated on the assumptions that the musculature of the bladder is elastic and behaves like a balloon being filled. However, healthy urinary bladder muscle tissue is not flaccid under normal conditions and patients with a sensory paralytic bladder have chronic overdistension and flaccid bladders [7]. Furthermore, both of these methods require surgical intervention and are accompanied by postsurgical pain, long recovery time, and additional costs of healthcare.


Implantable Bladder Sensors: A Methodological Review.

Dakurah MN, Koo C, Choi W, Joung YH - Int Neurourol J (2015)

Bladder volume sensing using a strain sensor (A: adapted from Rajagopalan S, et al. Sensors 2008;8:5081-95 [14], on the basis of Open Access) and a reed switch and magnet (B: adapted from Dreher RD, et al. IEEE Trans Biomed Eng 1972;19:247-8 [6], with permission of the Institute of Electrical and Electronics Engineers).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4582084&req=5

f1-inj-19-3-133: Bladder volume sensing using a strain sensor (A: adapted from Rajagopalan S, et al. Sensors 2008;8:5081-95 [14], on the basis of Open Access) and a reed switch and magnet (B: adapted from Dreher RD, et al. IEEE Trans Biomed Eng 1972;19:247-8 [6], with permission of the Institute of Electrical and Electronics Engineers).
Mentions: Earlier attempts at bladder urine volume sensing were performed by measuring the bioelectric impedance difference between electrodes sutured to the detrusor muscle on opposite sides of the bladder as one arm of a resistor-capacitor phase shift oscillator. This oscillator functioned as a transponder, transmitting the changes in wave frequency, as a result of bladder filling, to an external receiver. However, encapsulation of these electrodes by fibrotic tissue growth demanded the need for frequent calibration, thereby hindering its feasibility in clinical application [5]. To avoid biofouling, Dreher et al. [6] presented an alternative method of bladder urine volume sensing that used a reed switch and a magnet sutured to the detrusor muscle in close proximity to one another. As the urinary bladder volume rises, the distance between the magnet and the reed switch is increased until the switch opens, thus activating a telemetry oscillator as shown in Fig. 1 [6]. This system operated on the assumptions that the musculature of the bladder is elastic and behaves like a balloon being filled. However, healthy urinary bladder muscle tissue is not flaccid under normal conditions and patients with a sensory paralytic bladder have chronic overdistension and flaccid bladders [7]. Furthermore, both of these methods require surgical intervention and are accompanied by postsurgical pain, long recovery time, and additional costs of healthcare.

Bottom Line: With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced.However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder.We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Control Engineering, Hanbat National University, Daejeon, Korea.

ABSTRACT
The loss of urinary bladder control/sensation, also known as urinary incontinence (UI), is a common clinical problem in autistic children, diabetics, and the elderly. UI not only causes discomfort for patients but may also lead to kidney failure, infections, and even death. The increase of bladder urine volume/pressure above normal ranges without sensation of UI patients necessitates the need for bladder sensors. Currently, a catheter-based sensor is introduced directly through the urethra into the bladder to measure pressure variations. Unfortunately, this method is inaccurate because measurement is affected by disturbances in catheter lines as well as delays in response time owing to the inertia of urine inside the bladder. Moreover, this technique can cause infection during prolonged use; hence, it is only suitable for short-term measurement. Development of discrete wireless implantable sensors to measure bladder volume/pressure would allow for long-term monitoring within the bladder, while maintaining the patient's quality of life. With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced. However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder. Here, we explore the various types of implantable bladder sensors and current efforts to solve issues like hermeticity, biocompatibility, drift, telemetry, power, and compatibility issues with popular imaging tools such as computed tomography and magnetic resonance imaging. We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.

No MeSH data available.


Related in: MedlinePlus