Advances in Ambulatory Urodynamics

From wires to waves, a novel sensor system for in vivo pressure monitoring

Pressure monitoring in various organs of the body is essential for appropriate diagnostic and therapeutic purposes. In almost all situations, monitoring is performed in a hospital setting. Technological advances not only promise to improve clinical pressure monitoring systems, but also engage toward the development of fully implantable systems in ambulatory patients. Such systems would not only provide longitudinal time monitoring to healthcare personnel, but also to the patient who could adjust their way-of-life in response to the measurements. In the past years, we have developed a new type of piezoresistive pressure sensor system. Different bench tests have demonstrated that it delivers precise and reliable pressure measurements in real-time. The potential of this system was confirmed by a continuous recording in a patient that lasted for almost a day. In the present study, we further characterized the functionality of this sensor system by conducting in vivo implantation experiments in nine female farm pigs. To get a step closer to a fully implantable system, we also adapted two different wireless communication solutions to the sensor system. The communication protocols are based on MICS (Medical Implant Communication System) and BLE (Bluetooth Low Energy) communication. As a proof-of-concept, implantation experiments in nine female pigs demonstrated the functionality of both systems, with a notable technical superiority of the BLE.

Lower Urinary Tract Symptoms in Young Men-Causes and Management

PURPOSE OF REVIEW

This review explores the subject of lower urinary tract symptoms (LUTS) in young men.

RECENT FINDINGS

Young men (aged 39 or younger) can be affected by a variety of conditions that can cause LUTS. Approximately half of young men report LUTS. Storage or "irritative" voiding symptoms are nearly twice as common as "obstructive" symptoms in young men. Infectious or inflammatory causes such as prostatitis are the most common cause of LUTS in this age group, while other etiologies include urethral strictures, primary bladder neck obstruction, as well as neurogenic and non-neurogenic bladder dysfunction. A thorough clinical evaluation is critical for determining the correct diagnosis and directing the appropriate treatment plan. Young men experience lower urinary tract symptoms at relatively high rates. Clinical treatments range from behavioral therapy to medications and/or surgical interventions. Ambulatory urodynamics and wearable sensors may provide more accurate and real-world diagnostic assessment of bladder dysfunction in this relatively under-studied group. More study is needed to characterize the disease burden and impact in this specific group of patients.

The Stockholm Spinal Cord Uro Study: 3. Urodynamic characteristics in a regional prevalence group of persons with spinal cord injury and indications for improved follow-up

AIMS

Examine the outcome of urodynamic studies in a regional prevalence group of patients with traumatic spinal cord injury (SCI), explore relationships between urodynamic parameters and renal complications/other SCI-related dysfunctions, assess the role of urodynamics in SCI follow-up.

METHODS

In a cross-sectional study, 211 patients were included, who attended a yearly check-up and had urodynamics performed as part of the follow-up in addition to S-creatinine, S-cystatin-C, renal ultrasound, and a questionnaire regarding complications. Relationships between urodynamic parameters and renal complications/other SCI-related dysfunctions were explored by descriptive and comparative statistics.

RESULTS

Neurogenic detrusor overactivity (NDO) was found in 150, underactive/acontractile detrusor in 44, normal detrusor function in 17 patients. Maximum detrusor pressures during filling/voiding in NDO attained mean levels of >40 cm H₂O in 68% of patients and >25 cm H₂O in 83%. Reduced compliance of the bladder wall, cystometric bladder capacity <250 mL, and detrusor overactivity leakage during filling were associated with higher detrusor pressures. Detrusor overactivity during more than one-third of the filling phase was significantly related to signs of renal complications among patients with SCI duration 11-20 years. No significant relationships were found between other urodynamic parameters and renal/other SCI-related complications. Renal complications in underactive/acontractile and normal detrusor function co-varied with evidence of previous NDO and other co-morbidities which may negatively influence kidney function.

CONCLUSIONS

Maximum detrusor pressures during the filling/voiding phases attained high levels in a majority of patients. Detrusor overactivity during more than one-third of the filling phase was significantly related to signs of renal complications.

A comprehensive survey on non-invasive wearable bladder volume monitoring systems

Measuring the volume of urine in the bladder is a significant issue in patients who suffer from the lack of bladder fullness sensation or have problems with timeliness getting to the restroom, such as spinal cord injury patients and some of the elderlies. Real-time monitoring of the bladder, therefore, can be highly helpful for urinary incontinence. Bladder volume monitoring technologies can be divided into two distinct categories of invasive and non-invasive. In invasive techniques, a catheter is directly inserted into the urethra to measure the amount of urine accurately. However, it is painful, limits the user's ordinary movements, and may hurt the urinary tract. Current non-invasive techniques measure the volume of the bladder from the skin using different stationary or portable apparatus at health centers. Both techniques have difficulties and are not cost-effective to use for a long period. Recently, both invasive and non-invasive methods have been attempted to be produced in the form of wearable devices utilizing different sensing and communication technologies. Wearable bladder monitoring devices can be easily used by patients with no or few clinical steps, making them much more affordable than non-wearable devices. While wearable devices seem to be a highly convenient and effective solution, they suffer from few drawbacks, such as relatively low precision. Hence, a great number of studies have been conducted to address these issues. In this article, we review and discuss non-invasive and minimally invasive methods for monitoring the bladder volume. We focus on the most practical and state-of-the-art methods employed in wearable devices, classify them by engineering and medical characteristics, and investigate their specifications, architectures, and measurement algorithms. This study aims to introduce the latest advances in this field to practitioners while comparing the advantages and disadvantages of existing approaches. Our study concludes with open problems and future trends in the area of bladder monitoring and measurement systems. Graphical abstract Wearable bladder monitoring system.