Low amplitude rhythmic contraction frequency in human detrusor strips correlates with phasic intravesical pressure waves

High-Performing and Capacitive-Matched Triboelectric Implants Driven by Ultrasound

In implantable bioelectronics, which aim for semipermanent use of devices, biosafe energy sources and packaging materials to protect devices are essential elements. However, research so far has been conducted in a direction where they cannot coexist. Here, the development of capacitance-matched triboelectric implants driven is reported by ultrasound under 500 mW cm-2 safe intensity and realize a battery-free, miniatured, and wireless neurostimulator with full titanium (Ti) packaging. The triboelectric implant with high dielectric composite, which has ultralow output impedance, can efficiently deliver sufficient power to generate the stimulation pulse without an energy-storing battery, despite ultrasound attenuation due to the Ti, and has the highest energy transmission efficiency among those reported so far. In vivo study using a rat model demonstrated that the proposed device system is an effective solution for relieving urinary symptoms. These achievements provide a significant step toward permanently implantable devices for controlling human organs and treating various diseases.

Objective Quantification of Detrusor Overactivity Using Spectral Measures of Cystometry Data

OBJECTIVE

To develop scalable objective methods for differentiating patients with and without detrusor overactivity (DO) using quantitative Fast Fourier Transform (FFT)-based measures and routinely captured cystometry data.

METHODS

Retrospective cystometry data were collected as prevoid vesical and abdominal pressure signals from 18 DO and 10 SUI (non-DO) cystometry recordings. Data were filtered and divided into two equal-duration segments, Early and Late Fill, representing the first and second halves of filling. FFT was applied, followed by subtraction of abdominal spectra from vesical spectra. Spectral Power (SP) and Weighted Average Frequency (WAF) measures were calculated for each segment spectra within 1-6 cycles min^-1.

RESULTS

Compared to non-DO, the mean SP was significantly higher in DO patients for both Early and Late Fill segments. WAF was significantly lower in DO patients for both segments. Changes in spectral pressures appeared to be linked to the presence of detrusor contractions (DCs) and were especially visible when DCs were present in the Early Fill segments of cystometry.

CONCLUSION

FFT-based spectral measures derived from routinely captured cystometry data are significantly different between DO and non-DO patients. This preliminary method is clinically scalable and can be further developed to facilitate the detection of DO, classify disease phenotype, and capture therapeutic efficacy.

Current developments in artificial intelligence from obstetrics and gynecology to urogynecology

In today's medical practice clinicians need to struggle with a huge amount of data to improve the outcomes of the patients. Sometimes one clinician needs to deal with thousands of ultrasound images or hundred papers of laboratory results. To overcome this shortage, computers get in help of human beings and they are educated under the term "artificial intelligence." We were using artificial intelligence in our daily lives (i.e., Google, Netflix, etc.), but applications in medicine are relatively new. In obstetrics and gynecology, artificial intelligence models mostly use ultrasound images for diagnostic purposes but nowadays researchers started to use other medical recordings like non-stress tests or urodynamics study results to develop artificial intelligence applications. Urogynecology is a developing subspecialty of obstetrics and gynecology, and articles about artificial intelligence in urogynecology are limited but in this review, we aimed to increase clinicians' knowledge about this new approach.

Measurement and Quantification of Cystometric Bladder Pressure Spectra in an in-vivo Sheep Model: A Feasibility Study

Cystometry is a standard procedure for the clinical evaluation of lower urinary tract disorders such as detrusor overactivity (DO). The utility of this procedure for DO diagnosis, however, is limited by the use of physician observations of bladder contractions and patient reported filling sensations. Although a number of preclinical and clinical studies have observed and developed methods to characterize bladder pressure dynamics, these techniques have not been scaled for routine clinical application. The goal of this study was to evaluate the feasibility of using an awake large animal model to characterize bladder pressure signals from cystometry as bladder pressure spectra and quantify changes in spectra during bladder filling. Two adult female sheep were trained for quiet catheterization in a minimally supportive sling and underwent multiple awake and limited anesthetized cystometry tests. In each test, bladder pressure was measured during continuous filling or with filling that included periods of no filling (constant volume). A Fast-Fourier Transform (FFT)-based algorithm was then used to quantify changes in pre-voiding bladder pressure spectra. Changes in Spectral Power (SP) and Weighted Average Frequency (WAF) were calculated during filling. To visualize temporal changes in bladder pressure frequencies during filling, Continuous Wavelet Transform (CWT) was also applied to cystometry data. Results showed that a significant increase in SP and decrease in WAF were both associated with bladder filling. However, during awake constant volume tests, SP significantly increased while changes in WAF were nonsignificant. Anesthetized tests demonstrated comparable values to awake tests for WAF while SP was considerably reduced. CWT facilitated visualization of spectral changes associated with SP and WAF as well as apparent non-voiding contractions during awake and anesthetized volume tests.Clinical Relevance-Bladder pressure spectra during cystometry are detectable in sheep and the changes during filling are similar to those observed in human retrospective clinical data. Sheep cystometry may be a valuable testbed for establishing and testing quantitative pressure spectra for use as a clinical diagnostic tool.

Artifacts and abnormal findings may limit the use of asymptomatic volunteers as controls for studies of multichannel urodynamics

BACKGROUND

Multichannel urodynamics is the gold standard for the evaluation of lower urinary tract symptoms (LUTS). When performing studies to validate new adjuncts to urodynamic testing with control patients undergoing urodynamic investigation, there is difficulty in the interpretation of urodynamic results in the asymptomatic patient due to artifacts and the invasive nature of the procedure. The purpose of this investigation was to examine urodynamics in asymptomatic volunteers in order to better understand the role of control participants in urodynamic research studies.

METHODS

Asymptomatic volunteers with no LUTS were recruited to undergo standard urodynamic testing as a comparison group in a study evaluating novel urodynamic techniques. To be eligible, participants had to report no LUTS, score ≤1 on all symptom questions of the International Consultation on Incontinence Questionnaire Overactive Bladder Module (ICIq-OAB) survey, have no medical conditions or to undergo any medications that affect bladder function. The urodynamics was done according to ICS standards. All tracings were evaluated by an expert neuro-urologist. Data were analyzed categorically for the presence or absence of low compliance (<30 mL/cmH20), detrusor overactivity, bladder outlet obstruction (Bladder Outlet Obstruction Index [BOOI]>40), weak contractility (bladder contractility index [BCI]<100), straining to void, poorly sustained detrusor contraction, uncoordinated EMG activity, and intermittent flow.

RESULTS

A total of 24 participants completed the study including 10 men and 14 women. All participants had at least 1 urodynamic abnormality/artifact with an average of 4.43±1.28 abnormalities/participant. The most common abnormalities included uncoordinated electromyography (EMG) activity (87.50%), straining to void (79.17%), and intermittent flow (70.83%). There were no significant differences for sex, age, Body Mass Index.

CONCLUSIONS

This study demonstrated that healthy, asymptomatic volunteers have high rates of abnormal urodynamic findings, suggesting that asymptomatic participants are not the ideal controls in research studies that involve urodynamic testing.

Artificial intelligence in functional urology: how it may shape the future

PURPOSE OF REVIEW

The aim of the present manuscript is to provide an overview on the current state of artificial intelligence (AI) tools in either decision making, diagnosis, treatment options, or outcome prediction in functional urology.

RECENT FINDINGS

Several recent studies have shed light on the promising potential of AI in functional urology to investigate lower urinary tract dysfunction pathophysiology but also as a diagnostic tool by enhancing the existing evaluations such as dynamic magnetic resonance imaging or urodynamics. AI may also improve surgical education and training because of its automated performance metrics recording. By bringing prediction models, AI may also have strong therapeutic implications in the field of functional urology in the near future. AI may also be implemented in innovative devices such as e-bladder diary and electromechanical artificial urinary sphincter and could facilitate the development of remote medicine.

SUMMARY

Over the past decade, the enthusiasm for AI has been rising exponentially. Machine learning was well known, but the increasing power of processors and the amount of data available has provided the platform for deep learning tools to expand. Although the literature on the applications of AI technology in the field of functional urology is relatively sparse, its possible uses are countless especially in surgical training, imaging, urodynamics, and innovative devices.

Bladder wall micromotion measured by non-invasive ultrasound: initial results in women with and without overactive bladder

OBJECTIVE

Rhythmic contractions of the bladder wall during filling result from the synchronization of bladder wall micromotion and are often observed in the urodynamic tracings of individuals with urinary overactive bladder (OAB). This study's objective was to develop a novel, non-invasive method to measure bladder wall micromotion and to conduct an initial study to test the hypothesis that elevated micromotion is associated with OAB.

METHODS

This prospective study enrolled women with OAB and asymptomatic volunteers as measured by the ICIQ-OAB survey. After filling the bladder to 40% cystometric capacity, 85 second cine-loops were obtained using a GE Voluson E8 ultrasound system with an 8 MHz curved, abdominal probe. A custom correlation-based texture tracking MATLAB algorithm was used to measure changes in the bladder wall thickness over time and correlate with changes in vesical pressure. Significant bladder wall micromotion was defined as changes in wall thickness with amplitudes higher than 0.1 mm in the frequency range of 1.75-6 cycles/minute as calculated from Fast Fourier Transform (FFT) analysis. The micromotion algorithm was tested on 30 women including 17 with OAB and 13 asymptomatic volunteers.

RESULTS

Micromotion was identified in 41% of subjects with OAB and 0% of asymptomatic volunteers, indicating a significant association of micromotion with OAB (Fisher's exact test, P=0.010). Micromotion was also found to have a significant association with a clinical diagnosis of detrusor overactivity (Fisher's exact test, P=0.031). Frequencies with elevated micromotion correlated with frequencies of vesical pressure fluctuations.

CONCLUSIONS

The feasibility of a non-invasive method to measure bladder wall micromotion was demonstrated using transabdominal anatomical motion mode (M-mode) ultrasound. Presence of micromotion was significantly associated with OAB and with urodynamic-identified rhythm.

Comparative-fill urodynamics in individuals with and without detrusor overactivity supports a conceptual model for dynamic elasticity regulation

AIMS

Dynamic elasticity was previously identified in individuals with overactive bladder (OAB) using comparative-fill urodynamics (UD) and is a biomechanical mechanism for acutely regulating detrusor wall tension. On the basis of this data, a conceptual model of dynamic elasticity regulation mediated through a balance of passive mechanisms and active contractions was constructed. The present study tested this model by determining whether individuals with detrusor overactivity (DO) exhibit less dynamic elasticity than individuals without DO.

METHODS

Individuals with and without urgency based on International Consultation on Incontinence Questionnaire-OAB surveys were prospectively enrolled in a comparative-fill UD study. An initial fill defined the presence or absence of DO and determined cystometric capacity. Three additional fills were employed with either passive emptying via a catheter or active voiding. To identify dynamic elasticity, average filling pressures (P_ves ) were compared for fill 1 (before strain softening), fill 2 (after strain softening), and fill 3 (after active void). A dynamic elasticity index was defined.

RESULTS

From 28 participants, those without DO showed decreased P_ves during filling after strain softening and restored P_ves during filling following active voiding, revealing dynamic elasticity. Participants with DO did not show dynamic elasticity. A dynamic elasticity index less than 1.0 cmH₂ O/40% capacity was identified in 2 out of 13 participants without DO and 9 out of 15 with DO, revealing a significant association between DO and reduced/absent dynamic elasticity (P = .024).

CONCLUSIONS

This study supports a conceptual model for dynamic elasticity, a mechanism to acutely regulate detrusor wall tension through a balance of competing active contractile and passive strain mechanisms. Improved understanding of this mechanistic model may help us to identify novel treatment strategies for OAB.

Are there different patterns of detrusor overactivity which are clinically relevant? ICI-RS 2018

INTRODUCTION

Different patterns of detrusor overactivity (DO) have been described and included in several standardization terminology documents. However, it is unclear if these different patterns have any clinical significance.

METHODS

This is a report of the proceedings of Proposal 3: "Are there different patterns of detrusor overactivity which are clinically relevant?" from the annual International Consultation on Incontinence-Research Society (ICIRS) meeting, which took place from 14 to 16 June 2018, in Bristol, UK.

RESULTS

We have collected and discussed, as a committee, the evidence about different urodynamic (UD) patterns of detrusor overactivity and their potential clinical significance. We reviewed the important previous basic research and clinical studies and compiled summaries. The discussion focused on clinical relevance of different UD patterns of DO and what further research is required.

CONCLUSIONS

There are several UD definitions of patterns of detrusor overactivity, however the clinical relevance of these definitions remains unclear. Future research should concentrate on defining the pattern of DO in relation to clinical diagnosis, gender, age, and treatment outcomes.

New Diagnostics for Male Lower Urinary Tract Symptoms

PURPOSE OF REVIEW

Lower urinary tract symptoms (LUTS) is a common constellation of symptoms that affect the aging male population with an astonishing prevalence. New technology and new uses of established technology are being used to help further evaluate LUTS in the male population and help guide treatment options. This review focuses on the developments and future directions in diagnostic modalities for evaluation of male LUTS, focusing on evaluation of both the filling and voiding phases of micturition.

RECENT FINDINGS

New techniques in evaluating the voiding phase include penile cuff test, external pressure sensing condom catheter, ultrasound measurement of detrusor wall thickness, ultrasound measurement of intravesical prostatic protrusion, doppler ultrasound and NIRS technology. Evaluation of the filling phase is still undergoing much development and requires additional validation studies. The techniques undergoing evaluation include sensation meters during UDS, assessing bladder micromotion and wall rhythm, assessing detrusor wall biomechanics, ultrasound measurement of detrusor wall thickness, pelvic doppler ultrasound, as well as functional brain imaging including fNIRS and fMRI.

SUMMARY

The development of novel, non-invasive, diagnostic tools have the potential for better evaluation of LUTS with earlier and enhanced treatments. This will likely improve the quality of life for men with LUTS.

Automated quantification of low amplitude rhythmic contractions (LARC) during real-world urodynamics identifies a potential detrusor overactivity subgroup

Objectives

Detrusor overactivity (DO) is characterized by non-voiding detrusor smooth muscle contractions during the bladder filling phase and often contributes to overactive bladder. In some patients DO is observed as isolated or sporadic contractions, while in others DO is manifested as low amplitude rhythmic contractions (LARC). The aim of this study was to develop an objective method to quantify LARC frequencies and amplitudes in urodynamic studies (UDS) and identify a subgroup DO of patients with LARC.

Methods

An automated Fast Fourier Transform (FFT) algorithm was developed to analyze a 205-second region of interest of retrospectively collected “real-world” UDS ending 30 seconds before voiding. The algorithm was designed to identify the three largest rhythmic amplitude peaks in vesical pressure (P_ves) in the 1.75–6 cycle/minute frequency range. These peak P_ves amplitudes were analyzed to determine whether they were 1) significant (above baseline P_ves activity) and 2) independent (distinct from any in abdominal pressure (P_abd) rhythm).

Results

95 UDS met criteria for inclusion and were analyzed with the FFT algorithm. During a blinded visual analysis, a neurourologist/urodynamicist identified 52/95 (55%) patients as having DO. The FFT algorithm identified significant and independent (S&I) LARC in 14/52 (27%) patients with DO and 0/43 patients (0%) without DO, resulting in 100% specificity and a significant association (Fischer’s exact test, p<0.0001). The average slowest S&I LARC frequency in this DO subgroup was 3.20±0.34 cycles/min with an amplitude of 8.40±1.30 cm-H₂O. This algorithm can analyze individual UDS in under 5 seconds, allowing real-time interpretation.

Conclusions

An FFT algorithm can be applied to “real-world” UDS to automatically characterize the frequency and amplitude of underlying LARC. This algorithm identified a potential subgroup of DO patients with LARC.