ICS teaching module: Ambulatory urodynamic monitoring

Catheter-Free Urodynamics Testing: Current Insights and Clinical Potential

Lower urinary tract dysfunction not only interferes with the health-related quality of life of patients but may also lead to acute kidney injury and infections. To assess the bladder, urodynamic studies (UDS) have been implemented but the use of catheters leads to discomfort for the patient. Catheter-free long-term UDS would be useful and a potential solution could be ambulatory wireless devices that communicate via telemetry. Such sensors can detect pressure or volume. Numerous types of potential catheter-free sensors have been proposed for bladder monitoring. Despite substantial innovation in the manufacturing of implantable biomedical electronic systems, such sensors have remained at the laboratory stage due to a number of critical challenges. These challenges primarily concern hermeticity and biocompatibility, sensitivity and artifacts, drift, telemetry, and energy management. Having overcome these challenges, catheter-free ambulatory urodynamic monitoring could combine a synchronized intravesical pressure sensor with a volume analyzer but only the steps of cystometry and volume measurement are currently sufficiently reproducible to simulate UDS results. The measurement of volume by infrared optical sensors, in the form of abdominal patches, appears to be promising and studies are underway to market a telemetric ambulatory urodynamic monitoring system that includes an intravesical pressure sensor. There has been considerable progress in wearable and conformable electronics on many fronts, and continued collaboration between engineers and urologists could quickly overcome current challenges. In addition, to the diagnosis of UDS, such sensors could be useful in the development of a long-term closed-loop neuromodulation system. In this review, we explore the various types of catheter-free bladder sensors, inherent challenges and solutions to overcome these challenges, and the clinical potential of such long-term implantable sensors.

Nocturnal Bladder Function and Sleep in the Children with Refractory Nocturnal Enuresis: A Prospective Study

OBJECTIVE

To prospectively investigate the nocturnal bladder function and sleep in children with refractory primary monosymptomatic nocturnal enuresis (RPMNE).

MATERIALS AND METHODS

Fifty-three children diagnosed with RPMNE and 30 controls who had upper urinary tract abnormality but without any voiding problems were included in the study. RPMNE patients underwent a standardized investigation protocol, including the Pittsburgh Sleep Quality Index (PSQI) questionnaire, a 7-day bladder diary, and the simultaneous ambulatory urodynamic monitoring and polysomnography (PSG); controls were evaluated using the PSQI questionnaire and PSG.

RESULTS

The children with RPMNE were subdivided into the nocturnal detrusor overactivity (NDO) case group and the non-NDO case group. The children in the NDO case group had a higher percentage of total sleep time in light sleep and a lower percentage in the N3 sleep stage than those in the non-NDO case group and control group (P <.05). The cortical arousal index and PSQI scores of both RPMNE subgroups were higher compared to the control group (P <.05). The incidences of reduced nocturnal bladder capacity (NBC) in the NDO case group were higher than in the non-NDO case group (P <.05). The frequency of involuntary detrusor contractions during sleep was positively correlated with cortical arousal index in the NDO case group (r = 0.811, P <.0001).

CONCLUSION

In addition to the reduced NBC, the RPMNE is related to abnormal NDO, increased light sleep period, and cortical arousal dysfunction. Moreover, there is a certain correlation between the abnormal degrees of NDO and cortical arousal dysfunction.

Do the Ultrasonographic Measures of Midurethral Sling Location Relate With Surgical Outcomes?

IMPORTANCE

The proper placement of a midurethral sling (MUS) is the key factor for a successful surgical outcome.

OBJECTIVE

This study aimed to evaluate the relationship of perineal ultrasonographic measures of the tape location with subjective and objective outcomes after MUS surgery at midterm follow-up of women.

METHODS

The tape percentile (TP; total urethral length/bladder neck tape distance×100) and urethra tape distance (UTD; the shortest distance from the longitudinal smooth muscle complex of the urethra to the midpoint of the tape) were correlated with midterm surgical success. Patient satisfaction measured with the visual analog scale (VAS) was considered as the primary outcome. The presence of stress urinary incontinence on direct questioning, the Urinary Distress Inventory 6 (UDI-6) scores, findings of the cough stress test, free uroflowmetry, postvoid residual volume, and single-cycle voiding ambulatory urodynamic monitoring (AUM) were the other outcomes.

RESULTS

Seventy-eight women were evaluated at a mean follow-up of 4.4 ±3.3 years. Women who were highly satisfied (VAS ≥ 8) had a significantly higher TP (64.7% vs 50.8%, P < 0.001) and lower UTD (3.6 vs 4.5 mm, P = 0.018). Irritative, stress, and obstructive scores at UDI-6 increased as the tape was located closer to the bladder neck (P < 0.001, P < 0.001 and P = 0.044, respectively), and stress symptoms decreased with a tape closer to the urethra (P < 0.001). Women with detrusor overactivity at AUM were found to have a lower TP (P < 0.001).

CONCLUSION

The perineal ultrasonographic evaluation of tape location with UTD and TP seems to be well correlated with the women's midterm MUS surgical outcomes.

A Y-shape connection device for pediatric patients with an indwelling catheter (Dia = 8Fr) during urodynamic studies, especially for filling phase measurements: a single-center prospective study for safety and effectiveness

Introduction

This prospective study aimed to assess the effectiveness of a Y-shape connection device in reducing pain and bleeding in pediatric patients with indwelling catheters during urodynamic studies (UDS), while also obtaining effective results in the filling phase.

Methods

A total of 45 pediatric patients with a mean age of 13 years were included, all of whom underwent both a UDS with the Y-shape connection device (Method A) and a standard UDS procedure (Method B).

Results

The Y-shape connection device demonstrated similar overall urodynamic parameters compared to the standard procedure, while also resulting in significantly less bleeding (P = 0.006) and lower VAS scores during (1.12 ± 0.58 vs. 3.88 ± 1.01, P = 0.001) and after (0.12 ± 0.08 vs 2.91 ± 0.89, P = 0.001) the procedure. No adverse events were reported at the 1-month follow-up.

Discussion

These findings suggest that the Y-shape connection device can effectively reduce pain and bleeding during and after UDS in pediatric patients with indwelling catheters (Dia = 8Fr), while also obtaining effective results in the filling phase. Therefore, this Y-shape connection device has a more significant value for children who require urodynamic studies and place more emphasis on filling phase parameters.

Clinical trial registration

ChiCTR2300068280.

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.

Advances in Ambulatory Urodynamics

PURPOSE OF REVIEW

This manuscript reviews recent technological advances in ambulatory urodynamics.

RECENT FINDINGS

Ambulatory urodynamics is currently recommended by the International Continence Society as a second-line diagnostic tool in patients with nondiagnostic traditional urodynamics. Novel techniques involving telemetric monitoring are in development, which utilize catheter-free wireless systems to address several recognized shortcomings of inoffice urodynamic studies. Current research in catheter-free bladder pressure measurements involves either an intravesical, intradetrusor, or transdetrusor approach. Real-time bladder volume estimation may be performed using ultrasonography, near-infrared spectroscopy, or bladder volume conductance measurement. Ambulatory urodynamics can measure bladder function in the "real world" setting, capturing physiological bladder filling and emptying and allowing patients to reproduce the activities that may trigger their symptoms. Telemetric devices being developed represent further advances in this field and focus upon improving diagnostic capabilities, evaluating patient response to treatment, and facilitating closed-loop bladder control with neuroprosthetic integration.

Wireless intravesical device for real-time bladder pressure measurement: Study of consecutive voiding in awake minipigs

Traditional urodynamics have poor correlation with urological symptoms. Ambulatory urodynamics may improve this correlation but the need for a transurethral catheter and the time-consuming nature of this examination limits its use. Therefore, the objective of this study was to develop a wireless real-time bladder pressure measurement device for repeated and prolonged-term measurement of bladder behavior in awake pigs. The Bladder Pill is an intravesical device with a pressure microsensor and a 3-dimensional inductive coupling coil for energy supply. A corresponding external coil provides wireless power transmission and real-time communication of bladder pressure data. To test the correlation between the pressure data measured by the device and by standard methods, we compared static water column pressures with this device and water-filled urodynamic catheter systems. In vivo assessment of awake voiding by the pill was done by introducing the bladder pill into the bladder of Göttingen minipigs. An air-charged urodynamic catheter was introduced transurethrally as control for pressure measurements. The optimal physical configuration of the pill was investigated to maximize the containment in the bladder. We used two versions of external signal receivers (one waistband and one rectangular frame) to test the optimal external signal capture. Next to that, we performed short-term and medium-term comparative pressure studies. The in vitro static pressure measurement demonstrated a mean difference of less than 1 cm H₂O between the methods. The optimal design of the pill for maximal retainment in the bladder proved to be a pigtail configuration. The bending of the device during bladder contractions caused offset of 2.7 +/- 1.4 cm H₂O (mean +/- SD) on the pressure measurements. The rectangular frame performed signal capture during 5 consecutive voids with a good correlation of the pressure measurements. The device can be inserted through the urethra and is retrieved using string or endoscopic extraction. In conclusion, wireless long-term measurement of bladder pressure is demonstrated and yields comparable results to current available catheter methods of measurement in a pig model.

Ambulatory urodynamic monitoring: state of the art and future directions

Urodynamic studies are a key component of the clinical evaluation of lower urinary tract dysfunction and include filling cystometry, pressure-flow studies, uroflowmetry, urethral function tests and electromyography. However, pitfalls of traditional urodynamics include physical and emotional discomfort, artificial test conditions with catheters and rapid retrograde filling of the bladder, which result in variable diagnostic accuracy. Ambulatory urodynamic monitoring (AUM) uses physiological anterograde filling and, therefore, offers a longer and more physiologically relevant evaluation. However, AUM methods rely on traditional catheters and pressure transducers and do not measure volume continuously, which is required to provide context for pressure changes. Novel telemetric AUM (TAUM) methods that use wireless, catheter-free, battery-powered devices to monitor bladder pressure and volume while patients carry out their daily activities are currently being investigated. TAUM devices under current development are innovating in the areas of remote monitoring, rechargeable energy sources, device deployment and retrieval and materials engineering to provide increased diagnostic accuracy and improved comfort for patients with incontinence or voiding dysfunction. These devices hold promise for improving the diagnosis and management of patients with lower urinary tract disorders.

The Value of Ambulatory Urodynamics in the Evaluation of Treatment Effect of Sacral Neuromodulation

OBJECTIVES

To assess the improvement of symptoms by sacral neuromodulation (SNM) in an objective way by carrying out an ambulatory urodynamic study (ambulatory-UDS). Until now, successful treatment has been defined as a ≥50% improvement recorded on voiding diaries. Voiding diaries are a patient reported outcome tool. A tool with less bias is desired to evaluate the treatment results before an expensive permanent system is implanted.

METHODS

Between 2002 and 2015, a total of 334 patients with lower urinary tract symptoms were included consecutively in an ambulatory-UDS database. From this database, a subgroup of patients was selected which underwent SNM.

RESULTS

In 51 patients, an ambulatory-UDS was performed both at baseline and during the SNM test period. A positive treatment outcome after test stimulation based on the patients' voiding diary, correlated (p < 0.0001) with an improvement on ambulatory-UDS. Twenty-six of the 30 patients, who have showed improvement of more than 50% on voiding diary parameters and who had subjective improvement of their symptoms, showed an early improvement on ambulatory-UDS.

CONCLUSIONS

Ambulatory-UDS can be used in clinical decision making, as it is associated with voiding diary improvement during the SNM test period. Using ambulatory-UDS to confirm success could in the future justify the shortening of the test period.