Urodynamic after-contraction waves: a large observational study in an adult female population and correlation with bladder and ureter emptying functions in women

ICS-SUFU standard: Theory, terms, and recommendations for pressure-flow studies performance, analysis, and reporting. Part 2: Analysis of PFS, reporting, and diagnosis

AIMS

The Working Group (WG), initiated by the International Continence Society (ICS) Standardisation Steering Committee and supported by the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction, has revised the ICS Standard for pressure-flow studies of 1997.

METHODS

Based on the ICS standard for developing evidence-based standards, the WG developed this new ICS standard in the period from May 2020 to December 2022. A draft was posted on the ICS website in December 2022 to facilitate public discussion and the comments received have been incorporated into this final release.

RESULTS

The WG has recommended analysis principles for the diagnosis of voiding dysfunction for adult men and women without relevant neurological abnormalities. New standard terms and parameters for objective and continuous grading of urethral resistance (UR), bladder outflow obstruction (BOO) and detrusor voiding contraction (DVC) are introduced in this part 2 of the standard. The WG has summarized the theory and recommendations for the practice of pressure-flow study (PFS) for patients in part 1. A pressure-flow plot is recommended for the diagnosis of every patient, in addition to time-based graphs. Voided percentage and post void residual volume should always be included in PFS analysis and diagnosis. Only parameters that represent the ratio or subtraction of pressure and synchronous flow are recommended to quantify UR and only parameters that combine pressure and flow in a product or sum are recommended to quantify DVC. The ICS BOO index and the ICS detrusor contraction index are introduced in this part 2 as the standard. The WG has suggested clinical PFS dysfunction classes for male and female patients. A pressure-flow scatter graph including every patient's pdet at maximum flow (pdetQmax ) with maximum flow rate (Qmax ) point should be included in all scientific reports considering voiding dysfunction.

CONCLUSION

PFS is the gold standard used to objectively assess voiding function. Quantifying the dysfunction and grading of abnormalities are standardized for adult males and females.

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.

Detrusor after-contraction on ambulatory urodynamics in symptomatic women

OBJECTIVES

To investigate the association between detrusor after-contraction and urodynamic parameters in a cohort of patients undergoing urodynamic studies by ambulatory monitoring.

METHODS

All symptomatic adult female patients with non-neurogenic lower urinary tract dysfunction having ambulatory monitoring over the period January 1998 to January 2014 were included. Urodynamic traces were reviewed to identify detrusor after-contraction. Measured urodynamic variables were Qmax (mL/s), V(void) (mL) and P(det.Qmax) (cmH(2)O). Student's unpaired t-test was used to compare the mean of the variable in the detrusor after-contraction and non-detrusor after-contraction groups.

RESULTS

We identified 331 women with a median age of 50 years (range 16-82). Detrusor after-contraction was seen after at least one void in 122 patients giving a prevalence of 37%. A total of 167 (51%) patients had detrusor overactivity. Diagnosis of detrusor overactivity was associated with the presence of detrusor after-contraction (P < 0.05). Overall, patients with detrusor after-contraction had a statistically higher mean P(det.Qmax) (32 vs 28 cmH(2)O, P = 0.04) and lower mean voided volume (300 vs 378 mL, P < 0.001).

CONCLUSION

These findings suggest a relatively high prevalence of detrusor after-contraction during ambulatory monitoring, and an association between detrusor overactivity, V(void), P(det.Qmax) and detrusor after-contraction recorded during ambulatory monitoring. Therefore, a link between detrusor after-contractions and the syndrome of overactive bladder can be postulated.