Performance analysis of the T-DOC® air-charged catheters: An alternate technology for urodynamics

Subtotal fistulectomy and sliding anoderm flap: A new sphincter-sparing technique for anal fistula

AIM

The underlying causes of failure or recurrence after ligation of the intersphincteric fistula tract are postulated to be refistulization, breakdown of the closure wound in the intersphincteric plane and faecal contents entering the internal opening, thereby causing recurrent infection. The aim of this study is to demonstrate the outcomes of subtotal fistulectomy with sliding anoderm flaps to prevent refistulization.

METHOD

This retrospective study used prospectively collected data. Patients with transsphincteric or intersphincteric fistulas were enrolled between August 2021 and July 2023. An anal manometric study was performed before and after surgery. Faecal incontinence was evaluated using the faecal incontinence severity index (FISI). Failure was defined as nonhealing of the surgical wound or fistula.

RESULTS

Fifty-one patients who underwent subtotal fistulectomy with a sliding anoderm flap were included. After a median follow-up of 12 months (range 4-27 months), primary healing was achieved in 49 patients (96%). Two patients experienced treatment failure, while none developed postoperative recurrence. The median healing time was 10 weeks (range 6-24 weeks). The FISI scores did not change significantly after the surgery. The median resting pressure significantly reduced after surgery [125 cmH2O (range 59-204 cmH2O) vs. 99 cmH2O (range 36-176 cmH2O); p = 0.0001]. The median squeeze pressure significantly decreased after surgery [356 cmH2O (range 137-579 cmH2O) vs. 329 cmH2O (range 72-594 cmH2O; p = 0.005)].

CONCLUSION

Subtotal fistulectomy with a sliding anoderm flap showed excellent healing rates with no postoperative deterioration of anal function.

Comparison of Air-charged Catheter and Water-filled Catheter in Female Urethral Pressure Profile

OBJECTIVE

To compared the maximum urethral pressure (Pura@max) and functional urethral length (FUL) obtained with water-filled catheters and air-charged catheters during female urethral pressure profile (UPP) in a retrospective study.

PATIENTS AND METHODS

One hundred and five female patients were enrolled in our investigation. At Beijing Chao-Yang Hospital, patients who had lower urinary tract dysfunction underwent UPP using a modified UPP equipment. In one UPP, both a water-filled catheter (WFC) and an air-charged catheter (ACC) were employed simultaneously. The paired t test was used to compare the differences between the two systems. Bias and correlations between the two systems were analyzed according to the American Clinical and Laboratory Standardization Institute (CLSI) EP9-A3 recommendations.

RESULTS

There were 105 female participants in this study. The patients were 55.5 ± 14.2years old on average. By using the ACC and WFC systems, the mean FUL was determined to be 39.7 ± 16.2 mm and 33.9 ± 13.9 mm, respectively. The FUL findings of two systems differed significantly from one another (P < .01), and a linear fit with R2 = 0.94 indicates a strong linear correlation. The findings of the maximum urethral pressure (Pura@max) measurements made by the ACC and WFC systems, respectively, were 134.3 ± 39.1cmH2O and 99.2 ± 27.6cmH2O, are substantially different (P < .01), and the linear fit R2 = 0.67. The Pura@max of two systems did not linearly correlate with one another.

CONCLUSION

For UPP, ACCs often provide higher readings than WFCs, and there is a significant difference in the readings between the two systems. The pressure values derived from the two systems do not correlate, although the FUL does have a significant linear correlation. Results from the ACC and WFC cannot be used interchangeably.

The female urethra: urethral function throughout a woman's lifetime

INTRODUCTION AND HYPOTHESIS

The objective of this narrative review is to describe changes in urethral function that occur during a woman's lifetime. Evaluation of urethral function includes measurements of urethral closure pressure, at rest and during stress, leak point pressure, and the detailed study of anatomical and histological changes of the urethral sphincteric mechanism.

METHODS

A literature search in MEDLINE, PubMed, and relevant journals from 1960 until 2020 was performed for articles dealing with urethral function and the impact of aging, pregnancy, and childbirth, female hormones, and menopausal transition on the urethral sphincteric mechanism. Longitudinal and cross-sectional epidemiological surveys, studies on histological changes in urethral anatomy during aging, and urodynamic data obtained at different points in a woman's lifetime, during pregnancy, after childbirth, as well as the effects of female hormones on urethral sphincter function are reviewed. Relevant studies presenting objective data are analyzed and briefly summarized.

RESULTS AND CONCLUSIONS

The findings lead one to conclude that a constitutional or genetic predisposition, aging, and senescence are the most prominent etiological factors in the development of urinary incontinence and other pelvic floor disorders. Vaginal childbirth dilates and may damage the compressed pelvic supportive tissues and is invariably associated with a decline in urethral sphincter function. Pregnancy, hormonal alterations, menopausal transition, weight gain, and obesity are at best of secondary influence on the pathology of lower urinary tract dysfunction. The decline of circulating estrogens during menopausal transition may play a role in the transition of fibroblasts to cellular senescence.

Effect of posture on anorectal manometric measurements in female patients with fecal incontinence and rectoanal intussusception

PURPOSE

This study aimed to investigate the influence of erect position on anorectal manometry in patients with rectoanal intussusception (RAI).

METHODS

This was a single center prospective observational study. Eighty female patients with fecal incontinence (FI) who underwent defecography between 1st January 2016 and 30th April 2022 were included. The effect of posture on commonly measured parameters during manometry was assessed in the left-lateral and erect positions. The severity of FI was assessed using FI Severity Index (FISI).

RESULTS

Defecography showed that 30 patients had circumferential RAI (CRAI), and 50 had non-CRAI. There were no significant differences in age, parity, FI type, and FISI scores between the groups. However, FISI scores were significantly lower in 51 patients with passive FI than 12 patients with mixed FI type [21 (8-38) vs. 32 (8-43), P = 0.007]. Endo-anal ultrasound showed no significant difference in the incidence of sphincter defects between the groups. Maximum squeeze pressure was significantly lower in the erect position than in the left-lateral position in the CRAI patients [119 cm H₂O (59‒454 cm H₂O) vs. 145 cm H₂O (65‒604 cm H₂O), P = 0.006] however, this finding was not observed in the non-CRAI group and the subgroup of anterior RAI patients. In either group, maximum resting pressure, defecation desire volume, and maximum tolerated volume were significantly higher, while anal canal length was significantly shorter in the erect position than in the left-lateral position, respectively.

CONCLUSION

Voluntary contraction in female FI patients with CRAI was suppressed in the erect position.

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.

Head-to-head comparison of pressures during full cystometry, with clinical as well as in-depth signal-analysis, of air-filled catheters versus the ICS-standard water-filled catheters

Aims

To compare in vivo differences of two catheter systems for urodynamics to further discover their measurement properties.

Methods

Side‐by‐side catheterization with two catheters for intravesical and abdominal pressure during full cystometry in 36 prospectively recruited patients with analysis of mean and absolute differences at urodynamic events and post hoc in‐depth signal analysis comparing the full pressure traces of both systems.

Results

The mean pressure differences at urodynamic events between air‐filled and water‐filled systems are small, however, with a large variation, without a systematic difference. The majority of the intersystem differences are significantly larger than 5 cmH₂O. Further analysis showed that urodynamic event pressure differences of both systems at the start of the test were carried forward throughout the remainder of the test without subsequent or additional tendency to differ. Post hoc whole test signal analysis with pressures equalized from the first sample shows high cross‐correlation (>0.981) between the pressure signals per location (rectum and bladder) per test and almost zero‐time shift (<0.05 s) of all cystometry pressure samples.

Conclusions

We confirm earlier studies that showed random differences at events between air‐filled and water‐filled pressures during clinical urodynamic testing and confirm that these are intrinsic but not systematic—and still incompletely explained—offset‐baseline differences. We determined on closer full measurement analysis after equalizing, that both systems are similar in displaying urodynamic pressure variations and amplitudes. We also confirm that both systems require awareness of intrinsic measurement properties during urodynamic testing and especially may necessitate adjustment of pressure offsets into a quantitative diagnosis of a urodynamic test.

Usability and safety of the new 5 French air-charged catheter for performing urodynamic studies on pediatric patients

AIMS

To assess the performance and safety of the T-DOC® 5 French air-charged urodynamic catheters in pediatric patients and obtain feedback from providers related to usability performance.

METHODS

Patients ages 12 years and younger undergoing urodynamics were prospectively recruited from two institutions. The T-DOC® 5 French air-charged catheters were used. Issues with catheter placement, adverse events (AEs), and pain scores were assessed. A follow-up telephone call was made to assess for post-urodynamic AEs. Providers completed a clinical user questionnaire. Likert scale was used (1 = most negative and 5 = most positive response) and reported in mean (range).

RESULTS

A total of 28 patients completed the study. The mean age was 55 months (5-130) (10 females, 18 males). One problem was noted with the insertion of an abdominal catheter, secondary to stool impaction. Catheters stayed in place on all subjects, except for one related to patient hyperactivity. There were no AEs during the studies. In total four reported post-urodynamics AEs (one hematochezia, three dysuria). Among nine patients, pain level on the bladder and abdominal insertion was 3.6/10 (0-10) and 3.1/10 (0-10). Five providers completed the questionnaire. The overall ease of use was rated 4.3/5 (3-5). The ease of insertion was 4.1/5 (2-5) and set-up/clean-up time was 4.4/5 (3-5). Tracing stability, subtraction accuracy, and artifact sensitivity were all perceived favorably (respectively 4.8/5 [4-5], 4.6/5 [4-5], and 4.4/5 [4-5]).

CONCLUSIONS

The T-DOC® 5 French air-charged catheter was considered safe and effective in pediatric patients. No AEs occurred during the studies. Providers, using the catheters, reported favorably on catheter usage.

Novel implantable pressure and acceleration sensor for bladder monitoring

OBJECTIVES

To test the hypothesis that an implantable sensing system containing accelerometers can detect small-scale autonomous movements, also termed micromotions, which might be relevant to bladder physiology.

METHODS

We developed a 6-mm submucosal implant containing a pressure sensor (MS5637) and a triaxial accelerometer (BMA280). Sensor prototypes were tested by implantation in the bladders of Gottingen minipigs. Repeated awake voiding cystometry was carried out with air-charged catheters in a standard urodynamic set-up as comparators. We identified four phases of voiding similar to cystometry in other animal models based on submucosal pressure. Acceleration signals were separated by frequency characteristics to isolate linear acceleration from the baseline acceleration. The total linear acceleration was calculated by the root mean square of the three measurement axes. Acceleration activity during voiding was investigated to adjacent 1-s windows and was compared with the registered pressure.

RESULTS

We observed a total of 19 consecutive voids in five measurement sessions. A good correlation (r > 0.75) was observed between submucosal and catheter pressure in 14 of 19 premicturition traces. The peak-to-peak interval between maximum total linear acceleration was correlated with the interval between submucosal voiding pressure peaks (r = 0.760, P < 0.001). The total linear acceleration was higher during voiding compared with pre- and postmicturition periods (start of voiding/phase 1).

CONCLUSIONS

To the best of our knowledge, this is the first report of bladder wall acceleration, a novel metric that reflects bladder wall movement. Submucosal sensors containing accelerometers can measure bladder pressure and acceleration.

Truth or Myth: Intra-abdominal Pressure Increases in the Lithotomy Position

STUDY OBJECTIVE

To determine if there were differences in intra-abdominal pressure (IAP) in the supine, low lithotomy, and high lithotomy positions.

DESIGN

Prospective cohort study.

SETTING

University medical center.

PATIENTS

Twenty-nine women undergoing surgery for prolapse or stress incontinence.

INTERVENTIONS

Relevant medical history, including the pelvic organ prolapse quantification stage, body mass index, and airway grade (Mallampati score), was abstracted from patients' medical charts. IAP was measured in centimeters of water (cmH₂O) on the day of their surgery before induction of general or intravenous anesthesia using a T-doc air charged urodynamic catheter (Laborie Aquarius; Ontario, Canada) placed in a patient's vagina (for patients with incontinence) or rectum (for patients with prolapse).

MEASUREMENTS AND MAIN RESULTS

IAP was measured in 3 positions: supine (legs at 0°), low lithotomy (legs in Yellowfin stirrups at 45°; Allen Medical, Acton, MA), and high lithotomy (legs at 90°). The means ± SDs IAP for the groups were as follows: in the supine position, 18.6 cmH₂O ± 7.6; low lithotomy, 17.7 cmH₂O ± 6.6; and high lithotomy, 17.1 cmH₂O ± 6.3. In the same women, there was a significant decrease in IAP from the supine to high lithotomy positions, with a mean difference of 1.4 cmH₂O ± 3.7, p = .05. Similarly, there was a significant, though smaller, decrease in mean IAP when moving from the supine to low lithotomy positions in these same women (mean decrease of 0.9 cmH₂O ± 1.5, p = .004). Neither change is clinically significant based on previous research that suggests 5 cmH₂O is a clinically significant change.

CONCLUSION

Placing patients' legs in a low or high lithotomy position does not result in a clinically significant increase in IAP. Therefore, surgeons and anesthesiologists can consider positioning patients' lower extremities in stirrups while patients are awake to minimize discomfort and possibly reduce the risk of nerve injuries.

Influence of the urethral pressure transducer in measuring Valsalva leak point pressure in women undergoing multichannel urodynamic testing

AIMS

To determine if the air-charged urethral sensor balloon currently used in urodynamic testing (UDS) significantly impacts Valsalva leak point pressure (VLPP) measurements.

METHODS

This is a prospective cohort study of women undergoing UDS at an academic institution. VLPPs were obtained at 150 mL and urodynamic capacity with and without the urethral pressure sensor in the urethra. VLPP measurements were analyzed using a Wilcoxon signed-rank test. Median and interquartile range are presented.

RESULTS

Sixty-three patients were enrolled in the study, 53 were included in the primary analysis. The mean age of the subjects was 56.2 ± 12.1 years. Nine patients (16%) solely leaked when the balloon was not present in the urethra either with cough or during VLPP measurement. At both 150 mL and urodynamic capacity, when VLPP testing was performed, there was a significant difference (cmH₂ O) between the control and intervention values, (76.2 [55.0, 97.0] vs 68.8 [46.3, 93.3], P = .0012; 79.3 [53, 96.5] vs 72.5 [50.8, 92.3], P = .04). There was also a statistically significant difference between the control and intervention values for the lowest leak value at 150 mL and capacity (70.5 [51, 94.5] vs 60.0 [40, 88] P = .002; 73.5 [49.5, 91.5] vs 61 [45, 88], P = .017).

CONCLUSIONS

The higher VLPPs obtained with the urethral balloon in place indicate that the balloon may be the cause of falsely elevated VLPPs during urodynamic testing. Additionally, the balloon may mask a diagnosis of stress urinary incontinence in some patients.

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.

Differences between water-filled and air-charged urodynamic catheters for determining the urethral pressure profile in neurogenic lower urinary tract dysfunction patients

AIM

The maximum urethral closure pressure (MUCPs) and functional urethral length (FUL) obtained with water-filled and air-charged catheters during urethral pressure profile (UPP) determination was compared in a single, blind, randomized, and prospective trial.

METHODS

Thirty-three males with spinal cord injuries and neurogenic lower urinary tract dysfunction underwent UPP determinations using water-filled and air-charged catheters in random order; the patients were unaware of the catheter sequence. The variability of the same type of catheter and the agreement between the different types of catheters were compared. The Pearson correlation coefficient was used to check the correlation between the catheters and the Bland-Altman method was used to verify the agreement.

RESULT

The intraclass correlation coefficients for MUCPs and FULs determined using water-filled and air-charged catheters were 0.89, 0.75, 0.94, and 0.78, respectively. The interclass correlation coefficients for MUCPs and FULs between the two catheters were 0.43 and 0.28, respectively. Bland-Altman plots suggested that the values measured by air-charged catheters were significantly higher than water-filled catheters (mean difference, 26.0 and 2.4 cmH₂ O, respectively). There were wide 95% limits of agreement (-54.0 to 106.0 and -0.3 to 5.1 cmH ₂ O, respectively) that exceeded the clinical range for differences in MUCP and FUL.

CONCLUSION

Air-charged catheters usually give higher readings than water-filled catheters for UPP. Agreement between water-filled and air-charged catheters was not good. Nevertheless, the catheter type which is more relevant to the disease requires further study.