Study of the afferent nervous system and its evaluation in women with impaired detrusor contractility treated with bethanechol

Predictive factors for the success of trial catheter removal for women with urinary retention

OBJECTIVE

To investigate the outcome, determine the predictors for the success of, and evaluate the efficacy of pharmacokinetic therapy on trial catheter removal for women with urinary retention.

METHODS

Inclusion criteria were female patients with acute urinary retention defined as painful, palpable, or percussive bladder, when the patient is unable to pass any urine, accompanied by postvoid residual (PVR) > 250 ml, and who underwent trial catheter removal between July 2009 and July 2019. Before trial catheter removal, alpha-blockers alone or alpha-blockers and parasympathomimetics (bethanechol or distigmine bromide) were used to facilitate spontaneous voiding in some cases.

RESULTS

Fifty-nine of 104 (56.7%) women with urinary retention were catheter-free post trial. There was no significant difference between successful and non-successful trials in average age (p = .392), median ECOG (Eastern Cooperative Oncology Group) performance status (p = .374), diabetes mellitus (p = .842), dementia (p = .801), previous history of cerebrovascular events (p = .592), or intrapelvic surgery (p = .800). Oral medications were administered for 39/59 (66.1%) in the success group and 30/45 (66.7%) patients in the non-success groups (p = .598). Serum albumin (3.2 ± 0.7 g/dl and 2.8 ± 0.8 g/dl, p = .039) and total protein values (6.5 ± 0.8 g/dl and 6.0 ± 1.0 g/dl, p = .038) at diagnosis of urinary retention were higher in the success group than the non-success group, respectively. Multivariate logistic regression found that a serum albumin >3 g/dl was an independent predictor of successful trial catheter removal for women with urinary retention (p = .030, odds ratio [OR] 3.3, 95% confidence interval [CI] of OR 1.1-9.9). Age < 70 years old was a likely predictor of successful trial catheter removal (p = .066, OR 4.8, 95% CI of OR 0.9-25.0).

CONCLUSIONS

This is the first retrospective study to investigate the predictive factors for successful trial catheter removal in women with urinary retention. A serum albumin value >3 mg/dl at diagnosis of urinary retention was a significant independent predictor of catheter-free status after trial catheter removal, and age < 70 years-old was a possible contributor. There was no evidence that oral medication contributed to catheter-free status.

Lower urinary tract electrical sensory assessment: A systematic review and meta-analysis

Objectives

To summarize the current literature on lower urinary tract electrical sensory assessment (LUTESA), with regard to current perception thresholds (CPTs) and sensory evoked potentials (SEPs), and to discuss the applied methods in terms of technical aspects, confounding factors, and potential for lower urinary tract (LUT) diagnostics.

Methods

The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) statement. Medline (PubMed), Embase and Scopus were searched on 13 October 2020. Meta‐analyses were performed and methodological qualities of the included studies were defined by assessing risk of bias (RoB) as well as confounding.

Results

After screening 9925 articles, 80 studies (five randomized controlled trials [RCTs] and 75 non‐RCTs) were included, comprising a total of 3732 patients and 692 healthy subjects (HS). Of these studies, 61 investigated CPTs exclusively and 19 reported on SEPs, with or without corresponding CPTs. The recording of LUTCPTs and SEPs was shown to represent a safe and reliable assessment of LUT afferent nerve function in HS and patients. LUTESA demonstrated significant differences in LUT sensitivity between HS and neurological patients, as well as after interventions such as pelvic surgery or drug treatments. Pooled analyses showed that several stimulation variables (e.g. stimulation frequency, location) as well as patient characteristics might affect the main outcome measures of LUTESA (CPTs, SEP latencies, peak‐to‐peak amplitudes, responder rate). RoB and confounding was high in most studies.

Conclusions

Preliminary data show that CPT and SEP recordings are valuable tools to more objectively assess LUT afferent nerve function. LUTESA complements already established diagnostics such as urodynamics, allowing a more comprehensive patient evaluation. The high RoB and confounding rate was related to inconsistency and inaccuracy in reporting rather than the technique itself. LUTESA standardization and well‐designed RCTs are crucial to implement LUTESA as a clinical assessment tool.

Underactive Bladder and Bladder Outlet Procedures in Women

Purpose of review

This review outlines current options for women suffering from both stress urinary incontinence (SUI) and underactive bladder (UAB). This is often a challenging patient population; however, many treatment options are available including behavioral, pharmacologic, and surgical. Therapies can be divided into those specifically targeting either the bladder or the bladder outlet.

Recent findings

For patients with SUI and UAB, several clinical trials have helped to formulate current guidelines. Also, a number of novel techniques and therapeutic agents are currently under investigation. Current surgical treatments frequently employed for SUI include midurethral slings and urethral bulking agents. In contrast, the current treatments for UAB are limited to either sacral neuromodulation in women with Fowlers syndrome or in the majority, clean intermittent catheterization. Recent studies have investigated the use of adjustable urethral slings and novel modes of neuromodulation with varying degrees of success.

Summary

Choosing the best treatment plan for SUI combined with UAB involves a thorough understanding of a patient's preferences and goals. Fortunately, women have many options that can significantly benefit their quality of life.

Pressure-volume analysis of rat's micturition cycles in vivo

AIMS

Though the pressure-volume analysis (PVA), a method based on thermodynamics, is broadly used for assaying cardiac functions, its potential application on the physiology/pathophysiology of the urinary bladder, which processes resemble thermodynamic cycles to the heart, has not been established.

METHODS

Cystometry recording intravesical pressure (IVP) and intravesical volume (IVV) of rhythmic voiding contractions caused by a constant saline infusion (0.04 mL/min) were carried out in forty urethane-anesthetized female Sprague-Dawley rats, and the PVA was established by plotting IVP against IVV.

RESULTS

Pressure-volume points shaped coincident enclosed loops, and loop-associated urodynamic parameters kept stable under a constant infusion rate (0.04 mL/min). Enhancing preload (by elevating infusion rates to 0.08 and 0.12 mL/min) increased the area enclosed by the loop (Apv) and shifted loops to the right and slightly upward. Augmenting afterload (by enhancing resistances using 1/4 and 1/2 urethra clamping) increased Apv and shifted loops markedly to the right and upward. Without affecting Apv, muscarine (0.01 and 0.1 mM)-induced inotropic states shifted loop to the left and upward that was as opposed to the atropine (0.01 and 0.1 mM)-induced anti-inotropic state.

CONCLUSIONS

Not only consistently assayed baseline bladder functions, PVA but also validly measured modified bladder functions due to altered extrinsic environment and intrinsic contractility of the bladder itself. In accompanied by cystometry, PVA could provide a clear concept about the relationship between time, pressure, and volume in the voiding activity.

Detrusor underactivity in women: A current understanding

AIMS

To examine the current understanding and management of detrusor underactivity (DUA) and underactive bladder (UAB) in women.

METHODS

A review of the current literature was performed with a specific focus on new management strategies and treatment options for women with DUA and UAB.

RESULTS

DUA has become an area of increased interest in recent years. Affecting up to 45% of older women undergoing urodynamic evaluation for non-neurogenic lower urinary tract symptoms, DUA is common. There are a variety of possible etiologies including neurogenic or myogenic dysfunction. As there is currently no cure for DUA and no way to restore the ability of the detrusor muscle to contract, management of DUA in women is mostly focused on effective bladder drainage by urinary catheterization. Clean intermittent catheterization is the gold standard for bladder drainage however for a variety of reasons, women with DUA often are managed with indwelling urethral catheter or suprapubic tube. Medications, sacral neuromodulation, and the inFlow urinary prosthesis are also treatment alternatives or additions to catheterization. Novel therapies using stem cells and gene therapy are also under investigation for the treatment of DUA and UAB.

CONCLUSIONS

DUA is likely more prevalent than recognized and undertreated in women. It is vital that further research in treatment options beyond catheterization be developed for these patients to offer patients a variety of treatment options.

Current pharmacological and surgical treatment of underactive bladder

Generally accepted guidelines are not yet available on the management of underactive bladder (UAB). Although the natural history of UAB is still not fully understood, observation may be an acceptable management option in patients with tolerable lower urinary tract symptoms and little risk of upper urinary tract damage. If needed, scheduled and double voiding may be recommended as an effective and safe add-on therapy. Parasympathomimetics have been widely used for the management of UAB, but the evidence does not support clinical benefit. The efficacy of alpha-blockers has also not yet been clearly demonstrated. However, selective alpha-blockers may help to enhance voiding efficiency and to decrease possible upper tract damage. Sacral neuromodulation is a surgical option for nonobstructive UAB approved by the Food and Drug Administration. However, the response rate of test stimulation is not high and the efficacy of permanent implants does not always coincide with that of test stimulation. Although surgery to reduce outlet resistance may be a viable option in UAB with presumed obstruction, surgery seems to have little role in those without obstruction. Latissimus dorsi detrusor myoplasty has shown promising results in restoring voluntary voiding in selected patients. The procedure requires a multidisciplinary team approach of urologists and plastic reconstructive experts. In summary, current treatments of UAB remain unsatisfactory. The multifactorial nature of UAB pathogenesis complicates the appropriate management for each patient. Future research to establish a more clinically relevant definition of UAB will be required to open new era of UAB management.

Multimodal Vulvar and Peripheral Sensitivity Among Women With Vulvodynia: A Case-Control Study

OBJECTIVE

To assess differences in vulvar and peripheral sensitivity between women with and without vulvodynia.

METHODS

Women with vulvodynia (n = 41) and age-matched controls (n = 43) seen in the outpatient setting were evaluated via surveys, clinical examination, and multimodal sensory testing (pressure, heat, cold, vibration, and electrical stimulation). The relationships between sensitivity to various sensory modalities and case/control status, as well as by vulvodynia subgroups, were assessed using logistic regression.

RESULTS

Women with vulvodynia were more sensitive to pressure and to electrical stimuli than were control women at the vulva (median, 22 vs 230 g and 0.495 vs 0.769 mA, respectively; P < 0.001 for each) and at the thumb (median, 2500 vs 4250 g and 0.578 vs 0.764 mA, respectively; P = 0.006 for pressure, P < 0.001 for electrical stimulation). Heat, cold, and vibration detection thresholds did not differ significantly between these groups (P > 0.025). Those reporting spontaneous pain versus provoked pain had greater pressure sensitivity to the thumb (median, 1850 vs 2690 g; P = 0.020) and greater electrical sensitivity at the introitus (0.450 vs 0.608 mA; P = 0.011), and those with primary versus secondary vulvodynia had substantially greater pressure sensitivity to the thumb (median, 2438 vs 3125 g, P = 0.004). However, having localized versus generalized vulvodynia was not associated with differences in pressure or electrical sensitivity.

CONCLUSIONS

Sensitivities to pressure and electrical stimuli are greater among vulvodynia cases than among controls and support 2 previously defined subgroups-those reporting spontaneous pain versus those whose pain only occurred when provoked, and those with primary versus secondary vulvodynia.

Effects of Silodosin, an α1A-Adrenoceptor Antagonist, and Distigmine, an Acetylcholinesterase Inhibitor, and Their Combined Effects on Impaired Voiding Function in Zucker Diabetic Fatty Rats

BACKGROUND/AIMS

To evaluate the effects of silodosin (α1A-adrenoceptor antagonist) and distigmine (acetylcholinesterase inhibitor), alone or in combination, on voiding dysfunction in Zucker diabetic fatty (ZDF) rats, a type 2 diabetes model, by pressure flow study.

METHODS

Male ZDF rats were anesthetized with urethane and a catheter was implanted into the bladder through the dome. Saline was continuously infused into the bladder at 6 ml/h to induce the micturition reflex. Intravesical pressure and micturition volume were recorded continuously and various urodynamic parameters were calculated using a waveform analysis system.

RESULTS

Increased bladder capacity, residual volume, and urethral resistance and decreased maximum detrusor contraction velocity and urine flow rate, considered to be detrusor underactivity-like symptoms, were observed in ZDF rats. Although both silodosin and distigmine improved impaired voiding function, administration of both drugs in combination was more effective than either drug alone.

CONCLUSIONS

ZDF rats showed symptoms suggestive of detrusor underactivity, and silodosin tended to ameliorate these symptoms in ZDF rats. These results suggested that an α1A-adrenoceptor antagonists may be effective against the voiding disorder accompanying not only bladder outlet obstruction but also deficiency of bladder function. Moreover, combined administration of an α1A-adrenoceptor antagonist with an acetylcholinesterase inhibitor may have additive efficacy in clinical use.

Reproducibility of electrical sensory testing in lower urinary tract at weekly intervals in healthy volunteers and women with non-neurogenic detrusor overactivity

OBJECTIVE

To evaluate the reproducibility of a standardized technique of current perception threshold measurements with square wave and sine wave current, with monopolar and bipolar electrodes in a cohort of patients with overactive bladder (OAB) and healthy volunteers.

METHODS

We enrolled 6 female nulliparous healthy volunteers and 11 female patients with OAB. Current perception threshold measurements of the bladder were performed using several techniques. The same sequence was used for all 3 measurements performed at weekly intervals to assess the reproducibility. An intraclass correlation coefficient >0.75 was considered as very good reproducibility.

RESULTS

All the different stimulation forms were well tolerated by all participants and all experienced stimulation at 2.5-Hz and 95-Hz square wave current. The results with sine wave current showed less uniform results. The intraclass correlation showed the greatest reproducibility with bipolar stimulation at a current of 95 Hz. Sine wave current at 5 Hz and 250 Hz showed low reproducibility. Bipolar stimulation had significantly lower thresholds than monopolar stimulation (P < .0001). No significant differences were found between the healthy subjects and the patients with OAB for the 4 settings.

CONCLUSION

In the healthy volunteers and patients with OAB, the determination of the current perception threshold in the bladder using a standardized method is feasible and well tolerated, with both bipolar and monopolar stimulation. In our study, square wave current showed strong reproducibility at weekly intervals at 2.5 Hz and 95 Hz. However, sinusoid current gave weak reproducibility.

Antimuscarinic effects on current perception threshold: a prospective placebo control study

AIMS

To evaluate the effect of Tolterodine on urethral and bladder afferent nerves in women with detrusor overactivity (DO) in comparison to placebo, by studying the changes in the current perception threshold (CPT).

METHODS

Women with overactive bladder symptoms and idiopathic DO were recruited and randomized in a double-blind manner between placebo and tolterodine extended release. All women underwent CPT testing of the bladder and urethra using a Neurometer constant current stimulator. CPT values were determined at three frequencies, including 2,000 Hz (corresponding to Aβ-fibers), 250 Hz (corresponding to Aδ-fibers), and 5 Hz (corresponding to C fibers) before and 7 days on treatment. CPT values before and on treatment were compared using a Wilcoxon Signed Rank test.

RESULTS

Twenty women (mean age 46 years) were studied. There was no statistical difference between the two groups in terms of age, ethnicity, severity of symptoms and pre-treatment CPT values. Only in the tolterodine group there was a significantly increased CPT value at 5 and 250 Hz upon both urethral and bladder stimulation after 1 week of treatment. When compared with placebo, women taking tolterodine had significantly increased Bladder CPT values at 5 Hz (P-value <0.05). The electrical stimulation with 5 Hz was described as urgency.

CONCLUSIONS

This is a randomized placebo control study evaluating the effect of antimuscarinics on sensory nerve function in women with DO. Our results support the animal studies that antimuscarinics have an effect on sensory function.

Muscarinic acetylcholine receptors in the urinary tract

Muscarinic receptors comprise five cloned subtypes, encoded by five distinct genes, which correspond to pharmacologically defined receptors (M(1)-M(5)). They belong to the family of G-protein-coupled receptors and couple differentially to the G-proteins. Preferentially, the inhibitory muscarinic M(2) and M(4) receptors couple to G(i/o), whereas the excitatory muscarinic M(1), M(3), and M(5) receptors preferentially couple to G(q/11). In general, muscarinic M(1), M(3), and M(5) receptors increase intracellular calcium by mobilizing phosphoinositides that generate inositol 1,4,5-trisphosphate (InsP3) and 1,2-diacylglycerol (DAG), whereas M(2) and M(4) receptors are negatively coupled to adenylyl cyclase. Muscarinic receptors are distributed to all parts of the lower urinary tract. The clinical use of antimuscarinic drugs in the treatment of detrusor overactivity and the overactive bladder syndrome has focused interest on the muscarinic receptors not only of the detrusor, but also of other components of the bladder wall, and these have been widely studied. However, the muscarinic receptors in the urethra, prostate, and ureter, and the effects they mediate in the normal state and in different urinary tract pathologies, have so far not been well characterized. In this review, the expression of and the functional effects mediated by muscarinic receptors in the bladder, urethra, prostate, and ureters, under normal conditions and in different pathologies, are discussed.

[Functional results after temporary continuous drainage of the hypocontractile bladder. The potential rehabilitation of the detrusor]

BACKGROUND

Impaired bladder emptying is a common problem in older people and a challenging task in treatment. Conservative and medical treatment options have shown beneficial effects on micturition; however, in a substantial number of patients the effectiveness of these therapies is disappointing. In the end the decompensated bladder needs indwelling catheterisation. To study the effects on the detrusor function, we analysed the urodynamic data of 31 patients during long-term bladder drainage retrospectively.

PATIENTS AND METHODS

All 17 female and 14 male patients showed impaired detrusor contractility, enlarged bladder capacity, decreased sensitivity and a high post-void residual urine volume (PVR). After exclusion of an acute pathology, the patients were treated continuously with a suprapubic catheter for an average of 13.1 weeks. By urodynamic measurements before and after the drainage period, we analysed the filling parameters, pressure-flow patterns, PVR and detrusor contractility.

RESULTS

At the end of the drainage period, significant changes in the detrusor function were obvious. Compared with the pre-treatment situation, the bladder volume at first desire to void decreased from 306.92 ml to 281.7 ml and the maximum bladder capacity from 691.8 ml to 496.8 ml, respectively. The compliance of the detrusor muscle diminished in the same period of time from 65.6 ml/cmH2O to 51.8 ml/cmH2O. The PVR dropped by 227.2 ml in average. The maximum flow rate was 9.4 ml/s, and the maximum detrusor pressure increased slightly up to 23.6 cmH2O.

CONCLUSION

The continuous drainage of the bladder results in significant changes in the motoric as well as sensoric detrusor function. The reduced bladder capacity and the decreased PVR might be indications of a regenerating process of the detrusor. The long-term drainage of the bladder shows beneficial and therefore therapeutic effects. It still remains to be investigated on a functional as well as structural basis to what extent age, gender and pathogenesis influences the rehabilitation of the detrusor.

The effects of tolterodine on bladder-filling sensations and perception thresholds to intravesical electrical stimulation: method and initial results

OBJECTIVES

To study the effects of the antimuscarinic agent tolterodine on the perception thresholds to intravesical electrical stimulation (IES) and the effects of the drug on subjective bladder sensation during normal filling cystometry in healthy female volunteers.

SUBJECTS AND METHODS

In seven healthy women IES was applied at 2.5 Hz (pulse width 10 ms, protocol 1), 2.5 Hz (pulse width 0.2 ms, protocol 2), and 250 Hz (pulse width 0.2 ms, protocol 3). Sensory perception thresholds were obtained using electric currents in 0.5 mA steps. Afterwards the bladder was filled and the first bladder-filling sensation, first desire to void, strong desire to void and urge to void were recorded. The bladder was then emptied, the volume measured and subjects were checked for residual urine by ultrasonography. The subjects then received 4 mg of tolterodine and the entire protocol was repeated 2 h afterward. The perception thresholds for IES and bladder sensation levels obtained at baseline were compared statistically with the corresponding values after tolterodine.

RESULTS

Tolterodine significantly increased perception thresholds to IES for all three protocols (P = 0.027, 0.018 and 0.018, respectively). The drug had no effect on the filling levels for the corresponding bladder sensation.

CONCLUSION

Oral tolterodine significantly increased the perception threshold to IES in healthy women; there was no effect on subjective bladder sensations during cystometry.

Natural history of detrusor contractility--minimum ten-year urodynamic follow-up in men with bladder outlet obstruction and those with detrusor

OBJECTIVE

To check the long-term effect, in male patients, of treated and untreated bladder outlet obstruction (BOO) on detrusor contractility and to explore the relationship between ageing and detrusor underactivity (DUA).

MATERIAL AND METHODS

Men investigated at the urodynamic department of Southmead Hospital in Bristol between 1972 and 1986 were traced and three groups were invited for repeat pressure-flow urodynamic studies (PFS). The first two groups included patients over 40 years old, with untreated or surgically treated BOO, and the third group had patients with DUA from all age groups.

RESULTS

196 patients (with a minimum 10 year gap from the first assessment) agreed to have repeat PFS. There was no statistically significant change in bladder contractility index (BCI) in patients with BOO treated by transurethral resection of the prostate (TURP) (mean difference in BCI was 0.01, 95% confidence interval -0.07 to 0.09, n=114). There was also no significant difference in BCI in untreated patients with BOO (p=0.10, n=53). The follow-up BCI was higher in untreated patients than in the surgically treated group. The BCI in patients with DUA did not change significantly after a minimum of 10 years' follow-up.

CONCLUSIONS

There is no evidence to suggest that detrusor contractility declines with long-term BOO. Relieving the obstruction surgically does not improve the contractility. This is important when considering and counselling for TURP. Underactive detrusors remain underactive, but do not get worse with time, which could indicate that this is not an ageing process per se and may even have a congenital basis.

Effects of TAK-802, a novel acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their synergistic effects on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction

OBJECTIVE

To investigate the effects of TAK-802, a potent acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their concomitant administration on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction.

MATERIALS AND METHODS

Cystometry was performed in urethane-anaesthetized guinea pigs, and various urodynamic variables, including the maximum flow rate (Qmax), voiding efficiency, maximum intravesical pressure (Pvesmax) and intravesical pressure at Qmax (PvesQmax), were measured before and after administration of the drugs in combination and alone.

RESULTS

Continuous intravenous infusion of phenylephrine, an alpha1-adrenoceptor agonist (1-6 microg/animal/min), dose-dependently decreased the Qmax and voiding efficiency, and increased the Pvesmax and PvesQmax, possibly by constricting urethral smooth muscle. In this functional urethral constriction model, both TAK-802 at 1 and 10 microg/kg and tamsulosin at 3 and 10 microg/kg (intravenously) caused increasing effects on the Qmax and voiding efficiency. The effects were more apparent with combined exposure. Although the Pvesmax was dose-dependently increased by TAK-802 alone, the effects were completely abolished by concomitant treatment with tamsulosin.

CONCLUSION

These results suggest that TAK-802 and tamsulosin have synergistic effects in increasing the Qmax and voiding efficiency, and TAK-802 does not inhibit the decreasing effect of tamsulosin on urethral resistance. That TAK-802 increased Pves when administered alone implies that monotherapy using an acetylcholinesterase inhibitor should be withheld in patients with voiding dysfunction caused by obvious bladder outlet obstruction with benign prostatic hyperplasia, to avoid disorders of the upper urinary tracts, and it should be used with an alpha1-adrenoceptor antagonist. Whether TAK-802 combined with an alpha1-adrenoceptor antagonist confers additional clinical benefit is not yet known.

Current perception thresholds in the lower urinary tract: Sine- and square-wave currents studied in young healthy volunteers

AIMS

To establish normative current perception threshold (CPT) values with neuroselective sine-wave current in the lower urinary tract and to compare these values with square-wave current CPTs.

MATERIALS AND METHODS

10 female and 8 male healthy volunteers were used for this study. A filling cystometry was performed and CPTs were determined with square-wave current at a frequency of 2.5 Hz and with neuroselective sine-wave current at 5 (C-fiber), 250 (Adelta-fiber), and 2000 Hz (Abeta-fiber) in the bladder, the posterior, and the distal urethra.

RESULTS

Bladder CPTs were significantly higher compared with CPTs in the posterior urethra (P < 0.028) and in the distal urethra (P < 0.002) with all three sine-wave frequencies. No significant difference was found with any sine-wave frequency between the posterior and distal urethra (P > 0.30). Using square-wave pulses at 2.5 Hz, CPTs decreased towards the distal urethra, with a significant difference between the three stimulation sites (P < 0.0001). At all sites tested, the CPT's determined with sine-wave current at 2000 Hz were significantly higher than those at 250 Hz (P < 0.002) and 5 Hz (P < 0.001). No significant difference was found between 5 Hz and 250 Hz at any site in the LUT (P > 0.50). At all sites, CPTs determined with square-wave pulses at 2.5 Hz were significantly higher than those determined with sine-wave current at all frequencies (P < 0.001). CPTs determined with all sine-wave currents were not correlated with CPTs using square-wave pulses. There was no correlation between the volumes at which sensation of filling occurred and the CPTs.

CONCLUSIONS

We described normative values in young healthy volunteers at three sites in the LUT using sine-wave current. Although this type of current is said to be neuroselctive, this needs to be confirmed. Stimulation with sine-wave current is different and might be more physiologic compared to square-wave stimulation. Our data show that sine-wave current stimulation at 5 Hz, 250 Hz, and 2000 Hz can probably not be used as a semi-objective measurement of the sensation of bladder filling because no correlation was found between CPTs and the cystometeric sensation of filling.

The basics behind bladder pain: A review of data on lower urinary tract sensations

Interstitial cystitis is a syndrome consisting of frequency, urgency, and bladder pain that increases with bladder filling and improves temporarily after voiding. The exact cause or causes are not as yet fully understood. This leads to uncertainty in diagnosis and treatment. There is need for more knowledge, and to acquire this for more research. The fact that the condition causes pain, a pathologic stimulation of sensory fibres, makes understanding the basic sensory mechanisms in the lower urinary tract in normal and pathologic conditions mandatory. In this article we review the data on bladder sensation from the last 25 years and the possible relation with painful bladder syndrome.