Understanding underactive bladder: a review of the contemporary literature

Exploring the lived experience of Arab male patients on intermittent catheterization after spinal cord injury: A phenomenological study

BACKGROUND

Intermittent catheterization (IC) has been identified as one of the critical techniques used by spinal cord injury (SCI) patients to cope with emptying the bladder, despite several problems impeding this procedure.

AIM

The study aimed accordingly to explore the lived experience of Arab male patients on IC after their SCI.

DESIGN

This study was carried out by using a descriptive qualitative approach with a phenomenological analysis of data.

METHODS

A qualitative study was carried out on 10 Arab male patients from the Rehabilitation Hospital at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia who were utilizing intermittent catheters following SCI. The interviews were analysed using Husserl's phenomenology and the Colaizzi method of data analysis.

RESULTS

Two major themes and six sub-themes were identified from exploring the patients experience. These themes are as follows: Theme 1: The Way to IC; with two sub-themes: (i) 'service provided and acceptance' and (ii) 'educational experience'; Theme 2: Lifestyle and self-adaptation; with four sub-themes: (i) 'Flexibility and freedom', (ii) 'Physical access to the community', (iii) 'Traveling' and (iv) 'Work and Social life balance'.

CONCLUSION

It is evident that using an intermittent catheter among patients with SCI influenced almost all aspects of the participant's life, including their social lives and body image appearance.

Summary Paper on Underactive Bladder from the European Association of Urology Guidelines on Non-neurogenic Male Lower Urinary Tract Symptoms

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU) Guidelines Panel on non-neurogenic male lower urinary tract symptoms (LUTS) aimed to develop a new subchapter on underactive bladder (UAB) in non-neurogenic men to inform health care providers of current best evidence and practice. Here, we present a summary of the UAB subchapter that is incorporated into the 2024 version of the EAU guidelines on non-neurogenic male LUTS.

METHODS

A systematic literature search was conducted from 2002 to 2022, and articles with the highest certainty evidence were selected. A strength rating has been provided for each recommendation according to the EAU Guideline Office methodology.

KEY FINDINGS AND LIMITATIONS

Detrusor underactivity (DU) is a urodynamic diagnosis defined as a contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or failure to achieve complete bladder emptying within a normal time span. UAB is a terminology that should be reserved for describing symptoms and clinical features related to DU. Invasive urodynamics is the only widely accepted method for diagnosing DU. In patients with persistently elevated postvoid residual (ie, >300 ml), intermittent catheterization is indicated and preferred to indwelling catheters. Alpha-adrenergic blockers are recommended before more invasive techniques, but the level of evidence is low. In men with DU and concomitant benign prostatic obstruction (BPO), benign prostatic surgery should be considered only after appropriate counseling. In men with DU and no BPO, a test phase of sacral neuromodulation may be considered.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The current text represents a summary of the new subchapter on UAB. For more detailed information, refer to the full-text version available on the EAU website (https://uroweb.org/guidelines/management-of-non-neurogenic-male-luts).

PATIENT SUMMARY

The European Association of Urology guidelines on underactive bladder in non-neurogenic adult men are presented here. Patients must be fully informed of all relevant options and, together with their treating physicians, decide on the most optimal management for them.

Underactive Bladder and Detrusor Underactivity: New Advances and Prospectives

Underactive bladder (UAB) is a prevalent but under-researched lower urinary tract symptom that typically occurs alongside detrusor underactivity (DU). Unlike UAB, DU is a urodynamic diagnosis which the International Continence Society (ICS) defines as "a contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or a failure to achieve complete bladder emptying within a normal time span". Despite the widespread prevalence of UAB/DU, there are significant gaps in our understanding of its pathophysiological mechanisms, diagnosis, and treatment compared with overactive bladder (OAB) and detrusor overactivity (DO). These gaps are such that clinicians regard UAB/DU as an incurable condition. In recent years, the understanding of UAB has increased. The definition of UAB has been clarified, and the diagnostic criteria for DU have been considered more comprehensively. Meanwhile, a number of non-invasive diagnostic methods have also been reported. Clinical trials involving novel drugs, electrical stimulation, and stem cell therapy have shown promising results. Therefore, this review summarizes recent reports on UAB and DU and highlights the latest advances in their diagnosis and treatment.

The Efficacy of Transvaginal Ultrasound-Guided BoNT-A External Sphincter Injection in Female Patients with Underactive Bladder

Owing to the diverse treatment outcomes after a botulinum toxin A (BoNT-A) injection to the external sphincter, this study aimed to develop a new technique: an ultrasound-guided BoNT-A external sphincter injection. This single-center prospective cohort study was conducted at a tertiary medical center in Taichung, Taiwan. From December 2020 to September 2022, 12 women were enrolled. The patients were evaluated for lower urinary tract syndrome using patient perception of bladder condition (PPBC), international prostate symptom score (IPSS), uroflowmetry, post-void residual volume (PVR), cystometry, and external sphincter electromyography. We evaluated the patients the day before surgery and 1 week after the BoNT-A injection. For the patients requiring self-catheterization, we recorded the number of times they required clean intermittent catheterization (CIC) per day before the procedure and 1 month after the procedure. The IPSS, PPBC, and PVR were significantly better after the transvaginal ultrasound-guided BoNT-A external sphincter injection. The number of times the patients required daily CIC was also reduced after the injection. Only one patient developed de novo urge urinary incontinence. Our results demonstrated that a transvaginal ultrasound-guided BoNT-A injection was efficacious and safe in the treatment of underactive bladder.

HucMSC exosomes attenuate partial bladder outlet obstruction-induced renal injury and cell proliferation via the Wnt/β-catenin pathway

Bladder outlet obstruction (BOO) can cause serious complications including kidney damage; nevertheless, there are currently no animal models for studying BOO-induced kidney damage. Mesenchymal stem cells (MSCs) are widely used in therapeutic studies of renal fibrosis. However, MSC-derived exosomes show improved safety profile and more controllable characteristics compared with those of MSCs. Herein, we established a kidney injury mouse model of partial bladder outlet obstruction (PBOO) and evaluated the effects of human umbilical cord MSC-derived exosomes (hucMSC-Exos) on PBOO-induced reflux kidney injury in this model. Exosomes were isolated from a hucMSC-conditioned medium, purified by ultracentrifugation, and examined. Living image was performed to indicate the distribution of hucMSC-Exos. The PBOO-treated mice interacted with PBS (phosphate-buffered saline) or hucMSC-Exos. Morphologic changes and expression of interstitial-fibrosis-related, cell proliferation and Wnt/β-catenin signaling-pathway indices were evaluated. At 7 days after induction of PBOO, structural destruction of renal tubules was observed. Expression of the interstitial markers and the cellular-proliferation index increased significantly in the PBOO group compared with the control group (p < 0.05). The isolated exosomes were 30-150 nm in diameter, showing a round shape and bilayer membrane structure with CD63, TSG101, Alix expressed, enriched in the kidney of the PBOO group. Administering hucMSC-Exos to post-PBOO mice reversed renal injury and suppressed expression of Wnt/β-catenin signaling pathway-related proteins. hucMSC-Exos inhibited PBOO-induced kidney injury and cellular proliferation and suppressed the Wnt/β-catenin signaling pathway. Our findings will spur the development of novel hucMSC-Exo-mediated therapies for treating patients with renal fibrosis.

Myogenic Underactive Bladder and Heart Failure Resemblance: A Novel Role for SGLT2 Inhibition?

The heart and bladder share physiological biomechanical determinants of contraction. Heart failure (HF) and myogenic underactive bladder (mUAB) also share similarities in their pathophysiology. In both cases there is muscle injury that is directly linked to disease stage. In the final stage, both myocardium and detrusor show marked fibrosis and lower contractility. While HF has an established pharmacological treatment, there are still no effective drugs for mUAB. This mini-review explores the similarities between HF and mUAB and suggests that, as in HF, SGLT2 inhibitors may also have a beneficial role in mUAB. PATIENT SUMMARY: To date, there is no treatment for underactive bladder caused by problems with the bladder muscle (mUAB). We review similarities between this condition and heart failure and hypothesize that a recent drug class with striking results in heart failure might also have a beneficial role in mUAB.

Advances in Assistive Electronic Device Solutions for Urology

Recent technology advances have led urology to become one of the leading specialities to utilise novel electronic systems to manage urological ailments. Contemporary bladder management strategies such as urinary catheters can provide a solution but leave the user mentally and physically debilitated. The unique properties of modern electronic devices, i.e., flexibility, stretchability, and biocompatibility, have allowed a plethora of new technologies to emerge. Many novel electronic device solutions in urology have been developed for treating impaired bladder disorders. These disorders include overactive bladder (OAB), underactive bladder (UAB) and other-urinary-affecting disorders (OUAD). This paper reviews common causes and conservative treatment strategies for OAB, UAB and OUAD, discussing the challenges and drawbacks of such treatments. Subsequently, this paper gives insight into clinically approved and research-based electronic advances in urology. Advances in this area cover bladder-stimulation and -monitoring devices, robot-assistive surgery, and bladder and sphincter prosthesis. This study aims to introduce the latest advances in electronic solutions for urology, comparing their advantages and disadvantages, and concluding with open problems for future urological device solutions.

Effects of losartan on bladder dysfunction due to aging-related severe hypertension in rats

Aging is a major risk factor for bladder dysfunction. Anti-hypertensive drugs, angiotensin II type 1 receptor blockers (ARBs), are reported to ameliorate lower urinary tract dysfunction in rodent models and humans. We aimed to examine the preventive effect of an ARB, losartan, against bladder dysfunction due to aging-related severe hypertension. Male spontaneously hypertensive rats (SHRs) (36-week-old) were administered losartan (0, 3, or 10 mg/kg, p.o.) for 18 weeks. Age-matched, vehicle-treated Wistar Kyoto rats (WKYs) were used as controls. After the treatments, bladder and renal weight, mean blood pressure, and voiding parameters were measured. Additionally, detrusor thickness and bladder arterial wall thickness were evaluated using hematoxylin and eosin staining. Renal morphology was also assessed using periodic acid-Schiff staining. Compared to WKYs, SHRs demonstrated significantly higher bladder weight/body weight ratio (BBR), renal weight/body weight ratio, mean blood pressure, detrusor thickness, bladder arterial wall thickness, urine output, water intake, post-voiding residual urine volume, bladder capacity, intercontraction interval, and rate of glomerular and tubular injury and a lower urine osmolality. A low dose of losartan decreased the urine output, post-voiding residual urine volume, and bladder capacity in SHRs but not mean blood pressure in SHRs. A high dose of losartan decreased the BBR, mean blood pressure, detrusor thickness, bladder arterial wall thickness, post-voiding residual urine volume, bladder capacity, intercontraction interval, and glomerular and tubular injury in SHRs. Losartan inhibits bladder dysfunction in aged SHRs. The ARB losartan might be a preventive drug for bladder dysfunction due to aging-related severe hypertension.

Sacral neuromodulation in patients with detrusor underactivity: Is biological sex an indicator?

OBJECTIVES

This study aimed to report sacral neuromodulation (SNM) outcomes in detrusor underactivity (DU).

METHODS

A multicentric, multinational, retrospective case series was conducted between March 2017 and June 2021 in three different referral centers. Initial test phase stimulation included either a percutaneous nerve evaluation (PNE) or an advanced lead evaluation test phase (ALTP) before permanent SNM implantation. The test phases were performed under local anesthesia, either in the outpatient (PNE) or operating room (ALTP), in the prone position, which was implanted in the third or fourth sacral foramina under fluoroscopic guidance. Patients with favorable response to the initial test phase during the first 2 weeks underwent the implantable pulse generator (IPG) implantation (Medtronic neurostimulation generator device InterStim™). Favorable response was defined as ≥ 50% improvement in symptoms, frequency of clean intermittent catheterization (CIC) and/or decrease in postvoid residual (PVR), increase in voided volume, or improvement in bladder voiding efficiency (BVE) based on the bladder diary.

RESULTS

Fifty-eight patients were recruited with a mean age of 39.95 ± 15.28 years. Among the 58 cases, 36 (62.1%) patients responded to the initial stage. Of these, 12 patients (30.8%) with non-neurogenic etiology and nine patients (52.9%) with neurologic etiology did not respond to the initial test phase; thus, they did not undergo full implantation (p = 0.141). Voided volume, PVR, and the median maximum flow rate (Qmax) improved significantly (p < 0.001) in both sexes; however, there was no statistical difference between both genders. Most female cases (78.3%), and nearly half of the men (51.4%), responded to the test phase and were candidates for the IPG phase. Among the 35 cases who underwent IPG, 27 patients (72.2% of males, and 77.8% of females; p = 0.700) had a favorable response to IPG. 46.6% of patients had a successful outcome at the end of the study.

CONCLUSION

This multicentric study showed that SNM effectively and safely provided symptom improvement in refractory DU in males similar to females which is an important finding as previously it has been suggested that SNM works better in nonobstructive urinary retention in women and not in women.

[Establishment of an Animal Model of Vesicoureteral Reflux Renal Injury through Partial Bladder Outlet Obstruction]

OBJECTIVE

To establish an animal model of reflux renal damage through bladder outlet obstruction.

METHODS

Sixty male C57BL/6 mice aged 6-8 weeks were randomly assigned to a control group, a sham operation group, and a partial bladder outlet obstruction (PBOO) group, with 20 mice in each group. Laparotomy were performed on the PBOO mice under anesthesia in order to separate the bladder necks and to perform guided partial ligation of the bladder neck with a metal rod of 0.3 mm diameter. Mice in the sham operation group had laparotomy and had their bladder necks separated without ligation. The control group did not receive any treatment. 7 days after the surgery, 12 surviving mice were randomly selected from each group to observe the general changes of the bladder, ureter, renal pelvis and kidney. Retrograde urography was performed through the bladder. Kidney tissues were extracted for histopathological analysis. The expression levels of Vimentin, proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were examined with Western blot, immunohistochemistry and immunofluorescence staining tests, respectively.

RESULTS

Compared with the control and sham operation group, the bladder, ureter, and renal pelvis of the mice in the PBOO group were significantly enlarged, vesicoureteral reflux was more obvious, the kidney volume and mass increased ( P<0.001), and renal parenchyma became thinner ( P<0.000 1). Histopathological staining showed glomerular atrophy, renal tubule expansion, tubulointerstitial inflammatory cell infiltration, glomerular basement membrane hyperplasia and obvious interstitial fibrosis. Western blot, immunofluorescence and immunohistochemistry staining showed that the expression levels of Vimentin, PCNA and α-SMA in kidney tissue were elevated ( P<0.000 1).

CONCLUSION

After PBOO, the bladder, ureter, and kidney of the mice showed obvious morphological alteration and presented reflux renal fibrosis-like damage. This can be used as an animal model to study the pathological alteration mechanism and therapeutic measures of renal fibrosis caused by bladder outlet obstruction.

Irreversible Bladder Remodeling Induced by Fibrosis

Underactive bladder and impaired bladder compliance are irreversible problems associated with bladder fibrosis. Remodeling of the extracellular matrix is regarded as an important mechanism associated with bladder fibrosis. However, various risk factors and conditions contribute to the functional impairment of the bladder associated with fibrosis, and there is limited knowledge about bladder fibrosis-associated problems in the field of neurourology. Further studies are thus necessary to elucidate the underlying mechanism of bladder fibrosis and to identify effective treatment.