Continent women have better urethral neuromuscular function than those with stress incontinence

How Does the Urethra Respond to Bladder Filling in Continent and Incontinent Women?

OBJECTIVE

The objective of this study was to describe mean urethral pressure (MUP) during filling cystometry in continent and incontinent women.

METHODS

Incontinent women were recruited from a urogynecology clinic if they answered "sometimes" or "always" to 1 of the items on the Medical, Epidemiologic, and Social Aspects of Aging questionnaire. Participants were categorized by Medical, Epidemiologic, and Social Aspects of Aging scores into stress urinary incontinence (SUI) or urgency urinary incontinence (UUI) groups. Continent women were recruited from the community. Multichannel urodynamics were performed using microtip catheters. Urethral pressure profiles were obtained with an empty bladder and at 100-mL increments during filling. Data were analyzed in SPSS. Continuous variables were compared with independent t test or analysis of variance, categorical variables with the χ2 test, and multivariable comparisons were made with linear regression.

RESULTS

Eighty-six women (30 continent, 56 incontinent: 37 SUI, 19 UUI) with a mean ± SD age of 48 ± 15 years and a body mass index (BMI) of 31 ± 9 participated. Sixty-nine percent were White, 43% were postmenopausal, and 80% were parous. Continent women were younger (P < 0.001) and had a lower BMI (P = 0.004). Mean cystometric capacity was higher in women with SUI and continent women than in women with UUI (430 ± 142, 448 ± 101, and 332 ± 160, P = 0.04). Continent women had higher MUP at baseline when controlling for age, BMI, and parity (84 ± 35 cmH2O vs 62 ± 28 cmH2O; aR2 = 0.2, P = 0.02) compared with incontinent women. During filling, MUP in continent women was 20-30 cmH2O higher at all bladder volumes than incontinent women. Mean urethral pressure increased significantly between baseline and 300 mL in continent women (P < 0.005) and women with SUI (P = 0.04), but not in women with UUI (P = 0.48).

CONCLUSIONS

Continent women have greater baseline MUP and greater increases in MUP during bladder filling than incontinent women.

Neuromuscular urethral function and urethral urodynamic parameters between urgency and stress incontinence do not differ

INTRODUCTION AND HYPOTHESIS

To describe and compare urethral neuromuscular function using concentric needle electromyography (CNEMG) and urodynamic (UDS) parameters between stress incontinent (SUI) and urge incontinent (UUI) women.

METHODS

Incontinent women were recruited from a urogynecology clinic if they answered "sometimes" or "always" to one of the items on the Medical, Epidemiologic, and Social Aspects of Aging questionnaire. Participants were categorized by MESA scores into stress (SUI) or urgency (UUI) incontinence groups. Participants underwent CNEMG of the striated urethral sphincter at three insertion sites using Medtronic multiple motor unit action potential analysis. UDS was performed with Laborie microtip catheters: urethral pressure profiles were obtained at baseline and 300 ml. Data were analyzed in SPSS. Continuous variables were compared with independent t-test or Mann-Whitney U, categorical variables with chi-square test. A logistic regression was performed to control for variables found to be significant on univariate analysis.

RESULTS

Fifty-six women (37 SUI, 19 UUI) with mean ± SD age of 53 ± 13 years participated. At baseline, patients with SUI were younger, more likely to be premenopausal and had lower BMIs. There were no differences in urethral EMG or UDS parameters between UUI and SUI women except lower maximum cystometric capacity in women with UUI. When controlling for age, BMI and MCC on logistic regression, there remained no differences between SUI and UUI groups on EMG or UDS parameters.

CONCLUSIONS

Women with UUI and DO show similar evidence of denervation-reinnervation injury to the striated urethral sphincter muscle as women with SUI.

The pathophysiology of stress urinary incontinence: a systematic review and meta-analysis

Introduction and hypothesis

To evaluate the evidence for pathologies underlying stress urinary incontinence (SUI) in women.

Methods

For the data sources, a structured search of the peer-reviewed literature (English language; 1960–April 2020) was conducted using predefined key terms in PubMed and Embase. Google Scholar was also searched. Peer-reviewed manuscripts that reported on anatomical, physiological or functional differences between females with signs and/or symptoms consistent with SUI and a concurrently recruited control group of continent females without any substantive urogynecological symptoms. Of 4629 publications screened, 84 met the inclusion criteria and were retained, among which 24 were included in meta-analyses.

Results

Selection bias was moderate to high; < 25% of studies controlled for major confounding variables for SUI (e.g., age, BMI and parity). There was a lack of standardization of methods among studies, and several measurement issues were identified. Results were synthesized qualitatively, and, where possible, random-effects meta-analyses were conducted. Deficits in urethral and bladder neck structure and support, neuromuscular and mechanical function of the striated urethral sphincter (SUS) and levator ani muscles all appear to be associated with SUI. Meta-analyses showed that observed bladder neck dilation and lower functional urethral length, bladder neck support and maximum urethral closure pressures are strong characteristic signs of SUI.

Conclusion

The pathology of SUI is multifactorial, with strong evidence pointing to bladder neck and urethral incompetence. While there is also evidence of impaired urethral support and levator ani function, standardized approaches to measurement are needed to generate higher levels of evidence.

Neurophysiologic study in idiopathic overactive bladder

AIM

Idiopathic overactive bladder (OAB) is a prevalent, mystifying disorder with a questionable neurogenic background. We aimed to investigate the possible subtle neuropathic affection underlying its pathogenesis.

METHODS

A cross-sectional cut off study was carried out on a series of 38 females with idiopathic OAB and 22 healthy matched female volunteers. The following was performed: symptom score questionnaire, determination of pudendal nerve terminal motor latency (PNTML), sacral reflexes' latencies, pudendal somatosensory evoked potentials, and needle electromyography of the external anal and urethral sphincters.

RESULTS

A highly significant prolongation of PNTMLs and sacral reflexes latencies among the patients group was detected (P ≥ 0.001). Pudendal somatosensory evoked potentials showed non- significance among the two studied groups (P ≥ 0.05). External anal sphincter neuropathic affection was detected in 27 patients (71%) and external urethral sphincter neuropathic affection was detected in 30 patients (78.9%). The clitoral anal reflex showed the highest sensitivity and specificity among the neurophysiologic tests used in assessing the neuropathic affection (86.7 and 83%, respectively), followed by PNTML (83.3 and 80%, respectively).

CONCLUSION

Pudendal neuropathy is the dominating possible attributing factor in the pathogenesis underlying idiopathic OAB. An integrated clinical, urodynamic, and electro-physiological assessment is recommended for evaluation of any overactive bladder patients.

Anatomy of the pubovisceral muscle origin: Macroscopic and microscopic findings within the injury zone

AIMS

The levator ani muscle (LA) injury associated with vaginal birth occurs in a characteristic site of injury on the inner surface of the pubic bone to the pubovisceral portion of the levator ani muscle's origin. This study investigated the gross and microscopic anatomy of the pubic origin of the LA in this region.

METHODS

Pubic origin of the levator ani muscle was examined in situ then harvested from nine female cadavers (35-98 years). A combination of targeted feature sampling and sequential sampling was used where each specimen was cut sequentially in approximately 5 mm thick slices apart in the area of known LA injury. Histological sections were stained with Masson's trichrome.

RESULTS

The pubovisceral origin is transparent and thin as it attaches tangentially to the pubic periosteum, with its morphology changing from medial to lateral regions. Medially, fibers of the thick muscle belly coalesce toward multiple narrow points of bony attachment for individual fascicles. In the central portion there is an aponeurosis and the distance between muscle and periosteum is wider (∼3 mm) than in the medial region. Laterally, the LA fibers attach to the levator arch where the transition from pubovisceral muscle to the iliococcygeal muscle occurs.

CONCLUSIONS

The morphology of the levator ani origin varies from the medial to lateral margin. The medial origin is a rather direct attachment of the muscle, while lateral origin is made through the levator arch.

How common is pelvic floor muscle atrophy after vaginal childbirth?

OBJECTIVE

To determine if there is evidence of levator ani atrophy in primiparous women.

METHODS

This was a prospective observational cohort study of 202 primiparous women recruited between November 2006 and March 2008. Translabial ultrasound volumes were obtained at 36-38 weeks' gestation and at a mean of 4.5 months postpartum. Peripartum changes in bladder neck elevation and reduction of anteroposterior hiatal diameter on pelvic floor muscle contraction (PFMC) and changes in muscle thickness were analyzed.

RESULTS

Of the 202 participants enrolled, 158 (78%) completed the study. There was a significant reduction in bladder neck elevation (P = 0.001) and change in anteroposterior hiatal diameter (P = 0.03) on PFMC when comparing antenatal and postnatal results, the latter being significantly associated with delivery mode (P = 0.013). No significant changes were detected in muscle thickness (P = 0.76).

CONCLUSIONS

There is a reduction in sonographic measures of pelvic floor function after childbirth, but muscle atrophy is unlikely to be a significant factor.

Urethral sphincter innervation and clitoral blood flow after the transobturator (TOT) approach

INTRODUCTION AND HYPOTHESIS

The aim of the study was to exclude neurovascular damage due to prosthetic mini-invasive surgery using transobturator tape (TOT) by pre- and postoperative electromyography (EMG) of the striated urethral sphincter and a color Doppler ultrasonography evaluation of clitoral blood flow.

METHODS

A total of 25 women affected by clinical stress urinary incontinence (SUI) were enrolled. After undergoing urodynamic assessment, pelvic organ prolapse quantification, urine culture, Q-tip test, and stress test, each subject underwent color Doppler ultrasonography to record clitoral blood flow and EMG of the urethral sphincter with a needle electrode inserted through the mucosa into the muscle tissue before surgery. A single urogynecologist performed the TOT surgical technique for the treatment of all patients. Urogynecologic examination, EMG, and color Doppler ultrasound follow-up were performed at 1 and 6 months after surgery.

RESULTS

At the urogynecologic examination performed 1 and 6 months after the TOT approach the stress test was negative, urethral hypermobility was reduced, and sling exposure was not observed for each patient. There was no statistically significant difference in electromyographic values (p > 0.05) in both the follow-ups with regard to baseline values. Pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV) values increased during the first follow-up (p < 0.01); PI and RI values increased during the second follow-up with respect to baseline values (p < 0.01)

CONCLUSIONS

TOT prosthesis surgery, avoiding denervation and devascularization of pelvic structures, does not damage the urethral sphincter.

Complex repetitive discharges--a feature of the urethral continence mechanism or a pathological finding?

PURPOSE

We compared the proportion of women with complex repetitive discharges on urethral sphincter electromyography during filling cystometry among women with and without urinary disorders.

MATERIALS AND METHODS

After receiving institutional review board approval we recruited community dwelling women without urinary symptoms and women who presented for urinary incontinence treatment. Participants completed the Pelvic Floor Distress Inventory. Women who responded affirmatively to an inventory item ("Do you have difficulty emptying your bladder?" or "Do you experience a feeling of incomplete bladder emptying?") were classified with voiding dysfunction. Women with post-void residual urine greater than 100 ml, active urinary tract infection, prolapse greater than stage II or neuromuscular disease were excluded from study. Participants underwent standardized multichannel urodynamics with continuous concentric needle electromyography of the urethral sphincter throughout filling cystometry.

RESULTS

In the 31 controls and 56 incontinent participants mean±SD age was 48±15 years and median vaginal parity was 1 (range 0 to 2). The urodynamic diagnosis in the incontinent group included urodynamic stress incontinence in 31 (56%), detrusor overactivity with incontinence in 17 (30%) and mixed urodynamic stress incontinence with detrusor overactivity in 8 (14%). Of the women 26 (32%) met voiding dysfunction criteria with 96% reporting a feeling of incomplete bladder emptying and 53% reporting difficult bladder emptying. Controls were significantly more likely to have complex repetitive discharges than incontinent women (9 of 30 vs 2 of 56, p<0.002).

CONCLUSIONS

Complex repetitive discharges occur in about a third of women without urinary symptoms.