Novel insights into fecal incontinence in men

Global Prevalence of Fecal Incontinence in Community-Dwelling Adults: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Fecal incontinence (FI) can considerably impair quality of life. Through a systematic review and meta-analysis, we sought to determine the global prevalence and geographic distribution of FI and to characterize its relationship with sex and age.

METHODS

We searched PubMed, Web of Science, and Cochrane Library databases to identify population-based surveys of the prevalence of FI.

RESULTS

Of the 5175 articles identified, the final analysis included 80 studies; the median response rate was 66% (interquartile range [IQR], 54%-74%). Among 548,316 individuals, the pooled global prevalence of FI was 8.0% (95% confidence interval [CI], 6.8%-9.2%); by Rome criteria, it was 5.4% (95% CI, 3.1%-7.7%). FI prevalence was greater for persons aged 60 years and older (9.3%; 95% CI, 6.6%-12.0%) compared with younger persons (4.9%; 95% CI, 2.9%-6.9%) (odds ratio [OR], 1.75; 95% CI, 1.39-2.20), and it was more prevalent among women (9.1%; 95% CI, 7.6%-10.6%) than men (7.4%; 95% CI, 6.0%-8.8%]) (OR, 1.17; 95% CI, 1.06-1.28). The prevalence was highest in Australia and Oceania, followed by North America, Asia, and Europe, but prevalence could not be estimated in Africa and the Middle East. The risk of bias was low, moderate, and high for 19 (24%), 46 (57%), and 15 (19%) studies, respectively. Exclusion of studies with high risk of bias did not affect the prevalence of FI or heterogeneity. In the meta-regression, the high study heterogeneity (I2 = 99.61%) was partly explained by age.

CONCLUSIONS

Approximately 1 in 12 adults worldwide have FI. The prevalence is greater among women and older people.

Comparison of etiological and physiological characteristics of fecal incontinence in men and women

Fecal incontinence (FI) is often underreported and underestimated in men. Our aims were to clarify the causes and the physiological characteristics of FI in men and to underline the differences between etiological and physiological factors in men and women diagnosed with FI. The study cohort encompassed 200 men and 200 women who underwent anatomical and physiological evaluation for FI in a tertiary referral center specializing in pelvic floor disorders. All patients underwent endoanal ultrasound and anorectal manometry. Evacuation proctography was performed in some patients. Demographic, medical, anatomical, and physiological parameters were compared between the two study groups. Urge incontinence was the most frequent type of FI in both genders. In men, anal fistula, history of anal surgeries, rectal tumors, and pelvic radiotherapy were common etiologic factors, whereas history of pelvic surgeries was more common in women. Associated urinary incontinence was reported more frequently by women. External anal sphincter defects, usually anterior, were more common in women (M: 1.5%, F: 24%, P < 0.0001), whereas internal anal sphincter defect prevalence was similar in men and women (M: 6%, F: 12%, P = 0.19). Decreased resting and squeeze pressures were less common in men (M: 29%, F: 46%, P < 0.0001: M: 44%, F: 66%, P < 0.0001). The incidence of rectal hyposensitivity was higher in men (M: 11.1%, F: 2.8%, P < 0.0001), whereas rectal hypersensitivity was higher in women (M: 5.8%, F: 10.8%, P < 0.0001). Anorectal dyssynergia was more common in men (M: 66%, F: 37%, P < 0.0001). Significantly different etiological factors and physiological characteristics for FI were found in men. Acknowledging these differences is significant and may yield better treatment options.NEW & NOTEWORTHY Fecal incontinence (FI) in men has different etiological factors when compared with women. The prevalence of internal anal sphincter defect among men with FI was similar to women. Different manometric measurements were found among men with FI: decreased anal pressures were less common among men, whereas rectal hyposensitivity and anorectal dyssynergia were more common among men.

Characteristics of Fecal Incontinence in Male Patients in Japan

OBJECTIVES

Although community studies have shown no difference between the sexes in the prevalence of fecal incontinence (FI), few direct comparisons of disease characteristics between male and female patients have been reported. The aim of this study was to determine whether characteristics of FI differ between male and female patients in Japan.

METHODS

Included in the study were 408 (149 men, 259 women) patients with FI who visited the Matsushima Hospital Coloproctology Center between October 2016 and September 2017. We retrospectively evaluated data on age, number of bowel movements, Bristol stool form scale, number of FI, incontinence scores, anorectal manometry, comorbidities, and history of anal surgery.

RESULTS

Maximum resting pressure and maximum squeeze pressure were found to be within normal range in significantly more male than female patients (34.9% vs. 12.4%, respectively; p < 0.0001). Irritable bowel syndrome (IBS, 20.1% vs. 9.3%; p = 0.003) and a history of anal surgery (29.5% vs. 17.5%; p = 0.02) were more prevalent among male patients than among female patients. Use of mepenzolate as treatment was significantly more common among male patients than among female patients (16.8% vs. 6.6%, respectively; p = 0.005). Responses to the various treatments were good, regardless of sex.

CONCLUSIONS

FI appears to be more commonly accompanied by normal anal sphincter pressures in male patients than in female patients, and IBS and previous anal surgery appear to be more common among male patients than among female patients. FI appears to be controllable in most patients, regardless of sex.

Optimizing techniques for measuring anal resting and squeeze pressures with high-resolution manometry

BACKGROUND

The optimal methods for measuring and analyzing anal resting and squeeze pressure with high-resolution manometry (HRM) are unclear.

METHODS

Anal resting and squeeze pressures were measured with HRM in 90 healthy women, 35 women with defecatory disorders (DD), and 85 with fecal incontinence (FI). Pressures were analyzed with Manoview™ software and a customized approach. Resting pressures measured for 20, 60, and 300 s were compared. During the squeeze period, (3 maneuvers, 20 s each), the squeeze increment, which was averaged over 5, 10, 15, and 20 s, and squeeze duration were evaluated.

RESULTS

Compared to healthy women, the anal resting pressure, squeeze pressure increment, and squeeze duration were lower in FI (p ≤ 0.04) but not in DD. The 20, 60, and 300 s resting pressures were strongly correlated (concordance correlation coefficients = 0.96-0.99) in healthy and DD women. The 5 s squeeze increment was the greatest; 10, 15, and 20 s values were progressively lower (p < 0.001). The squeeze pressure increment and duration differed (p < 0.01) among the three maneuvers in healthy and DD women but not in FI women. The upper 95th percentile limit for squeeze duration was 19.5 s in controls, 19.9 s in DD, and 19.3 s in FI. Adjusted for age, resting pressure, and squeeze duration, a greater squeeze increment was associated with a lower risk of FI versus health (OR, 0.96; 95% CI, 0.94-0.97).

CONCLUSIONS

These findings suggest that anal resting and squeeze pressures can be accurately measured over 20 s. In most patients, one squeeze maneuver is probably sufficient.

Review of the indications, methods, and clinical utility of anorectal manometry and the rectal balloon expulsion test

BACKGROUND

Anorectal manometry (ARM) comprehensively assesses anorectal sensorimotor functions.

PURPOSE

This review examines the indications, techniques, interpretation, strengths, and weaknesses of high-resolution ARM (HR-ARM), 3-dimensional high-resolution anorectal manometry (3D-HR-ARM), and portable ARM, and other assessments (i.e., rectal sensation and rectal balloon expulsion test) that are performed alongside manometry. It is based on a literature search of articles related to ARM in adults. HR-ARM and 3D-HR-ARM are useful for diagnosing defecatory disorders (DD), to identify anorectal sensorimotor dysfunction and guide management in patients with fecal incontinence (FI), constipation, megacolon, and megarectum; and to screen for anorectal structural (e.g., rectal intussusception) abnormalities. The rectal balloon expulsion test is a useful, low-cost, radiation-free, outpatient assessment tool for impaired evacuation that is performed and interpreted in conjunction with ARM. The anorectal function tests should be interpreted with reference to age- and sex-matched normal values, clinical features, and results of other tests. A larger database of technique-specific normal values and newer paradigms of analyzing anorectal pressure profiles will increase the precision and diagnostic utility of HR-ARM for identifying abnormal mechanisms of defecation and continence.

Faecal incontinence in adults

Faecal incontinence, which is defined by the unintentional loss of solid or liquid stool, has a worldwide prevalence of ≤7% in community-dwelling adults and can markedly impair quality of life. Nonetheless, many patients might not volunteer the symptom owing to embarrassment. Bowel disturbances, particularly diarrhoea, anal sphincter trauma (obstetrical injury or previous surgery), rectal urgency and burden of chronic illness are the main risk factors for faecal incontinence; others include neurological disorders, inflammatory bowel disease and pelvic floor anatomical disturbances. Faecal incontinence is classified by its type (urge, passive or combined), aetiology (anorectal disturbance, bowel symptoms or both) and severity, which is derived from the frequency, volume, consistency and nature (urge or passive) of stool leakage. Guided by the clinical features, diagnostic tests and therapies are implemented stepwise. When simple measures (for example, bowel modifiers such as fibre supplements, laxatives and anti-diarrhoeal agents) fail, anorectal manometry and other tests (endoanal imaging, defecography, rectal compliance and sensation, and anal neurophysiological tests) are performed as necessary. Non-surgical options (diet and lifestyle modification, behavioural measures, including biofeedback therapy, pharmacotherapy for constipation or diarrhoea, and anal or vaginal barrier devices) are often effective, especially in patients with mild faecal incontinence. Thereafter, perianal bulking agents, sacral neuromodulation and other surgeries may be considered when necessary.

Is Sacral Nerve Modulation a Good Option for Fecal Incontinence in Men?

OBJECTIVE

The objective was to assess the efficacy and the safety of sacral nerve modulation (SNM) in men with fecal incontinence (FI) compared with those of SNM in women.

METHOD

Prospectively collected data from patients from seven tertiary colorectal units who underwent an implant procedure between January 2010 and December 2015 were reviewed retrospectively. Outcomes and surgical revision and definitive explantation rates were compared between men and women.

RESULTS

A total of 469 patients (60 men [12.8%]; mean age = 61.4 ± 12.0 years) were included in the study, 352 (78.1%) (31 men [8.8%]) of whom received a permanent implant. The ratio of implanted/tested men was significantly lower than the ratio of implanted/tested women (p = 0.0004). After a mean follow-up of 3.4 ± 1.9 years, the cumulative successful treatment rates tended to be less favorable in men than in women (p = 0.0514): 88.6% (75.6-95.1), 75.9% (60.9-86.4), 63.9% (48.0-77.3), and 43.9% (26.7-62.7) at one, two, three, and five years, respectively, in men; 92.0% (89.1-94.2), 84.2% (80.3-87.4), 76.8% (72.3-80.7), and 63.6% (57.5-69.3) at one, two, three, and five years, respectively, in women. The revision rate for infection and the definitive explantation rate for infection were higher in men than in women (p = 0.0001 and p = 0.0024, respectively).

CONCLUSION

Both short- and long-term success rates of SNM for FI were lower in men than in women. The revision and definitive explantation for long-term infection rates were significantly higher in men.

Downregulation of thromboxane A2 and angiotensin II type 1 receptors associated with aging-related decrease in internal anal sphincter tone

Aging-associated decrease in internal anal sphincter (IAS) tone (AADI) is a major contributor in the rectoanal incontinence (RI). To determine the pathogenesis of AADI, we investigated the effect of aging on GPCR activation and related downstream signaling. We particularly investigated two GPCRs that characterize IAS smooth muscle cells (SMCs): thromboxane A2 and angiotensin II type 1. Two groups of Fischer 344 rats (6-month-old [young group] and 26-month-old [old group]) were employed to determine the GPCR function by isometric contraction, the expressions of GPCRs, and their downstream regulatory signaling proteins (regulator of G-protein signaling 2, RGS2; GPCR Kinase 5, GRK5; and β-arrestin, Arrb2) using RT-PCR, qPCR, and western blot analyses. We used reversible biotinylation to monitor the GPCR trafficking using SMCs. Aging selectively attenuated thromboxane A2 and Ang II-induced IAS contraction. RT-PCR, qPCR, and WB data revealed a significant decrease in the expressions of the GPCRs and increase in the expression of RGS2, GRK5, and Arrb2. The increased GPCR internalization and decreased recycling under aging were validated by reversible biotinylation. We conclude that downregulation of GPCR, accompanied by upregulation of regulatory proteins, plays an important role in receptor desensitization and may be important underlying mechanisms of RI in certain aging patients.

In vivo magnetofection: a novel approach for targeted topical delivery of nucleic acids for rectoanal motility disorders

In these studies, we developed a novel approach of in vivo magnetofection for localized delivery of nucleic acids such as micro-RNA-139-5p (miR-139-5p; which is known to target Rho kinase2) to the circular smooth muscle layer of the internal anal sphincter (IAS). The IAS tone is known to play a major role in the rectoanal continence via activation of RhoA-associated kinase (RhoA/ROCK2). These studies established an optimized protocol for efficient gene delivery using an assembly of equal volumes of in vivo PolyMag and miR139-5p or anti-miR-139-5p (100 nM each) injected in the circular smooth muscle layer in the pinpointed areas of the rat perianal region and then incubated for 20 min under magnetic field. Magnetofection efficiency was confirmed and analyzed by confocal microscopy of FITC-tagged siRNA. Using physiological and biochemical approaches, we investigated the effects of miR-139-5p and anti-miR-139-5p on basal intraluminal IAS pressure (IASP), fecal pellet count, IAS tone, agonist-induced contraction, contraction-relaxation kinetics, and RhoA/ROCK2 signaling. Present studies demonstrate that magnetofection-mediated miR-139-5p delivery significantly decreased RhoA/ROCK2, p-MYPT1, and p-MLC₂₀ signaling, leading to decreases in the basal IASP and IAS tone and in rates of contraction and relaxation associated with increase in fecal pellet output. Interestingly, anti-miR-139-5p transfection had opposite effects on these parameters. Collectively, these data demonstrate that magnetofection is a promising novel method of in vivo gene delivery and of nucleotides to the internal anal sphincter for the site-directed and targeted therapy for rectoanal motility disorders. NEW & NOTEWORTHY These studies for the first time demonstrate the success of topical in vivo magnetofection (MF) of nucleic acids using perianal injections. To demonstrate its effectiveness, we used FITC-tagged siRNA via immunofluorescence microcopy and functional and biochemical evidence using miR-139-5p (which is known to target ROCK2). In conclusion, MF allows safe, convenient, efficient, and targeted delivery of oligonucleotides such as siRNAs and microRNAs. These studies have direct therapeutic implications in rectoanal motility disorders especially associated with IAS.