Relationship between desire to void and bladder capacity and rectal sensory function in patients with multiple sclerosis and anorectal disorders.

AIMS: The primary aim of this study was to assess the relationship between a strong desire to void (SDV) and rectal sensory function in patients with multiple sclerosis (PwMS) and anorectal disorders. The secondary aim was to identify clinical, urodynamic or manometric factors associated with greater rectal sensory function impairment in this population. METHODS: Thirty PwMS (mean age 49.2 ± 10.9 years) with anorectal disorders (constipation and/or fecal incontinence) participated in this observational study. Rectal sensory parameters during anorectal manometry were recorded at a strong desire to void and after urination (PV, post-void). The primary outcome was the desire to defecate volume. Secondary outcomes were first perception and maximum tolerated threshold volumes, presence and modulation of recto-anal inhibitory reflex. RESULTS: The mean desire to defecate volume was 125 ± 59 mL at SDV and 104 ± 64 mL at PV (P < .001). The mean maximum tolerated volume was 167 ± 61 mL at SDV vs 141 ± 64 mL after urination (P = .01). The other parameters were not different between SVD and PV conditions. No predictive factors for greater impairment of rectal sensory function were identified. CONCLUSION: This study suggests a relationship between bladder sensation and thus bladder capacity, and rectal sensory function in PwMS and with anorectal disorders.

Fecal Urgency: Clinical and Manometric Characteristics in Patients With and Without Diarrhea.

BACKGROUND: Fecal urgency is classically associated with diarrhea, but is also common in individuals with normal bowel habits or constipation. Its etiology, particularly in non-diarrhea individuals, is unclear. METHODS: We examined data from 368 individuals with and without diarrhea who underwent three-dimensional high-resolution anorectal manometry and balloon expulsion test. All patients completed the Rome III constipation module and the pelvic floor distress inventory (PDFI-20) survey. Patients were considered to have fecal urgency if they reported being bothered "moderately" or "quite a bit" by it in the past 3 months. RESULTS: A total of 103 patients (28.0%) met our definition of fecal urgency. These patients were significantly more likely to meet criteria for irritable bowel syndrome and to report fecal incontinence, urinary incontinence, and diarrhea. Fecal urgency was associated with rectal hypersensitivity in those with diarrhea, but not in those without diarrhea. Fecal urgency was associated with urinary urge incontinence in those without diarrhea, but not those with diarrhea. CONCLUSIONS: In patients with diarrhea, fecal urgency is associated with rectal hypersensitivity, whereas in patients without diarrhea, fecal urgency is associated with urinary urge incontinence. This suggests that fecal urgency has different pathophysiological mechanisms in patients with different underlying bowel habits.

A randomized double-blind trial of clonidine and colesevelam for women with fecal incontinence.

BACKGROUND: Diarrhea and rectal urgency are risk factors for fecal incontinence (FI). The effectiveness of bowel modifiers for improving FI is unclear. METHODS: In this double-blind, parallel-group, randomized trial, women with urge FI were randomly assigned in a 1:1 ratio to a combination of oral clonidine (0.1 mg twice daily) with colesevelam (1875 mg twice daily) or two inert tablets for 4 weeks. The primary outcome was a ≥50% decrease in number of weekly FI episodes. KEY RESULTS: Fifty-six participants were randomly assigned to clonidine-colesevelam (n = 24) or placebo (n = 32); 51 (91%) completed 4 weeks of treatment. At baseline, participants had a mean (SD) of 7.5 (8.2) FI episodes weekly. The primary outcome was met for 13 of 24 participants (54%) treated with clonidine-colesevelam versus 17 of 32 (53%) treated with placebo (p = 0.85). The Bristol stool form score decreased significantly, reflecting more formed stools with clonidine-colesevelam treatment (mean [SD], 4.5 [1.5] to 3.2 [1.5]; p = 0.02) but not with placebo (4.2 [1.9] to 4.1 [1.9]; p = 0.47). The proportion of FI episodes for semiformed stools decreased significantly from a mean (SD) of 76% (8%) to 61% (10%) in the clonidine-colesevelam group (p = 0.007) but not the placebo group (61% [8%] to 67% [8%]; p = 0.76). However, these treatment effects did not differ significantly between groups. Overall, clonidine-colesevelam was well tolerated. CONCLUSIONS AND INFERENCES: Compared with placebo, clonidine-colesevelam did not significantly improve FI despite being associated with more formed stools and fewer FI episodes for semiformed stools.

The impact of transcutaneous electrical acustimulation (TEA) on rectal distension-induced pain in patients with irritable bowel syndrome (IBS)-A study to determine the optimal TEA delivery modalities and effects on rectal sensation and autonomic function.

BACKGROUND: Treatment options for abdominal pain in IBS are inadequate. TEA was reported effective treatment of disorders of gut-brain interaction but its mechanism of action and optimal delivery method for treating pain in IBS are unknown. This study aims to determine the most effective TEA parameter and location to treat abdominal pain in patients with IBS-Constipation and delineate the effect of TEA on rectal sensation and autonomic function. METHODS: Nineteen IBS-C patients underwent TEA at acupoints ST36 (leg), PC6 (wrist), or sham-acupoint. Each patient was studied in five randomized sessions on separate days: (1) TEA/ST36-100 Hz; (2) TEA/ST36-25 Hz; (3) TEA/PC6-100 Hz; (4) TEA/PC6-25 Hz; (5) TEA/Sham-25 Hz. In each session, barostat-guided rectal distention (RD) was performed before and after TEA. Patients graded the RD-induced pain and recorded three rectal sensation thresholds. A heart rate variability (HRV) signal was derived from the electrocardiogram for autonomic function assessment. KEY RESULTS: Studied patients were predominantly female, young, and Caucasian. Compared with baseline, patients treated with TEA/ST36-100 Hz had significantly decreased pain scores at RD pressure-points 20-50 mmHg (p < 0.04). The average pain reduction was 40%. Post-treatment scores did not change significantly with other TEA modalities except with sham-TEA (lesser degree compared to ST36-100 Hz, p = 0.04). TEA/ST36-100, but not other modalities, increased the rectal sensation threshold (first sensation: p = 0.007; urge to defecate: p < 0.026). TEA/ST36-100 Hz was the only treatment that significantly decreased sympathetic activity and increased parasympathetic activity with and without RD (p < 0.04). CONCLUSIONS & INFERENCES: TEA at ST36-100 Hz is superior stimulation point/parameter, compared to TEA at PC-6/sham-TEA, to reduce rectal distension-induced pain in IBS-C patients. This therapeutic effect appears to be mediated through rectal hypersensitivity reduction and autonomic function modulation.

Phantom rectum following abdominoperineal excision for rectal neoplasm: appearance and disappearance.

AIM: The sensation that the rectum remains or is functioning after abdominoperineal excision (APE) is called phantom rectum (PR). Its postoperative and long-term morbidity are not well documented. Informed consent may not include the risk and consequences of this condition. We assessed the incidence and morbidity of PR after APE and compared those with vs those without vertical rectus abdominis myocutaneous flaps. METHOD: Patients who underwent APE between 1 January 2004 and 31 December 2008 were identified. Preoperative radiation and operative reconstruction by vertical rectus abdominis myocutaneous (VRAM) flaps were noted. Patients were interviewed by telephone to assess the presence and timing of PR symptoms and their effect on quality of life. RESULTS: Thirty-six of 80 patients who underwent APE were available for follow-up. Twenty-three (64%) described PR symptoms including urgency to evacuate [22 (61%)], sensation of faeces in the rectum [19 (52%)] and sensation of passing flatus [17 (48%)]. Eleven (47%) who had VRAM vs 25 who did not, reported having symptoms of PR at < 3 months after APE. Patients described their symptoms as 'unchanged over time' [20 (56%)], 'gradually decreasing and ultimately disappearing' [13 (35%)] or 'worsening' [3 (9%)]. Preoperative radiation and laparoscopic approach were not associated with PR symptoms. Significantly more patients having a VRAM flap reported early PR symptoms [7/11 (64%) vs 4/25 (16%)] (P = 0.008). CONCLUSION: PR sensations were experienced by 23 (64%) patients who underwent APE for rectal cancer. VRAM reconstruction was associated with early PR presentation. The possibility of PR should be discussed preoperatively in patients undergoing APE for anorectal neoplasm.

Effects of Age and Sex on the Anorectal Sensory Threshold to Electrical Stimulation: A Single-center Observational Study.

Objectives: Anorectal sensation is an essential component for maintaining normal defecation and continence. This study aimed to investigate changes in anorectal sensation with age and sex using the anorectal sensory threshold to electrical stimulation in a large population with a broad age spectrum. Methods: This study enrolled consecutive adult patients (20-89 years old) who underwent anorectal physiology tests to screen for functional or organic anorectal disease. Anorectal sensitivity was measured using an endoanal electrode with a 45-mm long bipolar needle. A constant electrical current was delivered to the lower end of the rectum and the anal canal. The minimum current in milliamperes at which the initial sensation was felt was defined as the sensory threshold. Results: Overall, 888 patients were included in this study. The most frequent comorbidities were constipation and hemorrhoids. The median sensory threshold for all patients was 0.5 (interquartile range, 0.2-1.5) mA, and the overall sensory threshold was significantly higher in men than in women. The 95% confidence interval of the sensory threshold for men and women were 0.1-6.8 and 0.1-5.1 mA, respectively. The sensory threshold increased significantly with age in both sexes (men, r = 0.384; women, r = 0.410). There was no sex difference in the sensory threshold between ages 20 and 40 years; however, between ages 50 and 70 years, men had a higher sensory threshold than women. Conclusions: The anorectal sensory threshold to electrical stimulation increased with age, and the influence of aging was more significant in men than in women.

Early reported rectal sensation predicts continence in anorectal anomalies.

BACKGROUND: Straining at stool is an automatic reflex in babies and implies the presence of rectal sensation. We hypothesised that early reported rectal sensation would predict future continence in children with anorectal anomalies. AIM OF THE STUDY: The aim of this study is to determine if early straining at stool was a useful predictor of future continence in infants born with high anorectal malformations. METHODS: A retrospective case note review of prospectively collected clinical information was performed with institutional review board approval. All patients with intermediate/high anorectal malformation operated on by a single surgeon from 1984 to 2010 were included. After stoma closure, parents were asked: The responses were noted within the first year of stoma closure and then all patients were followed up until they were at least 3 ½years old and continence could be assessed using the Krickenbeck outcome classification. Data were compared using Fisher's exact test and sensitivity, specificity and positive predictive value (PPV) were calculated. MAIN RESULTS: Forty-eight patients were included in the study. Sixteen (33%) were female (12 cloacal malformation, 3 rectovaginal fistula, 1 rectal atresia) and 32 (66%) were male (6 rectovesical fistulae, 22 rectourethral fistulae, 4 no fistula). Median follow-up was 9.7years (range 3.5-17.9). Twenty-one children were noted by their parents to exhibit early straining at stool after stoma closure. Twenty of them achieved long term continence. The sensitivity of early straining as a predictor for long term continence was 77%, specificity 95% and positive predictive value 95%. CONCLUSION: The presence of early rectal sensation reported by parents is a good predictor of long term continence. This allows more informed discussion with families in the early years of life.

A novel technique for bedside anorectal manometry in humans.

BACKGROUND: Currently, anorectal manometry (ARM), which is used to diagnose defecatory disorders and identify anal weakness in fecal incontinence (FI) is generally conducted in specialized laboratories. Our aims were to compare anorectal functions measured with high-resolution manometry (HRM) and a novel portable manometry device. METHODS: Anal pressures at rest, during squeeze, and simulated evacuation, and rectal sensation were evaluated with portable and HRM in 20 healthy women, 19 women with constipation, and 11 with FI. The relationship between anal pressures measured with portable and HRM was assessed by the concordance correlation coefficient (CCC), Bland Altman test, and paired t-tests. KEY RESULTS: Anal pressures at rest (CCC 0.45; 95% CI: 0.29, 0.58) and during squeeze (CCC 0.60; 95% CI: 0.46, 0.72) measured with portable and HRM were correlated and inversely associated with the risk of FI. During simulated evacuation, the CCC for rectal pressure (0.62; 95% CI: 0.43, 0.76) was greater than that for anal pressure (CCC 0.22; 95% CI: 0.04, 0.39) and the rectoanal gradient (CCC 0.22; 95% CI: 0.02, 0.41). Rectal sensory thresholds for first sensation, the desire to defecate, and urgency measured by portable and HRM were also significantly correlated between techniques. For several parameters, differences between portable and HRM were statistically significant and the Bland Altman test was positive. CONCLUSIONS & INFERENCES: Anorectal pressures and rectal sensation can be conveniently measured by portable manometry and are significantly correlated with high-resolution manometry.

Mechanically evoked cortical potentials: A physiological approach to assessment of anorectal sensory pathways.

BACKGROUND: Normal defaecation involves activation of anorectal mechanoreceptors responsive to pressure and stretch. The aim of this study was to develop selective anal and rectal mucosal light-touch stimulation suitable for measurement of cortical evoked potentials (EPs) in order to explore the sensory arm of these pathways. NEW METHOD: A novel device was manufactured to deliver selective rectal and/or anal light-touch stimulation using a shielded inter-dental brush mounted on a rotating stepper motor (1Hz, 1ms, 15° rotation). Resultant somatosensory EPs recorded with a 32-channel cortical multi-electrode array were compared to those elicited by electrical anorectal stimulation (2mm anal plug electrode [1Hz, 1ms, 10V]). RESULTS: Eighteen anaesthetized female Wistar rats (body mass 180-250g) were studied. Electrical and mechanical stimulation provoked similar maximal response amplitudes (electrical anorectal 39.0µV[SEM 5.5], mechanical anal 42.2µV[8.1], mechanical rectal 45.8µV[9.0]). Response latency was longer following mechanical stimulation (electrical anorectal 8.8ms[0.5], mechanical anal 16.4ms[1.1], mechanical rectal 18.3ms[2.5]). The extent of activated sensory cortex was smaller for mechanical stimulation. Sensory inferior rectal nerve activity was greater during anal compared to rectal mechanical in a subgroup of 4 rats. Evoked potentials were reproducible over 40min in a subgroup of 9 rats. COMPARISON WITH EXISTING METHODS: Cortical EPs are typically recorded in response to non-physiological electrical stimuli. The use of a mechanical stimulus may provide a more localized physiological method of assessment. CONCLUSIONS: To the authors' knowledge these are the first selective brush-elicited anal and rectal EPs recorded in animals and provide a physiological approach to testing of anorectal afferent pathways.