Perception of and adaptation to rectal isobaric distension in patients with faecal incontinence

Altered epithelial barrier functions in the colon of patients with spina bifida

Our objectives were to better characterize the colorectal function of patients with Spina Bifida (SB). Patients with SB and healthy volunteers (HVs) completed prospectively a standardized questionnaire, clinical evaluation, rectal barostat, colonoscopy with biopsies and faecal collection. The data from 36 adults with SB (age: 38.8 [34.1-47.2]) were compared with those of 16 HVs (age: 39.0 [31.0-46.5]). Compared to HVs, rectal compliance was lower in patients with SB (p = 0.01), whereas rectal tone was higher (p = 0.0015). Ex vivo paracellular permeability was increased in patients with SB (p = 0.0008) and inversely correlated with rectal compliance (r = - 0.563, p = 0.002). The expression of key tight junction proteins and inflammatory markers was comparable between SB and HVs, except for an increase in Claudin-1 immunoreactivity (p = 0.04) in SB compared to HVs. TGFβ1 and GDNF mRNAs were expressed at higher levels in patients with SB (p = 0.02 and p = 0.008). The levels of acetate, propionate and butyrate in faecal samples were reduced (p = 0.04, p = 0.01, and p = 0.02, respectively). Our findings provide evidence that anorectal and epithelial functions are altered in patients with SB. The alterations in these key functions might represent new therapeutic targets, in particular using microbiota-derived approaches.Clinical Trials: NCT02440984 and NCT03054415.

Three-dimensional High-resolution Anorectal Manometry in Children With Non-retentive Fecal Incontinence

Background/Aims

Three-dimensional high-resolution anorectal manometry (3D-HRAM) is a precise tool to assess the function of the anorectum. Our aim is to evaluate children diagnosed with non-retentive fecal incontinence (NRFI) using 3D-HRAM.

Methods

In all children diagnosed with NRFI, manometric parameters and 3-dimensional reconstructions of the anal canal subdivided into 8 segments were recorded. All data were compared to raw data that were obtained from asymptomatic children, collected in our laboratory and published previously (C group).

Results

Forty children (31 male; median age, 8 years; range, 5-17) were prospectively included in the study. Comparison of the NRFI group and C group revealed lower values of mean resting pressure (74.4 mmHg vs 89.2 mmHg, P < 0.001) and maximum squeeze pressure (182 mmHg vs 208.5 mmHg, P = 0.018) in the NRFI group. In the NRFI group, the thresholds of sensation, urge and discomfort (40 cm³, 70 cm³, and 140 cm³, respectively) were significantly higher than those in the C group (20 cm³, 30 cm³, and 85 cm³, respectively; P < 0.001). In the NRFI group, 62.5% presented a mean resting pressure above the fifth percentile, and 82.5% of patients presented a maximum squeeze pressure above the fifth percentile. The comparisons between segments obtained from these patients and those obtained from the C group revealed several segments with significantly decreased pressure values in the NRFI group.

Conclusions

Our study demonstrated lower pressure parameters in children with NRFI. In patients with normal resting pressures, 3D-HRAM may reveal segments with decreased pressures, which may play a potential role in the pathomechanism of incontinence.

Toward more accurate measurements of anorectal motor and sensory function in routine clinical practice: validation of high-resolution anorectal manometry and Rapid Barostat Bag measurements of rectal function

BACKGROUND

Measurements of anorectal function using high-resolution anorectal manometry (HR-ARM) and rectal barostat technology provide more reliable results than standard ARM with an elastic balloon; however, HR-ARM results have not been compared to ARM and standard barostat protocols are impractical in routine clinical practice. The aim of this study was to validate HR-ARM against standard ARM and standard barostat against a novel Rapid Barostat Bag (RBB) measurement and elastic balloon measurements of rectal function.

METHODS

Twenty-six healthy volunteers (15 female, 11 male, 19-52 years) were studied. Measurements of anal function and simulated defecation were compared for 12-sensor HR-ARM and 6-sensor standard ARM using line plots from the same recording. Rectal capacity, compliance, and sensation (volume threshold) were measured by elastic balloon, standard barostat, and RBB methods using stepwise inflation of a 700-mL polyethylene bag to 40 mmHg distension by electronic barostat and handheld syringe monitored by sphygmo-manometer, respectively. Results are reported as mean ± SD. Bland-Altman plots and correlation coefficients (r) for measurements were calculated.

KEY RESULTS

There was excellent agreement between HR- and standard ARM measurements (r > 0.86, <25 mmHg difference) and between standard barostat and RBB measurements of rectal capacity (r = 0.97, <25 mL difference). Correlation coefficients of threshold volumes for initial perception, urgency and discomfort were 0.37, 0.71, and 0.95, respectively. No significant correlation was present with elastic balloon measurements. Time to complete studies was shorter for HR-ARM than standard ARM and for RBB than standard barostat in historical controls.

CONCLUSIONS & INFERENCES

HR-ARM with RBB measurements of anorectal function provides quick and reasonably accurate measurements of continence function suitable for use in routine clinical practice (ClinicalTrial.gov NCT01456442).

Effects of transcutaneous tibial nerve stimulation on anorectal physiology in fecal incontinence: a double-blind placebo-controlled cross-over evaluation

BACKGROUND

Transcutaneous electrical tibial nerve stimulation (TENS) is of growing interest for the treatment of fecal incontinence (FI), but its mechanism of action remains uninvestigated. We aimed to further assess the anorectal response to TENS in a dynamic model.

METHODS

We performed a placebo-controlled, randomized, double-blinded crossover study in 19 patients suffering from FI to assess the effects of TENS on anorectal function. Anorectal physiology and perception were recorded through two sequences of rectal isobaric distension using an electronic barostat device to measure anal and rectal pressures, rectal volumes, and perception scores.

KEY RESULTS

Maximal rectal pressure and volume variation were affected by TENS, with higher mean maximal rectal pressure (5.33 and 4.06 mmHg in the active and sham TENS respectively, p < 0.0001) and lower volume variation (11.45 and 14.7 mL in the active and sham stimulation respectively, p < 0.05). Rectal compliance was not modified by active TENS. Pressure of the upper anal canal was significantly lower with raised isobaric distension in sequences assigned to active TENS.

CONCLUSIONS & INFERENCES

Acute TENS modified anorectal physiology by strengthening the myogenic response to distension rather than increasing muscle relaxation and related rectal compliance in patients with FI.

The utility of conditioning sequences in barostat protocols for the measurement of rectal compliance

AIM

A barostat can be used to measure rectal sensitivity, compliance and elastance all of which are potentially important physiological parameters in the pathophysiology of faecal incontinence. Current practice recommends a conditioning distension sequence be performed prior to index distensions. We questioned the validity of this by comparing values for rectal compliance during sequential conditioning (CD) and index (ID) distensions in physiologically normal subjects.

METHOD

Ten subjects (five men, mean age 55.2 years) with normal anal canal manometry, anorectal sensitivity and balloon distension thresholds were studied. After determining the minimum distension pressure, subjects underwent sequential isobaric distensions: CD 4 mmHg distensions every 45 s and ID 4 mmHg every 2 min, both to a maximum of 24 mmHg or patient tolerance. Compliance values from both sequences were calculated by measuring the maximum slope of pressure-volume curves. A paired t-test was performed to compare any differences between sequences.

RESULTS

Mean rectal compliance were 11.4 ml/mmHg (SD 5.8 ml/mmHg) and 10.9 ml/mmHg (SD 5.7 ml/mmHg) in the CD and ID, respectively, with no statistical difference noted between distensions (P = 0.78).

CONCLUSION

Rectal compliance can be measured with a single distension protocol without the need for an initial conditioning distension. Conditioning the rectum adds additional complexity to barostat protocols and is not necessary.

Effect of rectal distension on voluntary external anal sphincter function in healthy subjects

AIM

Quantification of the anorectal reflex function is critical for explaining the physiological control of continence. Reflex external anal sphincter activity increases with rectal distension in a dynamic response. We hypothesized that rectal distension would similarly augment voluntary external anal sphincter function, quantified by measuring the anal maximum squeeze pressure.

METHOD

Fifty-seven subjects (32 men, 25 women; median age 62 years), with normal anal canal manometry and endoanal ultrasound results, underwent a rectal barostat study with simultaneous anal manometry. Stepwise isovolumetric 50-ml distensions (n=35) or isobaric 4-mmHg distensions (n=22) above the minimum distending pressure were performed (up to 200 ml or 16 mmHg respectively), whilst anal resting pressure and maximum squeeze pressure were recorded and compared with the baseline pressure.

RESULTS

The distension-induced squeeze increment was calculated as the maximum percentage increase in maximum squeeze pressure with progressive rectal distension. This was observed in 53 of the 57 subjects as a mean ± standard deviation (range) increase of 32.8 ± 24.1 (-5.5 to 97.7)%. The mean ± standard deviation (range) distension-induced squeeze increment in male subjects was 36.1 ± 25.7 (-5.5 to 97.7)% and in female subjects was 28.1 ± 20.1 (-3.8 to 70.2)%. There was no significant difference between the sexes (P=0.194).

CONCLUSION

Rectal distension augments external anal sphincter function, confirming the existence of a dynamic rectoanal response. This may represent a quantifiable and important part of the continence mechanism.

Impact of sleep dysfunction on anorectal motility in healthy humans

BACKGROUND/AIMS

Sleep dysfunction is associated with altered gastrointestinal function and subsequently exacerbations of gastrointestinal problems. We aimed to investigate whether sleep dysfunction would influence anorectal motility as determined by anorectal manometry. The effect of anxiety on anorectal motility was also determined.

METHODS

A total of 24 healthy volunteers underwent anorectal manometry. The anorectal parameters included resting and squeeze sphincter pressure, sensory thresholds in response to balloon distension, sphincter length, rectal compliance, and rectoanal inhibitory reflex. Sleep dysfunction was subjectively assessed by using Pittsburgh Sleep Quality Index (PSQI). Anxiety was assessed by the application of the State-Trait Anxiety Inventory questionnaire.

RESULTS

There were sixteen subjects without sleep dysfunction (7 women; mean age, 22 years) and eight subjects with sleep dysfunction (2 women; mean age, 22 years). There was no group difference in the volume threshold for rectoanal inhibitory reflux, rectal compliance or sphincter length (P = NS). Anal sphincter pressure did not differ between the groups (P = NS). The rectal sensitivity for different levels of stimulation did not differ between the groups (P = NS). Sleep quality as determined by PSQI correlated with rectal compliance (r = 0.66, P = 0.007). Although there was no differences in any manometric parameters between subjects with and without anxiety, the anxiety score correlated with rectal compliance (r = 0.57, P = 0.003).

CONCLUSIONS

Despite a positive association between rectal compliance and the level of subjective sleep or anxiety, sleep dysfunction did not apparently affect most of anorectal function in healthy subjects, nor did anxiety.

The physiology of continence and evacuation

Continence is maintained by the coordinated function of the pelvic floor, rectum and anal sphincters. Evacuation occurs through a relaxed pelvic floor. The rectum acts to either store or expel stool both of which require cortical sensory awareness acting in conjunction with intramural and spinal reflexes that ensure timely defecation. The anal sphincters act individually and in unison in response to rectal distension and the sensation of rectal filling. Reflex relaxation of the internal anal sphincter has an additional sensory function in allowing sampling of rectal contents in the upper anal canal. Voluntary control of the external anal sphincter is key in the voluntary deferring of evacuation until a socially opportune moment. This review describes the physiological roles of each of these continence organs in order to understand the complex process of defecation.

Overt rectal prolapse and fecal incontinence

PURPOSE

Rectal prolapse is frequently associated with fecal incontinence; however, the relationship is questionable. The study was designed to evaluate fecal incontinence in a large consecutive series of patients who suffered from rectal prolapse, focusing on both past history, anal physiology, and imaging.

METHODS

Eighty-eight consecutive patients who suffered from an overt rectal prolapse (72 women, 16 men; mean age, 51.1 +/- 19.5 years) as a main symptom were analyzed; 48 patients also experienced fecal incontinence compared with 40 without incontinence. Logistic regression analyses were performed.

RESULTS

The two groups of patients did not differ with respect to parity, weekly stool frequency, main duration of symptoms before referral, occurrence of dyschezia, and digital help to defecate. Patients with prolapse who were older than 45 years (odds ratio (OR), 4.51 (1.49-13.62); P = 0.007) and those with a past history of hemorrhoidectomy (OR, 9.05 (1.68-48.8); P = 0.01) were significantly more incontinent. Incontinent group showed frequent internal anal sphincter defect compared with the continent group (60 vs. 6.2 percent; P = 0.0018).

CONCLUSIONS

In patients with overt rectal prolapse, the occurrence of fecal incontinence needs special consideration for age and previous hemorrhoid surgery as causative factors. Anal weakness and sphincter defects are frequently observed.

Rectal sensorimotor dysfunction in women with fecal incontinence

The rate and pattern of rectal distension affect rectal distensibility, perception, and anal relaxation in health. Because rectal urgency is a prominent symptom in fecal incontinence (FI), we assessed rectal distensibility, contractions, perception, and anal pressures during rectal distention in 21 healthy, asymptomatic women (age 61 +/- 2 yr, mean +/- SE) and 51 women with FI (60 +/- 2 yr). Rectal staircases (0-32 mmHg, 4-mm steps) and ramp distensions [0-200 ml at 25, 50, and 100 ml/min with a phase of sustained distension (SD), lasting 1 min, between inflation and deflation]. The rectum was stiffer during rapid than slow ramp distention. This effect was more prominent at a lower volume (50 ml) and was also more pronounced in older subjects and in FI. A rectal contractile response was observed not only during inflation but also during SD and during deflation. During inflation, this contractile response was rate dependent in controls but not in FI. During staircase but not ramp distentions, the threshold for the desire to defecate was lower in FI. During ramp distentions, the duration of perception was significantly longer in FI. The rate of distention did not affect rectal perception (i.e., sensory thresholds or duration of perception) during ramp distentions. Baseline anal pressures and the magnitude of anal relaxation during rectal distention were also reduced in FI. In addition to reduced rectal capacity and compliance, women with FI had an exaggerated rate-dependent reduction in rectal distensibility, lower sensory thresholds, and more prolonged perception, indicative of rectoanal dysfunctions.

Barostat measurement of rectal compliance and capacity

PURPOSE

Fecal continence requires relaxation of the rectal wall and a reservoir of adequate capacity. Rectal compliance provides an assessment of rectal wall stiffness; however, compliance is also affected by rectal capacity. We developed and validated a barostat measurement of rectal capacity. By accounting for variation in rectal capacity, we aimed to improve the inconsistent relationship between rectal compliance, sensation, and continence reported in the literature.

METHOD

Barostat measurements of rectal compliance and capacity were validated in 41 healthy, continent subjects. Slow staircase (0-40 mmHg) and rapid phasic (12-40 mmHg) distentions were performed on two separate days, filling sensations were assessed by visual analog score. A stool substitute retention test of rectal filling sensation and continence was performed.

RESULTS

Variance of volume measurements decreased with pressure comparing conditioning vs. index distentions, staircase vs. phasic distentions, and measurements on different days (all P < 0.001). Correction for rectal capacity measured at 40 mmHg reduced the "normal range" of compliance measurements (P < 0.01) but not vice versa. Compared with unadjusted volume measurements, normalized rectal volume (percentage filling relative to rectal capacity) improved the description of rectal sensation visual analog score (P < 0.01). Rectal capacity correlated with filling sensations and the volume retained on retention testing (P < 0.01).

CONCLUSION

Barostat measurements of rectal capacity at 40 mmHg are highly reproducible and not affected by distention protocol. The assessment of rectal capacity complements that of rectal compliance. Correction for rectal capacity provides an assessment of rectal wall stiffness independent of rectal geometry and improves the association of barostat volume measurements with rectal sensitivity and continence.

Low rectal volumes in patients suffering from fecal incontinence: what does it mean?

BACKGROUND

Rectal perception and adaptation to distension are widely heterogeneous in subjects with faecal incontinence.

AIM

To quantify rectal physiology in patients with incontinence and low maximum rectal volume, according to AGA guidelines on anorectal testing techniques.

PATIENTS AND METHODS

148 patients (12 men, 136 female) with incontinence to liquid and/or solid stools were investigated. Distending isobaric procedures were carried out using an electronic barostat in order to analyse perception and adaptation of the rectum.

RESULTS

Pain during isovolumic rectal distension at a level of 100 mL or less was experienced in 21 subjects (14.2%). As defined by isobaric distensions, incontinent patients with low MTV had more frequently a hypocompliant rectum (62%) when compared with those with higher MTV (31%, P = 0.046). Perception scores tended to be higher at each step of distending rectal pressure: incontinent patients with low MTV had more frequently a hypersensitive rectum (48%) when compared with those with normal or high MTV (24%, P = 0.035). Only four of 21 incontinent subjects with low MTV had an isolated hypersensitive rectum.

CONCLUSION

Both sensitivity and compliance are altered in patients with low MTV. A more extensive study of the role of sensory and compliance aspects of subjects with incontinence is warranted.

Rectal sensorimotor dysfunction in patients with urge faecal incontinence: evidence from prolonged manometric studies

BACKGROUND AND AIMS

Although external anal sphincter dysfunction is the major cause of urge faecal incontinence, approximately 50% of such patients have evidence of rectal hypersensitivity and report exaggerated stool frequency and urgency. The contribution of rectosigmoid contractile activity to the pathophysiology of this condition is unclear, and thus the relations between symptoms, rectal sensation, and rectosigmoid motor function were investigated.

METHODS

Fifty two consecutive patients with urge faecal incontinence, referred to a tertiary surgical centre, and 24 volunteers, underwent comprehensive anorectal physiological investigation, including prolonged rectosigmoid manometry. Patients were classified on the basis of balloon distension thresholds into those with rectal hypersensitivity (n = 27) and those with normal rectal sensation (n = 25). Automated quantitative analysis of overall rectosigmoid contractile activities and, specifically, high amplitude contractions and rectal motor complex activity was performed.

RESULTS

External anal sphincter dysfunction was similar in both patient groups. Overall, phasic activity and high amplitude contraction frequency were greater, and rectal motor complex variables significantly altered, in those with rectal hypersensitivity. Symptoms, more prevalent in the rectal hypersensitivity group, were also more often associated with rectosigmoid contractile events. For individuals, reduced compliance and increased rectal motor complex frequency were only observed in patients with rectal hypersensitivity.

CONCLUSIONS

We have identified a subset of patients with urge faecal incontinence-namely, those with rectal hypersensitivity-who demonstrated increased symptoms, enhanced perception, reduced compliance, and exaggerated rectosigmoid motor activity. Comprehensive assessment of rectosigmoid sensorimotor function, in addition to evaluation of anal function, should be considered in the investigation of patients with urge faecal incontinence.

Rectal hypersensitivity worsens stool frequency, urgency, and lifestyle in patients with urge fecal incontinence

PURPOSE

Rectal sensory mechanisms are important in the maintenance of fecal continence. Approximately 50 percent of patients with urge incontinence have lowered rectal sensory threshold volumes (rectal hypersensitivity) on balloon distention. Rectal hypersensitivity may underlie the heightened perception of rectal filling; however, its impact on fecal urgency and incontinence is unknown. This study was designed to investigate the impact of rectal hypersensitivity in patients with urge fecal incontinence.

METHODS

Prospective and retrospective audit review of all patients (n = 258) with an intact native rectum referred to a tertiary colorectal surgical center for physiologic investigation of urge fecal incontinence during a 7.5-year period. Patients with urge fecal incontinence who had undergone pelvic radiotherapy (n = 9) or rectal prolapse (n = 6) were excluded.

RESULTS

A total of 108 of 243 patients (44 percent) were found to have rectal hypersensitivity. The incidence of anal sphincter dysfunction was equal (90 percent) among those with or without rectal hypersensitivity. Patients with urge fecal incontinence and rectal hypersensitivity had increased stool frequency (P < 0.0001), reported greater use of pads (P = 0.003), and lifestyle restrictions (P = 0.0007) compared with those with normal rectal sensation, but had similar frequencies of incontinent episodes.

CONCLUSIONS

Urge fecal incontinence relates primarily to external anal sphincter dysfunction, but in patients with urge fecal incontinence, rectal hypersensitivity exacerbates fecal urgency, and this should be considered in the management and surgical decision in patients who present with fecal incontinence.

The pathophysiology of faecal spotting in obese subjects during treatment with orlistat

BACKGROUND

The intermittent loss of oil or liquid faeces ('spotting') is an adverse effect that occurs in obese patients during treatment with the lipase inhibitor orlistat; the pathophysiology is unknown.

AIM

To investigate the effects of orlistat on anorectal sensorimotor function and continence.

METHODS

Obese subjects susceptible to spotting were identified by an unblind trial of orlistat. Obese spotters (n = 15) and non-spotters (n = 16) completed a randomized, double-blind, cross-over trial of orlistat and placebo. Anorectal function was assessed by rectal barostat and anal manometry, together with a novel stool substitute retention test, a quantitative measurement of faecal continence.

RESULTS

Orlistat increased stool volume and raised faecal fat and water. Treatment had no effect on anorectal motor function, but rectal sensation was reduced; on retention testing, the volume retained was increased. Subjects susceptible to spotting had lower rectal compliance, heightened rectal sensitivity and weaker resting sphincter pressure than non-spotters. On retention testing, gross continence was maintained; however, spotters lost small volumes of rectal contents during rectal filling.

CONCLUSION

Treatment with orlistat has no direct adverse effects on anorectal function or continence. Spotting occurs during treatment with orlistat when patients with sub-clinical anorectal dysfunction are exposed to increased stool volume and altered stool composition.

Outcome measures for fecal incontinence: anorectal structure and function

Fecal incontinence is a symptom attributable to a variety of disorders affecting one or more factors that maintain continence. Objective assessments should complement symptom assessments as outcome measures in therapeutic trials; conceivably, these assessments may also predict the response to therapy. Consistent with existing trends, most therapeutic trials should incorporate anal sphincter pressures and rectal sensation as outcome variables, paying meticulous attention to techniques. Rectal sensation is increased after pelvic floor retraining by biofeedback therapy in fecal incontinence; however, the predictive value of improved anal pressures after biofeedback has not been clearly established. Other factors maintaining continence can be assessed by newer approaches. In addition to assessing rectal sensation, a barostat also measures rectal compliance; alterations in rectal compliance modulate rectal perception. Particularly appropriate end points for trials involving surgical repair are sphincter integrity, assessed by endoanal ultrasound or magnetic resonance imaging (MRI), and puborectalis and pelvic floor motion, assessed by dynamic MRI. Despite disagreement about which technique is superior for evaluating the internal sphincter, MRI performs the same or better than ultrasound for assessing the external sphincter. The utility of measuring pudendal nerve latencies as a marker of pudendal nerve injury is limited; needle electromyography provides a sensitive measure of denervation and can usually identify myopathic damage, neurogenic damage, or mixed injury. These standardized, reproducible assessments of the multifaceted mechanisms maintaining fecal incontinence should be incorporated as outcome variables in therapeutic trials of fecal incontinence.

Rectal compliance, capacity, and rectoanal sensation in fecal incontinence

OBJECTIVE

Assessments of the pathophysiology of fecal incontinence are skewed toward anal sphincter function; however, rectal compliance, rectoanal sensation and capacity may also be relevant. The aim of this study was to evaluate the usual and some novel diagnostic approaches in fecal incontinence.

METHODS

In 22 unselected patients with fecal incontinence (21 F, 33-75 yr), we quantified: 1) symptoms, anorectal manometry, and anal ultrasound; 2) anal perception of temperature and light touch; 3) rectal sensitivity and compliance to distension; and 4) rectal reservoir function. Control values were obtained from two groups of 11 (seven F, 32-53 yr), and 32 (18 F, 19-44 yr) volunteers.

RESULTS

Patients had urge (14), passive (four), or combined (four) fecal incontinence; symptoms were mild in three, moderate in nine, and severe in 10 patients. Most had low sphincteric pressures and ultrasonic abnormalities. Temperature perception was impaired (p < 0.05) in incontinent patients, to a greater extent in the proximal anal canal and in patients with passive, as opposed to urge, incontinence. Intraluminal pressures for sensations of rectal distension were lower in incontinent patients (p = 0.02). Artificial stools elicited sensations of rectal filling at lower volumes than did a barostat bag, and in patients with urge, as opposed to passive, incontinence. In patients and controls, the sensation of urgency was associated (r2 = 0.2, p < 0.01) with rectal compliance.

CONCLUSIONS

We confirm that temperature sensation is impaired, and perception of rectal distension is not always reduced in fecal incontinence. Artificial stool tended to induce sensations at lower volumes than did balloon inflation. Altered sensory mechanisms may contribute to the pathophysiology of fecal incontinence.