Resting anal pressure, not outlet obstruction or transit, predicts healthcare utilization in chronic constipation: a retrospective cohort analysis

Clinical Utility of Anorectal Manometry in Children with Functional Constipation: Can Anorectal Manometry Help Predict the Therapeutic Response?

Background: Anorectal Manometry (ARM) plays a crucial role in diagnosing potential motility disorders of anorectum in pediatric gastroenterology. Despite its prevalence, the predictive utility of ARM in guiding therapeutic response remains poorly characterized. Objectives: This study aims to evaluate the effectiveness of ARM in predicting therapeutic responses among children with functional constipation. Methods: A retrospective chart review was conducted at two tertiary centers examining pediatric patients who underwent ARM between January 2018 and July 2022. Key ARM parameters were analyzed, including anal resting pressure, recto-anal inhibitory reflex (RAIR), first rectal sensation, and bear-down maneuver (BDM). Therapeutic responses were assessed post-ARM, with success defined as an increase in bowel movement frequency and/or a decrease in fecal incontinence. In addition, we also intended to evaluate the eventual need for surgical intervention as another outcome. Results: The study included 327 patients, with a median age of 8.2 years. The overall therapeutic response rate was 40.7%, with stimulant laxatives showing a 48% response. Notably, lower anal resting pressures and delayed rectal sensations were associated with better therapeutic outcomes. Abnormal BDM correlated with a lack of response to therapies, while the presence of abnormal RAIR was linked to a higher eventual need for surgical intervention. Conclusions: ARM is instrumental in predicting therapeutic responses in pediatric patients with functional constipation. In addition to diagnosing HD, ARM could be an instrumental tool in identifying patients with dyssynergic defecation for early intervention with targeted therapy in age-appropriate patients.

Latent profile analysis reveals the central role of psychological symptoms in driving disease severity in chronic constipation

BACKGROUND

Chronic constipation (CC) is defined by symptom criteria reflecting heterogenous physiology. However, many patients with CC have significant psychological comorbidities-an alternative definition using a biopsychosocial classification model could be warranted to inform future treatments. We sought to: (1) empirically derive psychological symptom profiles of patients with CC using latent profile analysis and (2) validate these profiles by comparing them on symptom severity, GI-specific anxiety, body mass index (BMI), and anorectal manometry findings.

METHODS

Participants included adults presenting for anorectal manometry for CC (N = 468, 82% female, Mage = 47). Depression/anxiety symptoms and eating disorder (ED) symptoms (EAT-26) were used as indicators (i.e., variables used to derive profiles) representing unique psychological constructs. Constipation symptoms, GI-specific anxiety, BMI, and anorectal manometry results were used as validators (i.e., variables used to examine the clinical utility of the resulting profiles).

KEY RESULTS

A 5-profile solution provided the best statistical fit, comprising the following latent profiles (LPs): LP1 termed "high dieting, low bulimia;" LP2 termed "high ED symptoms;" LP3 termed "moderate ED symptoms;" LP4 termed "high anxiety and depression, low ED symptoms;" and LP5 termed "low psychological symptoms." The low psychological symptom profile (61% of the sample) had lower abdominal and overall constipation severity and lower GI-specific anxiety compared to the four profiles characterized by higher psychological symptoms (of any type). Profiles did not significantly differ on BMI or anorectal manometry results.

CONCLUSIONS AND INFERENCES

Profiles with high psychological symptoms had increased constipation symptom severity and GI-specific anxiety in adults with CC. Future research should test whether these profiles predict differential treatment outcomes.

The oral cavity and intestinal microbiome in children with functional constipation

Constipation is a widespread problem in paediatric practice, affecting almost 30% of children. One of the key causal factors of constipation may be disturbances in the homeostasis of the gastrointestinal microbiome. The aim of the study was to determine whether the oral and fecal microbiomes differ between children with and without constipation. A total of 91 children over three years of age were included in the study. Of these, 57 were qualified to a group with constipation, and 34 to a group without. The saliva and stool microbiomes were evaluated using 16S rRNA gene amplicon sequencing. Functional constipation was associated with characteristic bacterial taxa in the fecal microbiota. Statistically significant differences were found at the family level: Burkholderiaceae (q = 0.047), Christensenellaceae (q = 0.047), Chlostridiaceae (q = 0.047) were significantly less abundant in the constipation group, while the Tannerellaceae (q = 0.007) were more abundant. At the genus level, the significant differences were observed for rare genera, including Christensenellaceae r-7 (q = 2.88 × 10-2), Fusicatenibacter (q = 2.88 × 10-2), Parabacteroides (q = 1.63 × 10-2), Romboutsia (q = 3.19 × 10-2) and Subdoligranulum (q = 1.17 × 10-2). All of them were less abundant in children with constipation. With the exception of significant taxonomic changes affecting only feces, no differences were found in the alpha and beta diversity of feces and saliva. Children with functional constipation demonstrated significant differences in the abundance of specific bacteria in the stool microbiome compared to healthy children. It is possible that the rare genera identified in our study which were less abundant in the constipated patients (Christensellaceae r-7, Fusicatenibacter, Parabacteroides, Romboutsia and Subdoligranulum) may play a role in protection against constipation. No significant differences were observed between the two groups with regard to the saliva microbiome.

Prevalence of double incontinence in patients with fecal incontinence undergoing anorectal manometry and discriminating factors

Background: Double incontinence (DI) is the concomitant presence of incontinence for urine and stool. Aim of this study is to assess prevalence of DI in patients with fecal incontinence (FI) undergoing Ano-Rectal Manometry (ARM) in a tertiary care center and to identify factors discriminating between both. Methods: Medical records of consecutive patients referred for ARM for FI during 2 years at University Hospital Brussels were retrospectively reviewed. Results from ARM, presence of diarrhea, diseases from recto-anal or peri-anal region, prior abdominal, proctological or urological surgery and neurological comorbidities were recorded. Results: Of 101 enrolled patients, 77% suffered from solitary FI and 23% from DI. Diarrhea was more common in DI vs. FI (43,5% vs. 15,4%, P=.008), as was the presence of neurological comorbidities (34.8% vs. 10.3%, P=.009) and urological interventions (21.7% vs. 1.3%, P=.002). In respect to women only, more urological interventions were performed (20% vs. 0%, P=.006) and more diseases from recto-anal or peri-anal region were encountered in DI vs. FI (35.0 % vs. 12.5 %, P= .045). In men, neurological disorders were significantly more common in DI (100.0% vs. 3.3%, P=.002). Conclusions: This study identified gender-specific patterns of comorbidities in FI and DI. ARM had no distinctive value between FI and DI in men and women. A prospective study should provide more information on patients at risk for incontinence and help to identify distinct features between FI and DI in men and women.

High Anal Canal Pressure and Rectal Washouts Contribute to the Decrease of Anal Basal Pressure After Botulinum Toxin Injections in Paediatric Patients With Chronic Constipation

INTRODUCTION

Chronic constipation can be treated by injecting botulinum toxin into the anal sphincter to decrease anal basal pressure. To assess the effect of botulinum toxin, we investigated the factors that contribute to changes in anal basal pressure after injection.

METHODS

This was a retrospective study conducted in a tertiary hospital in the Netherlands. We included children with chronic constipation treated with botulinum toxin injections and measured anal basal pressure before and after each injection. Multivariable linear regression analyses were used.

RESULTS

We investigated 30 cases with idiopathic constipation. Their median age was 20.5 (7.75-53.25) months. Anal basal pressure decreased after injection in 20 cases. The mean decrease of anal basal pressure after injection was 18.17 ± 35.22 mmHg. The anal basal pressure change was linearly correlated with preinjection pressure (R ² = 0.593, P < 0.001). A significant decrease of pressure was observed in patients with preinjection pressure > 70 mmHg. Preinjection anal basal pressure (β = -0.913, P < 0.001) and rectal washouts (β = -21.015, P = 0.007) contributed significantly to pressure changes. Changes in anal basal pressure were also significantly associated with patients' weights (β = 0.512, 95% CI, 0.011-1.013) and sex (β = 22.971, 95% CI, 9.205-36.736).

CONCLUSIONS

Botulinum toxin significantly decreases anal basal pressure when preinjection pressure is higher than 70 mmHg. In patients with severely elevated anal basal pressure, we recommend rectal washouts to promote the decrease of anal basal pressure.

Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation

BACKGROUND

Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting.

PURPOSE

This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

Effect of biofeedback combined with high-quality nursing in treatment of functional constipation

BACKGROUND

Functional constipation (FC) is a common functional gastrointestinal disease with various clinical manifestations. It is a physical and mental disease, which seriously affects patient physical and mental health and quality of life. Biofeedback therapy is the treatment of choice for FC, especially outlet obstructive constipation caused by pelvic floor dysfunction. High-quality nursing is a new nursing model in modern clinical work and a new concept of modern nursing service.

AIM

To explore the effect of biofeedback combined with high-quality nursing in the treatment of FC.

METHODS

A total of 100 patients with FC admitted to our hospital from March 2015 to July 2019 were selected for clinical observation. These patients were randomly divided into two groups of 50: Experimental group (biofeedback combined with high-quality nursing treatment group) and control group (biofeedback group).

RESULTS

The constipation symptom score of the experimental group was significantly lower than that of the control group, and the difference was statistically significant (P < 0.05). The anal canal resting pressure and initial defecation threshold of the experimental group were significantly lower than those of the control group, and the maximum squeeze systolic pressure of the anal canal of the experimental group was significantly higher than that of the control group (P < 0.05). The Self-Rating Anxiety Scale and Zung's Self-Rating Depression Scale scores of the two groups were significantly lower than before treatment. The Self-Rating Anxiety Scale and Self-Rating Depression Scale scores of the experimental group were significantly lower than those of the control group (P < 0.05). The patient satisfaction score of the experimental group was significantly higher than that of the control group (P < 0.05).

CONCLUSION

The application of biofeedback combined with high-quality nursing in the treatment of FC has significant advantages over pure biofeedback treatment, and it is worthy of promotion in clinical work.

A new method for assessing anal distensibility with a barostat and magnetic resonance imaging in healthy and constipated women

OBJECTIVES

Defecation requires relaxation of the internal and external anal sphincters. High anal resting pressure is associated with painful constipation, defecatory disorders, and increased healthcare utilization in constipated patients; the mechanisms are unclear. Perhaps patients with a high anal resting pressure have a less distensible canal, which impedes defecation.

METHODS

In 50 of 64 participants (33 healthy and 17 constipated women), anal pressures and distensibility were measured, respectively, with manometry and balloon distention combined with magnetic resonance imaging; rectal balloon expulsion time (BET) was also studied.

RESULTS

The BET (P = .006) was longer, and the mean (SD) rectoanal pressure gradient (-58[40] vs -34[26] mm Hg, P = .03) was more negative in constipated than healthy women; anal resting pressure was not different. During anal distention, the balloon expanded rapidly at an opening pressure of 49 (18) mm Hg, which was lower (P < .0001) than resting pressure (90 [25] mm Hg). The resting pressure was correlated with the opening pressure (r = 0.57, P < .0001) and inversely (r = -0.38, P = .007) with maximum volume but not with anal distensibility (volume-pressure slope). In healthy women, the difference (opening-resting pressure) was correlated with anal relaxation during evacuation (r = 0.35, P = .04). Anal distensibility and sensory thresholds were not different between constipated and healthy women.

CONCLUSIONS

Among healthy and constipated women, a greater anal resting pressure is correlated with greater opening pressure and lower maximum volume during distention, and, hence, provides a surrogate marker of anal distensibility. The difference (opening-resting pressure), which reflects anal relaxation during distention, is correlated with anal relaxation during evacuation. Anal resting pressure and distensibility were comparable in healthy and constipated women.

Dyssynergic Defecation and Anal Sphincter Disorders in Children in High-Resolution Anorectal Manometry Investigation

OBJECTIVES

Dyssynergic defecation is a common disorder in children with functional constipation (FC) because of relaxation disorders of the sphincter apparatus and intra-rectal pressure during defecation. The aim of the study was to determine frequency and type of dyssynergic defecation and to assess pressure in the anal canal poles during simulated evacuation and function of puborectalis muscle in defecation in children with FC.

METHODS

Three-dimensional (3D) high-resolution anorectal manometries (3D HRAM) were performed in 131 children with FC. In the manometric test, resting pressure measurements were assessed in 4 measuring poles of the anal canal.

RESULTS

One hundred thirty-one children ages 5 to 17 years (mean age 10.2; SD ± 3.8; median 10) were involved in the study (69 girls and 62 boys). Dyssynergic defecation was shown in 106/131 (80.9%) examined children. A statistically significant difference between the age of examined children (P < 0.02) and intrarectal pressures at the anal canal measuring points (left P < 0.009, right P < 0.005, anterior P < 0.01) was found. Correlation between the residual pressure values in lateral anal canal measurement poles and intrarectal pressure was demonstrated in all types of dyssynergy (left: r = 0.69, P < 0.0005; right: r = 0.74, P < 0.0005). In a group of 53/131 (40.5%) children, 3D HRAM showed a rectal pressure increase during simulated defecation, because of the dysfunction of the puborectalis muscle.

CONCLUSION

The increase in sphincter pressure in lateral and posterior poles in I and II types of dyssynergia and in lateral poles in other types of dyssynergia may depend on relaxation disorders of the puborectalis muscle during defecation.

Ameliorating Effects of Transcutaneous Electrical Acustimulation at Neiguan (PC6) and Zusanli (ST36) Acupoints Combined with Adaptive Biofeedback Training on Functional Outlet Obstruction Constipation

BACKGROUND

Stimulant laxatives are still considered the most common treatment for functional outlet obstruction constipation (FOOC). However, the effectiveness of laxatives is unsatisfactory, and the long-term use of laxatives may cause certain adverse events. With this in mind, it is, however, paramount that novel complementary treatment(s) and/or other forms of alternative medicine are adequately investigated.

AIMS

The study aims to explore the effects and potential mechanism(s) of transcutaneous electrical acustimulation (TEA) combined with adaptive biofeedback training (ABT) on FOOC.

METHODS

A total of forty-five patients with FOOC were recruited and were randomly assigned to receive either Macrogol 4000 Powder (MAC, 10 g bid) (group A, n = 15) only, ABT + MAC + Sham-TEA (group B, n = 15), or TEA + ABT + MAC (group C, n = 15) in a six-week study. Individual patients' constipation-symptoms (PAC-SYM) and constipation-quality of life (PAC-QOL) were both assessed and scored. Serum acetylcholine (Ach) and nitric oxide (NO) were measured from drawn blood samples while individual patients' heart rate variability (HRV) was calculated at baseline and after each corresponding therapy. Anorectal manometry and balloon expulsion test were both performed before and after treatment.

RESULTS

Firstly, participants in group C had significantly lower scores of PAC-SYM, PAC-QOL, and a decreased anal defecating pressure (ADP) as compared to participants in group B (all p < 0.050). These results, however, suggest the TEAs effect. Secondly, the low-frequency band (LF)/(LF + HF) ratio in groups B and C were decreased as compared to group A (p=0.037, p=0.010, respectively) regarding HRV. On the other hand, the high-frequency band (HF)/(LF + HF) ratio in groups B and C showed an opposite outcome. Finally, the serum Ach in groups B and C was significantly higher as compared to group A (p=0.023, p=0.012, respectively). Of significant importance, the serum NO in groups B and C were notably low as compared to group A (p=0.001, p < 0.001, respectively).

CONCLUSIONS

TEA, combined with ABT, effectively improves constipation symptoms as well as QOL in FOOC patients. It is, however, achieved by decreasing ADP, which mechanisms are mediated via the autonomic and enteric mechanisms.

Patient dissatisfaction with medical therapy for chronic constipation or irritable bowel syndrome with constipation: analysis of N-of-1 prospective trials in 81 patients

BACKGROUND

Patients with chronic constipation (CC) or with irritable bowel syndrome with constipation are often dissatisfied about their medical therapy, but their condition remains poorly defined.

AIM

To evaluate the patients' satisfaction rates and which factors predict favourable outcomes through the aggregate analysis of N-of-1 trials.

METHODS

Eighty-one outpatients with CC or with irritable bowel syndrome with constipation underwent N-of-1 trials with at least a one-month cycle of effective treatment. Three primary endpoints (satisfaction with therapy, improvement after treatment and an extended satisfaction criterion including both endpoints) were adopted to define satisfaction with therapy. Dyssynergia, resting anal pressure, colonic transit time and somatisation were assessed. The Patient Assessment of Constipation-Symptoms (PAC-SYM) questionnaire and its Modified version (M-PAC-SYM) measured constipation severity. Straining at defecation, stool frequency and form were daily recorded. K statistics for agreement and logistic regression were used at statistical analysis.

RESULTS

Satisfaction with therapy was not achieved by 43% of patients, who had a significantly lower Body Mass Index (BMI) and more severe constipation at baseline. Only the change in constipation severity according to M-PAC-SYM remained significantly associated with satisfaction with therapy (OR = 4.3; P < 0.001) at multivariate analysis.

CONCLUSIONS

Satisfaction with therapy is often an unmet need for patients with CC or with irritable bowel syndrome with constipation. Lower BMI and more severe constipation are associated with worse outcome. Changes in M-PAC-SYM reflect satisfaction with therapy. ClinicalTrials.gov no. NCT02813616.

Effects of Alfuzosin, an α1-Adrenergic Antagonist, on Anal Pressures and Bowel Habits in Women With and Without Defecatory Disorders

BACKGROUND & AIMS

Some patients with defecatory disorders (DD) have high anal pressures that may impede rectal evacuation. Alpha-1 adrenoreceptors mediate as much as 50% of anal resting pressure in humans. We performed a randomized, placebo-controlled study of the effects of alfuzosin, an alpha1-adrenergic receptor antagonist, on anal pressures alone in healthy women and also on bowel symptoms in women with DD.

METHODS

In a double-blind study performed from March 2013 through March 2017, anal pressures were evaluated before and after 36 women with DD (constipation for at least 1 year) and 36 healthy women (controls) were randomly assigned (1:1) to groups given oral alfuzosin (2.5 mg immediate release) or placebo. Thereafter, patients were randomly assigned (1:1) to groups given oral alfuzosin (10 mg extended release) or placebo each day for 2 weeks. Participants kept daily diaries of bowel symptoms for 2 weeks before (baseline) and during administration of the test articles (treatment). Weekly questionnaires recorded the overall severity of constipation symptoms, bloating, abdominal pain, nausea, and vomiting; overall satisfaction with treatment of constipation was evaluated at weeks 2 and 4. The primary endpoint was the change in the number of spontaneous (SBMs) and complete SBMs (CSBMs) between the treatment and baseline periods. We evaluated relationships between stool form, passage, and complete evacuation.

RESULTS

Alfuzosin reduced anal resting pressure by 32 ± 3 mm Hg versus 16 ± 3 mm Hg for placebo (P = .0001) and anal pressure during evacuation by 26 ± 3 mm Hg versus 16 ± 3 mm Hg for placebo, (P = .03). However, alfuzosin did not significantly increase the rectoanal gradient, SBMs or CSBMs compared with placebo. Both formulations of alfuzosin were well tolerated. Hard stools and the ease of passage during defecation accounted for 72% and 76% of the variance in the satisfaction after defecation, respectively, during baseline and treatment periods.

CONCLUSIONS

In a randomized trial, alfuzosin reduced anal pressure at rest and during simulated evacuation in healthy and constipated women, compared with placebo, but did not improve bowel symptoms in constipated women. This could be because the drug does not improve stool form or dyssynergia, which also contribute to DD. ClinicalTrials.gov number, NCT 01834729.

Functional anal canal length measurement using high-resolution anorectal manometry to investigate anal sphincter dysfunction in patients with fecal incontinence or constipation

BACKGROUND

Using high-resolution anorectal manometry, we aimed to evaluate the: (a) optimal threshold to measure functional anal canal length (FACL) with intra- and inter-observer variability; (b) relationship between abnormal FACL and other phenotypic findings; and (c) utility of FACL measurement to discriminate between healthy volunteers (HV) and patients with fecal incontinence (FI) or chronic constipation (CC).

METHODS

Consecutive patients referred for investigation of FI or CC in isolation were included. FACL was calculated at 5, 10, 20, 30, and 50 mm Hg above rectal pressure. 5th-95th percentile in HV defined limits of normality.

KEY RESULTS

FACL was analyzed in 192 patients with FI (154 females), 204 patients with CC (175 females), and 134 HV (101 females). The optimal threshold for measurement of FACL was 20 mm Hg. Using this threshold, observer reproducibility was very high (ICC 0.99, P < 0.0001). FACL was shorter in females with FI and longer in females with CC compared to HV (2.3 vs 2.9 cm; and 3.4 cm vs 2.9 cm; both P < 0.0001). Twenty percent of females and 13% males with FI had a short FACL, associated with older age, anal hypotonia or hypocontractility, and a atrophic internal anal sphincter. However, abnormal FACL in isolation was only found in 1/190 FI (0.5%) and 2/201 CC (1%) patients; all other patients had other abnormal manometric findings.

CONCLUSIONS AND INFERENCES

Considering overlap with other routinely evaluated manometric parameters, FACL measurement does not provide additional information in the diagnostic assessment of FI or CC.

Refractory Constipation: What is the Clinician to Do?

Most clinicians will agree that chronic constipation is characterized by abnormal bowel movement consistency and/or frequency plus or minus evacuation symptoms, but patient perception of constipation varies widely and includes symptoms that may or may not meet official defining criteria. Although intermittent constipation is extremely common, only a small minority of patients seek care for their symptoms. Among these patients, dissatisfaction with the currently available laxative options is not uncommon, and many patients will require specialized care for severe or refractory symptoms-especially those with abdominal pain, irritable bowel syndrome overlap, bloating or distention, and psychological comorbidities. This review outlines a physiological assessment of the patient with refractory constipation, exploring treatment options among patients with slow transit, rectal evacuation disorders, and normal transit. In addition, we explore nonlaxative approaches to normal-transit patients bothered by ongoing symptoms, with an emphasis on the biopsychosocial model of functional gastrointestinal disease and treatment of visceral hypersensitivity using neuromodulators. Finally, we propose a comprehensive evaluation algorithm for the management of patients with refractory slow-transit constipation considering surgery and examine surgical options including colectomy and cecostomy using an antegrade continent enema.

Expert consensus document: Advances in the evaluation of anorectal function

Faecal incontinence and evacuation disorders are common, impair quality of life and incur substantial economic costs worldwide. As symptoms alone are poor predictors of underlying pathophysiology and aetiology, diagnostic tests of anorectal function could facilitate patient management in those cases that are refractory to conservative therapies. In the past decade, several major technological advances have improved our understanding of anorectal structure, coordination and sensorimotor function. This Consensus Statement provides the reader with an appraisal of the current indications, study performance characteristics, clinical utility, strengths and limitations of the most widely available tests of anorectal structure (ultrasonography and MRI) and function (anorectal manometry, neurophysiological investigations, rectal distension techniques and tests of evacuation, including defecography). Additionally, this article provides our consensus on the clinical relevance of these tests.

High-Resolution Anorectal Manometry - New Insights in the Diagnostic Assessment of Functional Anorectal Disorders

Functional anorectal disorders such as faecal incontinence (FI), functional anorectal pain, and functional defecation disorders (FDD) are highly prevalent and represent a high socioeconomic burden. Several tests of anorectal function exist in this setting; however, high-resolution anorectal manometry (HR-ARM) is a new tool that depicts pressure all along the anal canal and can assess rectoanal coordination. HR-ARM is used in the diagnosis of FI and especially FDD although data in health is still sparse, and pressure phenomena seen during simulated defecation, such as dyssynergia, are highly prevalent in health.

The assessment and management of defecatory dysfunction: a critical appraisal

PURPOSE OF REVIEW

To summarize the advances in diagnostic modalities and management options for defecatory dysfunction and highlight the areas in need of further research.

RECENT FINDINGS

The diagnostic utility of high-resolution anorectal manometry (ARM), which has emerged as a promising tool for the diagnosis of defecatory dysfunction, appears to be questionable in differentiating disease from normal physiology. There also seems to be discrepancy between results of various tests of anorectal function in the diagnosis of defecatory dysfunction. New revisions in diagnostic criteria for defecatory dysfunction by Rome IV consortium, may enhance its diagnostic yield. Biofeedback remains to be the most effective evidence-based treatment option for patients with defecatory dysfunction. Anorectal pressure profile cannot predict or mediate the success of biofeedback. Biofeedback may improve the symptoms through central effects.

SUMMARY

Despite the advances in the ARM and defecography techniques, no one test has been able to be considered as the 'gold standard' for diagnosis of defecatory dysfunction. The mechanism of action of biofeedback in defecatory dysfunction remains poorly understood.

Anorectal manometry: Should it be performed in a seated position?

BACKGROUND

Anorectal manometry (ARM) is typically preformed in a lateral position. This non-physiological testing position has produced an unexpected negative rectoanal pressure gradient (RAPG, i.e. difference between rectal and anal pressure) with normal defecation. This study was designed (i) to study differences in ARM parameters between water-perfused and solid-state sensors and between lateral and seated positions and (ii) to investigate the roles of ARM parameters in predicting balloon expulsion.

METHODS

ARM was performed in 18 healthy volunteers (HV) and 60 patients with functional constipation (FC) under three randomized conditions: water-perfused in lateral position, solid-state in lateral position, and solid-state in seated position, followed by a balloon expulsion test in seated position.

KEY RESULTS

i) Under the same lateral position, solid-state sensors produced higher rectal resting pressure and RAPG than water-perfused sensors. ii) Using the solid-state sensors, ARM in the seated position revealed higher resting rectal pressure (34.9 vs 10.9 mmHg in HV, 30.9 vs 10.6 mmHg in FC, both P<.001) and higher RAPG (22.6 vs -6.2 mmHg in HV, 17.1 vs -8.1 mmHg in FC, both P<.001) than the lateral position. iii) When ARM was performed using solid-state sensors in seated position, RAPG was predictive of balloon expulsion; using 10 mmHg as a threshold, RAPG could predict balloon expulsion with specificity of 82% and sensitivity 77%.

CONCLUSIONS AND INFERENCE

ARM performed in a seated position using solid-state sensors seems more accurate in assessing rectal pressure, and the RAPG measured under these conditions is predictive of balloon expulsion in FC patients.