Solid-state vs water-perfused catheters to measure colonic high-amplitude propagating contractions

Efficacy of anal botulinum toxin injection in children with functional constipation

OBJECTIVES

Functional constipation (FC) is a common diagnosis in the pediatric age group. In addition to laxative regimens and behavioral interventions, some have reported the use of anal botulinum toxin (BTX) injections to treat FC, with limited data regarding its efficacy.

METHODS

This is a retrospective, multicenter study including patients who received BTX for FC refractory to medical therapy. Demographic data, results of anorectal manometry, and BTX data (number of sessions, dose, and side effects) were collected. Patients were divided into three groups based on the indication for BTX: group 1 (FC with FI [fecal incontinence]), group 2 (FC without FI), and group 3 (FI alone). Response to therapy was assessed for whole cohort and for each group based on improvement in weekly frequency of BM (bowel movements) to 3 or more per week and/or resolution of FI. We also compared the response to therapy to the parental and provider report.

RESULTS

A total of 63 patients were included in the study. Median age was 6.4 years and 32 (51%) were female. The median dose of BTX was 100 units, and most patients (55/63) received a single BTX injection. Medical therapy was continued after BTX injections in most patients (60/63 or 95%). After BTX, the frequency of BM increased to >3/week in 29/56 (52%) and FI improved in 8/47 (17%) for the whole cohort. We observed a response rate of 10% in group 1, 50% in group 2 and 14% in group 3. No factors (age, gender, anal resting pressure) were associated with BTX response except for prolonged time of therapy before BTX and shorter median follow up after BTX. Parents/primary provider reported improvement in 44/63 (70%) after BTX, which was significantly higher than the actual observed response to therapy (70% vs. 21%, p = 0.003, kappa = 0.202). We found no association between response to BTX and presence of developmental delay and/or behavioral disorders (p = 0.531). Side effects were minimal and noted in seven (11%) patients, mainly FI. No factors were associated with the development of side effects.

CONCLUSIONS

Anal BTX injections improved BM frequency with minimal effect on FI with an overall symptom resolution in 21% of patients. BTX does not seem to have a notable effect in patients with FC and developmental delay and/or behavioral disorders. Provider and parental reported success were significantly higher than the actual observed response.

An expert's guide to classical manometric patterns seen in high-resolution colonic manometry

INTRODUCTION

High-resolution colonic manometry is a research and diagnostic tool used to evaluate colonic motility. Used in health it helps us understand normal colonic motility and the colonic response to physiological stimuli such as meal, as well as chemical (laxatives) and mechanical (distension) stimuli. In pediatric and adult patients with suspected colonic disorders, it can help to understand the abnormal colonic motility associated with the condition.

AREA COVERED

High-resolution manometric catheters contain multiple closely spaced sensors that detect intraluminal pressure changes and contractile force, which can be interpreted as contractile activity. This activity forms several distinctive motor patterns that help in understanding normal colonic physiology and provide insights into the potential pathophysiology underlying colonic disorders such as constipation. After a PubMed search of colonic high-resolution manometry studies, this review provides an overview of the characterized motor patterns, when they occur, how they are initiated, their clinical relevance, and their role, if any, in guiding therapeutic interventions.

EXPERT OPINION

High-resolution colonic manometry has identified motor patterns that were missed or mislabeled by low-resolution recordings. How best to use this information to guide treatment remains to be determined.

Testing in functional constipation-What's new and what works

BACKGROUND

Constipation is among the most common symptoms prompting a consultation with a paediatric gastroenterologist. While most patients will respond to lifestyle and dietary changes and conventional therapy, some may require diagnostic studies.

AIM

To review the diagnostics studies used to evaluate children with functional constipation.

MATERIALS AND METHODS

There is no evidence to support the routine use of abdominal X-rays in the evaluation of paediatric constipation. Colon transit by radiopaque markers (ROM) should be indicated when medical history does not match clinical findings, to guide colon manometry (CM) performance and to discriminate between faecal incontinence from functional constipation and non-retentive faecal incontinence. Colon scintigraphy may be useful as an alternative to ROM. Lumbar spine MRI may be indicated to evaluate for spinal abnormalities. The role of defecography has not been properly evaluated in children. Anorectal manometry in children is indicated primarily to evaluate anal resting pressure, presence and quality of the recto-anal inhibitory reflex and simulated defecation manoeuvres. The CM is indicated to guide surgical interventions after failing medical therapy.

CONCLUSIONS

The goal of these studies is to identify treatable causes of constipation. Most of these studies are designed to evaluate anatomy, transit and/or colon/rectum motility function and are primarily indicated in those who fail to respond to conventional therapy.

Clinical Utility of Ileal Motility in Children With Defecation Disorders and Children With Chronic Intestinal Pseudo-Obstruction

BACKGROUND

Little is known about ileal motility patterns and their utility in children. Here, we present our experience with children undergoing ileal manometry (IM).

METHODS

A retrospective review of children with ileostomy comparing IM between 2 groups: A [chronic intestinal pseudo-obstruction (CIPO)] and B (feasibility of ileostomy closure in children with defecation disorders). We also compared the IM findings with those from antroduodenal manometry (ADM), and evaluated the joint effect of age, sex, and study indication group on IM results.

RESULTS

A total of 27 children (median age 5.8 years old, range 0.5-16.74 years, 16 were female) were included (12 in group A and 15 in group B). There was no association between IM interpretation and sex; however younger age was associated with abnormal IM ( P = 0.021). We found a significantly higher proportion of patients with presence of phase III of the migrating motor complex (MMC) during fasting and normal postprandial response in group B than in group A ( P < 0.001). Logistic regression analysis revealed that only Group B was associated with normal IM ( P < 0.001). We found a moderate agreement for the presence of phase III MMC and postprandial response between IM and ADM (kappa = 0.698, P = 0.008 and kappa = 0.683, P = 0.009, respectively).

CONCLUSION

IM is abnormal in patients with CIPO and normal in patients with defecation disorders, suggesting that IM may be not needed for ostomy closure in those with defecation disorders. IM has a moderate agreement with ADM and could be used as a surrogate for small bowel motility.

Clinical utility of colonic low-amplitude propagating contractions in children with functional constipation

BACKGROUND

Colonic high-amplitude propagating contractions (HAPC) are generally accepted as a marker of neuromuscular integrity. Little is known about low-amplitude propagating contractions (LAPCs); we evaluated their clinical utility in children.

METHODS

Retrospective review of children with functional constipation undergoing low-resolution colon manometry (CM) recording HAPCs and LAPCs (physiologic or bisacodyl-induced) in three groups: constipation, antegrade colonic enemas (ACE), and ileostomy. Outcome (therapy response) was compared to LAPCs in all patients and within groups. We evaluated LAPCs as potentially representing failed HAPCs.

KEY RESULTS

A total of 445 patients were included (median age 9.0 years, 54% female), 73 had LAPCs. We found no association between LAPCs and outcome (all patients, p = 0.121), corroborated by logistic regression and excluding HAPCs. We found an association between physiologic LAPCs and outcome that disappears when excluding HAPCs or controlling with logistic regression. We found no association between outcome and bisacodyl-induced LAPCs or LAPC propagation. We found an association between LAPCs and outcome only in the constipation group that cancels with logistic regression and excluding HAPCs (p = 0.026, 0.062, and 0.243, respectively). We found a higher proportion of patients with LAPCs amongst those with absent or abnormally propagated (absent or partially propagated) HAPCs compared to those with fully propagated HAPCs (p = 0.001 and 0.004, respectively) suggesting LAPCs may represent failed HAPCs.

CONCLUSIONS/INFERENCES

LAPCs do not seem to have added clinical significance in pediatric functional constipation; CM interpretation could rely primarily on the presence of HAPCs. LAPCs may represent failed HAPCs. Larger studies are needed to further validate these findings.

Slow, deep breathing intervention improved symptoms and altered rectal sensitivity in patients with constipation-predominant irritable bowel syndrome

BACKGROUND AND AIM

Limited treatment options have been shown to alter the natural course of irritable bowel syndrome (IBS). Slow, deep breathing (SDB) is a common pain self-management intervention. This pilot study aimed to explore the impact of SDB on measures of autonomic and anorectal functions as well as patient-reported symptoms in constipation-predominant IBS (IBS-C).

METHODS

Eighty-five IBS-C patients were enrolled in this study and randomly assigned to the experimental group (Group A, n = 42) and the control group (Group B, n = 43). SDB was conducted at six breathing cycles per minute with an inhalation for 4 s and exhalation for 6 s at a ratio of 2:3 and repeated for 30 min during the intervention. All subjects underwent high-resolution anorectal manometry (HRAM) and completed the standardized IBS symptom severity system (IBS-SSS) questionnaire. Meanwhile, changes in stool consistency, weekly frequency of complete spontaneous bowel movements (CSBMs), and weekly frequency of spontaneous bowel movements (SBMs) were recorded. All IBS-C patients received electrocardiogram (ECG) recordings for heart rate variability (HRV) analysis at baseline, weeks 3, 6.

RESULTS

At baseline, no differences were found between Groups A and B. The IBS-SSS score and its five sub-scores of Group B patients were significantly higher at week 6 than those of Group A patients (all p < 0.001). Furthermore, compared with Group B patients, Group A patients had a significantly higher threshold volume for the first sensation (p < 0.001), desire to defecate (p = 0.017), and maximum tolerable volume (p = 0.018) at week 6 of the SDB treatment. We also noted significant improvements in stool consistency (p = 0.002), weekly SBM frequencies (p < 0.001), and weekly CSBM frequencies (p = 0.018) of Group A patients at week 6 when compared with Group B patients. Finally, the corrected high frequency (HF) of Group A patients was significantly higher than the HF of Group B patients at week 3 (p < 0.001) and at week 6 (p < 0.001). Likewise, patients in Group A had a significantly higher root mean square of the successive differences (RMSSD) than that of patients in Group B at week 3 (p < 0.001) and at week 6 (p < 0.001).

CONCLUSION

We found that a 6-week SDB intervention improved symptoms and altered rectal sensation in IBS-C patients. Moreover, SDB enhanced vagal activity. These findings suggest that the effect of SDB on IBS-C may be due to mechanisms involving autonomic responses.

Low-cost gastrointestinal manometry via silicone-liquid-metal pressure transducers resembling a quipu

The evaluation of the tone and contractile patterns of the gastrointestinal (GI) tract via manometry is essential for the diagnosis of GI motility disorders. However, manometry is expensive and relies on complex and bulky instrumentation. Here we report the development and performance of an inexpensive and easy-to-manufacture catheter-like device for capturing manometric data across the dynamic range observed in the human GI tract. The device, which we designed to resemble the quipu-knotted strings used by Andean civilizations for the capture and transmission of information-consists of knotted piezoresistive pressure sensors made by infusing a liquid metal (eutectic gallium-indium) through thin silicone tubing. By exploring a range of knotting configurations, we identified optimal design schemes that led to sensing performances comparable to those of commercial devices for GI manometry, as we show for the sensing of GI motility in multiple anatomic sites of the GI tract of anaesthetized pigs. Disposable and customizable piezoresistive catheters may broaden the use of GI manometry in low-resource settings.

Sleep Deficiency Is Associated With Exacerbation of Symptoms and Impairment of Anorectal and Autonomic Functions in Patients With Functional Constipation

Objective

Sleep deficiency (SD) is commonly seen in patients with functional constipation (FC). Our aim was to determine whether the presence of SD would influence symptoms, anorectal motility, sensation, and autonomic function in FC patients.

Materials and Methods

A total of 85 FC patients with SD and 193 FC patients without SD underwent high-resolution anorectal manometry. SD was assessed by using the Pittsburgh Sleep Quality Index (PSQI) score. Participants were required to fill in the entire questionnaires, including Patients' Constipation-symptoms, State-Trait Anxiety Inventory, and Hamilton Depression Scale. Autonomic dysfunction was studied by recording the heart rate variability. Multiple logistic regression was performed to explore the potential risk factors for anorectal function.

Results

Functional constipation patients with SD had a higher total score of constipation symptom (P < 0.001), in comparison with those without SD. FC patients with SD demonstrated significantly lower threshold volume for first sensation (P < 0.001) and urge (P < 0.001), as compared to those without SD. The PSQI score positively correlated with constipation symptom total score (P < 0.001), and negatively correlated with threshold volume for first sensation (P < 0.001) and urge (P < 0.001). FC patients with SD had a reduced vagal activity (P = 0.016) and a higher sympathetic activity as compared to those without SD (P = 0.003). Multivariate logistic regression revealed that SD, anxiety and depression were independent risk factors for anorectal function, with SD exhibiting the highest degree of association with first sensation (OR: 4.235).

Conclusion

Sleep deficiency is associated with worse constipation related symptoms, altered anorectal function and perception, and impaired autonomic function in FC patients.

A Guide to Establishing a Pediatric Neurogastroenterology and Motility Program

ABSTRACT

The purpose of this document is to provide guidance for establishing a pediatric neurogastroenterology and motility (PNGM) program, including considerations for personnel, equipment, and physical space requirements, and business planning, from members of the neurogastroenterology and motility (NGM) Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) who have developed PNGM programs at various institutions. A business plan defining the needs for required personnel, dedicated physical space, procedures, clinical care, and equipment storage is a prerequisite. Thoughtful logistical planning should address provider schedules, clinical visits, procedure coordination, and prior authorization processes. A business-plan outlining equipment purchase with projected costs, revenue generation, and goals for future growth is desirable for obtaining institutional support, which is imperative to building a successful PNGM program.

Simulating the Hydrodynamic Conditions of the Human Ascending Colon: A Digital Twin of the Dynamic Colon Model

The performance of solid oral dosage forms targeting the colon is typically evaluated using standardised pharmacopeial dissolution apparatuses. However, these fail to replicate colonic hydrodynamics. This study develops a digital twin of the Dynamic Colon Model; a physiologically representative in vitro model of the human proximal colon. Magnetic resonance imaging of the Dynamic Colon Model verified that the digital twin robustly replicated flow patterns under different physiological conditions (media viscosity, volume, and peristaltic wave speed). During local contractile activity, antegrade flows of 0.06-0.78 cm s^-1 and backflows of -2.16--0.21 cm s^-1 were measured. Mean wall shear rates were strongly time and viscosity dependent although peaks were measured between 3.05-10.12 s^-1 and 5.11-20.34 s^-1 in the Dynamic Colon Model and its digital twin respectively, comparable to previous estimates of the USPII with paddle speeds of 25 and 50 rpm. It is recommended that viscosity and shear rates are considered when designing future dissolution test methodologies for colon-targeted formulations. In the USPII, paddle speeds >50 rpm may not recreate physiologically relevant shear rates. These findings demonstrate how the combination of biorelevant in vitro and in silico models can provide new insights for dissolution testing beyond established pharmacopeial methods.

Analysis of Intestinal Movements with Spatiotemporal Maps: Beyond Anatomy and Physiology

Over 150 years ago, methods for quantitative analysis of gastrointestinal motor patterns first appeared. Graphic representations of physiological variables were recorded with the kymograph after the mid-1800s. Changes in force or length of intestinal muscles could be quantified, however most recordings were limited to a single point along the digestive tract.In parallel, photography and cinematography with X-Rays visualised changes in intestinal shape, but were hard to quantify. More recently, the ability to record physiological events at many sites along the gut in combination with computer processing allowed construction of spatiotemporal maps. These included diameter maps (DMaps), constructed from video recordings of intestinal movements and pressure maps (PMaps), constructed using data from high-resolution manometry catheters. Combining different kinds of spatiotemporal maps revealed additional details about gut wall status, including compliance, which relates forces to changes in length. Plotting compliance values along the intestine enabled combined DPMaps to be constructed, which can distinguish active contractions and relaxations from passive changes. From combinations of spatiotemporal maps, it is possible to deduce the role of enteric circuits and pacemaker cells in the generation of complex motor patterns. Development and application of spatiotemporal methods to normal and abnormal motor patterns in animals and humans is ongoing, with further technical improvements arising from their combination with impedance manometry, magnetic resonance imaging, electrophysiology, and ultrasonography.

The cyclic motor patterns in the human colon

BACKGROUND

High-resolution colonic manometry gives an unprecedented window into motor patterns of the human colon. Our objective was to characterize motor activities throughout the entire colon that possessed persistent rhythmicity and spanning at least 5 cm.

METHODS

High-resolution colonic manometry using an 84-channel water-perfused catheter was performed in 19 healthy volunteers. Rhythmic activity was assessed during baseline, proximal balloon distention, meal, and bisacodyl administration.

KEY RESULTS

Throughout the entire colon, a cyclic motor pattern occurred either in isolation or following a high-amplitude propagating pressure wave (HAPW), consisting of clusters of pressure waves at a frequency centered on 11-13 cycles/min, unrelated to breathing. The cluster duration was 1-6 minutes; the pressure waves traveled for 8-27 cm, lasting 5-8 seconds. The clusters itself could be rhythmic at 0.5-2 cpm. The propagation direction of the individual pressure waves was mixed with >50% occurring simultaneous. This high-frequency cyclic motor pattern co-existed with the well-known low-frequency cyclic motor pattern centered on 3-4 cpm. In the rectum, the low-frequency cyclic motor pattern dominated, propagating predominantly in retrograde direction. Proximal balloon distention, a meal and bisacodyl administration induced HAPWs followed by cyclic motor patterns.

CONCLUSIONS AND INFERENCES

Within cyclic motor patterns, retrograde propagating, low-frequency pressure waves dominate in the rectum, likely keeping the rectum empty; and mixed propagation, high-frequency pressure waves dominate in the colon, likely promoting absorption and storage, hence contributing to continence. Propagation and frequency characteristics are likely determined by network properties of the interstitial cells of Cajal.

High-resolution colonic manometry and its clinical application in patients with colonic dysmotility: A review

The detailed process and mechanism of colonic motility are still unclear, and colonic motility disorders are associated with numerous clinical diseases. Colonic manometry is considered to the most direct means of evaluating colonic peristalsis. Colonic manometry has been studied for more than 30 years; however, the long duration of the examination, high risk of catheterization, huge amount of real-time data, strict catheter sterilization, and high cost of disposable equipment restrict its wide application in clinical practice. Recently, high-resolution colonic manometry (HRCM) has rapidly developed into a major technique for obtaining more effective information involved in the physiology and/or pathophysiology of colonic contractile activity in colonic dysmotility patients. This review focuses on colonic motility, manometry, operation, and motor patterns, and the clinical application of HRCM. Furthermore, the limitations, future directions, and potential usefulness of HRCM in the evaluation of clinical treatment effects are also discussed.

Constipation: Beyond the Old Paradigms

Constipation is a common problem in children. Although most children respond to conventional treatment, symptoms persist in a minority. For children with refractory constipation, anorectal and colonic manometry testing can identify a rectal evacuation disorder or colonic motility disorder and guide subsequent management. Novel medications used in adults with constipation are beginning to be used in children, with promising results. Biofeedback therapy and anal sphincter botulinum toxin injection can be considered for children with a rectal evacuation disorder. Surgical management of constipation includes the use of antegrade continence enemas, sacral nerve stimulation, and colonic resection.

Characterization of Simultaneous Pressure Waves as Biomarkers for Colonic Motility Assessed by High-Resolution Colonic Manometry

Simultaneous pressure waves (SPWs) in manometry recordings of the human colon have been associated with gas expulsion. Our hypothesis was that the SPW might be a critical component of most colonic motor functions, and hence might act as a biomarker for healthy colon motility. To that end, we performed high-resolution colonic manometry (HRCM), for the first time using an 84-sensor (1 cm spaced) water-perfused catheter, in 17 healthy volunteers. Intraluminal pressure patterns were recorded during baseline, proximal and rectal balloon distention, after a meal and following proximal and rectal luminal bisacodyl administration. Quantification was performed using software, based on Image J, developed during this study. Gas expulsion was always associated with SPWs, furthermore, SPWs were associated with water or balloon expulsion. SPWs were prominently emerging at the termination of proximal high amplitude propagating pressure waves (HAPWs); we termed this motor pattern HAPW-SPWs; hence, SPWs were often not a pan-colonic event. SPWs and HAPW-SPWs were observed at baseline with SPW amplitudes of 12.0 ± 8.5 mmHg and 20.2 ± 7.2 mmHg respectively. The SPW occurrence and amplitude significantly increased in response to meal, balloon distention and luminal bisacodyl, associated with 50.3% anal sphincter relaxation at baseline, which significantly increased to 59.0% after a meal, and 69.1% after bisacodyl. Often, full relaxation was achieved. The SPWs associated with gas expulsion had a significantly higher amplitude compared to SPWs without gas expulsion. SPWs could be seen to consist of clusters of high frequency pressure waves, likely associated with a cluster of fast propagating, circular muscle contractions. SPWs were occasionally observed in a highly rhythmic pattern at 1.8 ± 1.2 cycles/min. Unlike HAPWs, the SPWs did not obliterate haustral boundaries thereby explaining how gas can be expelled while solid content can remain restrained by the haustral boundaries. In conclusion, the SPW may become a biomarker for normal gas transit, the gastrocolonic reflex and extrinsic neural reflexes. The SPW assessment reveals coordination of activities in the colon, rectum and anal sphincters. SPWs may become of diagnostic value in patients with colonic dysmotility.

Motility of the left colon in children and adolescents with functional constpation; a retrospective comparison between solid-state and water-perfused colonic manometry

BACKGROUND

Using water-perfused (WP) high-resolution manometry, we recently demonstrated that children with functional constipation (FC) lacked the postprandial increase in distal colonic cyclic motor patterns that was observed in healthy adults. Our aim was to determine if similar results could be detected using a solid-state (SS) manometry catheter.

METHODS

We performed a retrospective analysis of 19 children with FC (median age 11.1 years, 58% male) who underwent colonic manometry with a SS catheter (36 sensors, 3 cm apart). Data were compared with previously published data using a WP catheter (36 sensors, 1.5 cm apart) recorded from 18 children with FC (median age 15 years; 28% male).

KEY RESULTS

The cyclic motor patterns recorded by the SS catheter did not differ from those previously recorded by the WP catheter. There was no detected increase in this activity in response to the meal in either group. Long-single motor patterns were recorded in most patients (n = 16, 84%) with the SS catheter. The number of these events did not differ from the WP recordings. In the SS data, HAPCs were observed in 4 children prior to the meal, in 5 after the meal. This did not differ significantly from the WP data.

CONCLUSIONS & INFERENCES

These data recorded by SS manometry did not differ from WP manometry data. Regardless of the catheter used, both studies revealed an abnormal colonic response to a meal, indicating a pathology which is not related to the catheter used to record these data.

High-resolution anorectal manometry: A comparison of solid-state and water-perfused catheters

BACKGROUND

Anorectal manometry is the most commonly performed investigation for assessment of anorectal dysfunction. Findings from previous studies comparing water-perfused (WP) and solid-state (SS) techniques in the anorectum are conflicting. We compared anal sphincter pressure at rest and during dynamic maneuvers (squeezing and coughing) in healthy volunteers using SS and WP high-resolution anorectal manometry (HR-ARM) employing equivalent catheter configurations, a standardized protocol, and identical data acquisition and analysis software.

METHODS

Sixty healthy volunteers (40F; median age: 40; range: 18-74) underwent WP and SS HR-ARM in randomized order. Anal resting pressure, and squeeze and cough increments were measured. Median pressure and 5th and 95th percentiles were calculated for each maneuver and compared using Wilcoxon signed-rank test. Bland and Altman plots were used to assess agreement between the systems. The impact of gender and parity was also explored.

KEY RESULTS

Anal sphincter pressure measurements during squeeze (P<.001) and cough (P<.001) were significantly higher using SS HR-ARM than WP HR-ARM. No differences were seen at rest between the two types of catheter (nulliparous: P=.304; parous: P=.390; males: P=.167). Normal ranges for SS and WP manometry from this small group of healthy volunteers are presented.

CONCLUSIONS & INFERENCES

Greater sensitivity to rapid pressure change is one of the advantages associated with SS HR-ARM. This is reflected in the differences observed during dynamic maneuvers performed during this study. Catheter type should be taken into consideration when selecting normal ranges for comparison to disease states.

Segmental colonic dilation is associated with premature termination of high-amplitude propagating contractions in children with intractable functional constipation

BACKGROUND

Colonic dilation is common in children with intractable functional constipation (FC). Our aim was to describe the association between segmental colonic dilation and colonic dysmotility in children with FC.

METHODS

We performed a retrospective study on 30 children with intractable FC (according to the Rome III criteria) who had undergone colonic manometry and contrast enema within a 12-month time period. Colonic diameter was measured at 5 cm intervals from the anal verge up to the splenic flexure. Moreover, the distance between the lateral margins of the pedicles of vertebra L2 was measured to provide a ratio (colonic diameter or length/distance between the lateral margins; "standardized colon size" [SCS]). All manometry recordings were visually inspected for the presence of high-amplitude propagating contractions (HAPCs); a parameter for colonic motility integrity. The intracolonic location of the manometry catheter sensors was assessed using an abdominal X-ray.

KEY RESULTS

Colonic segments with HAPCs had a significantly smaller median diameter than colonic segments without HAPCs (4.08 cm vs 5.48 cm, P<.001; SCS 1.14 vs 1.66, P=.001). Children with prematurely terminating HAPCs had significantly larger SCS ratios for colonic diameter than children with fully propagating HAPCs (P=.008). SCS ratios for the length of the rectosigmoid and the descending colon and the SCS ratio for sigmoid colon diameter were significantly larger in children with FC compared to a previously described normative population (P<.0001, P<.0001 and P=.0007 respectively).

CONCLUSIONS & INFERENCES

Segmental colonic dilation was associated with prematurely terminating HAPCs and may be a useful indicator of colonic dysmotility.

Intraluminal pressure patterns in the human colon assessed by high-resolution manometry

Assessment of colonic motor dysfunction is rarely done because of inadequate methodology and lack of knowledge about normal motor patterns. Here we report on elucidation of intraluminal pressure patterns using High Resolution Colonic Manometry during a baseline period and in response to a meal, in 15 patients with constipation, chronically dependent on laxatives, 5 healthy volunteers and 9 patients with minor, transient, IBS-like symptoms but no sign of constipation. Simultaneous pressure waves (SPWs) were the most prominent propulsive motor pattern, associated with gas expulsion and anal sphincter relaxation, inferred to be associated with fast propagating contractions. Isolated pressure transients occurred in most sensors, ranging in amplitude from 5–230 mmHg. Rhythmic haustral boundary pressure transients occurred at sensors about 4–5 cm apart. Synchronized haustral pressure waves, covering 3–5 cm of the colon occurred to create a characteristic intrahaustral cyclic motor pattern at 3–6 cycles/min, propagating in mixed direction. This activity abruptly alternated with erratic patterns resembling the segmentation motor pattern of the small intestine. High amplitude propagating pressure waves (HAPWs) were too rare to contribute to function assessment in most subjects. Most patients, dependent on laxatives for defecation, were able to generate normal motor patterns in response to a meal.

Transanal Irrigation in the Treatment of Children With Intractable Functional Constipation

OBJECTIVES

The aim of the study was to assess the treatment efficacy of transanal irrigation and parental satisfaction in children with intractable functional constipation (FC) treated with Peristeen.

METHODS

Cross-sectional survey study among parents of children (age 0-18 years) treated with Peristeen for FC (based on the Rome III criteria). Anonymous questionnaires were sent out to parents via mail, these consisted of 25 self-developed, multiple-choice questions regarding the use of Peristeen, current gastrointestinal symptoms, adverse effects of Peristeen, concomitant medication use, and parental satisfaction.

RESULTS

Out of 91 invited families, 67 (74%) returned the questionnaire. In total, 84% of patients experienced fecal incontinence prior to treatment. Out of all children who still used Peristeen at the time of survey (n = 49), fecal incontinence had resolved completely in 41%, 12% experienced occasional episodes of fecal incontinence (<1 episode per week) and the remaining 47% still experienced episodes of fecal incontinence regularly (≥1 time per week). A total of 28 children (42%) experienced pain during rectal irrigation, especially during insertion of the catheter, inflating the balloon, or during irrigation. Overall, 86% of the parents were satisfied with the result of transanal irrigation and 67% reported that they would continue using transanal irrigation for the treatment of their child's symptoms.

CONCLUSIONS

Transanal irrigation may be effective in the treatment of children with FC and renders a high parental satisfaction. Future prospective studies, preferably RCTs, are necessary to further evaluate this treatment option.

An ANMS-NASPGHAN consensus document on anorectal and colonic manometry in children

BACKGROUND

Over the last few years, the study of the colon and anorectal function has experienced great technical advances that have facilitated the performance of the tests and have allowed a more detailed characterization of reflexes and motor patterns. As a result, we have achieved a much better understanding of the pathophysiology of children with defecation problems. Anorectal and colonic manometry are now commonly used in all major pediatric referral centers as diagnostic tools and to guide the management of children with intractable constipation and fecal incontinence, particularly when a surgical intervention is being considered.

PURPOSE

This review highlights some of the recent advances in pediatric colon and anorectal motility testing including indications and preparation for the studies, and how to perform and interpret the tests. This update has been endorsed by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN).

Sequential incremental doses of bisacodyl increase the diagnostic accuracy of colonic manometry

BACKGROUND

Colonic manometry is the standard diagnostic modality for evaluating colonic motility in children. Intraluminal bisacodyl is routinely used to trigger high-amplitude propagating contractions (HAPCs), a feature of normal colonic motility. Usually, only a single dose (0.2 mg/kg) is suggested. We retrospectively explored whether the use of an additional higher (0.4 mg/kg) dose of bisacodyl increases the yield of colonic manometry.

METHODS

In 103 children (median age: 8.8 years, range 3.2-15.7 years) with a diagnosis of slow transit constipation, colonic motility was recorded for 1 h before and 1 h after each of two incremental doses of bisacodyl (low, L, dose: 0.2 mg/kg, max 10 mg; high, H, dose: 0.4 mg/kg, max 20 mg) and the characteristics of HAPCs analyzed.

KEY RESULTS

High-amplitude propagating contractions were seen in 85 children. H dose significantly increased the proportion of patients with fully propagated HAPCs (H dose: 57/103 [55%], L dose: 27/103 [26%], p < 0.001), paralleling the significant decrease in the proportion with partially propagated HAPCs (H dose: 29/103 [28%], L dose: 47/103 [46%], p < 0.01). Mean HAPC number significantly increased throughout the colon at H compared to L dose (7.2 ± 5.05 vs 5.6 ± 5.1, p < 0.05). Finally, the proportion of patients with normal pressure wave morphology of HAPCs significantly increased with higher dose (H dose: 55/85 [65%], L dose: 27/85 [32%], p < 0.001).

CONCLUSIONS & INTERFERENCES

An additional higher dose of bisacodyl during colonic manometry improves colonic neuromuscular function suggesting its use might improve interpretation and decision making in children with slow transit constipation.

Childhood constipation: finally something is moving!

Recent developments in the evaluation and treatment of childhood constipation are likely to influence the way we deal with pediatric defecation disorders in the near future. Innovations in both colonic and anorectal manometry are leading to novel insights into functional defecation disorders in children. Promising results have been achieved with innovative therapies such as electrical stimulation and new drugs with targets that differ from conventional pharmacological treatments. Also, new surgical approaches, guided by manometric findings, have led to improvement in patient outcome. Finally, utilization of non-pharmacological interventions such as fiber and probiotics has been a field of particular interest in recent years. The aim of this article is to provide an update on these and other novel diagnostic and therapeutic tools related to childhood constipation.

Characterizing colonic motility in children with chronic intractable constipation: a look beyond high-amplitude propagating sequences

BACKGROUND

Children with chronic intractable constipation experience severe and long-lasting symptoms, which respond poorly to conventional therapeutic strategies. Detailed characterization of colonic motor patterns in such children has not yet been obtained.

METHODS

In 18 children with chronic intractable constipation, a high-resolution water-perfused manometry catheter (36 sensors at 1.5-cm intervals) was colonoscopically placed with the tip at the distal transverse colon. Colonic motor patterns were recorded for 2 h prior to and after a meal and then after colonic infusion of bisacodyl. These data were compared with previously published colonic manometry data from 12 healthy adult controls and 14 adults with slow-transit constipation.

KEY RESULTS

The postprandial number of the retrograde cyclic propagating motor pattern was significantly reduced in these children compared with healthy adults (children, 3.1 ± 4.7/h vs healthy adults, 34.7 ± 45.8/h; p < 0.0001) but not constipated adults (4.5 ± 5.6/h; p = 0.9). The number of preprandial long-single motor patterns was significantly higher (p = 0.003) in children (8.0 ± 13.2/h) than in healthy adults (0.4 ± 0.9/h) and in constipated adults (0.4 ± 0.7/h). Postprandial high-amplitude propagating sequences (HAPSs) were rarely observed in children (2/18), but HAPS could be induced by bisacodyl in 16 of 18 children.

CONCLUSIONS & INFERENCES

Children with chronic intractable constipation show a similar impaired postprandial colonic response to that seen in adults with slow-transit constipation. Children may have attenuated extrinsic parasympathetic inputs to the colon associated with an increased incidence of spontaneous long-single motor patterns.

Colon high-resolution manometry: using pressure topography plots to evaluate pediatric colon motility

OBJECTIVES

Colon manometry is usually performed using the 8-pressure sensor water-perfused manometry system. High-resolution manometry (HRM), using closely spaced solid-state pressure recording sensors, provides more detailed information of gut luminal pressure changes, and, by displaying the HRM data as a pressure topography plot (PTP), helps with data interpretation. Our aim was to compare the colon and rectal luminal pressure data obtained using 8 pressure sensors and displayed as conventional line plot (CLP) with data obtained using a custom-made solid state manometry catheter with 36 pressure recording sensors and displayed as PTP.

METHODS

We evaluated colon manometry patterns during fasting, response to meal, and bisacodyl stimulation in 10 patients with constipation and stool expulsion disorders. The data from 8 pressure sensors were displayed as CLP and data from 36 pressure sensors as PTP. Two gastroenterologists independently interpreted these studies. We calculated variability in interpreting colon, rectal, and anal manometry data.

RESULTS

Intermode, interobserver, and intraobserver reliability were good to excellent for recognizing colon contraction patterns when data are displayed as PTP compared with when displayed as CLP, whereas the reliability for recognizing anal contractions were poor to excellent.

CONCLUSIONS

Colonic and anal manometry patterns are easily recognized when HRM data are expressed as PTP. Obtaining information of colonic luminal pressure changes with rectum and anal pressure changes using HRM can help better understand the pathophysiology of pediatric constipation and stool expulsion disorders.

Assessment and in vitro experiment of artificial anal sphincter system based on rebuilding the rectal sensation function

In this paper, a novel artificial anal sphincter (AAS) system based on rebuilding the rectal sensation function is proposed to treat human fecal incontinence. The executive mechanism of the traditional AAS system was redesigned and integrated for a simpler structure and better durability. The novel executive mechanism uses a sandwich structure to simulate the basic function of the natural human anal sphincter. To rebuild the lost rectal sensation function caused by fecal incontinence, we propose a novel method for rebuilding the rectal sensation function based on an Optimal Wavelet Packet Basis (OWPB) using the Davies-Bouldin (DB) index and a support vector machine (SVM). OWPB using a DB index is used for feature vector extraction, while a SVM is adopted for pattern recognition.Furthermore, an in vitro experiment with the AAS system based on rectal sensation function rebuilding was carried out. Experimental results indicate that the novel executive mechanism can simulate the basic function of the natural human anal sphincter, and the proposed method is quite effective for rebuilding rectal sensation in patients.

Novel techniques to study colonic motor function in children

Colonic motility is an essential component of normal colonic physiology and it controls essential bodily functions such as stool propulsion, storage, and expulsion. Disordered colonic motility may present with constipation or diarrhea as well as associated symptoms such as bloating, gas, pain, incontinence, and others. In order to assess colonic motor function, practitioners may use studies that either investigate transit time or that evaluate peristaltic activity. Transit time is the result of both the effectiveness of propulsive pressures and the physical characteristics of the stools. Its measurement allows one to quantify the extent and severity of the colonic dysfunction and permits the assessment of response to therapy. Various methods exist to investigate colon transit time and motility. In this review, we will focus on newer techniques for these investigations, including: scintigraphic transit studies, anorectal manometry, colonic manometry, and studies using a wireless motility capsule.

High amplitude propagated contractions

While most colonic motor activity is segmental and non-propulsive, colonic high amplitude propagated contractions (HAPC) can transfer colonic contents over long distances and often precede defecation. High amplitude propagated contractions occur spontaneously, in response to pharmacological agents or colonic distention. A subset of patients with slow transit constipation have fewer HAPC. In this issue of Neurogastroenterology and Motility, Rodriguez et al. report that anal relaxation during spontaneous and bisacodyl-induced HAPC exceeds anal relaxation during rectal distention in constipated children undergoing colonic manometry. Moreover, and consistent with a neural mechanism, anal relaxation often precedes arrival of HAPC in the left colon. High amplitude propagated contractions are also used to evaluate the motor response to a meal and pharmacological stimuli (e.g., bisacodyl, neostigmine) and to identify colonic inertia during colonic motility testing in chronic constipation. This editorial comprehensively reviews the characteristics, physiology and pharmacology of HAPC, their assessment by manometry, and relevance to constipation and diarrhea.

Internal anal sphincter relaxation associated with bisacodyl-induced colonic high amplitude propagating contractions in children with constipation: a colo-anal reflex?

BACKGROUND

Describe the association of internal anal sphincter (IAS) relaxation with colonic high- amplitude peristaltic contractions (HAPCs).

METHODS

Retrospective review of colon manometry tracings of children with constipation to determine the IAS relaxation characteristics associated with HAPC's (HAPC-IASR) events and compare them to the those seen during the performance of the anorectal manometry (ARMRAIR) events.

KEY RESULTS

A total of 70 HAPC- IASRs were observed in 15 patients, 65 after bisacodyl, two during fasting and three after a meal. In 64% of events, the IAS relaxation started when the HAPC reached left colon and in 36% as proximal as the hepatic flexure. High- amplitude peristaltic contraction propagation seems to be important in HAPC-IASR characteristics; those propagating distal to sigmoid colon demonstrated larger and longer IAS relaxation as well as lower residual pressure, but equivalent resting pressure compared with HAPC's ending proximal to sigmoid colon. Although IAS resting pressure was comparable for ARM-RAIRs and HAPC-IASRs, the duration and magnitude of anal relaxation was higher, and the anal residual pressure was lower in HAPC-IASRs.

CONCLUSIONS & INFERENCES

We demonstrated that IAS relaxation in constipated children is associated with HAPCs migrating in the proximal and distal colon; in most cases, starting when peristalsis is migrating through left colon and in an important proportion while migrating proximally. We also demonstrated that HAPC-IASRs are different from ARM-RAIRs suggesting a neurally mediated reflex. Finally, the IAS relaxation characteristics are highly dependent on the degree of propagation of HAPCs, which could have important implications in the understanding of defecation disorders.