Abnormal predefecatory colonic motor patterns define constipation in obstructed defecation

Prediction method of human defecation based on informer audio data augmentation and improved residual network

Defecation care for disabled patients is a major challenge in health management. Traditional post-defecation treatment will bring physical injury and negative emotions to patients, while existing pre-defecation forecasting care methods are physically intrusive. On the basis of exploring the mechanism of defecation intention generation, and based on the characteristic analysis and clinical application of bowel sounds, it is found that the generation of desire to defecate and bowel sounds are correlated to a certain extent. Therefore, a deep learning-based bowel sound recognition method is proposed for human defecation prediction. The wavelet domain based Wiener filter is used to filter the bowel sound data to reduce other noise. Statistical analysis, fast Fourier transform and wavelet packet transform are used to extract the integrated features of bowel sound in time, frequency and time-frequency domain. In particular, an audio signal expansion data algorithm based on the Informer model is proposed to solve the problem of poor generalization of the training model caused by the difficulty of collecting bowel sound in reality. An improved one-dimensional residual network model (1D-IResNet) for defecation classification prediction is designed based on multi-domain features. The experimental results show that the proposed bowel sound augmentation strategy can effectively improve the data sample size and increase the sample diversity. Under the augmented dataset, the training speed of the 1D-IResNet model is accelerated, and the classification accuracy reaches 90.54 %, the F1 score reaches 83.88 %, which achieves a relatively good classification stability while maintaining a high classification index.

The Effect of Biorelevant Hydrodynamic Conditions on Drug Dissolution from Extended-Release Tablets in the Dynamic Colon Model

The in vitro release of theophylline from an extended-release dosage form was studied under different hydrodynamic conditions in a United States Pharmacopoeial (USP) dissolution system II and a bespoke in vitro tubular model of the human colon, the Dynamic Colon Model (DCM). Five biorelevant motility patterns extracted from in vivo data were applied to the DCM, mimicking the human proximal colon under baseline conditions and following stimulation using polyethylene glycol or maltose; these represent the lower and upper bounds of motility normally expected in vivo. In the USPII, tablet dissolution was affected by changing hydrodynamic conditions at different agitation speeds of 25, 50 and 100 rpm. Applying different motility patterns in the DCM affected the dissolution profiles produced, with theophylline release at 24 h ranging from 56.74 ± 2.00% (baseline) to 96.74 ± 9.63% (maltose-stimulated). The concentration profiles of theophylline were markedly localized when measured at different segments of the DCM tube, highlighting the importance of a segmented lumen in intestine models and in generating spatial information to support simple temporal dissolution profiles. The results suggested that the shear stresses invoked by the unstimulated, healthy adult human colon may be lower than those in the USPII at 25 rpm and thus insufficient to achieve total release of a therapeutic compound from a hydroxyethyl cellulose matrix. When operated under stimulated conditions, drug release in the DCM was between that achieved at 25 and 50 rpm in the USPII.

High-resolution anorectal manometry in children with functional constipation with or without fecal incontinence

BACKGROUND

High-resolution anorectal manometry (HR-ARM) is expected to be better than conventional manometry. Our aim was to characterize HR-ARM pressures in children with functional constipation (FC), with or without fecal incontinence (FI).

METHODS

Children with diagnosis of FC, with or without FI, according to Rome-IV criteria, were enrolled. All patients underwent HR-ARM using 24-channel water-perfused catheter.

RESULTS

Twenty-nine consecutive children (M/F: 21/8; mean age ± SD: 9.5 ± 3.1 years; range 4-15), of whom 21 affected by FC without FI (mean age ± SD: 9.3 ± 3.23 years) and 8 affected by FC with FI (mean age ± SD: 10.2 ± 3.08 years), were enrolled. No significant differences were found regard to gender and age. The analysis of HR-ARM 3D plots demonstrated asymmetry of the anal canal, with higher pressures in distal halves. Comparing pressures between the two groups, we found lower values in FC with FI than in FC without FI group, with a statistically significance for maximum and mean resting pressures (P = .032 and P = .008, respectively). When evaluating our study population respect to asymptomatic children, we found lower resting pressures, lower maximum squeeze pressure, and higher rectoanal inhibitory reflex (RAIR) values.

CONCLUSIONS

Our data demonstrate that HR-ARM pressures at rest and during squeezing in FC with FI children are lower than FC without FI subjects, particularly in anteroposterior quadrants. Compared to children without lower gastrointestinal symptoms, children with FC with or without FI show lower pressures and higher values of RAIR.

On the nature of high-amplitude propagating pressure waves in the human colon

Characterization of high-amplitude propagating pressure waves (HAPWs or HAPCs) plays a key role in diagnosis of colon dysmotility using any type of colonic manometry. With the introduction of high-resolution manometry, more insight is gained into this most prominent propulsive motor pattern. Here, we use a water-perfused catheter with 84 sensors with intervals between measuring points of 1 cm throughout the colon, for 6-8 h, in 19 healthy subjects. The catheter contained a balloon to evoke distention. We explored as stimuli a meal, balloon distention, oral prucalopride, and bisacodyl injection, with a goal to optimally evoke HAPWs. We developed a quantitative measure of HAPW activity, the "HAPW Index." Our protocol elicited 290 HAPWs. 21% of HAPWs were confined to the proximal colon with an average amplitude of 75.3 ± 3.3 mmHg and an average HAPW Index of 440 ± 58 mmHg·m·s. 29% of HAPWs started in the proximal colon and ended in the transverse or descending colon, with an average amplitude of 87.9 ± 3.1 mmHg and an average HAPW Index of 3,344 ± 356 mmHg·m·s. Forty-nine percent of HAPWs started and ended in the transverse or descending colon with an average amplitude of 109.3 ± 3.3 mmHg and an average HAPW Index of 2,071 ± 195 mmHg·m·s. HAPWs with and without simultaneous pressure waves (SPWs) initiated the colo-anal reflex, often abolishing 100% of anal sphincter pressure. Rectal bisacodyl and proximal balloon distention were the most optimal stimuli to evoke HAPWs. These measures now allow for a confident diagnosis of abnormal motility in patients with colonic motor dysfunction.NEW & NOTEWORTHY High-amplitude propagating pressure waves (HAPWs) were characterized using 84 sensors throughout the entire colon in healthy subjects, taking note of site of origin, site of termination, amplitude, and velocity, and to identify optimal stimuli to evoke HAPWs. Three categories of HAPWs were identified, including the associated colo-anal reflex. Proximal balloon distention and rectal bisacodyl were recognized as reliable stimuli for evoking HAPWs, and a HAPW Index was devised to quantify this essential colonic motor pattern.

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.

High-resolution anorectal manometry: An expensive hobby or worth every penny?

Introduced approximately 10 years ago, high-resolution manometry catheters have fostered interest in anorectal manometry. This review, which accompanies two articles in this issue of Neurogastroenterology and Motility, reviews the methods, clinical indications, utility, and pitfalls of anorectal manometry and revisits the American Gastroenterological Association (AGA) Medical Position Statement on Anorectal Testing Techniques, which was last published in 1999. High-resolution manometry provides a refined assessment of the anorectal pressure profile, obviates the need for station pull-through maneuvers, and minimizes movement artifacts. In selected cases, this refined assessment may be useful for identifying structural abnormalities or anal weakness. However, many manometry patterns that were previously regarded as abnormal are also observed in a majority of healthy patients, which substantially limits the utility of manometry for identifying defecatory disorders. It is our impression that most conclusions of the AGA medical position statement from 1999 remain valid today. High-resolution techniques have not substantially affected the number of publications on or management of anorectal disorders. The ongoing efforts of an international working group to standardize techniques for anorectal manometry are welcome. Although high-resolution manometry is more than an expensive hobby, improvements in catheter design and further research to rigorously define and evaluate these techniques are necessary to determine if they are worth every penny.

Transcutaneous Sacral Electrical Stimulation for Chronic Functional Constipation

BACKGROUND

Transcutaneous sacral nerve stimulation is reported to improve symptoms of fecal incontinence. Chronic constipation may also respond to stimulation, but this is poorly reported in the literature.

OBJECTIVE

The study assessed the efficacy of transcutaneous electrical stimulation directly over the sacral nerve roots in chronic constipation.

PATIENTS

Chronic functional constipation was established in all patients using the Rome III criteria.

SETTING

The therapy was self-administered at home.

DESIGN/INTERVENTION

A pilot study was conducted of transcutaneous sacral stimulation given over a 4-week period for 12 hours a day.

MAIN OUTCOME MEASURES

Patients were assessed using the Patient Assessment of Constipation Symptoms, the Patient Assessment of Constipation Quality of Life, and the Cleveland constipation tool. A Global Rating of Change measure and a 1-week bowel diary was kept for the final week and compared with baseline.

RESULTS

Of the 20 patients recruited (16 female, median age 38.5 years), 80% (16) completed the trial. Five (31%) patients reported at least a point reduction in the Patient Assessment of Constipation Symptoms score, 4 (25%) deteriorated, and 7 (44%) improved by less than one point. Median (interquartile range) Patient Assessment of Constipation Symptoms scores were 2.33 (2.34) at baseline and 2.08 (2.58) at follow-up (p = 0.074). Median scores for the Patient Assessment of Constipation Quality of Life and Cleveland systems were 3.00 (1.64) and 17.15 (18) at baseline and 2.22 (3.04) and 15.31 (12) at follow-up (p = 0.096 and 0.111). One-third of patients reported a positive Global Rating of Change measure, although 68% required concurrent laxatives during the trial.

LIMITATIONS

This is a pilot study and is limited by its small sample size.

CONCLUSIONS

Continuous transcutaneous sacral stimulation in the short term appears to be ineffective for chronic constipation. Larger well-powered studies with intermittent stimulation regimens are required to investigate this further.

Constipation and Outcomes of Cecostomy

Constipation, defined as delay or difficulty in defecation, present for 2 or more weeks, is a common problem encountered by both primary and specialty medical providers. There are no randomized controlled trials on the use of antegrade enemas in the pediatric population. Most published papers are based on the experience at a particular center. The aim of this article is to describe the pathophysiology of constipation, review the contribution of colonic manometry to the diagnosis of constipation, summarize the advancements in the management of constipation through the use of antegrade enemas, and study the outcomes of cecostomy at different centers. This study is a comprehensive literature review generated by computerized search of literature, supplemented by review of monographs and textbooks in pathology, gastroenterology, and surgery. Literature search was performed using the publications from 1997 to 2012. The search included publications of all types presenting or reviewing data on cecostomy. The antegrade continence enema is a therapeutic option for defecation disorders when maximal conventional therapy is not successful. Symptoms of defecation disorders in children with different underlying etiologies improve significantly after a cecostomy is created. In addition, there is a benefit on the patients' physical activity, healthcare utilization, and general well-being. Based on the review of published literature it seems that antegrade enemas are a successful therapeutic option in children with severe constipation and/or fecal incontinence. With the advent of cecostomy buttons, patient compliance and the overall cosmetic appearance have improved.

Quantification of in vivo colonic motor patterns in healthy humans before and after a meal revealed by high-resolution fiber-optic manometry

BACKGROUND

Until recently, investigations of the normal patterns of motility of the healthy human colon have been limited by the resolution of in vivo recording techniques.

METHODS

We have used a new, high-resolution fiber-optic manometry system (72 sensors at 1-cm intervals) to record motor activity from colon in 10 healthy human subjects.

KEY RESULTS

In the fasted colon, on the basis of rate and extent of propagation, four types of propagating motor pattern could be identified: (i) cyclic motor patterns (at 2-6/min); (ii) short single motor patterns; (iii) long single motor patterns; and (iv) occasional retrograde, slow motor patterns. For the most part, the cyclic and short single motor patterns propagated in a retrograde direction. Following a 700 kCal meal, a fifth motor pattern appeared; high-amplitude propagating sequences (HAPS) and there was large increase in retrograde cyclic motor patterns (5.6 ± 5.4/2 h vs 34.7 + 19.8/2 h; p < 0.001). The duration and amplitude of individual pressure events were significantly correlated. Discriminant and multivariate analysis of duration, gradient, and amplitude of the pressure events that made up propagating motor patterns distinguished clearly two types of pressure events: those belonging to HAPS and those belonging to all other propagating motor patterns.

CONCLUSIONS & INFERENCES

This work provides the first comprehensive description of colonic motor patterns recorded by high-resolution manometry and demonstrates an abundance of retrograde propagating motor patterns. The propagating motor patterns appear to be generated by two independent sources, potentially indicating their neurogenic or myogenic origin.

Long-term outcomes and quality of life after subtotal colectomy combined with modified Duhamel procedure for adult Hirschsprung's disease

BACKGROUND

Subtotal colectomy combined with modified Duhamel procedure (Jinling procedure) was used in patients with adult Hirschsprung's disease (AHD) at Jinling Hospital in the last decade. The aim of this study is to evaluate the safety, effectiveness and quality of life of Jinling procedure for AHD.

MATERIALS AND METHODS

All the data are from the database of the Jinling Hospital Constipation Registry System. Primary outcomes, including safety (morbidity and adverse events), effectiveness (satisfaction rate, Wexner constipation scale (WCS) and bowel function score (BFS)) and gastrointestinal quality of life index (GIQLI), were all evaluated.

RESULTS

Fifty-nine patients were available for this study and the mean postoperative period was 44 months. Seventeen major complications were found in 11 patients and most of the complications could be managed conservatively. A significant improvement in WCS, BFS and GIQLI at 6 months postoperatively was obtained.

CONCLUSION

Jinling procedure is safe and effective for AHD.

Chronic constipation: a critical review

Chronic constipation is a very common symptom that is rarely associated with life-threatening diseases, but has a substantial impact on patient quality of life and consumption of healthcare resources. Despite the large number of affected patients and the social relevance of the condition, no cost-effectiveness analysis has been made of any diagnostic or therapeutic algorithm, and there are few data comparing different diagnostic and therapeutic approaches in the long term. In this scenario, increasing emphasis has been placed on demonstrating that a number of older and new therapeutic options are effective in treating chronic constipation in well-performed randomised controlled trials, but there is still debate as to when these therapeutic options should be included in diagnostic and therapeutic algorithms. The aim of this review is to perform a critical evaluation of the current diagnostic and therapeutic options available for adult patients with chronic constipation in order to identify a rational patient approach; furthermore we attempt to clarify some of the more controversial points to aid clinicians in managing this symptom in a more efficacious and cost-effective manner.

Colonic transit before and after resection rectopexy for full-thickness rectal prolapse

BACKGROUND

The objective of this study was to measure the change in colonic transit time after resection rectopexy for complete rectal prolapse.

METHODS

We prospectively carried out isotope colonic transit studies before resection rectopexy in 38 patients with full-thickness complete rectal prolapse and invited them to attend for a postoperative transit study at least 1 year after resection rectopexy.

RESULTS

Preoperatively, 27 (70 %) patients had abnormally prolonged colonic transit times, while 11 had normal colonic transit. Twenty-two (61 %) patients agreed to attend for a three-day colonic transit study. Resection rectopexy failed to correct delayed colonic transit in all patients with abnormal preoperative tests, while 4 patients developed new delayed transit and 2 with normal transit were unchanged.

CONCLUSIONS

The study suggests that most prolapse patients have a pan-colonic motility disorder that is not corrected by rectopexy and resection of most of the left colon. If resection rectopexy fails to correct abnormal transit, this study questions the rationale for continuing to offer resection and supports less invasive surgical procedures such as ventral rectopexy.

Classification of normal and abnormal colonic motility based on cross-correlations of pancolonic manometry data

BACKGROUND

Manual analysis of data acquired from manometric studies of colonic motility is laborious, subject to laboratory bias and not specific enough to differentiate all patients from control subjects. Utilizing a cross-correlation technique, we have developed an automated analysis technique that can reliably differentiate the motor patterns of patients with slow transit constipation (STC) from those recorded in healthy controls.

METHODS

Pancolonic manometric data were recorded from 17 patients with STC and 14 healthy controls. The automated analysis involved calculation of an indicator value derived from cross-correlations calculated between adjacent recording sites in a manometric trace. The automated technique was conducted on blinded real data sets (observed) and then to determine the likelihood of positive indicator values occurring by chance, the channel number within each individual data set were randomized (expected) and reanalyzed.

KEY RESULTS

In controls, the observed indicator value (3.2 ± 1.4) was significantly greater than that predicted by chance (0.8 ± 1.5; P < 0.0001). In patients, the observed indicator value (-2.7 ± 1.8) did not differ from that predicted by chance (-3.5 ± 1.6; P = 0.1). The indicator value for controls differed significantly from that of patients (P < 0.0001), with all individual patients falling outside of the range of indicator values for controls.

CONCLUSIONS & INFERENCES

Automated analysis of colonic manometry data using cross-correlation separated all patients from controls. This automated technique indicates that the contractile motor patterns in STC patients differ from those recorded in healthy controls. The analytical technique may represent a means for defining subtypes of constipation.

The effect of luminal content and rate of occlusion on the interpretation of colonic manometry

BACKGROUND

Manometry is commonly used for diagnosis of esophageal and anorectal motility disorders. In the colon, manometry is a useful tool, but clinical application remains uncertain. This uncertainty is partly based on the belief that manometry cannot reliably detect non-occluding colonic contractions and, therefore, cannot identify reliable markers of dysmotility. This study tests the ability of manometry to record pressure signals in response to non-lumen-occluding changes in diameter, at different rates of wall movement and with content of different viscosities.

METHODS

A numerical model was built to investigate pressure changes caused by localized, non-lumen-occluding reductions in diameter, similar to those caused by contraction of the gut wall. A mechanical model, consisting of a sealed pressure vessel which could produce localized reductions in luminal diameter, was used to validate the model using luminal segments formed from; (i) natural latex; and (ii) sections of rabbit proximal colon. Fluids with viscosities ranging from 1 to 6800 mPa s(-1) and luminal contraction rates over the range 5-20 mmHg s(-1) were studied.

KEY RESULTS

Manometry recorded non-occluding reductions in diameter, provided that they occurred with sufficiently viscous content. The measured signal was linearly dependent on the rate of reduction in luminal diameter and also increased with increasing viscosity of content (R(2) = 0.62 and 0.96 for 880 and 1760 mPa s(-1), respectively).

CONCLUSIONS & INFERENCES

Manometry reliably registers non-occluding contractions in the presence of viscous content, and is therefore a viable tool for measuring colonic motility. Interpretation of colonic manometric data, and definitions based on manometric results, must consider the viscosity of luminal content.

Review article: faecal incontinence in children: epidemiology, pathophysiology, clinical evaluation and management

BACKGROUND

Faecal incontinence (FI) in children is a significant gastrointestinal problem, with great personal and social impacts. It is characterised by recurrent loss of faecal matter into the underwear. Both functional and organic causes contribute to its aetiology with the former predominating.

AIM

To review the epidemiology, pathophysiology, clinical evaluation and management of functional faecal incontinence in children.

METHODS

A PubMed search was conducted using search terms f(a)ecal incontinence, and encopresis. Articles on epidemiology, pathophysiology, clinical evaluation, investigation and management of functional FI in children were retrieved and assessed.

RESULTS

Community prevalence of this distressing problem ranges from 0.8% to 7.8% globally. Male: female ratio varies from 3:1 to 6:1. The diagnosis of FI is often based on established clinical criteria. The majority (82%) have constipation associated functional FI. Biopsychosocial factors play a crucial role in the pathogenesis. Limited physiological testing of anorectal function is recommended in the diagnostic procedures, particularly in children with atypical symptoms and possible organic disorders. Management of FI needs a multidisciplinary approach which includes establishment of an effective doctor-patient partnership, understanding the underlying mechanisms, pharmacotherapy and behavioural treatment. Approximately 15% of children with functional nonretentive faecal incontinence (FNRFI) had the same symptoms at the age of 18 years.

CONCLUSION

Significant therapeutic advances have been made for retentive faecal incontinence, but treatment options for functional nonretentive faecal incontinence are limited. Limited long-term outcome data show that the majority outgrow faecal incontinence. A substantial proportion of children progress to adulthood with faecal incontinence.

Long-term follow-up of the Jinling procedure for combined slow-transit constipation and obstructive defecation

BACKGROUND

Surgery is indicated for chronic constipation refractory to conservative therapy. The treatment of combined slow-transit constipation and obstructive defecation is controversial.

OBJECTIVE

The aim of the study is to describe the Jinling procedure and examine safety, effectiveness, and quality of life over 4 years of follow-up.

DESIGN

The study is a retrospective review of prospectively gathered data in a patient registry database.

SETTINGS

This investigation was conducted at a tertiary-care gastroenterology surgical center in China.

PATIENTS

The study included 117 consecutive patients with slow-transit constipation combined with obstructive defecation treated between January 2005 and December 2007.

INTERVENTION

The Jinling procedure modifies the classic procedure of subtotal colectomy with colorectal anastomosis by adding a new side-to-side cecorectal anastomosis to solve the coexistence of obstructive defecation and slow-transit constipation in one operation.

MAIN OUTCOME MEASURES

We measured morbidity and mortality rates, Wexner constipation scores, and Gastrointestinal Quality of Life Index at baseline and after 1, 6, 12, 24, 36 and 48 months of follow-up.

RESULTS

A total of 117 patients underwent the Jinling procedure, which was laparoscopically assisted in 56 patients (47.9%) and an open procedure in 61 patients (52.1%). Of the total, 72 patients (61.5%) had undergone previous surgical intervention without improvement. A total of 28 complications and adverse events were reported in 117 procedures, giving an overall morbidity rate of 23.9%; 23 patients (19.7%) had 1 or more events. Most complications were managed conservatively. A significant reduction in Wexner constipation score was observed from baseline (mean, 21.9) to 1 month (mean, 9.8), and the reduction was maintained at 48 months (mean 5.1; p < 0.001). Compared with baseline, significant overall improvements were also seen in gastrointestinal quality of life at 12, 24, and 48 months of follow-up (p < 0.01).

LIMITATIONS

This study did not include a comparison group.

CONCLUSIONS

Our clinical practice demonstrates that Jinling procedure is safe and effective for refractory slow-transit constipation associated with obstructive defecation, with minimal major complications, significant improvement of quality of life, and a high satisfaction rate after 4-year follow up.

High-resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation

BACKGROUND

Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high-resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl-induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology.

METHODS

Eighteen children (10 males, median age: 7.5 years) with refractory STC underwent stationary colonic HRM before segmental colonic resection. Six age-matched constipated children with normal colonic transit served as controls. Colonic resection specimens underwent histopathological analysis. Conventional manometric parameters and area under the curve (AUC) during a 1-min period following bisacodyl-induced HAPSs [PBAUC(1) ], as measure of FQ, were calculated.

KEY RESULTS

Numbers of postbisacodyl HAPSs in descending and sigmoid segments were lower in patients than controls (P < 0.01, respectively). Low amplitude propagating sequences (LAPSs) were common prebisacodyl in controls and rare in STC (P < 0.001), whereas postbisacodyl LAPS were more common in STC (P < 0.001). Postbisacodyl, both retrograde propagating contractions and bursts of contractions were present in STC patients only (P < 0.001 and P < 0.01). Postbisacodyl simultaneous pressurization was seen only in STC (P < 0.05 and P < 0.001, in descending and rectosigmoid segments). Histological abnormalities were present in 17/18. Fourteen were neurogenic, one neuro-myogenic, and two myogenic. In segments with HAPS, PBAUC(1) was predictive of colonic neuropathy using a cutoff of 205 mmHg.s(-1) (Sensitivity 100%, specificity 86%, PPV92%, NPV100%).

CONCLUSIONS & INFERENCES

PBAUC(1) is increased in multiple colonic segments in neuropathic pediatric STC and constitutes a sensitive and specific biomarker of neuropathy.

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.

The physiology of human defecation

Human defecation involves integrated and coordinated sensorimotor functions, orchestrated by central, spinal, peripheral (somatic and visceral), and enteric neural activities, acting on a morphologically intact gastrointestinal tract (including the final common path, the pelvic floor, and anal sphincters). The multiple factors that ultimately result in defecation are best appreciated by describing four temporally and physiologically fairly distinct phases. This article details our current understanding of normal defecation, including recent advances, but importantly identifies those areas where knowledge or consensus is still lacking. Appreciation of normal physiology is central to directed treatment of constipation and also of fecal incontinence, which are prevalent in the general population and cause significant morbidity.

An assessment of enteric nervous system and estroprogestinic receptors in obstructed defecation associated with rectal intussusception

BACKGROUND

The pathophysiological basis of obstructed defecation (OD) is still incompletely understood. In particular, few or no data are available concerning the enteric nervous system (ENS) in this condition. We investigated ENS abnormalities in patients with OD, undergoing surgery, together with the presence of estrogen (α and β) and progesterone receptors, and compare the results with those obtained in controls.

METHODS

Full-thickness rectal samples were obtained from 17 patients undergoing stapled transanal rectal resection for OD associated with rectal intussusception. Samples were analyzed by immunohistochemistry for enteric neurons, enteric glial cells, interstitial cells of Cajal (ICC), and for estrogen and progesterone receptors. Data were compared with those obtained in 10 controls.

KEY RESULTS

No differences between patients and controls were found for enteric neurons, whereas (compared with controls) OD patients displayed a significant decrease of enteric glial cells in both the submucous (P = 0.0006) and the myenteric (P < 0.0001) plexus. ICC were significantly increased in patients in the submucosal surface (P < 0.0001) and the myenteric area (P < 0.0001). Concerning estroprogestinic receptors, both were present on ICC in patients and controls. Estrogen receptors α and progesterone receptors were absent on enteric neurons and enteric glial cells in patients and controls, whereas estrogen receptors β were present in all controls and in 69% of patients' enteric neurons (P = 0.18) and in 12% of patients' glial cells (P = 0.0001).

CONCLUSIONS & INFERENCES

Patients with OD associated to rectal intussusception display abnormalities of the ENS and of estrogen receptors β.

Morphological alterations of the enteric nervous system in young male patients with rectal prolapse

OBJECTIVES

The pathogenesis of rectal prolapse (RP) defined by a circumferential, full-thickness invagination of the rectal wall into the anal canal is controversial. RP is normally encountered in elderly women and attributed to several etiological factors (e.g., advanced age, pudendal nerve injury, laxity of supporting ligaments). RP affecting young male patients is unlikely to be explained by these factors and may be due to a rectal motility disorder. Therefore, the enteric nervous system (ENS) as key regulator of intestinal motility was evaluated by a systematic morphometric analysis.

PATIENTS AND METHODS

Full-thickness rectosigmoid specimens obtained from young male patients with symptomatic RP (n = 5) and male controls (n = 15) were processed for conventional histology and immunohistochemistry using anti-HuC/D as pan-neuronal marker. Enteric ganglia, nerve and glial cells were quantified separately in the myenteric (MP) and submucosal plexus (SMP).

RESULTS

Compared to controls, patients with RP showed significantly (p < 0.05) increased mean ganglionic area both in MP and SMP, increased mean neuronal content of submucosal ganglia, and nearly threefold higher frequency of submucosal ganglia containing ≥7 neurons.

CONCLUSION

The morphometric analysis reveals distinct quantitative alterations of the ENS in young male patients with RP mainly characterized by submucosal hyperganglionosis similar to histopathological features described in intestinal neuronal dysplasia. The data give evidence that RP in this unusual subgroup is associated with morphological changes of enteric ganglia which may contribute to the development of RP and complement established etiological concepts.

Factor analysis identifies subgroups of constipation

AIM: To determine whether distinct symptom groupings exist in a constipated population and whether such grouping might correlate with quantifiable pathophysiological measures of colonic dysfunction.

METHODS: One hundred and ninety-one patients presenting to a Gastroenterology clinic with constipation and 32 constipated patients responding to a newspaper advertisement completed a 53-item, wide-ranging self-report questionnaire. One hundred of these patients had colonic transit measured scintigraphically. Factor analysis determined whether constipation-related symptoms grouped into distinct aspects of symptomatology. Cluster analysis was used to determine whether individual patients naturally group into distinct subtypes.

RESULTS: Cluster analysis yielded a 4 cluster solution with the presence or absence of pain and laxative unresponsiveness providing the main descriptors. Amongst all clusters there was a considerable proportion of patients with demonstrable delayed colon transit, irritable bowel syndrome positive criteria and regular stool frequency. The majority of patients with these characteristics also reported regular laxative use.

CONCLUSION: Factor analysis identified four constipation subgroups, based on severity and laxative unresponsiveness, in a constipated population. However, clear stratification into clinically identifiable groups remains imprecise.

Colonic dysmotility in constipation

Constipation is a common and distressing condition with major morbidity, health care burden, and impact on quality of life. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in the most severe cases of chronic constipation and physiological testing plays a role in identifying the colonic dysmotility and the subsequent patient management. Measurement of colonic motor patterns and transit has enhanced our knowledge of normal and abnormal colonic motor physiology. The scope of this review encompasses the latest findings that improve our understanding of the motility disorders associated with colonic dysfunction in both the paediatric and adult population suffering from constipation.

Chronic constipation: lessons from animal studies

Chronic constipation is a highly debilitating condition, affecting a significant proportion of the community. The burden to the health care system and impact on individual patients quality of life is immense. Unfortunately, the aetiology underlying chronic constipation is poorly understood and animal models are being used increasingly to investigate possible intrinsic neurogenic and myogenic mechanisms leading to relevant colonic sensori-motor dysfunction. Recently, major advances have been made in our understanding of the mechanisms that underlie propagating contractions along the large intestine, such as peristalsis and colonic migrating motor complexes in laboratory animals, particularly in guinea-pigs and mice. The first recordings of cyclical propagating contractions along the isolated whole human colon have now also been made. This review will highlight some of these advances and how impairments to these motility patterns may contribute to delayed colonic transit, known to exist in a proportion of patients with chronic constipation.

Accurate localization of a fall in pH within the ileocecal region: validation using a dual-scintigraphic technique

Stereotypical changes in pH occur along the gastrointestinal (GI) tract. Classically, there is an abrupt increase in pH on exit from the stomach, followed later by a sharp fall in pH, attributed to passage through the ileocecal region. However, the precise location of this latter pH change has never been conclusively substantiated. We aimed to determine the site of fall in pH using a dual-scintigraphic technique. On day 1, 13 healthy subjects underwent nasal intubation with a 3-m-long catheter, which was allowed to progress to the distal ileum. On day 2, subjects ingested a pH-sensitive wireless motility capsule labeled with 4 MBq (51)Chromium [EDTA]. The course of this, as it travelled through the GI tract, was assessed with a single-headed γ-camera using static and dynamic scans. Capsule progression was plotted relative to a background of 4 MBq ¹¹¹Indium [diethylenetriamine penta-acetic acid] administered through the catheter. Intraluminal pH, as recorded by the capsule, was monitored continuously, and position of the capsule relative to pH was established. A sharp fall in pH was recorded in all subjects; position of the capsule relative to this was accurately determined anatomically in 9/13 subjects. In these nine subjects, a pH drop of 1.5 ± 0.2 U, from 7.6 ± 0.05 to 6.1 ± 0.1 occurred a median of 7.5 min (1-16) after passage through the ileocecal valve; location was either in the cecum (n = 5), ascending colon (n = 2), or coincident with a move from the cecum to ascending colon (n = 2). This study provides conclusive evidence that the fall in pH seen within the ileocolonic region actually occurs in the proximal colon. This phenomenon can be used as a biomarker of transition between the small and large bowel and validates assessment of regional GI motility using capsule technology that incorporates pH measurement.

Pancolonic spatiotemporal mapping reveals regional deficiencies in, and disorganization of colonic propagating pressure waves in severe constipation

BACKGROUND

The morphology, motor responses and spatiotemporal organization among colonic propagating sequences (PS) have never been defined throughout the entire colon of patients with slow transit constipation (STC). Utilizing the technique of spatiotemporal mapping, we aimed to demonstrate 'manometric signatures' that may serve as biomarkers of the disorder.

METHODS

In 14 female patients with scintigraphically confirmed STC, and eight healthy female controls, a silicone catheter with 16 recording sites spanning the colon at 7.5 cm intervals was positioned colonoscopically with the tip clipped to the cecum. Intraluminal pressures were recorded for 24 h.

KEY RESULTS

Pan-colonic, 24 h, spatiotemporal mapping identified for the first time in STC patients: a marked paucity of propagating pressure waves in the midcolon (P = 0.01), as a consequence of a significant (P < 0.0001) decrease in extent of propagation of PS originating in the proximal colon; an increase in frequency of retrograde PS in the proximal colon; a significant reduction in the spatiotemporal organization among PS (P < 0.001); absence of the normal nocturnal suppression of PS.

CONCLUSIONS & INFERENCES

Pancolonic, 24 h, spatiotemporal pressure mapping readily identifies characteristic disorganization among consecutive PS, regions of diminished activity and absent or deficient fundamental motor patterns and responses to physiological stimuli. These features are all likely to be important in the pathophysiology of slow transit constipation.

Paediatric and adult colonic manometry: A tool to help unravel the pathophysiology of constipation

Colonic motility subserves large bowel functions, including absorption, storage, propulsion and defaecation. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in chronic constipation, a heterogeneous condition which is extremely prevalent in the general population, and has huge socioeconomic impact and individual suffering. Physiological testing plays a crucial role in patient management, as it is now accepted that symptom-based assessment, although important, is unsatisfactory as the sole means of directing therapy. Colonic manometry provides a direct method for studying motor activities of the large bowel, and this review provides a contemporary understanding of how this technique has enhanced our knowledge of normal colonic motor physiology, as well as helping to elucidate pathophysiological mechanisms underlying constipation. Methodological approaches, including available catheter types, placement technique and recording protocols, are covered, along with a detailed description of recorded colonic motor activities. This review also critically examines the role of colonic manometry in current clinical practice, and how manometric assessment may aid diagnosis, classification and guide therapeutic intervention in the constipated individual. Most importantly, this review considers both adult and paediatric patients. Limitations of the procedure and a look to the future are also addressed.

Clinical utility of colonic and anorectal manometry in chronic constipation

Constipation is one of the most common digestive problems in North America with significant psychosocioeconomic implications. It is caused by either a primary disorder of colonic and anorectal function or by many secondary conditions such as constipating drugs, metabolic disorders and other colorectal problems. Given the heterogeneity of problems that cause constipation, defining the underlying pathophysiology is increasingly being recognized as a key step toward optimal management. Colonic manometry with sensation and tone assessment (barostat) and anorectal manometry with rectal sensation and compliance assessment and balloon expulsion test can provide a comprehensive evaluation of colonic and anorectal sensorimotor function and facilitate a diagnosis of slow transit constipation, dyssynergic defecation or irritable bowel syndrome, or an overlap of these disorders. This review provides a critical appraisal of the role of manometric techniques toward augmenting our understanding of colonic and anorectal physiology, both in health and constipation and discussing their clinical utility in the diagnosis and management of chronic constipation.

Wireless pH-motility capsule for colonic transit: prospective comparison with radiopaque markers in chronic constipation

BACKGROUND

Colon transit (CT) measurements are used in the management of significant constipation. The radiopaque marker (ROM) method provides limited information.

METHODS

We proposed to validate wireless motility capsule (WMC), that measures pH, pressure and temperature, to ROM measurement of CT in patients with symptomatic constipation evaluated at multiple centers. Of 208 patients recruited, 158 eligible patients underwent simultaneous measurement of colonic transit time (CTT) using ROM (Metcalf method, cut off for delay >67 h), and WMC (cutoff for delay >59 h). The study was designed to demonstrate substantial equivalence, defined as diagnostic agreement >65% for patients who had normal or delayed ROM transit.

KEY RESULTS

Fifty-nine of 157 patients had delayed ROM CT. Transit results by the two methods differed: ROM median 55.0 h [IQR 31.0-85.0] and WMC (43.5 h [21.7-70.3], P < 0.001. The positive percent agreement between WMC and ROM for delayed transit was approximately 80%; positive agreement in 47 by WMC/59 by ROM or 0.796 (95% CI = 0.67-0.98); agreement vs null hypothesis (65%) P = 0.01. The negative percent agreement (normal transit) was approximately 91%: 89 by WMC/98 by ROM or 0.908 (95% CI = 0.83-0.96); agreement vs null hypothesis (65%), P = 0.00001. Overall device agreement was 87%. There were significant correlations (P < 0.001) between ROM and WMC transit (CTT [r = 0.707] and between ROM and combined small and large bowel transit [r = 0.704]). There were no significant adverse events.

CONCLUSIONS & INFERENCES

The 87% overall agreement (positive and negative) validates WMC relative to ROM in differentiating slow vs normal CT in a multicenter clinical study of constipation.

Bowel preparation affects the amplitude and spatiotemporal organization of colonic propagating sequences

BACKGROUND

Colonic manometry is performed using either colonoscopically assisted catheter placement, after bowel preparation, or nasocolonic intubation of the unprepared bowel. There has been little systematic evaluation of the effects of bowel cleansing upon colonic propagating pressure wave sequences.

METHODS

Eight healthy volunteers underwent nasocolonic placement of a water-perfused silicone catheter which recorded pressures at 16 recording sites each spaced 7.5 cm apart in the unprepared colon for 24 h. These measures were compared with those obtained in another eight healthy volunteers in whom the catheter was placed to the caecum at colonoscopy in the prepared colon.

KEY RESULTS

The colonic motor responses to meals and morning waking, and the normal nocturnal suppression did not differ between the two groups, nor were the overall frequency, regional dependence nor extent of propagating sequences (PS) influenced by bowel preparation. Bowel preparation did result in a significant increase in the frequency of high amplitude PS (22 +/- 7 vs 8 +/- 4 HAPS/24 h; P = 0.003). Additionally, a number of the measures of spatiotemporal organization among consecutive PS (linkage among sequences and predefecatory stereotypical patterning) were significantly altered by bowel preparation.

CONCLUSIONS & INFERENCES

The overall frequency of PSs, the colonic responses to physiological stimuli such a meal and morning waking and nocturnal suppression, are not influenced by prior bowel preparation. However, investigators wishing to study HAPS frequency, or the more complex spatiotemporal relationships among consecutive PSs, should control for bowel preparation when making comparisons among study groups.

Phenotypic variation of colonic motor functions in chronic constipation

BACKGROUND & AIMS

Colonic motor disturbances in chronic constipation (CC) are heterogeneous and incompletely understood; the relationship between colonic transit and motor activity is unclear. We sought to characterize the phenotypic variability in chronic constipation.

METHODS

Fasting and postprandial colonic tone and phasic activity and pressure-volume relationships were assessed by a barostat manometric assembly in 35 healthy women and 111 women with CC who had normal colon transit (NTC; n = 25), slow transit (STC; n = 19), and defecatory disorders with normal (DD-normal; n = 34) or slow transit (DD-slow; n = 33). Logistic regression models assessed whether motor parameters could discriminate among these groups. Among CC, phenotypes were characterized by principal components analysis of these measurements.

RESULTS

Compared with 10th percentile values in healthy subjects, fasting and/or postprandial colonic tone and/or compliance were reduced in 40% with NTC, 47% with STC, 53% with DD-normal, and 42% with DD-slow transit. Compared with healthy subjects, compliance was reduced (P <or= .05) in isolated STC and DD but not in NTC. Four principal components accounted for 85% of the total variation among patients: factors 1 and 2 were predominantly weighted by fasting and postprandial colonic phasic activity and tone, respectively; factor 3 by postprandial high-amplitude propagated contractions; and factor 4 by postprandial tonic response.

CONCLUSIONS

Fasting and/or postprandial colonic tone are reduced, reflecting motor dysfunctions, even in NTC. Colonic motor assessments allow chronic constipation to be characterized into phenotypes. Further studies are needed to evaluate the relationship among these phenotypes, enteric neuropathology, and response to treatment in CC.

Design of a high-sensor count fibre optic manometry catheter for in-vivo colonic diagnostics

The design of a fibre Bragg grating based manometry catheter for in-vivo diagnostics in the human colon is presented. The design is based on a device initially developed for use in the oesophagus, but in this instance, longer sensing lengths and increased flexibility were required to facilitate colonoscopic placement of the device and to allow access to the convoluted regions of this complex organ. The catheter design adopted allows the number of sensing regions to be increased to cover extended lengths of the colon whilst maintaining high flexibility and the close axial spacing necessary to accurately record pertinent features of peristalsis. Catheters with 72 sensing regions with an axial spacing of 1 cm have been assembled and used in-vivo to record peristaltic contractions in the human colon over a 24hr period. The close axial spacing of the pressure sensors has, for the first time, identified the complex nature of propagating sequences in both antegrade (towards the anus) and retrograde (away from the anus) directions in the colon. The potential to miss propagating sequences at wider sensor spacings is discussed and the resultant need for close axial spacing of sensors is proposed.

Neuroanatomy and physiology of colorectal function and defaecation: from basic science to human clinical studies

Colorectal physiology is complex and involves programmed, coordinated interaction between muscular and neuronal elements. Whilst a detailed understanding remains elusive, novel information has emerged from recent basic science and human clinical studies concerning normal sensorimotor mechanisms and the organization and function of the key elements involved in the control of motility. This chapter summarizes these observations to provide a contemporary review of the neuroanatomy and physiology of colorectal function and defaecation.

Pathophysiology of evacuation disorders

This review details our contemporary knowledge of the mechanisms underlying evacuatory disorders. There is confusion concerning terminology and classification, which is based upon both an incomplete understanding of the multiple mechanisms involved in evacuation, and that current tests to investigate it are not physiological. Nevertheless, despite the need for more research, significant advances have been made and current assessments can direct therapy.

Pathophysiology of colonic causes of chronic constipation

Colonic sensorimotor dysfunction is recognized as the principal pathophysiological mechanism underpinning chronic constipation. This review addresses current understanding derived from both human and animal studies, with particular reference made to methods of investigation.

Function and dysfunction of the colon and anorectum in adults: working team report of the Swedish Motility Group (SMoG)

Symptoms of fecal incontinence and constipation are common in the general population. These can, however, be unreliably reported and are poorly discriminatory for underlying pathophysiology. Furthermore, both symptoms may coexist. In the elderly, fecal impaction always must be excluded. For patients with constipation, colon transit studies, anorectal manometry and defecography may help to identify patients with slow-transit constipation and/or pelvic floor dysfunction. The best documented medical treatments for constipation are the macrogols, lactulose and isphagula. Evolving drugs include lubiprostone, which enhances colonic secretion by activating chloride channels. Surgery is restricted for a highly selected group of patients with severe slow-transit constipation and for those with large rectoceles that demonstrably cause rectal evacuatory impairment. For patients with fecal incontinence that does not resolve on antidiarrheal treatment, functional and structural evaluation with anorectal manometry and endoanal ultrasound or magnetic resonance (MR) of the anal canal may help to guide management. Sacral nerve stimulation is a rapidly evolving alternative when other treatments such as biofeedback and direct sphincter repair have failed. Advances in understanding the pathophysiology as a guide to treatment of patients with constipation and fecal incontinence is a continuing important goal for translational research. The content of this article is a summary of presentations given by the authors at the Fourth Meeting of the Swedish Motility Group, held in Gothenburg in April 2007.

Spatio-temporal analysis reveals aberrant linkage among sequential propagating pressure wave sequences in patients with symptomatically defined obstructed defecation

Available evidence implicates abnormal colonic contractility in patients suffering from constipation. Traditional analysis of colonic manometry focuses on the frequency, extent and amplitude of propagating sequences (PS). We tested the hypotheses that the spatio-temporal linkage among sequential PSs exists throughout the healthy human colon and is disrupted during constipation. In eight patients with severe constipation and eight healthy volunteers, we recorded colonic pressures from 16 regions (caecum-rectum) for 24 h. Sequential PSs were regionally linked if the two PSs originated from different colonic regions but the segments of colon traversed by each PS overlapped. In order to determine whether this linkage occurred by chance, a computer program was used to randomly rearrange all PSs in time. Data were re-analysed to compare regional linkage between randomly re-ordered PSs (expected) and the natural distribution of PSs (observed). In controls the observed regional linkage (82.5 +/- 9.0%) was significantly greater than the expected value (60.5 +/- 4.3%; P = 0.0001). In patients the observed and expected regional linkage did not differ. The (observed - expected) delta value of regional linkage in controls was significantly greater than in patients (21.7 +/- 8.5%vs-2.3 +/- 7.0%; P = 0.01). Regional linkage among sequential PSs in the healthy colon appears to be a real phenomenon and this linkage is lost in patients with constipation. Regional linkage may be important for normal colonic transit and loss of linkage might have pathophysiological relevance to and provide a useful biomarker of severe constipation.

In-vivo demonstration of a high resolution optical fiber manometry catheter for diagnosis of gastrointestinal motility disorders

Fiber optic catheters for the diagnosis of gastrointestinal motility disorders are demonstrated in-vitro and in-vivo. Single element catheters have been verified against existing solid state catheters and a multi-element catheter has been demonstrated for localized and full esophageal monitoring. The multi-element catheter consists of a series of closely spaced pressure sensors that pick up the peristaltic wave traveling along the gastrointestinal (GI) tract. The sensors are spaced on a 10 mm pitch allowing a full interpolated image of intraluminal pressure to be generated. Details are given of in-vivo trials of a 32-element catheter in the human oesophagus and the suitability of similar catheters for clinical evaluation in other regions of the human digestive tract is discussed. The fiber optic catheter is significantly smaller and more flexible than similar commercially available devices making intubation easier and improving patient tolerance during diagnostic procedures.

American Neurogastroenterology and Motility Society consensus statement on intraluminal measurement of gastrointestinal and colonic motility in clinical practice

Tests of gastric, small intestinal and colonic motor function provide relevant physiological information and are useful for diagnosing and guiding the management of dysmotilities. Intraluminal pressure measurements may include concurrent measurements of transit or intraluminal pH. A consensus statement was developed and based on reports in the literature, experience of the authors, and discussions conducted under the auspices of the American Neurogastroenterology and Motility Society in 2008. The article reviews the indications, methods, performance characteristics, and clinical utility of intraluminal measurements of pressure activity and tone in the stomach, small bowel and colon in humans. Gastric and small bowel motor function can be measured by intraluminal manometry, which may identify patterns suggestive of myopathy, neuropathy, or obstruction. Manometry may be most helpful when it is normal. Combined wireless pressure and pH capsules provide information on the amplitude of contractions as they traverse the stomach and small intestine. In the colon, manometry assesses colonic phasic pressure activity while a barostat assesses tone, compliance, and phasic pressure activity. The utility of colonic pressure measurements by a single sensor in wireless pressure/pH capsules is not established. In children with intractable constipation, colonic phasic pressure measurements can identify patterns suggestive of neuropathy and predict success of antegrade enemas via cecostomy. In adults, these assessments may be used to document severe motor dysfunction (colonic inertia) prior to colectomy. Thus, intraluminal pressure measurements may contribute to the management of patients with disorders of gastrointestinal and colonic motility.

Determinants of postprandial flow across the human ileocaecal junction: a combined manometric and scintigraphic study

The relationships between ileocolonic motor patterns and flow have not been defined in humans. Utilizing simultaneous ileocolonic manometry and scintiscanning, we aimed to examine this relationship and test the hypotheses that ileal propagating sequences (PSs) underlie caecal filling, that caecal filling is a stimulus for proximal colonic PSs and that the ileocolonic junction (ICJ) regulates flow between the small and large bowel. In six healthy volunteers, a 5-m-long nasocolonic manometry catheter was positioned such that 16 recording sites, spaced at 7.5-cm intervals, spanned the ileum and proximal colon. Subjects were positioned under a gamma camera 30 MBq of (99m)Tc sulphur colloid was instilled, 22.5 cm proximal to the ICJ. Isotopic images were recorded (10 s per frame) and synchronized with the manometric trace. We identified 171 ileal PSs, 47 caecal PSs and 117 discrete episodes of caecal filling. Of the 117 episodes of caecal filling, 72% were associated temporally with ileal PSs. Conversely, 87% of ileal PSs were associated with caecal filling. Of the PSs originating in the caecum, 90% were temporally associated with caecal filling. We conclude that ileal PSs are highly propulsive and are the major determinant of episodic caecal filling and that caecal filling may be a major stimulus for caecal propagating sequences.

Twenty-four hour spatiotemporal mapping of colonic propagating sequences provides pathophysiological insight into constipation

Colonic propagating sequences (PS)s are a major determinant of luminal propulsion. A global appreciation of spatiotemporal patterning of PSs requires evaluation of 24 h pan-colonic recordings, a difficult task given that PSs are relatively infrequent events that are not uniformly distributed throughout the colon. Here we developed a means of space-time-pressure 'mapping' in a condensed format, 24 h of colonic recording in such a manner that readily permits an overall view of colonic antegrade and retrograde colonic PSs within a single figure. Such graphical representation readily permits appreciation and identification of aberrant patterns in severe constipation and may be an important clinical and research tool in the assessment of colonic motor disorders.

24-Hour colonic manometry in pediatric slow transit constipation shows significant reductions in antegrade propagation

BACKGROUND

The physiological basis of slow transit constipation (STC) in children remains poorly understood. We wished to examine pan-colonic motility in a group of children with severe chronic constipation refractory to conservative therapy.

METHODS

We performed 24 h pan-colonic manometry in 18 children (13 boys, 11.6 +/- 0.9 yr, range 6.6-18.7 yr) with scintigraphically proven STC. A water-perfused, balloon tipped, 8-channel, silicone catheter with a 7.5 cm intersidehole distance was introduced through a previously formed appendicostomy. Comparison data were obtained from nasocolonic motility studies in 16 healthy young adult controls and per-appendicostomy motility studies in eight constipated children with anorectal retention and/or normal transit on scintigraphy (non-STC).

RESULTS

Antegrade propagating sequences (PS) were significantly less frequent (P < 0.01) in subjects with STC (29 +/- 4 per 24 h) compared to adult (53 +/- 4 per 24 h) and non-STC (70 +/- 14 per 24 h) subjects. High amplitude propagating sequences (HAPS) were of a normal frequency in STC subjects. Retrograde propagating sequences were significantly more frequent (P < 0.05) in non-STC subjects compared to STC and adult subjects. High amplitude retrograde propagating sequences were only identified in the STC and non-STC pediatric groups. The normal increase in motility index associated with waking and ingestion of a meal was absent in STC subjects.

CONCLUSIONS

Prolonged pancolonic manometry in children with STC showed significant impairment in antegrade propagating motor activity and failure to respond to normal physiological stimuli. Despite this, HAPS occurred with normal frequency. These findings suggest significant clinical differences between STC in children and adults.

Pathophysiology of constipation in the older adult

This review provides information on the definition of constipation, normal continence and defecation and a description of the pathophysiologic mechanisms of constipation. In addition, changes in the anatomy and physiology of the lower gastrointestinal tract associated with aging that may contribute to constipation are described. MEDLINE (1966-2007) and CINAHL (1980-2007) were searched. The following MeSH terms were used: constipation/etiology OR constipation/physiology OR constipation/physiopathology) AND (age factors OR aged OR older OR 80 and over OR middle age). Constipation is not well defined in the literature. While self-reported constipation increases with age, findings from a limited number of clinical studies that utilized objective measures do not support this association. Dysmotility and pelvic floor dysfunction are important mechanisms associated with constipation. Changes in GI function associated with aging appear to be relatively subtle based on a limited amount of conflicting data. Additional research is warranted on the effects of aging on GI function, as well as on the timing of these changes.

Proximal colonic propagating pressure waves sequences and their relationship with movements of content in the proximal human colon

Abnormal colonic motor patterns have been implicated in the pathogenesis of severe constipation. Yet in health, the mechanical link between movement of colonic content and regional pressures have only been partially defined. This is largely due to current methodological limitations. Utilizing a combination of simultaneous colonic manometry, high-resolution scintigraphy and a quantitative technique for detecting discrete episodic flow, our aim was to examine the propulsive properties of colonic propagating sequences (PS) in the healthy colon. In six healthy volunteers a nasocolonic manometry catheter was positioned to record colonic pressures at 7.5 cm intervals from terminal ileum to the splenic flexure. With subjects positioned under a gamma camera, 30 MBq of (99m)Tc sulfur colloid was instilled into the terminal ileum, 22.5 cm proximal to the ileocolonic junction. Isotopic images were recorded (10 s/frame) and synchronized with the manometric trace. In the proximal colon we identified 137 antegrade PSs, of which 93% were deemed to be associated temporally with movements of luminal content. Low amplitude PSs, with component pressure waves between 2 mmHg and 5 mmHg, were as likely to be associated with colonic movements as higher amplitude PSs. As such there was no correlation between the amplitude of the PS and the temporal relationship with colonic movements. Within the proximal colon, 24 retrograde PSs were identified, 23 of which were associated with retrograde movements of colonic content. We conclude that proximal colonic PSs are highly propulsive and are a major determinant of proximal colonic flow.

Enteric glial cells and their role in gastrointestinal motor abnormalities: Introducing the neuro-gliopathies

The role of enteric glial cells has somewhat changed from that of mere mechanical support elements, gluing together the various components of the enteric nervous system, to that of active participants in the complex interrelationships of the gut motor and inflammatory events. Due to their multiple functions, spanning from supporting elements in the myenteric plexuses to neurotransmitters, to neuronal homeostasis, to antigen presenting cells, this cell population has probably more intriguing abilities than previously thought. Recently, some evidence has been accumulating that shows how these cells may be involved in the pathophysiological aspects of some diseases. This review will deal with the properties of the enteric glial cells more strictly related to gastrointestinal motor function and the human pathological conditions in which these cells may play a role, suggesting the possibility of enteric neuro-gliopathies.

Constipation

Chronic constipation is a common disorder manifested by a variety of symptoms. Assessments of colonic transit and anorectal functions are used to categorize constipated patients into three groups, i.e., normal transit or irritable bowel syndrome, pelvic floor dysfunction (i.e., functional defaecatory disorders) and slow transit constipation. 'Slow transit' constipation is a clinical syndrome attributed to ineffective colonic propulsion and/or increased resistance to propagation of colonic contents. Defaecatory disorders are caused by insufficient relaxation of the pelvic floor muscles or a failure to generate adequate propulsive forces during defaecation. Colonic transit is often delayed in patients with functional defaecatory disorders. Normal and slow transit constipation are generally managed with medications; surgery is necessary for a minority of patients with slow transit constipation. Functional defaecatory disorders are primarily treated with pelvic floor retraining using biofeedback therapy.