Ano-rectal motility in sick children

Early investigations into improving bowel and bladder function in fetal ovine myelomeningocele repair

INTRODUCTION

Fetal myelomeningocele (MMC) repair improves lower extremity motor function. We have previously demonstrated that augmentation of fetal MMC repair with placental mesenchymal stromal cells (PMSCs) seeded on extracellular matrix (PMSC-ECM) further improves motor function in the ovine model. However, little progress has been made in improving bowel and bladder function, with many patients suffering from neurogenic bowel and bladder. We hypothesized that fetal MMC repair with PMSC-ECM would also improve bowel and bladder function.

METHODS

MMC defects were surgically created in twelve ovine fetuses at median gestational age (GA) 73 days, followed by defect repair at GA101 with PMSC-ECM. Fetuses were delivered at GA141. Primary bladder function outcomes were voiding posture and void volumes. Primary bowel function outcome was anorectal manometry findings including resting anal pressure and presence of rectoanal inhibitory reflex (RAIR). Secondary outcomes were anorectal and bladder detrusor muscle thickness. PMSC-ECM lambs were compared to normal lambs (n = 3).

RESULTS

Eighty percent of PMSC-ECM lambs displayed normal voiding posture compared to 100% of normal lambs (p = 1). Void volumes were similar (PMSC-ECM 6.1 ml/kg vs. normal 8.8 ml/kg, p = 0.4). Resting mean anal pressures were similar between cohorts (27.0 mmHg PMSC-ECM vs. normal 23.5 mmHg, p = 0.57). RAIR was present in 3/5 PMSC-ECM lambs that underwent anorectal manometry and all normal lambs (p = 0.46). Thicknesses of anal sphincter complex, rectal wall muscles, and bladder detrusor muscles were similar between cohorts.

CONCLUSION

Ovine fetal MMC repair augmented with PMSC-ECM results in near-normal bowel and bladder function. Further work is needed to evaluate these outcomes in human patients.

Anorectal manometry in children with chronic functional constipation

BACKGROUND: The anorectal manometry is a very utilized and well recognized examination in children with chronic funcional constipation. The major manometric findings in these children are: anal hypotonia, anal hypertonia, paradoxal contraction of the external anal sphincter, decreased ability of internal anal sphincter to relax during rectal distension and alterations in rectal contractility, sensibility and compliance. AIMS: To evaluate the anal basal pressure and the relaxation reflex before and after standard treatment for a better understanding of the physiopathologic mechanisms involved in pediatric chronic functional constipation. METHODS: Anorectal manometry was performed before treatment on 20 children with chronic functional constipation aged 4 to 12 years and the results were compared to those obtained after standard treatment, with a good outcome. RESULTS: There was a reduction in anal basal pressure after treatment, but no differences were detected between the anorectal manometries performed before and after treatment in terms of amplitude and duration of relaxation, residual pressure, latency time, or descent and ascent angle. CONCLUSIONS: We conclude that the anal basal pressure decreased in children recovering from chronic functional constipation, but the standard treatment did not provide all the conditions necessary for the relaxation reflex of constipated children to return to the values described in normal children.

Total and segmental colonic transit time and anorectal manometry in children with chronic idiopathic constipation

BACKGROUND

Constipation is a frequent symptom in pediatric clinical practice, although the underlying pathogenesis is not fully understood. Estimating the colonic transit time may help identify subgroups of patients with different physiopathologic mechanisms.

METHODS

Thirty children with normal bowel habits and 38 children with chronic idiopathic constipation, aged 2 to 14 years, were studied. The total and segmental colonic transit times were estimated by administering multiple radiopaque markers for 6 days and performing a single abdominal radiograph on day 7. Anorectal function was evaluated using manometry with an Arhan probe.

RESULTS

The observed upper reference values were 19.02 hours for the right colon, 19 hours for the left colon, 32 hours for the rectosigmoid colon, and 45.7 hours for the total colon. Fifty percent of the children with chronic idiopathic constipation had colonic transit times within reference values, whereas 37% had left colonic and rectosigmoid delays and 13% had global delay in all colonic segments (colonic inertia). Paradoxic anal contraction was observed in 64% of the constipated children with distal delay but in none of the subjects with colonic inertia.

CONCLUSIONS

Estimating colonic transit time is a simple and noninvasive technique for classifying patients with constipation. Colonic inertia may be a manifestation of global motility dysfunction. Children with delayed distal colonic transits are more likely to have abnormal defecation dynamics.

Clinical and manometric postoperative evaluation of posterior sagital anorectoplasty (PSARP) in patients with upper and intermediate anorectal malformations

PSARP is currently the most widely-used surgical technique for surgical correction of high and intermediary anorectal malformations, but there is much controversy in the literature about the postoperative evaluation of these cases. We studied 27 cases of anorectal malformations operated with PSARP from clinical and manometric aspects in order to analyze: 1) fecal continence; 2) the relationship between fecal continence and the associated sacral anomalies and; 3) the relationship between the postoperative manometric evaluation and fecal continence. From the analysis of 27 cases of high and intermediary anorectal malformations, we concluded that: 1) fecal continence was achieved in 48.14 percent of the cases; partial fecal continence in 25.92 percent; and fecal incontinence in 25.92 percent of the cases; 2) the presence of fecal incontinence was directly related to the association of sacral anomalies and; 3) anorectal manometry is a useful test to evaluate the patients operated by PSARP, due to the existence of a relationship between the manometric results and the degree of fecal continence.

Factors determining outcome in children with chronic constipation and faecal soiling

To evaluate factors which might contribute to treatment failure in children with chronic constipation and soiling, we evaluated the history, physical findings, defecation dynamics, and anorectal function in 97 patients. We treated them with milk of magnesia, high fibre diet, and bowel training techniques and evaluated outcome at one year when 43% had recovered. Recovery rates were similar for boys and girls. Fifty seven per cent of the patients had not recovered. This group at the outset had more frequent soiling episodes, more severe constipation, were less likely to defecate water filled rectal balloons and to relax the external sphincter during defecation. In general girls had more severe constipation, abdominal pain, and a previous urinary tract infection than boys. Girls were more compliant during treatment and had less frequent soiling episodes at one year. Stepwise logistic regression showed that severe constipation, abnormal contraction of the external sphincter and pelvic floor during attempted defecation, and inability to defecate the 100 ml balloon in less than or equal to 1 min was significantly related to treatment failure. Defecation of smaller balloons, volumes for threshold of rectal sensation, critical volume and rectal contraction, and compliance with treatment could not predict treatment failure.

Manovolumetry: a new method for investigation of anorectal function

A new technique for manovolumetric investigation of rectoanal function allowing for simultaneous recording of rectal volume, anal pressure and external sphincter EMG in response to graded rectal distension was developed. Distension pressure was generated by a water column between two reservoirs. Volume was recorded as shifts of water between the reservoirs. Anal pressure was recorded with a cylindrical balloon and electromyographic activity of the external sphincter by means of a needle electrode. It could be shown that although reduction of preset pressure was minimal, this factor had to be taken into account when rectal compliance is high. The position of the patients during the investigation has to be defined, because rectal volume changed with body position. Pull through studies of anal pressure indicated low sensitivity to displacement of the cylindrical anal probe. A pressure adaptation to the anal probe during eight minutes was noted. Representative recordings of the anorectal response to different isobaric pressures are presented. The present system offers new possibilities for investigation of rectoanal physiology in man.

Encopresis and constipation in children

Chronic retentive constipation in children is common, often undertreated, and frequently resistant to standard treatment. A new understanding of abnormal defecation dynamics has evolved to complement the established medical behavior model of this condition. The primary care pediatrician is in an excellent position to facilitate prevention through counseling on normal bowel habits and early intervention. A comprehensive medical behavior intervention program can be supervised effectively by the pediatrician providing benefit to most patients. Those who are compliant with treatment and are resistant to intervention may benefit by extensive evaluation of anorectal dynamics and use of such teaching as biofeedback training.

Assessment of hindgut function in premature newborns

Anorectal manometry was performed on 32 small for dates and or preterm infants, using a micro-tip pressure transducer. A normal rectoanal reflex was observed in otherwise normal infants on the first day of life. During the neonatal period, hindgut function in these infants was studied longitudinally using the minimum excitation energy (MER) to elicit a rectoanal reflex. Data suggest that hindgut dysfunction (indicated by a significant increase in MER) develops prior to the onset of abdominal distension or necrotizing enterocolitis (NEC), rather than being present from birth. Consequently, this abnormality of function probably does not initiate the process that leads to NEC. This increase in MER may be a warning that the infant is about to develop abdominal distension or NEC.

Gastrointestinal transit time, frequency of defecation, and anorectal manometry in healthy and constipated children

Total gastrointestinal transit time (TGITT), frequency of defecation, and anorectal manometry were evaluated in 63 pediatric patients referred for chronic nonorganic constipation; in 39, segmental transit times of the right and left colon and rectum were also measured. TGITT was significantly longer in chronically constipated children than in matched normal controls. Although bowel frequency was highly significantly correlated with TGITT in patients with prolonged transit time, not all children with prolonged TGITT had reduced bowel frequency. Moreover, not all children with constipation had prolonged TGITT. In children with idiopathic chronic constipation, slowing of intestinal transit occurred most frequently at the level of the distal colon and rectum. Anorectal motility variables were not significantly different in children with functional chronic constipation and in normal children. Maximal resting and pressure and mean intrarectal distending volume causing threshold inhibition in constipated patients did not significantly differ from the control values. Therefore, anorectal manometry did not detect relevant motor abnormalities in constipated children.

Anorectal motility after surgery for spina bifida

Anorectal motility was studied in 93 children (aged 15 days to 16 1/2 years) who had undergone surgery for myelocele or meningomyelocele, and 80 controls, matched for age and sex. Mean resting pressure in the anal canal of patients was markedly decreased, particularly in the presence of incontinence, and unstable. The recording of a rectoanal inhibitory reflex both in the upper anal canal and at the anal margin was associated with the presence of fecal incontinence and motor disorders of the lower extremities. Patients could be divided into four groups according to manometric pattern: 1) those with normal recordings (incontinence in 63 per cent), 2) those with spontaneous intermittent relaxations of the upper anal canal and simultaneous rectal contractions (incontinence in 91 per cent), 3) those with normal manometry except for unstable upper anal canal pressure (incontinence in 92 per cent), and 4) those with absence of the rectoanal inhibitory reflex and hypotonic anal canal (patients too young to appraise continence, all under 2 years).

Radiologic diagnosis of Hirschsprung's disease utilizing rectosphincteric reflex

Artificial balloon distension of the rectum caused a reflex opening of the anal canal as seen during barium enema in 10 out of 10 normal children and in 7 of 7 children with idiopathic constipation. Reflex opening of the anal canal was not observed in any of 15 children with proven Hirschsprung's disease. This lack of response was independent of the length of aganglionosis or previous diverting colostomy and corresponded to the fact that on manometric study the intraluminal pressure of the anal canal fell in normal children but not in the children with Hirschsprung's disease. This finding greatly improves the reliability of barium enema in the diagnosis of Hirschsprung's disease.

Abnormal and sphincter response in chronically constipated children

Using a strain gauge, we measured anal sphincter function in 116 chronically constipated and 18 healthy children. Eighteen constipated children were re-evaluated two months later (receiving laxative), and 15 were again studied seven to 12 months later. The anal resting tone varied along the length of the anal canal and was highest at 1 to 1.5 cm from the anal verge. This region was used to study the resting motor activity of the internal anal sphincter, the amplitude of the rectosphincteric reflex after 30 and 60 ml rectal distension, and the rectosphincteric reflex threshold. The mean and resting tone was significantly lower in constipated than in control children (P less than 0.001), but normalized in patients who recovered. Resting motor activity of the internal anal sphincter and the amplitude of RSR were significantly lower in constipated patients than were the corresponding values in control children (P less than 0.001), and remained lower during and after treatment, even in patients who recovered. The length of the anal canal and the RSR threshold were comparable in control and constipated children. Thus, the basic problem in chronically constipated children appears to be an abnormal internal anal sphincter, which is weaker and less responsive to rectal distension than in nonconstipated children.

Quantitative analysis of anorectal pressures in Hirschsprung's disease

Anorectal motility was investigated in 146 children with Hirschsprung's disease and 89 normal control subjects. Pressures were recorded in the rectum and anal canal at rest and during rectal distention. The rectoanal inhibitory reflex was absent in all but four patients. Intraluminal rectal pressure was higher than normal (16.5 vs. 14.6 cm H2O, P less than 0.03), with more frequent (41 per cent vs. 18 per cent, P less than 0.01) pressure waves. In the upper anal canal, there were more frequent (62 per cent vs. 18 per cent, P less than 0.001) spontaneous variations of pressure of lower frequency (9.5 vs. 12.8 cycles/min P less than 0.001) and greater amplitude (5.2 vs. 3.6 cm H2O, P less than 0.001) than normal. The rectoanal contractile reflex occurred in 47 per cent of the patients but in only 21 per cent of the control subjects (P less than 0.001). Aganglionosis was associated with the presence of a rectoanal inhibitory reflex in three patients. This study confirms the value of anorectal manometry in diagnosing Hirschsprung's disease in a large group of patients, and demonstrates other abnormalities that may be useful in cases in which histologic and manometric data are in conflict.

Accuracy of the manometric diagnosis of Hirschsprung's disease

In a 3-yr period, 229 examinations were carried out in infants and children. These were sub-divided into five groups according to age. There were 10 false positive and 8 false negative results, an overall not unreasonable record of 7.8% errors. However, in the neonatal group, there were as many as 26% errors and thus the test in this group was considered to be highly inaccurate. The older the infant or child, the less errors in diagnosis occurred. Possible reasons for errors are pointed out and comparisons are made with other series.

Viscoelastic properties of the rectal wall in Hirschsprung's disease

Viscoelastic properties of the rectal wall were compared with Hirschsprung's disease. The elasticity of the rectal wall after accomodation to distension was found to be significantly greater (P less than 0.001) in patients, and the time taken by the rectum to accomodate was also found to be longer (P less than 0.001). The increased elasticity correlated well with severity of the illness, but none of the parameters correlated with length of aganglionic segment. Measuring elastic properties of the rectal wall may help to assess the severity of illness in patients with Hirschsprung's disease.

Control of the internal anal sphincter (manometric study with human subjects)

Manometric studies of the functions of the internal anal sphincter were performed in 73 children. Twenty-one out of these patients were normal subjects, the others had neurological lesions either central (sacral meningocele, dorsal cord transections) or peripheral (Hirschsprung's disease). It was found that the functions of the internal sphincter do not depend upon mechanical factors and are subject to nervous control. The pathways for control of the basal sphincteric tone are discussed. It is likely that this tone depends not only of the sympathetic pathways, but also of fibers of the sacral outflow. It is shown that the recto-anal inhibitory reflex is specific and independent of peristalsis. Arguments are given to prove that this reflex is an activity proper to the intra-mural plexus which is, however, subject to and regulated by the sacral cord.

Manometric studies of anorectal disorders in infancy and childhood: an investigation of the physiopathology of continence and defaecation

Anorectal manometry was performed on 126 infants and children with anorectal dosorders. In addition, 14 normal children were studied. Pressure measurements were taken with two perfused open-tip catheters. The activity of the external and internal balloon was used to distend the rectal ampulla with air.

Manometric assessment of continence after surgery for imperforate anus

Of 49 children with imperforate anus, 23 underwent an abdominoperineal procedure for a high and seven for a low maliformation, 17 had a perineoplasty for a low and two for a high malformation. In each subject, rectal and anal sphincteric resting pressures were studied at least 1 yr after surgery. Of 30 subjects who had undergone an abdominoperineal procedure, eight were continent in contrast to 15 out of 19 patients who had had a perineoplasty (p less than 0.001). In patients who had undergone an abdominoperineal procedure, the rectal motility was of the colonic type, with waves of higher amplitude and lower frequency (p less than 0.01) than in the normal rectum in 23 cases and in most of these, peristalsis was recorded down to the anal margin. Incontinence was most frequently associated with abnormally short anal resistance, low anal pressure, reduced sensibility, weak voluntary contraction and absence of rectoanal inhibitory reflex. In the group of patients who underwent perineoplasty, continence was associated with normal mechanical parameters and normal physiologic behavior of the anal sphincter.