Anorectal manometry in premature infants

Comparison between perfusion and balloon techniques for performing anorectal manometry in children with intestinal constipation

INTRODUCTION

Two anorectal manometry techniques have commonly been utilized: the perfusion technique and the balloon technique.

PURPOSE

To compare both techniques in children with intestinal constipation who had not undergone surgical treatment for its correction.

METHODS

Thirty-nine children aged between four and fourteen years underwent anorectal manometry using both techniques at random. Resting pressure, pressure response to voluntary contraction, coughing and perianal stimulation, maximum pressure on the anal canal pressure curve, and presence of rectosphincteric reflex were registered and submitted to statistics. Vectorgraphy of the sphincter muscle complex was obtained by perfusion technique.

RESULTS

The statistical comparison between the techniques revealed statistically significant differences in resting pressure (p=0.041), pressure response to voluntary contraction (p=0.026) and maximum pressure within the pressure curve (p=0.010). The rectosphincteric reflex was demonstrated in 21 patients by both techniques.

CONCLUSIONS

The perfusion technique presented greater sensitivity in the following parameters: resting pressure, pressure response to voluntary contraction and maximum pressure within the pressure curve. The methods studied are equivalent regarding the measurement of pressure responses to coughing and perianal stimulation and the investigation of rectosphincteric reflex.

Posterior sagittal anorectoplasty in anorectal anomalies: clinical, manometric and profilometric evaluation

CONTEXT AND OBJECTIVE

Anorectal malformations comprise a spectrum of anomalies that continue to be difficult to treat, even today. The aim was to evaluate the fecal continence of children who underwent posterior sagittal anorectoplasty due to anorectal malformations, via computerized anorectal manometry and profilometry.

DESIGN AND SETTING

Prospective study at Universidade Federal de São Paulo.

METHOD

82 patients (56.1% boys; 43.9% girls) of mean age 85.5 months were evaluated. They were divided into continent, partially continent and incontinent groups. Age, sex, manometric variables and profilometric parameters were studied. The results were statistically analyzed.

RESULTS

Among the 82 patients, 37.8% were continent, 25.6% were partially continent and 36.6% were incontinent. The overall mean resting pressure was 22 mmHg, and the means for the continent, partially continent and incontinent groups were, respectively, 30.7 mmHg, 23 mmHg and 14.7 mmHg. The overall mean pressure response to voluntary contraction was 56 mmHg, and the means for the groups were 65.4 mmHg, 55.8 mmHg and 46.6 mmHg, respectively. The rectosphincteric reflex was absent in 82.9% of the cases. In the profilometry analysis for all patients together, blue (20 to 50 mmHg) and yellow (50 to 80 mmHg) were predominant, and there was a similar distribution for the continent and partially continent patients. However, among the incontinent patients, green (< 20 mmHg) and blue prevailed.

CONCLUSIONS

Manometric and computerized profilometric analyses were an excellent method for postoperative evaluations on patients with intermediate and high anorectal anomalies, and for therapeutic planning.

Maturation of the rectoanal inhibitory reflex in very premature infants

OBJECTIVE

To characterize anal sphincter function in very premature infants < or =30 weeks' postmenstrual age (PMA) and to evaluate the time of maturation of the rectoanal inhibitory reflex (RAIR) by using a sleeve catheter.

STUDY DESIGN

Anorectal manometry was performed in 16 healthy neonates (nine girls) with a mean PMA of 29 weeks (range, 27-30 weeks) and a birth weight of 640 to 1590 g (median, 1220 g) with a micromanometric assembly (outer diameter, 2.0 mm). The assembly incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and four side holes recorded anal and rectal pressures. Rectal distention was performed with direct air insufflation to elicit the RAIR.

RESULTS

The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 24.5+/-11.4 mm Hg, 6.5+/-4.8 mm Hg, and 11.1+/-2.3/min, respectively. A normal RAIR could be elicited in 13 (81%) infants studied. In two infants, the RAIR could not be elicited because of a low anal sphincter pressure of only 5 mm Hg. In the other child, no RAIR was seen despite the repeated insufflation of at least 5 mL of air.

CONCLUSION

The majority (81%) of premature infants older than 26 weeks' PMA have normal anorectal pressures and a normal RAIR.

Characterization of anorectal pressure and the anorectal inhibitory reflex in healthy preterm and term infants

OBJECTIVES

To evaluate anorectal motor function in healthy premature and term infants with the use of micromanometric techniques.

STUDY DESIGN

Anorectal manometry was performed in 22 healthy neonates (9 female) with a mean postmenstrual age of 32 weeks (range, 30 to 38 weeks) with a micromanometric anorectal assembly (od 2.0 mm). The assembly incorporated a 2-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and 4 sideholes recorded anal and rectal pressures. Rectal distension was performed with a latex balloon or direct air insufflation to elicit the anorectal inhibitory reflex (AR).

RESULTS

The mean anal sphincter pressure, rectal pressure, and rhythmic wave frequency were 40 mm Hg (range, 7 to 65 mm Hg), 11 mm Hg (range, 1 to 27 mm Hg), and 10/min (range, 8 to 14/min), respectively. A normal AR could be elicited in 21 of the 22 infants studied.

CONCLUSION

An anorectal micromanometric sleeve catheter is suitable for use in evaluating anorectal pressures in preterm and term neonates. Insufflation of air without the use of a balloon to elicit the AR is reliable and suitable for use in infants <34 weeks. Premature infants older than 30 weeks' postmenstrual age have normal anorectal pressures and a normal AR.

Technical improvement for anorectal manometry in newborns

A modification of the anorectal manometric technique has been devised to improve its accuracy in 31 low-weight newborn and premature infants. The characteristics of the probes used allowed long recording sessions without any sedation of patients. The pressure records fit well the classically accepted requisites. All recordings showed spontaneous fluctuating waves and increased mean pressure in the aboral direction. The anorectal reflex was observed in all cases. Clear reflex waves were recorded in the most caudal third of the anal canal. In this zone the recording showed more distinct features with respect to fluctuation and relaxation waves than those located in more proximal parts. The validity of this technique is unquestionable from the view of the reliability of the recordings independent of the weight, gestational age, and birth age of the infants.

Anal tonometry in the neonatal period for the diagnosis of Hirschsprung's disease

A double balloon technique was used for anal tonometry in 22 infants. The weight was less than 2,500 g in 10 of the infants. Ileus or delayed passage of meconium was seen in 9 infants. Thirteen infants had not revealed any symptoms of intestinal obstruction during the first week of life. In all cases, except one, it was possible to demonstrate reflexes from the internal anal sphincter. In 18 infants normal curves were registered from the internal anal sphincter. None of these developed Hirschsprung's disease. In 3 infants a pathological pattern of contractions of the internal anal sphincter was demonstrated. Two of them proved to have Hirschsprung's disease. In the third case normal reflexes were registered after one year. Possibly the innervation of rectum and the internal anal sphincter was disrupted during the neonatal period in connection with enterocolitis and ileus, thus representing a reversible case of achalasia.

Diagnosis of Hirschsprung's disease by anorectal manometry

Anorectal manometry was performed in 48 Japanese children with Hirschsprung's disease and 61 normal children. The resting pressure of the rectum and anal canal was not significantly different between these groups of subjects. The frequency of rhythmical contractions of the anal canal of patients was significantly lower than for the normal subjects, but the frequencies overlapped considerably. Therefore, the frequency is an inadequate indicator for identifying these patients. Conventional manometry elicited a distinct rectoanal relaxation reflex from 90% of the normal children, and the rate increased to 98% when indistinct reflexes were regarded as positive. Indistinct reflexes often occur in neonates, possibly because the constriction of the anal canal is weak. However, when prostaglandin F2 alpha was intravenously administered during the examination, all ambiguous reflexes became distinct. Of patients with Hirschsprung's disease, 4% had a distinct reflex and 19% an atypical one. Most of the atypical reflexes were regarded as being artifacts and were mostly attributed to distension by a balloon. In these patients, the reflex was abolished in case of examination with electric stimulation or stimulation with cold water, procedures which do not dilate the rectum. Moreover these atypical reflexes did not fit the criteria for the normal rectoanal relaxation reflex prepared by the Japan Study Group of Pediatric Intestinal Manometry. The use of electric stimulation, cold water, or intravenously administered prostaglandin F2 alpha improves reliability of the conventional anorectal manometry. A clear and accurate definition of the normal reflex should aid in excluding the atypical reflex.

Manometric diagnosis of Hirschsprung's disease in the neonatal period

A newly designed semiconductor manometer was assembled for anorectal manometry in the neonatal period. Sixty apparently healthy neonates and 17 patients who presented gastrointestinal obstructive symptoms were examined by the eighth day of life. All 60 apparently healthy neonates showed a normal fluctuating wave and rectoanal reflex. Prematurity and postnatal age do not influence the normal rectoanal reflex. Among 17 patients, 5 were diagnosed as having Hirschsprung's disease based on absence of the reflex. There were no false negative or false positive results among these cases. It appears that anorectal manometry could be a reliable diagnostic test of Hirschsprung's disease even in the neonatal period.