Maturation of the rectoanal response in premature and perinatal infants

Maturation of the Rectoanal Response in Premature and Perinatal Infants By Yasuo Ito, Patricia l Twenty

unselected

K. Donahoe,

premature

and

and W. Hardy

Hendren

perinatal infants, and 40 older infants and children with chronic constipation were investigated manometrically. Anorectal pressure studies were found to be a safe and reliable screening method for

Rex requires further evaluation by tissue diagnosis. A normal reflex does not occur in premature or perinatal infants in whom matumtional age (gestational age plus age after birth) has yet to reach 39 wk, and who weigh less than 6 lb.

Hirschsprung’s disease. Many unnecessary deep and superficial rectal biopsies were avoided by recording a normal rectoanal response. Failure to record a normal re-

INDEX WORDS: Hirschsprung’s disease; oganglionic megacolon; chronic constipotion.

B

ALLOON MANOMETRY is a reliable, noninvasive technique for the study of Hirschsprung’s disease. However, previous investigator@ have noted limitations in the use of this diagnostic tool in the newborn baby. We wish to present studies in premature and perinatal infants which determine the limits of reliability of anorectal manometry in this age group, and to establish the relationship of maturation and weight to the appearance of the normal rectoanal response. In addition, we have studied older constipated children, comparing the results of anorectal pressure studies with superficial and deep biopsy. The object of this second group is to determine if anorectal pressure studies are more reliable than the superficial punch biopsy, and to determine if a positive rectoanal response will indicate that no other studies are needed for the diagnosis of Hirschsprung’s disease in this symptomatic group. MATERIALS

AND

METHODS

Subjects Unselected newborn infants were studied ranging in Group I-Premature and Newborn Infants. age from the premature of 28 wk gestation to the full term baby of 40 wk gestation. Each of these babies were seen initially at some time between the first day of life and 6 wk of age. Selected babies were restudied at varying intervals thereafter. Their weights ranged from l-4 kg. Twenty infants were included in this group. Group II-The Older Constipated Child. Chronically constipated older infants and children were studied ranging in age from 1 mo-19 yr. Manometric pressures were then correlated with the results of either superficial or deep rectal biopsy in order to establish or to rule out the diagnosis of Hirschsprung’s disease. Forty subjects were included in this group.

From the Division of Pediatric Surgery and the Pediatric Surgical Research Laboratory, Massachusetts GeneraI Hospital, and the Department of Surgery. Harvard Medirai School, Boston, Mass. Presented before the 25th Annual Meeting of the American Academy of Pediatrics. Surgical Section, Chicago, Illinois, October 17-19. 1976. Address reprint requests to: Patricia K. Donahoe, M.D., Division of Pediatric Surgery, Massachusetts General Hospital, 32 Fruit Street, Boston, Mass. 02114. D I977 by Grune & Stratton, Inc.

Journal of Pediatric Surgery, Vol. 12, No. 3 (June), 1977

477

ITO, DONAHOE,

478

Sph oni

AND

HENDREN

mt, vent

sph aniext.

\

I

Recta1 probe

Fig. 1. Stainless steel double lumen waterfilled manometric probe inserted in rectum with sensor membrane at the anal canal. The rectal balloon is advanced through the inner lumen to provide stimulus. In normals inflation of the balloon causes relaxation of the anal sphincter. The sphincter does not relax, however, in Hirschsprung’s disease nor when infants are less than 39 wk gestational age or below 6 lb weight.

Instruments Double lumen stainless steel manometric probes* (Fig. 1) of three sizes for premature, infants, and adults were used (Yufu Itonaga Co., Ltd., and given to us by Drs. Keizo Katsumata and Jotaro Yokoyama of Keio University, Tokyo, Japan). The efficacy of these instruments has been demonstrated both experimentally and clinically.3’4 The entire system including probe, membrane sensor, and transducer? was closed and waterfilled. A multiple channel recorder1 was used for older infants and children. A small portable recorder1 was used for newborn infants so that measurement could be done at the incubator.

Techniques Unprepared, awake subjects were placed on their sides in Sim’s position. was inserted so that the pressure recording membrane (Fig. 1) lay across

The manometric probe the anal canal, i.e., the

internal and external sphincters. The stimulus balloon was advanced through the inner lumen of the probe to a point between 3-8 cm proximal to the anal verge, depending upon the age of the patient and the size of the ampulla. A stimulus was delivered to the balloon consisting of a volume of air between 3cc for the premature infant to 3Occ for the adult. The choice of volume for each individual was critical since the contour of the tracing of the rectoanal response varies directly with the volume of the stimulus balloon. Figure 2 demonstrates the increasing depth of the rectoanal response as the volume of the balloon increases. A positive rectoanal response consisted of three successive pressure falls, each immediately following upon the balloon stimulus. Most of the children were awake, without anesthesia or premeditation. A few children were examined before surgery under light Stage II anesthesia. In the awake child complete cooperation and relaxation is required to elicit normal rectoanal response.

*Yufu Itonaga, Ltd., Tokyo, Japan. tPressure Transducer, Model #267AC, Sanborn Corporation, Waltham, Mass. IRecorder, Model #350 and x301, Sanborn Corporation, Waltham, Mass.

RECTOANAL

479

RESPONSE

RECTAL STIMULUS

20ml

I

I I

I

I

20 mmHg

I I

H

5sec

25i-d

Fig. 2. Pmssure response or a function of the balloon volume. Increased tilling of bolloon or 0 stimulus to rectum causes 0 gmoter pmssura drop, i.e., more relaxation, at the onol sphincter.

30ml

RESULTS

The findings show that total maturation age (Fig. 3) rather than age after birth, and weight are important factors in obtaining a positive rectoanal response. Those infants who are greater than 39 wk total maturation age (gestation age plus age after birth) when tested, and who weight more than 2.7 kg (6 lb) gave a positive response. The single exception to this was an infant with Hirschsprung’s disease who, as expected, did not record a rectoanal response at 3 kg and 42 wk maturational age. Those infants younger than 39 wk total l

Positive

Reflex

o

No Reflex

A

Hirschsprung’s

I

I

Kg 4

33

32

34

36

38

MA TURA TIONAL

( Geslof/onat

age

+

40 AGE Age

42

44

f WEEKS/ affer birfh !

46

pig. 3. The mctoonol response OS a function of motumtionol age and weight. Only infonts older thon 39 wk or heavier than 6 lb hod positive nctwnol response.

ITO, DONAHOE,

480

AND HENDREN

Gest. Age (weeks) 28

Or Weight

ItOmmHg tosac

i.7

Kg

H

33

3.0 Kg

42

14

7

I HSseC

I

20mmHg

I-

Fig. 4. Multiple studies on a premature infant born at 28 wk and studied at 6, 14, and 17 wk of age. Note negative initial weakly positive second exam, exam, and normal third exam at age 17 wk (45 wk gestotional oge and weight 4 kg).

(451 4.0 Kg

maturational age, even if they were 6 wk old at the time of testing, did not give a rectoanal response. Fischer’s exact test calculates that the level of significance is .00025. Thirty-nine weeks was chosen after data was collected and therefore somewhat overstates the level of significance. Two small-for-dates infants older than 39 weeks maturational age and weighing less than 6 lb did not demonstrate a rectoanal response. Although this number is small and cannot be analyzed statistically, we believe it represents an important trend. We observed that as the premature infants mature, the anorectal response appears when the baby reaches the equivalent of full term gestation (Fig. 4b). The contour of the rectoanal response approaches normal as the infants further mature. This is shown by the sequential pressure studies of a single infant illustrated in Fig. 4. A number of older children were studied because of symptoms of chronic constipation. These children ranged in age from 1 mo after full term to 19 yr. Thirty-five of 40.(Table 1) had a normal rectoanal response, thereby ruling out Hirschsprung’s disease. Further biopsy studies or clinical observation were done to confirm these interpretations. Five had no fall in rectoanal pressure. In Table 1. Recta-Anal Response in Chronic Constioation Reflex Present

R&x

(35) Normal

Hirschsprung’s

Hirschsprung’s

Ganglion

A positive Disease record

tissue but

rectoanol diagnosis. 2 did

meaningful

not.

response Of These

pressures. .

rules

5 older 2 were

out

subjects tense

Normal

3

35

0

further

Absent (5)

Hirschsprung’s

disease.

2 (-) A

Ganglion

negative

tested

who

hod

o

negative

patients

who

did

not

relax

rectoanal

response, abdominal

3

(+)

response hod

muscle

requires

Hirschsprung’s well

enough

to

RECTOANAL

481

RESPONSE

three of this group with no rectoanal response, the diagnosis of Hirschsprung’s was made by rectal biopsy. Two others without rectoanal response were shown to have ganglion cells on rectal biopsy and Hirschsprung’s disease was thereby ruled out (Table 1). Of the 35 with a normal manometric response, 16 had either superficial or deep biopsy which showed the presence of ganglion cells. Four-other children had no ganglion cells on superficial biopsy, but the rectoanal response had such a normal contour that the patients were treated conservatively and responded. It is likely that the mucosa biopsy specimens were too small to allow definite interpretation for presence of ganglion cells. The remainder of the patients were not biopsied but were followed after conservative treatment to which they rapidly responded. DISCUSSION

Rectoanal manometry is now widely appreciated as a reliable, safe, noninvasive screening method for the diagnosis of Hirschsprung’s disease. Our studies with the older constipated child confirmed the original studies of Schuster et al.’ and Tobon et al.,6 Nixon et al.,‘,’ and Katsumata et al.,* and have further established the reliability of this modality in the older infant and child. This study indicates unequivocally that a normal rectoanal response can safely rule out Hirschsprung’s disease as a cause of distention and constipation. However if the rectoanal response is absent, then further studies must be done to establish a diagnosis with certainty, especially in the small infant. Rectoanal pressure studies, which are equally as reliable as the superficial rectal biopsy, have replaced the latter as the initial screening test for the chronically constipated child in our department. After a normal rectoanal tracing is demonstrated, then the child is placed on a regimen of enemas, cathartics, and bulk laxatives. Those children who do not respond after adequate trial are considered for a posterior anoplasty at which time a confirmatory biopsy is performed. We suggest the following considerations when employing anorectal manometry. 1) This technique is difficult in a child from l-4 yr of age; they usually require some form of premeditation. 2) Premeditation requires observation of the infant and, therefore, makes the technique less feasible in the office or outpatient setting. 3) Complete cooperation and relaxation are required in order to obtain an ideal rectoanal tracing. The tense patient will often increase intraabdominal pressure and thereby completely override the normal rectoanal drop after intralumenal stimulus. This same patient may also dislodge the probe by retracting the external and internal sphincters. 4) The addition of a side arm manometer to measure pressure as air is introduced into the stimulus balloon, may be helpful in selecting the proper stimulus size for each infant. This study sought primarily to define when the rectoanal response first becomes apparent in the premature and newborn infant, so that manometry can be applied with some reliability to this younger age group, where diagnosis by other means may introduce some morbidity. The rectoanal response in this small series of twenty premature and perinatal patients did not appear until the infants reached 39-40 weeks maturational age. This time correlates with the

482

ITO, DONAHOE,

AND HENDREN

*maturation of the myenteric ganglion cells which are said to morphologically mature from a bipolar to a multipolar form at this age.9 Thus, full maturation of the infant may be necessary to allow complete development of the ganglion cells, as well as complete formation of the reflex arch, the two important parameters of the rectoanal response. These results illustrate that total maturational age is the

important parameter in predicting the appearance of a normal rectoanal response, rather than age after birth as advocated by previous investigators.‘T2 In addition, we have observed absence of the normal rectoanal reflex in “smallfor-dates” infants who are older than 39 wk gestation but weigh less than 2.7 kg (Fig. 3), although others believe that birth weight is not critical in the maturation of the reflex.2v9The presence in this small group of perinatal infants of other abnormalities such as respiratory distress syndrome,‘O apnea, necrotizing enterocolitis, galactosemia, cardiac defects, or esophageal stricture, had no bearing on the appearance of the rectoanal response, except as these defects were associated with prematurity or low birth weight. As a result of this study we would suggest that rectoanal manometric studies be reserved for those babies who exceed 39 wk maturation and who weigh more than 6 lb. Again, as in the older child, the presence of a normal rectoanal response means that Hirschsprung’s disease can be ruled out, and the absence of the response requires further study to make a definitive diagnosis. Invasive techniques then can be reserved for a much smaller group of infants, rather than placing the larger group at risk. ACKNOWLEDGMENT We wish to acknowledge the kindness of Drs. Samuel H. Kim. Daniel Shannon, Dorothy Kelly, David Todres, and Fergus Moylan for allowing us to study their patients. We thank Dr. John Gilbert for providing the statistical analysis of this work. The Resident Prize Essay Award was given to Dr. Ito for this study.

of the Surgical

Section

of the American

Academy

of Pediatrics

’ REFERENCES

I. Howard ER, Nixon HH: Internal anal sphincter. Observations on development and mechanism of inhibitory responses in premature infants and children with Hirschsprung’s disease. Arch Dis Child 43:569-578, 1968 2. Holschneider AM, Kellner E, Streibl P, et al: The development of anorectal continence and its significance in the diagnosis of Hirschsprung’s disease. J Pediatr Surg 11:151l156, 1976 3. Ito Y, Namba S, Yokoyama J, et al: Measurement of anorectal pressure: Comparison between open tip method and balloon method. J Jpn Sot Ped Surg 9:73, 1973 4. Namba S, Ito Y, Yokoyama J, et al: A manometric study in the differential diagnosis of constipation. J Jpn Sot Coloproctol 27:143, 1974 5. Schuster MM, et al: Simultaneous

Hookman P, Hendrix TR, manometric recording of

internal and external anal sphincter reflexes. Bull Johns Hopkins Hosp Il6:79-88, 1965 6. Tobon F, Reid NCRW, Talbert JL, et al: Nonsurgical test for the diagnosis of Hirschsprung’s disease. New Eng J Med 278: l88- 194, 1968 7. Aaronson I, Nixon HH: A clinical evaluation of anorectal pressure studies in the diagnosis of Hirschsprung’s disease. Gut 13: 138-46, 1972 8. Katsumata K, Yokoyama J, Ito Y, et al: Diagnosis of Hirschsprung’s disease. Geka (Surgery) 37:1413-1424, 1975 9. Smith 9: Prenatal and postnatal development of the ganglion cells of the rectum and its surgical implications. J Pediat Surg 3:386-394, 1968 10. Dunn PM: Intestinal obstruction in the newborn with special reference to transient functional ileus with respiratory distress syndrome. Arch Dis Child 38:459-467, 1963