A Manometric Assessment of Anorectal Pressures and its Significance in the Diagnosis of Hirschsprung's

Disease and Idiopathic Megacolon

Naomi IWAI, Shuhei OGITA, Makoto KIDA, Bunzo NISHIOKA, Yoshihiro FUJITA and Susumu 2VIAJIMA

ABSTRACT: Anorectal manometric studies were performed on nine patients with Hirschsprung's disease and ten patients with idiopathic mega- colon for the purpose of differentiation, comparing with those of the normal subjects. The anorectal reflex was absent in all nine of the patients with Hirschsprung's disease while in all of ten patients with idiopathic mega- colon rectal distension produced a relaxation in the anal canal like that of the normal subjects. Manometric studies proved to be a reliable and non- invasive technique for the diagnosis of Hirschsprung's disease and were of particular value as simple screening tests in patients with a clinical sug- gestion of this disease.

The manometric studies of the patients with Hirschsprung's disease or idiopathic megacolon in the present series also demonstrated that the pro- nounced internal sphincter contraction combined with a total absence of reflex relaxation or an inadequate response of the sphincter to rectal disten- sion might be responsible for the obstructive symptoms in these diseases.

KEY W O R D S : Hirschsprung's disease, idiopathic megacolon, anorectal manometry, anorectal pressure.

INTRODUCTION

S C H N A U F E R et al. 7 and Lawson and Nixon 6 reported at the same time in 1967 that the anorectal reflex was absent in cases of Hirschsprung's disease. Since then, anorectal manometric studies have been appreciated as a reliable and safe method for the diagnosis of Hirschsprung's disease. In our clinic, this manometric test has been in routine clinical use for over two years to evaluate anomalies in congenital anorectal discorders and to assess the state of fecal continence postoperatively. We a previously reported the results of manometric assessment of postoperative continence in patients following reconstructive surgery for imperforate anus.

The purpose of this paper is to describe our experience in performing manometric studies on patients with Hirschsprung's disease or idiopathic megacolon, comparing with that of normal subjects.

MATERIALS AND METHODS

Patient Material Manometric studies were performed on 9 patients, aged 4 days to 12 years, with

From the First Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan

JAPANESE JOURNAL OF SUROERY, VOL. 9, No. 3, pp. 234-240, 1979

Volume 9 Number 3 Anorectal Manometry in Hirschsprung's Disease and Idiopathic Megaeolon 235

Hirschsprung's disease (7 males and 2 females), 10 patients, aged 2 months to 19 years, with idiopathic megacolon (6 males and 4 females) and 35 normal subjects, aged 2 to 6 years (27 males and 8 females) as controls.

In all patients with Hirschsprung's disease and 3 of the 10 patients with idiopathic megacolon, the diagnosis was established on the basis of clinical evaluation and barium enema studies and confirmed by the presence or absence of ganglion cells in Auerbach's plexus on rectal muscle biopsy. In the additional 7 patients with idiopathic megacolon, the diagnosis was established by clinical symptoms and barium enema studies, which revealed a large rectum and colon, dilatation extending down to the anus, and an absence of the transition segment. Accordingly, rectal muscle biopsy was not performed in these cases.

Method of Study The manometric studies were performed without special bowel preparation. This

study was done principally without anesthesia, however general anesthesia was required on restless children at the time of examination (Ketamine chloride 5 mg/kg by intra- muscular injection or thiopental sodium 30 mg/kg per rectum). It was found in 5 normal subjects that these drugs did not affect the values of the nonvoluntary parameters which were examined in this study.

The probe was made with a Foley catheter which contained a side hole orifice of polyethylene tube measuring 2 mm in diameter. The balloon for stimulation in the rectum was placed at the tip of the probe and the side hole of the pressure receptor was located 4 em distally to the lower end of the balloon. The probe was filled with water before the examination, but not perfused with water during the examination. This ap- paratus was connected to a transducer (Toyo Baldwin Co., Ltd). A zero pressure, used through this study, was determined by recording atmospheric pressure at the external anal margin.

The anorectal pressure profile was first recorded in centimeters by withdrawing the probe which was introduced 8 cm above the mucocutaneous line in the rectum. To examine the anorectal reflex, the probe was set up for locating the pressure receptor in the high pressure zone after examination of the anorectal pressure profile. At this posi- tion, the presence or absence of an anorectal reflex was determined by distending the balloon in the rectum for 10 seconds with amounts of air varing from 10 to 30 ml.

RESULTS

Normal Subjects The 35 normal subjects, regardless of age, exhibited a characteristic pattern of

anorectal pressure profile at rest, as shown in Fig. 1 and all of the normal subjects had a high pressure zone in the anal canal region. Thus, as shown in Table 1, the average values of the anorectal resting pressure were found to be 9.1 -k0.6 cmH20 in the rectum, 21.8-b2.1 cmH20 in the upper anal canal (2 cm from the anal verge), and 23.4• cmH20 in the 4ower anal canal (1 em from the anal verge). When a length of this high pressure zone was defined as anal canal length it was 1.4-t-0.1 cm, and the mean ano-rectal pres- sure difference (maximum anal canal resting pressure minus the rectal resting pressure) was 15.4:~1.4 cmHeO.

The presence of an anorectal reflex was determined by three continuous pressure drops in the anal canal corresponding to rectal distension (Fig. 2). All of the normal

Jpn. J . Surg. 236 Iwai et al. Sept. 1979

Fig. 1. Anorectal pressure profile in the normal subjects. The record shows an intraluminal pressure as the probe is drawn from the rectum to the external anal margin.

Fig. 2. Presence of an anorectal reflex in normal subjects. Corresponding to rectal distension, rapid and marked pressure drop in the anal canal was found. This was defined as showing the presence of an anorectal reflex.

subjects had the presence of an anorectal reflex a nd the mean pressure drop of the reflex

was 12.7-b 1.3 c m H 2 0 .

Hirschsprung' s disease In the resting tracings, all of the 9 patients with Hirschsprung's disease showed the

same anorectal pressure profile as did the no rma l subjects, except for higher pressure in the anal canal (Fig. 3 & Tab le 1). The m e a n pressure was 31.6 -t-3.6 c m H 2 0 in the

Fig. 3. Anorectal pressure profile in Hirschsprung's disease. Anal resting pressure was significantly higher (P<0.05) than in that of the normal subjects.

Volume 9 Number 3 Anorectal Manometry in Hirschsprung' s Disease and Idiopathic Megacolon 237

~2

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0

~

<

"~ "-2.

-H -H -n

~e ~q. eq

eq -H -H -~

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Jpn. ,L Surg. 238 Iwai et al. Sept. 1979

uppe r ana l canal , 35.2:k4.3 c m H 2 0 in the lower ana l canal and the ano- rec ta l pressure difference was 27.3 ~_3.1 c m H 2 0 . These values were signif icantly h igher (p < 0.05) than those of the no rma l subjects.

As for the anorec ta l reflex, no r ap id pressure d rop in the anal cana l was found, cor responding to rectal distension (Fig. 4). Thus, the anorec ta l reflex was absent in all of the pat ients wi th Hi r schsp rung ' s disease.

Fig. 4. No rapid pressure drop in the anal canal was found, corresponding to rectal distension in the case of Hirschsprung's disease. This was defined as showing the absence of an anorectal reflex.

Fig. 5. Anorectal pressure profile in idiopathic megacolon: Lower anal resting pressure was significantly higher (P <0.05) than in that of the normal subjects.

Fig. 6. Presence of an anorectal reflex in idiopathic megacolon. Corresponding to rectal distension, rapid pressure drop in the anal canal was found. However, the pressure drop was less prominent than that of the normal subject without statistical significance.

Volume 9 Number 3 Anorectal Manometry in Hirschsprung's Disease and Idiopathic MegaeoIon 239

Idiopathic megacolon In the resting phase, all of the patients with idiopathic megacolon also exhibited the

same anorectal pressure profile with a marked high pressure zone in the anal canal as shown in the patients with Hirschsprung's disease (Fig. 5). The mean pressure was 23.6-1-2.2 cmH20 in the upper anal canal, 31.4• c m H 2 0 in the lower anal canal, and the anorectal pressure difference was 24.0• cmH20. These values, except for the upper anal pressures, were significantly higher (p<0.05) than those of the normal subj ects.

On rectal distension, all of the idiopathic megacolon patients had the presence of an anorectal reflex (Fig. 6). However, the mean pressure drop of the reflex was 9.24-1.5 cmH20, this value being lower than those of the normal subjects, but not statistically significant (0.05 < p < 01).

DiscussioN

Faced with the problem of megacolon in children, differentiation of Hirschsprung's disease from other forms of megacolon is important because the therapy of the former is surgical. In recent past, the diagnosis of Hirschsprung's disease was mainly made by radiologic examination and rectal biopsy. However, bar ium enema study may be dif- ficult to interpret, particularly in the cases of neonatal Hirschsprung's disease as well as in those of ultrashort aganglionosis. Also in rectal biopsy, which is the most certain method for the diagnosis of Hirschsprung's disease, histologic interpretation is sometimes difficult because of failure of obtaining an appropriate biopsy specimen, particularly in very short aganglionic segments; furthermore, rectal biopsy is not without risk since bleed- ing or perforation can occur.

In the past decade, the observation in normal subjects that the internal anal sphincter relaxes with a rise in rectal distension and that in Hirschsprung's disease this rectosphinc- teric reflex is absent has led to the proposal of the use of anorectal pressure measurement as a diagnostic test. At present, anorectal manometr ic study is a reliable and safe method for the diagnosis of Hirschsprung's disease, as has been shown by several authorsl,2,4, 6,%9 as well as our own study. In the present study using a simplified water-filled pressure probe system, the anorectal reflex was absent in all of nine patients with Hirschsprung's disease while in all of ten patients with idiopathic megacolon rectal distension produced a relaxation in the anal canal as in the normal subjects. Thus, anorectal manometr ic study has been found not only to provide a reliable and non-invasive technique for the diagnosis of Hirschsprung's disease, but also to permit differentiation of this disease from idiopathic megacolon on the response of the internal sphincter to rectal distension, as reported by Tobon et al, 9 and Aaronson and Nixon. 1 We consider, therefore, that this manometr ic examination justifies a place in the routine examination of I-Iirschsprung's disease along side of the bar ium enema and rectal biopsy, and is of particular value as a simple screening test in patients with a clinical suggestion of this disease.

In the present studies, special interest was focused on changes of the anorectal pres- sure at rest as well as at rectal distension. In the resting tracings, the patients with Hirsch- sprung's disease or idiopathic megacolon had significantly higher resting pressures in the anal canal than normal subjects. In general, it is the internal sphincter that contributes most of the resting pressure recorded from the anal canal by tubes or balloons. Ac- cordingly, this finding indicates that the tone of the internal sphincter at rest is very pronounced in these diseases.

Jpn. J . Surg. 240 Iwai et al. Sept. 1979

O n recta l distension, none of the pat ients wi th Hi rschsprung ' s disease had the reflex re laxa t ion of the in te rna l sphinc ter while a l l of the pat ients wi th id iopa th i c megaco lon exhib i ted the reflex. Howeve r , the pressure d rop (9.2=L1.5 c m H 2 0 ) in the anal cana l p roduced by rec ta l distension was less p rominen t c o m p a r e d with tha t of no rma l subjects (12.9d:1.3 cmHzO) . This f inding indicates tha t in the case of id iopa th ic megacolon, the in te rna l sphincter ac t iv i ty is only sl ightly suppressed by rec ta l distension.

I n the last 30 years there have been several reports showing an a b n o r m a l m o t o r pa t t e rn in the agangl ionic segment in Hi r schsprung ' s disease, and Swenson et al. s and H i a t t s h a d considered these mo to r abnormal i t i e s in the agangl ion ic segment to have a s ignif icant role in the obstruct ive symptoms in Hi r schsprung ' s disease. However , there h a d been li t t le in format ion r ega rd ing the funct ional status of the ana l sphincter in this disease un t i l m a n o m e t r i c studies p roved to be useful as d iagnos t ic stools. T o b o n et al. , 9 in 1968 based on anorec ta l m a n o m e t r i c studies, ra ised the possibilities tha t the consistent ly a b n o r m a l sphincter cont rac t ion i nduced by rec ta l dis tension also con t r ibu ted to the obs t ruc t ive symptoms in Hi rschsprung ' s disease. As descr ibed above, the m a n o m e t r i c studies of the pat ients wi th Hi rschsprung ' s disease or id iopa th ic megaco lon in the present series demon- s t ra ted s imilar results to those r epo r t ed by T o b o n et al. 9 I t is possible, therefore, t ha t the p ronounced in terna l sphinc ter cont rac t ion c o m b i n e d with a to ta l absence of reflex re laxa- t ion or an i nadequa t e response of this sphincter to rec ta l distension m a y be responsible for the obs t ruct ive symptoms in these diseases.

(Received for publication on September 6, 1978)

References

1. Aaronson, I. and Nixon, H. H.: A clinical evaluation of anorectal pressure studies in the diagnosis of Hirschsprung's disease, Gut 13: 138-146, 1972.

2. Boston, V. E. and Scott, J. E. S.: Anorectal manometry as diagnostic method in the neonatal period, J. Pediatr. Surg. 11: 9-16, 1976.

3. Hiatt, R. B. : Pathologic physiology of con- genital megac01on, Ann. Surg. 133: 313-320, 1951.

4. Holschneider, A. 1VL, Kellner, t3., Streibl, P. and Sippell, W. G.: The development of anorectal continence and its significance in the diagnosis of Hirsehsprung's disease, d. Pediatr. Surg. 11: 151-156, 1976.

5. Iwai, N., Ogita, S., Kida, M., Fujita, Y. and Majima, S.: A clinical and manometric correlation for assessment of postoperative

continence in imperforate anus, J. Pediatr. Surg. in press.

6. Lawson, J. O. and Nixon, H. H.: Anal canal pressures in the diagnosis of Hirschsprung's disease, J. Pediatr. Surg. 2: 54@552, 1967.

7. Schnaufer, L., Tatbert, J. L., Haller, J. A., Reid, N. C. R. W., Tobon, F., and Schuster, M. : Differential sphincteric studies in the diagnosis of ano-rectal disorders of child- hood, J. Pediatr. Surg. 2: 538-543, 1967.

8. Swenson, O., Rheinlander, H. F. and Dia- mond, I.: Hirschsprung's disease: new concept of etiology: operative results in thirty-four patients, New Eng. J. Med. 241 : 551-556, 1949.

9. Tobon, F., Reid, N. C. R. W., Talbert, J. L. and Schuster, M.: Nonsurgical test for the diagnosis of Hirschsprung's disease, New Eng. J. Med. 278: 188-194, 1968.