INDEPENDENT PAPERS

A Clinical and Manometric Correlation for Assessment of Postoperat ive Continence in Imperforate Anus

By Naomi Iwai, Shuhei Ogita, Makoto Kida, Yoshihiro Fujita, and Susumu Majima

Kyoto, Japan

�9 Functional results af ter surgical correct ion of anorectal mal format ions were assessed on a clinical basis fol lowing Kelly score and by manometr ic study. Forty-six pat ients, aged 2 - 1 7 , w e r e personally inter- v iewed and 2 5 of these 46 had manometr ic studies to evaluate postoperat ive continence. The mano- metr ic study was also per formed on 35 normal children as a control group. Cont inent pat ients char- acter ist ical ly had marked high pressure zones as did the normal subjects. On the other hand, in the pat ients w i th fair or poor results, the anorectal pressure profile had no marked high pressure zone in the anal canal. The presence of normal anal pressure at rest as well as adequate ano-rectal pressure di f ference was found to corre late wel l wi th cont inence. In pat ients w i th perineoplasty, the ano- rectal ref lex corre lated wel l wi th continence but not in pat ients t rea ted by abdominoperineal rectoplasty.

INDEX W O R D S : Anorecta l malformations; imperfo- rate anus; anorectal manometry .

F U N C T I O N I N G RESULTS after surgical correction of anorectal malformations have

been assessed mainly on a clinical basis. Yama- rnoto et al. t in our department of surgery previously reported the result of surgical treal- ment of imperforate anus based on clinical assessment following the Kelly 2 score. More recently, objective assessment of continence by manometric and radiologic studies 3-6 have been added for the complete evaluation of these patients. The purpose of this paper is to correlate the clinical and manometric assessment of conti- nence in patients operated upon for imperforate a m l s .

MATERIALS AND METHODS

Of 64 patients with reconstructive surgery for imperforate anus between 1960 and 1977 in the First Department of

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

Address reprint requests to Naomi IwaL M.D.. The First Department of Surgery. Kyoto Prefectural University of Medicine. Kajiicho. Hirokoji Kawaramachi, Kamigyo-ku, Kyoto, Japan

�9 1979 by Grune & Stratton, Inc. 0022-3468/79/1405~009501.00/0

Surgery, Kyoto Prefectural University of Medicine, 3 died of postoperative complications in the neonatal period. Clinical details of the remaining 61 patients were reviewed and followed. Forty-six, aged 2- [7 , were personally interviewed and 25 of these 46 had manometric studies to evaluate postoperative continence. The latter was also performed on 35 normal children, aged 2-6 (with a mean age of 4 yr and 3 me), as a control group.

The details of the operative procedures and postoperative observation period in the 46 patients studied are outlined in Table 1. Their follow-up periods after surgery were at least one to 16 yr, the mean postoperative duration being 4 yr and 9 me.

Manometric Assessment

The manometric study was performed without special bowel preparation. This study was done principally without anesthesia, except in restless children who required mild sedation at the time of examination (Ketamine chloride 5 mg /kg by intramuscular injection or thiopental sodium 30 mg/kg per rectum). In five normal subjects neither of these drugs was found to affect the value of the nonvoluntary parameters that was examined in this study.

The probe was made with a Foley catheter that contained a side hole recording orifice of polyethylene tubing measur- ing 2 ram in diameter. The balIoon for stimalation in the rectum was placed at the tip of the probe and the side hole of the pressure receptor was located 4 cm distal to the lower end of the balloon. The probe was filled with water before the examination, but was not perfused during the examination. This apparatus was connected to a transducer (Toyo Baldwin Co., Ltd.) and the pressure was recorded on a polygraph (Sanei k-012). A zero pressure, used throughout this study, was determined by recording atmospheric pressure at the anal margin.

The anorectal pressure profile was first recorded in centi- meters by withdrawing the probe that was introduced 8 cm above the mucocutaneous line in the rectum. To examine lhe 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 position, the presence or absence of an anorectal reflex was determined by distending the balloon in the rectum for 10 sec with amounts of air varying from 10 to 30 ml.

Clinical Assessment

Clinical assessment of functional results followed the Kelly score system that is based on 3 criteria: (1) control of feces and bowel habits, (2) fecal staining, and (3) sling action of the pubcrectaIis rn~,cle. The results were ciassified as good (Kelly 5-6), fair (Kelly 3-4), and poor (Kelly 0-2).

538 Journal of Pediatric Surgery, Vol. 14, No. 5 (October), 1979

POSTOPERATIVE CONTINENCE IN IMPERFORATE ANUS 539

Table 1. Number of Cases in Which We Performed

Clinical Assessment With Their Mean

Postoperative Durations

Mean Follow-Up

Procedure Number Periods

Staged abdominoperineal

rectoplasty

High type 22 53/4 yr

Intermediate type 6 2 ~ 1/12 yr

Perineoplasty

Intermediate type 5 411/12 yr

Low type 13 5%2 yr

Normal subjects 35 41/4 yr

RESULTS

Normal Subjects

The 35 normal subjects examined exhibited a characteristic pattern of anorectal pressure profile (Fig. 1). As the probe was drawn into the anal canal, a sharp rise in pressure occurred and a sharp decline of pressure was observed at the external anal margin. All of the normal subjects had a markedly high pressure zone in the anal canal.

The average values of the anorectal resting pressure were 9.1 _+ 0.6 cmHzO in the rectum, 21.8 _+ 2.1 cmH20 in the upper anal canal (2 cm from the anal verge), and 23.4 + 1.9 cmH20 in the lower anal canal (1 cm from the anal verge). Thus the anorectal pressure difference (maxi- mum anal canal resting pressure minus the rectal resting pressure) was 15.4 _+ 1.4 cmH20, and when a length of this high pressure zone was defined as anal canal length it was 1.4 + 0.1 cm.

The presence of an anorectal reflex was deter- mined by three continuous pressure drops in the anal canal corresponding to rectal distention

(Fig. 2). All of the normal subjects exhibited the presence of an anorectal reflex.

Patients With Surgical Correction

Clinical assessment and manometric values of anorectal structures in the patients with imper- forate anus after reconstructive surgery are summarized in Tables 2-4.

Clinical assessment following Kelly Score (Table 2). Of the 13 patients with the low type, 12 (92%) had good control, and in 11 patients with the intermediate type, 6 (55%) achieved good control. In 22 patients with the high type, however, only 5 (23%) had good control, and in the remainder it was fair or poor.

Anorectal pressure profile (Table 3). A total of 14 patients with good results (6 of staged abdominoperineal rectoplasty and 8 of perineo- plasty) exhibited the same anorectal pressure profile with a high pressure zone in the anal canal as did the normal subjects (Fig, 3). The values of rectal, upper anal, and lower anal resting pressures were not significantly different from those of normal subjects. Anorectal pres- sure differences in the staged abdominorecto- plasty or perineoplasty were 16.5 _+ 3.2 cmH20 or 14.6 _+ 1.5 cmH20, and their anal canal length 1.5 _+ 0.2 cm or 1.2 +_ 0,2 cm, respec- tively. These values were also not significantly different from those of normal subjects.

Ten patients with fair results (8 of staged abdominoperineal rectoplasty and 2 of perineo- plasty) showed a somewhat different pattern of anorectal pressure profile with a less prominent high pressure zone in the anal canal (Fig. 4). Both of the upper and lower anal pressures were significantly lower (p < 0.05) as compared with

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Fig. 1. Anorectal pressure profile in normal subjects. The record shows an intraluminal pressure as the probe is drawn from the rectum to the external anal margin. Distances are in centimeters from the mucocutaneous line. Normal subjects had a marked high pressure zone in the anal canal. A sharp rise in pressure occurred as the probe was drawn into the anal canal and a sharp decline of pressure was found as the external anal margin was approached,

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540 IWAI ET AL.

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Fig. 2. Presence of an anorectal reflex in normal subjects. Rectal distension causes a pressure drop in the anal canal. Three of these continuous pressure drops in the anal canal corresponding to rectal distension are defined as showing the presence of an anorectal reflex.

Table 2. Functional Results and Type of Anorectal Malformations

Functional Results No. of

Procedure Patient Good Fair Poor

High Type Staged abdominoperineal 22 5 (23%) 12 (54%) 5 (23%) rectoplasty

Intermediate type Staged abdominoparineal i } i } i } ~ } rectoplasty 11 6 (55%) 5 (45%) 0 Perineoplasty

Low type Perineoplasty 13 12 (92%) 1 (8%) 0

p < .O01.

Table 3. A Clinical Assessment and Manometric Study of Anorectal Structures in Imperforate Anus After Reconstructive Surgery (X + SE)

Rectal Upper Anal Lower Anal Anal Canal Functional No. of Pressure Pressure Pressure Length ARPD

Results Procedure Patient (cmHzO) (cmHzO) (cmH20) (cm) (cmH20)

Good Staged abdominoperineal

rectoplasty 6 10.8 _+ 1.6 24.5 _+ 4.4* 23.2 • 5.3* 1.5 +_ 0.2 16,5 + 3.2 t

Perineol31asty 8 7.5 • 0 .8 19.4 • 1.8" 2 0 5 +- 2 3 * 1.2 • 0.2 14.6 _+ 1,5 t

Fair Staged abdominoperineal

rectoplasry 8 7.3 _+ 1.2 13.5 + 1,9 ~ 10.3 +- 1,9" 1.7 • 0 .5 8.O -+ 1.3 t

Perineoplasty 2 9.O 18.5 18.O 1 ,O 9.5

Poor Staged abdominoperineal "

rectoplasry 1 1 O.O 13.O 12.5 - - 3.O

Normalsubjecrs 35 9.1 • 0 ,6 21.8 • Z . I * 23.4 • 1.9" 1.4 • O.1 15.4 --+ 1.4~

ARPD = Anorectal pressure difference. *Difference between good, normal & fair was p < .05. tDifference between good, normal & fair was p < .05.

Table 4. Relationships Between Functional Results and the Anorectal Reflex

Anorectal Reflex Functional No. of Results Procedure Patient Present Absent

Good S* e0a nea, it it it rectoplasty 14 9 (64%) 5 (36%) Perineoplasty

rectoplasty 10 2 (20%) 8 (80%1 Perineoplasty

Poor Staged abdominoperineal rectoplasty 1 0 1

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POSTOPERATIVE CONTINENCE IN IMPERFORATE ANUS

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those of the good cases as well as in the normal subjects, Accordingly, anorectal pressure differ- ences in the fair group were significantly lower (p < 0.05) than those of normal subjects. However, anal canal length was identical with that of normal subjects.

In one patient who had undergone staged abdominoperineal rectoplasty, the anorectal pressure profile showed a slight radial change (Fig. 5) and had not such a high pressure zone as was found in the anal canal of normal subjects. The anorectal pressure difference was as low as 3 cmH20, and it was difficult to define the anal canal length in this case.

Anorectal reflex (Table 4). In 14 patients with good control, 9 (64%) showed an anorectal reflex (Fig. 6), while it was found in 2 (20%) out of 10 patients with fair results (Fig. 7). It is notable to point out that of the 6 patients with good results after staged abdominoperineal rectoplasty, only 2 had an anorectal reflex and in the remaining 4 patients this reflex was not observed.

DISCUSSION

The clinical assessment of the patients with imperforate anus in this series demonstrated results that agree with most of the previous

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542 IWAI ET AL.

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reports. 4-6 The incidence of patients with good results who had adequate continence was extremely high (92%) in the low type lesions compared to 23% in the high type anomalies. From these data, it is obvious that patients with low type lesions treated by perineoplasty are more likely to be continent while patients with high type lesions operated on by abdominoperi- neal rectoplasty have more problems with conti- nence.

Continence after reconstructive surgery for imperforate anus is related to multiple factors. Manometric investigations in the present study have shown that good clinical results after peri- neoplasty or abdominoperineal rectoplasty were associated with a normal function of the rectum. This was demonstrated not only by the presence of a normal anorectal pressure profile, but also by the presence of an anorectal reflex.

The anoreclal pressure profile, observed in all of the patients with adequate continence, char- acteristically had a marked high pressure zone as did the normal subjects, and it permitted us to determine the length and the pressure height of a new anal canal, as well as the anorectal pressure difference. Thus, it was demonstrated that these parameters of the continent patients were not significantly different from those of normal subjects. On the other hand, in the patients with fair (inadequate continence) or poor results (incontinence), the anorectal pressure profile had no marked high pressure zone in the anal canal, and both the anal resting pressures and

the anorectal pressure differences were signifi- cantly lower than in those of the continent patients, as well as in those of normal subjects. Thus, the presence of normal anal pressure at rest as well as adequate anorectal pressure difference was found to correlate well with conti- nence subsequent to surgery for imperforate anus.

The anorectal reflex assessed in this study has been the response in the anal canal to distension of a balloon in the rectum, This reflex was observed in 7 to 8 patients who had adequate continence following perineoplasty while it was demonstrated in only 2 out of 6 patients who had continence after staged abdominoperineal recto- plasty, In addition, it was noted that a reflex was present in two patients who had some degree of incontinence after surgery for a low or an inter- mediate type of deformity. These results indicate that in patients with perineoplasty the reflex is correlated well with continence but not in patients treated by abdominoperineal recto- plasty. Accordingly, it seems that the reflex is not essential to achieve continence at least in patients treated by the latter procedure.

Some investigators (Schali ct al. 4, Taylor et al), and Arhan et al. 6) have previously reported that on manometrical grounds, fecal continence is related to multiple factors such as the presence of an anorectal reflex, and adequate length of anal resistance represented by anal resting pres- sure.

In the present study, it is also true that the

Fig. 6. Anorectal reflex in a good postoperative case_

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POSTOPERATIVE CONTINENCE IN IMPERFORATE ANUS 543

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presence of a normal anal resting pressure is essential to achieve continence. However, the anorectal reflex in the high type does not neces- sarily correlate well with continence. This might be explained as follows: after a staged abdomino- perineal rectoplasty for a high type lesion, only a mechanical resistance remains without sensitive receptors in the mucosa that is concerned with

initiating the anorectal reflex. Thus, normal anal resting pressure (marked high pressure zone), an adequate canal length, and an adequate ano- rectal pressure difference in a high type lesion are apparently more important factors relating to continence after reconstructive surgery for imperforate anus.

R E F E R E N C E S

1. Yamamoto M, Kojima O, Kida M, et al: Functional prognosis after surgical correction for imperforate anus. Shujutsu (Operation) 27:59-65, 1973

2, Kelly JH: Cineradiography in anorectal malforma- tions. J Pediatr Surg 4:538-546, 1969

3. Cywes S, Cremin B J, Louw JH: Assessment of conti- nence after treatment for anorectal agenesis: A clinical and radiologic correlation. J Pediatr Surg 6:132-137, 1972

4. Schari AF, Kiesewetter WB: Imperforate anus: Anor- ectosigmoid pressure studies as a quantitative evaluation of postoperative continence. J Pediatr Surg 4:694-704, 1969

5. Taylor 1, Duthie HL, Zachary RB: Anal continence following surgery for imperforate anus. J Pediatr Surg 8:497-503, 1973

6. Arhan P, Faverdin C, Devroede Gr, et al: Manometric assessment of continence after surgery for imperforate anus. J Pediatr Surg 11:157-166, 1976