Voluntary anal continence after surgery for anorectal malformations

Voluntary Anal Continence After Surgery for Anorectal Malformations

By Naomi Iwai, Jun Yanagihara, Kazuaki Tokiwa, Eiichi Deguchi, and Toshio Takahashi

Kyoto, Japan

�9 Electromyography (EMG) and measurement of voluntary contraction pressure of the external sphincter muscle were performed in 28 patients, aged 5 to 14 years, to assess the function of the external sphincter after surgical correction of anorectal malformations. Ten normal children, aged 5 to 15 years, served as controls. External sphincter function in patients with high-type anomalies was disturbed in the areas of tonic activity, inflation reflex, and activity during further rectal filling. In patients with low-type or intermediate-type anomalies, function was preserved and was equal to that in normal controls. Phasic activity was observed in patients with all types of anomalies and in normal subjects. Among those with high-type anomalies, the three patients with Kelly's score of < 2 had voluntary contractions of 20 cmH20 or less. However, the mean voluntary contraction pressures were not significantly different among the three types of anomalies. Therefore, patients with high-type anomalies may acquire compensatory voluntary continence through bowel train-- ing. �9 1988 by Grune & Stratton. Inc.

INDEX WORDS: Anal continence; anorectal malformation; imperforate anus.

T HE IMPORTANCE of the puborectalis muscle in patients with high-type anorectal malformations

has been stressed by many investigators. On the other hand, it seems that the function of the external sphincter muscle has not been emphasized sufficiently. The external sphincter muscle provides fine control, especially at the time of a "sense of urgency."

The purpose of this study is to assess by electromyography (EMG) and anorectal manometry the function of the external sphincter in patients with anorectal malformations. The possibility of acquiring further voluntary anal continence is discussed.

MATERIALS AND METHODS

From 1960 to 1986, 140 patients with anorectal malformations were treated in the Division of Surgery, Children's Research Hospi- tal, Kyoto Prefectural University of Medicine. There were 66 patients (53 males and 13 females) with high-type, 23 patients (15 males and 8 females) with intermediate-type, and 51 patients (34 males and 17 females) with low-type anomalies. The usual operative procedure in this department has been a colostomy for the high and intermediate types in the neonatal period, followed by abdominoper- ineal rectolasty. At the time of the pull-through operation, the puborectalis sling is clearly observed with the aid of an electric stimulator, and this electric stimulator is also used to make a Y-shaped perineal skin incision within the external sphincter. Low- type anomalies have been treated by neonatal perineoplasty.

Of these 140 patients, 28 (13 with high-type anomalies, 6 with intermediate-type, and 9 with low-type) were tested with EMG of the external sphincter muscle and measurement of voluntary anal contraction pressure. The 13 patients with high-type anomalies were

aged 5 to 11 years, the six with intermediate-type, 5 to 9, and the nine with low type, 5 to 14. Ten normal controls, aged 5 to 15 years, were tested in the same way.

Electromyographic Assessment

Electromyography was recorded from the external anal sphincter by two surface electrodes placed just outside the anal orifice. The patient was grounded with a similar electrode. Electromyography was recorded on a Sanei (Tokyo) thermal pen recorder (Sanei-360, 8 channel polygraph), and the EMG electrodes were connected to a Sanei bioelectric amplifier. The time constant was 0.03 second. The patients were examined awake without sedation and in a supine position. An enema was given two hours before the examination.

The external sphincter electrogram at rest was first recorded. The electrical activity at rest was classified into three grades: ( + ) , an amplitude of 40 #V or higher; (_+), between 20 and 40 ~V; ( - ) , lower than 20 #V. When the rectum was transiently distended by a balloon containing 10 to 20 mL of air, contraction of the external sphincter was observed. This response was defined as the presence of an inflation reflex (Fig 1), as reported by Ihre. l The rectal balloon was further inflated to a maximum tolerable level, and the electrical activity was observed during rectal filling (Fig 2). In cooperative patients, the presence or absence of phasic activity during voluntary anal contraction was studied (Fig 3).

Manometric and Clinical Assessments

The manometric study was done only in cooperative patients. The probe was made with a Foley catheter, as we 2 previously reported. The probe was perfused at a constant speed of 10 mL/h . This apparatus was connected to a transducer (P231D: Gould Inc.), and the pressure was recorded on the Sanei thermal pen recorder.

Voluntary anal contraction pressures were measured twice at 2 cm and at 1 cm from the anal verge. The mean pressure was expressed as the voluntary contraction pressure.

Clinical assessment of functional results followed the Kelly score system 3 based on three criteria: (1) control of feces and bowel habits, (2) fecal staining, and (3) sling action of the puborectalis muscle.

RESULTS

N o r m a l Subjec ts

All ten normal subjects examined showed tonic activity at rest, and eight of the ten had a positive

From the Division of Surgery, Children's Research Hospital, Kyoto Prefectural University of Medicine, and the First Depart- ment of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.

Presented at the 20th Annual Meeting of the Pacific Association of Pediatric Surgeons, Seattle and Rosario, WA, April 26 to May 1, 1987.

Address reprint requests to Naomi lwai, MD, Division of Sur- gery, Children's Research Hospital, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602, Japan.

�9 1988 by Grune & Stratton, lnc. 0022-3468/88/2305-0002503.00/0

Journal of Pediatric Surgery, Vol 23, No 5 (May), 1988: pp 393-397 393

3 9 4 IWAI ET AL

- ~<L._ Recta d.stens o n _ <22 . . . . . . . . . - . . . . . . : . . . . . . . . . . . . : ; . . . . . . . . . .

. . . . ~ , _ . . . . . . . . . . / ' < . . ~ / ~ . . . . . . . - - ~ , . / . , : . . . . . . . . . . . . . . . . . . . . . . . . . . ~: . . . . . . . . : . . . . . . .

. . . . ,_ ~ . . . . . . . . , _ ~-_~/ 2 / - ~ , : _ / . \ . . . . . . /_.r . . . . . . . . ~ r ~

c m H = O . . . . . . .

- - ~ T : 4 . . . . - 2 - . - T ~ - 2 _ ~ . _ - - ~ - _ - T ~ = = - _ = - i . . . . . , - - - ~ ' 3 . 2 ~ - ~ - i _ . : L k : - ~ - , !

]

Fig 1. E l e c t r o m y o g r a p h y recording of t h e e x t e r n a l s p h i n c t e r d u r i n g r e c t a l d i s t e n s i o n in a p a t i e n t w i t h l o w - t y p e a n o m a l y . In response t o each rectal distension, relaxat ion of the anal canal pressure and contract ion of the externa l sphincter w e r e observed (arrows).

inflation reflex. Elec t r ica l act iv i ty dur ing fur ther rectal filling was increased in all ten.

Volun ta ry contrac t ion pressures 2 cm and 1 cm from the ana l verge were 52.0 _+ 7.0 c m H 2 0 and 63.6 _+ 9.1 c m H 2 0 , respectively.

Patients With Low-Type Anomalies

Tonic act ivi ty at rest was found in eight of the nine pat ients , and in one pa t ien t it was judged to be ( + ) (Tab le 1). An inflation reflex was observed in eight of the nine; the pa t ien t with a score of 4 did not have an inflat ion reflex. Elec t r ica l act ivi ty dur ing fur ther rectal filling was increased in all nine pat ients . Phas ic ac t iv i ty was present in all three pat ients who were cooperat ive in this examinat ion .

Volun ta ry cont rac t ion pressure could be measured in these three pat ients . The mean values of contrac t ion pressures 2 cm and 1 cm from the anal verge were 27.0 c m H 2 0 and 30.0 c m H 2 0 , respectively.

Patients With Intermediate-Type Anomalies

As shown in Tab le 2, tonic act ivi ty at rest was observed in all six pat ients . The inflation reflex was present in two of the six pat ients . E lec t r ica l act ivi ty dur ing fur ther rec ta l filling was increased in four pat ients with scores of more than 4. Al l six pat ients showed phasic act ivi ty dur ing voluntary contract ions .

The mean values of vo luntary cont rac t ion pressure 2 cm and 1 cm from the anal verge were 42.8 _+ 7.0 c m H 2 0 and 39.2 _+ 6.0 c m H 2 0 , respectively. The

Voluntary Contraction

2 1 cm

i, <

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} : ! ! : . ! External Sphificter { i !

--:-.:.--~.-i-{ i-~-+ :- ---: : _-~ ~[: 7-~ -~

~ : Respiration'-T -=-- - i l - I ] ~ - - - ~ U - - " [ : ~ I T : : [ : 1 3 ~ :_- . - - -_ - : .

"~i :: +7 ! . ? "7 t_--~ ~" + L [ : L --?i-- 7" t

-:i 3:.~--- i -~ f :~ -+- i i i ~ ] . . . . . : : . - - : :~ , : : . : : . . . . . . . . . . . .... : : . . .

Fig 2. Pressure m e a s u r e m e n t and EMG recording of the external sphincter during voluntary contract ion in a p a t i e n t w i t h l o w - t y p e anomaly, A r r o w s indicate p h a s i c activity. -:i-~ i [ : i :: I_ : i [ i : : - t . . . . . �9

VOLUNTARY ANAL CONTINENCE 395

9ressure in the balloon . . . . . . : , i = , i i i ! i :; : ; [ i ! .. ! "

~ > ~ t ~ - i , = ^ , ~ i ~ ~ I i i ~ . : : i : I ~--~ i , I i i ! - 7 I i i - ~ ~ I ~ i ' ~ }

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, - - . . q �9 . : : . - , ! , . ! . , . -

~-~ +-----r::-:~ ,..F~-,-v-I=:F:r-.:-:.~-,#--~_.-.q_:.~_:-[-:~:=--A_~-.i:.-I i.-=..!-..i I~, i l l !~i~[ -

_b_. .Fr:_. _ : _~_~ .~__-.|__ ~..: . . . . ~ _ : _..~__,__.,_:_~_ ~ _ ;.--.:, !-~---~_ -_+-<-:: L +-- .-r- :-- ~---- - ,-~-. .>::: - - -+-g

t : I " | I ; - : / : - - I - [ - I . - I . - : ' : - . 7 : . : " [ ' - ' - ' : T ; ~ , . I �9 ; ~ . ' W , " , , " ~ - q i . , i : i I . I

' ~ ! ~.xternal Shlnet~ " i " ~ :- ' " ! ~ : : : ' ' ! i " ' i _

Fig 3. Electromyography recording of the external sphincter during further rectal fil l ing in a patient w i th low-type anomaly. The fur ther rectal filling elicited renewed contraction of the external sphincter.

contraction pressure 1 cm from the anal verge was significantly (P < .05) lower than that of the normal controls.

P a t i e n t s W i t h H i g h - T y p e A n o m a l i e s

Tonic activity at rest was present in five of the 13 patients, and six patients had an electrical amplitude of 20 to 40 uV (_+) (Table 3). The remaining two patients had an electrical amplitude lower than 20/~V ( - ) . Two of the 13 patients showed the inflation reflex, and the remaining 11 had no inflation reflex. Electrical activity during further rectal filling was increased in three of the 12 patients, who had Kelly scores of more than 4 points. On the other hand, electrical activity was stationary in the remaining nine patients in spite of further rectal filling. Phasic activity was present in all of the eight patients who were cooperative in this examination.

The mean values of contraction pressure 2 cm and 1

cm from the anal verge were 33.5 _+ 6.7 cmH20 and 28.9 _+ 5.1 cmH20, respectively. The contraction pressure 1 cm from the anal verge was significantly (P < .01) lower than that of the normal controls, and there was no significant difference in voluntary contraction pressures between the high-type and intermediate-type anomaly groups.

DISCUSSION

Stephens and Smith 4 stressed the importance of the puborectalis muscle in providing fecal continence. However, they seemed to discount the importance of the external sphincter muscle.

In the present study, adequate electrical activity of the external sphincter at rest was observed in patients with low-type and intermediate-type anomalies. On the other hand, tonic activity was observed less often in patients with high-type anomalies. These results sug- gest that patients with high-type anomalies have a

Table 1. Electromyography Recordings and Contraction Pressures of the External Sphincter in Nine Patients With Low-Type Anomalies (Mean _+ SE)

EMG Recording Vo lun ta ry Contract ion Pressure (crnH20)

Ac t i v i t y Phasic Ac t i v i t y 2 cm f rom 1 cm f rom Age at Kel ly Tonic Inf lat ion During Further Dur ing Vo luntary the Ana l the Anal

Case Fo l low-up Score Ac t i v i t y Reflex Rectal Fil l ing Contract ion Verge Verge

1 5 5 + + Increased N E

2 5 6 + + Increased NE

3 14 4 + - Increased +

4 8 6 + + Increased +

5 5 5 _+ + Increased NE

6 9 -- + + Increased N E

(Trisomy 18)

7 5 6 + + Increased NE

8 6 6 + + Increased +

9 5 6 + + Increased N E

NE

NE

18 16

36 40

NE

NE

NE

28 34

NE

27.0 30.0

Abbreviation: NE, not examined.

396 IWAI ET AL

Table 2. Eleetromyography Recordings and Contraction Pressures of the External Sphincter in Six Patients With Intermediate-Type Anomalies (Mean _+ SE)

Case

EMG Recording Voluntary Contraction Pressure (emiliO)

Activity Phasic Activity 2 cm from 1 cm from Age at Kelly Tonic Inflation During Further During Voluntary the Anal the Anal

Follow-up Score Activity Reflex Rectal Filling Contraction Verge Verge

1 8 6 + -- Increased + 72 43

2 5 5 + + Increased + 58 66

3 8 4 + -- Increased + 30 42

4 9 6 + + Increased + 41 20

5 5 3 + -- Stationary + 22 26

6 6 4 + - Stationary + 34 38

42.8 +_ 7.0 39,2 _+ 6 .0

congenital function problem with the external sphincter muscle.

Gaston 5 reported that rectal distension normally elicited a brief contraction of the striated anal sphincter muscle; this response has been called the inflation reflex. Molander et al 6 showed that the presence of an inflation reflex correlated well with the development of voluntary anal continence. In the present study, all of the normal subjects and the patients with low-type anomalies did not necessarily have a positive inflation reflex. However, the inflation reflex was much more common in normal subjects and patients with low-type anomalies. This finding indicates that from the point of view of the inflation reflex, the function of the external sphincter is more fre- quently disturbed in patients with high-type anomalies. In addition, it is noteworthy that patients with an inflation reflex had good Kelly scores regardless of the type of anorectal malformation.

Electrical activity of the external sphincter was recorded when the balloon in the rectum was inflated further. All of the normal subjects showed increased

activity during further rectal filling; this result is in agreement with Ihre's report. In most of the patients with high-type anomalies, electrical activity of the external sphincter was stationary in spite of further rectal filling. Therefore, electrical activity during further rectal filling is an index of external sphincter function in patients with high-type anomaly, as is tonic activity or the inflation reflex.

Ihre showed that in normal subjects, electrical activity of the external sphincter reached a higher amplitude, corresponding to voluntary contraction of the anal canal, and this response has been called phasic activity. In the present study, phasic activity was observed in patients with high-type anomalies as well as in patients with other types of anomalies and in normal subjects. This result indicates that although patients with high-type anomalies may have congeni- tally rudimentary external sphincter muscles, they still may be able to improve external sphincter function.

Arhan et al 7 previously reported that pressure in the upper anal canal during contraction is significantly lower in incontinent subjects, although this deficiency

Table 3. Electromyography Recordings and Contraction Pressures of the External Sphincter in 13 Patients With High-Type Anomalies (Mean • SE)

EMG Recording Voluntary Contraction Pressure (cmH20)

Activity Phasic Activity 2 cm from 1 cm from Age at Kelly Tonic Inflation During Further During Voluntary the Anal the Anal

C a s e Follow-up Score Activity Reflex Rectal Filling Contraction Verge Verge

1 5 3 - -- NE NE

2 5 4 -+ - Stationary N E

3 6 3 • - Stationary NE

4 6 4 -+ + Stationary N E

5 7 2 +- -- Stationary + 18

6 11 1 + - Stationary + 20

7 5 1 -+ -- Stationary + 10

8 6 4 -+ - Increased + 36

9 5 4 - -- Stationary N E

10 8 4 + + Increased + 74

11 10 6 + -- Increased + 46

12 7 4 + -- Stationary + 38

13 11 4 + - Stationary + 24

33.5 _+ 6.7

NE

NE

NE

NE

NE

13

20

10

36

50

50

22

28

28.9 _+ 5.7

Abbreviation: NE, not examined.

VOLUNTARY ANAL CONTINENCE 397

is less f requent than the rec toana l inhibi tory reflex or a lower anal pressure at rest. In the present s tudy, the three pat ients with Kel ly ' s score of <2 had voluntary contract ion pressure of 20 c m H 2 0 or less. However , there was no significant difference in vo luntary con- t rac t ion pressures among the three types of anomaly .

The results of phas ic act ivi ty and vo lun ta ry anal contrac t ion pressure test ing indicate tha t pat ients with h igh- type anomal ies m a y achieve compensa to ry volun- t a ry cont inence of defecat ion if the ex te rna l sphincter muscle is developed by vo lun ta ry bowel t ra ining.

REFERENCES

1. lhre T: Studies on anal function in continent and incontinent patients. Scand J Gastroenterol Suppl 25, 1974

2. lwai N, Ogita S, Kida M, et al: A clinical and manometric correlation for assessment of postoperative continence in imperforate anus. J Pediatr Surg 14:538-543, 1979

3. Kelly JH: Cineradiography in anorectal malformations. J Pediatr Surg 4:538-546, 1969

4. Stephens FD, Smith ED: Anorectal Malformations in Chil- dren. Chicago, Year Book Medical, 1971

5. Gaston EA: The physiology of fecal continence. Surg Gynecol Obstet 87:280-290, 1948

6. Molander ML, Frenckner B: Electrical activity of the external anal sphincter at different ages in childhood. Gut 24:218-221, 1983

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

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Voluntary anal continence after surgery for anorectal malformations