A n i s m u s : Fact or Fiction? W. R. Schouten, M.D.,* J. W. Briel, M.D.,* J. J. A. Auwerda, M.D.,* J. H. van Dam, M.D.,* M. J. Gosselink, M.D.,* A. Z. Ginai, M.D.,t W. C. J. Hop, M.Sc.~: From the Departments of*Surgery, tRadiology, and ~Epidemiology and Biostatistics, University Hospital Dijkzigt, Rotterdam, The Netherlands PURPOSE: Although anlsmus has been considered to be the principal cause of anorectal outlet obstruction, it is doubtful whether contraction of the puborectalis muscle during straining is paradoxical. The present study was conducted to answer this question. METHODS: During the first part of the study, we retrospectively reviewed 121 patients with constipation and/or obstructed defecation (male:female, 10/111; median age, 51 years). All of these patients underwent electromyography (EMG) of tile pelvic floor and the balloon expulsion test (BET) in the left lateral position. Evacuation proctography was performed in all of these patients in the sitting position. Both the posterior anorectal angle and the central anorectal angle were measured. EMG and BET were also performed in ten controls (male:female, 4/6; median age, 47). In 147 patients with fecal incontinence (male:female, 24/123; median age, 58) only EMG activity was recorded. Criteria for anismus during straining were increase or insufficient (<20 percent) decrease of EMG activity, failure to expel an air-filled balloon on BET, and decrease or insufficient ( < 5 percent) increase of anorectal angle on evacuation proctography. Between June 1994 and March 1995, we conducted a second prospective study in a consecutive series of 49 patients with constipation and/or obstructed defecation and 28 patients with fecal incontinence. Both groups were compared with 19 control subjects. In this study, all three tests were performed. EMG and BET were performed both in the left lateral position and in the sitting position. RESULTS: The retrospective study was undertaken by comparing the constipated patients with the incontinent patients and the controls, and the anismus detected by EMG was found in, respectively, 60, 46, and 60 percent. Failure to expel the air-filled balloon was observed in 80 constipated patients (66 percent) and in 9 control subjects (90 percent). Based on posterior anorectal angle and central anorectal angle measurements, anismus was diagnosed in, respectively, 21 and 35 percent of constipated patients. In the prospective study, none of the tests showed significant differences regarding the prevalence of anismus between the two subgroups of patients and the control subjects. The prevalence of anismus only differed between constipated and incontinent patients when the diagnosis was based on BET in the sitting position (67 vs. 32 percent; P < 0.005). Our study shows that contraction of the puborectalis muscle during straining is not exclusively found in patients with constipation and/or obstructed defecation. The three tests most commonly used for the diagnosis of anismus showed an extremely poor agreement. CONCLUSION: Based on these findings, w e doubt the clinical significance of anismus. [Key words: Anismus; Electromyography; Balloon expulsion test; Evacuation proctography]

Read at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995. No reprints are available. 1033

Schouten WR, Briel JW, Auwerda JJA, van Dam JH, Gosselink MJ, Ginai AZ, Hop WCJ. Anismus: fact or fiction? Dis Colon Rectum 1997;40:1033-1041. o n s t i p a t i o n a n d d i s o r d e r e d d e f e c a t i o n are the m o s t c o m m o n digestive c o m p l a i n t s . M a n y asp e c t s o f t h e s e c o n d i t i o n s c a n b e a t t r i b u t e d to d i e t a r y fiber d e f i c i e n c y a n d p s y c h o g e n i c influences. H o w ever, t h e r e is g r o w i n g e v i d e n c e that a d d i t i o n a l factors are i n v o l v e d in b o t h conditions. Usually c o n s t i p a t i o n is d e f i n e d as i n f r e q u e n t d e f e c a t i o n , w i t h t w o or f e w e r

C

b o w e l m o v e m e n t s w e e k l y . T h e history o f the p a t i e n t is a useful clinical g u i d e to d e l i n e a t e p a t i e n t s w i t h c o n s t i p a t i o n c a u s e d b y c o l o n i c inertia f r o m t h o s e w i t h o b s t r u c t e d d e f e c a t i o n . Most patients w i t h slow-transit c o n s t i p a t i o n h a v e n o u r g e to d e f e c a t e d u r i n g t h e d a y s or weeks before having a bowel movement, whereas those with obstructed defecation have a regular and s o m e t i m e s daily u r g e to d e f e c a t e . M e a s u r e m e n t o f c o l o n i c transit time is a n o t h e r k e y to s u b d i v i d e p a tients into o n e o f t h e t w o g r o u p s . A n i s m u s is d e f i n e d as i n a p p r o p r i a t e c o n t r a c t i o n o f the p e l v i c floor d u r i n g a t t e m p t e d e v a c u a t i o n . This p h e n o m e n o n has b e e n cited as t h e p r i n c i p a l c a u s e o f o b s t r u c t e d d e f e c a t i o n . Although physical examination may be suggestive of s u c h a " p a r a d o x i c a l " contraction, m o s t a u t h o r s a d v o cate a n o r e c t a l p h y s i o l o g i c e v a l u a t i o n to assess the r e a c t i o n of the p e l v i c floor d u r i n g straining efforts. E l e c t r o m y o g r a p h y (EMG), b a l l o o n e x p u l s i o n test (BET), a n d e v a c u a t i o n p r o c t o g r a p h y (EP) are m o s t c o m m o n l y u s e d for the d i a g n o s i s o f anismus. Unfortunately, t h e s e tests o v e r e s t i m a t e t h e true p r e v a l e n c e of anismus, probably because they poorly represent the natural p h y s i o l o g y o f d e f e c a t i o n . ~ T h e current d i a g n o s t i c m e t h o d s m a y b e quite e m b a r r a s s i n g for the patient. F u r t h e r m o r e , d u r i n g testing, the p a t i e n t s m a y n o t n e e d to defecate. Straining w i t h o u t a natural d e sire to d e f e c a t e is rather u n p h y s i o l o g i c a n d m i g h t p r o v i d e findings u n r e l a t e d to the u n d e r l y i n g disorder. If p a r a d o x i c a l c o n t r a c t i o n o f the p e l v i c floor r e p r e sents a m a j o r c o n t r i b u t i n g factor to the p r o b l e m o f o b s t r u c t e d d e f e c a t i o n , this " s y n d r o m e " s h o u l d b e a specific finding in patients w i t h e v a c u a t i o n difficul-

1034

SCHOUTEN ETAL

ties. However, signs of anismus have b e e n noted in controls, 2 patients with anorectal pain, 3 and even in subjects with fecal incontinence. 4 The clinical significance of anismus has also b e e n questioned, because current diagnostic tests are poorly correlated. It has b e e n reported, for example, that patients with radiologic signs of anismus are able to evacuate their rectum completely. 1 In another study, no correlation was found b e t w e e n electromyographic evidence of anismus and the ability of the patient to e m p t y the rectum. 5 Dahl and associates 6 reported that 13 of 14 patients with electromyographic signs of anismus were able to expel an inflated balloon. Based on this finding, they concluded that the BET is not a useful marker of paradoxical contraction. Most reports that have b e e n published so far are retrospective reviews of small and selected series of patients. Moreover, most authors used only one or occasionally two tests to verify the diagnosis of anismus. There are only a few studies evaluating the problem of obstructed defecation using three or more tests. Regarding the EMG criteria, we c o m p a r e d the constipated patients with incontinent subjects and controls to examine whether this p h e n o m e n o n is specific for constipation and/or obstructed defecation. Because all three tests (EMG, BET, EP) were not used in our retrospective study, w e conducted a prospective study in a consecutive series of patients, in w h o m all three tests were performed. PATIENTS AND

METHODS

During the first retrospective study, which was conducted in the time period b e t w e e n 1989 and 1994, 121 patients with constipation and/or obstructed defecation underwent EMG of the pelvic floor and BET in the left lateral position. Evacuation proctography was performed in all of these patients in the sitting posi-

Dis Colon Rectum, September 1997

tion. EMG and BET were also performed in ten control patients. EMG activity of the puborectalis muscle during straining was also recorded in 147 patients with fecal incontinence. During the second prospective study, which was conducted in the time period b e t w e e n June 1994 and March 1995, all three tests were performed in a consecutive series of patients with either constipation and/or obstructed defecation (n = 49) or fecal incontinence (n = 28). The results obtained in these patients were c o m p a r e d with those obtained in a n e w control group (n = 19). EMG and BET were performed both in the left lateral position and in the sitting position. The demographics of all patients and controls are listed in Table 1. The control subjects w h o entered the first part of the study were recruited from those awaiting surgery for familial polyposis coli (n = 6). The other four subjects were attending surgery for various colonic abnormalities, such as adenomatous polyps. None of these ten subjects complained of constipation, obstructed defecation, or fecal incontinence. The controls w h o entered the second part of the study were recruited in three groups. Nine subjects presented with chronic idiopathic anorectal pain. Despite this so-called levator syndrome, all of these nine patients had a completely normal defecation pattern. Eight patients were attending a barium e n e m a for reasons other than constipation, obstructed defecation, or fecal incontinence. Two subjects were healthy volunteers. Electromyography EMG recordings were obtained without bowel preparation. During the first part of the study, EMG was only performed with the subject in the left lateral position and with the knees and hips flexed at 90 ~ A

Table 1. Demographics of Controls and Two Subgroups of Patients No. of Patients

Gender (M/F)

Median Age (yr)

Range (yr)

10 121 147

4/6 10/111 24/123

47 51 58

19-87 24-85 26-76

19 49 28 375

10/9 4/45 3/25 55/320

48 47 52 53

19-76 24-73 19-75 19- 87

Retrospective study Controls

Constipation Incontinence

Prospective study Controls

Constipation Incontinence

Total Retrospective study = time period between 1989 and 1994; prospective study = time period between 1994 and 1995.

Vol. 40, No. 9

ANISMUS: FACT OR FICTION?

conventional concentric bipolar needle electrode was inserted without anesthetic into the puborectalis muscle. Standard EMG apparatus was used to amplify and display the potentials. Before and during m a x i m u m straining efforts, recordings were m a d e from the puborectalis muscle. During the second part of the study, EMG was also performed while the patient was seated on a commode. Electromyographic evidence of anismus was based on the following criteria: increased activity, no change, or insufficient inhibition ( < 2 0 percent) during a m a x i m u m straining effort. Evacuation

Proctography

In all patients, an evacuatory suppository was administrated several hours before the procedure. Evacuation proctography was performed using the m e t h o d as earlier d e s c r i b e d ] The anorectal angle was measured in two ways. The posterior anorectal angle (PAP, A) was defined as the angle b e t w e e n the central axis of the anal canal and a designated line along the posterior wall of the distal part of the rectum. The central anorectal angle (CARA) was measured as the angle b e t w e e n the central axis of the anal canal and the central axis of the distal part of the rectum. Both angles were measured at rest and at the end of a m a x i m u m straining effort. Radiologic evidence of anismus was defined on the following criteria: decrease or insufficient increase ( < 5 percent) of PARA or CAR& despite an adequate straining effort, represented b y sufficient perineal descent. Balloon Expulsion

Test

Initially, the BET was only performed with the patient in the left lateral position. During the second part

1035

of the study, the BET was also performed while the patient was seated on a c o m m o d e . The balloon was made from a finger condom, which was tied around a rigid polyvinyl catheter with an external diameter of 2 mm. With the patient in the left lateral position, the lubricated balloon was inserted into the rectum. First, the balloon was inflated with air until the patient experienced an urge to defecate. Then, the patient attempted to pass the balloon within 20 seconds. The ability to expel the inflated balloon was also studied while the patient was seated on a c o m m o d e . Failure to expel the air-filled balloon was considered to be a criterion for anismus.

Statistical Analysis Percentages were c o m p a r e d b e t w e e n groups using the chi-squared test and within groups using the McNemar test. P = 0.05 (two-sided) was considered the limit of significance. To assess the agreement b e t w e e n various diagnostic tests, k a p p a values were calculated ( k a p p a values of 0.4-0.6 are generally considered to represent moderate agreement and a b o v e 0.6 to be g o o d agreement). RESULTS Retrospective

Study

Comparing constipated patients with incontinent subjects and controls, anismus detected by EMG was found in, respectively, 60, 46, and 60 percent (Table 2). During this part of the study, the BET was only performed in the left lateral position both in patients with constipation and/or obstructed defecation and in control subjects. Failure to expel the air-filled balloon

Table 2. Prevalence of Anismus (%) in Controls and Two Subgroups of Patients

EMG Lying Retrospective study Controls Constipation Incontinence Prospective study Controls Constipation Incontinence

BET Sitting

60 60 46 58 47 61

68 67 79

Lying

EP Sitting

Posterior Angle

Central Angle

9 0

- -

- -

- -

66

--

21

35

79 86 68

42 67 32*

5 10 21

16 22 36

EMG = electromyography; BET = balloon expulsion test; EP = evacuation proctography; Lying = left lateral position; Sitting = sitting position; Retrospective study = time period between 1989 and 1994; Prospective study = time period between 1994 and 1995. * Incontinent vs. constipated patients; P < 0.005.

1036

SCHOUTEN E T A L

was observed in 80 constipated patients (66 percent) and in 9 control subjects (90 percent). Based on PAPA and CARA measurements, EP showed anismus in, respectively, 21 and 35 percent of the constipated patients (Table 2).

Prospective Study During this part of the study, all patients and control subjects underwent EMG, BET, and EP. Both EMG and BET were performed in the left lateral position and in the sitting position. The separate prevalences of anismus based on the three tests are listed in Table 2. None of the tests showed significant differences regarding the prevalence of anismus between the two subgroups of patients and the control subjects. The prevalence of anismus only differed between constipated and incontinent patients w h e n the diagnosis was based on BET in the sitting position (67 vs. 32 percent; P < 0.005). The prevalence of anismus, detected by EMG in the left lateral position and the sitting position, among all patients and subjects was, respectively, 53 and 71 percent. Although this difference is significant (P < 0.001), the agreement is moderate according to kappa values. Based on these data, it is not clear which of the two measurements is the optimum one. Thirty-four percent of the patients w h o were unable to expel the air-filled balloon in the left lateral position, were able to do so in the sitting position. This finding illustrates the moderate agreement (Table 3) between BET in the sitting position and the left lateral position. Radiologic evidence of anismus d e p e n d e d on the way the anorectal angle (ARA) was measured. Based on PARA and CARA measurements, the prevalence of anismus among all patients and subjects was, respectively, 13 and 25 percent. Although this difference is significant (P < 0.005), the agreement between PARA and CARA measurements is moderate according to kappa values. Based on these data, it is not clear Table 3. Kappa Values of Different Tests

EMG sitting BET sitting EP central angle

EMG Lying

BET Lying

EP Posterior Angle

0.51 0.31 0.13

0.28 0.44 0.06

0.05 0.07 0.53

EMG = electromyography; BET = balloon expulsion test; EP = evacuation proctography; Lying = left lateral position; Sitting = sitting position,

Dis Colon Rectum, September 1997

which of the two ARA measurements is the optimum one. Signs of anismus in all three tests (EMG in the left lateral position, BET in the left lateral position, and EP PARA) were detected in only one control subject (5 percent), in five incontinent patients (18 percenO, and in two constipated subjects (4 percent). Also, the number of positive tests did not significantly differ between the various groups. Therefore, constipation and/or obstructed defecation cannot be discriminated from other abnormalities solely based on the number of positive tests. Sixty-eight subjects (71 percent) w h o enrolled the second part of the study had evidence of anismus on EMG in the sitting position. Despite this finding, 26 of these subjects (38 percent) were able to pass the rectal balloon in the sitting position. Fifty-eight of these subjects (85 percent) had a normal EP based on PARA measurements, whereas 49 (72 percent) had a normal EP based on CARA measurements (Fig, 1). Conversely, of the 28 patients who showed a normal relaxation of the puborectalis muscle on EMG, 29 percent were unable to p a s s the balloon. PARA and CARA measurements revealed that, respectively, 7 and 18 percent of these subjects had radiologic evidence of anismus (Fig. 2). These findings indicate a p o o r agreement between the different tests. This is confirmed by the calculation of the kappa values (Table 4).

DISCUSSION In 1964, Wasserman s described four patients with obstructed defecation attributable to "a type of stenosis of the anorectum caused by a spasm of a component of the external ani sphincter muscle" and named it "puborectalis syndrome." Since then, a wide variety of appellations have been devised to describe this condition. The most frequently used terms are anismus, 9 spastic pelvic floor syndrome, 1~ and nonrelaxing puborectalis syndrome. ~1 Characteristic symptoms such as prolonged and repeated straining at stool, the necessity of manual assistance, the sensation of incomplete evacuation, and the need for suppositories and enemas are suggestive of this condition. Unfortunately, an almost identical pattern of symptoms is observed in patients with a large rectocele. Therefore, the history of the patient is inconclusive in establishing nonrelaxation of the pelvic floor during attempted evacuation. Although paradoxical contraction of the puborectalis muscle has been reported to be easily

EMG SITTING POSITION + R&I

1037

ANISMUS: FACT OR FICTION?

Vol. 40, No. 9

BET SITTING POSITION

I NN~

EMG SITTING POSITION + BALLOON

EP P O S T E R I O R ANGLE

93 8 %

85%

29%

29% -

96 2 %

915%

1ANISMUS

~lNo

ANISMUS

1ANISMUS

EMG SITTING POSITION

+

[] NO ANISMUS

EP CENTRAL ANGLE

BALLOON

72% 29%

28%

IANISMUS DNO ANISMUS

Figure 1. Agreement between abnormal electromyography (EMG) in the sitting position and the balloon expulsion test (BET) and evacuation proctography (EP). assessed by physical examination during straining, 12 most workers do not rely on palpation and advocate the use of specific tests to document anismus. Electromyography, evacuation proctography, and the balloon expulsion test are the most commonly used methods. Much controversy, however, exists among investigators relative to the optimum diagnostic test. No single method has been proven to be pathognomonic for anismus or superior to the others. This confusion about diagnostic modalities illustrates the lack of understanding of anismus. Rutter 13 first demonstrated electromyographic signs of anismus in patients with either a solitary rectal ulcer or descending perineum. Usually, the activity of the pelvic floor is recorded with a fine concentric needle electrode inserted in the puborectalis muscle. It has been stated that the inability to relax the pelvic floor during straining may be a response to fear of pain caused by the electrode. 14 It has been reported, however, that patients complaining of pain during the investigation with a conventional needle electrode also have a paradoxical sphincter reaction w h e n they

are investigated without pain using fine wire electrodes. 12 In most studies, EMG is performed with the patient in the left lateral position. Straining in this position after painful insertion of a needle and without a natural desire to defecate is unphysiologic. Duthie and Bartolo ~ found evidence of anismus on EMG recordings in 11 patients with constipation during attempted defecation on a c o m m o d e in the laboratory. However, during h o m e recordings, the puborectalis and the external sphincter muscles relaxed during straining in all but three patients. ~ These findings support the view that the inability to relax the pelvic floor, as assessed by EMG, might represent the inability to comply with the request in the unfamiliar and unphysiologic circumstances of the laboratory) Despite these limitations, EMG is considered to be the most specific test that provides the best assessment of puborectalis muscle activity during straining. 15 If anismus represents the principal cause of obstructed defecation, then increased EMG activity of the puborectalis muscle should be associated with a more acute ARA and subsequent failure to expel a rectal

1038

SCHOUTEN E T A L EMG SITTING POSITION

+

BET SITTING POSITION

BALLOON

Dis Colon Rectum, September 1997

EMG SITTING POSITION + RAI,I,OON

EP POSTERIOR ANGLE

1% "

71% -

71% -

93%

29%

"7%

IANISMUS [-qNO ANISMUS

1ANISMUS [ ] N O ANISMUS

EMG SITTING POSITION

+

EP CENTRAL ANGLE

BALLOON

82% 71% -

18%

IANISMUS [] NOANISMUS

Figure 2. Agreement between normal electromyography (EMG) in the sitting position and balloon expulsion test (BET) and evacuation proctography (EP). Table 4. Kappa Values of Different Tests

Electromyography Sitting Balloon expulsion test sitting

Evacuation proctography posterior angle Evacuation proctography central angle Sitting = sitting position.

0.30 0.05 0.07

balloon. Furthermore, these findings should be observed exclusively in patients with evacuation difficulties. Our study demonstrates that signs of anismus are not specific for constipation and/or obstructed defecation and that EMG, EP, and BET showed poor agreement. Our findings are in accordance with those of others. Jones e t aL 3 found electromyographic evidence of anismus in 76 percent of patients with constipation, 50 percent of patients with solitary rectal ulcer syndrome, and 48 percent of patients with anorectal pain. All patients with a solitary rectal ulcer had

obstructed defecation, whereas those with anorectal pain had a normal defecation pattern. These observations suggest that anismus is indeed a relatively nonspecific finding) Pezim and associates a6 reported that nearly 50 percent of their controls exhibited either a paradoxical increase in EMG activity or no suppression during straining. They concluded that "EMG is not helpful in identifying the etiology of constipation." Miller e t al. 5 could not demonstrate a consistent correlation between EMG activity during straining with changes in ARA and rectal emptying. Recently, Dahl and associates 6 reported that 13 of 14 patients with electromyographic evidence of anismus were able to expel an inflated balloon. The true prevalence of anismus in controls, based on EMG criteria, is yet unknown. Between 1985 and 1993, ten articles have been published regarding this subject.2, 16-24 In eight of these studies, EMG activity was recorded in the left lateral position. In two series of controls, EMG was performed while the controls attempted to pass a 50-ml balloon. In only three studies, none of the controls showed EMG evidence

Vol. 40, No. 9

ANISMUS: FACT OR FICTION?

of paradoxical contraction of the pelvic floor. 17' 18, 22 In the other studies, the prevalence of anismus varied from 12 to 61 percent. Based on these findings, Roberts e t aL 23 concluded that the prevalence of anismus is overestimated, if this p h e n o m e n o n is defined solely as recruitment of EMG activity. Therefore, they passed on to redefining anismus and suggested that the diagnosis should be based on three criteria: demonstration of puborectalis EMG recruitment of more than 50 percent, evidence of an adequate level of intrarectal pressure on straining, and presence of defective evacuation. With use of these "new" criteria, the prevalence of anismus a m o n g controls d r o p p e d from 30 to 5 percent! This scientific trick is rather curious and illustrates the confusion relative to the problem of anismus. The balloon expulsion test is another m e t h o d that is c o m m o n l y used to reach the diagnosis of anismus. This simple test has b e e n introduced by Preston and Lennard-Jones in 1985. 9 Since then, seven studies have b e e n conducted to investigate the ability of normal subjects to expel a water-filled rectal balloon. According to these studies, almost all controls were able to do so. 9' 18-20, 25-27 Based on these results, one might conclude that anismus is a rare p h e n o m e n o n in normal subjects. It is questionable, however, whether the inability to expel a balloon represents anismus. Recently, Dahl e t aL 6 reported that 13 of 14 patients with electromyographic signs of anismus were able to pass an inflated balloon. They concluded that the BET is not a useful marker of paradoxical contraction of the pelvic floor. Our study also demonstrates a lack of agreement b e t w e e n EMG and BET. Fleshman e t aL 11 studied the ability to expel a balloon inflated to 60 ml with air in a highly selected group of 21 patients with "nonrelaxation of the puborectalis muscle on defecography." The authors reported that balloon expulsion was accomplished in nine patients. Based on this finding, they concluded that anismus is overdiagnosed using defecography and that balloon expulsion in the sitting position is the best m e t h o d to diagnose nonrelaxing puborectalis muscle. This erroneous statement illustrates that the authors were unable to accept that their findings allow for only one conclusion: that the correlation between BET and defecography is extremely poor. Evacuation proctography is a relatively simple m e t h o d of investigating rectal evacuation and of measuring the ARA. This angle depends on the tone of the puborectalis muscle and can be defined as the angle b e t w e e n a line through the central axis of the anal

1039

canal, with either the central axis of the distal part of the rectum or a line drawn parallel to the posterior wall of the distal rectum. It is generally accepted that the ARA b e c o m e s more obtuse during attempted evacuation, because of relaxation of the puborectalis muscle. Failure to increase the ARA on straining sometimes associated with accentuation of the p u b o rectalis impression is considered to be an important radiologic sign of anismus. It has b e e n argued, however, that visual assessment of the ARA is rather subjective and, therefore, unreliable. 28-33 Until now, 12 reports have b e e n published regarding the prevalence of anismus, based on radiologic criteria, in controls. 18-2~176 In six of these studies, none of the controls s h o w e d radiologic features of anismus.lS-20, 37-39 In the other series, the prevalence of anismus varied b e t w e e n 5 and 50 percent. 32-36' 4o If the failure to increase the ARA during attempted defecation represents anismus, then this p h e n o m e n o n should be associated with increased EMG activity and subsequent failure to expel a balloon. Kuijpers and Bleijenberg reported an excellent correlation b e t w e e n EMG and EP. 1~ 41 Until now, n o b o d y has b e e n able to reproduce such an excellent correlation b e t w e e n EMG and EP. 6' 11, 15, 19, 20, 24, 42, 43 The efficacy of biofeedback has b e e n used as an argument to support the clinical significance of anismus. Loening-Baucke 44 studied 38 children presenting with chronic constipation and encopresis. All of these children s h o w e d abnormal contraction of the pelvic floor during straining. Twenty-eight children learned to relax their pelvic floor. Despite this beneficial effect of biofeedback, 14 of these children did not recover from constipation. Similar findings have b e e n reported by others. 45-47 These observations are not in accordance with the assumption that anismus is the principal cause of obstructed defecation and that biofeedback is successful solely because it corrects the paradoxical contraction of the pelvic floor. Loening-Baucke 44 also reported that the nonrecovered patients w h o learned to relax their pelvic floor had significantly decreased rectal and anal responsiveness to rectal distention c o m p a r e d with recovered patients. These findings do suggest that impaired rectal sensitivity and decreased rectal motility might play a role in constipation and obstructed defecation. This view is supported by Lubowski and coworkers, 48 w h o suggested, based on scintigraphic studies, that "obstructed defecation m a y occur in some patients as a result of a disorder of colonic function rather than a disorder of the rectum or the pelvic floor muscles."

1040

SCHOUTEN E T A L

CONCLUSION The results of the present study indicate that signs o f anismus are a nonspecific finding. Based o n the a s s u m p t i o n that EMG in the sitting position is the ideal test for the diagnosis of anismus, it can be c o n c l u d e d that the a g r e e m e n t of the other two tests (EP a n d BET) is poor. Therefore, n o single test can be considered to be optimum. Based o n the present study and other findings, it might be possible, in our opinion, that anismus is fiction!

12.

13. 14. 15.

ACKNOWLEDGMENTS The authors thank J. Meulstee, M.D., Marijke de Waart, and Lya A n g e n e n t of the D e p a r t m e n t of Neur o p h y s i o l o g y for excellent technical assistance.

16.

17.

REFERENCES 1. Duthie GS, Bartolo DC. Anismus: the cause of constipation? Results of investigation and treatment. World J Surg 1992;16:831-5. 2. Barnes PR, Lennard-Jones JE. Function of the striated anal sphincter during straining in control subjects and constipated patients with a radiologically normal rectum or idiopathic megacolon. Int J Colorectal Dis 1988; 3:207-9. 3. Jones PN, Lubowski DZ, Swash M, Henry MM. Is paradoxical contraction of the puborectalis muscle of functional importance? Dis Colon Rectum 1987;30:667-70. 4. Wexner SD, Marchetti F, Salanga VD, Corredor C, Jagelman DG. Neurophysiologic assessment of the anal sphincters. Dis Colon Rectum 1991;34:606-12. 5. Miller R, Duthie GS, Bartolo DC, Roe AM, LockeEdmunds J, McC Mortensen NJ. Anismus in patients with normal and slow transit constipation. Br J Surg 1991;78:690-2. 6. Dahl J, Lindquist BL, Tysk C, Leissner P, Philipson L, J/~rnerot G. Behavioral medicine treatment in chronic constipation with paradoxical anal sphincter contraction. Dis Colon Rectum 1991;34:769-76. 7. Ginai AZ. Technical report: evacuation proctography (defecography) a new seat and method of examination. Clin Radiol 1990;42:214-6. 8. Wasserman IF. Puborectalis syndrome (rectal stenosis due to anorectal spasm). Dis Colon Rectum 1964;7: 87-98. 9. Preston DM, Lenmird-Jones JE. Anismus in chronic constipation. Dig Dis Sci 1985;30:413-8. 10. Kuijpers HC, Bleijenberg G. The spastic pelvic floor syndrome: a cause of constipation. Dis Colon Rectum 1985;28:669-72. 11. Fleshman JW, Dreznik Z, Cohen E, Fry RD, Kodner IJ. Balloon expulsion test facilitates diagnosis of pelvic

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

Dis Colon Rectum, September 1997

floor outlet obstruction due to nonrelaxing pnborectalis muscle. Dis Colon Rectum 1992;35:1019-25. Johansson C, Nilsson BY, Holmstrom B, Dolk A. Is paradoxical sphincter reaction provoked by needle electrode electromyography? Dis Colon Rectum 1991; 34:1109-12. Rutter KR. Electromyographic changes in certain pelvic floor abnormalities. J R Soc Med 1974;67:53-6. Keighley MR, Shouler P. Outlet syndrome: is there a surgical option? J R Soc Med 1984;77:559453. Miller R, Duthie GS, Bartolo DC, Roe AM, LockeEdmunds J, Mortensen NJ. Anismus in patients with normal and slow transit constipation. Br J Surg 1991;78: 690-2. Pezim ME, Pemberton JH, Levin KE, Litchy WJ, Phillips SF. Parameters of anorectal and colonic motility in health and in severe constipation. Dis Colon Rectum 1993;36:484-91. Womack NR, Williams NS, Holmfleld JH, Morrison JF, Simpkins KC. New method for the dynamic assessment of anorectaI function in constipation. BrJ Surg 1985;72: 994-8. Shouler P, Keighley MR. Changes in colorectal function in severe idiopathic chronic constipation. Gastroenterology 1986;90:414-20. Read NW, Timms JM, Barfield LJ, Donnelly TC, Bannister JJ. Impairment of defecation in young women with severe constipation. Gastroenterology 1986;90:53450. Roe AM, Bartolo DC, Mortensen NJ. Slow transit constipation: comparison between patients with or without previous hysterectomy. Dig Dis Sci 1988;33:115943. Kerrigan DD, Lucas MG, Sun WM, Donnelly TC, Read NW. Idiopathic constipation associated with impaired urethrovesical and sacral reflex function. BrJ Surg 1989; 76:748-51. Johansson C, Ihre T, Holmstr6m B, Nordstrom E, Dolk A, Broden G. A combined electromyographic and cineradiologic investigation in patients with defecation disorders. Dis Colon Rectum 1990;33:1009-13. Roberts Jp, Womack NR, Hallan RI, Thorpe AC, Williams NS. Evidence from dynamic integrated proctography to redefine anismus. Br J Surg 1992;79:1213-5. Lubowski DZ, King DW, Finlay IG. Electromyography of the pubococcygeus muscles in patients with obstructed defecation. Int J Colorectal Dis 1992;7:184-7. Barnes PR, Lennard-Jones JE. Balloon expulsion from the rectum in constipation of different types. Gut 1985; 26:1049-52. Turnbull GK, Lennard-Jones JE, Bartram CI. Failure of rectal expulsion as a cause of constipation: why fibre and laxatives sometimes fail. Lancet 1986;1:767-9. Lestar B, Penninckx FM, Kerremans RP. Defecometry: a new method for determining the parameters of rectal evacuation. Dis Colon Rectum 1989;32:197-201. Ferrante SL, Perry RE, Schreiman JS, Cheng SC, Frick

Vol. 40, No. 9

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

ANISMUS: FACT OR FtCTION?

MP. The reproducibility of measuring the anorectal angle in defecography. Dis Colon Rectum 1991;34:51-5. Penninckx F, Debmyne C, Lestar B, Kerremans R. Observer variation in the radiological measurement of the anorectal angle. Int J Colorectal Dis 1990;55:94-7. Penninckx F, Debruyne C, Lestar B, Kerremans R. Intraobserver variation in the radiological measurement of the anorectal angle. Gastrointest Radiol 1991;16:73-6. Yoshioka K, Pinho M, Ortiz J, Oya M, Hyland G, Keighley MR. How reliable is measurement of the anorectal angle by videoproctography? Dis Colon Rectum 1991; 34:1010-3. Shorvon PJ, McHugh S, Diamant NE, Somers S, Stevenson GW. Defecography in normal volunteers: results and implications. Gut 1989;30:1737-49. Bartram CI, Turnbull GK, Lennard-Jones JE. Evacuation proctography: an investigation of rectal expulsion in 20 subjects without defecatory disturbance. Gastrointest Radiol 1988;13:72430. Turnbull GK, Bartram CI, Lennard-Jones JE. Radiologic studies of rectal evacuation in adults with idiopathic constipation. Dis Colon Rectum 1988;31:190-7. Bartolo DC, Roe AM, Virjee J, McMortensen NJ, LockeEdmunds JC. An analysis of rectal morphology in obstructed defecation. Int J Colorectal Dis 1988;3:17-22. Goei R, van Engelshoven J, Schouten H, Baeten C, Stassen C. Anorectal function: defecographic measurement in asymptomatic subjects. Radiology 1989;173: 137-41. Wald A, Camana BJ, Freimanis MG, Bauman DH, Hinds JP. Contributions of evacuation proctography and anorectal manometry to evaluation of adults with constipation and defecatory difficulty. Dig Dis Sci 1990;35: 481-7. Infantino A, Masin A, Pianon P, et al. Role of proctog-

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

1041

raphy in severe constipation. Dis Colon Rectum 1990; 33:707-12. Selvaggio F, Pesce G, Scotto Di Carlo E, Maffettone V, Canonico S. Evaluation of normal subjects by defecographic technique. Dis Colon Rectum 1990;33:689-702. Freimanis MG, Wald A, Caruana B, Bauman DH. Evacuation proctography in normal volunteers. Invest Radiol 1991;26:581-5. Kuijpers HC. Application of the colorectal laboratory in diagnosis and treatment of functional constipation. Dis Colon Rectum 1990;33:35-9. Fink RL, Roberts LJ, Scott M. The role of manometry, electromyography and radiology in the assessment of intractable constipation. Aust N Z J Surg 1991;61: 959-64. Jorge JM, Wexner SD, Ger GC, Salanga VD, NoguerasJJ, Jagelman DG. Cinedefecography and electromyography in the diagnosis of nonrelaxing puborectalis syndrome. Dis Colon Rectum 1993;36:668-76. Loening-Baucke V. Persistence of chronic constipation in children after biofeedback treatment. Dig Dis Sci 1991;36:153-60. Keck JO, Staniunas RJ, Coller JA, et al. Biofeedback training is useful in fecal incontinence but disappointing in constipation. Dis Colon Rectum 1994;37:1271-6. Turnbull GK, Ritvo PG. Anal sphincter biofeedback relaxation treatment for women with intractable constipation symptoms. Dis Colon Rectum 1992;35:530-6. Van der Plas RN, Benninga MA, Btiller HA, et al. Biofeedback training in treatment of childhood constipation: a randomised controlled study. Lancet 1996;348: 776--8. Lubowski DZ, Meagher AP, Smart RC, Butler SP. Scintigraphic assessment of colonic function during defaecation. Int J Colorectal Dis 1995;10:91-3.