Electromyography of the pubococcygeus muscles in patients with obstructed defaecation

Early recognition of pelvic floor dyssynergia and colorectal assessment in Parkinson's disease associated with bowel dysfunction

AIM

Slow colonic transit time (CTT) and pelvic floor dyssynergia (PFD) are major contributors to constipation in patients with Parkinson's disease (PD). However, no symptom survey yet exists that effectively differentiates the contributing aetiologies. The significance of individual pelvic floor musculature behaviours and their relationship with colorectal dysmotility in constipated patients with PD are still controversial and need further clarification. We aimed to investigate how differentiated constipation-related symptoms of PD patients with constipation may identify constipation groupings and to register the pathophysiological features of the pelvic musculature.

METHOD

Our subjects undertook CTT, defaecography and the Knowles-Eccersley-Scott Symptom questionnaire. The pathological aetiologies were categorized as group 1 (slow CTT) and/or group 2 (puborectalis syndrome) and/or group 3 (pubococcygeus syndrome), in accordance with the CTT and defaecography results.

RESULTS

Constipation-related symptoms such as incomplete evacuation and defaecation difficulty yielded high post-test probabilities (81% and 88%, respectively) in groups 3 and 2, but a low post-test probability in group 1 (58%). Changes in the anorectal angle and perineum descent during straining were significantly correlated with CTT (r = 0.57 and r = 0.61, respectively) and with each other (r = 0.82).

CONCLUSION

Our findings that neural control of the puborectalis and pubococcygeus, along with colorectal peristalsis, were in a similar state of degeneration is key information that should assist physicians to instigate more effective management for colonic dysmotility or PFD.

Is dynamic two-dimensional anal ultrasonography useful in the assessment of anismus? A comparison with manometry

CONTEXT

Anismus is a prevalent functional cause of outlet delay. It is characterized by symptoms of obstructed defecation associated with paradoxical contraction of the pelvic floor muscles.

OBJECTIVE

To evaluate the ability of two dimensional anal ultrasonography to identify anismus patients with paradoxical contraction or normal relaxation, comparing findings with manometric measurements.

METHODS

Forty-nine women presenting with outlet delay and a mean validated Wexner constipation score of 13.5 were included in a prospective study. Following screening with anal manometry, the patients were assigned to one of two groups: G-I -with normal relaxation and G-II -patients with anismus. Dynamic anorectal ultrasonography was used to quantifier the movement of the puborectalis muscle and to measure changes in the angle between two converging lines drawn from the 3 o'clock and the 9 o'clock positions of the endoprobe circumference to the internal border of the puborectalis muscle. The angle decreases during straining in patients with normal relaxation, but increases in patients with anismus. The agreement between the two techniques was verified with the Kappa index.

RESULTS

In manometry, during straining the anal canal pressure decreased by 41.3% in G-I and increased by 168.6% in G-II, indicating a diagnosis of anismus for the second group. In US, during straining, the angle produced by the movement of the puborectalis muscle decreased from 63 ± 1.31 to 58 ± 1.509 degrees (P = 0.0135) in 23 of the 30 patients in G-I, indicating normal relaxation, and increased from 66 ± 0.972 to 72 ± 0.897 degrees (P = 0.0001) in 16 of the 19 patients in G-II, indicating anismus. The index of agreement between manometry and two dimensional anal ultrasonography was moderate: 77% (23/30) for G-I and 84% (16/19) for G-II.

CONCLUSION

Two-dimensional dynamic anal ultrasonography showed similar results previously suggested by anal manometry at identifying patients with normal relaxation or paradoxical contraction.

Perineal descent and patients' symptoms of anorectal dysfunction, pelvic organ prolapse, and urinary incontinence

Introduction and hypothesis

The aim of this dynamic magnetic resonance (MR) imaging study was to assess the relation between the position and mobility of the perineum and patients’ symptoms of pelvic floor dysfunction.

Methods

Patients’ symptoms were measured with the use of validated questionnaires. Univariate logistic regression analyses were used to study the relationship between the questionnaires domain scores and the perineal position on dynamic MR imaging, as well as baseline characteristics (age, body mass index, and parity).

Results

Sixty-nine women were included in the analysis. Only the domain score genital prolapse was associated with the perineal position on dynamic MR imaging. This association was strongest at rest.

Conclusions

Pelvic organ prolapse symptoms were associated with the degree of descent of the perineum on dynamic MR imaging. Perineal descent was not related to anorectal and/or urinary incontinence symptoms.

Neurophysiology in neurourology

The bladder has only two essential functions. It stores and periodically empties liquid waste. Yet it is unique as a visceral organ, allowing integrated volitional and autonomous control of continence and voiding. Normal function tests the integrity of the nervous system at all levels, extending from the neuroepithelium of the bladder wall to the frontal cortex of the brain. Thus, dysfunction is common with impairment of either the central or peripheral nervous system. This monograph presents an overview of the neural control of the bladder as it is currently understood. A description of pertinent peripheral anatomy and neuroanatomy is provided, followed by an explanation of common neurophysiological tests of the lower urinary tract and associated structures, including both urodynamic and electrodiagnostic approaches. Clinical applications are included to illustrate the impact of nervous system dysfunction on the bladder and to provide indications for testing.

Evaluation of the paradoxical sphincter contraction by a strain/squeeze index in constipated patients

PURPOSE

One finding in patients with constipation is the paradoxical puborectalis contraction, i.e. , activation of the sphincter muscles during straining instead of relaxation. The aims of this study were to evaluate the importance of needle placement in sphincter-electromyography and to evaluate a strain/squeeze index in constipated patients and control subjects.

METHODS

We investigated consecutively 194 constipated patients and 16 control subjects with integrated electromyography during straining and squeezing and calculated a strain/squeeze index. The examination was performed in the puborectalis and in the external anal sphincter muscle through hook-electrodes.

RESULTS

There was a strong correlation between indices in the puborectalis muscle and in the external anal sphincter muscle (r = 0.70-0.80, P < 0.001). Forty-seven patients (24 percent) had a mean index of greater than 50 compared with none in the control group (P = 0.01). Mean overall index in patients was 24 (range, 0-306) vs. 18 (range, 0-45) in controls (P = 0.12). Patients with an index greater than 50 had impaired rectal evacuation (P < 0.001), increased threshold for urge (P < 0.05), and tended to have fewer stools (P = 0.06).

CONCLUSION

Quantification of paradoxical contraction in the puborectalis and external anal sphincter with a strain/squeeze index differentiates patients in whom paradoxical activity may be a cause of constipation. An index above 50 may be of pathologic significance. Correlations between activity in the puborectalis and external anal sphincter muscle were strong which suggests that investigation in one of them is sufficient.

Abnormal predefecatory colonic motor patterns define constipation in obstructed defecation

BACKGROUND & AIMS

The pathophysiology of constipation in the syndrome of obstructed defecation is unknown. Using 24-hour pancolonic manometric recordings of the unprepared colon to record basal pressures and spontaneous defecation episodes, we tested the hypothesis that the frequency, timing, or spatial distribution of propagating colonic pressure waves is abnormal in patients with obstructed defecation.

METHODS

In 11 patients with obstructed defecation and 16 healthy controls, pressures were recorded using a nasocolonic catheter that was positioned such that 16 recording sites spanned the unprepared colon at 7.5-cm intervals.

RESULTS

The overall frequency of propagating sequences (PS) in the colon did not differ between patients and controls. When compared with controls, patients had a significant increase in the frequency of retrograde and antegrade PS (P < 0.05) in the left colon and a significant reduction in the amplitude of propagating pressure waves throughout the entire colon (P < 0.03). Defecation occurred in 6 of 11 patients and 9 of 16 controls. In the 15 minutes before defecation, controls showed a highly significant increase in frequency (P = 0.001) and amplitude (P = 0.01) of PS. In contrast, patients did not demonstrate this or the typical spatiotemporal organization of PS normally observed before expulsion of stool.

CONCLUSIONS

Patients with obstructed defecation lack the normal predefecatory augmentation in frequency and amplitude of propagating pressure waves and lack the normal stereotypic spatiotemporal patterning of colonic pressure waves that would normally culminate in effective expulsion of stool.

Electromyography of the pelvic floor musculature in the assessment of obstructed defecation symptoms

PURPOSE

The purpose of this study was to use electromyography to examine the behavior of the external sphincter, puborectalis muscle, and pubococcygeus muscle during attempted defecation in patients with symptoms of obstructed defecation and in normal subjects to highlight differences of clinical significance.

METHODS

A total of 35 patients (31 females) aged 20 to 80 (mean, 53.7 +/- 13.3) years with unprepared bowel who had normal colon transit time and obstructed defecation symptoms and 12 voluntary control subjects (7 females) aged 23 to 68 (mean, 48 +/- 11.5) years underwent an electromyography evaluation of the activity of the external sphincter, puborectalis muscle, and pubococcygeus muscle during attempted defecation. The patients were also examined in separate sessions with defecography and anal manometry.

RESULTS

During attempted defecation, puborectalis muscle and external sphincter always reacted in the same manner. When evaluated with pubococcygeus muscle, three main patterns of activity were observed either in patients or in controls: 1) coordinated activation pattern; 2) coordinated inhibition pattern; and 3) uncoordinated or equivocal pattern: activation of pubococcygeus muscle with inhibition of puborectalis muscle/external sphincter, activation followed by inhibition of the three muscles, and activation followed by inhibition of pubococcygeus muscle and no change in the others. We never observed activation of puborectalis muscle/external sphincter concomitant with inhibition of pubococcygeus muscle. The inhibitory coordinated pattern occurred significantly (P = 0.01) more frequently in controls than in patients. These subjects also presented a significantly (P = 0.01) lower frequency of pubococcygeus muscle inhibition.

CONCLUSIONS

Either activation or inhibition appears as a physiological behavior, possibly adopted in different circumstances, of the pelvic floor muscles during attempted defecation. The higher prevalence of coordinated inhibitory patterns in normal subjects and the lower frequency of pubococcygeus muscle inhibition in patients with symptoms of obstructed defecation, however, suggests that a loss of inhibition capacity progressing from pubococcygeus muscle to puborectalis muscle/external sphincter muscles could determine the insurgence of obstructed defecation symptoms in some subjects, who should therefore benefit from biofeedback retraining aimed at reacquisition of the inhibition capacity of all muscles of the pelvic floor during defecation.

Surgical treatment of constipation and fecal incontinence

Fecal incontinence is a disabling and distressing condition. Many patients are reluctant to discuss the condition with a physician. A thorough history, good physical examination, and detailed anorectal physiologic investigations can help in the therapeutic decision-making algorithm. Patients with isolated anterior sphincter defects are candidates for overlapping repair. In the presence of unilateral or bilateral pudendal neuropathy, the patient should be counseled preoperatively regarding a [table: see text] lower anticipation of success. If the injury occurred shortly before the planned surgery and neuropathy is present, it may be prudent to wait because neuropathy sometimes can resolve within 6 to 24 months of the injury. Pudendal nerve study may help determine surgical timing. An anterior sphincter defect combined with a rectovaginal fistula can be approached by overlapping sphincter repair and a concomitant transanal advancement flap. Patients who had undergone multiple such procedures may benefit from concomitant fecal diversion at the time of repeat sphincter repair. Patients with global or multifocal sphincter injury may be candidates for a neosphincter procedure. The stimulated graciloplasty and artificial bowel sphincter are reasonable options. In the absence of the availability of these techniques or because of financial constraints, consideration could be given to bilateral gluteoplasty or unilateral or bilateral nonstimulated graciloplasty. The postanal repair still serves a role in patients with isolated decreased resting pressures with or without neuropathy or external sphincter injury with minimal degrees of incontinence. Biofeedback and the Procon device may play a role in these patients. Lastly, fecal diversion must be considered as a means of improving the quality of life because the patient can participate in the activities of daily living without the fear of fecal incontinence.

Identification of patients likely to benefit from biofeedback for outlet obstruction constipation

BACKGROUND

Biofeedback for outlet obstruction constipation has a varying success rate. The aim of this study was to identify which patients are likely to respond to biofeedback.

METHODS

Thirty patients with severe outlet obstruction constipation were treated by a specialist nurse using three or four sessions of visual and auditory feedback of anal sphincter pressures. All patients were assessed by evacuating proctography, whole-gut transit studies and anorectal physiology before treatment.

RESULTS

Two patients did not complete the course of biofeedback. Nine patients improved. Before treatment these patients had predominantly normal anorectal physiology and were all able to open the anorectal angle at evacuating proctography. Nineteen patients did not improve, of whom only three had no measured abnormality other than inability to empty the rectum. Ten of these patients had abnormal anorectal physiology which may have been due to previous vaginal delivery.

CONCLUSION

Biofeedback for outlet obstruction constipation is more likely to be successful in patients without evidence of severe pelvic floor damage.

Results of biofeedback in constipated patients: a prospective study

PURPOSE

The aims of this study were to assess the results of biofeedback treatment in constipated patients and to identify variables that might be used to predict the outcome.

METHOD

Twenty-eight patients (5 men; median age, 46 (range, 22-72) years) with any degree of paradoxical activation measured with thin hook needle electromyography in the external sphincter or puborectalis muscle were included. The symptom duration varied between 1 and 30 (median, 9) years. The patients had eight outpatient training sessions with electromyography-based audiovisual feedback. All patients were followed up prospectively with a validated bowel function questionnaire from which a symptom index was created.

RESULTS

At three months, nine patients had no improvement and underwent other treatments. The remaining 19 patients were followed up for a median of 14 (range, 12-34) months. Twelve patients (43 percent) stated they had improved rectal emptying. A good result was associated with increased stool frequency (P < 0.05), improved symptom index (P < 0.01), and reduction of laxative use (P < 0.05). A long symptom duration, a high pretreatment symptom index, and laxative use were related to a poor result (P < 0.01-0.05). The improved group had less perineal descent (P < 0.05), and a prominent puborectalis impression on defecography tended to be more common (P = 0.06).

CONCLUSION

With the use of wide inclusion criteria, biofeedback was successful in 43 percent of patients, with a treatment effect lasting at least one year. The results suggest that biofeedback should be used as the initial treatment of constipated patients with a paradoxical puborectalis contraction.

Anismus: fact or fiction?

PURPOSE

Although anismus 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 the 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, we doubt the clinical significance of anismus.

Viscous fluid expulsion in the evaluation of the constipated patient

PURPOSE

The aim of this study was to evaluate a viscous fluid expulsion test as a method for quantifying rectal outlet obstruction.

METHODS

We examined the ability of 30 severely constipated patients and 40 healthy control subjects to expel a viscous fluid simulating feces.

RESULTS

Constipated patients with defecographic rectal retention expelled a significant lower viscous fluid volume compared with controls (P < 0.0001). Considering the viscous fluid expulsion test to be positive if the patient expelled less than 160 ml of fluid (lower 95 percent confidence value in healthy controls) and using the presence of defecographic rectal outlet obstruction as a reference, the predictive value of a negative viscous fluid expulsion test was 100 percent, the predictive value of a positive test was 67 percent, and sensitivity and specificity was 100 percent and 82 percent, respectively. The viscous fluid test identified symptomatic outlet obstruction in almost twice as many patients as did defecography. Some patients, however are-despite their obstructive symptoms-able to evacuate their rectum when examined in the laboratory.

CONCLUSION

The viscous fluid expulsion test is a simple, reproducible, nonionizing, and low-cost method of quantifying rectal outlet obstruction. A positive test result should lead to a defecography, whereas a negative test result renders defecography dispensable and spares the patient from pelvic radiation.

Role of defecography in predicting clinical outcome of rectocele repair

PURPOSE

The aim of this study was to evaluate the role of defecography in predicting clinical outcome of rectocele repair.

METHODS

Between January 1988 and July 1994, 74 consecutive patients (median age, 54 (range, 35-81) years) with a rectocele and symptoms of obstructed defecation were studied prospectively. After preoperative evaluation by a standardized questionnaire, physical examination, and defecography, a combined transvaginal/transanal rectocele repair was performed. At follow-up, all patients had defecography. Long-term results were qualified by an independent observer after a median follow-up of 58 (range, 14-89) months as "excellent," "good," or "poor."

RESULTS

Rectocele repair was considered excellent in 37 patients and good in 13 patients. Defecography six months after surgery did not show persistent or recurrent rectocele in any of the patients. Size of the rectocele, barium-trapping in the rectocele, internal intussusception, rectal evacuation, and perineal descent did not appear to influence clinical outcome. Radiologic evidence of anismus did not correlate with long-term results of rectocele repair.

CONCLUSIONS

Combined transanal/transvaginal repair of rectocele is an efficient therapy in patients with obstructed defecation. Various defecographic parameters (size of rectocele, internal intussusception, rectal evacuation, perineal descent, radiologic signs of anismus) do not appear to influence clinical outcome of surgery. The main value of defecography is the objective demonstration of rectocele and any associated abnormalities such as an enterocele preoperatively and again in objective assessment of the postoperative results.

[Defecation flowmetry. A new study technique for evaluating the evacuation function of the rectum]

In a prospective study carried out on 78 patients with chronic constipation (31, with slow transit, 47 with obstructive defecation disorders) the evacuation function of the rectum during defecation was assessed by defecoflowmetry. These patients were compared to a control group of normal volunteers (n = 32). The following parameters were evaluated: defecation and retention volume, defecation fraction, defecation time, maximum flow, mean flow rate and time to maximum flow. As expected, there was no difference in evacuation function between the group of patients with slow transit and the control group. Significant differences, however, existed between the two types of constipation, as well as between obstructive defecation disease and controls, regarding all parameters mentioned above. Evacuation function depends neither on rectal neck pressure nor on intrarectal pressure. In patients with obstructive defecation disorders, three subgroups were discernable: one with prolonged time of defecation and satisfactory evacuation, one with prolonged time of defecation and poor evacuation, and one small group of patients who were not able to defecate. Each group is based on a different underlying pathomechanism. We conclude that changes in evacuation function of the rectum refer either to volume or to time of defecation, or to both. Changes are found only in obstructive type constipation, not in slow transit constipation. Therefore, defeconflowmetry as a dynamic procedure can be used in screening for the classification of chronic constipation.

Clinical and physiologic effects of biofeedback in outlet obstruction constipation

PURPOSE

We report the results of biofeedback (BF) on patients with outlet obstruction defecation (OOC), including those with and without measurable paradoxical puborectalis contractions (PP). Clinical and anorectal physiologic parameters (ARP) were assessed one week before and after a standardized course of BF.

METHODS

Sixty-two consecutive patients (24 men, 38 women; mean age, 48 (standard error of the mean, 2.3) years) were recruited. All had persistent constipation despite six weeks of dietary fiber supplements. Colonic inertia was excluded by transit marker studies. Defecating proctography excluded anatomic abnormalities causing outlet obstruction. Patients underwent four outpatient sessions of biofeedback, each session lasting one hour.

RESULTS

After BF, 56 patients (90.3 percent) were subjectively improved. Frequency of spontaneous bowel movements were significantly increased (P = 0.003). Frequency of laxative-induced (P = 0.004) and enema-induced (P = 0.005) stools were reduced. Anal resting (P = 0.04) and squeeze (P = 0.002) pressures were increased. Number of patients with PP was reduced from 40 to 31 (P = 0.004). Presence of PP did not affect response to BF. There were no differences in ARP between the 56 patients who improved and the 6 who did not. There were no side effects or clinical regressions after a mean follow-up of 14.9 (standard error of the means, 0.9) months.

CONCLUSIONS

BF effectively treated OOC in 90.3 percent, regardless of PP. Anal pressures were increased, and PP was decreased.

Rectal mucosal electrosensitivity - what is being tested?

The results of rectal mucosal electrosensitivity (RME) testing have been used to support theories regarding the aetiology of both idiopathic constipation and bowel dysfunction following rectopexy. The aim of this study was to assess the validity of tests of RME. Sixty-eight patients, comprising three groups (group 1: 50 patients undergoing assessment in the Anorectal Physiology Unit, group 2: 10 patients with coloanal or ileoanal anastomosis, group 3: 8 patients with a stoma) underwent mucosal electrosensitivity testing, with the threshold stimulus required to elicit sensation being recorded. In addition the RME was measured in groups 1 and 2 when placing the electrode, mounted on a catheter with a central wire, against the anterior, posterior, right and left rectal or neorectal walls. To asses the influence on this test of loss of mucosal contact due to faeces, a further 8 cases with a normal rectum had RME performed with and without a layer of water soaked gauze around the electrode to stimulate faeces and prevent the electrode from making contact with the rectal mucosa. There was marked variance in the sensitivity of the different regions of rectal wall tested (P < 0.001). In group 1 patients the mean sensitivities were: central 36.6 mA, anterior 27.4 mA, posterior 37.9 mA, right 22.3 mA and left 25.6 mA. This circumferential variation suggests that the pelvic floor rather than rectal mucosa was being stimulated. All patients in group 2 had recordable sensitivities, and the mean sensitivity threshold was significantly higher than group 1 patients in the central (P = 0.03), right (P = 0.03) and left (P = 0.007) positions. In group 3 the sensitivity was greater within the stoma at the level of the abdominal wall muscle than intra-abdominally or subcutaneously, again suggesting an extra-colonic origin of the sensation. The sensitivity threshold was significantly greater with the electrode wrapped in gauze (P < 0.01), and loss of mucosal contact was not detected by the EMG machine. Therefore RME testing would seem not to measure mucosal sensitivity, and is probably influenced by the presence of faeces.

Obstructed defecation: current status of pathophysiology and management

Obstructed defecation poses a challenging clinical problem and in many patients presenting with this syndrome the underlying pathophysiology cannot be determined. Up to now, attempts to diagnose and treat obstructed defecation (anismus) have focused on the function of the somatic pelvic floor musculature surrounding the anorectum, and concepts such as 'puborectalis paradox' and 'spastic pelvic floor' have gained widespread acceptance despite there being no objective data to support such concepts. New evidence showing that defecation is an integrated process of colonic and rectal emptying suggests that anismus may be much more complex than a simple disorder of the pelvic floor muscles. In a small number of patients obstructed defecation is caused by a more simple mechanism, such as internal sphincter hypertonia or a large rectocele, which is easily corrected surgically. Careful selection of patients for treatment, based on identifying the underlying pathophysiological disorder, is emphasized.

Scintigraphic assessment of colonic function during defaecation

The aim of this study was to develop a method by which rectal and colonic activity could be examined during defaecation under physiological conditions, in order to evaluate whether the colon plays a role in defaecation. Subjects presented to the Nuclear Medicine department on the day following ingestion of oral In-111 labelled DTPA, when they developed the normal urge to defaecate. Defaecation took place in a private room while dynamic scintigraphy of the rectum and colon was recorded. Fourteen subjects were studied (8 normal subjects, 4 with constipation, 2 with irritable bowel syndrome). In 13 subjects the left colon was visualized during defaecation and emptying was clearly observed in 12. The right colon was visualised in 11 subjects and emptying was seen in 7. Mean percentage segmental evacuation was right colon 20%, left colon 32% and rectum 66%. Colonic emptying occurs during defaecation, which is not a process of rectal evacuation only. This has implications for the understanding of the pathophysiology of obstructed defaecation.

[Electromyographic activity of the external anal sphincter muscle and the puborectal muscle in the defecation test in patients with obstructive defecation disorders]

In a prospective electromyographic and manometric study on 23 women (average age 52 years) with obstructive defecation disorder the activity of the external anal sphincter muscle and the puborectal muscle was investigated at rest and during contraction and straining. The control group consisted of 22 healthy women with an average age of 53 years. The main aim of the study was to investigate the functioning of the two muscles during simulated defecation (maximum strain) and to examine any changes in the pressure ratio in the rectum and the anal canal during this stimulation. There were no significant differences in the resting pressure, the contraction pressure and the straining pressure (in the rectum and the anal canal) between the two groups. The functioning of the puborectal muscle and the external anal sphincter muscle was largely the same in both the study group and the control group. No statistically significant differences were found between the two groups except in the amplitude of contraction. When we tried to list the change in the activity of the muscle as an index of anism, we were not able to objectify such a change for either the external anal sphincter muscle or the puborectal muscle. We therefore conclude that the increase in the activity of the voluntary muscle of the pelvic floor observed on electromyography during defecation does not indicate a pathologic condition but is a functional state.