Anal ultra slow waves: a smooth muscle phenomenon associated with dyschezia

Review of the indications, methods, and clinical utility of anorectal manometry and the rectal balloon expulsion test

BACKGROUND

Anorectal manometry (ARM) comprehensively assesses anorectal sensorimotor functions.

PURPOSE

This review examines the indications, techniques, interpretation, strengths, and weaknesses of high-resolution ARM (HR-ARM), 3-dimensional high-resolution anorectal manometry (3D-HR-ARM), and portable ARM, and other assessments (i.e., rectal sensation and rectal balloon expulsion test) that are performed alongside manometry. It is based on a literature search of articles related to ARM in adults. HR-ARM and 3D-HR-ARM are useful for diagnosing defecatory disorders (DD), to identify anorectal sensorimotor dysfunction and guide management in patients with fecal incontinence (FI), constipation, megacolon, and megarectum; and to screen for anorectal structural (e.g., rectal intussusception) abnormalities. The rectal balloon expulsion test is a useful, low-cost, radiation-free, outpatient assessment tool for impaired evacuation that is performed and interpreted in conjunction with ARM. The anorectal function tests should be interpreted with reference to age- and sex-matched normal values, clinical features, and results of other tests. A larger database of technique-specific normal values and newer paradigms of analyzing anorectal pressure profiles will increase the precision and diagnostic utility of HR-ARM for identifying abnormal mechanisms of defecation and continence.

A new method for assessing anal distensibility with a barostat and magnetic resonance imaging in healthy and constipated women

OBJECTIVES

Defecation requires relaxation of the internal and external anal sphincters. High anal resting pressure is associated with painful constipation, defecatory disorders, and increased healthcare utilization in constipated patients; the mechanisms are unclear. Perhaps patients with a high anal resting pressure have a less distensible canal, which impedes defecation.

METHODS

In 50 of 64 participants (33 healthy and 17 constipated women), anal pressures and distensibility were measured, respectively, with manometry and balloon distention combined with magnetic resonance imaging; rectal balloon expulsion time (BET) was also studied.

RESULTS

The BET (P = .006) was longer, and the mean (SD) rectoanal pressure gradient (-58[40] vs -34[26] mm Hg, P = .03) was more negative in constipated than healthy women; anal resting pressure was not different. During anal distention, the balloon expanded rapidly at an opening pressure of 49 (18) mm Hg, which was lower (P < .0001) than resting pressure (90 [25] mm Hg). The resting pressure was correlated with the opening pressure (r = 0.57, P < .0001) and inversely (r = -0.38, P = .007) with maximum volume but not with anal distensibility (volume-pressure slope). In healthy women, the difference (opening-resting pressure) was correlated with anal relaxation during evacuation (r = 0.35, P = .04). Anal distensibility and sensory thresholds were not different between constipated and healthy women.

CONCLUSIONS

Among healthy and constipated women, a greater anal resting pressure is correlated with greater opening pressure and lower maximum volume during distention, and, hence, provides a surrogate marker of anal distensibility. The difference (opening-resting pressure), which reflects anal relaxation during distention, is correlated with anal relaxation during evacuation. Anal resting pressure and distensibility were comparable in healthy and constipated women.

Constipation in 44 patients implanted with an artificial bowel sphincter

PURPOSE

Constipation with or without obstructed defecation (OD) is frequent in patients with artificial bowel sphincter (ABS). The aims of this study were (1) to evaluate the functional outcome of ABS based on postoperative constipation and (2) to assess pre-implantation data to predict post-implantation constipation.

MATERIALS AND METHODS

Thirteen men and 31 women were followed up. Both fecal incontinence and constipation with and without OD were assessed after implantation. Pre-implantation characteristics were compared in patients with and without postoperative constipation.

RESULTS

After implantation, nine patients (20.4%) had constipation without OD, 16 patients (36.4%) had OD, and 19 patients (43.2%) had neither of these. Incontinence was significantly more frequent in patients with postoperative constipation with or without OD. In these patients, an increase in preoperative constipation, anismus, and ultraslow waves was noted.

CONCLUSION

Constipation with and without OD is frequent after implantation and interfere with the functional outcome of ABS.

[Role of defecography in female posterior pelvic floor abnormalities]

Pelvic floor abnormalities often impact significantly the quality of life and result in a variety of symptoms, including chronic pelvic pain, fecal incontinence, and obstructed constipation. Fluoroscopic defecography and MR defecography enable identification of rectocele, rectal prolapse, enterocele, sigmoidocele with high prevalence in female patients with obstructed constipation, fecal incontinence, and chronic pelvic pain. In this manuscript, we describe the techniques and indications of the two techniques of defecography. We discuss the abnormalities of the posterior pelvic floor compartment at the origin of constipation, incontinence, chronic pelvic pain. Finally we compare the data obtained by clinical examination and defecography, remembering that 50% of enterocele and 100% of sigmoidocele are missed at clinical examination.

Anal ultraslow waves and high anal pressure in childhood: a clinical condition mimicking Hirschsprung disease

PURPOSE

Anal ultraslow waves (USWs) have been described in several clinical conditions closely related to chronic constipation associated with high anal pressure; however, USW-related clinical manifestations in childhood are poorly understood. The purpose of this study is to elucidate the clinical relevance of USWs in childhood.

METHODS

Manometric recordings of 118 cases including 70 children with constipation and 16 patients with Hirschsprung disease were analyzed.

RESULTS

Ultraslow waves were seen in 4 of 70 children with constipation. None of the controls or patients with Hirschsprung disease exhibited USWs. The 4 patients comprised 2 infants with marked abdominal distension mimicking Hirschsprung disease and 2 children (aged 4 and 8 years) with intractable constipation accompanying hemorrhoid or anal fissure. The manometric findings of the USW-positive patients showed a markedly high anal resting pressure and high frequency of slow waves compared to controls, patients with constipation not accompanied by USWs or patients with Hirschsprung disease.

CONCLUSION

Children with USWs exhibit symptoms mimicking Hirschsprung disease in infants and chronic intractable constipation in older children. In manometric studies of children, more attention should be paid not only to rectoanal reflex, but also USWs.

Multiple clinical presentations of anal ultra slow waves and high anal pressure: megacolon, hemorrhoids and constipation

The physiopathology of idiopathic chronic constipation is complex and yet to be investigated. In the manometric studies of the patients with severe chronic constipation, we noticed that some patients with megacolon show very slow periodical (< 2/min) pressure change in the anal canal, namely ultra slow waves (USWs). USWs are considered to represent the hyperactivity of the internal anal sphincter; however, USW-related clinical presentations have yet to be investigated. We retrospectively re-evaluated the patient records and manometric studies of 85 cases, 51 subjects without defecatory problems and 34 patients with constipation, to elucidate USW-related clinical presentations. USWs were seen in 10 patients, including eight patients with chronic constipation and two subjects without defecatory problems. Out of the eight patients with constipation, one had no organic change in the anorectum, three had hemorrhoids and four exhibited megacolon. Manometric and pathological studies proved that none of the four patients with megacolon was suffering from Hirschsprung's disease. Among the 51 subjects without defecatory problems, only two had USWs. Anal pressure in the USW-positive group (106.0 +/- 37.0 cmH2O) was significantly higher than that in the group without defecatory problems (56.0 +/- 27.0 cmH2O) or constipated patients without USWs (55.0 +/- 26.0 cmH2O). Megacolon and high anal pressure, as well as chronic constipation and hemorrhoids, were the clinical presentations related to USWs. This is the first report to show the clinical relevance of USWs to megacolon. USWs should be recognized as an important manometric finding indicating a possible new clinical entity in chronic constipation.

Surgical versus chemical (botulinum toxin) sphincterotomy for chronic anal fissure: long-term results of a prospective randomized clinical and manometric study

BACKGROUND

The aim of this prospective randomized trial was to compare the effectiveness and morbidity of surgical versus chemical sphincterotomy in the treatment of chronic anal fissure after a 3-year follow-up.

METHODS

Eighty patients with chronic anal fissure were treated by whether open lateral internal sphincterotomy (group 1) or chemical sphincterotomy with 25 U botulinum toxin injected into the internal sphincter (group 2). Clinical and manometric results were analyzed.

RESULTS

Overall healing was 92.5% in the open sphincterotomy group and 45% in the toxin botulinum group (P<.001). There is a group of patients with clinical (duration of disease >12 months and presence of a sentinel pile before treatment) and manometric factors (persistently elevated mean resting pressure, % of time presence of slow waves, and number of patients or the time presence ultra slow waves after treatment) associated with a higher recurrence of anal fissure. The final percentage of incontinence was 5% in the open sphincterotomy group and 0% in the botulinum toxin group (P>.05).

CONCLUSION

We recommend surgical sphincterotomy as the first therapeutic approach in patients with clinical and manometric factors of recurrence. We prefer the use of botulinum toxin in patients older than 50 years or with risk factors for incontinence, despite the higher rate of recurrence, since it avoids the greater risk of incontinence in the surgical group.

Long-term results of botulinum toxin for the treatment of chronic anal fissure: prospective clinical and manometric study

BACKGROUND

The aim of this prospective trial was to analyse the effectiveness and morbidity of chemical sphincterotomy in the treatment of chronic anal fissure after a 3-year follow-up.

METHODS

One hundred consecutive patients with chronic anal fissures were treated by chemical sphincterotomy with 25 U botulinum toxin injected into the internal sphincter. Clinical and manometric results were recorded.

RESULTS

No major complications were found; initial incontinence at the 2-month review (6%) spontaneously reversed at 6 months. There was a tendency of progressive recurrence over time, with an overall healing after 3 years of 47%. We found a group of patients with clinical (symptoms longer than 12 months and presence of a sentinel pile before treatment) and manometric factors (persistently elevated mean resting pressure, percentage of time with slow waves, and number of patients or percentage of time with ultra slow waves after treatment) associated with a higher recurrence of anal fissures.

CONCLUSION

Since it avoids the greater risk of incontinence associated with surgical sphincterotomy, we recommend the use of botulinum toxin as the first therapeutic approach for patients with chronic anal fissure and risk factors for incontinence; despite the higher rate of recurrence associated with this treatment. In patients with factors related to recurrence, re-injection with higher doses of botulinum toxin or complementary medical-surgical treatment should be considered.

Effect of continuous rectal distention on anal resting pressure

PURPOSE

Intermittent distention of the rectum induces internal anal sphincter relaxation, but whether continuous rectal distention might affect the resting pressure of the anal canal and the frequency of internal anal sphincter relaxations has not yet been investigated. The aim of this study was to record anal pressure under resting conditions and at two levels of continuous rectal distention.

METHODS

Anal pressure was recorded by means of water-perfused catheters under resting conditions and at two levels of rectal distention controlled by an electronic barostat in eight healthy subjects.

RESULTS

Continuous rectal distention did not significantly change mean anal resting pressure, but it did significantly decrease the amplitude of ultraslow waves (from 29 +/- 9 mmHg under resting conditions to 23 +/- 6 and 21 +/- 3 mmHg during lesser and greater rectal distention; P = 0.017 and P = 0.012, respectively) and increase the frequency of internal anal sphincter relaxations (from 1.3 +/- 1.3/hour under resting conditions to 8.8 +/- 4.3/hour and 11.0 +/- 4.8/hour during lesser and greater distention; P = 0.012 in both comparisons).

CONCLUSIONS

The resting pressure of the anal canal is maintained during continuous rectal distention. The decreased amplitude of ultraslow waves and increased frequency of the internal anal sphincter relaxations induced by rectal distention reveal a complex functional relationship between the rectum and the anal canal.

Double-blind manometric assessment of two topical glyceryl trinitrate formulations in patients with chronic anal fissures

BACKGROUND

Chronic anal fissure is a frequent and troubling condition, that may need surgical sphincterotomy for relief of symptoms. However, this approach may yield minor incontinence in up to 30% of cases. Interest has, therefore, recently increased in "chemical sphincterotomy" by using topical glyceryl trinitrate ointment. Unfortunately, there is, to date, no specific pharmaceutical preparation of such compound.

AIMS

To compare, according to a randomized double-blind crossover study, the effects of a pharmaceutical preparation of a specific 0.2% glyceryl trinitrate ointment (PMF 303) and of the common preparation reported in the literature on the anal resting pressure in patients with anal fissure.

PATIENTS AND METHODS

Twelve patients with chronic anal fissure (6 males and 6 females, age range 23-60 years] were recruited for the study. Two paired manometric studies were carried out at one-week intervals. After the basal anal pressure had been assessed, the patients were randomized to receive either one of the two preparations, and manometric measurements were repeated at 20, 40 and 60 minutes.

RESULTS

No differences were found between anal resting pressure in the basal study. Both preparations were able to significantly decrease (p=0.001) anal pressure throughout the study period. No significant differences were found between the two preparations.

CONCLUSIONS

PMF 303 is able to decrease anal pressure in patients with anal fissure, to a similar extent to the widely tested (galenic) literature preparation. Availability of a specific formulation for the treatment of this condition may be clinically useful.

Anal pressure waves in patients with irritable bowel syndrome

PURPOSE

Many data suggest in irritable bowel syndrome a generalized smooth-muscle disorder, but data are scant concerning anal waves in patients with irritable bowel syndrome. The aim of the present study was first to propose a new method of anal pressure-wave analysis and second to apply this method to patients with irritable bowel syndrome.

METHODS

Spectral analysis was used in 20 healthy controls and 60 patients with irritable bowel syndrome to investigate anal pressure waves at rest during a standard anorectal test and during a maintained 12-ml anal distention.

RESULTS

Adaptation of the anal canal to maintained distention was similar in the two groups of subjects. Using a cluster analysis, three groups of anal waves were defined (in cycles per minute): ultra slow waves (0.9-3.3), slow waves (3.8-16.4), and simple waves (16.9-23). In the resting state only simple waves were found less prevalent in patients with irritable bowel syndrome. During maintained distention, ultra slow waves increase in both groups, but slow waves increase in patients with irritable bowel syndrome and simple waves decrease in controls.

CONCLUSIONS

Characterization of anal pressure waves is a simple procedure that is easy to perform in outpatients. Anal pressure waves of patients with irritable bowel syndrome have altered organization and respond differently to distention as compared with controls.