Colonic and anorectal motility in young women with severe idiopathic constipation

Forty-four severely constipated women and 16 (8 female, 8 male) asymptomatic volunteers underwent assessment of colon function by (a) clinical examination, (b) rectosigmoid intraluminal pressure recording, (c) colonic transit utilizing radiopaque markers, (d) anorectal manometry, and (e) rectosigmoid electrical activity. Constipated patients were characterized by (a) a greater volume and pressure of rectal distention required for both sensation and sphincter relaxation, (b) diminished basal and postmorphine motility indices only in the distal rectum, (c) delayed transit, and (d) an empty rectum when severely constipated. A neural abnormality affecting afferent nerves may be present in the rectum of female patients with severe idiopathic constipation. Delivery of stool to the rectum is impaired in these patients.     

Impairment of defecation in young women with severe constipation

Anorectal manometry, radiology, and tests of simulated defecation were carried out in 14 severely constipated young women and 29 age-matched controls. The resting anal sphincter pressures were reduced in the patients, but the squeeze pressures, rectoanal inhibitory reflex, and rectal pressures upon balloon distention were all normal. At rest, the anorectal angle was more obtuse in the constipated group, but there was no overall increase in perineal descent in constipated patients compared with controls. The presence of a balloon in the rectum and the onset of pain were perceived in constipated patients at volumes that were not significantly different from those in normal volunteers. Constipated patients, however, required higher rectal volumes to induce the desire to defecate and to stimulate regular rectal contractions. Constipated patients also found it more difficult to pass simulated stools from the rectum than the normal controls and, unlike most normal controls, failed to inhibit their external anal sphincter on attempted defecation. These findings suggest that young women with severe constipation have great difficulty initiating the coordinated set of events that constitute a normal defecation response.     

Alpha1-Antitrypsin Deficiency May Be a Risk Factor for Duodenal Ulcer in Patients with Helicobacter pylori Infection

Background: It is not known whether evaluation of motor and sensory function of the rectum using a barostat may help to distinguish subtypes of constipation. Methods: Motor and sensory function of the rectum have been evaluated using a barostat in 14 patients with slow transit constipation (STC), 12 patients with constipation-predominant irritable bowel syndrome (IBS) and 18 healthy controls. First minimal distending pressure was determined, after which spontaneous adaptive relaxation of the rectum was monitored. Then a step-wise isobaric distension procedure was performed, during which symptom perception was determined. The distension was followed by a 90-min barostat procedure: for 30 min in the basal state followed by ingestion of a semi-liquid meal (postprandial state). Results: Minimal distending pressure was not different between both patient groups and controls, neither was compliance different between constipated patients and controls. The degree of spontaneous adaptive relaxation was in the same range in all groups. During distensions with high pressures, the perception of urge was significantly reduced in STC patients compared to IBS and controls, while the perception of pain was significantly increased in IBS versus STC and controls. Postprandially, a small decrease of rectal volume was only observed in the control group, but not in the patients. Conclusions: Rectal motor characteristics are not different between patients with constipation-predominant IBS, patients with STC and healthy controls while during isobaric distensions, sensations of urge were reduced in STC and sensations of pain were increased in IBS. Rectal visceroperception testing may help distinguish groups of patients with different subtypes of constipation.     

Abnormal rectoanal function in children recovered from chronic constipation and encopresis

It is unknown if abnormal anal sphincter function as assessed by anorectal manometry is still present years after resolution of chronic constipation and encopresis. Twenty healthy controls, 12 children with constipation but no encopresis, and 20 children with chronic constipation and encopresis underwent anorectal manometric testing, using intraluminal pressure transducers and a balloon for rectal distention. Anorectal measurements were repeated in the 20 constipated and encopretic children 2.5-4 yr after treatment began; 11 children had recovered for at least 1 yr. The mean values of anal resting tone and of anal pull-through pressure were lower in the constipated and encopretic children than in the 20 control children (p less than 0.003). Percent relaxation of the rectosphincteric reflex after rectal distention of 30 and 60 ml was lower in constipated children with and without encopresis than in controls (p less than 0.003), whereas the means of rectosphincteric reflex threshold were comparable in the three groups of children. Three years after initiation of treatment with milk of magnesia, high-fiber diet, and bowel training techniques, the mean values of anal resting tone, anal pull-through pressure, and percent relaxation of rectosphincteric reflex remained significantly lower in both recovered and nonrecovered constipated and encopretic patients compared with controls. It was suggested that the underlying cause of chronic constipation is the decreased ability of the internal anal sphincter to relax with rectal distention, and the hypotonia of the anal canal is responsible for the encopresis. Abnormal anorectal functions were still present years after cessation of treatment and recovery and put the recovered patient at risk for recurrence of chronic constipation and encopresis.     

Study on functional constipation and constipation‐predominant irritable bowel syndrome by using the colonic transit test and anorectal manometry

OBJECTIVE: To investigate the visceral perception, anorectal pressure and colonic transit time (CTT) in patients with functional constipation and constipation‐predominant irritable bowel syndrome (C‐IBS), and to study the manometric abnormalities of these two conditions. METHODS: The CTT in patients with functional constipation and C‐IBS was studied by using radiopaque markers. Rectal visceral perception thresholds, rectal compliance and anorectal pressure were examined by electric barostat. RESULTS: The CTT in both groups of constipated patients was abnormal. A lot of radiopaque markers remained in the right colon in C‐IBS patients, whereas in patients with functional constipation, the radiopaque markers remained in each segment of the colon. The anorectal resting pressure, squeezing pressure and relaxation pressure were normal in both groups. Rectal compliance and defecation thresholds were much higher compared with controls, and the rectal visceral perception of functional constipation was also abnormal. CONCLUSIONS: The motility abnormalities of functional constipation and C‐IBS occurred in different colonic segments. Results suggest that CTT measure­ment and anorectal manometry could be helpful in the differential diagnosis of these two conditions.     

Motor and sensory function of the rectum in different subtypes of constipation

BACKGROUND: It is not known whether evaluation of motor and sensory function of the rectum using a barostat may help to distinguish subtypes of constipation. METHODS: Motor and sensory function of the rectum have been evaluated using a barostat in 14 patients with slow transit constipation (STC), 12 patients with constipation-predominant irritable bowel syndrome (IBS) and 18 healthy controls. First minimal distending pressure was determined, after which spontaneous adaptive relaxation of the rectum was monitored. Then a step-wise isobaric distension procedure was performed, during which symptom perception was determined. The distension was followed by a 90-min barostat procedure: for 30 min in the basal state followed by ingestion of a semi-liquid meal (postprandial state). RESULTS: Minimal distending pressure was not different between both patient groups and controls, neither was compliance different between constipated patients and controls. The degree of spontaneous adaptive relaxation was in the same range in all groups. During distensions with high pressures, the perception of urge was significantly reduced in STC patients compared to IBS and controls, while the perception of pain was significantly increased in IBS versus STC and controls. Postprandially, a small decrease of rectal volume was only observed in the control group, but not in the patients. CONCLUSIONS: Rectal motor characteristics are not different between patients with constipation-predominant IBS, patients with STC and healthy controls while during isobaric distensions, sensations of urge were reduced in STC and sensations of pain were increased in IBS. Rectal visceroperception testing may help distinguish groups of patients with different subtypes of constipation.     

Anorectal manometry in patients with chronic constipation: a single-center experience

BACKGROUND/AIMS: Constipation is a common complaint, but its clinical presentation varies with each individual. The aim of this study was to evaluate anorectal physiology in a prospective group of patients with chronic constipation. METHODOLOGY: A total of 24 consecutive patients with constipation underwent solid-state anorectal manometry. Fifteen healthy controls were also studied. The anorectal parameters included resting and squeeze sphincter pressure, sensory thresholds in response to balloon distension, compliance of rectum, and rectoanal inhibitory reflex (RAIR). RESULTS: The rectal sensitivity for urge and pain did not differ between the groups, but the threshold volume for first sensation was higher in patients with constipation (p < 0.05). There was no group difference in the volume threshold for RAIR. However, the prevalence of impaired RAIR was higher in constipated patients. Anal pressure was lower in patients for maximal squeeze (p < 0.05). There was a positive correlation between the anal sphincter length and resting pressure in patients (r = 0.51, p = 0.03) and healthy controls (r = 0.72, p = 0.01). CONCLUSIONS: Constipated patients are characterized by impaired rectal sensitivity and decreased anal sphincter contractile pressure. Anorectal manometry is helpful for diagnosing anorectal dysfunction in patients with chronic constipation.     

Rectal compliance in females with obstructed defecation

PURPOSE: This study was designed to investigate whether rectal compliance is altered in females with obstructed defecation. METHODS: Eighty female patients with obstructed defecation and 60 control subjects were studied. Rectal compliance was measured with an infinitely compliant polyethylene bag. This bag was inserted in the rectum and inflated with air to selected pressure plateaus (range, 0–60 mmHg; cumulative steps of 2 mmHg with a duration of ten seconds) using a computer-controlled electromechanical barostat system. Volume changes at the levels of distending pressures were recorded. The distending pressures, needed to evoke first sensation of content in the rectum, earliest urge to defecate, and the maximum tolerable volume were noted. RESULTS: In all cases, the compliance curve had a characteristic triphasic (S-shaped) form. The mean compliance curve obtained from the patients was identical to that of the controls. However, the course of the compliance curve fell above the normal range (mean + 2 SD) in 14 patients. In ten (71 percent) of these patients, a large rectocele was seen at evacuation proctography. Such a rectocele was observed in only five patients (7.6 percent) with a normal compliance curve (P<0.001). Eighty percent of the controls experienced earliest urge to defecate during the second phase of the curve. In 75 percent of the patients, this occurred in the third phase. The mean pressure threshold for first sensation, earliest urge to defecate, and maximum tolerable volume were significantly higher in patients compared with control subjects. Ten of the patients experienced no sensation at all in the pressure range between 0 and 60 mmHg. CONCLUSION: In females with obstructed defection, the compliance of the rectal wall is normal.     

Radiologic studies of rectal evacuation in adults with idiopathic constipation

A consecutive series of 58 patients with idiopathic constipation and 20 control subjects were studied by evacuation proctography and measurements were made of changes during rectal expulsion. A wide range was found in the control group. The anorectal angle, pelvic floor descent, and the presence or size of an anterior rectocele did not discriminate between the control and patient groups. Internal intussusception was rare. Among constipated patients, the only significant differences from normal were in the time taken to expel barium and the amount of barium remaining in the distal rectum. The majority of control subjects (15 of 20) evacuated most of the barium within 20 seconds whereas 45 of 58 constipated patients took a longer time. Using the area of barium on a lateral view of the rectum as a measure, 19 of 20 control subjects evacuated at least 60 percent of the barium from the distal 4 cm of the rectum compared with only 25 of 58 patients. A varying degree of defecatory impairment was thus established among many patients with constipation. The patients were subdivided into those with a normal or abnormal whole gut transit rate as an indication of colonic function, and those who did or did not need to digitally evacuate the rectum as a clinical manifestation of an anorectal disorder. No obvious differences were found between these subgroups using the parameters measured.     

慢性特发性便秘患者肛门直肠测压表现及西沙必利的疗效研究

目的研究慢性特发性便秘（CIC）患者肛门直肠动力及直肠对容量刺激感觉的变化，同时观察西沙必利对CIC的疗效及对上述指标的影响。方法用肛门直肠测压法检测30例CIC患者，服用西沙必利前后的直肠动力及直肠对容量刺激感觉的变化。20名健康者作对照。结果肛门直肠括约肌最大收缩压降低（P＜0．05），引起直肠肛门抑制性反射的最小松弛容量（MRV）增大（P＜0．05），直肠内部容量刺激的排便阈值及疼痛阈值均明显增加（P＜0．01）；西沙必利10mg每日3次治疗4周可显著改善CIC患者上述异常改变（P＜0．01），增加CIC患者排便次数（P＜0．01），治疗总有效率为46，67％。结论CIC患者存在肛门直肠动力及内脏感觉异常，西沙必利可改善上述异常表现，对约半数CIC患者具有良好疗效。     

Contributions of evacuation proctography and anorectal manometry to evaluation of adults with constipation and defecatory difficulty

We prospectively evaluated 36 patients who complained of chronic constipation and/or defecatory difficulties to determine the role of anorectal manometry and evacuation proctography in delineating the pathogenesis of these complaints. Twenty patients with constipation also underwent a colonic transit study with radioopaque markers, which identificd one group with normal transit (N=10) and another with slow transit (N=10). Nine of 36 patients (25%) had inappropriate puborectalis muscle contraction or exhibited weak expulsion efforts during evacuation proctography, and these correlated highly with poor rectal emptying of barium paste (20±6% vs 61±5% in patients with normal relaxation; P<0.01). However, poor rectal emptying did not correlate with the presence of high-grade intussusceptions, large rectoceles, anorectal angles at rest or with straining, rectal diameter, clinical features, or colonic transit. Moreover, abnormal expulsion patterns as seen with anorectal manometry correlated poorly with the presence of inappropriate puborectalis contraction and decreased rectal emptying by proctography. Although anatomic abnormalities occurred frequently in patients with constipation and/or defecatory difficulties, they were also prevalent in asymptomatic controls. In view of these findings, surgical intervention to correct anatomic abnormalities in patients with constipation and/or defecatory difficulties should be considered only with great caution.     

Rectoanal reflex parameters in incontinence and constipation

PURPOSE: The transient relaxation of the internal anal sphincter in response to rectal distention is believed to play an important role in the continence mechanism. Most anorectal physiology laboratories merely report the rectoanal inhibitory reflex as being either present or absent. This study aimed to assess the parameters of the rectoanal inhibitory reflex in incontinent and constipated patients and healthy control subjects, in an attempt to analyze differences in internal anal sphincter function in these groups. We analyzed each response of the internal anal sphincter to rectal distention with progressively increasing volumes of air at a single site (proximal anal canal). METHODS: Fifty-five constipated and 99 incontinent patients and healthy control subjects underwent manometry. Various parameters of the rectoanal inhibitory reflex were analyzed, and percentage sphincter relaxation was calculated at each volume at which rectoanal inhibitory reflex occurred. RESULTS: There was no difference in the volume of rectal distention required to elicit sensation (P = 0.626) or the rectoanal inhibitory reflex (P = 0.371) in the three groups. There was a significant correlation between the volume required to elicit the rectoanal inhibitory reflex and that at which sensation was first felt only in the incontinent (P = 0.0001) group. Significantly greater sphincter relaxation was seen at each volume (P = 0.001) in the incontinent as compared with the constipated patients. With progressive rectoanal inhibitory reflex, consistently progressive increases in internal anal sphincter relaxation were found only in the incontinent group. This consistent relationship was not seen in the constipated patients or in healthy control subjects. CONCLUSIONS: Assessment of various parameters of the rectoanal inhibitory reflex yielded important information regarding the continence mechanism. Altered responses of the internal anal sphincter in anorectal disorders plays a role in the associated physiologic impairment. This may have significant clinical implications with regard to sphincter-saving resections.     

Idiopathic megarectum in adults

Outlet obstruction is thought to be one of the major factors responsible for idiopathic constipation. However, outlet obstruction itself may be due to several mechanisms. Among these, the presence of a megarectum is a leading one. Pathophysiological studies in adult patients with idiopathic megarectum are scarce. We studied by manometric and defecographic means 15 adult subjects with idiopathic megarectum and severe chronic constipation. Twenty-five healthy volunteers of both sexes acted as controls. Manometric variables showed significant differences between patients and controls with respect to internal anal sphincter pressure (P=0.02), minimum relaxation volume (P<0.001), defecatory sensory threshold (P<0.001), mean rectal tolerable volume (P<0.001), and rectal compliance (P<0.001). An altered response to straining was observed in 46.6% of patients and in 12% of controls (P=0.04); the ability to expel a 50-ml balloon per anum was 13.3% in patients and 100% in controls (P<0.001). Although all patients opened the anorectal angle and had descent of the pelvic floor, thereby confirming an adequate expulsion effort, evacuation of contrast material appeared extremely difficult. In fact, no subject was able to expel more than 30% of the rectal contents during fluoroscopic screening. These results confirm previous hypotheses that idiopathic megarectum displays features of a neuropathic process as an underlying mechanism. Further studies are needed that also take into consideration the muscle tone component of the rectum in these patients.     

Constipation of anorectal outlet obstruction: pathophysiology, evaluation and management

Constipation is a subjective symptom of various pathological conditions. Incidence of constipation fluctuates from 2 to 30% in the general population. Approximately 50% of constipated patients referred to tertiary care centers have obstructed defecation constipation. Constipation of obstructed defecation may be due to mechanical causes or functional disorders of the anorectal region. Mechanical causes are related to morphological abnormalities of the anorectum (megarectum, rectal prolapse, rectocele, enterocele, neoplasms, stenosis). Functional disorders are associated with neurological disorders and dysfunction of the pelvic floor muscles or anorectal muscles (anismus, descending perineum syndrome, Hirschsprung's disease). However, this type of constipation should be differentiated by colonic slow transit constipation which, if coexists, should be managed to a second time. Assessment of patients with severe constipation includes a good history, physical examination and specialized investigations (colonic transit time, anorectal manometry, rectal balloon expulsion test, defecography, electromyography), which contribute to the diagnosis and the differential diagnosis of the cause of the obstructed defecation. Thereby, constipated patients can be given appropriate treatment for their problem, which may be conservative (bulk agents, high-fiber diet or laxatives), biofeedback training or surgery.     

Rectal compliance as a routine measurement

PURPOSE: The clinical impact of rectal compliance and sensitivity measurement is not clear. The aim of this study was to measure the rectal compliance in different patient groups compared with controls and to establish the clinical effect of rectal compliance. METHODS: Anorectal function tests were performed in 974 consecutive patients (284 men). Normal values were obtained from 24 controls. Rectal compliance measurement was performed by filling a latex rectal balloon with water at a rate of 60 ml per minute. Volume and intraballoon pressure were measured. Volume and pressure at three sensitivity thresholds were recorded for analysis: first sensation, urge, and maximal toleration. At maximal toleration, the rectal compliance (volume/pressure) was calculated. Proctoscopy, anal manometry, anal mucosal sensitivity, and anal endosonography were also performed as part of our anorectal function tests. RESULTS: No effect of age or gender was observed in either controls or patients. Patients with fecal incontinence had a higher volume at first sensation and a higher pressure at maximal toleration (P=0.03), the presence of a sphincter defect or low or normal anal pressures made no difference. Patients with constipation had a larger volume at first sensation and urge (P<0.0001 andP<0.01). Patients with a rectocele had a larger volume at first sensation (P=0.004). Patients with rectal prolapse did not differ from controls; after rectopexy, rectal compliance decreased (P<0.0003). Patients with inflammatory bowel disease had a lower rectal compliance, most pronounced in active proctitis (P=0.003). Patients with ileoanal pouches also had a lower compliance (P<0.0001). In the 17 patients where a maximal toleration volume<60 ml was found, 11 had complaints of fecal incontinence, and 6 had a stoma. In 31 patients a maximal toleration volume between 60 and 100 ml was found; 12 patients had complaints of fecal incontinence, and 6 had a stoma. Proctitis or pouchitis was the main cause for a small compliance. All 29 patients who had a maximal toleration volume>500 ml had complaints of constipation. No correlation between rectal and anal mucosal sensitivity was found. CONCLUSION: Rectal compliance measurement with a latex balloon is easily feasible. In this series of 974 patients, some patient groups showed an abnormal rectal visceral sensitivity and compliance, but there was an overlap with controls. Rectal compliance measurement gave a good clinical impression about the contribution of the rectum to the anorectal problem. Patients with proctitis and pouchitis had the smallest rectal compliance. A maximal toleration volume<60 ml always led to fecal incontinence, and stomas should be considered for such patients. A maximal toleration volume>500 ml was only seen in constipated patients, and therapy should be given to prevent further damage to the pelvic floor. Values close to or within the normal range rule out the rectum as an important factor in the anorectal problem of the patient.Drs. Sloots and Poen were supported by a grant from Janssen-Cilag. Presented at the meeting of the Dutch Society of Gastroenterology, Veldhoven, the Netherlands, October 7 to 8, 1999.     

Manometric assessment of idiopathic megarectum in constipated children

AIM: Chronic constipation is a frequent finding in children. In this age range, the concomitant occurrence of megarectum is not uncommon. However, the definition of megarectum is variable, and a few data exist for Italy. We studied anorectal manometric variables and sensation in a group of constipated children with megarectum defined by radiologic criteria. Data from this group were compared with those obtained in a similar group of children with recurrent abdominal pain. METHODS: Anorectal testing was carried out in both groups by standard manometric technique and rectal balloon expulsion test. RESULTS: Megarectum patients displayed discrete abnormalities of anorectal variables and sensation with respect to controls. In particular, the pelvic floor function appeared to be impaired in most patients. CONCLUSION: Constipated children with megarectum have abnormal anorectal function and sensation. These findings may be helpful for a better understanding of the pathophysiological basis of this condition.     

Rectopexy is an ineffective treatment for obstructed defecation

The symptoms of obstructed defecation have been attributed to rectal intussusception, and thus rectopexy has been advocated in the surgical management. In this study, patients with obstructed defecation underwent manometry and proctography before and after rectopexy. Seventeen patients (16 females and one male, mean age 51.6 years) were studied. Eleven underwent anterior and posterior fixation of the rectum and six had posterior fixation only. Preoperatively five patients demonstrated rectoanal intussusceptions. Fifteen had significant pelvic descent. No significant change in maximum resting pressure, maximum voluntary contraction, pelvic descent, or anorectal angle was seen postoperatively. In the initial follow-up, many patients had significant amelioration of symptoms. However, on longer follow-up (mean 30.8 months) only two had long-term improvement. The remainder had a poor clinical result in spite of complete resolution of rectal intussusception. Many reported a worsening of symptoms as reflected by an increase in tenesmus and stool frequency. In the two cases with a satisfactory result, both could empty the rectum completely and demonstrated rectoanal intussusception on preoperative evacuation proctography. In those with poor results, four had complete emptying and three had rectoanal intussusception. In conclusion rectopexy is an ineffective treatment for obstructive defecation in most patients.Read at the Tripartite Meeting, Birmingham, United Kingdom, June 19 to 22, 1989.Work is attributed to the Bristol Royal Infirmary, Bristol, United Kingdom.     

Sensory and motor responses to rectal distention vary according to rate and pattern of balloon inflation

Anorectal motor activity and rectal sensation were recorded in 12 normal male subjects during ramp distention of the rectum with water and air at randomized rates of 10, 20, 50, and 100 mL/min and during intermittent rapid distention with air. There were no significant differences between the results of ramp inflation with water or with air, and the repeated infusion of the same medium yielded reproducible results. Ramp distention induced sigmoid pressure-volume profiles. Different sensations occurred at specific points on the pressure-volume curve and were maintained until succeeded by the next sensation. Initial perception of the distention occurred during the initial steep pressure increase, the sensation of wind occurred during the plateau phase, and the desire to defecate occurred at the onset of the final rapid ascent. Rectal sensations were induced at lower volumes at low infusion rates when the slope of the pressure-volume relationship was shallower than at high infusion rates. This suggests that the receptor triggering rectal sensation is not a simple volume or pressure receptor, but is more likely to be a slowly adapting mechanoreceptor lying parallel to the circular muscle of the rectal wall. During rapid intermittent distention, the rectal volumes required to elicit rectal sensations were lower than during ramp distention, although the pressure-volume curve was steeper. Moreover, sensations often only lasted a short period of time but recurred on deflation. These data suggest activation of an additional population of rapidly adapting or high threshold mechanoreceptors. Anal relaxation was always evoked by intermittent rectal distention and was almost always associated with a rectal sensation and an increase in external anal sphincter activity. In contrast, anal relaxation could be absent or delayed during ramp inflation, especially at lower infusion rates, suggesting that internal sphincter can maintain continence for a long period of time while the rectum is slowly filling. Rectal sensation and concomitant external anal sphincter activity was not associated with anal relaxation during ramp inflation; most subjects felt the sensation long after the pressure reached its lowest level. However, under all circumstances the onset of rectal sensation was associated with an increase of external anal sphincter electrical activity. In conclusion, the rectal sensory and anorectal motor responses to distention depend on the rate and pattern of distention, which may activate a different population of receptors. Results from different laboratories cannot be compared directly unless the pattern and rate of distension are the same.     

Biofeedback Therapy for Fecal Incontinence

Operant conditioning offers a new therapeutic modality for fecal incontinence. Our experience with biofeedback therapy in six male and six female patients (ages 12–78 years) is presented. Incontinence was associated with a surgical procedure in six patients and with a medical condition in six patients. Rectosphincteric manometry was performed using a three balloon technic. with one balloon positioned in the rectum as a distending stimulus and the others at the internal and external sphincters. Pressure responses to measured volumes of rectal distention were displayed on a polygraph. Rectosphincteric reflexes and sensory thresholds for rectal distention were determined. Patients were then encouraged to elevate sphincter pressures while observing their manometric responses. Follow-up of 10–96 weeks showed ten patients had good responses, with complete continence in six patients. Nine of 10 responders required only one treatment session. Operant conditioning is a valuable technic in properly selected patients with an 80% probability of success.     

Rectal sensory perception in females with obstructed defecation

PURPOSE: Parasympathetic afferent nerves are thought to mediate rectal filling sensations. The role of sympathetic afferent nerves in the mediation of these sensations is unclear. Sympathetic nerves have been reported to mediate nonspecific sensations in the pelvis or lower abdomen in patients with blocked parasympathetic afferent supply. It has been reported that the parasympathetic afferent nerves are stimulated by both slow ramp (cumulative) and fast phasic (intermittent) distention of the rectum, whereas the sympathetic afferent nerves are only stimulated by fast phasic distention. Therefore, it might be useful to use the two distention protocols to differentiate between a parasympathetic and sympathetic afferent deficit. METHODS: Sixty control subjects (9 males; median age, 48 (range, 20–70) years) and 100 female patients (median age, 50 (range, 18–75) years) with obstructed defecation entered the study. Rectal sensory perception was assessed with an infinitely compliant polyethylene bag and a computer-controlled air-injection system. This bag was inserted into the rectum and inflated with air to selected pressure levels according to two different distention protocols (fast phasic and slow ramp). The distending pressures needed to evoke rectal filling sensations, first sensation of content in the rectum, and earliest urge to defecate were noted, as was the maximum tolerable volume. RESULTS: In all control subjects, rectal filling sensations could be evoked. Twenty-one patients (21 percent) experienced no sensation at all in the pressure range between 0 and 65 mmHg during either slow ramp or fast phasic distention. The pressure thresholds for first sensation, earliest urge to defecate, and maximum tolerable volume were significantly higher in patients with obstructed defecation (P<0.001). In each subject, the pressure thresholds for first sensation, earliest urge to defecate, and maximum tolerable volume were always the same, regardless of the type of distention. CONCLUSION: Rectal sensory perception is blunted or absent in the majority of patients with obstructed defecation. The observation that this abnormality can be detected by both distention protocols suggests that the parasympathetic afferent nerves are deficient. Because none of the patients experienced a nonspecific sensation in the pelvis or lower abdomen during fast phasic distention, it might be suggested that the sympathetic afferents are also deficient. This finding implies that it is not worthwhile to use different distention protocols in patients with obstructed defecation.