Anorectal sensitivity in patients with obstructed defaecation

Rectal hyposensitivity and functional anorectal outlet obstruction are common entities in patients with functional constipation but are not significantly associated

BACKGROUND/AIMS

The causes of functional anorectal outlet obstruction (outlet obstruction) include functional defecation disorder (FDD), rectocele, and rectal intussusception (RI). It is unclear whether outlet obstruction is associated with rectal hyposensitivity (RH) in patients with functional constipation (FC). The aim of this study was to determine the association between RH and outlet obstruction in patients with FC.

METHODS

This was a retrospective study using a prospectively collected constipation database, and the population comprised 107 patients with FC (100 females; median age, 49 years). We performed anorectal manometry, defecography, rectal barostat, and at least two tests (balloon expulsion test, electromyography, or colon transit time study). RH was defined as one or more sensory threshold pressures raised beyond the normal range on rectal barostat. We investigated the association between the presence of RH and an outlet obstruction such as large rectocele (> 2 cm in size), RI, or FDD.

RESULTS

Forty patients (37.4%) had RH. No significant difference was observed in RH between patients with small and large rectoceles (22 [44.9%] vs. 18 [31%], respectively; p = 0.140). No significant difference was observed in RH between the non-RI and RI groups (36 [36.7%] vs. 4 [30.8%], respectively; p = 0.599). Furthermore, no significant difference in RH was observed between the non-FDD and FDD groups (19 [35.8%] vs. 21 [38.9%], respectively; p = 0.745).

CONCLUSIONS

RH and outlet obstruction are common entities but appear not to be significantly associated.

Rectal hyposensitivity is uncommon and unlikely to be the central cause of obstructed defecation in patients with high-grade internal rectal prolapse

BACKGROUND

There are several causes of obstructed defecation one of which is thought to be internal rectal prolapse. Operations directed at internal prolapse, such as laparoscopic ventral rectopexy, may improve obstructed defecation symptoms significantly. It is not clear whether the obstructed defecation with internal prolapse is a mechanical phenomenon or whether it results changes in rectal sensitivity. This study aimed to evaluate rectal sensory function in patients with obstructed defecation and high-grade internal rectal prolapse.

METHODS

This study represents a retrospective review of a prospectively collected database of patients attending a tertiary referral pelvic floor unit. Patients with high-grade (recto-anal) intussusception formed the basis of this study. Rectal sensory function was determined by intrarectal balloon inflation. Three parameters (sensory threshold, urge to defecate and maximum tolerated volumes) were recorded. Abnormal sensitivity was defined as partial (one or two parameters abnormal) or total (all three abnormal).

KEY RESULTS

Four hundred and eight patients with high-grade internal rectal prolapse both with and without obstructed defecation symptoms were studied. Two hundred and forty one (59%) had normal sensation. Eighteen (4%) had total hyposensitivity and three (1%) total hypersensitivity. A further 96 (24%) had partial hyposensitivity whilst 50 (12%) had partial hypersensitivity. Neither hypersensitivity nor hyposensitivity differed between patients with and without symptoms of obstructed defecation.

CONCLUSIONS & INFERENCES

Rectal hyposensitivity is relatively uncommon in patients with high-grade internal rectal prolapse and obstructed defecation. Internal rectal prolapse may cause obstructed defecation through a mechanical process. It does not appear that rectal hyposensitivity plays a significant part in the pathological process.

Impaired proximal colonic motor response to rectal mechanical and chemical stimulation in obstructed defecation

PURPOSE

Both motor and sensory dysfunction have been implicated in the pathogenesis of obstructed defecation. We have found that despite preservation of a defecatory urge, patients with obstructed defecation have lost the normal predefecatory augmentation in frequency and amplitude of colonic propagating pressure waves. This observation might be explainable by either altered rectal sensory thresholds or by dysfunction in the colonic motor apparatus. By measuring rectal sensory thresholds and proximal colonic motor responses to rectal mechanical and chemical stimuli, we tested the hypotheses that central perception of rectal stimuli is enhanced and that the proximal colonic motor response to rectal stimulation is attenuated.

METHODS

In seven patients with obstructed defecation and ten healthy volunteers we measured proximal colonic motor responses and sensory thresholds in response to both rectal balloon distention and rectal instillation of chenodeoxycholic acid.

RESULTS

In controls, but not in patients, rectal mechanical distention significantly reduced and chemical stimulation significantly increased the frequency of proximal colonic propagating sequences (P = 0.01). There was no significant difference in rectal sensory thresholds between patients and controls. Prior instillation of chenodeoxycholic acid significantly reduced (P < 0.03) maximum tolerated balloon volume and defecatory urge volume to comparable degree in both patients and controls.

CONCLUSIONS

In obstructed defecation, 1) the normal rectocolonic pathways mediating stimulation-induced proximal colonic propagating pressure waves are nonfunctioning, and. 2) central perception of these rectal stimuli is normal.

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.

Prognostic significance of rectocele, intussusception, and abnormal perineal descent in biofeedback treatment for constipated patients with paradoxical puborectalis contraction

PURPOSE

The findings of paradoxical puborectalis contraction, rectocele, sigmoidocele, intussusception, and abnormal perineal descent often coexist in constipated patients, as noted by defecographic study. Moreover, some of these conditions are often found in asymptomatic patients. Biofeedback is the treatment of choice for constipated patients with paradoxical puborectalis contraction; the main determinant of successful biofeedback is patient compliance. The significance of coexistent and highly prevalent variants, such as rectocele, intussusception, sigmoidocele, or abnormal perineal descent, on the success of biofeedback is unknown. This review was designed to assess whether these coexisting defecographic findings have any prognostic significance for the outcome of biofeedback.

METHODS

From July 1988 to December 1996, 209 constipated patients with paradoxical puborectalis contraction underwent biofeedback treatment after defecography. A total of 173 patients (120 females) who had more than one biofeedback session after defecography formed the study group. Defecographic findings included concomitant rectoceles, 40 (23 percent); evidence of circumferential intussusception, 17 (10 percent); sigmoidocele, 13 (8 percent); and abnormal perineal descent, 109 (63 percent).

RESULTS

Whereas 65 patients failed to complete the course of biofeedback therapy, 108 (62.4 percent) patients completed the course of biofeedback and were discharged by the therapist. Within the completed group 59 (55 percent) improved, and 49 (45 percent) patients failed biofeedback therapy. In the improved group 14 (23.7 percent) had a rectocele, 5 (8.5 percent) had intussusception, 5 (8.5 percent) had a sigmoidocele, and 37 (62.7 percent) had abnormal perineal descent. In the failure group 9 (18.4 percent) had a rectocele, 5 (10.2 percent) had an intussusception, 2 (4.1 percent) had a sigmoidocele, and 31 (63.3 percent) had abnormal perineal descent (P = not significant). The success of biofeedback was then analyzed relative to the number of coexisting conditions. Specifically, the outcome in patients with paradoxical puborectalis contraction alone and with one, two, and three other defecographic findings were compared. No statistically significant difference was found among these four groups.

CONCLUSION

Although other defecographic findings frequently coexist with paradoxical puborectalis contraction, none of the concomitant findings adversely affected the outcome of biofeedback treatment. Therefore, biofeedback can be recommended to patients with coexistent defecographic findings, with expectation of success in over 50 percent of individuals who complete the course of therapy.

Anal sensitivity test: what does it measure and do we need it? Cause or derivative of anorectal complaints

PURPOSE

This study was undertaken to determine the anal sensitivity in controls and in different patient groups and to establish factors that determine anal sensitivity.

METHODS

Anorectal function tests were performed in 387 patients with different anorectal diseases. Anal sensitivity was measured in 36 controls. Anal sensitivity was measured by means of mucosal electrosensitivity (MES) using a catheter with two electrodes placed in the anal canal. A constant current (square wave stimuli 100 microsec, pulses per second) was increased stepwise from 1 to 20 mAmp until the threshold sensation was reached. Other tests used were anal manometry (maximum basal pressure, maximum squeeze pressure, rectal compliance (maximum rectal volume and pressure), endosonography (submucosal thickness), defects and thickness of internal and external sphincter), electromyography (maximum contraction pattern, Grade 1 (solitary contractions) to Grade 4 (interference pattern)), and pudendal nerve terminal motor latency. Multiple regression analysis was performed. It was postulated that age, local conditions (anal scars, anal fissures, hemorrhoids, mucosal prolapse, proctitis, sphincter thickness and defects, and submucosal thickness), and neurologic factors could influence anal sensitivity.

RESULTS

Controls had an MES of 3.4 +/- 1.7. MES was significantly increased compared with controls in patients with fecal incontinence, soiling, hemorrhoids, mucosal prolapse, constipation, anal scars, anal surgery, and sphincter defects; patients with fecal incontinence had the highest MES (6.7 +/- 4.3; P < 0.0001). Patients with anal fissures and proctitis showed no differences compared with controls. MES correlated significantly with age (R = 0.29), maximum basal pressure (R = -0.29), maximum squeeze pressure (R = -0.32), submucosal thickness (R = 0.19), maximum contraction pattern (R = -0.39), single-fiber electromyography (R = 0.39), and maximum rectal volume and pressure (0.14). Multiple regression analysis showed that age, internal sphincter defects, and submucosal thickness significantly influenced anal sensitivity, but explained only 10 percent of the variance.

CONCLUSION

Anal sensitivity is diminished in all patients with anorectal diseases except for anal fissures and proctitis. There are correlations with other anorectal function tests. Anal sensitivity is determined for 10 percent by age, internal sphincter defects, and thickness of the submucosa. Anal sensitivity measurement, therefore, has limited clinical value and should be used in conjunction with other tests in a research setting.