Manovolumetry: a new method for investigation of anorectal function

Gastrointestinal motility and neurogastroenterology

Nordic research on gastrointestinal motility has since 1965 made substantial contributions to our current understanding of gastrointestinal function. During the last decade, the term neurogastroenterology has widened the concept of motility research into the study of gastrointestinal sensory-motor function, including the complex central nervous system interaction. The discovery of a non-adrenergic non-cholinergic (NANC) innervation of the gut in the sixties was made by considerable contributions from the Nordic countries with the Martinson group in Sweden as central innovators. Important discoveries regarding the intramural nerve ganglia as mediators of the autonomic nervous input has also been produced from this research. In clinical motility research, the study of the migrating motor complex in the small bowel has revealed its ability to act as a retroperistaltic pump in the proximal duodenum (Sweden) and its important role for gut microbial homeostasis (Norway). Also in the development of methodology to study gut sensory-motor function, the Nordic countries has contributed. Examples are the physical characteristics of the esophageal manometry catheter (Denmark), the use of ultrasound for assessment of gastric function (Norway), a temporary electrical stimulation method in patients with severe nausea and vomiting (Sweden), a rectal barostat method for clinical evaluation of recto-anal function and a colonic transit time method utilizing radio-opaque markers (Sweden). In later years, the research collaborations have increasingly become worldwide in a manner making it less easy to define pure Nordic contributions.

Rectal visceral sensitivity in women with irritable bowel syndrome without psychiatric comorbidity compared with healthy volunteers

Background. Psychiatric comorbidity and visceral hypersensitivity are common in patients with irritable bowel syndrome (IBS), but little is known about visceral sensitivity in IBS patients without psychiatric disorders. Aim. We wanted to examine rectal visceral sensitivity in IBS patients without comorbid psychiatric disorders, IBS patients with phobic anxiety and healthy volunteers. Methods. A total of thirty-eight female, non-constipated IBS patients without psychiatric disorders and eleven female IBS patients with phobic anxiety were compared to nine healthy women using a barostat double random staircase method. The non-psychiatric patients were divided into those with diarrhoea predominant symptoms and those with alternating stool habits. Results. The IBS patients without psychiatric disorders had normal visceral pressure thresholds. However, in the diarrhoea predominant subgroup, the volume discomfort threshold was reduced while it was unchanged in those with alternating stool habits. The phobic IBS patients had similar thresholds to the healthy volunteers. The rectal tone was increased in the non-psychiatric IBS patients with diarrhoea predominant symptoms and in the IBS patients with phobic anxiety. Conclusions. Non-constipated IBS patients without psychiatric disorders had increased visceral sensitivity regarding volume thresholds but normal pressure thresholds. Our study suggests that the lowered volume threshold was due to increased rectal tone.

Fecal incontinence treated with acupuncture--a pilot study

OBJECTIVES

Acupuncture has been used successfully for the treatment of urinary bladder dysfunction. The aim of this study was therefore to investigate if manual acupuncture might also affect fecal incontinence favorably.

METHODS

The study comprises 15 female patients, median age 60 years (39 -75). Before treatment and at regular intervals after acupuncture sessions the defects of anal continence were assessed. Ano-rectal function was assessed by means of recto anal manovolumetry. Each patient was submitted to one acupuncture treatment per week for a ten-week period. Subsequently, a control session was repeated once per month up to 7 months for six patients. A final functional assessment was performed at 18 months.

RESULT

Patients experienced a significant improvement in anal continence, the overall continence score which changed from 10 (3 -21) estimated before treatment to zero (0 - 7) (p<0.05) at 10 weeks. Patients with irregular bowel habits and/or loose stools reported significant improvement. On the manovolumetric variables a limited increase of resting from 25 (17-35) mmHg to 36 (20-42) mmHg, (p=0.05) and sustained squeeze anal pressure, changing from 41 (32-68) mmHg to 60 (40-100) mmHg (p<0.05) were reported. Rectal sensory function remained unchanged.

CONCLUSION

Acupuncture offers good opportunities for improving fecal incontinence. The mechanism of action is obscure but might be an effect of the "neuromodulation" of the recto-anal function similar to that explaining the favorable results achieved by sacral nerve stimulation. The concomitant regulation of disordered bowel habits may also contribute to the satisfactory results.

Anorectal manovolumetry in the decision making before surgery for slow transit constipation

BACKGROUND

Colectomy with ileorectal anastomosis for slow transit constipation (STC) is being challenged by other operations, such as segmental resections. The importance of preoperative anorectal physiology testing may therefore be increased. The aim of this study was to identify anorectal abnormalities in patients with STC, which may influence the surgical approach.

METHODS

Fifty consecutive patients with STC (43 women; median age, 49 years) and 28 controls (23 women; median age, 50 years) were examined with anorectal manovolumetry. Anal pressures and rectal volumes were recorded, at stepwise rectal distension.

RESULTS

Anal resting pressure was lower in patients (median, 54 cm H(2)O; range, 22-130) than in controls (median, 68 cm H(2)O; range, 35-100) (p<0.05). Squeeze pressure tended to be lower in patients (median, 147 cm H(2)O; range, 53-382) than in controls (median, 177 cm H(2)O; range, 65-423) (p=0.09). Rectal sensory thresholds did not differ significantly between patients and controls, although 10 patients had a threshold for filling above the 95(th) percentile of controls. Rectal compliance was increased in patients in the pressure interval 5-35 cm H(2)O (p<0.05-0.01). The threshold and amplitude of the recto-anal inhibitory reflex did not differ significantly, but the recovery of resting pressure after eliciting the reflex was lower in patients than in controls in the pressure interval 10-50 cm H(2)O (p<0.05-0.001).

CONCLUSIONS

More than half of the patients with STC deviated in some parameter. An impaired internal sphincter function and increased rectal compliance were seen. One fifth of the patients had impaired rectal sensation.

Long-term function and manovolumetric characteristics after ileal pouch–anal anastomosis for ulcerative colitis

Background

Long-term pouch function and physiological characteristics after ileal pouch–anal anastomosis (IPAA) are poorly described. The aim of this study was to undertake a prospective investigation of long-term pouch function and manovolumetric characteristics.

Methods

Forty-two patients with a median follow-up of 16 years after IPAA were included. Function was assessed using a questionnaire and a score was calculated ranging from 0 to 15 (15 being the worst). Manovolumetry was performed and pouchitis recorded. A paired analysis was conducted, as the results were compared with previous data for each patient.

Results

The median functional score was 3·5 (range 0–10) at 2 years and 5 (range 1–11) at 16 years (P = 0·013). Resting anal canal pressures were higher (P &lt; 0·001) and squeeze pressures lower (P = 0·008) at long-term follow-up. Ileal pouch volumes at distension pressures of 10, 20 and 40 cmH2O were diminished at 16 years (P &lt; 0·001, P = 0·005 and P = 0·058 respectively). The volume and pressure for first sensation and urge to defaecate were reduced. Increased age correlated positively with a poor functional score. A history of pouchitis did not affect functional or physiological characteristics.

Conclusion

Ileal pouch function declines in the long term. The reasons are unclear, but the ageing process may have an impact.

Tap-water enema for children with myelomeningocele and neurogenic bowel dysfunction

AIM

To evaluate the outcome of transrectal irrigation (TRI) using clean tap water without salt in children with myelomeningocele and neurogenic bowel problems.

METHODS

40 children (21 boys and 19 girls; aged 10 mo to 11 y) with myelomeningocele and neurogenic bowel dysfunction were treated with TRI given by a stoma cone irrigation set daily or every second day. A questionnaire on the effects on faecal incontinence, constipation and self-management was completed by the parents, 4 mo-8 y (median 1.5 y) after start. Effects on rectal volume, anal sphincter pressure and plasma sodium were evaluated before and after the start of irrigation.

RESULTS

At follow-up, 35 children remained on TRI, four had received appendicostomy, while one defecated normally. For all children but five (35/40; 85%) the procedure worked satisfactorily, but a majority found the procedure very time consuming and only one child was able to perform it independently. All children were free of constipation; most (35/40) were also anal continent. Rectal volume and anal sphincter pressure improved, while plasma sodium values remained within the normal range.

CONCLUSION

Transrectal irrigation with tap water is a safe method to resolve constipation and faecal incontinence in children with myelomeningocele and neurogenic bowel dysfunction, but it does not help children to independence at the toilet.

Magnetic resonance imaging of the rectum during distension

PURPOSE

A knowledge of the relationships between the rectum and its surrounding structures during distention may improve our understanding of the results of studies assessing rectal sensory-motor responses to distention. This magnetic resonance imaging study was designed to assess the shape of the rectum and the degree of distention at which the surrounding structures are compressed.

METHODS

Nine healthy patients underwent magnetic resonance imaging of the rectum under resting conditions and after the inflation of a plastic bag to volumes of 50, 100, 150, 200, and 250 ml. The thickness of the rectovesical space was assessed as a measure of the compression of the perirectal structures, and the perception of sensations were recorded.

RESULTS

The shape of the rectum changed from being quasicylindrical at distention volumes of <100 ml to bean-shaped at larger volumes. The thickness of the rectovesical space at a distention volume of 50 ml was the same as when the bag was not inflated, but it progressively decreased until the difference became statistically significant at distention volumes of > or = 200 ml, corresponding to a mean +/- standard deviation rectal radius of 2.66 +/- 0.37 cm. Statistically significant compression of the rectovesical space was recorded when the sensations of gas, desire to defecate, and urgency were perceived.

CONCLUSIONS

The shape of the rectum changes during distention; it significantly compresses the extrarectal structures in the tested range of distention that induces non-painful sensations. Magnetic resonance imaging is a useful means of assessing the morphologic changes in the rectum during distention.

Anorectal physiology in relation to clinical subgroups of patients with severe constipation

OBJECTIVE

The aim of this study was to evaluate anorectal physiology in relation to clinically defined subgroups of patients with idiopathic constipation and to analyse relationships between anorectal physiology and rectal evacuation.

SUBJECTS AND METHODS

One hundred consecutive patients with idiopathic constipation were clinically categorized as slow transit (n=19), outlet obstruction (n=52) and a group with mixed symptoms (n=29). They were examined by recording anal pressures and also rectal volumes in response to stepwise increases in rectal pressure (5-60 cm H2O). The manovolumetric results were compared with 28 sex and aged matched controls. Rectal evacuation was measured by computer-based image analysis of rectal emptying rate in defaecography.

RESULTS

The rectal pressure thresholds for filling, urge and pain did not differ between the groups but there were proportionally more patients in the slow transit and mixed group with thresholds for filling exceeding 25 cm H2O (P=0.04). In total, 18% of patients had impaired sensitivity which was associated with long duration of symptoms (P < 0.05). Patients with grossly impaired rectal sensitivity (filling threshold > 40 cm H2O) had impaired rectal evacuation (P < 0.05). The rectal compliance was increased in the slow transit and mixed group (P < 0.01-0.05) in the pressure interval 5-15 cm H2O. Anal resting and squeeze pressures did not differ between the groups although 7/19 in the slow transit group had values around the lower limit of controls. Slow wave frequency was lower in all patient groups (P < 0.001 vs. controls). Rectal evacuation was not related to sphincter function or to rectal compliance.

CONCLUSIONS

Clinical categorization of constipated patients defines groups where altered anorectal physiology is not uncommon. Constipation with symptoms of infrequent defaecation may be associated with impaired rectal sensitivity and increased rectal compliance whereas outlet obstruction symptoms are not clearly related to changes in anorectal physiology.

Visceral sensitivity in irritable bowel syndrome and healthy volunteers: reproducibility of the rectal barostat

The reproducibility of rectal visceral sensitivity using the barostat double-random staircase method was evaluated. We tested 15 healthy women and 18 women with irritable bowel syndrome twice. Pressure, volume, and tension were measured at first sensation of gas, stool, and discomfort. There was no significant difference between test and retest. Three different indexes were used as measures of reproducibility. The intraclass correlation coefficients, considered to demonstrate acceptable reproducibility when higher than 0.80, ranged from 0.76 to 0.93 in the healthy volunteers and from 0.53 to 0.88 in the patients. The pooled coefficients of variation ranged from 10 to 24% in the healthy volunteers and from 11 to 49% in the patients. The repeatability coefficients are also given. The results indicate that barostat visceral sensitivity measurements in the rectum may be applicable when comparing groups of subjects.

Randomized clinical trial comparing conservative and surgical treatment of neurogenic faecal incontinence

Background

The treatment of choice in idiopathic (neurogenic) faecal incontinence is controversial. In a randomized study levatorplasty was compared with anal plug electrostimulation of the pelvic floor with respect to functional outcome and physiological variables.

Methods

Thirty-one patients underwent levatorplasty and 28 anal plug electrostimulation of the pelvic floor over 3 years. The results were evaluated at 3, 12 and 24 months after completion of treatment by means of a validated questionnaire and anorectal manometry and manovolumetry.

Results

Incontinence scores were significantly reduced during the entire observation period in both groups (P &lt; 0·001) as was the use of pads (P = 0·003 to P &lt; 0·001). The proportion of patients reporting improvement in physical and social handicap was greater in the levatorplasty group after 3, 12 and 24 months (P = 0·036 to P &lt; 0·001). No significant changes in physiological variables were observed in either group.

Conclusion

Better results were obtained with levatorplasty than with anal plug electrostimulation of the pelvic floor in patients with idiopathic (neurogenic) faecal incontinence. Levatorplasty should be therefore be considered the treatment of choice for this condition.

Pathophysiology of adult fecal incontinence

Fecal incontinence occurs when the normal anatomy or physiology that maintains the structure and function of the anorectal unit is disrupted. Incontinence usually results from the interplay of multiple pathogenic mechanisms and is rarely attributable to a single factor. The internal anal sphincter (IAS) provides most of the resting anal pressure and is reinforced during voluntary squeeze by the external anal sphincter (EAS), the anal mucosal folds, and the anal endovascular cushions. Disruption or weakness of the EAS can cause urge-related or diarrhea-associated fecal incontinence. Damage to the endovascular cushions may produce a poor anal "seal" and an impaired anorectal sampling reflex. The ability of the rectum to perceive the presence of stool leads to the rectoanal contractile reflex response, an essential mechanism for maintaining continence. Pudendal neuropathy can diminish rectal sensation and lead to excessive accumulation of stool, causing fecal impaction, mega-rectum, and fecal overflow. The puborectalis muscle plays an integral role in maintaining the anorectal angle. Its nerve supply is independent of the sphincter, and its precise role in maintaining continence needs to be defined. Obstetric trauma, the most common cause of anal sphincter disruption, may involve the EAS, the IAS, and the pudendal nerves, singly or in combination. It remains unclear why most women who sustain obstetric injury in their 20s or 30s typically do not present with fecal incontinence until their 50s. There is a strong need for prospective, long-term studies of sphincter function in nulliparous and multiparous women.

Increased anal resting pressure and rectal sensitivity in Crohn's disease

PURPOSE

Anal pathology occurs in 20 to 80 percent of patients with Crohn's disease in which abscesses, fistulas, and fissures account for considerable morbidity. The etiology is not clearly defined, but altered anorectal pressures may play a role. This study was designed to investigate anorectal physiologic conditions in patients with Crohn's disease compared with healthy controls.

METHODS

Twenty patients with Crohn's disease located in the ileum (n = 9) or the colon (n = 11) without macroscopic proctitis or perianal disease were included. All were subjected to rectal examination, anorectal manometry, manovolumetry, and rectoscopy. Comparison was made with a reference group of 173 healthy controls of whom 128 underwent anorectal manometry, 29 manovolumetry, and 16 both examinations.

RESULTS

Maximum resting pressure and resting pressure area were higher in patients than in controls (P = 0.017 and P = 0.011, respectively), whereas maximum squeeze pressure and squeeze pressure area were similar. Rectal sensitivity was increased in patients expressed as lower values both for volume and pressure for urge (P = 0.013 and P = 0.014, respectively) as well as maximum tolerable pressure (P = 0.025).

CONCLUSIONS

This study demonstrates how patients with Crohn's disease without macroscopic proctitis have increased anal pressures in conjunction with increased rectal sensitivity. This may contribute to later development of anal pathology, because increased intra-anal pressures may compromise anal circulation, causing fissures, and also discharging of fecal matter into the perirectal tracts, which may have a role in infection and fistula development.

Short-term sacral nerve stimulation for functional anorectal and urinary disturbances: results in 40 patients: evaluation of a new option for anorectal functional disorders

PURPOSE

There are several options in the treatment of fecal incontinence; it is often difficult to choose the most appropriate, adequate treatment. The consolidated experience gained in the urologic field suggests that sacral nerve stimulation may be a further option in the choice of treatment. The aim of our study was to evaluate the preliminary results of the peripheral nerve evaluation test obtained in a multicenter collaborative study on patients with defecatory and urinary disturbances.

METHODS

Forty patients (9 males; mean age, 50.2; range, 26-79 years) underwent the peripheral nerve evaluation test, 28 (70 percent) for fecal incontinence and 12 (30 percent) for chronic constipation. Fourteen (35 percent) patients also had urinary incontinence; six had urge incontinence, two had stress incontinence, and six had retention incontinence. Associated diseases were scleroderma (2 patients), spinal injuries (4 patients), and syringomyelia (1 patient). All the patients underwent preliminary investigations with anorectal manometry, pudendal nerve terminal motor latency testing, anal ultrasound, defecography, and if required, urodynamic tests. The electrode for sacral nerve stimulation was positioned percutaneously under local anesthesia in the S2 (4), S3 (34), or S4 (1) foramen unilaterally (1 patient not accounted for because of no response to acute test), based on the best motor and subjective responses of paresthesia of the pelvic floor. Stimulation parameters were average amplitude, 2.8 (range, 1-6) V and average frequency, 15 to 25 Hz.

RESULTS

The mean duration of the tests was 9.9 (range, 7-30) days; tests lasting fewer than seven days were not evaluated. There were four early displacements of the electrode. In 22 of the 25 evaluable patients with fecal incontinence, there was an improvement of symptoms (88 percent), and 11 (44 percent) were completely continent to liquid or solid stools, whereas in 7 symptoms were unchanged. Mean number of episodes of liquid or solid stool incontinence per week was 8.1 (range, 4-18) in the prestimulation period and 1.7 (range, 0-12) during the peripheral nerve evaluation test. (P = 0.001; Wilcoxon's signed-rank test). The most important manometric findings were: increase of maximum rest pressure (39.4 +/- 7.3 vs. 54.3 +/- 8.5 mmHg; P = 0.014, Wilcoxon's test) and maximum squeeze pressure (84.7 +/- 8.8 vs. 99.5 +/- 1.1 mmHg; P = 0.047), reduction of initial threshold (63.6 +/- 5.2 vs. 42.4 +/- 4.7 ml; P = 0.041) and urge sensation (123.8 +/- 0.6 vs. 78.3 +/- 8.9 ml; P = 0.05). An improvement was also found in patients with constipation, with reduction in difficulty emptying the rectum, with prestimulation at 7 (range, 2-21) episodes per week and end of peripheral nerve evaluation test at 2.1 (range, 0-6) episodes per week, P < 0.01) and in the number of unsuccessful visits to the toilet, which dropped from 29.2 (7-24) to 6.7 (0-28) per week (P = 0.01). The most important manometric findings in constipated patients were an increase in amplitude of maximum squeeze pressure during sacral nerve stimulation (prestimulation, 63 +/- 0 mm Hg; end of peripheral nerve evaluation test, 78 +/- 1 mm Hg; P = 0.009) and a reduction in rectal volume for urge threshold (prestimulation, 189 +/- 52 ml; end of peripheral nerve evaluation test, 139 +/- 45 ml; P = 0.004).

CONCLUSIONS

In functional bowel disorders short-term sacral nerve stimulation seems to be a useful diagnostic tool to assess patients for a minor invasive therapy alternative to conventional surgical procedure.

Neuromodulation for fecal incontinence: outcome in 16 patients with definitive implant. The initial Italian Sacral Neurostimulation Group (GINS) experience

PURPOSE

Sacral nerve modulation appears to offer a valid treatment option for some patients with fecal incontinence and functional defects of the internal anal sphincter or of the striated muscle.

METHODS

Sixteen patients with fecal incontinence (4 males; mean age, 51.4 (range, 27-79) years) with intact or surgically repaired (n = 1) anal sphincter underwent permanent sacral nerve stimulation implant. Cause was traumatic in two patients, and associated disorders included scleroderma (2 patients) and spastic paraparesis (1 patient); eight (50 percent) of the patients also had urinary incontinence, and two (12.5 percent) had nonobstructive urinary retention. All patients were selected on the basis of positive findings from at least one peripheral nerve evaluation. The stimulating electrode was positioned in the S2 (1 patient), S3 (14 patients), or S4 (1 patient) sacral foramen.

RESULTS

Mean follow-up was 15.5 (range, 3-45) months. Mean preimplant Williams score decreased from 4.1 +/- 0.9 (range, 2-5) to 1.25 +/- 0.5 (range, 1-2) (P = 0.01, Wilcoxon test), and the number of incontinence accidents for liquid or solid stool in 14 days decreased from 11.5 +/- 4.8 (range, 2-20) before implant to 0.6 +/- 0.9 (range, 0-2) at the last follow-up. Important manometric data were an increase in mean maximal pressure at rest of 37.7 +/- 14.9 mmHg (implantable pulse generator 49.1 +/- 18.7, P = 0.04) and in mean maximal pressure during squeeze (prestimulation 67.3 +/- 21.1 mmHg, implantable pulse generator 82.6 +/- 21.0, P = 0.09).

CONCLUSIONS

Neuromodulation can be considered an option for fecal incontinence. However, an accurate clinical and instrumental evaluation and careful patient selection are required to optimize outcome.

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 defecation, the compliance of the rectal wall is normal.

Long-term outcome after colectomy in severe idiopathic constipation

OBJECTIVE

The specific aim of the investigation was to assess the long-term results of subtotal colectomy with ileorectal anastomosis in patients with severe idiopathic constipation.

PATIENTS AND METHODS

40 patients with severe idiopathic constipation were operated on between 1981 and 1993. Patients were accepted for a colectomy and an ileo-rectal anatomosis after a thorough gastro-intestinal investigation. Pre-operative bowel frequency was less than 2 movements per week, and slow transit was documented. Postoperative complications occurred in eight patients. Early re-operation was performed in 2 patients for small bowel obstruction.

RESULTS

Mean follow-up was 11 (range 5-16) years. The defaecation frequency at follow-up was 3.0 +/- 1.9 per day. Twenty-nine patients stated that they were satisfied and 11 were dissatisfied with the procedure. The outcome did not correlate with observed signs of outlet obstruction, blunted rectal sensation or presence of a psychiatric diagnosis. At 5-16 years after the procedure 33 patients still retain the ileo-rectal anastomosis. Seven patients have had further procedures: Five patients have an ileo-anal pouch, one has a continent ileostomy and one has a conventional ileostomy. Small bowel obstruction was encountered in 17 patients, in 10 of these surgical treatment was necessary.

CONCLUSION

It is concluded that colectomy and ileorectal anastomosis for the treatment of severe idiopathic constipation causes an increase in the number of bowel motions, but is deemed successful only by 3 out of 4 patients. Secondary morbidity is considerable.

Sacral nerve stimulation for treatment of fecal incontinence: a novel approach for intractable fecal incontinence

PURPOSE

Many patients with fecal incontinence demonstrate a functional deficit of the internal anal sphincter or the external sphincter muscles without any apparent structural defects. Few patients are amenable to repair or substitution of the sphincter. However, sacral nerve stimulation appears to offer a valid treatment option for fecal incontinence. The objectives of this study were: to evaluate the efficacy of temporary stimulation of the sacral nerve roots (percutaneous nerve evaluation) in patients with functional fecal incontinence; to determine the mechanisms of possible improvement; and to evaluate if temporary stimulation could be reproduced and maintained by implanting a permanent neurostimulation system.

METHODS

Twenty-three patients with fecal incontinence, 18 females and 5 males, median age of 54.9 years (range 28-71), underwent a percutaneous nerve evaluation test. Eleven patients (47.8 percent) also had urinary disorders: urge incontinence (4), stress incontinence (3), and retention (4). Associated disorders included perineal and rectal pain (1), spastic paraparesis (1), and syringomyelia (1). All patients underwent a preliminary evaluation using stationary anal manovolumetry, pudendal nerve terminal motor latency measurements, and anal ultrasound. A percutaneous electrode for the stimulation of the sacral nerve roots was positioned at the level of the third sacral foramen (S3) in 20 patients and S2 in 2 patients (1 patient missing). Stimulation parameters used were: pulse width 210 microsec, frequency 25 Hz, and average amplitude of 2.8 V (range 1-6). The electrode was left in place for a minimum of 7 days. Five patients were successively implanted with a permanent sacral electrode with a stimulation frequency of 16 to 18 Hz and amplitude of 1.1- 4.9 V.

RESULTS

Seventeen of the 19 patients (89.4 percent) who completed the minimum percutaneous nerve evaluation period of 7 days (median 10.7 (range 7-30)), had a reduction of liquid or solid stool incontinence by more than 50 percent, and fourteen (73.6 percent) were completely continent for stool. The most important changes revealed by manovolumetry were an increase in resting pressure (P < 0.001) and voluntary contraction (P = 0.041), reduction of initial pressure for first sensation (P = 0.049) and urge to defecate (P = 0.002), and a reduction of the rectal volume for urge sensation (P = 0.006). The percutaneous nerve evaluation results were reproduced at a median follow-up of 19.2 months (range 5 to 37) in the 5 patients who received a permanent implant.

CONCLUSIONS

Temporary stimulation of the sacral roots (percutaneous nerve evaluation) can be of help in those patients with fecal incontinence, and the results are reproduced with permanent implantation. The positive effect on continence seems to be derived from not only the direct efferent stimulation on the pelvic floor and the striated sphincter muscle, but also from modulating afferent stimulation of the autonomous neural system, inhibition of the rectal detrusor, activation of the internal anal sphincter, and modulation of sacral reflexes that regulate rectal sensitivity and motility.

Results of surgical treatment for faecal incontinence

BACKGROUND

This prospective study was designed to evaluate the results of anterior levatorplasty and sphincteroplasty for faecal incontinence with respect to symptomatic and physiological outcome.

METHODS

Thirty-one patients with idiopathic (neurogenic) faecal incontinence underwent anterior levatorplasty and 20 patients with traumatic anal sphincter injury underwent anal sphincteroplasty. The outcome of repair was evaluated at 3 and 12 months using a validated questionnaire and anorectal manometry/manovolumetry.

RESULTS

Eighteen of 31 patients in the levatorplasty group reported continence to solid and liquid stools 1 year after operation compared with two patients before surgery (P < 0.01). The corresponding figures in the sphincteroplasty group were ten and two of 20 respectively (P < 0.05). The incontinence score was improved in both groups after 1 year, from a median score of 14 to 3 in the levatorplasty group (P < 0.001) and from 8.5 to 3.5 in the sphincteroplasty group (P < 0.01). Improvements in the degree of social and physical handicap were also observed in both groups. No changes were seen in anal canal pressures or rectal sensation in either group.

CONCLUSION

Despite different aetiologies and surgical approaches, anterior levatorplasty and sphincteroplasty yielded similarly successful results in patients with faecal incontinence. Although a marked symptomatic improvement was seen in both groups, no associated physiological alterations could be detected. The reason for the improvement is thus unclear, but it may result from a stenosing effect in the anal canal.

Results of neurophysiologic evaluation in fecal incontinence

PURPOSE

Several methods of neurophysiologic assessment exist in the investigation of patients with fecal incontinence. However, the clinical significance of the information gained is uncertain. The aim of this prospective study was to evaluate the results of pudendal nerve terminal motor latency and fiber density in relation to clinical variables and manometric measurements.

METHODS

Seventy-two patients with fecal incontinence (63 women; mean age, 62; range, 24-81 years) responded to a bowel questionnaire and underwent anorectal manovolumetry, anal ultrasonography, defecography, and electromyography, including pudendal nerve terminal motor latency and fiber density.

RESULTS

Pudendal neuropathy (pudendal nerve terminal motor latency > 2.5 ms) was found in 46 percent and increased fiber density (> 1.7) in 82 percent. Pudendal neuropathy and increased fiber density were most common in patients with rectal prolapse or intra-anal intussusception. No difference was seen concerning anal resting and incremental pressures, rectal compliance, rectal sensibility or severity of incontinence in patients with unilateral, bilateral, or marked (> 4 ms) pudendal neuropathy vs. patients with normal pudendal nerve terminal motor latency. In contrast, patients with increased fiber density had lower incremental pressures (P < 0.05) and stated decreased rectal sensibility (P < 0.05) compared with those with normal fiber density. These differences were most pronounced in patients with neurogenic or idiopathic incontinence.

CONCLUSIONS

Pudendal neuropathy and increased fiber density are common in patients with fecal incontinence. Fiber density but not pudendal nerve terminal motor latency was correlated with clinical and manometric variables. The severity of nerve injury correlated with anal motor and sensory function in patients with neurogenic or idiopathic incontinence. The routine use of pudendal nerve terminal motor latency in the assessment of patients with fecal incontinence can be questioned.

Effects of alosetron on gastrointestinal transit time and rectal sensation in patients with irritable bowel syndrome

BACKGROUND

Alosetron, a 5-HT3-receptor antagonist, relieves abdominal pain and improves bowel function in non-constipated, female patients with irritable bowel syndrome. 5-HT3 antagonists delay colonic transit, increase colonic compliance, and increase small intestinal water absorption.

AIM

To evaluate the effects of alosetron on gastrointestinal and colonic transit, rectal compliance and rectal sensation in irritable bowel syndrome.

METHODS

A double-blind, placebo-controlled, two-dose study of alosetron was performed in 25 non-constipated irritable bowel syndrome patients, with paired studies before and after 4 weeks of treatment with placebo (n=5), 1 mg alosetron (n=10) or 4 mg (n=10) alosetron b.d. Gastrointestinal and colonic transit were measured by scintigraphy. Rectal compliance and sensation were assessed by rectal balloon distention with a barostat.

RESULTS

There was a trend (P=0.06) for 1 mg alosetron to increase rectal compliance (median pressure at half maximum volume 11 mmHg after alosetron vs. 15.6 mmHg before alosetron). The 1 mg b.d. alosetron dose non-significantly retarded proximal colonic transit. Alosetron and placebo reduced sensory scores relative to baseline values; none of the changes induced by alosetron was significant relative to placebo.

CONCLUSIONS

Alosetron had no significant effect on gastrointestinal transit or rectal sensory and motor mechanisms in non-constipated irritable bowel syndrome patients in this study. Alosetron's effects on colonic sensorimotor function and central sensory mechanisms deserve further evaluation.

The effects of biofeedback on rectal sensation and distal colonic motility in patients with disorders of rectal evacuation: evidence of an inhibitory rectocolonic reflex in humans?

OBJECTIVE

Abnormalities of descending colon motility reported in a subset of patients with rectal evacuation disorders are consistent with a rectocolonic inhibitory reflex. Our aims were to evaluate distal colon motor function and rectal sensation in such patients and assess effects of biofeedback (BF) training on these functions.

METHODS

Seven patients (five women, two men; mean age 36 yr) with rectal evacuation disorders were studied before and after 10-days biofeedback training; six healthy volunteers (five women, one man; mean age 30 yr) were studied once. Colonic compliance, motility, sensation thresholds, and perception scores during standardized rectal distentions were measured using two barostat-manometry assemblies inserted into the cleansed colon with the aid of flexible sigmoidoscopy.

RESULTS

Sigmoid compliance, fasting, and postprandial motility index, and perception thresholds were similar in controls and patients before and after biofeedback training. Postprandial sigmoid tone tended (p = 0.09) to be lower in patients than controls; after biofeedback, postprandial tone was comparable to that in controls. Rectal urgency scores at 24 mm Hg distention were greater in patients than in controls (p = 0.02 for both). After biofeedback, there were trends for lower perceptions of urgency to defecate (7.6 +/- 1.1 cm pre- vs 5.3 +/- 1.5 post-; p = 0.04) at 24 mm Hg; conversely, gas sensation at 12 mm Hg was higher (1.2 +/- 0.5 cm pre- vs 3.3 +/- 0.6 post-; p = 0.05).

CONCLUSIONS

Normalization of rectal evacuation and postprandial sigmoid tone in patients with evacuation disorders by biofeedback training supports the presence of a rectocolonic inhibitory reflex. Effect of biofeedback on rectal sensation in these patients requires further study.

Preservation of continence after posterior sagittal surgery

PURPOSE

An animal study was performed to evaluate the effect of posterior sagittal pararectal mobilization on anorectal sphincter function.

MATERIALS AND METHODS

We initially divided 11 juvenile pigs into 3 groups: group 1-anesthesia alone (3), group 2-posterior sagittal incision alone (4) and group 3-posterior sagittal incision with unilateral pararectal dissection (4). Two animals in group 1 subsequently underwent posterior sagittal incision with circumferential pararectal dissection (group 4). The anal canal was preserved intact in all animals. Anorectal sphincter manometry was performed preoperatively, and 2, 4, 8 and 12 weeks postoperatively. Electromyography was performed 12 weeks postoperatively. Anorectal sphincter muscle complexes were harvested for histological examination.

RESULTS

All animals had postoperative bowel continence. Postoperatively manometry revealed no difference from preoperative measurements in all study groups (p = 0.90). Electromyography and histological examination of the anorectal sphincters were normal in all but 2 animals. Denervation injury and histological atrophy were detected after repair of inadvertent enterotomy in 1 animal following unilateral pararectal dissection, and polyphasic motor unit potentials implying reinnervation were detected in another after circumferential pararectal mobilization.

CONCLUSIONS

These results indicate that posterior sagittal incision and unilateral pararectal mobilization cause no permanent injury to the anorectal sphincter. However circumferential pararectal dissection or repair of a rectal injury may cause measurable changes in sphincter function.

Disturbances of ano-rectal function in multiple sclerosis

Thirty patients with multiple sclerosis (MS) [18 men and 12 women, mean age 40 years (range 22-50), disease duration 12 years (range 0.5-34), Kurtzke's Expanded Disability Status Score 6.0 (range 4.0-7.5)] were interviewed about bowel symptoms and studied using ano-rectal manometry. The results were compared with findings in healthy controls. Twenty-eight had bowel symptoms: 8 constipation, 10 constipation and infrequent faecal urgency, 4 infrequent faecal incontinence and 6 frequent faecal incontinence. Anal sphincter pressure at rest was significantly reduced in MS patients 69 (SD 17) cm H2O, compared with 92 (SD 15) cm H2O in controls, and the external sphincter contraction force was also significantly reduced. Rectal sensation and rectal compliance were reduced and the ano-rectal inhibition reflex (defaecation reflex) required a higher rectal pressure to be elicited in the patients. Upon rectal filling, an early external sphincter excitation was seen. The presence of faecal incontinence correlated strongly with reduced rectal sensation. The findings suggest that faecal incontinence can at least partly be explained by low anal sphincter pressure and poor rectal sensation. The findings of early sphincter excitation and increased threshold of ano-rectal inhibition reflex may be an important pathophysiological factor for constipation in MS patients.

Anorectal manovolumetry in the diagnosis of fecal incontinence

PURPOSE

This study was designed to investigate rectal reservoir function and anal pressures in patients with fecal incontinence using anorectal manovolumetry and to evaluate the reproducibility of the investigation.

METHODS

Forty-eight patients with fecal incontinence were investigated with respect to anal pressures and rectal volume changes and sensibility in response to stepwise increased rectal pressures (5-60 cm of H2O). Patients with known rectal wall diseases were excluded. Results were compared with those of 25 control subjects investigated in a similar manner. In ten individuals in the latter group, investigation was repeated after 5 minutes and 24 hours.

RESULTS

Resting pressure (RP), squeezing pressure (SP), and the difference between SP and RP was lower in patients than in controls (P < 0.0001). There was no significant difference between patients and controls concerning rectal sensibility or compliance (P > 0.05), but there was a correlation between RP and rectal compliance (r = 0.25; P < 0.05) and between SP and rectal compliance (r = 0.30; P < 0.01). There was good reproducibility of RP and SP after five minutes (r = 0.88-0.92; P < 0.001). The day-to-day variation was larger for RP (r = 0.52; P > 0.05) compared with SP (r = 0.89; P < 0.001). Rectal compliance at 40 cm of H2O was reproducible after 5 minutes (r = 0.98; P < 0.0001) and 24 hours (r = 0.88; P < 0.01).

CONCLUSIONS

These results indicate that the primary defect in incontinent patients is a sphincter dysfunction. Any reduction in rectal compliance is likely to be a secondary phenomenon.

Anal and rectal motility responses to distension of the urinary bladder in man

Recto-anal motility response to bladder distension was studied under general anaesthesia in 12 patients undergoing intestinal resection for Crohn's disease of the small intestine or colonic cancer. The effect of epidural anaesthesia on anal tone and on the motility response to bladder distension was studied in six of these patients. An anal pressure increase on bladder distension was observed in all individuals. No motility response was noted in the rectum. The anal pressure response to bladder distension was abolished by epidural anaesthesia. It was concluded that anal pressure in man under general anaesthesia was tonically influenced by the thoracolumbar sympathetic outflow. An excitatory vesico-anal reflex was demonstrated. It appears as this reflex is mediated via the spinal cord.

Rectal compliance determined by rectal endosonography. A new application of endosonography

PURPOSE

The aim of this study was to develop a method for determination of rectal compliance that allows direct measurement of corresponding changes in the rectal cross-sectional area or perimeter and rectal pressure.

METHODS

We developed an anal probe for transrectal endosonography. The probe was tested in vitro, and rectal compliance of six healthy patients was determined.

RESULTS

In vitro measurements proved the method to be well reproducible. The method allowed calculation of an endosonographic rectal compliance, which correlated well with rectal compliance measured by the standard method.

CONCLUSION

Endosonographic determination of rectal compliance is possible, and the endosonographic method may give a more precise and reproducible estimation of rectal compliance.

Loperamide improves anal sphincter function and continence after restorative proctocolectomy

The physiological and clinical effects of loperamide treatment versus placebo were investigated in a randomized, double-blind, crossover study in patients operated with restorative proctocolectomy. Sixteen patients operated with endoanal mucosectomy and a handsewn ileal pouch-anal anastomosis and 14 patients operated with abdominal proctocolectomy and stapling of the pouch to the top of the anal canal were studied. While loperamide treatment increased resting anal pressure in both groups of patients by approximately 20% (P < 0.05), squeeze pressure was not affected. Loperamide did not affect pouch volume or contractility. Sensory thresholds and the recto/pouch-anal inhibitory reflex were not influenced by loperamide treatment. Clinical function was improved, with a reduced bowel frequency and an improved nighttime continence, with less soiling (P < 0.05) as well as need to wear a protective pad.

Abdominal rectopexy for rectal prolapse. Influence of surgical technique on functional outcome

PURPOSE

The aim of this study was to investigate the influence of surgical technique on functional and manovolumetric results in patients treated with Marlex mesh abdominal rectopexy.

METHODS

The lateral ligaments were completely divided (the Wells procedure) in 16 patients and preserved (the Ripstein procedure) in 16 patients. Clinical and physiologic assessment were performed before and at 3, 6, and 12 months after operation.

RESULTS

Improvement of continence was similar. Bowel regulation problems which were unchanged after the Ripstein procedure increased significantly after the Wells procedure (P < 0.01). Rectal volume became reduced in the group who received the Wells procedure (225 ml vs. 115 ml, P < 0.05 at one year), but remained unchanged after receiving the Ripstein procedure. The pressure thresholds required to elicit sensation of rectal filling and defecation urge were increased after the Wells procedure (15 cm of H2O vs. 25 cm of H2O, P < 0.05 and 25 cm of H2O vs. 45 cm of H2O, P < 0.05, respectively). In the Ripstein group there was only a slight increase of the threshold for urge (P < 0.05).

CONCLUSION

The Wells procedure was followed by severe rectal dysfunction accompanied by increased constipation and evacuation problems. The Ripstein procedure, preserving the lateral ligaments, appears not to affect such symptoms adversely. On the other hand, improvement is not likely to occur.

Does the level of stapled ileoanal anastomosis influence physiologic and functional outcome?

PURPOSE

The aim of this investigation was to ascertain how the length of anal canal preserved above the dentate line in stapled end-to-end ileoanal anastomosis influenced late outcome.

METHODS

Two groups, high cuff group and low cuff group of nine subjects with stapled anastomosis, matched for sex, age, pouch configuration, and mean follow-up, representing the highest (median, 2.5 cm) and lowest (median, 0.7 cm) anal cuff lengths in our series, were selected. Physiologic and functional parameters were appraised preoperatively, at the time of ileostomy closure, and at 1, 3, 6, and 12 months after reestablishment of intestinal continuity.

RESULTS

At one year, the drop in mean anal canal resting pressure was 13 percent in the high cuff group (not significant) and 31 percent in the low cuff group (P < 0.05); mean maximum squeezing pressure did not differ significantly from preoperative values in both groups. The mean volume of the ileal pouch was higher in the low cuff group at all insufflation pressures. The rectoanal inhibition reflex reappeared in four high cuff group patients and in none of the low cuff group patients. Mean distention pressure (cm H2O) and volume (ml) eliciting urge sensation were 80 and 360 in the low cuff group compared with 40 and 240 in the high cuff group (P < or = 0.05). Daytime bowel movements and night incontinence were significantly better in the low cuff group. No statistical differences were observed for night stool frequency, daytime incontinence, pad use (day and night), discrimination between gas and feces, ability to defer evacuation, and difficulty in emptying the pouch.

CONCLUSION

Patients with stapled anastomoses and a low rectal cuff length, despite presenting lower anal resting pressure and absence of rectoanal inhibition reflex, had a better functional outcome in terms of continence than those with a high cuff length.

Anorectal function

A review in a historic perspective of the present knowledge of anorectal physiology is presented. The techniques used in the anorectal physiology laboratory are discussed. Application of new sophisticated techniques to anorectal physiology research in recent years continue to improve our knowledge of anorectal function. Anal continence and defecation depend on both the anal sphincter and the rectum. The assessment of patients with functional anorectal diseases should include a more complete physiologic evaluation of the anorectum than used previously.

Biomechanical wall properties of the human rectum. A study with impedance planimetry

Biomechanical properties of the rectal wall were studied in 17 healthy adult volunteers (nine men and eight women). With impedance planimetry it is possible to obtain simultaneous measurements of pressure and rectal cross sectional area (CSA) during balloon inflations. Rectal distensions were done with an intraluminal balloon using specified pressures up to 40 cmH2O above baseline rectal pressure. Balloon inflation elicited a phase of rapid increase in rectal CSA followed by a phase of slow increase until a steady state was reached. Steady state occurred within 67 to 140 seconds with the shortest period at the highest distension pressures. Steady state rectal CSA values had a non-linear relation to increasing distension pressure. Rectal CSA values in women showed a tendency of being slightly higher than male values at all pressure steps with a significant difference at 3 and 5 cm H2O. Biomechanical parameters were calculated from rectal CSA pressure relations. Circumferential wall tension increased in a linear way. Rectal compliance decreased in a non-linear way with no further decline between 30 and 40 cmH2O. The pressure elastic modulus increased steeply until a distension pressure of 35 cmH2O with no further increase to 40 cmH2O. This suggests that rectal tone is reduced as the muscle fails to resist further distension at 35 cmH2O and higher pressures. Impedance planimetry offers new possibilities for investigation of anorectal physiology through the study of segmental biomechanical wall properties of the human rectum.

Measurements of duodenal wall motility, mucosal fluid transport and alkaline secretion. Description and evaluation of a methodological approach in the anaesthetized cat

This paper describes and evaluates a method for simultaneous recordings of duodenal motility and mucosal secretions in chloralose-anaesthetized cats. Biliary and pancreatic secretions were diverted by separate cannulation of each duct. A 2 cm segment of the proximal duodenum was isolated between two luminally situated balloons (the proximal balloon being positioned immediately distal to the pylorus). Each balloon was connected to a barostatic device maintaining a constant pressure within the balloon independent of the degree of contraction. Motor activity in the duodenal wall was recorded as changes in balloon volume. The duodenal segment was perfused at a constant rate with isotonic saline containing [14C]PEG 4000 as a non-absorbable marker. The recovered perfusate was sampled in 5 min fractions and analysed with regard to alkalinity (back titration) and concentration of marker (liquid scintillation). Net alkalinization and net fluid transport was calculated with conventional equations. The sensitivity of the analytical procedures was tested bench-side. The technique was evaluated in vivo during basal conditions and during acid exposure of the mucosa. Exposing the duodenal segment to 30 mM HCl induced a marked change in the duodenal functional state with the occurrence of a polarized duodenal motility pattern, net fluid secretion and an increased alkaline secretion.

Possible role of the autonomic nervous system in sphincter impairment after restorative proctocolectomy

Peroperative manometry was performed in 12 patients operated on with endoanal proctectomy and a hand-sewn pouch-anal anastomosis and in 12 in whom proctectomy was performed entirely from above, with the ileal pouch stapled to the top of the anal canal. Results from both groups showed that division of the superior rectal artery reduced the median (95 per cent confidence interval (c.i.)) resting anal pressure from 77.5 (69.9-83.3) mmHg to 64.5 (55.2-70.0) mmHg (P < 0.01). Complete rectal mobilization to the pelvic floor decreased resting pressure by an additional 22 per cent, to a median of 50.0 (95 per cent c.i. 40.1-53.5) mmHg (P < 0.01). After completion of anastomosis, irrespective of the operative technique used, a further decline in median pressure to 35.0 (95 per cent c.i. 26.0-47.7) mmHg could be demonstrated (P < 0.05). This study indicates that anal sphincter pressure is reduced to a similar extent after hand-sewn and stapled anastomoses. Injury to the autonomic nervous supply to the anal sphincter mechanism might be the major cause for this reduction.

The role and technique of ambulatory anal manometry

Static anal manometry has proved itself a reliable, reproducible and objective assessment of sphincter function in the investigation of disorders of defecation and continence. Despite this, it gives only very limited information on sphincter function due to the unphysiological nature of its measurement. Technical advances, particularly in digital data storage, have made the recording of anal pressure in a normal environment for prolonged periods of time possible. This offers an improved understanding both of anal activity and the interaction of rectal and anal function in normal and pathological states. In normal subjects anal function during a number of normal physiological events such as micturition, passage of flatus and sleep have been investigated. The sampling reflex has been further defined. Abnormalities of the sampling reflex, rectal activity and slow wave activity in the anal sphincter have been demonstrated in a number of pathological conditions of the anorectum and in the states of incontinence or constipation. Effective ambulatory anal manometry remains in its infancy. With continuing advances it offers exciting possibilities in defining normal or abnormal activity of the anorectum and in the investigation of patients with disorders of defecation and continence.

The internal anal sphincter: mechanisms of control and its role in maintaining anal continence

The human IAS has particular structural and functional characteristics. This smooth muscle constantly generates rhythmic electrical slow waves, but no action potentials. The slow waves are linked to calcium fluxes and both are essential for mechanical activity, i.e. the ASPW. The IAS is pharmacologically characterized by the presence of alpha excitatory and beta inhibitory adrenergic receptors. Cholinergic drugs have an indirect effect through the release of an inhibitory neurotransmitter, very probably VIP, from NANC nerves. The myogenic activity of the IAS is enhanced by its extrinsic sympathetic innervation. Thus, at rest, the IAS is in a state of partial tetanus and contributes approximately 55% of the MABP. Because the IAS ring cannot be completely closed, the anal mucosa and the haemorrhoidal plexuses fill the gap. By compressing these tissues, the IAS perfectly closes the anal canal to retain not only solids but also fluid stool and gas. Acute rectal distension and rectal activity, mainly through intramural pathways, induce reflex IAS relaxation, permitting the rectal contents to be sampled by receptors in the upper anal canal while continence is temporarily maintained by EAS activity and by expansion of the haemorrhoidal cushions. There is a correlation between the volume of rectal distension and the parameters of IAS relaxation. At maximal IAS relaxation, ASPW are absent, indicating the completeness of the inhibition. Although this RAIR is not essential for defecation, insufficient relaxation may be implicated in constipation. Hyperactivity of the IAS resulting in a high MABP and AUSPW has been considered both as a cause and as an effect in haemorrhoids and anal fissure. Continence for fluids and gas is impaired if IAS activity is decreased (i.e. a low MABP), either by direct trauma or by damage of its sympathetic innervation. Severe faecal incontinence will develop when the contractility of both the IAS and the EAS is affected.

The effects of atropine or benzilonium on pelvic pouch and anal sphincter functions

Anticholinergic drugs are used on an empirical basis for treatment of functional disturbances after restorative proctocolectomy, but their mode of action on ileal pouch performance is mainly unknown. We studied the acute effects of atropine or benzilonium on pouch characteristics and anal sphincter function in 20 patients with a pelvic pouch. Pouch volume was increased by 27% by atropine at distension with 20 cm H2O (p less than 0.01). Benzilonium tended to have a similar effect, but the changes did not reach statistical significance (p = 0.06). Pouch contractility, as reflected by volume fluctuations and pressure changes during distension, was almost abolished by both drugs. Sensory thresholds for sense of filling and, particularly, urge were raised. Resting anal pressure was slightly lowered, whereas no significant effect was found on maximal squeeze pressure. In conclusion, anticholinergics appear to have specific properties of action on small-intestinal reservoirs, constituting possible explanations for the empirically observed beneficial effects of anticholinergic treatment of functional disturbances after restorative proctocolectomy.

The effects of age, gender, and parity on rectoanal functions in adults

The effects of age, gender, and parity on rectoanal function were examined in a cross-sectional population study, including 68 normal subjects (32 men and 36 women) aged 23 to 91 years. Rectal volumetry was evaluated with graded isobaric rectal distension with 5-60 cm H2O in combination with anal manometry. Data were analysed by use of the multiple regression technique. Increasing age correlated with a decrease in rectal volume (r = -0.285, p less than 0.05), resting anal pressure (r = -0.625, p less than 0.001), and maximal squeezing pressure (r = -0.557, p less than 0.001). The decrease in maximal squeeze pressure with age was similar in men and women (approximately = 1% x year-1), although the median of maximal squeeze pressure in women was 58.3-75.7% of that in men (p less than 0.001). Nor was there a difference in resting anal pressure between men and women. An age-dependent increase was observed for the pressure threshold to produce an initial sensation of rectal filling and the rectoanal inhibition reflex (r = 0.446, p less than 0.001). The sensory threshold increased with age, but this was more pronounced in women. No effect of parity on rectoanal function could be demonstrated. However, this would best be investigated in a longitudinal population study. We believe that identification of causes for interindividual variation and regression analysis procedures will increase the discriminative accuracy of analysis of rectoanal function. The present study shows that several of the demonstrated age-related changes have a tendency to expose elderly subjects, particularly women, to the problems of incontinence.

A prospective randomized comparison of two different pelvic pouch designs

The clinical manovolumetric, and functional results of restorative proctocolectomy were studied in patients randomly allocated to construction of either a J-shaped pouch (n = 29) or a pouch fashioned by the folding technique used for the Kock continent ileostomy (K-pouch) (n = 26). A complete endoanal mucosectomy was performed, and the pouches were all constructed from 30-cm lengths of ileum. There were no deaths and no significant difference in postoperative morbidity. Anal pressures were equal in the two groups. The K-pouch expanded more favourably postoperatively, and its volume at 1 year was significantly greater than that of the J-pouch (355 +/- 71 ml (SD); range, 225-495, versus 264 +/- 81 ml; range, 75-440; p less than 0.001). The pouches had similar motility patterns and sensory pressure thresholds. Initially after closure of the loop ileostomy there was a tendency for better functional outcome in K-pouch patients. At 1 year the overall distribution of functional defects did not differ, and the defaecation frequency was about equal in the groups.

Manovolumetric and sensory characteristics of the ileoanal J pouch compared with healthy rectum

Pouch volume, motility, sensory function and integrated pouch-anal mechanisms during graded isobaric distension of the pouch were prospectively studied in 67 patients with a J pouch-anal anastomosis. The findings were related to functional outcome. Thirty-six normal controls were studied for comparison. In contrast with normal rectum, the ileal pouch exhibited pronounced motility, and pouch contractions were frequent even at a high distension pressure. The presence of high pressure motility was associated with a poor functional outcome. The threshold pressure and threshold volume for eliciting first sensation of filling and urge to defaecate were significantly higher in the ileal pouch. The pressure threshold levels were not related to the functional outcome. Sphincter inhibition on pouch distension reappeared in 25 per cent of the patients. The distension pressure required to elicit the inhibition was considerably higher than in the control subjects. The functional result was similar irrespective of whether sphincter inhibition was present or not. The motor and sensory function of this artificial setting appear to be controlled by nervous mechanisms that are different from those in the healthy anorectum.

Pouch size: the important functional determinant after restorative proctocolectomy

Sixty-seven patients with a J-shaped ileonanal pouch were studied over a 2-year period with regular recording of sphincter and pouch characteristics and analysis of their role in functional outcome. Although there was a 27 per cent permanent reduction in resting anal pressure (RAP) (P less than 0.001), two-thirds of the patients still had a RAP within the normal range. The mean(s.d.) pouch volume increased during the first year from 132(46) ml to 282(85) ml. RAP was not related to functional outcome and preoperative RAP was not predictive of subsequent function. Large pouch volume and compliance correlated with low defaecation frequency (range of r = 0.27-0.36; P less than 0.05) and good overall function (r = 0.37-0.56; P less than 0.01). The initial pouch volume was predictive of subsequent overall function. The ileal length used for pouch construction predicted subsequent pouch volume (r = 0.48; P less than 0.001) and to some extent functional outcome (r = 0.28-0.37; P less than 0.05). However, the studied variables accounted for only 21 per cent of the total variance of functional outcome.

Manovolumetric characteristics and functional results in three different pelvic pouch designs

Different pouch designs and techniques for the perineal approach have been on trial in an attempt to improve results after restorative proctocolectomy. The 1-year results of two currently advocated procedures, the J-pouch and the S-pouch, were compared with the results obtained in patients with a pelvic pouch fashioned according to the folding technique used for the Kock continent ileostomy, all pouches having been constructed from equal 30 cm lengths of ileum. The maximal volume of the S- and Kock pouches at one year was 420 ml (250-570) (median and (range] and 410 ml (244-490) respectively, while it was significantly less, 305 ml (200-445) in the J-pouch (p less than 0.05). The compliance of the J-pouches was also significantly lower at all distension pressures. The median day-time defaecation frequency was four and was equal in the three groups. Although there was a tendency towards a more favourable overall functional result with less soiling, and less need for night evacuations among patients with a Kock-folded pouch compared to the other pouch types these differences failed to reach statistical significance. The favourable properties of the Kock pouch, well-known also from the conteinent ileostomy and urostomy, suggest that its design should be considered an interesting alternative even for restorative proctocolectomy. These encouraging results have yet to be confirmed in a comparative randomized trial.

Rectal reservoir and sensory function studied by graded isobaric distension in normal man

The rectal expansion and concomitant sensory function on graded, isobaric, rectal distension within the interval 5-60 cm H2O was investigated in 36 healthy young volunteers. Anal pressure and electromyography (EMG) from the external anal sphincter were simultaneously recorded. Rectal distension caused an initial rapid expansion followed by transient, often repeated, reflex rectal contractions and a slow gradual increase of rectal volume. The maximal volume displaced by the first reflex rectal contraction was 18 (13) ml, which was less than 10% of the volume at 60 s. The pressure threshold for appreciation of rectal filling was 12 cm H2O (95% CL 5-15 cm H2O) and coincided with the threshold for rectoanal inhibition. Urge to defecate was experienced at 28 cm H2O (15-50 cm H2O) distension pressure, which was close to the threshold for maximal rectal contraction, also coinciding with the appearance of the external anal sphincter reflex. The interindividual variation of rectal volume on distension with defined pressures varied widely, indicating a considerable variation of rectal compliance in normal man. No correlation was found between rectal volume and sex or anthropometric variables. The relative variations in pressure thresholds for eliciting rectal sensation and rectoanal reflexes were less than the corresponding threshold volumes. It was concluded that the dynamic rectal response to distension reflects a well graded reflex adjustment ideal for a reservoir.

Does balloon dilatation and anal sphincter training improve ileoanal-pouch function?

Although patients' satisfaction may be high after restorative proctocolectomy the functional results are still far from perfect. Increased bowel frequency and imperfection in continence are common. Pouch volume and anal sphincter status are important determinants for the outcome. The aim of the present study was to evaluate if balloon dilatation of the pouch and sphincter biofeedback training might improve the results. Forty patients with an ileo-pouch anal anastomosis were randomized into a control and a treatment group. During the interval with a diverting ileostomy, patients in the latter group were subjected to balloon dilatation of the pouch and sphincter biofeedback training by using a manovolumetric technique. All patients were functionally assessed and anorectal manovolumetry performed preoperatively and at regular intervals postoperatively. Follow-up time was at least 12 months. Immediately before ileostomy take down patients in the treatment group showed a significant initial increase in pouch compliance compared with controls. However, a rapid and pronounced increase in pouch volume occurring after ileostomy closure in the control group equalized this initial difference. Anal resting tone and maximum squeezing capacity were at all intervals similar in the two groups. Bowel frequency per 24 h was similar and mucus soiling occurred to a similar extent in both groups, and the overall functional result as assessed according to a scoring system was equal at each interval. Balloon dilatation of the pouch and sphincter exercises appear not to be essential measures in these patients.

The functional results after colectomy and ileorectal anastomosis for severe constipation (Arbuthnot Lane's disease) as related to rectal sensory function

Rectoanal manovolumetry during graded isobaric rectal distension was carried out in 12 women with severe constipation classified as slow transit constipation (Arbuthnot Lane's disease). The resting anal sphincter pressure, the rectoanal inhibitory reflex and the rectal capacity were all normal. While the distension volumes required to elicit sensation of rectal filling and an urge to defaecate were within normal limits in all patients the distension pressures required to elicit such sensations fell outside the 95% limits of variation of control subjects in 4 patients. All patients were subsequently subjected to colectomy and ileorectal anastomosis. Patients with normal rectal sensory function had a satisfactory functional result after colectomy, whereas the four patients with blunted sensation did not improve. These findings suggest that rectoanal manovolumetry with determination of the distension pressures required to elicit rectal sensation is an important preoperative measure to be used in patients with severe constipation for selection of patients suitable for colectomy and ileorectal anastomosis.