The pharmacology of the internal anal sphincter and new treatments of ano-rectal disorders

Surgical options for faecal incontinence in the presence of intact sphincters are limited. Furthermore, in patients with fissures, lateral sphincterotomy reduces anal sphincter hypertonia but there has been concern about complications. A greater understanding of the basic pharmacology of the internal anal sphincter has led to the development of novel treatments for both these disorders. A Medline review was undertaken for internal anal sphincter pharmacology, anal fissures and faecal incontinence. This review is based on these articles and those found by further cross-referencing. Nitric oxide released from non-adrenergic non-cholinergic nerves is the main inhibitory agent in the internal anal sphincter. Relaxations are also mediated through beta-adrenoceptors and muscarinic receptors. Stimulation of alpha-receptors results in contraction. Calcium and its entry through L-type calcium channels is important for the maintenance of tone. Nitric oxide donors produce reductions in resting anal tone and heal fissures but are associated with side-effects. Muscarinic agents and calcium channel antagonists show promise as low side-effect alternatives. Botulinum toxin appears more efficacious than other agents in healing fissures. To date, alpha-receptor agonists have been disappointing at improving incontinence. Further understanding of the pharmacology of the internal anal sphincter may permit the development of new agents to selectively target the tissue with greater efficacy and fewer side-effects.     

Faecal incontinence in the elderly : epidemiology and management

Faecal incontinence occurs in up to 10% of community dwelling persons > or = 65 years of age and approximately 50% of nursing home residents. It is a vastly under-reported problem that has a devastating effect on those who experience it as well as their spouses and caregivers. There are three broad categories of faecal incontinence among the elderly: (i) overflow incontinence; (ii) reservoir incontinence; and (iii) rectosphincteric incontinence. The first two can be diagnosed based upon the patient's history and physical examination and the response to dietary and pharmacological interventions. The third is assessed by careful physical examination supplemented by diagnostic tests directed towards evaluation of anorectal continence mechanisms. The most important of these is anorectal manometry, which can be supplemented by studies of structure (anal ultrasonography or pelvic floor magnetic resonance imaging) and neuromuscular function (electromyogram). A variety of therapeutic interventions are employed in patients with rectosphincteric incontinence; these include dietary, behavioural, pharmacological and surgical modalities chosen on the basis of the results of diagnostic testing. For isolated internal anal sphincter weakness, a cotton barrier in the anal canal is often effective. Acute sphincter injury is best treated with sphincteroplasty but, otherwise, surgical procedures are of uncertain benefit. Peripheral neurogenic incontinence may be treated with antidiarrhoeal agents, biofeedback techniques and dietary manipulations. Sacral spinal nerve stimulation is a promising new technique for selected patients with neurogenic faecal incontinence and is currently undergoing testing in the US and Europe. Significant improvement in quality of life can be achieved in most elderly persons with faecal incontinence.     

Elastomer implants in faecal incontinence: a blind, randomized placebo-controlled study

AIM: To test efficacy and safety of polydimethylsiloxane elastomer implants, a silicone biomaterial, in patients with severe faecal incontinence related to an impaired internal anal sphincter. METHODS: Subjects were randomized to receive three injections of 2.5 mL of either physiological saline or polydimethylsiloxane elastomer. After local anaesthesia, an 18 gauge, 2.5-in needle was inserted through the perianal skin and laid down into the intersphincteric space. Treatment (saline or polydimethylsiloxane elastomer) was administered by means of a ratchet gun. Three injections of 2.5 mL each were performed in the area of the internal anal sphincter at 3, 7 and 11 o'clock positions. Main end point was the percentage of subjects in each treatment arm experiencing a successful treatment, defined as a Cleveland Clinic Florida-Faecal Incontinence score <8, 3 months after treatment. Secondary end points were quality of life scores, weekly number of faecal incontinence episodes, subject acceptance and adverse events rate. Both patients and end point assessments were blinded to treatment. Results: 44 women (64.3 +/- 9 years) with a baseline Cleveland Clinic Florida-Faecal Incontinence score > or =8 were enrolled prospectively; 22 received polydimethylsiloxane elastomer and 22 saline treatment. Treatment was well tolerated. At 3 months, the percentage of subjects experiencing a successful treatment was not different between polydimethylsiloxane elastomer and saline groups (23% vs. 27%, respectively, P = 0.73). Moreover, Cleveland Clinic Florida-Faecal Incontinence score was not significantly different between polydimethylsiloxane elastomer and saline groups (11.7 +/- 4.7 vs. 11.4 +/- 4.5, respectively, P = 0.79). CONCLUSIONS: Polydimethylsiloxane elastomer implants cannot be recommended for treatment of severe faecal incontinence related to impaired internal anal sphincter.     

Investigation of the distribution and function of ��-adrenoceptors in the sheep isolated internal anal sphincter

BACKGROUND AND PURPOSE

We have investigated the distribution of α-adrenoceptors in sheep internal anal sphincter (IAS), as a model for the human tissue, and evaluated various imidazoline derivatives for potential treatment of faecal incontinence.

EXPERIMENTAL APPROACH

Saturation and competition binding with ³H-prazosin and ³H-RX821002 were used to confirm the presence and density of α-adrenoceptors in sheep IAS, and the affinity of imidazoline compounds at these receptors. A combination of in vitro receptor autoradiography and immunohistochemistry was used to investigate the regional distribution of binding sites. Contractile activity of imidazoline-based compounds on sheep IAS was assessed by isometric tension recording.

KEY RESULTS

Saturation binding confirmed the presence of both α₁- and α₂-adrenoceptors, and subsequent characterization with sub-type-selective agents, identified them as α_1A- and α_2D-adrenoceptor sub-types. Autoradiographic studies with ³H-prazosin showed a positive association of α₁-adrenoceptors with immunohistochemically identified smooth muscle fibres. Anti-α₁-adrenoceptor immunohistochemistry revealed similar distributions of the receptor in sheep and human IAS. The imidazoline compounds caused concentration-dependent contractions of the anal sphincter, but the maximum responses were less than those elicited by l-erythro-methoxamine, a standard non-imidazoline α₁-adrenoceptor agonist. Prazosin (selective α₁-adrenoceptor antagonist) significantly reduced the magnitude of contraction to l-erythro-methoxamine at the highest concentration used. Both prazosin and RX811059 (a selective α₂-adrenoceptor antagonist) reduced the potency (pEC₅₀) of clonidine.

CONCLUSIONS AND IMPLICATIONS

This study shows that both α₁- and α₂-adrenoceptors are expressed in the sheep IAS, and contribute (perhaps synergistically) to contractions elicited by various imidazoline derivatives. These agents may prove useful in the treatment of faecal incontinence.     

Lack of effficacy of botulinum toxin in chronic anal fissure

BACKGROUND AND AIM: Hypertonicity of internal anal sphincter plays a major role in the persistence of chronic anal fissure. Botulinum toxin could induce internal anal sphincter relaxation without the adverse effects of surgery (long-term faecal incontinence) or topical nitrates (anal burning, headaches, hypotension). METHODS: We conducted a placebo-controlled, randomised, double-blind study to assess the efficacy of a single injection of botulinum toxin in the internal anal sphincter of patients with chronic anal fissure in six ambulatory care clinics. Eligibility criteria included a mean value of post-defecation anal pain >or= 30 mm on a 100 mm visual analogue scale over the week preceding inclusion. Main endpoint was the proportion of patients with symptomatic improvement during the fourth week after inclusion (post-defecation anal pain below 10 mm). RESULTS: Forty-four patients (22 in each group) were included. At inclusion, there was no significant difference between groups on age, sex ratio, pain duration, post-defecation anal pain, analgesic consumption and stool frequency. Ten (45%) and 11 (50%) patients reported symptomatic improvement on the main endpoint (P=0.76) in placebo and botulinum toxin groups, respectively. Ten patients (five in each group) had healed fissure at week 4 and ten patients (five in each group) required surgical treatment between weeks 4 and 12. Similarly, there was no significant difference between groups on other variables between weeks 4 and 12. CONCLUSIONS: The efficacy of a single injection of botulinum toxin in the internal anal sphincter does not differ from that of a placebo in patients with chronic anal fissure.     

Cost–effectiveness analysis of sacral neuromodulation (SNM) with Interstim for fecal incontinence patients in Spain

ABSTRACT

Introduction: Fecal incontinence (FI) is a condition with a high impact on the psychological and social life of healthy people. Interstim, the sacral neuromodulation (SNM) therapy, has shown higher effectiveness and safety rates than surgical procedures like dynamic graciloplasty or artificial anal sphincter in patients with intact anal sphincter (IAS) and after sphincteroplasty in patients with structurally deficient anal sphincter (SDAS).

Objective: To assess the cost-effectiveness of FI management in two scenarios – with and without SNM – and to estimate the potential budget impact of its progressive introduction in the Spanish setting.

Methods: Two decision analytical models were developed (IAS and SDAS patients) representing the possible clinical paths for each of the scenarios (with and without SNM), as well as its clinical and economic consequences in the mid-to long term with a Markov model. Clinical and resource use data were retrieved from the literature and validated by a clinician expert panel. Effectiveness was measured with both QALYs and symptom-free years (SFY). A 3% discount rate was used for future costs and benefits (time horizon = 5 years). Prevalence figures were combined with Interstim sales forecasts to estimate the total number of patients to receive therapy over the next 5 years and the associated budget impact.

Results: The introduction of Interstim in the therapeutic management of FI has an associated cost-effectiveness of €16?181 (IAS patients) and €22?195 (SDAS patients) per QALY gained. The progressive introduction of Interstim in 75 to 100 patients/year will have an estimated budget impact of 0.1% of incremental costs in patients with FI.

Conclusions: Introducing Interstim in the management of FI in IAS and SDAS patients in the Spanish setting has shown to be an efficient measure with an incremental cost–effectiveness ratio below the accepted Spanish threshold (around €35?000/QALY), and with a relatively low additional cost for the Spanish NHS.     

Preliminary evaluation of an injectable anal sphincter bulking agent (Durasphere) in the management of faecal incontinence

BACKGROUND: It has been previously shown that 'bulking' of internal anal sphincter defects may provide an effective method to treat patients with faecal incontinence, but the benefit wears off with time. AIM: To assess the efficacy of a larger molecule, bulking agent (Durasphere) over the short- and long-term in patients with an internal anal sphincter defect refractory to conservative management. PATIENTS: Eighteen patients (nine male, nine female) with a mean age of 60 years were recruited. All patients had persistent faecal leakage/soiling. METHODS: Durasphere was injected in the submucosal plane to restore anal canal symmetry. All patients had anorectal physiology, endoanal ultrasound, continence grading, patient satisfaction and quality of life scores assessed at 1, 3, 6 and 12 months. RESULTS: The mean follow-up is 28.5 months. Changes from baseline were not statistically significant up to 6 months. At 12 months there was significant improvement in the continence grading (P=0.003), patient satisfaction (P=0.053) and all quality of life subscales: lifestyle (P=0.004), coping (P=0.011), depression (P=0.024) and embarrassment (P=0.059). Anorectal physiological parameters apart from the maximum tolerable rectal volume at 12 months (P=0.036) showed no significant improvement. CONCLUSIONS: Anal sphincter bulking with Durasphere is safe and effective in the short term as well as the longer term. More importantly, there is no evidence of attenuation of effect over time.     

The relaxing effect of caerulein on isolated human internal anal sphincter

In the attempt to find a pharmacological treatment for the spasm of the internal anal sphincter, usually associated with anal fissures, the activity of caerulein on human internal and sphincter was investigated in vitro and in vivo. In the isolated distal part of the internal and sphincter, caerulein (0.61 microM) depressed resting muscle tone and caused marked relaxation of norepinephrine-contracted preparations. The effect of caerulein was reduced by atropine and increased by physostigmine, suggesting that it was largely due to the release of acetylcholine. In vivo, intravenous infusion of caerulein, both to healthy volunteers and to subjects affected by anal fissures and anal sphincter hypertone, did not modify the values of internal anal sphincter pressure. The lack of spasmolytic effect of caerulein in vivo may have been due to the relatively unimportant influence of cholinergic neurons on the control of internal anal sphincter tone. Alternatively, the presence of fibrosis caused by anal fissures could hinder sphincter relaxation.     

The effects of clonidine on symptoms and anorectal sensorimotor function in women with faecal incontinence

Aliment Pharmacol Ther 2010; 32: 681–688

Summary

Background Women with faecal incontinence and rectal urgency have increased rectal stiffness and sensation. Aim To evaluate the effects of clonidine, an α₂‐adrenergic agonist, in faecal incontinence. Methods In this open‐label uncontrolled study, bowel symptoms and anorectal functions (anal pressures, rectal compliance, and sensation) were assessed before and during treatment with transdermal clonidine (0.2 mg daily, 4 weeks) in 12 women with urge‐predominant faecal incontinence. Results Clonidine reduced the frequency (17.8 ± 3.1 before vs. 8.8 ± 3.9 after, P = 0.03) and number of days with faecal incontinence (11.8 ± 1.6 before vs. 6.1 ± 1.8 after, P = 0.02), faecal incontinence symptom severity score (max = 13, 8.3 ± 0.7 vs. 5.6 ± 0.9, P < 0.01), and allowed patients to defer defecation for a longer duration (P = 0.03). Although overall effects on anorectal functions were not significant, the treatment‐associated reduction in faecal incontinence episodes was associated with increased rectal compliance (r = ?0.58, P < 0.05) and reduced rectal sensation. (r = ?0.73, P = 0.007 vs. desire to defecate pressure threshold). Conclusions Clonidine improves symptoms in women with faecal incontinence; this improvement is associated with increased rectal compliance and reduced rectal sensitivity. A controlled study is necessary to confirm these observations.

     

一期切除保留括约肌直肠减压治疗高位复杂性肛瘘应用研究

目的 研究高位复杂性肛痿一期切除保留括约肌直肠减压术的方法,评价疗效和价值。方法 回顾性研究1986年1月至1997年1月38例高位复杂性肛瘘病例,一期切除全部外口、瘘管、内口,保留括约肌重叠修补,内口逐层缝合伤口,直肠减压。结果 本组病例全部愈合,无肛门失禁、肛门狭窄,术后复发及伤口不愈合等并发症发生。结论本术式治疗高位复杂性肛瘘简单、安全、有效,无并发症、后遗症,值得推广。     

Gastrointestinal smooth muscles and sphincters spasms: treatment with botulinum neurotoxin

More than fifty years following the discovery that botulinum neurotoxins inhibit neuromuscular transmission, these powerful poisons have become drugs with many indications. First used to treat strabismus, local injections of botulinum neurotoxin are now considered a safe and efficacious treatment for neurological and non-neurological conditions. One of the most recent achievements in the field is the observation that botulinum neurotoxin is a treatment for diseases of the gastrointestinal tract. Botulinum neurotoxin is not only potent in blocking skeletal neuromuscular transmission, but also block cholinergic nerve endings in the autonomic nervous system. The capability to inhibit contraction of smooth muscles of the gastrointestinal tract was first suggested based on in vitro observations and later demonstrated in vivo; it has also been shown that botulinum neurotoxin does not block non adrenergic non cholinergic responses mediated by nitric oxide. This has further promoted the interest to use botulinum neurotoxin as a treatment for overactive smooth muscles and sphincters, such as the lower esophageal sphincter to treat esophageal achalasia, or the internal anal sphincter to treat anal fissure. Information on the anatomical and functional organization of innervation of the gastrointestinal tract is a prerequisite to understand many features of botulinum neurotoxin action on the gut and the effects of injections placed into specific sphincters. This review presents current data on the use of botulinum neurotoxin to treat diseases of the gastrointestinal tract and summarizes recent knowledge on the pathogenesis of disorders of the gut due to a dysfunction of the enteric nervous system.     

Characterization of the alpha1-adrenoceptor subtype mediating contractions of the pig internal anal sphincter

BACKGROUND AND PURPOSE: The internal anal sphincter has been shown to contract in response to alpha1-adrenoceptor stimulation and therefore alpha1-adrenoceptor agonists may be useful in treating faecal incontinence. This study characterizes the alpha1-adrenoceptor subtype responsible for mediating contraction of the internal anal sphincter of the pig. EXPERIMENTAL APPROACH: The potency of agonists and the affinities of several receptor subtype selective antagonists were determined on smooth muscle strips for the pig internal anal sphincter. Cumulative concentration-response curves were performed using phenylephrine and noradrenaline. KEY RESULTS: The potency of the alpha1A-adrenoceptor selective agonist A61603 (pEC50=7.79+/-0.04) was 158-fold greater than that for noradrenaline (pEC50=5.59+/-0.02). Phenylephrine (pEC50=5.99+/-0.05) was 2.5-fold more potent than noradrenaline. The alpha1D-adrenoceptor selective antagonist BMY7378 caused rightward shifts of the concentration-response curves to phenylephrine and noradrenaline, yielding low affinity estimates of 6.59+/-0.15 and 6.33+/-0.13, respectively. Relatively high affinity estimates were obtained for the alpha1A-adrenoceptor selective antagonists, RS100329 (9.01+/-0.14 and 9.06+/-0.22 with phenylephrine and noradrenaline, respectively) and 5-methylurapidil (8.51+/-0.10 and 8.31+/-0.10, respectively). Prazosin antagonized responses of the sphincter to phenylephrine and noradrenaline, yielding mean affinity estimates of 8.58+/-0.10 and 8.15+/-0.08, respectively. The Schild slope for prazosin with phenylephrine was equal to unity (1.01+/-0.24), however the Schild slope using noradrenaline was significantly less than unity (0.50+/-0.11, P<0.05). CONCLUSION AND IMPLICATIONS: The results suggest that contraction of circular smooth muscle from the pig internal anal sphincter is mediated via a population of adrenoceptors with the pharmacological characteristics of the alpha1A/L-adrenoceptor, most probably the alpha1L-adrenoceptor form of this receptor.     

Review: loperamide—a potent antidiarrhoeal drug with actions along the alimentary tract

The synthetic opioid, loperamide, reduces stool weight, frequency of bowel movements, urgency and faecal incontinence in acute and chronic diarrhoea. In man, the mechanism of action of loperamide is primarily the retardation of small-intestinal transit, and the stimulation of anal sphincter pressure and of faecal continence. This mechanism increases mucosal contact time, allowing more complete absorption of electrolytes and water. Studies in animals have demonstrated inhibitory effects of opiates and opioids, including loperamide, on fluid and electrolyte secretion induced by various secretagogues. By comparison, opiates have smaller if any antisecretory or pro-absorptive actions in man. The discrepancies between the results obtained in animal and human experiments are most certainly due to the large differences between drug doses used. Besides its opiate-receptor binding and stimulating activity, loperamide also behaves as a calcium-calmodulin antagonist and as a calcium channel blocker. These two other mechanisms might contribute to loperamide's antidiarrhoeal activity. Loperamide is more effective and safer than other opiates or opioid drugs in the treatment of both infantile and adult diarrhoea of various causes, although adequate fluid and electrolyte replacement remain the prime need.     

Local renin–angiotensin systems in the genitourinary tract

Local renin–angiotensin systems are common throughout the human body. Recent evidence supports the existence of such local renin–angiotensin systems in the penis, clitoris, bladder, ureter, internal anal sphincter, and urethral sphincter. Beyond its role in regulating blood pressure through its effects on vascular tone, sodium balance, and fluid homeostasis, angiotensin II serves a key role in affecting physiologic and pathophysiologic activities of the genitourinary tract. Just as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are used for the treatment and prevention of heart disease and vascular disease, inhibition of excessive angiotensin II activity may be potentially useful for the treatment of urologic disorders.     

Effects of cisapride on ano-rectal sphincter function

To investigate the effects of cisapride, a motility-inducing agent, on ano-rectal sphincter functions, standard manometry was performed in 10 healthy male volunteers after 5 days on a 20-mg dose of cisapride in a placebo-controlled double-blind randomized crossover fashion. All subjects kept stool diaries during the experiment. Cisapride significantly increased stool frequency by adding soft and liquid stools; in addition, anal resting pressure was reduced with cisapride in seven of the 10 subjects; mean resting pressure decreased by 16%, while all other measurements were not altered. This suggests that cisapride may act directly on the smooth muscle of the internal anal sphincter. It also supports the view that enhanced defaecation in chronic constipation induced by cisapride may not be achieved by propulsive motor activity in the colon but also by a decreased anal sphincter tone.     

A new questionnaire for constipation and faecal incontinence

BACKGROUND: The prevalence, severity and risk factors of faecal incontinence in women in the community are incompletely characterized. AIM: To develop and validate a self-report questionnaire (faecal incontinence and constipation assessment) to address these issues. METHOD: Eighty-three women completed the instrument; 20 randomly selected patients answered the faecal incontinence and constipation assessment again 6 weeks later. A gastroenterologist also completed the faecal incontinence and constipation assessment in all 83 subjects after a detailed clinical assessment. Concurrent validity was evaluated by comparing the patient's self-report to a doctor interview for every question. Reproducibility was evaluated by a test-retest approach for every question. The severity of faecal incontinence was rated by incorporating the frequency and type of faecal incontinence, rectal urgency and use of sanitary devices. RESULTS: The questionnaire was well-understood. Reproducibility [median kappa statistic, 0.80 (interquartile range: 0.66-0.90)]; and concurrent validity [0.59 (0.47-0.67)] were acceptable. For the index question on faecal incontinence, the kappa for reproducibility and concurrent validity was 0.90 and 0.95, respectively. The faecal incontinence severity score was also valid (kappa = 0.5). CONCLUSION: The faecal incontinence and constipation assessment has excellent reproducibility and reasonable validity for assessing the presence, risk factors and severity of faecal incontinence and associated bowel disorders in women when compared against clinical assessment.     

Systematic review: the treatment of anal fissure

BACKGROUND: Anal fissure is one of the most common anorectal conditions encountered in clinical practice. Most patients experience anal pain with defecation and minor bright red rectal bleeding, allowing a focused history to direct the evaluation. METHODS: A systematic medical literature search of NIH, Pubmed, and MEDLINE using the search terms anal fissure, sphincterotomy, anal surgery and anal fissure medical therapy. English language was not a restriction. Cited references were used to find additional studies. RESULTS: No single treatment is the best choice for all patients. Because pharmacological therapy is not associated with permanent alterations in continence, a trial of either a topical sphincter relaxant or botulin toxin injection, along with adequate fluid and fibre intake, is a reasonable option. However, because pharmacological therapy has lower healing and higher relapse rates, surgery can be offered in the first instance to patients without incontinence risk factors who have severe, unrelenting pain and are willing to accept a small risk of incontinence, for the highest likelihood of prompt healing and the lowest risk of recurrence. CONCLUSIONS: Both non-operative and operative approaches currently exist for the management of anal fissure. Improved non-surgical therapies may continue to lessen the role of sphincter-dividing surgery in future.     

Pharmacological characterization of neurogenic responses of the sheep isolated internal anal sphincter

The aim of the study was to establish the nature of the neurogenic responses of the sheep isolated anal sphincter. Isolated strips of sheep internal anal sphincter develop intrinsic contractile tone following the application of stretch tension. On transmural stimulation (1 - 20 Hz, 10 V pulse strength, 0.5 ms pulse width, 1 s every 180 s) transient relaxations were observed. The amplitude of the relaxations were frequency-dependent reaching a maximal response at 10 - 20 Hz and were inhibited by tetrodotoxin (0.3 microM). Neither atropine (0.3 microM) nor phentolamine (1 microM) affected control responses. The nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 100 microM) and the selective inhibitor of soluble guanylyl cyclase ODQ, (1H-[1,2, 4]oxadiazolo[4,3-a]quinoxalin-1-one) (1 microM) completely inhibited the neurogenic relaxations and uncovered contractions that were abolished by 1 microM phentolamine and 0.1 microM prazosin. The effect of L-NAME, but not that of ODQ, was partially reversed by the addition of L-arginine (1 mM). Sodium nitroprusside (10 nM - 10 microM) caused concentration-dependent inhibition of myogenic tone and this effect was significantly reduced by ODQ. Calcium-free Krebs-Henseleit solution also reduced myogenic tone by 85%. Transmural electrical stimulation of the sheep isolated internal anal sphincter causes a transient relaxation of myogenic tone that appears to involve nitric oxide from non-adrenergic, non-cholinergic nerves and, to a lesser degree, noradrenaline from sympathetic nerves. The characteristics of the preparation compares well with that of human tissue and may prove to be a suitable animal based model for further studies.     

Anal sphincter biofeedback and pelvic floor exercises for faecal incontinence in adults--a systematic review

BACKGROUND: Faecal incontinence is a common health care problem. Biofeedback is extensively used in clinical practice to treat faecal incontinence. AIM: To systematically review and evaluate the evidence from clinical studies on the effectiveness of biofeedback as a treatment for faecal incontinence in adults. METHODS: A systematic literature search was undertaken using electronic databases, with review of the retrieved references. RESULTS: The search identified 46 studies published in English using biofeedback to treat adults complaining of faecal incontinence. Those studies included a total of 1364 patients. Of those studies with adequate data, 275 out of 566 patients (49%) were said to be cured of symptoms of faecal incontinence following biofeedback therapy and 617 out of 861 (72%) patients were reported to be cured or improved. Studies varied in the method of biofeedback used, criteria for success and the outcome measures used. Only eight of the 46 studies employed any form of control group. CONCLUSIONS: The data suggest that biofeedback and exercises help a majority of patients with faecal incontinence. However, methodological variation, lack of controls and a lack of validated outcome measures are problems in evaluating these results.     

Fecal incontinence: a clinical approach

"Fecal incontinence" is defined as the involuntary loss of stool at any time of life after toilet training. It is a socially and psychologically devastating condition for patients and their families, and a topic which both patients and physicians are reluctant to approach. Although the true prevalence of fecal incontinence is unknown, studies have reported it to be as high as 2. 2% in the general population, with significantly higher rates among nursing home residents and hospitalized elderly. Risk factors include advancing age, female gender and multiparity. An understanding of pelvic floor anatomy and physiology is required to appreciate how diverse medical conditions can affect mechanisms involved in normal continence. The rectum serves as a storage reservoir until elimination can take place at a socially acceptable time and place. The pelvic floor muscles help to regulate the defecatory process and maintain continence. These muscles include the internal anal sphincter, the external anal sphincter and the puborectalis muscle. Each muscle contributes to normal continence, although the relative importance of each is controversial. Neurologic integrity and sensation are also key factors. Conditions associated with fecal incontinence include diarrheal states, fecal impaction, idiopathic neurologic injury, surgical and obstetric injury, pelvic trauma, collagen vascular disease, and neurologic impairment related to stroke, diabetes, or multiple sclerosis. Evaluation of the patient with fecal incontinence includes a directed history and physical examination, with particular attention paid to integrity of the perineum and rectum, and a complete neurologic evaluation. Diagnostic tools such as stool studies, anorectal manometry, defecography, electromyography, pudendal nerve conduction, and endoanal ultrasound may be employed in an outpatient setting. Fecal incontinence may be treated conservatively by employing such methods as dietary restriction, stool bulking agents, and biofeedback. Surgery may be the best option for cases refractory to medical treatment, or for those patients with rectocele or obstetrical injury. In this article, we review the presentation, epidemiology, pathophysiology, and etiology of fecal incontinence. Evaluation, including key components of directed history and physical examination, and the appropriate use of diagnostic studies and indications for treatment options are also addressed.