Obstructed defecation

Source: Wikipedia, the free encyclopedia.
Obstructed defecation syndrome
Other names
  • Functional obstructed defecation syndrome.[1]
  • Obstructed defecation.[2]
  • Obstructive defecation.[3]
  • Outlet obstruction.[4][note 1]
  • Anal outlet dysfunction.[1]
  • Rectal outlet obstruction.[5]
  • Anorectal outlet obstruction.[6]
  • Pelvic outlet obstruction.[7]
  • Outlet obstructive constipation.[8][note 2]
  • Outlet constipation.[9]
  • Pelvic constipation.[1]
  • Difficult evacuation.[1]
  • Obstructed evacuation.[10]
  • Evacuatory dysfunction.[7]
  • Rectal evacuatory dysfunction.[11]
  • Anorectal dysmotility.[6]
  • Dyschezia.[12]
  • Evacuation disorder.[9]
  • Fecal evacuation disorder.[13]
coloproctology

Obstructed defecation syndrome (abbreviated as ODS, with many synonymous terms) is a major cause of

bowel movements per week.[15] Normal definitions of functional constipation include infrequent bowel movements and hard stools. In contrast, ODS may occur with frequent bowel movements and even with soft stools,[16] and the colonic transit time may be normal (unlike slow transit constipation), but delayed in the rectum and sigmoid colon.[6]

Definitions and terminology

Definition and classification of constipation

Constipation is usually divided into two groups: primary and secondary.[17] Primary constipation is caused by disrupted regulation of neuromuscular function of in the colon and the rectum, and also disruption of brain–gut neuroenteric function.[17] Secondary constipation is caused by many other different factors such as diet, drugs, behavioral, endocrine, metabolic, neurological, and other disorders.[17] There are main subtypes of primary constipation which are recognized, although overlap exists (see: Co-existence of different constipation subtypes): dyssynergic defecation, slow transit constipation (colonic dysmotility) and irritable bowel syndrome with constipation.[17][6]

Definition and terminology of obstructed defecation syndrome

Obstructed defecation is one of the causes of chronic constipation.[18] ODS is a loose term,[16] consisting of a constellation of possible symptoms,[7] caused by multiple, complex[19] and poorly understood[20] disorders which may include both functional and organic disorders.[14] The topic of defecation disorders is very complicated, and there is a lot of confusion regarding terminology and classification in published literature.[9] Occasionally some sources[21] inappropriately treat ODS as a synonym of anismus.[9] Although anismus is a major cause of ODS, there are other possible causes.[15] Other authors use the term ODS to refer to defecatory dysfunction in the absence of any pathological findings (that is, a purely functional disorder).[22] Furthermore, many different terms have been used for ODS, which appear to refer to the same clinical entity. The term ODS does not appear in the ICD-11 and Rome-IV classifications, which both instead refer to "functional defecation disorders". One publication criticized such classifications as being ambiguous and based on symptoms rather than distinct etiopathological entities.[9] The authors suggested that "evacuation disorders" be used as a descriptive term, which would be subclassified to include all possible factors that may be contributory to the symptoms.[9]

In 2001, the American Society of Colon and Rectal Surgeons (ASCRS), the Colorectal Surgical Society of Australia, and the Association of Coloproctology of Great Britain and Ireland published a consensus statement which covered definitions relevant to this topic.[23] A revised consensus statement was published by the ASCRS in 2018.[15] Wherever possible, this article generally follows the definitions and terminology of the 2018 consensus statement,[note 3] wherein ODS is defined as "a subset of functional constipation in which patients report symptoms of incomplete rectal emptying with or without an actual reduction in the number of bowel movements per week."[15] Functional constipation is usually defined as infrequent bowel movements and hard stools. In contrast, ODS may occur with frequent bowel movements and even with soft stools,[16] and the colonic transit time may be normal (unlike slow transit constipation).[6]

Co-existence of different constipation subtypes

The ODS may or may not co-exist with other

functional bowel disorders, such as slow transit constipation or irritable bowel syndrome.[15]
Of all cases of primary constipation, it is reported that 58% are dyssynergic defecation, 47% are slow transit constipation and 58% are irritable bowel syndrome.[17] Significant overlap exists. For example, approximately 60% of patients with dyssynergic defecation also have STC.[17] In a study of 1,411 patients with chronic constipation referred to a tertiary center, 68% had normal transit constipation, 28% had evacuation disorders and less than 1% had slow transit constipation without any evacuation disorder.[17]

ICD-11

The term "obstructed defecation syndrome" does not appear in ICD-11. However, the following entries are present, as well as separate codes for most of the individual organic lesions listed in this article:

  • Functional anorectal disorders: "anorectal disorders which principally present anorectal and defecation complaints without apparent morphological changes of anorectal regions." A note is added: "However, the distinction between organic and functional anorectal disorders may be difficult to make in individual patients."[24]
  • Functional defecation disorders: this is listed as a sub-entry of functional anorectal disorders (above). It includes
    dyssynergic defecation (defined as "paradoxical contraction or inadequate relaxation of the pelvic floor muscles during attempted defecation"), and inadequate defecatory propulsion (defined as "inadequate propulsive forces during attempted defecation"). A note is added: "The patients must satisfy diagnostic criteria for functional constipation."[25]
  • Incomplete defecation: this entity (ME07.1) exists as a sub-code of fecal incontinence, with no definition.[26]

Rome-IV

The term "obstructed defecation syndrome" does not appear in the Rome IV classification. However, diagnostic criteria for functional defecation disorders are listed.[27] According to Rome-IV, this is defined as "features of impaired evacuation" during repeated attempts to defecate.[27] To qualify for this diagnosis, patients must meet the Rome diagnostic criteria for functional constipation or irritable bowel syndrome with constipation (IBS-C).[27] Furthermore, 2 of the following 3 tests must show abnormal results: balloon expulsion test, anorectal manometry or anal surface electromyography, or imaging (e.g. defecography).[27] Two subcategories exist within the functional defecation disorders category: Inadequate defecatory propulsive (F3a) and Dyssynergic defecation (F3b).[27] These are defined as "Inadequate propulsive forces as measured with manometry with or without inappropriate contraction of the anal sphincter and/or pelvic floor muscles",[27] and "Inappropriate contraction of the pelvic floor as measured with anal surface EMG or manometry with adequate propulsive forces during attempted defecation" respectively.[27] The subcategories F3a and F3b are defined by age- and gender-appropriate normal values for the technique.[27] For all of these Rome-IV diagnoses, diagnostic criteria must have been fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.[27]

Signs and symptoms

There is a constellation of possible symptoms.[7]

  • Straining,[19] and attempting to defecate for a long period of time.[28]
  • Inability to voluntarily empty the rectum.[29]
  • Use of, or dependence on, enemas and/or laxatives.[15]
  • Self-digitation.[19]
  • Posturing (the need to assume "unusual" posture).[30]
  • Frequent urge to defecate,[3] and frequent bowel movements/toilet visits,[31] where only fecal pellets may be passed.[16]
  • Conversely, there may reduced number of bowel movements per week.[15][1]
  • Abnormal stool texture, which may be anything from watery/loose (overflow diarrhea),[3] to fragmented,[19] very hard[15] or pellet-shaped.[3]
  • Actual or subjective sensation of incomplete evacuation.[32][19] even with soft stools.[33]
  • Unsuccessful attempts at bowel movements.[1]
  • Painful bowel movements.[1]
  • Tenesmus.[19]
  • Bowel urgency.[19][16]
  • Feeling of occupation or "mass" in the vagina.[33]
  • Pelvic heaviness.[19]
  • Pelvic pain[33] and cramping.[3]
  • Bloating.[1]
  • Fecal incontinence,[33] which may occur after defecation.[16]
  • Urinary incontinence.[33]
  • Poor appetite and early satiety when eating.[3]

rectal intussusception), internal/external anal sphincter dysfunction, or descending perineum syndrome.[7]

Self-digitation (digital help) is the use of the digits (fingers) to apply pressure in order to achieve defecation. Most people recognize the need for digitation as a symptom, and not a treatment.[16] Medical professionals generally do not recommend it, since it may lead to complications and is not very effective, only removing feces in the lower part of the rectum.[16] There are 3 methods: vaginal, perineal and rectal.[11] Gloves are used for hygiene.[16] Vaginal digitation is when the patient presses the posterior (back) wall of the vagina to support it, or to push the rectocele pouch from inside the vagina, which makes the anorectum straight and facilitates defecation.[19][16] "Milking" pressure can also be applied on the posterior vaginal wall.[16] Perineal digitation (also termed "splinting"),[28] is pushing on the perineum (or buttocks), which acts to stimulate the transverse muscles of the perineum causing a reflex rectal contraction of the rectum which helps to evacuate the feces.[19] Rectal digitation is when patients insert a finger into the anus to "hook" out fecal pellets,[16] or to apply pressure to the walls of the anus and/or the rectum, or to support an obstructing anatomical defects such as a sigmoidocele. Possible complications of rectal digitation are injury of the lining of the rectum,[16] such as ulcerations with bleeding and discomfort, and anal fibrosis leading to a stricture.[19]

Pathophysiology

Relevant anatomy and physiology

In order to understand ODS, it is necessary to understand the normal anatomy and defecation process.[3][6]

The pelvic floor (pelvic diaphragm) can be divided into 4 compartments: Anterior or urinary (bladder, bladder neck, and urethra), Middle or genital (vagina and uterus in women, prostate in men), Posterior (anus, anal canal, sigmoid, and rectum), and Peritoneal (endopelvic fascia and perineal membrane).[34]

Defecation is a complex physiologic process,[3] involving interaction between neural processes, reflexes, colorectal contractility and the biomechanics of straining.[16]

When feces reach the rectum, the rectal walls become naturally distended, stimulating nerve receptors. Brain centres for defecation respond to this sensation and stimulate mass colonic movement in the colon and the rectum.[16] These mass contractions move feces along the colon and into the rectum.[16] Occasionally some straining helps, which normally transmits forces to the upper part of the rectum, and aids defecation.[16] Reflexive relaxation of the external anal sphincter is also triggered.[33] For defecation to occur, rectal pressure must be greater than pressure in the anal canal, which depends on the relaxation of the external anal sphincter, the puborectalis and the intra-abdominal force applied.[33] In normal defecation, the pressure in the rectum increases at the same time as the pressure in the anal canal falls, leading to a propulsive rectoanal pressure gradient (RAG).[22]

According to some experts in ODS, defecation should normally occur once per day.[16] However many sources assert that it is medically "normal" for bowel movements to occur anywhere between three times per week up to three times per day.[35]

Pathophysiology

One review stated that the most common causes of disruption to the defecation cycle are associated with pregnancy and childbirth, gynaecological descent, or neurogenic disturbances of the brain-bowel axis.[36] Patients with obstructed defecation appear to have impaired pelvic floor function.[18]

Causes

Classification

ODS can be classified into four groups.[7]

ODS may also be associated with solitary rectal ulcer syndrome.[38]

Discussion of specific causes

Dyssynergic defecation (anismus)

Dyssynergic defecation (anismus) is defined as "failure of

puborectalis muscle and the external anal sphincter) to relax appropriately during attempted defecation".[15] In extreme cases, when defecation is attempted, the muscles may contract instead of relaxing (paradoxical contraction).[15] Dyssynergic defecation may occur in up to 40% of all patients with constipation.[1]

"Celes"

The suffix '-cele' is from ancient Greek, and means 'tumor', 'hernia', 'swelling', or 'cavity'. More modern translations are 'cystic cavity' or 'cystic protrusion'.

pouch of Douglas.[16] A sigmoidocele is a protrusion of the peritoneum between the rectum and vagina that contains a loop of the sigmoid colon.[15] An omentocele is a protrusion of the omentum between the rectum and the vagina.[15] These conditions can additionally be described as internal (when visible only on defecography) or as external (when there is a rectocele or rectal prolapse which is visible without imaging).[15] If these abnormalities do no reduce spontaneously, the term perineal hernia is used.[39]

A peritoneocele usually originates in the posterior compartment of the pelvis, or sometimes it can be located anteriorly (in front) or laterally (on the side) to the vagina. In severe cases, during defecation peritoneal contents can protrude through into the vagina or rectum, or displace them. Symptoms are variable, depending on the severity and the location of the herniation, and may include incomplete evacuation of the rectum, heavy sensation in the pelvis, and constipation.[39]

Enterocoele may develop because of weakening pelvic floor, multiple pregnancies, hysterectomy, and long term chronic straining. Sometimes people have a developmental condition where the rectovaginal septum fails to completely fuse, and they have a congenitally deep pouch of Douglas.[16]

Rectal hyposensitivity

Also termed "blunted rectum",

diabetes mellitus,[12] or by diseases which effect the central nervous system (the spinal cord or brain),[12] such as multiple sclerosis,[12] or Parkinson's disease.[40] Rectal hyposensitivity may also result from pelvic nerve injury (e.g. spinal trauma, pelvic surgery, anal surgery, hysterectomy or disc (L5-S1) surgery).[12][40] People with a history of severe sexual/physical abuse may have rectal hyposensitivity, theorized to reflect altered central processing of rectal sensation in response to painful rectal stimuli.[40] Rectal hyposensitivity is frequently associated with ODS, especially with dyssynergic defecation.[40] It is detected in about 23% of people with constipation overall.[40]

Psychological factors

Potential psychological factors which may contribute to ODS are

bulimia).[3] Many patients with ODS will report initiating stressful life events that worsened their constipation.[3] Such life stressors include new job, divorce, financial problems, sexual abuse or assault.[3]

Other neurological causes

Other neurological disorders may cause or contribute to ODS, such as

Hirschsprung disease,[12] Chagas disease,[12] and hereditary myopathy of the internal anal sphincter.[12]

Anal stenosis

Bowen disease, tuberculosis, actinomycosis, lymphogranuloma, anal and rectal cancers and developmental abnormalities of the anus.[17] Some authors describe a "muscular" type of anal stenosis (i.e. a functional disorder). Functional anal stenosis disappears under anesthesia, whereas true anal stenosis does not. The main symptoms of anal stenosis are difficult evacuation of stool, narrow stools, painful defecation, need for self-digitation to achieve defecation, bleeding from anal tears, and constipation.[17]

Diagnosis

Diagnosis is very challenging for clinicians, since most patients will simply complain of "constipation".[3] As discussed previously, there are many possible causes of ODS, which often may occur together in the same patient, and ODS may co-exist with other conditions such as slow-transit constipation.[3] As such, the first step in diagnosis is identification of organic causes of ODS and to identify possible slow transit constipation.[6] Also, patients may be too embarrassed to discuss their exact problems, especially with regards symptoms like digitation.[3]

The two key features of obstructed defecation are:

  1. An inability to voluntarily evacuate rectal contents.[29]
  2. Normal colonic transit time, but delayed transit in the rectum and sigmoid colon.[6]

Scoring systems

Scoring system are recommended in ODS to assess the severity of symptoms, to enable measurement of treatment outcomes, and to enable comparison of different treatment modalities in research. The Renzi ODS score is a five-item questionnaire. It has been validated for diagnosis and grading of ODS.[32] The parameters are:

  1. Excessive straining
  2. Incomplete rectal evacuation
  3. Use of
    laxatives
  4. Vaginal-anal-perineal digitations (needing to press in the back wall of the vagina or on the perineum to aid defecation)
  5. Abdominal discomfort and/or pain

Another validated instrument is the Altomare ODS score.[42] There are 7 parameters, scored from 0-4:

  1. Mean time spent at the toilet
  2. Number of attempts to defaecate per day
  3. Anal/vaginal digitation
  4. Use of laxatives
  5. Use of enemas
  6. Incomplete/fragmented defaecation
  7. Straining at defaecation
  8. Stool consistency

Investigations

There are many different investigations which are used in the diagnosis of ODS. Some authors state that multiple different diagnostic tests are required because of the coexistence of multiple causative factors.

digital rectal examination and anorectal manometry were shown to cause paradoxical sphincter contraction in healthy controls, who did not have constipation or incontinence.[43] Due to the invasive and perhaps uncomfortable nature of these investigations, the pelvic floor musculature is thought to behave differently than under normal circumstances. Therefore, paradoxical pelvic floor contraction is a common finding in healthy people as well as in people with chronic constipation and stool incontinence, and it may represent a non-specific finding or laboratory artifact related to untoward conditions during examination. They concluded that true anismus is actually rare.[43] Many of these tests assess simulated, rather than spontaneous, true defecation function.[9]

Specific investigations which have been used in ODS are:

Diagnostic approach for specific causes

Evacuation proctography

Evacuation proctography is the most common type of imaging used in the diagnosis of posterior pelvic floor disorders and ODS.

ionising radiation and is embarrassing and invasive for patients.[28]

Dyssynergic defecation

Dyssynergic defecation may be detected clinically, by

Valsalva manoeuvre or evacuation.[1] The diagnosis can be confirmed by anal electromyography, anorectal manometry, and/or defecography.[15]

"Celes"

It is difficult to tell peritoneocele, enterocele and sigmoidocele apart from rectocele without imaging. Peritoneocele is the most difficult type of pelvic prolapse to detect by clinical examination. To improve visualization of peritoneocele during MR defecography, the patient should complete normal defecation and the rectal contrast material should be completely evacuated, because then the rectovaginal space widens and pushes the peritoneum and bowel loops inferiorly (lower).[39]

An enterocoele can be easily detected by a clinician during physical examination. Using a bidigital technique (one finger in the anus and another in the vagina), the mass of the enterocele can be felt to "slip upwards" between the fingers when squeezing together. If the patient coughs during this procedure, it is easier to detect.[16]

Treatment

It is suggested that a multidisciplinary approach is the best way to treat ODS.

gastroenterologist and colorectal surgeon.[20] The general goal of treatment is to improve defecation mechanics and stool texture.[3] This will give marked improvement in quality of life for most patients with ODS.[3]

Conservative management versus surgery

Treatment may be conservative or surgical.[14] The exact way of managing ODS is controversial, with many authors now taking positions against surgery as a first line treatment for ODS, while others state that surgery should be used as a last resort,[6] not be used at all, or take a more pro-surgery position. Treating ODS can be extremely challenging and time-consuming.[3] It is rare that ODS is "cured" with one intervention or in a single setting.[3]

The underlying, original causes of ODS are typically psychological, muscular and/or neurological.[19] Such causes require complex, long term treatment.[19] Some authors have suggested that surgically correctable anatomical disorders which are detected in ODS patients may actually represent effects, rather than causes of ODS.[19] Furthermore, the complexity of this condition means it takes a lot of time to understand it.[16] However, both patients and surgeons prefer faster solutions like surgical procedures.[16] It has been suggested that this is the reason why most, if not all surgical procedures are unsuccessful in the long term.[19] In other words, the detectable anatomical defects can be restored surgically, but this does not mean that the function is also restored.[19] Others report that the outcomes of non-surgical methods have conflicting results, and their effects are not significant.[30]

Most authors now recommend a combination of different conservative measures.[14] If conservative fail to improve symptoms, management can be supported, where strictly indicated, with surgical procedures as a secondary treatment.[19][14] This approach reflects the multifactorial nature of ODS, where the exact approach to treatment is individualized to each patient. For example, in a patient with isolated dyssynergic defecation and no other anatomical defect, surgery is contraindicated, however where ODS is caused by a neoplastic tumor or external prolapse, surgery is usually strongly indicated.[6] Some stress that it is important for clinicians to set realistic and honest goals with patients.[3]

Overall it is reported that nearly 20% of patients need surgical treatment.[19] Surgery is said to be overused to treat ODS, with more than 50% of patients undergoing the stapled transanal rectal resection (STARR) procedure.[19] There are many different surgical treatments which have been attempted to treat ODS.[30] Some authors state that the vast number of reported surgical treatments that have been used for ODS indicate that surgery is an unsuccessful treatment for ODS.[citation needed]

European consensus guidelines on management

In 2021 a consensus regarding approach to treatment of ODS was published. A panel of 31 surgeons from 12 European countries worked on the consensus. The members of the panel were all engaged in research and treatment of ODS, and were considered expert in the field of pelvic floor functional disorders. They came to a consensus on about 50% of controversial issues surrounding management of ODS, which enabled creation of a treatment algorithm. The algorithm was based around the condition of the function of the anal sphincter, the presence of dyssynergia and the presence of other abnormalities like rectocele, intussusception, etc.[44]

They unanimously agreed that surgery should be discouraged for pelvic floor dyssynergia, and instead that biofeedback/pelvic floor retraining was the first line treatment. When dyssynergia is present with major abnormalities like rectocele or rectal intussusception, biofeedback/pelvic floor retraining should be conducted before attempting surgery.[44]

For patients with rectal intussusception and a large rectocele or enterocele the experts all preferred laparoscopic (transabdominal) ventral rectopexy with non resorbable mesh, regardless of the function of the sphincter. Especially in the case of poor sphincter function (e.g. some degree of fecal incontinence), they preferred to avoid transanal approach, because there is greater risk of further deterioration in continence function. In the event of failure of previous ventral rectopexy, the consensus was to repeat the same procedure again rather than carry out different procedures.[44]

For patients with large rectocele or enterocele only (i.e. no intussusception), there was no clear consensus about the best treatment. The experts did however agree that mesh should not be used for direct rectocele repair.[44]

Conservative (non-surgical)

Some authors state that treatment of ODS is mainly conservative.[19] Many such conservative (non surgical / medical) measures have been used to treat ODS:

Diet

Dietary measures are frequently used for ODS as the first line treatment.[3] The aim is to improve stool texture.[3] It has been recommended to avoid foods like chocolate, which increase stool viscosity, making it more difficult to pass stools.[19] Bulk-forming laxatives are also frequently used for ODS.[19]

It is recommended to increase dietary fiber intake to 25-30 grams daily. This may be slowly increased up to a level of 50 grams per day. This is usually achieved with high-fiber cereal and fiber powder supplements such as

wheat dextrin.[3]
However, fibre supplementation only fractionally increases gut transit and stool bulk.[11] The effect may take several weeks to become apparent.[11] Other authors report that a high fiber diet rarely helps ODS symptoms, and may make them worse.[6]

Patients with ODS are often advised to drink plenty of water.[19] 1-2 liters of water per day is recommended, especially in warmer climates or warmer weather.[3]

Biofeedback / Pelvic floor rehabilitation

Biofeedback is a learning strategy which is based on operant conditioning. The main goal is to improve abdominal and pelvic floor coordination. This is usually done by giving the patient visual or auditory feedback about muscular contraction during attempted defecation maneuvers, as well as verbal feedback about posture and diaphragmatic breathing.[6] Biofeedback can successfully treat abnormal contraction and relaxation of muscles in the anorectum during defecation.[20] This enables normal peristalsis instead of abnormal contraction and retrograde movement of bowel contents.[11]

Biofeedback is now one of the most popular treatments for ODS, particularly because it is safe.[6] It is most beneficial for patients with dyssynergic defecation.[11] It is also used for rectal hyposensation.[19] Rectocele and recto-rectal intussusception can sometimes be treated by pelvic floor rehabilitation alone,[19] as long as they have not been present for a long time.[19] Larger and more significant examples of these organic/anatomical disorders require surgery to correct since they because contributing causes to ODS by themselves.[19] Regardless, this treatment seems to be beneficial both for patients with mild symptoms, and for those with severe symptoms which are unresponsive to other conservative measures and who are being considered for surgery.[11]

Biofeedback has been shown to improve symptoms (improved frequency of bowel movements, reduced straining) and also reduce need for laxatives,[11] and patients stop needing to self-digitate.[20] Researchers demonstrated that patients who had positive results with biofeedback had evidence of improved autonomic innervation of the colon, increased colonic transit time, and had increased quality of life scores.[11] Overall, biofeedback is reported to have about 70% success rate for pelvic floor dyssynergia (dyssynergic defecation).[29] The success of biofeedback for patients with ODS caused by mechanical defects is not well known.[29]

For patients who do not undergo biofeedback, simple pelvic floor and abdominal muscle relaxation exercises may also be useful to make evacuation easier.[19]

Psychotherapy / Psychological counselling

Psychological counselling is indicated for people with ODS and depression and/or anxiety.[19] Psychological techniques (guided imagery and relaxation) have been combined with ultrasound-guided biofeedback.[19] This "psycho-echo-biofeedback" approach was reported to be successful for 50% of patients after 2 years.[19]

Irrigation

Variously termed hydrocolontherapy,[19] lavage,[19] retrograde large bowel irrigation,[19] and rectal irrigation. This refers to the use of water to wash out the rectum. Usually this is done with warm water (or normal saline),[30] administered via a tube inserted into the anus.[19] Some authors report this treatment as effective and safe with no risk of side effects.[19] Self-administered enemas may however be abused, which can cause anorectal fibrosis and stricture, due to repeated microtrauma.[19] The disadvantages of this treatment are mainly social stigma and inconvenience. The water and stool may take some time to fully evacuate, especially with patients with obstructed defecation. People with reduced muscular strength of the anal sphincter may encounter problems with later leakage of the water mixed with stool, which may bring similar, socially devastating problems as seen with fecal incontinence. Overall this treatment may be dissatisfying to patients because of difficulty with cohabitation, travel, and work/study or leisure activities.

Transanal electrostimulation

Transanal electrostimulation is carried out at home with an anal probe and an electrostimulator.[19] It is a treatment for pudendal nerve neuropathy and rectal hyposensation.[19] Another new treatment combines biofeedback with transanal electrostimulation.[30]

Botox injections

Injection of 50-60 units of

puborectalis muscle has been reported for anismus,[19] and ODS.[3] The botulinum toxin is injected under ultrasound guidance into two sites on both sides of the puborectalis muscle.[3] This procedure itself could be considered as minor surgery, although in the studies reporting this technique, patients were not sedated or given local anesthetic.[3] Short term cure rate was approximately 50%.[19] Another study reported 79% of patients had improved symptoms, and had broadening of the anorectal angle demonstrated on defecography.[3] Side effects are transient anal incontinence and hypotension.[19] The effects of Botox only last for about 3 months, meaning the procedure may only be temporary and it may have to be repeated.[3]

Other measures

Anismus has been reported to be treated with yoga exercises.[19]

Surgical

Surgical procedures can be considered in three groups: transvaginal, transabdominal and transanal; or as either manual techniques or stapling procedures. No surgical procedure has been demonstrated to be the best, and each has advantages and disadvantages.[30] There are no widely accepted selection criteria for these surgical procedures.[30]

Partial division of puborectalis muscle

This transanal manual procedure aims to relax the tension of a hypertrophic (overdeveloped) puborectalis muscle.[30] The partial division can be done laterally (on one side) or at the posterior midline (in the middle at the back of the muscle).[30] There are some positive reports of this proceudre, which was said to be more effective compared to non surgical treatments such as biofeedback and botulinom toxin A injections.[30] However other reports state that this method is disappointing, failing to improve ODS symptoms for most patients.[30] There is a high risk of fecal incontinence after this surgery and it is generally no longer recommended.[45]

Ventral mesh rectopexy

Ventral mesh rectopexy has become popular for rectal prolapse, internal rectal prolapse and ODS, especially in Europe.

laparoscopically.[49] The procedure reduces constipation and fecal incontinence in patients with rectal prolapse or rectal intussusception, and has a low rate of complications and recurrence.[49] The procedure is able to correct multiple anatomical defects associated with vaginal and rectal prolapse, as well as improving function in terms of continence and defecation.[47]

Prognosis

ODS generally has a benign prognosis, however it is a distressing condition for patients.[44] The condition may severely reduce quality of life,[44] both socially and psychologically,[30] and also reduce sexual well-being.[28] Symptoms persist for some patients despite conservative treatment,[14] and dissatisfactory outcomes are frequently reported after surgery.[44]

Epidemiology

Constipation as a general complaint is very common. The ODS subtype is also known to be a common problem,[1] but the exact reported epidemiological figures vary.[12] It is estimated that approximately a third of patients complaining of constipation have the ODS subtype, which is more than slow transit constipation.[12] Some reported or estimated figures include:

  • 7% of adults.[33]
  • 10–20% of adults.[2]
  • 12–19% of North Americans.[1]
  • Up to 30% of the population.[12]

The prevalence is greater in older people of both sexes, especially women. Overall, most patients with ODS are females.

nulliparous females (i.e. have never given birth).[2]

Notes

  1. ^ "Outlet obstruction" may also refer to disorders of the bladder (bladder outlet obstruction) or the stomach (gastric outlet obstruction).
  2. ^ "Outlet obstructive constipation" (OOC) appears to be the standardized term used in Chinese publications.
  3. ^ With the exception of substitution of the term "anismus", which is used in the ASCRS consensus statement. Many publications instead use the term "dyssynergic defecation", notably ICD-11 and Rome-IV. Some authors have expressed disapproval of the continuned use of the term "anismus".

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