Defecation is a complex process that requires the correct coordination of the bowel, rectum, anal canal and pelvic floor muscles. When this balance is disrupted, bowel movements may become too rapid or, conversely, difficult and incomplete. In the latter case, this may be referred to as Obstructed Defecation Syndrome (ODS), a condition characterised by difficulty passing stools despite the urge to defecate. It is not simply a matter of “not going to the toilet often enough”: people affected may feel the need to defecate without being able to complete the evacuation, or may be required to strain excessively and for prolonged periods, making defecation a difficult and often frustrating experience.
What are the symptoms of obstructed defecation?
One of the most characteristic symptoms of Obstructed Defecation Syndrome (ODS) is the sensation of incomplete evacuation, often associated with the need for excessive or prolonged straining, meaning intense abdominal effort to facilitate the passage of stools. Other symptoms may include:
- a sensation of blockage or obstruction in the anorectal area;
- a persistent feeling of needing to defecate even after a bowel movement;
- the need to have several bowel movements during the day;
- the frequent need to use laxatives, enemas or suppositories;
- the need to use digital vaginal or perineal manoeuvres to facilitate the passage of stools;
- the onset of a sensation of heaviness or pressure in the anal area, which in more severe cases may become painful.
Why does it occur?
Obstructed defecation may be associated with a number of causes, mainly anatomical or functional:
- ANATOMICAL: difficulty with evacuation may be caused by structural abnormalities, including internal rectal prolapse, rectocele, enterocele and descending perineum syndrome. In the first case, the rectal wall tends to fold in on itself, obstructing the passage of stools. A rectocele, which is more common in women, consists of a bulging of the rectum towards the vagina, creating a sort of “pouch” in which stools may become trapped. An enterocele may compress the rectum, while excessive descent of the pelvic floor may alter the normal mechanics of defecation.
- FUNCTIONAL: in other cases, the problem is related to impaired coordination of the pelvic floor muscles. During normal defecation, contraction of the abdominal muscles increases the pressure needed to expel stools, while the pelvic floor and anal canal muscles must relax to allow their passage. When this coordination is impaired, the muscles may fail to relax adequately or may even contract, hindering rather than facilitating evacuation. This condition is known as pelvic floor dyssynergia or dyssynergic defecation.
The diagnostic pathway
The diagnostic pathway begins with a proctological examination, together with a careful assessment of symptoms and of the way in which evacuation takes place. Depending on the clinical picture, the specialist may recommend further investigations to assess the structure and function of the anorectal area and pelvic floor, as well as to rule out any organic conditions that may cause similar symptoms, such as colorectal cancer, acute diverticulitis or chronic inflammatory bowel disease.
The tests and assessments most commonly used by the proctologist include:
- Digital rectal examination: this allows the clinician to directly assess for a possible rectocele, mucosal prolapse or abnormal pelvic floor muscle tone.
- Colonoscopy or rectoscopy: these may be recommended to rule out the presence of organic, inflammatory or neoplastic conditions responsible for the symptoms.
- Defecography or dynamic Magnetic Resonance Imaging (MR defecography): these allow the clinician to observe what happens during evacuation and to identify any anatomical or functional abnormalities.
- Anorectal manometry: assesses the pressures and coordination of the muscles involved in defecation,
Balloon expulsion test, assesses the patient’s ability to expel a small balloon from the rectum within a set period of time.
What treatment options are available?
Treatment for obstructed defecation is tailored according to the underlying cause and the characteristics of the individual patient. In all cases, the first step includes lifestyle advice, with particular attention to a balanced diet, an adequate fibre intake and good hydration, all of which are essential to help achieve a stool consistency that is easier to pass.
When the condition is related to pelvic floor dyssynergia, treatment is mainly rehabilitative. Through physiotherapy, targeted exercises and biofeedback techniques, the patient learns to recognise and correctly coordinate the muscles involved in defecation and to relax the pelvic floor at the appropriate time.
When an anatomical cause is present, such as internal rectal prolapse or a rectocele, and conservative treatment is not sufficient, an integrated approach based on the combination of surgery and physiotherapy may be indicated. Surgery, when necessary, aims to correct the structural abnormality, while rehabilitation helps restore proper pelvic floor function and improve the mechanics of defecation. The choice of treatment is assessed by the specialist on the basis of the type of abnormality, the severity of symptoms and the results of diagnostic investigations.
❗The contents of this page are for informational purposes only and should in no way replace the advice, diagnosis, or treatment prescribed by your physician. Responses to the same treatment may vary from patient to patient. Always consult your doctor regarding any information related to diagnoses and treatments, and meticulously follow their instructions.
