What is obstructed defaecation?

Obstructed defaecation simply means having difficulty emptying the bowel. 

What causes obstructed defaecation?

There are two causes of obstructed defaecation, functional causes and physical causes. Sometimes the two can coexist. 

• Functional- in this situation the pelvic floor fails to relax or even tightens when a patient tries to open their bowel.  
• Physical causes- these are caused by weakness in the pelvic floor rectoceles, enteroceles and internal prolapse (intussusception). These cause either a physical blockage to evacuation, or result in a pocket forming which traps some bowel content meaning evacuation is incomplete. 

What symptoms do obstructed defaecation cause?

The symptoms experienced include some or all of the following: 

• Needing to strain 
• Never feeling empty 
• Frequent visits to the lavatory 
• Fruitless visits to the lavatory 
• Using a finger to help evacuation  

 As emptying may not be complete some patients describe leakage of a small amount of stool after they have been to the lavatory. 

How is obstructed defaecation investigated?

Before confirming the diagnosis and finding a cause for obstructed defaecation, patients will require some form of endoscopic examination of the bowel either by flexible sigmoidoscopy or colonoscopy to ensure that it is otherwise healthy. 

The most useful test to determine the cause of obstructed defaecation is an MRI proctogram or a  videoproctogram. These give information not only about structural problems but also whether or not the pelvic floor works properly. 

A transit study is often performed to establish whether the passage of bowel movements through the colon are delayed.  

Most patients will also have tests of their sphincter muscle function (anorectal physiology) and an endoanal ultrasound scan to look for any damage to the muscle. 

How is obstructed defaecation treated?

Keeping the stools soft, avoiding straining and the use of glycerine suppositories will help many patients.  

 The use of enemas and irrigation systems can be beneficial to enable patients to ‘wash out’ and empty the rectum.  

Where the problem is due to muscle function or disco-ordination then biofeedback / physiotherapy is usually recommended to enable patients to regain co-ordination of their pelvic floor.  

 If a physical cause for the symptoms is found surgical correction may be recommended. Such procedures might include rectocele repair, an enterocele repair or a rectopexy.