Obstructive Defecation Syndrome

Obstruction means a blockage. Defecation is a medical term for passing out stool.

The last part of the large intestine is called as rectum. It ends at the anus. It temporarily stores feces before being expelled out of body. Inability to pass stools through the digestive tract, out of the rectum is called Obstructive Defecation Syndrome (ODS). In this condition, even if one has frequent visits to the toilet, one is not able to empty the rectum.

Rectum in obstructive defecation syndrome

Causes of ODS

There are several reasons for causing obstruction in the passage of stools, which can be because of one or more of the following listed causes:


As age advances, muscles become weak. This is applicable for pelvic (hip) muscles too. A weakness in muscles of hip, is also seen in women who gave birth to more than two children. This can lead to a prolapse (protrusion) of rectum. Its called as a rectocele.

  • Rectal Intussuception

    Internal rectal prolapse (rectal intussusception) can block the bowel lumen (passage of faeces). This often occurs with a rectocele.

  • A Tightness in Hip Muscles

    This is due to overcontraction of these muscles. This can make the patient to have frequent urination, constipation, straining, pain during or after passing stools.

  • Chronic Constipation

    Problems with digestive tract can also cause long term constipation. Impacted (pressed firmly together) stool can itself cause ODS.

Symptoms of ODS

The most common symtoms exerienced by ODS patients are listed below:

  • Frequent urination
  • Not able to pass stools freely. So one might spend more time in the toilet.
  • Too much strain while passing stool.
  • One can feel a block or incomplete emptying of stool. This can make you to use your finger and manually assist to evacuate the feces.

Diagnosing ODS

History and Physical Examination

A detailed physical examination can give clues for your doctor to know the cause. Symptoms like recent changes in bowel habit or rectal bleeding must be excluded. Pelvic floor muscle problems are diagnosed by specially trained doctors. They might use manual techniques to check the function of these muscles. Its called as Digital Rectal Examination.


Sigmoidoscopy may be needed to view the sigmoid colon.

Colonoscopy can be done to view the entire colon and look for abnormalities.

A defecogram is very helpful for those who have difficulty passing stools. Its an xray with barium contrast use. It enables us to see the structures in your lower abdomen, and the way they move when you try to empty your bowel.

Anal Manometry

Anal manometry and endoanal ultrasound can be useful tests. It can determine how well the muscles around the anus are working. It also differentiates a weak vs tight pelvic floor.


Electromyography (EMG) records the electrical activity produced by skeletal muscles. This test can show the weakness in the muscles in the hip and the muscles around the anus.

Treatments for ODS


Pelvic floor physiotherapy is the mainstay treatment. When your pelvic floor muscles are tight and weak, the tension should be treated before the weakness.Pelvic floor retraining can be done to make the muscles reach a normal resting tone. Afterwhich they will be able to relax fully. They gain back their strength by doing pelvic floor strengthening exercises.

Surgical Treatments

  • STARR (Stapled Transanal Resection of the Rectum) – If one has intussusception or a rectocele a STARR can fix it. Once the procedure is done patients can go home on the following day.
  • Laparoscopic ventral rectopexy, is suitable for women with a visible external rectal prolapse and ODS.


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Dr. J. S. Rajkumar


M.S., F.I.C.S., Dip. N.B. (SURG.), F.R.C.S. (ENG.), F.R.C.S. (EDIN.), F.R.C.S. (GLASGOW), F.R.C.S. (IRELAND), F.I.M.S., F.A.I.S., F.R.M.S. (LONDON), F.A.E. (GASTRO), F.A.C.G. (USA), F.I.C.A. (USA), F.I.A.G.E.S., Dip M.I.S. (FR.)

Dr. S. Akbar