Anal Sphincter Injury

What is a sphincter injury?

A sphincter injury refers to a tear or damage to the muscle that surrounds the anal canal.  The anal sphincter muscle consists of two muscles;  the internal sphincter and the external sphincter muscle.  These muscles are used to control bowel movements.   Damage to one or both of these muscles can result in the decreased ability to control bowel movements and can contribute to symptoms of accidental bowel leakage.


What causes a sphincter injury?

Sphincter injuries can occur as a result of anal or rectal surgery, obstetrical trauma or other trauma to the rectum.  Obstetrical trauma can include tears, episiotomies or the use of vacuum or forceps with delivery.


How is a sphincter injury diagnosed?

Patients should undergo a thorough history and physical exam.  History taking will focus on obstetrical history, previous anorectal surgeries, other trauma to the anal canal, and current bowel habits including the ability to control gas and stool.  Physical exam includes thorough inspection of the anus with digital exam by a specialized physician such as a Colon and Rectal surgeon.  Other tests that may be performed are anal manometry to measure the pressures of the anal canal and endoanal ultrasound to visualize the internal and external anal sphincter muscles or an MRI. 


How is a sphincter injury treated?

Treatment options for sphincter injuries for patients who are experiencing accidental bowel leakage include surgical repair of the anal sphincter muscle and biofeedback therapy.  Surgical repair of the sphincter muscle involves an operation performed under general anesthetic at the hospital.  Biofeedback therapy is a treatment used to help strengthen the muscles of the anus and pelvic floor to decrease incidents of accidental bowel leakage.  Sacral nerve stimulation is another treatment option available for persistent symptoms of accidental bowel leakage.  In the past there have been different versions of an artificial bowel sphincter to treat sphincter injuries, however there are none currently on the market.