A fundamental examination for the diagnosis
of anorectal disorders
The anal sphincters
The anal sphincters are ring-like muscles located around the anus that control the opening and closing of the anal canal and are responsible for the continence of fecal material inside it. These important muscles work together by contracting and relaxing to maintain continence and allow defecation when necessary. The anal sphincters can be divided into:
- Internal anal sphincter: a smooth, involuntary muscle that remains normally contracted to maintain fecal continence. It automatically relaxes when stool enters the rectum, signaling the need to go to the bathroom.
- External anal sphincter: a striated, voluntary muscle that provides additional control over defecation. It can be voluntarily contracted to hold stool until an appropriate time to defecate is found.
For various reasons (childbirth, constipation, aging, or various injuries), one or both of these muscles can weaken or become damaged. In such cases, it is crucial to identify the specific cause of their malfunction to determine the most appropriate treatment. One of the main tests aimed at assessing the health of the anal sphincters is anorectal manometry.
What is anorectal manometry?
Anorectal manometry is a diagnostic test used to evaluate the functionality of the anal sphincters and the nerves of the pelvic floor. It is an important test for diagnosing various anorectal disorders, such as fecal incontinence, chronic constipation, and other pelvic floor dysfunctions. The test is performed using a device called a manometer, consisting of a flexible catheter equipped with ultrasensitive sensors. These sensors measure the pressure exerted by the muscles of the anus and rectum during contraction and relaxation. The pressure variations are recorded and analyzed to assess muscle functionality and the coordination between the internal and external anal sphincter muscles and the puborectalis muscle. The results of anorectal manometry, combined with other diagnostic tests and clinical evaluation, provide a comprehensive understanding of the patient’s disorders, helping to improve the quality of life for individuals with anorectal dysfunctions.
Clinical contexts
Anorectal manometry is indicated in various clinical contexts to study, diagnose, or exclude proctological conditions such as:
- Fecal incontinence
- Chronic constipation
- Anal fissures
- Anal fistulas
- Hemorrhoids
- Anorectal pain
- Pelvic floor disorders.
How anorectal manometry is performed
Anorectal manometry is a safe, outpatient procedure lasting about 15-30 minutes. The patient is placed in a supine position, and after applying a lubricant with an anesthetic effect, the manometric catheter is gently inserted into the anus until the sensors are correctly positioned. During the test, the patient may be asked to perform some maneuvers, such as contracting the anal muscles, pushing, relaxing, and coughing, to evaluate muscle response and pressure variations. Additionally, a small balloon is inflated with air at the tip of the catheter to simulate the volume of the fecal bolus, allowing the responses of the rectum and anus to this stimulus to be analyzed.
The parameters evaluated during the test include:
- Basal tone: evaluation of anal pressure at rest.
- Pushing force: evaluation of pressures in the anal canal during maximal voluntary contraction and maximal straining.
- Rectal sensitivity to distension and recto-anal inhibitory reflex: evaluation of sensitivity by recording the volume of balloon distension in the rectum at which the first sensation is felt, its duration, and the corresponding urgency stimulus.
- Rectal compliance: measurement of rectal pressure during its gradual distension.
Through the study of the results, the proctologist can direct the patient towards specific therapies or interventions for the identified problems.
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.