Anorectal 3D manometry (3D HRAM) is the most advanced version of manometric equipment that measures pressures along the anal canal in a very detailed manner. It provides complete data about pressure profile of anorectum and may indicate impaired defecation dynamics. Balloon expulsion test (BET) is a cheap, easy way to diagnose constipation as the result of outlet obstruction.

Our aim is to compare this two methods of diagnosis of dyssynergic defecation and to find the correlation between this diagnostic equipment.

Patients with the diagnosis of constipation will be enrolled in the study. Each patient will be investigated by anorectal manometry and after the procedure BET will be performed at the same day.

During anorectal manometry conventional manometric parameters will be recorded, such as resting pressure, squeeze pressure, bear down manoeuver, thresholds of sensation and threshold of recto anal inhibitory reflex. 3D picture of anal canal will be recorded.

After the manometry standard BET will be performed. The balloon will be inserted into the rectum and patient will be asked to expel it in private during 1 min.

Data from manometry will be correlated with the success rate of BET.

Inclusion Criteria:

• Constipation
• Parental agreement

Exclusion Criteria:

• after surgery on lower gastrointestinal tract
• diagnosis of inflammatory bowel disease
• diagnosis of other disorder that may affect anorectum function
• parental disagreement