Normal values and pressure morphology for three-dimensional high-resolution anorectal manometry of asymptomatic adults: a study in 110 subjects

The purpose of this study is to evaluate normal values and pressure morphology of three-dimensional high-resolution anorectal manometry (3D-HRM) in asymptomatic volunteers and to determine the relationship between objective measurable values, gender, and age. Anorectal pressures and rectal sensation were evaluated in 110 asymptomatic volunteers (46 females and 64 males) ranging in age from 18 to 80 years (median age, 52 years) in left lateral position by three-dimensional high-resolution manometry. Maximum squeeze pressure, residual anal pressure, and intrarectal pressure were significantly higher in males compared to females (p < 0.05 each). Duration of sustained squeeze was significantly lower in males compared to females (p < 0.05). Maximum resting pressure, mean resting pressure, and maximum squeeze pressure were inversely correlated (r = -0.310, p < 0.01, r = -0.276, p < 0.01, and r = -0.198, p < 0.05) with age. The value of rectoanal pressure differential was -13.1 +/- 5.8 mmHg which was negative during defecation. Overall variation coefficient in anorectal pressures ranged between 0.21 and 0.34. This study establishes normal values for anorectal pressure by 3D-HRM in asymptomatic volunteers. There are significant gender differences concerning squeeze patterns. Increasing age is associated with lower maximum resting pressure, mean resting pressure, and maximum squeeze pressure. Normal characteristic pressure morphology of anorectum can be obtained at rest, during squeeze, and bear down as in defecation by 3D-HRM.