High-Resolution Anorectal Manometry and Balloon Expulsion Test Outcomes in Functional Constipation: A Comparative Study.

BACKGROUND Functional constipation can occur in children and adults and consists of difficult or infrequent bowel movements, painful defecation, or the sensation of incomplete bowel movement, and it can be idiopathic. This study aimed to compare the findings from high-resolution anorectal manometry (HRAM) and the balloon expulsion test (BET) in 360 patients with functional constipation and 73 healthy volunteers. MATERIAL AND METHODS In total, 360 patients with functional constipation and 73 healthy volunteers underwent HRAM and BET in our hospital from January 2017 to December 2023. We collected the general data of all participants and surveyed the defecation symptoms of patients with functional constipation. RESULTS Our study showed no significant correlation between HRAM results and age in healthy volunteers, while men had a higher residual anal pressure (P=0.022), higher anal squeeze pressure (P=0.020), and lower rectoanal pressure gradient than women (P=0.017). Using logistic regression analysis, it was concluded that sex (OR=2.880, 95% CI [1.654,5.015], P=0.000) and sensation of incomplete evacuation (OR=1.892, 95% CI [1.023,3.500], P=0.042) affected the occurrence of dyssynergic defecation. The specificity of BET in diagnosing dyssynergic defecation was 81.89%, while that of HRAM was 52.78%. CONCLUSIONS This observation provides normal values for anorectal pressures by HRAM. HRAM and BET are effective methods for assessing functional constipation. Being male and having sensation of incomplete evacuation are risk factors for dyssynergic defecation. The specificity of BET for diagnosing dyssynergic defecation was higher than that of HRAM.