To investigate rectal sensitivity and associated factors in patients with different subtypes of functional defecation disorder (FDD).

We segregated individuals diagnosed with FDD into two groups based on their defecation patterns: those with dyssynergic defecation and those with inadequate defecatory propulsion. We gathered general information through questionnaires and assessed rectal sensitivity using anorectal manometry. The rectal sensitivity performances of the two groups were compared; the factors related to rectal sensitivity were analyzed to determine the factors associated with rectal sensitivity, and the effect of biofeedback therapy on rectal sensitivity was clarified.

Rectal sensitivity in different subtypes of FDD decreased, and the difference between the two groups was not statistically significant (P > 0.05). There were no statistically significant differences in the first constant sensation volume, defecatory desire volume, and maximum tolerable volume between the different subtypes of FDD (P > 0.05). Multi-factor binary logistic regression analysis showed that age, constipation symptom score, and diabetes were all independent risk factors for decreased rectal sensitivity (P < 0.05). There were no statistically significant differences between the prior- and post-biofeedback therapy in the first constant sensation volume, defecatory desire volume, and maximum tolerable volume (P > 0.05).

Rectal sensitivity in different subtypes of FDD decreased. Age, constipation symptom score, and diabetes were independent risk factors for decreased rectal sensitivity. Short-term biofeedback therapy did not improve rectal hyposensitivity in patients with FDD.