We wanted to evaluate whether both the colonic transit time (CTT) and defecography are necessary for diagnosing constipated patients, and we also wanted to assess the defecographic findings of patients with outlet obstruction on CTT.

Over the recent 3 years, 26 patients (21 women and 5 men, mean age: 59 years) underwent both CTT and defecography because of their chronic constipation or defecation difficulty. The mean interval between the 2 studies was 48 days. Colonoscopy, barium enema and manometry were performed in 22, 8 and all the patients, respectively.

On CTT, 13 patients (50.0%) were normal and 13 patients (50.0%) were abnormal; the abnormal results were composed of outlet obstruction (n=8, 30.8%), outlet obstruction and colon inertia (n=2, 7.7%), colon inertia (n=2, 7.7%), and outlet obstruction and hindgut dysfunction (n=1, 3.8%). On defecography, 6 patients (23.1%) were normal and 20 patients (76.9%) were abnormal; the results were composed of rectocele (n=8, 30.7%), rectocele and perineal descent syndrome (PDS; n=4, 15.4%), PDS and rectal intussusception (n=3, 11.5%), spastic pelvic floor syndrome (SPFS; n=3, 11.5%), rectocele and SPFS (n=1, 3.8%), and rectal intussusception (n=1, 3.8%). Of the 11 patients with outlet obstruction on CTT, rectocele (n=4, 36.4%), SPFS (n=1, 9.1%), rectocele and PDS (n=1, 9.1%), and PDS and rectal intussusception (n=1, 9.1%) were demonstrated on defecography, except for the 4 normal cases.

Both CTT and defecography were necessary for diagnosing the patients with chronic constipation in compensation, and 63.6% of the patients with pelvic outlet obstruction showed an abnormal pelvic defecation function.