Background: In patients with IBS, many symptoms have their origin in the recto-anal segment, with motility changes in the rectum and in the internal anal sphincter, and alterations in rectal sensitivity. However, up to now, it is not known if these clinical and physiological changes are equated with morphological changes in the recto-anal segment.
Methods: Sixteen consecutive patients with IBS (mean age 22, range 18-33 years; 13 females) and 10 healthy volunteers (mean age 34.5, range 19-50 yr.; 6 males) were evaluated prospectively with defaecography.
Results: 1) Anorectal angle: No significant differences were observed in the anorectal angle during rest (91.6 +/- 3.5 degrees vs 92.6 +/- 2.5 degrees) and during defaecation (92 +/- 5.5 degrees vs 98.7 +/- 2.6 degrees) between patients with IBS and healthy volunteers. However, patients with IBS were unable to widen the angle during defaecation, remaining the same at rest (91.6 +/- 3.5 degrees) as during defaecation (92 +/- 5.5 degrees). IBS patients with constipation (n = 2) compared to those with normal frequency defaecation (n = 13) showed no significant differences at rest (95 +/- 6 vs 89.8 +/- 4.1 degrees) and during defaecation (100 +/- vs 88.9 +/- 6.4 degrees). Healthy volunteers widened the angle by more than 5 degrees during defaecation. 2) Perineometry: although not significant, patients with IBS had less perineal descent during the simulated defaecation (1.98 +/- 0.37 cm) than healthy subjects (2.1 +/- 0.3 cm). Nevertheless, during squeeze there was significantly less mobility or perineal descent in patients with IBS than in control subjects (0.21 +/- 0.17 vs 0.95 +/- 0.21 cm; P = 0.01).
Conclusions: The findings of this study suggest that patients with IBS as a whole, whether constipation predominant or not, showed changes in pelvic-floor mobility.