Rectal anatomy after rectopexy: cinedefecography versus MR-defecography.

BACKGROUND

Conventional defecography can reveal abnormalities in patients with evacuatory disorders. With fast dynamic MR imaging systems, MR-defecography has become possible, which does not expose patients to ionizing radiation. The purpose of this study was to assess the correlation of both methods after rectopexy.

MATERIALS AND METHODS

Twenty-one consecutive patients underwent abdominal sigmoidectomy and rectopexy due to evacuatory disorders. Postoperatively, all patients were investigated by cineradiographic defecography. Fourteen patients underwent MR-defecography additionally. The results were screened for anorectal angle and pelvic floor position (rest, squeezing, and evacuation). The findings were depicted in Box plot analysis and compared with the Friedman-test. Descent of pelvic organs was also assessed.

RESULTS

In MR-defecography, anorectal angle at rest was smaller than in conventional defecography, but there was no difference during squeezing and defecation. Concerning pelvic floor position, during squeezing, MR-defecography illustrated a lower perineum and a broader range of pelvic settings, but no difference at rest and during evacuation. In four patients, MR-defecography visualized a descent of the bladder. However, in four patients with complete evacuation in cineradiography and with no clinical complaints about incomplete evacuation, MR imaging showed deficient evacuation. Overall continence of patients was significantly improved through surgery, but there was no change in sphincter pressure, radial asymmetry, or sphincter length.

CONCLUSIONS

In general, with respect to anorectal angle and perineal motility, both methods revealed consistent results. The concomitant depiction of structures in MR-defecography is helpful in the assessment of descent of pelvic organs and permits visualization of enteroceles. However, in 30% of patients, MR-defecography wrongly showed incomplete evacuation.