Defecation proctography and translabial ultrasound in the investigation of defecatory disorders.

OBJECTIVES

Defecation proctography is the standard method used in the investigation of obstructed defecation. Translabial ultrasound has recently been shown to demonstrate rectocele, enterocele and rectal intussusception. We performed a comparative clinical study to determine agreement between the two methods.

METHODS

Thirty-seven women scheduled to undergo defecation proctography for obstructed defecation were recruited. Using both proctography and translabial ultrasound, we determined the anorectal angle, presence of a rectocele and rectocele depth, rectal intussusception and prolapse. Measurements were obtained by operators blinded to all other data. All patients rated discomfort on a scale of 0-10.

RESULTS

Six women did not attend defecation proctography, leaving 31 cases for comparison. The mean age was 53 years. Patients rated discomfort at a median of 1 (range 0-10) for ultrasound and 7 (range 0-10) for defecation proctography (P < 0.001). Defecation proctography suggested rectocele and rectal intussusception/prolapse more frequently than did ultrasound. While the positive predictive value of ultrasound (considering defecation proctography to be the definitive test) was 0.82 for rectocele and 0.88 for intussusception/prolapse, negative predictive values were only 0.43 and 0.27, respectively. Cohen's kappa values were 0.26 and 0.09, respectively. There was poor agreement between ultrasound and defecation proctography measurements of anorectal angle and rectocele depth.

CONCLUSIONS

Translabial ultrasound can be used in the initial investigation of defecatory disorders. It is better tolerated than defecation proctography and also yields information on the lower urinary tract, pelvic organ prolapse and levator ani. Agreement between ultrasound and defecation proctography in the measurement of quantitative parameters was poor, but when intussusception or rectocele was diagnosed on ultrasound these results were highly predictive of findings on defecation proctography.