Influence of body position on dynamics of the pelvic floor measured with transperineal ultrasound imaging in men.

Aims: This paper aims to evaluate the feasibility of transperineal ultrasound imaging (TPUS) for visualizing the motion of pelvic landmarks associated with striated pelvic floor muscle contraction in men in standing; to compare the locations of pelvic landmarks between sitting and standing; and to compare the effects of different body positions on measures of pelvic floor muscle contraction.

Methods: Thirty-five men awaiting prostatectomy volunteered to participate. Participants performed three repetitions of submaximal pelvic floor contraction in sitting and again in standing. Movement of pelvic landmarks with contraction was recorded using an ultrasound imaging transducer placed on the perineum.

Results: The feasibility of TPUS in men in standing was demonstrated through the visualization of three out of four pelvic landmarks in more than 95% of images in the standing position. Analysis of pelvic landmarks and their respective relationships with muscle shortening demonstrated that the anorectal junction and urethrovesical junction were lower and the estimated length of puborectalis was shorter in standing than sitting. The mid-urethra (striated urethral sphincter) and anorectal junction (puborectalis) landmark displaced further cranially in standing than sitting.

Conclusions: TPUS can be used to visualize three pelvic landmarks in men with cancerous prostates. Puborectalis is shorter at rest in standing than sitting, and elevation of the mid-urethra and the anorectal junction is more in standing than sitting. Together these findings indicate that feedback for pelvic floor muscle training is possible in both positions, but the position needs to be standardized for a comparative assessment.