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

Abstract

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.

The influence of prostatectomy and body position on location and displacement of pelvic landmarks with pelvic floor muscle contraction

“…Lower UVJ position in standing after surgery infers less support rather than lengthened puborectalis muscle, similar to the explanation provided above. This does not depend on surgical disruption of passive supports as a similar observation was made preoperatively with a change in body position 14 . In contrast, greater cranial UVJ displacement after surgery was not observed preoperatively 14 .…”

“…The change in MU and BP location to be more ventral in standing than sitting after surgery (but not preoperatively 14 ) could be explained by surgical changes to urethral anatomy such as the dissection of the puboprostatic ligaments and endopelvic fascia 9 which would affect the ventral support of the urethra and demonstrate different orientation to the pubic symphysis as pelvic tilt changes between body positions 26 …”

“…14 In contrast, greater cranial UVJ displacement after surgery was not observed preoperatively. 14 This implies disruption of passive supports might enable greater bladder mobility, but not greater descent.…”

“…This does not depend on surgical disruption of passive supports as a similar observation was made preoperatively with a change in body position. 14 In contrast, greater cranial UVJ displacement after surgery was not observed preoperatively. 14 This implies disruption of passive supports might enable greater bladder mobility, but not greater descent.…”

“…Recent work using TPUS has shown that position and displacement (with contraction) of pelvic landmarks associated with PFM contraction differs between sitting and standing. In standing, the puborectalis muscle length is shorter at rest (presumably related to greater activation necessary to support pelvic contents) and PFM landmark motion associated with SUS and puborectalis shortening is greater relative to sitting 14 . As prostatectomy impacts the passive support of the pelvic structures, urethral length, and anatomy and function of PFM, standing is likely to present a unique challenge in these men.…”