Presentation Authors: Sean F. Mungovan*, Westmead, Australia, Petra L. Graham, Sydney, Australia, Daniel I. Vukovic, Christopher S. Han, Henk B. Luiting, Westmead, Australia, Jaspreet S. Sandhu, Oguz Akin, Sigrid V. Carlsson, James A. Eastham, New York, NY, Manish I. Patel, Westmead, Australia
Introduction: Pelvic floor muscle exercise (PFM) training programs are undertaken prior to radical prostatectomy (RP) to facilitate improved continence recovery. Preoperative membranous urethral length (MUL) is also measured preoperatively as an important patient anatomical factor that contributes to the time to achieve continence following RP. The structure and function of the MUL is inherently associated with the urethral sphincter complex since it is surrounded along its entire length by the rhabdosphincter. The functionality of the rhabdosphincter has an important role in continence, contributing to urethral closure pressures. Dynamic features of the shortening of the rhabdosphincter and specific training strategies are included in preoperative PFM training programs. Voluntary rhabdosphincter muscle function is trained and measured using validated transperineal ultrasound (TPUS) methods. Change in rhabdosphincter function following preoperative PFM training programs and the relationship between the functionality of the rhabdosphincter and MUL has not been reported.
Methods: Twenty patients referred to a men&[prime]s health clinic for preoperative work-up prior to RP were prospectively recruited. Men who had previously undergone a prostate MRI examination received instruction about pelvic floor functional anatomy using anatomical drawings and models and via verbal instruction. Activation and training of the rhabdosphincter was undertaken using TPUS visual biofeedback. Patients were prescribed an individualised patient-centred PFM training program that focussed on rhabdosphincter activation at rest and during functional activities. TPUS assessment of rhabdosphincter function was completed prior to and at the completion of the preoperative PFM training program. Validated displacement measurements of the motion of the midurethra during voluntary PFM contractions was used as the landmark for rhabdosphincter function. MUL measurements were undertaken in the sagittal plane. Linear regression was used to determine the relationship between rhabdosphincter displacement and MUL. A paired t-test was used for analysis of the change in displacement
Results: The twenty patients were on average 66 (SD=7, range 54-77)yrs with mean MUL 14.8mm (SD=4.5, range 7.4-21.5mm). Rhabdosphincter displacement increased significantly following the PFM training program (2.6mm, 95%CI:2.0-3.1mm, P < 0.001). There was a significant positive relationship between MUL and rhabdosphincter displacement prior to and following the PFM training program (P < 0.001). For every additional 1mm of MUL, rhabdosphincter displacement increased by 0.4mm prior to and 0.5mm following the PFM training respectively.
Conclusions: A preoperative PFM training program induces changes in the voluntary activation of the rhabdosphincter. Rhabdosphincter activation during voluntary PFM contractions is also associated with preoperative MUL. The changes in rhabdosphincter function provide novel insights into our understanding of the male continence mechanism and may explain why preoperative pelvic floor muscle training improves continence recovery following RP.