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Hodges P1, Stafford R1, Coughlin G1
1The University of Queensland, Brisbane, Australia
Background: Recent research has highlighted the importance of the complex interaction of striated muscles of the pelvic floor for control of continence in men. There is preliminary evidence that function of this system may be a determinant of recovery of continence after prostatectomy.
Purpose: To compare anatomical and dynamic features of contraction of pelvic floor muscles that contribute to urinary continence between men with and without incontinence after prostatectomy, and men with no prostate cancer or incontinence to better understand why some men recover continence and others do not.
Methods: Sixty-three men were grouped according continence status and prostate cancer history; men with incontinence after prostatectomy (PPI; n=20), men who were continent after prostatectomy (PPC; n=23), and a control group without incontinence or prostate cancer (CC; n=20). Transperineal ultrasound imaging was used to record position and motion of pelvic structures associated with contraction of the striated urethral sphincter (SUS), puborectalis (PR) and bulbocavernosus (BC) muscles during; (i) sustained MVC, (ii) sub-maximal voluntary contraction, and (iii) evoked cough. Image frames were exported from the recorded video data and used to calculate the displacements of the pelvic structures in addition along with anatomical features of the urethra and ano-rectal junction. One-way ANOVAs were used to compare each of the variables between groups.
Results: Greater displacement associated with SUS, PR and BC muscle shortening was observed for the PPC than PPI group during MVC (All: P 0.01). There were no differences between PPC and CC groups. When displacements related to SUS and PR contraction were considered together, the greatest separation between groups was achieved using thresholds of >4.1mm SUS displacement and >1.9mm PR displacement during MVC. This was achieved by 18/23 (78%) of the PCC group, but only 6/20 (30%) of the PPI group. During sustained holding, the PPC group demonstrated a greater mean SUS displacement (sustained over 5 s) (than both PPI (P=0.033) and CC (P=0.047) groups. During cough, the PPC group achieved greater SUS (P=0.025) and BC (P=0.003) displacement than PPI group, with less PR lengthening (i.e. bladder neck descent; P=0.005). Urethral length was not different between PPC and PPI groups, but the position of the ano-rectal junction was lower in the PPC than PPI and CC groups.
Conclusion(s): This study shows that men who are continent after prostatectomy can be discriminated from those who are incontinent can be discriminated on the basis of capacity to activate pelvic floor muscles. In general, men who were continent achieved greater shortening of the SUS, PR and BC muscles than those who are incontinent. An additional observation was that for sustained contraction, men who have regained continence after prostatectomy had achieved greater performance than controls. This suggests that activation in excess of that typically required may be necessary to maintain continence.
Implications: These data support the notion that pelvic floor muscle activation is a key determinant of continence recovery after prostatectomy and suggest that the capacity to shorten the SUS >4.1mm and the PR >1.9mm best distinguished between groups and might be a useful clinical target for conservative treatment programs.
Keywords: Prostatectomy, Incontinence, Pelvic floor muscles
Funding acknowledgements: National Health and Medical Research Council of Australia
Purpose: To compare anatomical and dynamic features of contraction of pelvic floor muscles that contribute to urinary continence between men with and without incontinence after prostatectomy, and men with no prostate cancer or incontinence to better understand why some men recover continence and others do not.
Methods: Sixty-three men were grouped according continence status and prostate cancer history; men with incontinence after prostatectomy (PPI; n=20), men who were continent after prostatectomy (PPC; n=23), and a control group without incontinence or prostate cancer (CC; n=20). Transperineal ultrasound imaging was used to record position and motion of pelvic structures associated with contraction of the striated urethral sphincter (SUS), puborectalis (PR) and bulbocavernosus (BC) muscles during; (i) sustained MVC, (ii) sub-maximal voluntary contraction, and (iii) evoked cough. Image frames were exported from the recorded video data and used to calculate the displacements of the pelvic structures in addition along with anatomical features of the urethra and ano-rectal junction. One-way ANOVAs were used to compare each of the variables between groups.
Results: Greater displacement associated with SUS, PR and BC muscle shortening was observed for the PPC than PPI group during MVC (All: P 0.01). There were no differences between PPC and CC groups. When displacements related to SUS and PR contraction were considered together, the greatest separation between groups was achieved using thresholds of >4.1mm SUS displacement and >1.9mm PR displacement during MVC. This was achieved by 18/23 (78%) of the PCC group, but only 6/20 (30%) of the PPI group. During sustained holding, the PPC group demonstrated a greater mean SUS displacement (sustained over 5 s) (than both PPI (P=0.033) and CC (P=0.047) groups. During cough, the PPC group achieved greater SUS (P=0.025) and BC (P=0.003) displacement than PPI group, with less PR lengthening (i.e. bladder neck descent; P=0.005). Urethral length was not different between PPC and PPI groups, but the position of the ano-rectal junction was lower in the PPC than PPI and CC groups.
Conclusion(s): This study shows that men who are continent after prostatectomy can be discriminated from those who are incontinent can be discriminated on the basis of capacity to activate pelvic floor muscles. In general, men who were continent achieved greater shortening of the SUS, PR and BC muscles than those who are incontinent. An additional observation was that for sustained contraction, men who have regained continence after prostatectomy had achieved greater performance than controls. This suggests that activation in excess of that typically required may be necessary to maintain continence.
Implications: These data support the notion that pelvic floor muscle activation is a key determinant of continence recovery after prostatectomy and suggest that the capacity to shorten the SUS >4.1mm and the PR >1.9mm best distinguished between groups and might be a useful clinical target for conservative treatment programs.
Keywords: Prostatectomy, Incontinence, Pelvic floor muscles
Funding acknowledgements: National Health and Medical Research Council of Australia
Topic: Women's & men's pelvic health
Ethics approval required: Yes
Institution: The University of Queensland
Ethics committee: Medical Research Ethics Committee
Ethics number: 2017001736/HREC/1739
All authors, affiliations and abstracts have been published as submitted.
