McLean et al. Pelvic Floor Muscle Training in Women with Stress Urinary Incontinence Causes Hypertrophy of the Urethral Sphincters and Reduces Bladder Neck Mobility During Coughing. Neurourology and Urodynamics 32:1096-1102(2013).

Pelvic Physiotherapy Think Tank
December 4, 2013
Michelle Spicka, DPT

Objective:  To determine the effect of a 12 week pelvic floor muscle training program on urethral morphology and mobility in women with stress urinary incontinence (SUI).

Study Design/Method: 

1.       To date, there has not been investigation of the impact of pelvic floor muscle (PFM) training on urethral structure, support or mobility.

a.       Measurements of urethral trajectory and acceleration during functional tasks such as coughing have shown that women with SUI demonstrate a larger excursion of the urethra during coughing maneuvers than their continent counterparts.

b.      These results suggest that the urethra is not effectively held in place behind the pubic symphysis to ensure that it is compressed against the pelvic floor when there is an increase in intra-abdominal pressure, which in turn suggests that women with SUI have ineffective endopelvic fascia and/or PFMs that are slow or ineffective in offering support to the urethra

2.       Women included in the study were over 18, had symptoms of SUI with or without urge incontinence, noturia or anterior compartment prolapsed, but not if they had fecal incontinence. 

a.       Volunteers who met the screening criteria underwent urodynamics and those with detrusor instability were excluded

b.      Women found to have neurologic defects, pelvic mass or prolapsed greater than stage 2 were also excluded

3.       40 women were ultimately chosen with 20 randomly placed in the intervention group and 20 in the control group

a.       Data collection included a 3-day bladder diary, bladder volume assessment via trans-abdominal ultrasound, pad test and completion of the Urogenital Distress Inventory and Incontinence Impact Questionnaire.  Ultrasound imaging of the pelvic structures also was performed during coughing and Valsalva in the lithotomy position and in standing.

4.       Intervention             

a.       Women assigned to the PFM strength training group attended weekly private PT sessions

                                                                           i.      3 sets of 12 PFM contractions daily

                                                                         ii.      Reassessment after 12 weeks

 Outcome/Results:  

1.       There was no difference in the bladder diary, pad test or questionnaire scores between the groups at the start of the study.  Post treatment, significant differences were found for the bladder diary and the Incontinence Impact Questionnaire in the treatment group only.

2.       No change in the vertical position of the bladder neck relative to the levator plate at rest was noted in both groups following the study period.

3.       In both groups and positions (supine and standing), there was more bladder neck displacement during the Valsalva noted at post-treatment vs pre-treatment.

4.       In the treatment group, in both supine and standing, there was a significant reduction in bladder neck displacement during coughing after the study period compared to before the study period.  The control group did not demonstrate the same effect.

Conclusion:

1.       This study demonstrates that supervised PFM training reduces urethral mobility during coughing and increases the cross-sectional area of the urethra but does not reduce the extent of bladder neck excursion seen during maximal effort Valsalva maneuvers.

a.       The action of the PFM has been shown to hold the urethra in place such that it can be compressed between the anterior vaginal wall and the pubic symphysis during tasks that increase intra-abdominal pressure.

2.       Strengthening of the PFMs was not expected to appreciably improve the integrity of the surrounding connective tissues so therefore it was not expected that the training program would reduce bladder neck excursion during maximal effort Valsalva maneuver (which challenges the endopelvic fascia.

3.       Participants in both groups demonstrated more bladder neck descent after the 12 week period

a.       Maybe due to learning how to perform a true maximal Valsalva  or being more comfortable with testing.

4.       PFM contraction strength on maximal voluntary contraction was positively associated with urethral sphincter length, cross-sectional area and a surrogate measure for volume.

a.       Suggests that training the PFMs may cause improvements in striated urethral sphincter volume and function.                     

                                                                           i.      Miller et al (Obstet Gynecol 2007) showed that women without a visible puboccygeus muscle on MRI could still increase their urethral  closure pressures when performing a PFM contraction.

b.      The researchers of this study postulate that PFM exercises performed by the treatment group in this study resulted in hypertrophy of the urethral sphincter.

5.       Also noted was that the 3-day bladder diary appeared more sensitive to change induced by PFM training than a standardized pad test

a.       Multiple reasonings for that conclusion including urge incontinence vs SUI

6.       The Incontinence Impact Questionnaire showed significant improvements but the Urogenital Distress Inventory did not show any significant difference in either group.

a.       Choice of questionnaire

Thought Questions:

1.       How does this study affect patient education and physician education…physical therapy can help with urethral hypermobility!