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Saturday, May 9, 2015

Pattern of Activation of Pelvic Floor Muscles in Men Differs With Verbal Instructions. Stafford R, et al. Neurourol Urodyn. 2015 March 1. Doi: 10.1002/nau.22745.

Michelle Spicka, DPT
May 6th, 2015
Pelvic Physical Therapy Distance Journal Club
Description: Pelvic floor muscle exercises have been found to help with post-prostatectomy urinary incontinence in men but there is a lack of consistency of the instructions used to teach men to activate the pelvic floor muscles.  Because the efficacy of a pelvic floor muscle exercise program for treatment of incontinence after prostatectomy is likely to depend on if and how the muscles of urinary continence are activated, optimal methods to achieve activation have received limited attention.
The aim of this study is to investigate the effect of instruction on activation of pelvic floor muscles in men as quantified by transperineal ultrasound imaging and to validate these measures with invasive EMG recordings.

Methods: Fifteen men aged 28-44 with no history of urological or neurological disease were included.  No participant had undergone previous training for the pelvic floor muscles.
Participants sat upright on a plinth with knees extended.  Three repetitions of voluntary pelvic floor contractions were performed with guidance of specific verbal instructions.  Contractions were sustained for 3 seconds and separated by 10 seconds rest. 
Four instructions were tested (and performed in random order, separated by 2 minutes rest):
1.       Tighten around the anus (predicted to target the anal sphincter)

2.       Elevate the bladder (predicted to target pubrorectalis)

3.       Shorten the penis (predicted to target striated urethral sphincter)

4.       Stop the flow of urine (predicated to target striated urethral sphincter and puborectalis)

Results: Displacement at the mid-urethra differed between instructions. 

1)      Peak mid-urethral displacement was greater during “shorten the penis” than “elevate the bladder” and “tighten the anus” but not “stop the flow of urine”

2)      Instruction had no differential effect on displacements at ventral urethral-vesical junction.

3)      The instruction that achieved maximum displacement of puborectalis for individual participants was distributed between “elevate the bladder”, “shorten the penis” and “stop the flow of urine”.

4)      Most participants achieved maximum displacement of ano-rectal junction with “tighten around the anus” and “stop the flow of urine”. 

5)      The greatest movement at the bulb of penis was most commonly observed for “tighten around the anus”.

6)      Instruction to “elevate the bladder” induced the greatest increase in abdominal EMG and intra-abdominal pressure.
Discussion:

1)      Verbal instructions used to encourage voluntary contraction of different pelvic floor muscles influences the pattern of urethral movement observed with ultrasound.

2)      Optimized activation of the striated urethral sphincter with limited increase in intra-abdominal pressure is best achieved with “shorten the penis” or “stop the flow of urine”. 

3)      “Tighten around the anus” targets activation of the anal sphincter muscle, although there is co-concomitant activation of the muscles that can affect the urethra but the activation of those muscles was less than for other instructions.

4)      The instruction that emphasized “elevation” caused a counter-productive increase in abdominal muscle activity and IAP that was greater than the other instructions.

5)      The relationship between movement on ultrasound and EMG provides evidence for the validity of interpretation of activity of specific pelvic floor muscles from motion of pelvic landmarks which supports the potential clinical use of US.

6)      The optimal instructions to activate pelvic floor muscles are likely those that induce the greatest amplitude of pelvic floor muscle shortening with minimal increase in abdominal muscle activity and IAP but one instruction does not achieve the same pattern of activation for all men.

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