The association between pelvic floor muscle function (PFM) and pelvic girdle pain (PGP)---A matched case control 3D ultrasound study. Britt Stuge*, Kaja Sætre, Ingeborg Hoff Brækken Manual Therapy 17 (2012)

Ann Dunbar PT,DPT,MS WCS

September 5, 2012

Primary Aim: To investigate the difference in voluntary pelvic floor muscle function in women with and without clinically diagnosed PGP.

Subjects:  49 consecutive women who were at least 6 months postpartum and were patients of physical therapists (diagnosis criteria listed in article) in Oslo, Norway, matched with 49 controls for age, number of vaginal deliveries and age of her children.

Study Design: 0ne-to-one matched case-controlled study

Methods:

Procedures

• Completed a questionnaire of sociodemographic data, gynecological health status, and functional status (see pg 151 for instruments used)
• PFM function assessed by visual observation and vaginal palpation with subject in supine.
• Vaginal manometry with middle of balloon placed 3.5 cm internal from vaginal introitus
• Vaginal 3D ultrasound with probe on perineum in sagittal plane as per recommendations of Dietz (2004)

--Participants performed 3 PFM contractions in supine and each recorded

 --In 18 participants this was repeated immediately for test-restest analysis

Outcome measures

Ultrasound measures:

Definitions: levator hiatus area, pubovisceral muscle length given in study

• Axial plane analyses: measurements of the levator hiatus area, pubovisceral muscle length, anterior-posterior and transverse distance of the levator hiatus and levator urethral gap. Captured 3x. One trial contracton out of 3 producing the greatest narrowing of the levator hiatus A-P distance was used for further analyses.
• Sagittal plane analyses: measurements of the height and displacement of bladder, rectum, levator plate. Based on reliable and valid methods used, more than 50% of symphysis had to be visible to used for analysis (Majida et al, 2008; Braekken et al, 2009).

Manometry:

• PFM strength calculated as mean of 3 maximal voluntary contractions utilizing manometry with simultaneous observation with inward movement of catheter and perineum during PFM contraction (Bo et al, 1990a, 1990b). Vaginal resting pressure was also calculated.
• PFM endurance defined as sustained maximal contractions with area under curve for 1^st 10 seconds utilized for further analyses.

Statistics:

Frequencies used for categorical data. Means with standard deviation used for continuous data. Student t-test used for normally distributed continuous variables and Mann-Whitney U test for non-normally distributed continuous variables to analyze differences between cases and controls. Pearson Chi-Square used for categorical data.  Odds ratios adjusted for BMI and years of education.  All analysis adjusted for age and parity. Test-retest intra-tester reliability analyzed using ICC with 95% CI (see pg 152 for classification). Power calculation: assumed 25% less constriction of hiatal area to be clinically important. Power calculation done to determine number of subjects needed for each group.

Results

• 49 women matched according to age and parity; no significant differences in demographic variables between groups with age, parity, education level, episodes of UI, and POP.
• Women with postpartum PGP (PPGP) had significantly higher BMI and had more pain and disability than controls.
• No significant difference in voluntary PFM function based on manometry but women with PGP had tendency toward higher vaginal resting pressure.
• Women with PPGP had smallest levator hiatus at rest and at maximal pfm contraction.
• Women with BMI > 25 kg/m² had OR of more than 3 for having PPGP.
• Women with PPGP had tendency to have higher vaginal resting pressure

Discussion

The findings of this study demonstrate no difference in PFM strength, endurance, and in ‘lifting’ ability between subjects and controls. Compared with matched controls, the levator hiatus together with BMI are significantly associated with PPGP. Results show that women with PPGP had a significantly smaller levator hiatus and a tendency toward a higher vaginal resting pressure. The authors suggest these findings might indicate increased activity of the PFM.  Results also suggest tendencies for low position of the bladder, greater reduction in muscle length during contraction and presence of pelvic organ prolapse in women with PGP.

Strengths: 

• Measurements of lift and squeeze of PFM contraction were previously shown to be reliable.
• PFMs are not flat so 3D ultrasound imaging provides better evaluation of muscle morphology.
• Ultrasonographer was trained and highly skilled.
• Subjects were women with clinically verified PPGP according to recommended criteria.
• Subjects were closely matched with controls regarding parity and age.

Weaknesses:

• Small sample size, weight and height of subjects no measured clinically

Clinical Implications:

1)  How do the findings from this study shape your thinking about interventions you would provide for a pt with PGP?

2) In your opinion, what do these findings suggest about deep stabilizing muscle motor control?

3)  The authors suggest that we can’t assume that prescribing PFM strengthening exercises will be appropriate for pts with PGP. How would you evaluate for this to discern the most appropriate exercise prescription for a patient with PGP?

4)  Research suggests a relationship between PGP and  parity related factors (Bjelland et al 2010). How do these findings influence your evaluation and treatment?

Background Information:

European guidelines for the diagnosis and treatment of pelvic girdle pain.

(Vleeming et al; 2008. Europ Spine J 17(6):794-819).

Pelvic girdle pain:

¡  Arises in relation to pregnancy, trauma, arthritis, and osteoarthritis

¡  Experienced between posterior iliac crest and gluteal folds; may radiate into posterior thigh

¡  Pain may occur in conjunction w/ or separately in symphysis