DOES HYSTERECTOMY ALTER PELVIC FLOOR MUSCLE FUNCTION?
T. CAMANONG, N. SUBRAMANIAM, T. FRIEDMAN, H. DIETZ;
Sydney Med. Sch. Nepean, Sydney, Australia.
Introduction: Hysterectomy is a routinely performed gynaecological procedure to address common benign and malignant conditions of the reproductive tract in women. It has been suggested that denervation during hysterectomy may have a detrimental effects on pelvic floor muscle (PFM) function .
Objective: We aimed to investigate the effect of hysterectomy by any route on PFM function, both clinically and sonographically. The null hypothesis was: prior hysterectomy is not associated with reduced PFM function.
Methods: This was a retrospective study of 1,191 women who attended a tertiary urogynaecological unit between 5/2013 to 3/2016. They were assessed using a standardized clinical interview, clinical examination using the POP-Q, Modified Oxford Scale (MOS), and 4D translabial ultrasound (TLUS). A history of hysterectomy, route and indication were recorded. Patients who had had a hysterectomy for prolapse were excluded from the analysis. MOS was rated as the mean of left and right levator strength, graded on a scale from 0 to 5. Sonographic measures of PFM function were obtained at a later date using proprietary software, blinded against all other data . We measured reduction in anteroposterior hiatal diameter and bladder neck elevation by comparing measurements taken at rest and during maximum PFMC (Figure 1). Associations between PFM function and hysterectomy were quantified using T-Test and ANOVA. A P<0.05 was considered statistically significant.
Figure 1. Assessment of pelvic floor muscle function by 4D translabial ultrasound. A and C are obtained at rest, while B and D are obtained on maximal pelvic floor muscle contraction. A and B shows bladder neck displacement. C and D shows hiatal anteroposterior diameter reduction.
Results: A total of 1,191 women were seen during the study period. 133 women were excluded due to missing US volumes in 46, poor image quality in 2, vaginal hysterectomy for prolapse in 80 and missing indication in 5, leaving 1058 for analysis. Mean age was 55 (SD 13.5, range 16-89) years with an average BMI of 29 (SD 6.6, 16-64) kg/m2. The median parity was 2 (IQR 2-3, 0-9) and 88.9% (n=940) were vaginally parous. The mean age at first vaginal delivery was 24 (SD 5.0, range 14-42) years. 29.8% (n=315) had a history of instrumental delivery.
73.7% (n=780) of women reported stress incontinence, while urge incontinence was reported by 72.8% (n=770). 28.2% (n=298), 40.1% (n=424), and 34.0% (n=360) had urinary frequency, nocturia and voiding difficulty respectively. 541 (51.1%) women reported prolapse symptoms. 48.2% (n=510) had symptoms of obstructive defecation, while 13.7% (n=145) reported anal incontinence. Among these women, 26.2% (n=277) had had a hysterectomy, of which 70.4% (n=195) were via the abdominal and 29.6% (n=82) via the vaginal route.
Mean contractility of the PFM on palpation, measured by MOS, was 2 (SD 1.1, range 0-5). Mean bladder neck displacement was 5.8 (SD 3.7, range 0.1-29.1) mm and the mean reduction in AP hiatal diameter was 8.3 (SD 5.0, range 0.1-30.6) mm. On univariate analysis using T-Test, there was no statistically significant difference in PFM function between women with and without hysterectomy (see Table). Results remained virtually unchanged when comparing pelvic floor muscle function for different routes of hysterectomy on ANOVA.
Pelvic floor muscle function and hysterectomy
Pelvic floor muscle function
No hystsrectomy (n= 781)
Mean Oxford Grading
Bladder neck elevation (mm)
Reduction of hiatal diameter
TABLE 1. Univariate analysis (T-test) of the association between clinical and sonographic measures of PFM function and hysterectomy.
Conclusions: Hysterectomy is unlikely to impact on PFM contractile function assessed clinically or sonographically.
References: 1. Facts Views Vis Obgyn (2009) 1(3): 194-207.
2. Int Urogynecol J (2011) 22(9): 1085-97.