Pelvic floor structural alterations in primiparas with stress urinary incontinence after vaginal delivery:A MRI study

ZHAO Yujiao; GAO Guangfeng; CUI Can; GUO Limei; HUANG Lixiang; ZHANG Jing; SHEN Wen

doi:10.19300/j.2018.L5057

Abstract：Objective To investigate the changes of the pelvic floor structure in primiparas suffering from stress uri-nary incontinence after vaginal delivery. Methods Forty-four primiparas under postpartum review at obstetrics department were prospectively collected in this study during March 2015-April 2016 in our hospital. Ninteen primiparas suffering from stress urinary incontinence (SUI) after vaginal delivery were selected as SUI group, 25 normal primiparas after vaginal deliv-ery were selected as Non-SUI control group, and 17 nulliparous women were selected as the normal control (NC) group. All the subjects underwent static and dynamic MRI. Two radiologists evaluated and measured the parameters of pelvic floor structures, during rest and strain state, including levator ani hiatus area (LHA), H line, M line, the distance from neck of bladder to PCL (B-PCL), the distance from cervix to PCL (U-PCL), retro vesicourethral angle (RVA), anterior angle of urethra (AUA), lev-ator ani plate angle (LPA), urethral height (D), the distance from bladder neck to the midline of the long axis of pubis (S) and if there was bladder funnel. The measurements consistency between the two observers were calculated by intra-class correla-tion coefficient (ICC), one-way ANOVA was used to compare the difference of all the measurements among three groups and post-hoc Scheffe test was used in the paired comparisons. Besides, the different proportion of bladder funnel in the three groups were compared by chi-square test. Results In the strain state, the measurements including LHA, H line, M line, RVA, AUA in the SUI group were significant larger than that in the Non-SUI and NC groups (all P<0.05), and LPA in the SUI group was also larger than that in the NC group (P<0.05). Meanwhile, the B-PCL, U-PCL, D, and S in the SUI group were significant smaller than that in the Non-SUI and NC groups (all P<0.05). There were no significant difference in all the measurements between the Non-SUI and NC groups (all P>0.05). In the rest state, the measurements of LHA, RVA in the SUI group were larger, and the B-PCL, D were smaller than that in the NC group (all P<0.05). The proportion of bladder funnel in three group were 78.95％ (SUI group) , 4％ (Non-SUI group), 0％ (NC group), respectively, which showed significant differ ence (χ2=39.72, P<0.001). Conclusion Pelvic floor structures change significantly in the primipara suffering from SUI after vaginal delivery, implying some degree of levator ani muscle dysfunction, urethral activity increasing, internal urethral orifice with a poor closed integrity, urethral sphincter disability and a series of pathological state. MRI can be used to evaluate the degree and range of lesions comprehensively, and observe recovery or progress of pelvic floor structure after delivery dynamically.