The Effect Of Injuries Of The Levator Ani Muscle On Pelvic Floor Function In The Early Postpartum Period

Objective The aim of this study was to explore the effect of injuries of the levator ani muscle on pelvic floor function in the early period after vaginal delivery and to evaluate the changes of pelvic floor function of the women with levator ani muscle defect in 3 months and 6 months after childbirth.Materials and methods Part ?:The vaginal delivery primiparas were collected during 2015.10~2018.01 from Tianjin First Center Hospital,and all the subjects underwent an MRI examination of the pelvic floor 6 weeks after delivery by using static and dynamic scan.Static scan includes axial and sagittal T2 WI FSE technique;dynamic scan sequences include midsagittal Balanced TFE and axial and sagittal Single-shot TSE at Valsalva maneuver.From the axial T2 WI images,2 senior radiologists evaluate the continuity of muscle fiber of the levator ani muscle,and the subjects were divided into 2 groups: normal group with continuous and intact muscle fiber and avulsion group with discontinuous fiber.Agreement in the diagnosis had to be unanimous according to all 2 assessors.Pelvic floor dimensions at rest and Valsalva maneuver were measured,including levator hiatus area(LHA),anteroposterior diameter(LHL),width(LHW),the distance from bladder bottom and cervix to PCL line,H line drawn from the inferior border of the symphysis pubis to the posterior border of the anorectal junction(ARJ),Line M traced between the ARJ and the PCL,and whether bladder funnel is present.Independent sample t test was used to analyze the difference of the dimensions between the normal group of the levator ani muscle and the avulsion group at rest and Valsalva maneuver,and the ratio of bladder funnel between the two groups was compared by chi square test.Part ?:The women with tearing of the levator anal muscle were followed up at 3 months and 6 months postpartum,and the pelvic floor MR was reviewed.The methods of the scan and statistical analysis are the same as those of the part ?.The pertinent dimensions of the pelvic floor were measured.One-way repeated measures ANOVA was used to analyze the changes among 6 weeks,3 months and 6 months postpartum.Results Part ?: In all,75 primiparous women were diagnosed nomal(n=37)and with(n=38)levator ani muscle avulsion injury.At rest,women with avulsion presented enlarged hiatus and longer M line and larger ARA in comparison to women without avulsion,P<0.05.At Valsalva maneuver,women with avulsion presented enlarged hiatus,longer H,M line,and lower position of the bladder and uterus than those of women without avulsion,P<0.05,whereas ARA and the ratio of bladder funnel was found to be similar in the 2 groups(P>0.05).Part ?:20 primiparas were followed up,and there was no difference about the dimensions(P>0.05).Conclusions At 6 weeks after vaginal delivery,the pelvic floor function reduces in women with avulsion of the levator ani muscle.The decrease of pelvic floor function in participants with avulsion of levator ani muscle was not changed within 6 months postpartum.