孕晚期女性肛提肌及邻近结构磁共振三维结构变化研究

目的探讨妊娠晚期正常妇女肛提肌三维模型特点。方法选取2013年11月至2015年3月就诊于南方医科大学南方医院行常规产检的孕晚期初孕妇27例,均为单胎、头位,孕30~40周,宫高、腹围检查均在正常范围,孕前及孕期均无盆腔器官脱垂(POP)及压力性尿失禁(SUI)症状。对照组为无SUI、POP临床症状的未育健康青年妇女志愿者25例。运用磁共振(MRI)三维重建技术构建妊娠晚期及正常妇女肛提肌三维模型,对比两组阴道形态、肛提肌裂孔形态变化,肛提肌参数以及膀胱颈、宫颈和肛直肠连接处到耻尾线(PCL)的距离。结果对照组中肛提肌裂孔均为"V"形,孕妇组肛提肌裂孔22例"V"形,5例"U"形,孕妇组肛提肌裂孔前后径较对照组增大[LH-L,(60.01±6.63)mm vs.(54.03±5.09)mm,P0.01],横径增大[LH-W,(36.61±3.58)mm vs.(32.58±4.09)mm,P0.01],耻骨直肠肌两侧距耻骨联合下缘距离增大[左侧LSG-L(23.19±3.42)mm vs.(18.79±2.52)mm,P0.01;右侧LSG-R(22.10±3.58)mm vs.(18.34±2.50)mm,P0.01],肛提肌板角度增大[LPA(49.93±4.38)°vs.(42.94±4.38)°,P0.01],肛提肌体积变小[LVOL(24.57±5.76)cm3vs.(33.91±6.28)cm3,P0.01];邻近结构阴道形态发生变化,对照组阴道形态均为"H"形,孕妇组21例"H"形,6例近"V"形,孕妇组器官到PCL的距离较对照组均变小(P0.05)。结论妊娠晚期妇女肛提肌结构发生重塑,趋向松弛改变,邻近阴道形态可发生变化,器官位置下移。     

女性慢性盆腔疼痛综合征患者盆底超声影像学改变特征的分析

目的探讨女性慢性盆腔疼痛综合征(chronic pelvic pain syndrome,CPPS)患者盆底超声影像学改变特征,为CPPS的诊治提供依据。方法选取2015年1月至2016年12月在大连市妇女儿童医疗中心就诊的66例CPPS患者和81例非CPPS健康人群,比较静态和Valsalva状态下膀胱颈与耻骨联合前下缘水平线之间的距离(BND)、膀胱底与耻骨联合前下缘水平线之间的距离(BSD)、尿道长度、生殖道裂孔前后径、肛直肠角度等参数的变化。比较两组在肛提肌裂孔前后径、横径及面积,阴道旁间隙面积,肛提肌面积,肛提肌厚度等参数的变化特征。结果研究组静息状态下生殖道裂孔前后径[(53.23±7.70)mm vs.(57.53±9.59)mm]小于对照组(P0.05),肛直肠角度[(115.69±13.28)°vs.(109.31±13.26)°]大于对照组(P0.05);Valsalva状态下BSD[(6.70±14.91)mm vs.(0.13±15.10)mm]大于对照组(P0.05)。研究组肛提肌裂孔前后径[(51.25±6.14)mm vs.(58.80±7.36)mm]、肛提肌裂孔横径[(39.44±6.07)mm vs.(47.92±8.18)mm]、肛提肌裂孔面积[(13.74±2.51)mm~2 vs.(18.31±3.47)mm~2 ]、阴道旁间隙左右侧面积[(2.07±0.71)mm~2 vs.(2.94±1.19)mm~2 ,(2.02±0.52)mm~2 vs.(2.87±0.87)mm~2 ]均明显小于对照组(P0.0001)。肛提肌中间厚度[(5.59±1.99)mm vs.(4.60±1.92)mm]大于对照组(P0.05)。结论女性CPPS盆底超声影像学显示为肛提肌痉挛性特征。     

不同膀胱容量会阴超声检查在压力性尿失禁诊断中的意义

目的探讨不同膀胱容量对女性压力性尿失禁(SUI)各项超声指标的影响以及超声在女性SUI诊断中的应用价值。方法对2005年6月至2007年3月南京军区福州总医院妇产科收治的42例SUI患者(SUI组),选择其中10例,禁水、禁食4h,逆行膀胱灌注(100、200、300、500mL);选择同期收住院的无SUI和(或)盆腔器官脱垂,因子宫良性肿瘤行子宫切除术的患者35例为对照组。分别在安静状态下和屏气用力动作时,采用经会阴超声检测患者膀胱颈的移动度(Mu)、膀胱颈至耻骨联合后缘中点的距离(Br、Bs),并将两种状态下的图像冻结并储存入计算机;运用计算机程序测量两种状态下的尿道膀胱后角(αr、αs)和膀胱颈的旋转角度(θ)。结果不同膀胱容量的各项超声指标检测结果类似(P>0.05)。SUI组与对照组安静及屏气用力状态时Mu、Br、Bs、αr、αs、θ、ΔB(Br与Bs的差值)值分别为(1.61±0.31)cm、(3.86±0.67)cm、(4.80±0.69)cm、(118.33±9.48)°、(134.93±14.67)°、(30.31±4.05)°、(0.91±0.14)cm与(0.91±0.17)cm、(2.64±0.37)cm、(2.92±0.42)cm、(93.66±6.52)°、(103.29±9.23)°、(15.83±2.58)°、(0.27±0.13)cm,两组各项指标比较差异均有统计学意义(P<0.01)。SUI组Mu、ΔB、θ与SUI的严重程度呈正相关(r分别=0.884,0.908,0.838,P<0.01)。结论(1)不同膀胱容量对女性SUI的各项超声指标无影响。(2)尿道高活动性是SUI的病因之一。(3)会阴超声在SUI的诊断中具有重要的应用价值。     

妊娠及分娩对盆底功能影响的探讨

目的:探讨妊娠晚期和产后早期女性盆底功能的变化情况.方法:随机抽取2007年7-10月在广州医学院第一附属医院门诊产前检查的晚期妊娠孕妇46例,分别在妊娠晚期及产后6～8周及产后12～14周对压力性尿失禁(SUI)发生率以及产后不同时期会阴B超检查膀胱颈移动度情况进行研究.结果:单纯国际尿失禁问卷和护垫实验联合国际尿失禁问卷两种方法评价SUI的发生率分别为:妊娠晚期组47.83%,39.13%;产后6～8周组21.74%,15.22%;产后12～14周组17.24%、13.79%.产后6～8周组SUI发生率均较妊娠晚期组降低,差异有统计学意义(P<0.05);产后12～14周组SUI发生率均较产后6～8周组降低,但差异无统计学意义(P>0.05).产后12～14周组膀胱角度、膀胱颈旋转角度较产后6-8周组明显减小[(88.11 ±13.36)°vs(82.17±10.28)°;(21.67±10.64)°vs(16.79 ±8.57)°],差异有统计学意义(P<0.05).结论:妊娠和分娩对盆底功能有一定的损伤,产后盆底功能有一定的康复趋势.     

盆底器官脱垂患者肛提肌的动态MRI研究

目的:探讨盆底器官脱垂(POP)患者肛提肌的动态MRI表现特征,建立基于MRI的盆底肌肉和韧带损伤的诊断技术。方法:POP组32例,对照组15例。分别比较两组肛提肌裂隙、髂尾肌厚度、耻骨直肠肌厚度、髂尾肌角度和肛提肌板角度的变化。结果:(1)POP组肛提肌裂隙面积较对照组明显增大(P=0.008);(2)POP组左右侧髂尾肌和右侧耻骨直肠肌厚度在静息位和最大腹压时均较对照组薄,差异有统计学意义(P均<0.05);对比腹压作用前后肛提肌厚度的变化,两组差异均无显著性(P均>0.05);(3)最大腹压时,POP组髂尾肌角度和肛提肌板角度较对照组明显增大(P=0.001和0.007);比较腹压作用前后的角度变化,POP组有显著差异(P=0.003和0.044)。结论:MRI检查可以很好地观察肛提肌的形态,动态检查还可以评价肛提肌的功能状态。     

绝经后压力性尿失禁患者盆底肌电图特征研究

目的:采集描述绝经后压力性尿失禁(SUI)患者的盆底肌电图,探讨SUI盆底肌电图的变化特征。方法:选择30例绝经后SUI患者为研究组,另招募30例绝经后健康妇女为对照组。比较两组的一般情况,应用Keypoint肌电图分别采集研究组和对照组的盆底肛门括约肌、耻骨直肠肌肌电图,并比较两组运动单位电位(MUP)的时限、波幅、多相波百分率及募集电位的平均波幅。结果:两组肛门括约肌肌电图比较:轻度收缩相时研究组患者MUP时限、波幅、多相波百分率分别为8.31±0.80 ms、514.79±29.05μV、16.90±2.64%,均明显大于对照组;重度收缩相时研究组募集电位平均波幅661.56±34.02μV,明显小于对照组,差异均有统计学意义(P0.01)。两组耻骨直肠肌肌电图比较:轻度收缩相时研究组患者MUP时限、波幅、多相波百分率分别为8.47±0.97 ms、498.39±29.98μV、17.38±3.14%,均明显大于对照组;重度收缩相时研究组募集电位平均波幅600.49±36.12μV,明显小于对照组,差异均有统计学意义(P0.01)。结论:绝经后SUI患者盆底肌电图较正常绝经后妇女有明显的改变。     

盆底功能障碍性疾病盆底解剖学静动态磁共振成像研究

目的:通过静动态磁共振成像(MRI)检查,比较女性盆底功能障碍性疾病(PFD)患者及正常女性盆底解剖结构改变,探讨盆底特定解剖学异常是否与PFD有关,为盆底重建手术提供客观依据。方法:选择2008年1月至2009年3月确诊为PFD患者46例为研究对象(PFD组),其中盆腔器官脱垂(POP)24例,压力性尿失禁(SUI)10例,POP合并SUI12例;同期选取正常女性14例为对照组。采用静动态MRI进行盆底扫描。比较两组髂尾肌、耻尾肌及耻直肌静动态面积、肛提肌裂孔静动态宽度、膀胱尿道后角、LH线及M线长度、肛提肌角等参数值的变化。结果:PFD组患者静态髂尾肌、耻尾肌、耻直肌的面积大于动态,肛提肌裂孔宽度在静态时小于动态(P<0.05)。而对照组以上参数值在静动态下无明显改变(P>0.05)。PFD组患者膀胱尿道后角、LH线、M线均大于对照组,肛提肌角小于对照组(P<0.05)。结论:MRI能清楚显示盆底解剖结构及功能,肛提肌的形态及功能异常与PFD有关。     

脐带间充质干细胞治疗产后盆底功能缺陷的初步临床研究

目的:探讨人脐带间充质干细胞(huCMSCs)复合富血小板血浆(PRP)盆底肌多点注射治疗产后盆底功能缺陷的疗效。方法:选择2017年10月至2018年10月在临沂市妇幼保健院已完成产后盆底康复训练,但恢复效果不佳的二胎及以上经阴分娩高龄女性10例,行异体huCMSCs复合PRP盆底肌多点注射治疗。比较治疗前及治疗后1年其静息、缩肛、Valsava三种状态下盆隔裂孔面积、盆底Ⅰ类和Ⅱ类肌纤维的肌力分布及阴道收缩压变化,并进行问卷调查,了解满意度及整体印象改善度(PGI-I)评分。结果:盆隔裂孔面积治疗后静息状态较治疗前显著变小(P0.05),治疗前后盆底Ⅰ类、Ⅱ类肌纤维肌力分布差异有统计学意义(P0.01),肌力明显增加;治疗后阴道收缩压力除1例外均有不同程度增加,整体呈现上升趋势,治疗前后阴道收缩压明显升高,差异有统计学意义(P0.05);治疗后CD3、CD4、CD4/8、B细胞、NK细胞等淋巴细胞亚群无明显变化(P0.05);治疗后满意度评分较治疗前明显改善(4.61±0.42 vs 2.13±0.45,P0.05),PGI-I评分为6.47±0.25。结论:huCMSCs复合PRP盆底肌多点注射治疗对产后盆底功能缺陷具有治疗作用,且无免疫原性,是治疗产后盆底功能缺陷安全、微创、有效的治疗办法。     

应用盆底超声检查探讨肛提肌损伤与盆腔器官脱垂顶端支持结构的相关性

目的应用盆底超声检查探讨盆腔器官脱垂(pelvic organ prolapse, POP)患者肛提肌损伤与盆底顶端支持的相关性。方法回顾性纳入2014年5月至2018年12月于北京大学人民医院妇科术前通过POP定量分期系统(pelvic organ prolapse quantitation, POP-Q)Ⅲ～Ⅳ期的POP患者767例,所有患者均行盆底超声检查,评估肛提肌损伤情况及测量肛提肌裂孔面积。根据超声表现是否存在肛提肌损伤分为两组进行相关因素分析,并对肛提肌损伤组进行多因素分析。结果超声发现肛提肌损伤415例(54.1%),无损伤352例(45.9%)。损伤组D点位置均值(-1.11±2.94)cm,无损伤组均值(-1.85±2.48)cm,差异有统计学意义(P 0.05)。多因素回归分析显示,D点位置下移和裂孔面积增大是肛提肌损伤比例增加的独立危险因素,差异有统计学意义(P 0.05)。线性回归分析发现D点位置下移与肛提肌损伤比例增加存在高度正相关(R=0.856),拟合度较好(R~2=0.733)。结论肛提肌损伤与POP顶端支持有显著相关性。盆底超声能为临床提供可靠的评价POP的影像学辅助检查手段。     

盆腔器官脱垂盆腔器官及肛提肌动态三维模型构建方法研究

目的探讨利用动态磁共振成像(magnetic resonance imaging,MRI)原始数据集构建盆腔器官脱垂(pelvic organ prolapse,POP)盆腔器官及肛提肌动态三维模型的方法及意义。方法选取1例于2014年10月在南方医科大学南方医院行盆腔动态MRI扫描的POP患者,利用计算机三维重建软件构建静息及最大脱垂状态骨盆、盆腔器官及肛提肌三维模型,并对其进行三维测量,包括:肛提肌板角度,肛提肌裂孔横径及前后径;膀胱颈、宫颈内口、肛管直肠连接处距耻尾线(pubococcygeal line,PCL)的投影距离。结果 (1)最大脱垂状态时膀胱失去正常形态,从阴道前壁向前下脱出;阴道前壁呈凹槽状,子宫从后下脱入阴道内;肛直肠向后下移位。(2)最大脱垂状态与静息状态相比,肛提肌板角度增大15.25°,肛提肌裂孔横径增大5.88 mm,肛提肌裂孔前后径增大16 mm。盆腔器官垂直方向下移:膀胱:43.46 mm,子宫:46.48 mm,直肠:18.91 mm。结论 POP盆腔器官及肛提肌动态三维模型可以再现POP患者达最大脱垂程度时盆腔结构的真实状态,是对静息盆腔器官及肛提肌数字化三维模型的重要补充,有望为盆底手术提供个体化的解剖学和功能学参考。     

Real-time in vivo assessment of levator ani muscle deformation in women

Objective

To study the deformation of the levator ani muscle in vivo with the use of real-time ultrasound imaging of the pelvic floor.

Study design

Thirty-two women with symptoms of pelvic floor dysfunction underwent real-time in vivo assessment of the strain of the pelvic floor during Valsalva effort. All participants underwent clinical examination, urodynamics and 3D/4D translabial ultrasound scan of the pelvic floor. The deformation curves of the levator ani muscle were plotted and the difference in compliance according to the grade of urogenital prolapse was measured. One-way ANOVA and Spearman's correlation were used to test for significance of the relationship between variables (significance level P < 0.05). Test–retest analysis of the ultrasound measurements of the levator hiatal dimensions was also conducted using intra-class correlation coefficient (ICC).

Results

The deformation curve of the levator hiatus showed a non-linear relationship with gradually increased Valsalva force, which was quite pronounced in the pubourethralis subdivision of the levator ani muscle complex. Women with significant pelvic organ prolapse demonstrated a less compliant levator ani muscle close to its origin from the pubic bone than women with non-significant prolapse (median maximum strain 26% vs 32%, respectively, P = 0.03).

Conclusions

Real-time in vivo assessment of levator ani muscle deformation in women is feasible and yields significant information.     

超声评价肛提肌及其裂孔在女性盆腔器官脱垂中的进展

肛提肌及其裂孔是女性盆腔器官支持结构的重要部分，对女性盆腔器官起支撑作用。女性盆腔器官脱垂（pelvic organ prolapse，POP）是一种临床常见的盆底功能障碍性疾病，严重影响女性的心理和生理健康。POP病因复杂，与肛提肌损伤及肛提肌裂孔面积增大密切相关。因超声具有价廉、可重复性高、无辐射、患者易接受等优点，所以目前在女性盆腔器官检查中，经会阴超声技术得到越来越广泛的应用，应用经会阴超声技术评价肛提肌及其裂孔等盆腔结构的水平也逐渐提高。现主要从肛提肌及其裂孔的解剖结构、与POP的关系及经会阴超声技术在女性肛提肌及其裂孔检查中的应用进展进行综述。     

Three-dimensional ultrasound imaging of the levator hiatus in late pregnancy and associations with delivery outcomes

OBJECTIVE: To determine the correlations between dimensions of the levator hiatus in late pregnant nulliparous women, mode of delivery and length of second stage. METHODS: This was a prospective observational pilot study of 61 nulliparous women seen and examined between 36 and 40 weeks of pregnancy. A translabial ultrasound examination was undertaken, and three-dimensional volumes comprising the levator hiatus were recorded at rest, during a pelvic floor muscle contraction and on Valsalva. The volumes were analysed in a blinded fashion using proprietary software to determine linear dimensions and hiatal area. Information regarding delivery outcomes and course of labour was obtained from the obstetric database. Statistical analysis was undertaken for correlations between hiatal dimensions and labour outcomes. RESULTS: No consistent correlations were found between levator dimensions and delivery mode. However, an inverse correlation was demonstrated between the area of the hiatus, particularly on pelvic floor contraction, and length of total second stage. CONCLUSIONS: Levator hiatal dimensions are associated with the length of the second stage of labour. Although the numbers were small, our findings suggest that the effect of pelvic floor structures on progress in labour is worth further study.     

压力性尿失禁及盆底组织膨出患者肛提肌肌纤维直径和分型的研究

目的　探讨压力性尿失禁 (stressurinaryincontinence ,SUI)患者肛提肌肌纤维直径和分型的变化及其与SUI和盆底组织膨出 (pelvicorganprolapse ,POP)发病的关系。 方法　选择 15例SUI患者 (SUI组 )、19例POP患者 (POP组 )及 3例无SUI和POP的直肠癌患者 (对照组 ) ,术中行肛提肌活组织检查 (活检 )。常规组织学染色 ,镜下观察、测量肛提肌肌纤维直径 ,并进行分型。结果　SUI组和POP组患者肛提肌肌纤维密度减小 ,被丰富的纤维结缔组织充填、取代。含肌纤维的 4例SUI患者肛提肌肌纤维直径为 (2 4± 9) μm ,3例POP患者肛提肌肌纤维直径为 (2 4± 5 ) μm ,对照组肛提肌肌纤维直径为 (5 4± 11) μm。SUI组和POP组肛提肌肌纤维直径比较 ,差异无显著性 (P >0 0 5 ) ,但均较对照组肛提肌肌纤维直径缩短 (P <0 0 5 )。SUI、POP、对照组肛提肌肌纤维中Ⅰ型纤维 (慢纤维 )分别占 79 6 %、97 2 %和 77 2 % ,SUI、POP组Ⅱ型纤维 (快纤维 )比例均降低。对照组肛提肌肌纤维直径与年龄、绝经时间呈显著的负相关 (P =0 0 0 0 )。结论　SUI和POP患者肌肉的明显纤维化、退行性改变 ,快纤维减少 ,不利于在腹压增高时产生有力收缩。     

Interaction among apical support, levator ani impairment, and anterior vaginal wall prolapse

OBJECTIVE: To use a biomechanical model to explore how impairment of the pubovisceral portion of the levator ani muscle, the apical vaginal suspension complex, or both might interact to affect anterior vaginal wall prolapse severity. METHODS: A biomechanical model of the anterior vaginal wall and its support system was developed and implemented. The anterior vaginal wall and its main muscular and connective tissue support elements, namely the levator plate, pubovisceral muscle, and cardinal and uterosacral ligaments were included, and their geometry was based on midsagittal plane magnetic resonance scans. Material properties were based on published data. The change in the sagittal profile of the anterior vaginal wall during a maximal Valsalva was then predicted for different combinations of pubovisceral muscle and connective tissue impairment. RESULTS: Under raised intra-abdominal pressure, the magnitude of anterior vaginal wall prolapse was shown to be a combined function of both pubovisceral muscle and uterosacral and cardinal ligament ("apical supports") impairment. Once a certain degree of pubovisceral impairment was reached, the genital hiatus opened and a prolapse developed. The larger the pubovisceral impairment, the larger the anterior wall prolapse became. A 90% impairment of apical support led to an increase in anterior wall prolapse from 0.3 cm to 1.9 cm (a 530% increase) at 60% pubovisceral muscle impairment, and from 0.7 cm to 2.4 cm (a 240% increase) at 80% pubovisceral muscle impairment. CONCLUSION: These results suggest that a prolapse can develop as a result of impairment of the muscular and apical supports of the anterior vaginal wall.     

压力性尿失禁及盆底组织膨出患者肛提肌形态学的观察

目的 探讨肛提肌组织形态学的变化及其与压力性尿失禁(stress urinary incontinence,SUI)和盆底组织膨出(pelvic organ prolapse,POP)发病的关系。方法 选择15例SUI患者(SUI组)、19例POP患者(POP组)及3例无SUI和POP的直肠癌患者(对照组),术中行肛提肌活检,冰冻切片常规行HE染色、改良Gomori染色及非特异性酯酶(non—specific esterase,NSE)、酸性磷酸酶(acidphosphrase,ACP)、三磷酸腺苷酶(ATPase)染色,镜下观察肛提肌形态学变化。结果 成功获取肛提肌肌肉组织与未取得肛提肌肌肉组织的SUI患者的年龄、产次、绝经时间、疾病严重程度、漏尿点压力等比较,差异均无显著性(P>0.05)。SUI组和POP组患者肛提肌组织形态学表现为肌纤维密度降低,排列紊乱,被大量的结缔组织填充、取代,肌纤维周围炎性细胞浸润;单个肌纤维细胞既有核中心移位、纤维劈裂、外周吞噬及空泡变性等肌源性改变,也有肌纤维萎缩、角形变、同型纤维聚集等神经源性改变。结论 SUI和POP患者的肛提肌同时存在神经源性和肌源性改变,提示持续的盆底肌去神经支配和继发的肌源性改变,可能是SUR及POP的发病原因之一。     

Three-dimensional magnetic resonance imaging assessment of levator ani morphologic features in different grades of prolapse

OBJECTIVE: The study was undertaken to identify the morphologic changes in the levator ani in different grades of prolapse by using reconstructed three-dimensional models of magnetic resonance images (MRI) and to subclassify prolapse into different categories on the basis of their levator ani morphologic characteristics. STUDY DESIGN: Sixty-one women were studied, 8 women in stage I, 15 women in stage II, 22 women in stage III, 7 women in stage IV prolapse, and 9 asymptomatic volunteers with stage 0 prolapse. Axial, sagittal, and coronal T2-weighted pelvic magnetic resonance scans were obtained with the patient in the supine position. The three-dimensional models were reconstructed from the source images by using manual segmentation and surface modeling. The morphologic characteristics of the puborectalis were assessed on these reconstructed models by measuring (1). the levator symphysis gap, (2). the width of the levator hiatus, and (3). the length of the levator hiatus. To assess the iliococcygeus, we measured (1). the maximum width of the iliococcygeus, (2). the direction of its fibers that was assessed by measuring the iliococcygeal angle, and (3) the levator plate angle. Nine nulliparous asymptomatic women were studied as controls. RESULTS: Alterations in levator ani morphologic features are not dependent on the grade of the prolapse, and not all women with pelvic floor prolapse have abnormal morphologic features. In healthy control subjects, the iliococcygeal width measured less than 40 mm and the iliococcygeal angle measured less than 20 degrees. On the basis of the MRI findings, four patterns of changes in the levator ani have been identified. Both the levator symphysis gap and the levator hiatus, which is dependent on the puborectalis function, widen with increasing grade of prolapse. CONCLUSION: It is possible to subclassify prolapse on the basis of morphologic changes in the levator ani by using MRI. This may be a very useful predictor as to which patients have recurrent prolapse develop after surgery.     

Appearance of the levator ani muscle subdivisions in magnetic resonance images

OBJECTIVE: Identify and describe the separate appearance of 5 levator ani muscle subdivisions seen in axial, coronal, and sagittal magnetic resonance imaging (MRI) scan planes. METHODS: Magnetic resonance scans of 80 nulliparous women with normal pelvic support were evaluated. Characteristic features of each Terminologia Anatomica-listed levator ani component were determined for each scan plane. Muscle component visibility was based on pre-established criteria in axial, coronal, and sagittal scan planes: 1) clear and consistently visible separation or 2) different origin or insertion. Visibility of each of the levator ani subdivisions in each scan plane was assessed in 25 nulliparous women. RESULTS: In the axial plane, the puborectal muscle can be seen lateral to the pubovisceral muscle and decussating dorsal to the rectum. The course of the puboperineal muscle near the perineal body is visualized in the axial plane. The coronal view is perpendicular to the fiber direction of the puborectal and pubovisceral muscles and shows them as "clusters" of muscle on either side of the vagina. The sagittal plane consistently demonstrates the puborectal muscle passing dorsal to the rectum to form a sling that can consistently be seen as a "bump." This plane is also parallel to the pubovisceral muscle fiber direction and shows the puboperineal muscle. CONCLUSION: The subdivisions of the levator ani muscle are visible in MRI scans, each with distinct morphology and characteristic features.     

Volume sonography of the pelvic floor in nulliparous women and after elective cesarean section.

OBJECTIVE: To describe the sonographic appearance of the pelvic floor which has not been stressed by forces of labor or vaginal delivery in pregnant women and after childbirth. SUBJECTS AND METHODS: In a prospective observational study 14 nulliparous women during first trimester pregnancy and 26 primiparous women after elective cesarean were examined within the first week postpartum. The integrity of the internal anal sphincter expressed as the ratio between the anterior and the posterior internal anal sphincter muscle thickness (a/p-ratio), asymmetry of the levator ani muscle and the paraurethral fixation of the lateral vaginal edges at the arcus tendineus were assessed using volume sonography. RESULTS: The a/p-ratio in nulliparous women was significantly higher (p<0.01) than after elective cesarean section. Asymmetry of the levator ani muscle did not differ between both groups but was more frequently in the nulliparous patients with an odds-ratio of 1.16 (CI 0.74-1.82). In both groups of women the paraurethral fixation of the lateral vaginal edges were above the suburethral level of the vagina. CONCLUSIONS: This study gives sonographic features of the pelvic floor in nulliparous women and in primigravidae after elective cesarean section. Data from the post-cesarean group can serve as reference values for further studies evaluating pelvic floor damage after various modi of vaginal delivery.     

The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery

OBJECTIVE: To describe the appearance and occurrence of abnormalities in the levator ani muscle seen on magnetic resonance imaging (MRI) in nulliparous women and in women after their first vaginal birth. METHODS: Multiplanar proton density magnetic resonance images were obtained at 0.5-cm intervals from 80 nulliparous and 160 vaginally primiparous women. These had been previously obtained in a study of stress incontinence, and half the primiparas had stress incontinence. All scans were reviewed independently by at least two examiners blinded to parity and continence status. RESULTS:No levator ani defects were identified in nulliparous women. Thirty-two primiparous women (20%) had a visible defect in the levator ani muscle. Defects were identified in the pubovisceral portion of the levator ani in 29 women and in the iliococcygeal portion in three women. Within the pubovisceral muscle, both unilateral and bilateral defects were found. The extent of abnormality varied from one individual to the next. Of the 32 women with defects, 23 (71%) were in the stress incontinent group. CONCLUSION: Abnormalities in the levator ani muscle are present on MRI after a vaginal delivery but are not found in nulliparas.