Sonographic diagnosis of the amniotic band syndrome.
Sonographic diagnosis of the amniotic band syndrome.
复制标题
羊膜带综合征的超声诊断。
DOI：
10.2214/ajr.156.3.1899757
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
R. A. Filly
中科院分区：
文献类型：
--
作者：
Doris J. Burton;R. A. Filly
羊膜带综合征（ABS），也被称为羊膜带断裂综合症或四肢-体壁综合症，是胎儿畸形的常见原因，估计每1200例活产婴儿中就有一例发生。畸形从轻微的畸形到严重的畸形，与出生后的生活不相容。尽管该综合征可出现多种畸形，但特征通常可提示诊断。超声检查人员应熟悉提示ABS的产前超声特征，并能够区分ABS与可能模仿ABS的发育异常。ABS的发病机制被认为是羊膜破裂，使胚胎或胎儿进入羊膜腔并接触羊膜的膜侧。然后，胎儿部位可能会被穿过颌离子间隙的纤维隔膜夹住。胎儿部位的缠绕是随机的，因此产生的斜线缺陷在分布上是非胚胎学的。胎儿的头、躯干和四肢可能单独受累，也可能同时受累。如果羊膜在妊娠早期破裂，在胚胎发生期间，绒毛膜腔的纤维间隔也可能干扰正常的胚胎发育，因此在患有ABS的胎儿中也可能发现典型的脑膨出或脐膨出等胚胎畸形。当颅部受累于ABS时，所产生的破坏性病变包括脑膨出，严重受累时，可能类似于无脑畸形。而“典型的”无脑儿的特征是完全没有颅骨，而ABS可能表现出部分颅骨的不对称保存，通常在颅底附近（图1）。典型的脑膨出发生在中线，而ABS的脑膨出发生在远离中线的地方。同样，当ABS发生面部裂隙时，它们往往发生在非胚胎分布中（图2）。当观察到这些不对称畸形之一累及颅面区域时，超声医师应怀疑ABS并寻找其他相关畸形。ABS的躯干畸形包括腹壁缺陷。肝外剥很少发生在孤立性胃裂中，但它通常发生在腹壁缺陷的ABS胎儿中，因此当看到它时，超声检查应怀疑ABS。ABS的躯干缺陷可能是广泛的，并累及胸部和腹壁（胃胸膜裂）。在这种畸形中，心脏、肝脏和肠道可能发生异位化（图3）。除了壁缺陷和器官外化外，ABS还常发生脊柱畸形。脊柱可表现为后凸、前凸、脊柱侧凸和/或明显的成角畸形（图4）。严重受累脊柱时，可能发生远端脊柱截肢（图5）。严重的脊柱畸形和腹壁缺损的结合是ABS的诊断。四肢经常涉及ABS，单独或与前面描述的畸形合并。不对称截肢可能涉及一个或多个手指或肢体的部分（图6）。羊膜带引起的局灶性收缩可能与远端淋巴水肿一起发生（图7）。截肢实际上是对ABS的诊断
The amniotic band syndrome (ABS), also known as the amniotic band disruption complex or limb-body wall complex, is a common cause offetal malformations, estimated to occur in one in 1200 live births [1]. The malformations mange from mild deformities to severe anomalies that are incompatible with postnatal life. Although a wide range of malformations can occur in this syndrome, characteristic features can often suggest the diagnosis. Sonographems should be familiar with features suggestive of ABS on antenatal sonography and be able to differentiate ABS from developmental anomalies that can mimic ABS. The pathogenesis of ABS is thought to be disruption of the amnion, allowing the embryo, or fetus, to enter the chomionic cavity and contact the chomionic side of the amnion. Fetal parts may then become entrapped by the fibrous septa that traverse the chomionic space. Entanglement of fetal parts is random and the slash defects so created are nonembryologic in distribution. The fetal head, trunk, and extremities may be involved individually or in combination. If the amnion is dismupted early in gestation, during the period of embryogenesis, the fibrous septa of the chorionic cavity may interfere with normal embryologic development also, so that embryologic malformations such as a classic encephalocele or omphalocele may also be found in a fetus with ABS [2]. When the calvaria is involved in ABS, the resultant destructive lesions include encephaloceles and, with severe involvement, may resemble anencephaly. Whereas “typical” anencephaly is characterized by complete absence of the calvaria, that which occurs in ABS may demonstrate asymmetric preservation of a portion of the calvaria, generally near the skull base (Fig. 1). Classic encephaloceles occur in the midline, whereas those seen with ABS occur away from the midline. Similarly, when facial clefts occur in ABS they tend to occur in nonembryologic distributions (Fig. 2). When one of these asymmetric malformations involving the craniofacial region is observed, the sonographer should suspect ABS and search for other associated malformations. Truncal deformities seen in ABS include abdominal wall defects. Whereas extemiorization of the liver rarely occurs in isolated gastmoschisis, it commonly occurs in fetuses with ABS and an abdominal wall defect, and it therefore should lead the sonogmapher to suspect ABS when seen. The defects of the torso in ABS may be extensive and involve the chest as well as the abdominal wall (gastropleuroschisis). In this deformity extemiomization of the heart, liver, and bowel may occur (Fig. 3). In addition to wall defects and exteriomization of organs, spinal deformities commonly occur in ABS. The spine may demonstrate kyphosis, lordosis, scoliosis, and/or marked angulation deformities (Fig. 4). With severe spinal involvement, amputation of the distal spine may occur (Fig. 5). The combination of severe spinal deformity and an abdominal wall defect is diagnostic of ABS. Extremities are frequently involved in ABS, alone or in combination with the malformations previously described. Asymmetric amputations may involve one or more digits or portions of an extremity (Fig. 6). Focal constrictions caused by the amniotic bands may occur with distal lymphedema (Fig. 7). An amputation virtually diagnostic of ABS is one with