Department of Obstetrics and Gynecology, Shiga University of Medical Science, Ohtsu, Japan.
Tohoku J Exp Med. 2011 Oct;225(2):85-7. doi: 10.1620/tjem.225.85.
Sirenomelia is a rare congenital syndrome that is characterized by the anomalous development of the caudal region of the body. The anomalies include bilateral renal agenesis or dysgenesis and the absence of the sacrum and other vertebral defects. Sirenomelia is also known as "mermaid syndrome," because of the one lower extremity. It is usually associated with severe oligohydramnios, and its prognosis is very poor due to pulmonary hypoplasia that is caused by severe oligohydramnios. The patient referred to our hospital at the gestational age of 27 weeks with fetal growth restriction and oligohydramnios. The estimated fetal body weight was 970 g (-4.9 S.D.). We could identify only one-side extremities, and could not identify kidneys by ultrasound examination. Because a single lower extremity and severe oligohydramnios are characteristics of the sirenomelia, we suspected sirenomelia. However, it could not be confirmed by ultrasound examination because of oligohydramnios. Therefore, we performed three-dimensional helical computed tomography (3D-CT), which is more accurate than ultrasound examinations for prenatal diagnosis of skeletal abnormalities. 3D-CT revealed an only one lower extremity. At 36 weeks and 5 days of gestation, the woman went into spontaneous labor and delivered an infant weighing 870 g. The infant has a single upper extremity and a single lower extremity. We provided supportive care for the neonate, who however died 1 hour 36 minutes after birth from severe respiratory distress. In summary, we report the correct diagnosis of sirenomelia with 3D-CT in the late second trimester.
并腿畸形综合征是一种罕见的先天性综合征，其特征为身体尾部区域的异常发育。异常包括双侧肾缺如或发育不良以及骶骨缺失和其他脊柱缺陷。并腿畸形综合征也被称为“美人鱼综合征”，因为下肢只有一条。它通常与严重羊水过少有关，由于严重羊水过少导致的肺发育不全，其预后非常差。该患者在妊娠 27 周时因胎儿生长受限和羊水过少转诊至我院。估计胎儿体重为 970 克（-4.9SD）。我们只能识别出一侧肢体，超声检查无法识别肾脏。由于单侧下肢和严重羊水过少是并腿畸形的特征，我们怀疑是并腿畸形。然而，由于羊水过少，超声检查无法确诊。因此，我们进行了三维螺旋 CT（3D-CT）检查，该检查对骨骼异常的产前诊断比超声检查更准确。3D-CT 显示只有一条下肢。在妊娠 36 周零 5 天，孕妇自然分娩，娩出一名体重 870 克的婴儿。婴儿有单侧上肢和单侧下肢。我们为新生儿提供了支持性护理，但新生儿因严重呼吸窘迫在出生后 1 小时 36 分钟死亡。总之，我们在妊娠中期后期通过 3D-CT 正确诊断了并腿畸形。
