新生儿脊髓圆锥正常位置研究

Research for normal location of conus medullaris in neonates

目的确定我国新生儿脊髓圆锥的正常位置.方法超声检查89例胎龄31～46周新生儿腰骶部,确定脊髓圆锥末端和与其对应的椎体,标记脊髓圆锥末端位置,计算脊髓圆锥正常位置范围和平均位置,比较不同胎龄、性别新生儿脊髓圆锥位置,分析其相关因素.结果胎龄31周以上新生儿,脊髓圆锥正常位置范围约在L1(第1腰椎)中点到L3中点;平均位置约在L2中点.足月儿脊髓圆锥平均位置接近L2椎体的上缘,早产儿平均位置接近L2椎体的下缘,两者间差异有显著性(P＜0.05);不同性别脊髓圆锥位置差异无显著性.脊髓圆锥位置和胎龄、体重、头围、身高呈显著负相关.结论胎龄31周以上新生儿,脊髓圆锥平均位置约在L2中点,高于一般认为的L3水平;在达到足月前,脊髓圆锥随胎龄增加而上升,足月后在新生儿期脊髓圆锥位置无明显变化.

Objective To determine the normal location of conus medullaris in chinese neonates. Methods 89 neonates with gestational age from 31 weeks to 46 weeks underwent ultrasound examination for lumbosacral portion to determine the position of conus medullaris. The termination of conus medullaris was localized by its corresponding vertebral level and marked with numeral. The range of normal position and mean position were calculated. The positions were compared between those with different gestational ages and genders. The factors may influence the position of the conus medullaris were analyzed. Results The range of the termination of conus medullaris in neonates with gestational ages over 31 weeks is about from the midpoint of L1 to the midpoint of L3. The mean position was a little higher than the midpoint of L2. The mean position of the conus medullaris in the term infant approached the superior margin of L2 , and in the premature the inferior margin of L2 .There was a significant difference between above two positions （P 〈0.05）.There was no difference between those with different genders. The position of conus medullaris terminal had a negative correlation with gestational age,body weight,head circumference and body height. Conclusions The mean position of conus medullaris in neonates with gestational age over 31 weeks is little higher than the midpoint of L2, which is higher than the generally accepted level of L3. It ascends with increased gestational age before term and remains unchanged in the first month after birth.