“胡桃夹”现象在正常儿童人群中的百分比及临床意义

Prevalence and clinical significance of nutcracker phenomenon of the left renal vein in children

目的探讨"胡桃夹"现象在正常儿童人群中出现的百分比及临床意义。方法回顾性分析2012年1月至2016年3月在重庆医科大学附属儿童医院放射科因非肾脏相关疾病行CT血管成像(computed tomographic angiography,CTA)检查的儿童腹部CTA影像及临床资料,共246例,男131例,女115例;年龄范围1月~<13.0岁,平均年龄(4.94±3.48)岁;所有儿童均除外左肾及左肾静脉相关疾病与变异,尿常规检查未见异常。按年龄分为7组:婴儿期(1月~<1.0岁)为1组,其他1.0~<13.0岁儿童以两岁为间隔分为6组。在CTA图像上,以同时具有左肾门部左肾静脉最大内径(D2)≥3倍腹主动脉与肠系膜上动脉间的左肾静脉内径(D1)以及腹主动脉与肠系膜上动脉之间的夹角(aortomesenteric angle,AMA)<45°为标准,判断是否存在"胡桃夹"现象,分析"胡桃夹"现象在正常儿童人群出现的百分比,以及AMA的变化。结果 246例中,34例(13.82%)出现"胡桃夹"现象,婴儿组出现百分比为0%,余下各组百分比依次为5.77%(3/52),12.20%(5/41),16.67%(8/48),18.75%(6/32),23.81%(5/21),28.00%(7/25),各年龄组"胡桃夹"现象出现的百分比存在显著的等级趋势性增高差异(χ~2=13.879,P<0.01),年龄越大出现百分比相对越高,而AMA随年龄的增大逐渐变小。结论 "胡桃夹"现象在正常儿童人群出现的百分比约为13.82%,其可以作为一种正常的解剖变异出现在一部分正常儿童中,正确认识这一现象可避免将其过度诊断为"胡桃夹"综合征。

Objective To determine the proportion of the children with nutcracker phenomenon, and explore the clinical significance of the phenomenon. Methods A retrospectively study was carried out on the children who underwent computed tomographic angiography （CTA） due to non-renal related diseases in our department of radiology from January 2012 to March 2016. The kids suffering from the diseases associated with left kidney, left renal vein or variation, or abnormal results of routine urine test were excluded. There were 246 children enrolled in this study, including 131 boys and 115 girls, at a mean age of 4.94 ± 3.48 years （ranging from 1 month to 13 years）. According to their age, the children were divided into 7 groups： the infant group （aged 1 month to 〈 1 year） , and 6 other groups with 2 years interval of age. The nutcracker phenomenon was defined as the maximum diameter of left renal vein in the renal helium （ D2 ） was 3 timeslarger than the diameter （ D1 ） of left renal vein between the abdominal aorta （AA） and superior mesenteric artery （SMA） and the aortomesenteric angle （AMA） between AA and AMA less than 45°. The proportion of children with the nutcracker phenomenon and the variation of AMA were analyzed. Results In the 246 subjects, nutcracker phenomenon was detected in 34 children （ 13.82% ） , with 0 % in the infant group, and 5.77% （3/52）, 12.20% （5/41）, 16.67% （8/48）, 18.75% （6/32）, 23.81% （5/21） and 28.00% （7/25） in order in the other 6 groups. There was a significant trend in the proportion of nutcracker phenomenon among the different aged group （ Chi square = 13. 879, P 〈 0. 001 ）. The occurrence rate of nutcracker phenomenon was increased with the age increase, while the angel of AMA become smaller. Conclusion Nutcracker phenomenon accounts for 13. 82% among normal children. It can be normal anatomical variation in some health children. The awareness of the phenomenon can avoid misdiagnosing it as nutcracker syndrome.