The Percentage Of Nutcracker Phenomenon In Normal Children And Its Clinical Significance

Purpose: To explore the percentage of nutcracker phenomenon(NCP)appearing in normal children and its clinical significance.Materials and methods: The imaging and clinical data of the hospitalized children,who initially underwent computed tomographic angiography(CTA)without kidney-related diseases in the Department of Radiology at Children's Hospital of Chongqing Medical University from January 2012 to March 2016,were retrospectively analyzed.A total of 246 cases(131 males and 115 females)with mean age of(4.94 ± 3.48)years(range from 1 month to 13 years)were enrolled and children with left renal or left renal vein related diseases and variations,retroperitoneal occupying lesions and abnormal uric convention were excluded.The children were divided into 7 groups according to the age: infants(1 month-1 year)independently and the rest(1-13 years)assigned to 6 groups at two yeas interval.By using CTA,when the angle between the AA and the SMA was less than 45 degrees and the ratio of internal diameter(D2)of left renal vein(LRV)proximal to the left kidney to the diameter(D1)between abdominal aorta(AA)and superior mesentery(SMA)was larger than or equal to three,NCP was diagnosed and the percentage in normal children and the variation of the aortomesenteric angle(AMA)were analyzed.Results: Nutcracker phenomenon was detected in 34(13.82%)children,with 0% in the infancy group.The remaining groups were 5.77%(3/52),12.20%(5/41),16.67%(8/48),18.75%(6/32),23.81%(5/21)and 28%(7/25)respectively.There was a statistically significant relationship between age and frequency of nutcracker phenomenon(?2=13.879,P<0.01).The incidence of nutcracker phenomenon increases and AMA gradually become smaller with the increase of age.Conclusion: The percentage of NCP in normal children is about 13.82%,there is a growing tendency with age,the phenomenon can be seen as a normal anatomical variation in some normal children.Correctly recognizing this phenomenon could avoid the over diagnosis of nutcracker syndrome.