A Study Of New Radiographic Feature Of L5 Laminae In The Youth With Lower Lumbar Disc Herniation

Objective: We assessed the condition of the lumbar laminae defect of L5 other than the defect of spina bifida in the crowd of different ages with lower lumbar disc herniation(LDH)in our study.And our study aimed to come up with the hypothesis that laminae defect of L5 maybe a radiographic feature in the young patients with lower LDH,and laminae defect was perhaps a relevant factor for patients to suffer from lower lumbar disc herniation prematurely.Methods: We analyzed the features of the laminae of L5 from the anteroposterior X-rays of lumbosacral spine in 342 patients suffered from lower LDH in our hospital from 2014.7 to 2015.12.We divided the patients into three groups depending on age: group of aged younger than 45(group A),group of 45 to 59(group B)and group of aged older than 59(group C).We measured the width of the unilateral laminae of L5 by drawing a line named “a” from the upper margin to the lower margin.Then the line “a” was extended downward to the bottom of laminae interval space to perform a new line named “b”,and the length of it was also measured.Furthermore,we assessed the condition of the laminae defect of L5 using the ratio “a/b” in each group.Besides,we analyzed the patients’ basic information in each group,such as the sex,the occupation type,the intensity of physical labor,the family history of LDH,the smoking history and the BMI.All data were analyzed by SPSS 20.0.Continuous variables were expressed as mean ± standard deviation and categorical variables as percentages.ANOVA was used for comparison of continuous variables,and the Pearson’s Chi-squared test was used for comparison of categorical variables.A P value <0.05 was considered statistically significant.Results: 1.The relevant factors such as the sex,the occupation type,the intensity of physical labor,the family history of LDH,the smoking history and the BMI have no statistical difference between any two groups of these three groups;2.The average ratio “a/b” in each group was: 0.47±0.06 in group A,0.51±0.06 in group B,and 0.52±0.06 in group C.The average ratio “a/b” of group A was significantly smaller both than group B and group C(P<0.05).However,there was no statistical difference of the average ratio “a/b” between group B and group C(P>0.05).Conclusions: The result of our study indicated the condition of laminae defect of L5 was more common in the young patients with lower LDH,and it may be a radiographic feature of lumbar in youth with lower LDH.Furthermore,laminae defect was a pathological basis for patients to suffer from lower lumbar disc herniation prematurely,and patients with the condition of laminae defect were possibly easier to leading to LDH.