ABSTRACT
BACKGROUND: A large amount of literature has been published on the vertebral pedicle morphology at thoracolumbar segments in adults,but little is known about the morphology of pedicles in adolescents, especially in Asian populations. Adolescent spine disorders are increasing and there are few precise morphological studies. OBJECTIVE: To investigate the anatomy of lumbar vertebrae of adolescents aged 12-15 years in Inner Mongolia, provide detailed information for pedicle screw placement, determine the safe and appropriate screw size, and provide data reference for screw size design. METHODS: The normal chest and lumbar CT data of 65 adolescents aged 12-15 years in Inner Mongolia were collected and divided into two groups, 31 cases of 12-13 years old, and 34 cases of 14-15 years old. The raw data of the thoracic and lumbar vertebrae images scanned continuously were imported into Mimics 21.0 for analysis and measurement in DICOM format. Pedicle width, pedicle height, transverse diameter, longitudinal diameter, pedicle length, pedicle outer declination, pedicle maximum external angle, pedicle head inclination, and pedicle area were measured. RESULTS AND CONCLUSION: (1) The L1-L4 pedicle width in the two groups was less than pedicle height, and pedicle width and pedicle height at L5were similar. The pedicle width determined the screw diameter, which was larger in males than in females. (2) In 12-13 years old, the screw length at L1-L5 was between 40-45 mm. In 14-15 years old, the screw length was between 40-45 mm at L1-L4 , and 45-50 mm at L5 (3) The laws of the two groups were the same. The transverse diameter of spinal canal was significantly larger than longitudinal diameter of spinal canal (P<0.05), and there was no significant difference between men and women. (4) The transverse pedicle angle: In 12-13 years old L1-L2 had small change,L2-L5 gradually increased; in 14-15 years old, L1-L5 gradually increased; it is larger in males than in females in both groups. (5) Maximum transverse pedicle angle: The two groups had the same law. L1-L5 gradually increased, and decreased with age. There was no significant difference between left and right sides and sexes. There was significant difference among different ages (P<0.05). (6) The sagittal pedicle angle: The in 12-13 years old, 30-80; in 14-15 years old, 00-50. The value decreased with age, and there was significant difference between men and women in L3-L4 (P<0.05). (7) Pedicle area: The two groups had the same rules. L1-L5 gradually increased, and L4-L5 had a clear trend of change. (8) Analysis of pedicle parameters showed that the size of the screws in the lumbar vertebrae of normal adolescents was suitable for the clinician to grasp the anatomy of the lumbar spine and improve the accuracy of clinical operation.