An investigation of the conus medullaris termination level during the period of fetal development to adulthood

The spinal cord fills the length of the vertebral canal at the early period of intrauterine term. It is reported to extend to the level of the third lumbar vertebra at birth, because the vertebral column is growing more rapidly in the longitudinal direction than the spinal cord. The present investigation aimed to determine the changes in the termination level of conus medullaris (TLCM) from fetus to adulthood in a total of 285 individuals who had no defects in the central or peripheral nervous system, and were obtained from our Faculties of Medicine and Konya Maternity Hospital between 1992-1995. The age distribution was as follows: 36 fetuses, 20 prematures and 50 neonates, 51 children aged 1 to 7 years and 128 adults aged 15 to 68 years. In this study, for fetuses, prematures, neonates and children the TLCM was determined using ultrasonography. In addition, microdissection was used in fetuses to confirm the results obtained from the above technique. Also, magnetic resonance imaging was used in adults. During fetal life the end of the conus altered its levels from S3 to L3 vertebrae. The tip of the conus medullaris of the prematures and neonates ranged from LI to L3 vertebrae. The tip of the conus medullaris in the children lay between the Thi2 and L3 vertebrae, and in the adults it was between the ThJ2 and L2 vertebrae. There were slight differences between the prematures and neonates in terms of the TLCM. We concluded that there are differences in the TLCM between the age groups and therefore, especially in prematures and infants the determination of the tip of conus medullaris might be important for preventing postoperative neurological complications.