Effect of age and gender on the position of termination of the conus medullaris

Objective To investigate the effect of age and gender on the position of termination of the conus medullaris (CMT).Methods One thousand three hundred and thirty-nine patients aged 4-89 yr scheduled for lumbar magnetic resonance imaging examination were selected.The position of CMT was determined using Visart 1.5 T or Magnetom Trio 3.0 T magnetic resonance imaging instrument.Results Five hundred and ninety-four male patients and 745 female patients were enrolled in the study.There was no significant difference in the percentage of CMT located at the L2,3 intervertebral disc level between female (1.2％) and male (0.5％) patients (P＞0.05),and female patients had a lower mean CMT than male patients (P＜0.01).There was no correlation between age and mean CMT in patients aged ≤19 yr (P＞ 0.05).There was a positive correlation between age and mean CMT in female patients aged≤20 yr (r =0.076,P＜0.05),but there was no correlation between age and mean CMT in male patients aged ≤ 20 yr (P＞0.05 ).Conclusion Female patients have a lower mean CMT than male patients,and there is still a risk when performing spinal anesthesia,although the probability that CMT located at the L2,3 intervertebral disc level is low in female and male patients.The position of CMT is lower with increased age in adult female patients,but it is not related to age in adult male patients. Key words: Sex factors; Age factors; Spinal cord; Anatomy