Examination of the Level of Conus Medullaris Termination Using Magnetic Resonance Imaging

Introduction: Recognition of the level of the conus medullaris termination (CMt) is of clinical importance for avoiding iatrogenic injuries during spinal anesthesia and lumbar puncture. Although CMt levels have been examined in a variety of studies, they vary in classical textbooks and literature studies. The aim of this study was to investigate the level of CMt and its correlation to gender, age, and body mass index (BMI) using magnetic resonance imaging (MRI) in healthy individuals and those with lumbar disc herniation. Methods: The lumbar MRIs of 341 subjects, including healthy individuals (F: 123, M: 68) and those with lumbar disc herniation (F: 105, M: 45), were retrospectively examined, and the CMt levels were determined. Results: It was found that CMt levels were most commonly located at upper 1/3 of the L1 vertebral body in both healthy individuals and those with disc herniation groups. No statistically significant difference was observed between the two groups evaluated. In addition, no significant mean level of CMt, weight, height, and BMI difference existed between the two groups. Conclusion: In the literature, the highest level of CMt is seen as being at the intervertebral disc between T11 and T12 vertebrae, while the lowest level of the CMt is seen as being at lower 1/3 of the L3 vertebral body. Consequently, we are of the opinion that the L3-4 or L4-5 intervertebral spaces should be preferred to lower the complication rate in procedures such as spinal anesthesia and lumbar puncture.