An Liu1,2, Kaixiang Yang1,3, Daling Wang1,4, Changqing Li1,5, Zhiwei Ren1,6, Shigui Yan2, Zorica Buser7, Jeffrey C Wang1. 1. Department of Orthopaedic Surgery, Keck School of Medicine, Elaine Stevely Hoffman Medical Research Center, University of Southern California, HMR 710, 2011 Zonal Ave, Los Angeles, CA, 90033, USA. 2. Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China. 3. Department of Orthopedics, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, 215006, China. 4. Department of Orthopaedic Surgery, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, China. 5. Department of Orthopedics, Xinqiao Hospital, The Third Military Medical University, Chongqing, 400037, China. 6. Department of Orthopaedic Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China. 7. Department of Orthopaedic Surgery, Keck School of Medicine, Elaine Stevely Hoffman Medical Research Center, University of Southern California, HMR 710, 2011 Zonal Ave, Los Angeles, CA, 90033, USA. zbuser@usc.edu.
Abstract
PURPOSE: To investigate the change of conus medullaris termination (CMT) level in neutral, flexion and extension positions and to analyze the effects of age and gender on the CMT level. METHODS: The midline sagittal T2-weighted kinetic magnetic resonance imaging (kMRI) study of 585 patients was retrospectively reviewed to identify the level of CMT. All patients were in an upright position. A straight line perpendicular to the long axis of the cord was drawn from the tip of the cord and then subtended to the adjacent vertebra or disk space. The CMT level was labeled in relation to the upper, middle and lower segments of adjacent vertebra or disk space and assigned values from 0 to 12 [0 = upper third of T12 (T12U), and 12 = upper third of L3 (L3U)]. All parameters were collected for neutral, flexion and extension positions. RESULTS: The level of CMT had the highest incidence (17.61%) at L1 lower (L1L) in neutral position, 17.44% at L1 upper (L1U) in flexion, and 16.92% at L1 middle (L1M) in extension with no significant differences among three positions (p > 0.05) in weight-bearing status. Moreover, the level of CMT was not correlated with age (p > 0.05). In terms of gender, the level of CMT was lower in women than in men in neutral position, flexion, and extension (p < 0.05). Furthermore, when divided by age in decades, there was a significant difference between females and males in the age group 60-69 years in neutral, flexion and extension position, respectively (p < 0.05). CONCLUSIONS: The level of CMT in the neutral position was in accordance with previous cadaveric and supine-position MRI studies, and it did not change with flexion and extension. Women had lower CMT level than men, especially in the older population. This information can be very valuable when performing spinal anesthesia and spinal punctures.
PURPOSE: To investigate the change of conus medullaris termination (CMT) level in neutral, flexion and extension positions and to analyze the effects of age and gender on the CMT level. METHODS: The midline sagittal T2-weighted kinetic magnetic resonance imaging (kMRI) study of 585 patients was retrospectively reviewed to identify the level of CMT. All patients were in an upright position. A straight line perpendicular to the long axis of the cord was drawn from the tip of the cord and then subtended to the adjacent vertebra or disk space. The CMT level was labeled in relation to the upper, middle and lower segments of adjacent vertebra or disk space and assigned values from 0 to 12 [0 = upper third of T12 (T12U), and 12 = upper third of L3 (L3U)]. All parameters were collected for neutral, flexion and extension positions. RESULTS: The level of CMT had the highest incidence (17.61%) at L1 lower (L1L) in neutral position, 17.44% at L1 upper (L1U) in flexion, and 16.92% at L1 middle (L1M) in extension with no significant differences among three positions (p > 0.05) in weight-bearing status. Moreover, the level of CMT was not correlated with age (p > 0.05). In terms of gender, the level of CMT was lower in women than in men in neutral position, flexion, and extension (p < 0.05). Furthermore, when divided by age in decades, there was a significant difference between females and males in the age group 60-69 years in neutral, flexion and extension position, respectively (p < 0.05). CONCLUSIONS: The level of CMT in the neutral position was in accordance with previous cadaveric and supine-position MRI studies, and it did not change with flexion and extension. Women had lower CMT level than men, especially in the older population. This information can be very valuable when performing spinal anesthesia and spinal punctures.
Entities:
Keywords:
Age; Extension; Flexion; Gender; Kinetic magnetic resonance imaging; Level of conus medullaris termination
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