title: Level of conus medullaris termination in adult population analyzed by kinetic magnetic resonance imaging.
abstract: OBJECTIVE
  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.
authors.affiliation: 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.|Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
authors.forename: An
authors.initials: A
authors.lastname: Liu
authors.affiliation: 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.|Department of Orthopedics, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, 215006, China.
authors.forename: Kaixiang
authors.initials: K
authors.lastname: Yang
authors.affiliation: 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.|Department of Orthopaedic Surgery, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, China.
authors.forename: Daling
authors.initials: D
authors.lastname: Wang
authors.affiliation: 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.|Department of Orthopedics, Xinqiao Hospital, The Third Military Medical University, Chongqing, 400037, China.
authors.forename: Changqing
authors.initials: C
authors.lastname: Li
authors.affiliation: 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.|Department of Orthopaedic Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Ren
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
authors.forename: Shigui
authors.initials: S
authors.lastname: Yan
authors.affiliation: 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.
authors.forename: Zorica
authors.initials: Z
authors.lastname: Buser
authors.affiliation: 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.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D063405:Anatomic Variation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Age; Extension; Flexion; Gender; Kinetic magnetic resonance imaging; Level of conus medullaris termination