Kinetic magnetic resonance imaging analysis of lumbar segmental motion at levels adjacent to disc herniation.
OBJECTIVE
A retrospective radiographic study was carried out to analyze the effect of lumbar disc herniation on the kinetic motion of adjacent segments.


METHODS
A total of 162 patients with low back pain or radicular pain in the lower limbs without a prior history of surgery were evaluated using kinetic magnetic resonance imaging. Translational motion, angular variation, and disc height were measured at each segment from L1-L2 to L5-S1. Other factors including the degree of disc degeneration, age, gender, and vertebral segment location were analyzed to determine any predisposing risk factors for segmental instability adjacent to disc herniations.


RESULTS
Spinal levels above the disc herniation exhibited, on average, a 6.4 % increase in translational motion per mm of disc herniation (P = 0.496) and a 21.4 % increase in angular motion per mm herniation (P = 0.447). Levels below the herniation demonstrated a 5.2 % increase in translational motion per mm of disc herniation (P = 0.428) and a decrease of 10.7 % in angular motion per mm (P = 0.726). The degree of disc degeneration had no significant correlation with adjacent level motion. Similarly, disc herniation was not significantly correlated with disc height at adjacent levels, although there was a significant relationship between gender and adjacent segment disc height.


CONCLUSIONS
Although disc height, translational motion, and angular variation are significantly affected at the level of a disc herniation, no significant changes are apparent in adjacent segments. Our results indicate that herniated discs have no effect on range of motion at adjacent levels regardless of the degree of disc degeneration or the size of disc herniation, suggesting that the natural progression of disc degeneration and adjacent segment disease may be separate, unrelated processes within the lumbar spine.
Department of Orthopaedic Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Lifeng
L
Lao
Department of Orthopaedic Surgery, University of California at Los Angeles (UCLA), Los Angeles, CA, USA.
Michael D
MD
Daubs
Department of Orthopaedic Surgery, University of California at Los Angeles (UCLA), Los Angeles, CA, USA.
Shinji
S
Takahashi
Department of Orthopaedic Surgery, University of California at Los Angeles (UCLA), Los Angeles, CA, USA.
Elizabeth L
EL
Lord
Department of Orthopaedic Surgery, University of California at Los Angeles (UCLA), Los Angeles, CA, USA.
Jeremiah R
JR
Cohen
Department of Orthopaedic Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Guibin
G
Zhong
Department of Orthopaedic Surgery, Keck School of Medicine of USC, 1520 San Pablo, HCT Suite 2000, Los Angeles, CA, 90033, USA. Jeffrey.Wang@med.usc.edu.
Jeffrey C
JC
Wang
D000293:Adolescent; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D018450:Disease Progression; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications / Q000503:physiopathology; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000503:physiopathology*; D007700:Kinetics; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
Adjacent segment degeneration; Disc herniation; Kinematic analysis; Kinetic magnetic resonance imaging; Lumbar spine