Chinese Journal of Tissue Engineering Research ›› 2014, Vol. 18 ›› Issue (53): 8634-8640.doi: 10.3969/j.issn.2095-4344.2014.53.020

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Three dimensional test of lumbar canal volume in degenerative spondylolisthesis patients under physiological load

Xu Hong-da1, 2, Miao Jun2, Xia Qun2   

  1. 1Graduate School of Tianjin Medical University, Tianjin 300070, China
    2Department of Spinal Surgery, Tianjin Hospital, Tianjin 300211, China
  • Revised:2014-11-02 Online:2014-12-24 Published:2014-12-24
  • About author:Xu Hong-da, Studying for master’s degree, Graduate School of Tianjin Medical University, Tianjin 300070, China; Department of Spinal Surgery, Tianjin Hospital, Tianjin 300211, China
  • Supported by:

    the National Natural Science Foundation of China, No. 81371992.

Abstract:

BACKGROUND: Lumbar degenerative spondylolisthesis, typically characterized by the forward slippage of the superior vertebra of a lumbar motion segment, is a common spinal pathological condition in elderly individuals. Significant deformation and volume changes of the spinal canal can occur because of the vertebral slippage, but few data have been reported on these anatomic variations in lumbar degenerative spondylolisthesis patients. Whether to restore normal anatomy, such as reduction of the slippage and restoration of disc height, is still not clear in surgery.
OBJECTIVE: To observe the volume change of the spine canal and anatomic factors affecting the spine canal volume in lumbar degenerative spondylolisthesis patients.
METHODS: A total of 15 asymptomatic volunteers (normal group) at the age of 55±7 years and 15 patients with L4 spondylolisthesis (trial group) at the age of 54±6 years were recruited. Dual X-ray imaging system was combined with spiral CT. Lumbar three-dimensional reconstruction models were obtained from lumbar thin-section CT of subjects. In vivo lumbar vertebral motion during functional postures (supine, standing, flexion and extension) was observed using a dual fluoroscopic imaging technique. The volume of the spine canal was measured at each functional posture. Various anatomic parameters (disc height, cross-sectional area of the canal, left-right diameter of the canal, anterior-posterior diameter of the canal, slippage, posture, and intervertebral disc angle) that may potentially affect the canal volume were also measured.
RESULTS AND CONCLUSION: Spine canal volume was larger at supine and flexion postures than at stand and extension postures in both the normal and trial groups. Spine canal volume in the trial group was significantly lower than that in the normal group under all the four postures (P < 0.05). Pearson correlation analysis showed that L4-5 spine canal volume was strongly correlated with the L4-5 posterior disc height (γb = 0.80), correlated with the slippage percentage (γb = -0.61), and weakly associated with the L4-5 anterior disc height (γb = 0.28) and the disc angle (γb = -0.24). Above data indicated that the volume of spine canal is affected by multiple factors in patients with lumbar degenerative spondylolisthesis. Increased spine canal volume at supine and flexion positions may explain the clinical observations of relief of symptoms at these postures in lumbar degenerative spondylolisthesis patients. The reduction of slipped vertebral body, decrease of disc angle, intervertebral distraction, as well as decompression could be effective to increase the canal volume and to relieve clinical symptoms.

Key words: lumbar vertebrae, degenerative spondylolisthesis, spinal stenosis, dissection

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