Evaluation of cervical degenerative spondylolisthesis using Kinematic MRI

Evaluation of cervical degenerative spondylolisthesis using Kinematic MRI

Two recent studies by Jeffrey C Wang, Permsak Paholpak and Zorica Buser looked at how cervical degenerative spondylolisthesis can alter the kinematic of the cervical spine. Here, the authors give an insight into their studies and the outcomes gained from it.

Cervical degenerative spondylolisthesis is a pathological condition caused by degeneration of the cervical spine. Disc degeneration and facet joint degeneration are considered to be the important precursors of cervical degenerative spondylolisthesis. The prevalence of cervical degenerative spondylolisthesis has been reported between 3.9 per cent and 20 per cent. The diagnostic criteria of cervical degenerative spondylolisthesis is not clearly defined, usually the translation of more than 2mm in anterior or posterior direction is used in diagnosis.

Thoracic inlet parameters (TI), such as T1 slope, Thoracic Inlet Angle (TIA), and Neck Tilt Angle (NT), together with cervical sagittal balance parameters, such as Sagittal Vertical Axis (SVA), are the radiographic parameter, which have been evaluated in cervical degenerative diseases (see Figure 1).

Figure 1: Thoracic inlet parameters and cervical sagittal vertical axis measurements on kinematic MRI.

T1 slope is one of the novel thoracic parameters that can reflect cervical sagittal balance and might have similar importance as the pelvic incidence in the lumbo-sacral spine. Jun et al. studied T1 slope in cervical degenerative spondylolisthesis in neutral position MRI and found that T1 slope was one of the predisposing factors in the onset of anterolisthesis (anterior translation). Furthermore, cervical degenerative spondylolisthesis patients had larger T1 slope than the control patient group, and worse post-operative outcome after cervical laminoplasty.

Several studies hypothesised that patients with high T1 slope had a higher chance of post-operative cervical kyphosis and a need for an increased posterior paraspinal neck muscle neck function to maintain horizontal gaze and minimize the energy expenditure from head positioning.

Drs. Wang, Paholpak and Buser studied TI and cervical sagittal balance parameters in 52 patients (33 anterolisthesis) with cervical degenerative spondylolisthesis using kinematic MRI, in order to better understand the effect of these parameters on cervical degenerative spondylolisthesis pathogenesis. Kinematic MRI (kMRI) is a 0.6 Tesla MRI scanner (Upright Multi Position, Fornar Corp, New York, NY, USA) which can perform weight-bearing multi-positional examination. For cervical spine kMRI, the patients were seated in an upright weight-bearing neutral (0°), flexion (40°), and extension (-20°) positions.

The results showed that patients with retrolisthesis (posterior translation) had tended to have a larger T1 slope and cervical lordosis angle than the cervical degenerative spondylolisthesis patients with anterolisthesis, in neutral, flexion, and extension position (see Figure 2).

 

Figure 2: Thoracic inlet parameters and cervical sagittal vertical axis of anterolisthesis cervical degeneration spondylolisthesis (both anterolisthesis and retrolisthesis) in three positions. * is a statistically significant difference (p-value <0.05). For C2-7 angle, the negative value represnets the lordosis angle.

From our results, we hypothesised that T1 slope, C2-7 angle and cervical SVA might have a significant effect on the direction of translation in cervical degenerative spondylolisthesis. In retrolisthesis, the larger T1 slope and cervical lordosis the more severe might be the etiology or consequence of posterior translation of the cervical spine.

In our studies we also looked at the aspect of the kinematic changes in Space Available for Cord (SAC), motion (both translation and angular motion), and disc degeneration at the spondylolisthesis and adjacent levels (caudad and cephalad level). In order to evaluate the SAC and motion, we used a MRAnalyzer (TruMRI Corp., Bellflower, CA, USA) (see Figure 3). We evaluated the disc degeneration according to Suzuki et al. classification (see table 1).

Our results demonstrated that cervical degenerative spondylolisthesis altered normal cervical spine kinematics. In non-degenerated cervical spine, the translational motion decreased from C3-4 to C6-7 level. In our study, the spondylolisthesis level had more translation motion than its cephalad level. Furthermore, the spondylolisthesis level also had the narrowest SAC. The retrolisthesis level had narrower SAC than the anterolisthesis level. For disc degeneration, the cephalad level had the least disc degeneration and the disc degeneration at the spondylolisthesis level in patients with retrolisthesis was more advanced than in the anterolisthesis.

Table 1: Grading of cervical disc degeneration.

 

 

 

 

 

 

Figure 3: Motions and space available for cord analysis. Translation motion; the difference between extension and flexion motion value was used for each level. Angular motion; the difference between extension and flexion motion value was used for each level.

 

 

 

 

 

 

 

 

In conclusion, cervical degenerative spondylolisthesis altered the kinematic of the cervical spine. The retrolisthesis had more disc degeneration at the listhesis level, larger T1 slope, larger cervical lordosis angle and narrower SAC than the anterolisthesis.

 

References

  1. Paholpak P, Nazareth A, Barkoh K, and others. Space Available for Cord, Motion, and disc degeneration at the adjacent segments level of degenerative cervical spondylolisthesis using kinematic MRI. J Clin Neurosci. 2017.
  2. Paholpak P, and others. Kinematic evaluation of cervical sagittal balance and thoracic inlet alignment in degenerative cervical spondylolisthesis using kinematic magnetic resonance imaging. Spine J. 2017.
  3. Jun HS, Kim JH, Ahn JH, and others. T1 slope and degenerative cervical spondylolisthesis. Spine (Phila Pa 1976). 2015;40(4):E220-6.
  4. Suzuki A, Daubs MD, Inoue H, and others. Prevalence and motion characteristics of degenerative cervical spondylolisthesis in the symptomatic adult. Spine (Phila Pa 1976). 2013;38(17):E1115-20.
  5. Daffner SD, Xin J, Taghavi CE, and others. Cervical segmental motion at levels adjacent to disc herniation as determined with kinetic magnetic resonance imaging. Spine (Phila Pa 1976). 2009;34(22):2389-94.

Authors:

  • Jeffrey C. Wang, Orthopaedic Spine Service, Co-Director USC Spine Center, Professor of Orthopaedic Surgery and Neurosurgery USC Spine Center, Los Angeles, USA
  • Permsak Paholpak, Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
  • Zorica Buser, Assistant Professor of Research Orthopaedic Surgery, Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, USA
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