Dynamic evaluation of the cervical spine by kinematic MRI in patients with cervical spinal cord injury without fracture and dislocation.

BACKGROUND: The pattern of changes in the cervical spine and the spinal cord and their dynamic characteristics in patients with cervical spinal cord injury without fracture and dislocation remain unclear. This study aimed to evaluate the dynamic changes in the cervical spine and spinal cord from C2/3 to C7/T1 in different positions by using kinematic magnetic resonance imaging in patients with cervical spinal cord injury without fracture and dislocation. This study was approved by the ethics committee of Yuebei People's Hospital. METHODS: Using median sagittal T2-weighted images for 16 patients with cervical spinal cord injury without fracture and dislocation who underwent cervical kinematic MRI, the anterior space available for the cord, spinal cord diameter, posterior space available for the cord from C2/3 to C7/T1, and Muhle's grade were determined. The spinal canal diameter was calculated by adding the anterior space available for the cord, spinal cord diameter, and posterior space available for the cord. RESULTS: The anterior space available for the cord, posterior space available for the cord, and spinal canal diameters at C2/3 and C7/T1 were significantly higher than those from C3/4 to C6/7. Muhle's grades at C2/3 and C7/T1 were significantly lower than those at the other levels. Spinal canal diameter was lower in extension than in the neutral and flexion positions. In the operated segments, significantly lesser space was available for the cord (anterior space available for the cord + posterior space available for the cord), and the spinal cord diameter/spinal canal diameter ratio was higher than those in the C2/3, C7/T1, and non-operated segments. CONCLUSION: Kinematic MRI demonstrated dynamic pathoanatomical changes, such as canal stenosis in different positions, in patients with cervical spinal cord injury without fracture and dislocation. The injured segment had a small canal diameter, high Muhle's grade, low space available for the cord, and high spinal cord diameter/spinal canal diameter ratio.

[Clinical application of expansive unilateral open-door laminoplasty of the cervical spine with OsteoMed M3 plate and screws].

OBJECTIVE: To introduce a new technique using OsteoMed M3 titanium plate and screws for fixation of the posterior elements in the open position after expansive unilateral open-door laminoplasty and evaluate its clinical effect. METHODS: Sixteen patients with multilevel cervical disc herniation and canal stenosis were treated with an expansive unilateral open-door laminoplasty using OsteoMed M3 plate and screws, and the follow-up period lasted for over 6 months. RESULTS: Most of the patients had marked neurological improvement after the surgery. The mean Japanese Orthopaedic Association (JOA) score of the patients increased significantly from 9.06-/+2.380 (range 5 to 13) before surgery to 13.63-/+1.408 (range 11 to 16) at the final follow-up (P<0.005), with a mean recovery rate of 57.5%. One patient without postoperative neurological improvement underwent an additional anterior multilevel corpectomy. Bone fusion of the surgical lamina was achieved in all the cases without canal stenosis. CONCLUSION: Unilateral open-door laminoplasty with OsteoMed M3 titanium plate and screw fixation can effectively maintain the expansion of the spinal canal and resist closure while preserving the spinal alignment and stability. This modified technique is easy to perform and is associated with a low complication rate.