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.

Cadmium Induced Apoptosis in MG63 Cells by Increasing ROS, Activation of p38 MAPK and Inhibition of ERK 1/2 Pathways.

BACKGROUND/AIMS: Cadmium (Cd) induces apoptosis in different kinds of cells, including osteoblasts, both in vivo and in vitro. However, little is known about the mechanisms by which Cd induces apoptosis. METHODS: In the present study, we used the human osteosarcoma cell line MG63, which has characteristics similar to human osteoblasts, as an in vitro model to determine the cellular mechanisms by which Cd induces apoptosis. RESULTS: We found that short-term exposure to CdCl2 induced apoptosis in MG63 cells. Furthermore, the incubation of cells with CdCl2 significantly increased the level of phosphorylated p38MAPK and significantly decreased the phosphorylation of ERK1/2 in a concentration-dependent manner. Additionally, the inhibition of the phosphorylation of p38 MAPK by SB202190 protected MG63 cells from Cd-induced apoptosis. The incubation of MG63 cells with the ERK1/2 inhibitor PD98059 significantly increased apoptosis in MG63 cells. CdCl2 also significantly increased the intracellular levels of ROS. N-acetylcysteine (NAC) significantly reduced ROS levels and reversed the effects of CdCl2 on MAPK signaling. CONCLUSION: Our results suggested that Cd induced apoptosis in MG63 cells by increasing ROS, activation of p38 MAPK and inhibition of ERK1/2 pathways.

[Pullout test in expansive unilateral open-door laminoplasty of the cervical spine with OsteoMed M3 plate and screws: the screw orientation matters].

OBJECTIVE: To study the impact of screw orientation on the pullout strength of OsteoMed M3 titanium screws in expansive unilateral open-door laminoplasty of the cervical spine. METHODS: Six fresh human cervical spine specimens were randomly numbered and OsteoMed M3 plate and screws were used for an expansive unilateral open-door laminoplasty. The screws were inserted in the lateral mass at different extraversion angles (0°, 30° and 45°). The maximum pullout strength was tested on the ElectroForce material testing machine. RESULTS: The maximum pullout strength was 81.60∓7.33 N, 150.05∓15.57 N, and 160.08∓17.77 N in extraversion angle 0°, 30°, and 45° groups, respectively. The maximum pullout strength was significantly less in extraversion angle 0° group than in 30° and 45° groups (P<0.05), but similar in the latter two groups. CONCLUSION: The pullout strength of the screws inserted at an extraversion angle over 30° provides stronger fixation than an angle of 0° in the unilateral open-door laminoplasty using OsteoMed M3 titanium plate and screws.

[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.