Flexion/Extension Cervical Magnetic Resonance Imaging: A Potentially Useful Tool for Decision-Making in Patients with Symptomatic Degenerative Cervical Spine.

OBJECTIVE: To evaluate the reliability and usefulness of cervical flexion/extension magnetic resonance imaging (MRI) as a tool for decision-making regarding treatment of symptomatic cervical spondylosis. METHODS: We prospectively collected demographic, clinical, and flexion/neutral/extension MRI data for consecutive 24 patients who had presented with symptomatic cervical degenerative disease. From the survey responses, we analyzed the agreement between clinical interpretation and judgment when neutral MRI (nMRI) versus flexion/extension MRI (fMRI/eMRI) had been provided. Additionally, the mean cervical canal diameter (MCCD), as measured by 2 independent radiologists, was tested for intra- and interobserver reliability. The differences in MCCD between nMRI, fMRI, and eMRI and the correlation with the qualitative assessment by spine surgeons were also evaluated. RESULTS: Using nMRI only, 16.7%-33.3% of the surgical candidates were missed. Neurosurgeons were significantly more likely to use a posterior approach and instrumentation when fMRI/eMRI studies were available compared with nMRI studies alone. More levels had undergone surgery when the providers had been presented with the fMRI/eMRI studies. The raters expressed a preference for the use of fMRI/eMRI in their future practice. The MCCD was significantly different when measured on the nMRI studies compared with the fMRI/eMRI studies and correlated with the qualitative assessments. CONCLUSIONS: Flexion/extension MRI studies were useful for assessing patients with cervical degenerative spine disorders regarding the surgical indication, direction of the approach, and use of multilevel instrumentation, especially for patients with early cervical myelopathy.

Development and Characterisation of an in vitro Model of Wallerian Degeneration.

Following peripheral nerve injury, a sequence of events termed Wallerian degeneration (WD) takes place at the distal stump in order to allow the regenerating axons to grow back toward the target organs. Schwann cells (SCs) play a lead role in this by initiating the inflammatory response attracting macrophages and immune cells, as well as producing neurotrophic signals that are essential for nerve regeneration. The majority of existing research has focused on tools to improve regeneration, overlooking the critical degeneration phase. This is also due to the lack of in vitro models recapitulating the features of in vivo WD. In particular, to understand the initial SC response following injury, and to investigate potential interventions, a model that isolates the nerve from other systemic influences is required. Stem cell intervention has been extensively studied as a potential therapeutic intervention to augment regeneration; however, data regarding their role in WD is lacking. Thus, in this study we describe an in vitro model using rat sciatic nerve explants degenerating up to 14 days. Characterisation of this model was performed by gene and protein expression for key markers of WD, in addition to immunohistochemical analysis and electron microscopy. We found changes in keeping with WD in vivo: upregulation of repair program protein CJUN, downregulation of myelin protein genes and subsequent disorganisation and breakdown of myelin structure. As a means of testing the effects of stem cell intervention on WD we established indirect co-cultures of human adipose-derived mesenchymal stem cells (AD-MSC) with the degenerating nerve explants. The stem cell intervention potentiated neurotrophic factors and Cjun expression. We conclude that our in vitro model shares the main features of in vivo WD, and we provide proof of principle on its effectiveness to study experimental approaches for nerve regeneration focused on the events happening during WD.