Two-dimensional magnetic resonance neurography in neurotmesis of the left sciatic nerve A case report

Magnetic resonance neurography （MRN） is used to determine traumatic changes within nervous trunks. A 21-year-old male was treated for neurotmesis of the left sciatic nerve. At 41 days after micro-neurosurgery, two-dimensional MRN （2-D MRN） was performed with plain and contrast scans in the left injured sciatic nerve. More than 2 years after trauma, 2-D MRN images were collected to re-examine the left sciatic nerve. Results from the first 2-D MRN examination revealed a swollen left sciatic nerve. Furthermore, TlWl revealed a local nodule with slightly high intensity, and T2WI revealed hyperintensity. The nodule was significantly enhanced. Upon 2-D MRN re-examination more than 2 years after injury, the injured left sciatic nerve trunk was thinner, and the nodule margin in the left sciatic trunk was clearer. The supero-inferior diameter was enlarged by 2 mm compared with previous films. The degree of enhancement became weaker in the nodule. 2-D MRN revealed continuity, traumatic neuroma, and atrophy of the injured sciatic nerves in detail. Thin-slice technique was crucial for this method, as well as fat-suppressed and blood flow-suppressed imaging.

Evaluation of biodegradable electric conductive tube-guides and mesenchymal stem cells

AIM: To study the therapeutic effect of three tubeguides with electrical conductivity associated to mesenchymal stem cells(MSCs) on neuro-muscular regeneration after neurotmesis.METHODS: Rats with 10-mm gap nerve injury were tested using polyvinyl alcohol(PVA), PVA-carbon nanotubes(CNTs) and MSCs, and PVA-polypyrrole(PPy). The regenerated nerves and tibialis anterior muscles were processed for stereological studies after 20 wk. The functional recovery was assessed serially for gait biomechanical analysis, by extensor postural thrust, sciatic functional index and static sciatic functionalindex(SSI), and by withdrawal reflex latency(WRL). In vitro studies included cytocompatibility, flow cytometry, reverse transcriptase polymerase chain reaction and karyotype analysis of the MSCs. Histopathology of lung, liver, kidneys, and regional lymph nodes ensured the biomaterials biocompatibility. RESULTS: SSI remained negative throughout and independently from treatment. Differences between treted groups in the severity of changes in WRL existed, showing a faster regeneration for PVA-CNTs-MSCs(P < 0.05). At toe-off, less acute ankle joint angles were seen for PVA-CNTs-MSCs group(P = 0.051) suggesting improved ankle muscles function during the push off phase of the gait cycle. In PVA-PPy and PVA-CNTs groups, there was a 25% and 42% increase of average fiber area and a 13% and 21% increase of the "minimal Feret's diameter" respectively. Stereological analysis disclosed a significantly(P < 0.05) increased myelin thickness(M), ratio myelin thickness/axon diameter(M/d) and ratio axon diameter/fiber diameter(d/D; g-ratio) in PVA-CNT-MSCs group(P < 0.05). CONCLUSION: Results revealed that treatment with MSCs and PVA-CNTs tube-guides induced better nerve fiber regeneration. Functional and kinematics analysis revealed positive synergistic effects brought by MSCs and PVA-CNTs. The PVA-CNTs and PVA-PPy are promising scaffolds with electric conductive properties, bio- and cytocompatible that might prevent the secondary neurogenic muscular atrophy by improving the reestablishment of the neuro-muscular junction.