Reconstruction of nerve root sheaths for sacral extradural spinal meningeal cysts with spinal nerve root fibers

This study analyzed the clinical characteristics and outcomes of sacral extradural spinal meningeal cysts with spinal nerve root fibers treated by reconstruction of the nerve root sheaths. The relationships between the cysts and spinal nerve root fibers were examined microscopically, the cysts were partially excised, and the defects were oversewn to reconstruct the nerve root sheaths. The Improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function. Thirty-eight patients were included in this study, with a mean age of 41.4±15.57 years. The mean IJOA score was 18.8±1.32 preoperatively and 19.6±0.65 postoperatively, which was a significant difference (t=?3.77, P=0.001). These results indicate a significant improvement in neurological function after surgery. The most significant improvement in neurological function was sensation (z=?2.86, P=0.004), followed by bowel/bladder function (z=?2.31, P=0.02).     

Ventral root afferent and dorsal root efferent fibres in dog and human lower sacral nerve roots.

Two pairs of wire electrodes were used to record single afferent action potentials from ventral roots and single efferent action potentials from dorsal roots of dogs and humans. A human lower sacral ventral root contained about 20 to 30% afferents among fibres with a diameter larger than 5 microns; a comparable ventral root of a dog contained about 1% afferents. Human S3, S4 and S5 dorsal roots contained 3, 18, and 20 to 30% efferent fibres respectively; a comparable dorsal root of the dog contained less than 1% efferent fibres. Primary and secondary muscle spindle afferents, Golgi tendon organ afferents, and afferents from the mechanoreceptors of the urinary bladder and anal canal mucosa were activated in a dog ventral root by pulling bladder and anal catheters. Their peak group conduction velocities were 82, 57, 71 and 18 m/s at 34 degrees C respectively. The dog afferents conducted more than 30% faster than did comparable human nerve fibres. By strongly pulling the bladder catheter, the static human dorsal root gamma 21-motoneurons increased their activity for about 7 s which in turn strongly increased the dorsal root spindle afferent activity for more than 10 min; the human static intrafusal gamma-motoneurons seemed to show cumulative properties.     

Group conduction velocities and nerve fibre diameters of alpha and gamma-motoneurons from lower sacral nerve roots of the dog and humans.

Single action potentials and their conduction times were recorded extracellularly from dog and human lower sacral nerve roots. Conduction velocity frequency distribution histograms were constructed and peaks of single extrafusal and intrafusal motoneuron distributions were identified. The electrophysiologically measured roots were removed and morphometrically analysed. Nerve fibre diameter frequency distribution histograms were constructed with respect to 3 myelin sheath thickness ranges, and peaks of single motoneuron group distributions were identified. The identified motoneuron classes, characterized by their group peak values of conduction velocity at about 36 degrees C and fibre diameter were: dog: intrafusal: gamma 22(23ms-1/4.8 microns),gamma 21(33/5.7), gamma 1 (43/6.7),gamma beta?(54/10.1) extrafusal: alpha 3(61ms-1/11.7 microns),alpha 2(72/13.6), alpha 11 (81/15.2), alpha 12(86/16.8),alpha 13(95/19) human: intrafusal: gamma 21(15ms-1/5.8 microns), gamma 1(20/6.8), gamma beta?(27/7.2) extrafusal: alpha 3(37ms-1/8.3 microns),alpha 2(50/10.2), alpha 1(60/13.1) The 60 (alpha 3) to 30% (alpha 1-motoneurons) higher conduction velocities in dogs as compared to humans seem to originate in the 40 (alpha 3) to 30% (alpha 1-motoneurons) larger nerve fibre diameters. However, the myelin sheath seemed to be 0.1 to 0.2 microns thinner in dogs than in humans. The pair-values "conduction velocity-fibre diameter" of the alpha and gamma-motoneuron groups were lying on different correlation curves in the velocity-diameter plane indicating structural and/or geometrical differences between alpha and gamma-motoneurons.     

Observations on the topographical relations of spinal nerve roots in the rat

The spinal cord along with the ventral and dorsal roots (C1-S4) were dissected out in 10 male and 5 female CF rats. The vertebral levels of origin and exit of the spinal nerve roots and termination of the spinal cord were recorded. It was observed that from the mid-cervical to the sacral region, the roots arose increasingly at cranial levels compared to their levels of exit. This disparity was at its maximum in the lumbar and sacral segments. The spinal cord terminated between the third and fourth lumbar vertebrae. There was no sexual dimorphism either at the level of termination of the cord or at the levels of origin and exit of origin and exit of the various nerve roots.     

骶神经电刺激对脊髓损伤大鼠肠黏膜机械屏障的保护作用

目的：观察骶神经电刺激对脊髓损伤大鼠肠黏膜机械屏障的保护作用。方法：56只Wistar大鼠分7组（n=8）：正常组、急性完全性脊髓损伤（SCI）组和骶神经电刺激组（按24、48、72h各8只）。进行内毒素测定;肠系膜淋巴结、肝脏、脾脏菌培养;肠道形态学观察;紧密连接蛋白zo-1的蛋白表达测定。结果：对照组肠黏膜不同程度损伤;肠道上皮细胞及细胞间连接破坏;内毒素血症和细菌移位明显。实验组肠黏膜得到改善,内毒素水平下降且细菌移位减少。ZO-1蛋白表达无统计学差异。对照组ZO-1的分布出现不同程度的散乱、排列不规则,实验组分布得到改善。结论：骶神经电刺激可促肠蠕动、排肠内容物、减少肠道菌群数量,保护肠黏膜上皮细胞及紧密连接的机械屏障,减少细菌移位和内毒素血症。     

Development of the axon membrane during differentiation of myelinated fibres in spinal nerve roots

Previous studies by a number of workers have shown that the axon membrane in normal mature myelinated fibres is highly differentiated, with the nodal axolemma exhibiting characteristics different to those of the internodal axolemma. However, the development of this axolemmal heterogeneity has not been previously explored. In the present study we used cytochemical methods to examine the development of nodal axolemma during the differentiation of myelinated fibres in rat spinal roots. The staining properties characteristic of normal nodal membrane appear in the axon, at gaps between Schwann cells, before the development of mature compact myelin or well defined paranodal axon--Schwann cell specializations close to the region of nodal axolemmal differentiation. These results are consistent with the hypothesis that the axon membrane differentiates into nodal and internodal regions before, or early in the process of, myelination, and suggest that the differentiation of the axon membrane may provide a signal demarcating the region to be covered by the myelin-forming cell.