Objective: To investigate the expression changes and the repair effect of mitogen and stress- activated protein kinase 1 (MSK1) on spinal cord injury (SCI) in rats. Methods: One hundred and twenty male Sprague Dawley (SD) rats (weighing 220-250 g) were used for the study, 70 of them were randomly divided into sham-operation group and SCI group ( n=35), the rats in SCI group were given SCI according to Allen's method, and the sham-operation group only opened the lamina without injuring the spinal cord; spinal cord tissue was collected at 8 hours, 12 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after invasive treatment, each group of 5 rats was used to detect the expression of MSK1 and proliferating cell nuclear antigen (PCNA) by Western blot assay. Another 20 SD rats were grouped by the same method as above ( n=10). In these rats, a negative control lentiviral LV3NC dilution was injected at a depth of approximately 0.8 mm at the spinal cord T 10 level. The results of transfection at 1, 3, 5, 7, and 14 days after injection were observed under an inverted fluorescence microscope to determine the optimal transfection time of the virus. The other 30 SD rats were randomly divided into group A with only SCI, group B with a negative control lentiviral LV3NC injected after SCI, and group C with MSK1 small interfering RNA (siRNA) lentivirus injected after SCI, with 10 rats each group. The Basso, Beatlie, Bresnahan (BBB) score of hind limbs was measured at 1, 3, 5, 7, and 14 days after treatment; spinal cord tissue collected at the optimal time point for lentivirus transfection was detected the expression changes of MSK1 and PCNA by Western blot and the localization by immunofluorescence staining of MSK1 and PCNA proteins. Results: Western blot assay showed that there was no significant changes in the expression of MSK1 and PCNA at each time points in the sham-operation group. In the SCI group, the expression of MSK1 protein was gradually decreased from 8 hours after injury to the lowest level at 3 days after injury, and then gradually increased; the expression change of PCNA protein was opposite to MSK1. The expression of MSK1 in SCI group was significantly lower than that in the sham-operation group at 1, 2, 3, and 5 days after injury ( P<0.05), and the expression of PCNA protein of SCI group was significantly higher than that of the sham-operation group at 8 hours and 1, 2, 3, 5, and 7 days after injury ( P<0.05). The fluorescence expression of both the SCI group and the sham-operation group has be found and peaked at 7 days. There was a positive correlation between fluorescence intensity and time in 7 days after transfection. With the prolongation of postoperative time, the BBB scores of groups A, B, and C showed a gradually increasing trend. The BBB score of group C was significantly lower than those of groups A and B at 5, 7, and 14 days after treatment ( P<0.05). After transfection for 7 days, Western blot results showed that the relative expression of MSK1 protein in group C was significantly lower than that in groups A and B ( P<0.05); and the relative expression of PCNA protein was significantly higher than that in groups A and B ( P<0.05). Immunofluorescence staining showed that MSK1 was expressed in the nuclei of the spinal cord and colocalized with green fluorescent protein, neuronal nuclei, and glial fibrillary acidic protein (GFAP). The relative expression area of MSK1 positive cells in group C was significantly higher than that in group B ( P<0.05), and the relative expression areas of PCNA and GFAP positive cells were significantly lower than those in group B ( P<0.05). Conclusion: Lentivirus-mediated MSK1 siRNA can effectively silence the expression of MSK1 in rat spinal cord tissue. MSK1 may play a critical role in the repair of SCI in rats by regulating the proliferation of glial cells.

Objective:To investigate the changes of paraspinal muscles in patients with degenerative lumbar scoliosis (DLS) and its correlation with lumbar kyphosis.Methods:The clinical data of 67 female patients with degenerative lumbar scoliosis, with an average of 65.4±5.6 years old (rang 52-83 years old), were retrospectively analyzed. There were 35 patients of DLS with lumbar degenerative kyphosis (LDK) in the DLS+LDK group, with an average of 64.60±5.40 years old (rang 52-75 years old), and 32 patients of lumbar scoliosis without lumbar kyphosis in the DLS group, with an average of 66.22±5.8 years old (rang 55-83 years old). The cross-sectional area (CSA) and the percentage of fat infiltration area (FIA%) of erector spinae and multifidus muscles of the 5 intervertebral disc levels (from L 1-2 to L 5S 1) were measured by MRI using Image J software (ver. 1.51 k, National Institutes of Health, USA). The curve direction, Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) were evaluated and recordedin both groups using an anteroposterior radiograph in the standing position, and the correlation between the changes of paraspinal muscles and these factors was analyzed. Results:The TLK, LL, and SVA values of the DLS+LDK group (11.85°±7.89°, -9.35°±8.70° and 70.16±76.94 mm) were higher than those of the DLS group (7.47°±5.06°, -26.46°±10.26° and 39.45±38.18mm) ( t=2.73, P=0.008; t=7.38, P<0.001; t=2.10, P=0.041). The TK, PI, and SS values of the DLS+LDK group (16.36°±13.52°, 42.49°±11.70° and 11.89°±10.03°) were lower than those of the DLS group (23.60°±10.23°, 49.38°±11.92° and 21.21°±8.28°) ( t=2.45, P=0.017; t=2.38, P=0.020; t=4.13, P<0.001). The differences of Cobb and PT were not statistically significant between the two groups. The cross-sectional areas of L 1-2, L 2-3, L 3-4 intervertebral disc levels of erector spinae of the DLS+LDK group (1 328.36±339.16 mm 2, 1 331.98±305.76 mm 2 and 12 53.58±275.86 mm 2) were lower than those of the DLS group (1 564.16±312.68 mm 2, 1 574.80±325.92 mm 2 and 1 427.18±278.82 mm 2) ( t=0.40, P=0.004; t=0.81, P=0.002; t=0.306, P=0.013). The cross-sectional areas of L 1-2, L 2-3, L 3-4, L 4-5 intervertebral disc levels of multifidus muscles of the DLS+LDK group (225.07±59.80 mm 2, 228.38±87.44 mm 2, 436.40±117.99 mm 2 and 666.55±184.13 mm 2) were lower than those of the DLS group (264.28±44.27 mm 2, 384.85±75.52 mm 2, 576.10±109.92 mm 2 and 801.52±145.83 mm 2) ( t=0.21, P=0.004; t=0.42, P<0.001; t=0.52, P<0.001; t=0.37, P=0.002). The differences of FIA% of erector spinae and multifidus muscles at all lumbar spine levels were not statistically significant between the two groups. The cross-sectional areas of L 1-2, L 2-3, L 3-4 intervertebral disc levels of erector spinae and L 1-2, L 2-3, L 3-4, L 4-5 intervertebral disc levels of multifidus muscles of the two groups were negatively correlated with LL values ( r=-0.37, P=0.002; r=-0.34, P=0.005; r=-0.21, P=0.049; r=-0.34, P=0.005; r=-0.61, P<0.001; r=-0.65, P<0.001; r=-0.55, P<0.001), and positively correlated with SS ( r=0.42, P<0.001; r=0.37, P=0.002; r=0.27, P=0.027; r=0.38, P=0.001; r=0.53, P<0.001; r=0.46, P<0.001; r=0.42, P<0.001). The cross-sectional areas of L 3-4 intervertebral disc levels of erector spinae and L 1-2, L 2-3 intervertebral disc levels of multifidus muscles of the two groups were positively correlated with PI ( r=0.25, P=0.039; r=0.33, P=0.006; r=0.35, P=0.004). There was no correlation between the FIA% of erector spinae and multifidus muscles at all lumbar spine levels and the sagittal and pelvic parameters in both groups. Conclusion:Paravertebral muscle atrophy is more obvious in patients with degenerative lumbar scoliosis with lumbar kyphosis, which may be related to the reduce of lumbar lordosis and sacral slope. Patients with lumbar scoliosis with a smaller PI are more likely to experience paravertebral atrophy and increased loss of lumbar lordosis, and ultimately leading to lumbar kyphosis.

Objective:To explore the clinical effect of the application of intraoperative psoas major intramuscular block therapy on the complications related to the approach after multi-segmental crenel lumbar interbody fusion (CLIF).Methods:All of 68 degenerative lumbar scoliosis patients who had received multi-segmental crenel lumbar interbody fusion during January 2020 and June 2020 were retrospectively reviewed. Patients were divided into two groups according to whether the psoas major muscle was treated with block therapy during the operation. The psoas muscle inblock group were filled with gel sponge infiltrated with a mixture of Betamethasone and lidocaine for local block therapy before closing the incision while that in the control group were not filled with gel sponge. There were 33 patients in the control group, 7 males and 26 females with an average of 65.8±7.1 years old (range: 54-81 years old); 35 cases in the block group, 9 males and 26 females with an average of 68.0±6.5 years old (range: 54-85 years old). The complications related to the approach (mainly includes pain, numbness in the front of the thigh, as well as psoas major, quadriceps muscle strength) were recorded respectively 1 day, 1 week, 1 month and 3 months after surgery. The main indicators of outcome including visual analog scale (VAS) of pain, the visual analog scale (VAS) of numbness, muscle strength of psoas major and quadriceps femoris, and the incidence of complications related to the approach were compared between the two groups of patients at different time points after surgery. The clinical outcomes were assessed using the Oswestry disability index (ODI), VAS for low back pain. The radiological outcome was evaluated with Cobb angles and sagittal balance parameters (sagittal vertical axis, SVA).Results:There were no significant differences in age, gender, body mass index (BMI), number of fusion segments, operation time, and intraoperative blood loss between the two groups. The incidence of approach-related complications was 17.1% in the block group and 39.4% in the control group, with statistically significant difference between the two groups ( χ2=4.177, P=0.041). The incidence of postoperative pain, numbness in the front of the thighs, and muscle strength of psoas major in the block group (11.4%, 14.3%) were lower than those in the control group (33.3%, 36.4%) ( χ2=4.740, P=0.029; χ2=4.416, P=0.036). And for numbness in the front of thigh, the block group (14.3) was lower than control group (21.2%), but no significant difference was shown between two groups ( χ2=0.561, P=0.454). However, there was no quadriceps weakness in either group. The VAS scores of painof the block group were lower than those of the control group at 1 day, 1 week, and 1 month after surgery, and the difference was statistically significant ( t=2.220, P=0.031; t=2.235, P=0.031; t=2.086, P=0.044). The difference at 3 months was not statistically significant ( t=0.385, P=0.701). The muscle strength of psoas major of the block group, meanwhile, was higher than those of the control group on the 1day and 1 week after surgery, the difference was statistically significant as well ( t=2.208, P=0.032; t=2.171, P=0.034). The difference at 1 and 3 months was not statistically significant ( t=0.923, P=0.359; t=1.437, P=0.160). No statistically significant differences were found in VAS scores of numbness at 1 day, 1 week, 1 month, and 3 months after surgery. Postoperative low back pain and lumbar spine function were significantly improved in both groups, and there was no statistical significance between the two groups. Coronal Cobb angle and sagittal balance were significantly improved in both groups after surgery, and there was no statistical significance between the two groups. Conclusion:Psoas major intramuscular block therapy can reduce the incidence of early postoperative complications of multi-segmental CLIF. Furthermore, it was found to be effective to alleviate anterior thigh pain within 1 month, and improve psoas major muscle weakness within 1 week.