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BACKGROUND: Spinal-pelvic sagittal alignment is important for the diagnosis and treatment of degenerative lumbar spondylolisthesis. However, the current study of the spine-pelvic sagittal alignment in patients with degenerative lumbar spondylolisthesis is limited to the standing position. There is no relevant report on the spine-pelvic sagittal alignment under the sitting position. OBJECTIVE: To analyze imaging data of sitting-standing spine-pelvic sagittal alignment in patients with degenerative lumbar spondylolisthesis, and to detennine the sagittal alignment of spine change in degenerative lumbar spondylolisthesis patients from standing position to sitting position. METHODS: Totally 44 patients with degenerative lumbar spondylolisthesis (12 males, 32 females; age, 50-84 years) were enrolled from Tianjin Hospital from March to September 2019. All patients took X-rays of the spine in standing and sitting positions. Through the hospital image archiving and communication system, spinal and pelvic parameters were measured, including pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, and sagittal vertical axis. The parameters were compared between standing posture and sitting posture. By using Pearson's correlation test, differences of relationship between spinal and pelvic parameters in standing versus sitting position were discussed. This study was approved by the Ethics Committee of Tianjin Hospital. RESULTS AND CONCLUSION: (1) When moving from standing to sitting pos~ion, in 44 degenerative lumbar spondylolisthesis patients, pelvic tilt increased [(21.3±1 0.1 )°, (34.0±1 0.4)°, P < 0.001 [; sacral slope decreased [(31.5±8.6)°, (20.8±12. 7)°, P < 0.001]; lumbar lordosis reduced [(40.9±14.6)°, (25.8±15.0)°, P < 0.001]; sagittal vertical axis increased [(43.0±43.4), (75.0±34.8) mm, P < 0.001]; pelvic incidence and thoracic kyphosis did not significantly changed (P > 0.05). (2) Whether standing or sitting position, lumbar lordosis was correlated with other parameters (P < 0.05). When changing from standing to sitting position, the correlation between sacral slope and sagittal vertical axis disappeared (P > 0.05), but lumbar lordosis was also correlated with sagittal vertical axis (P < 0.05). (3) When the degenerative lumbar spondylolisthesis patients change from standing position to sitting position, the sagittal configuration of spine pelvis shows that the pelvis rotates back around the bilateral femoral heads; the pelvis shows a backward leaning state; the physiological curvature of lumbar spine becomes shallow; and the sagittal balance axis of spine moves forward. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is still difficult to construct tissue-engineered anulus fibrosus scaffolds which have bionic structure, suitable biodegradability and good biocompatibility. OBJECTIVE: To fabricate bionic biodegradable scaffolds with polycaprolactone (PCL) and polydioxanone (PDS) and evaluate the feasibility as a tissue-engineered annulus fibrosus scaffold. METHODS: Five groups of scaffolds at different PCL/PDS proportions were prepared by malt spinning technique: PCL, PCL/PDS70/30, PCL/PDS50/50, PCL/PDS30/70, and PDS groups. Scanning electron microscopy was used to observe the structure and measure the fiber diameter and pore size of these prepared scaffolds. The mechanical properties and contact angle of the scaffolds were measured. The in vitro and in vivo biodegradation of the scaffolds were observation by in vitro simulation and subcutaneous implantation. The expression of inflammatory factors interleukin-1β and tumor necrosis factor-a in the biodegraded tissues was detected. Human Wharton's jelly mesenchymal stem cells were cultured for 7 days. Cell viability and proliferation was determined by live/dead cell staining. This study was approved by the Medical Ethics Committee of Tianjin Hospital, China on March 2, 2016. RESULTS AND CONCLUSION: Scanning electron microscopy results showed that the thickness of the scaffold fibers was unifonn and lhe angle between fibers was 60o. The mechanical properties analysis showed that the tensile and compressive modulus of the PDS group was the lowest, which did not meet the mechanical requirements of the anulus fibrosus; the tensile and compressive modulus in the PCL group was the highest, and those in the PCL/PDS70/30 and PCL/PDS50/50 group were moderate. Hydrophilicity test showed that higher PDS proportion led to better hydrophilicity. Biodegradation test showed that the biodegradation of pure PDS and PCL/PDS30/70 was too fast, that of PCL was too slow, and that of PCL/PDS70/30 and PCL/PDS50/50 was appropriate. Analysis of inflammatory response around the biodegraded tissue showed that higher proportion of PCL in the scaffold resulted in more severe inflammatory response. CCK-8 and live/dead cell staining showed that human Wharton's jelly mesenchymal stem cells had good proliferative activity and high survival rate in the PCL/PDS70/30, PCL/PDS50/50, and PCL/PDS30/70 groups. These results suggest that scaffolds in the PCL/PDS70/30 and PCL/PDS50/50 groups can simulate the structure of natural annulus fibrosus, have appropriate biodegradability, excellent mechanical properties and good biocompatibility, which make it a suitable candidate for tissue-engineered annulus fibrosus scaffold. [ABSTRACT FROM AUTHOR]

Objective To analyze the value of mini-open approach beside costodiaphragmatic recess in thoracolumbar spine surgery. Methods This approach was applied in 31 anterior thoracolumbar spine surgeries, including 22 men and 9 women, with a mean age of 41 years old (range, 26-58 yrs). The diagnosis were burst fractures in 27 cases (T12 level in 12 cases and L1 level in 15 cases) and disc herniations with osteochondrosis in 4 cases. An antero-lateral 10-15 (average is 12) cm incision was performed, then the 11th rib was resected and the extraperitoneal space below diaphragma was disconnected. The pleura fold was identified beneath the rib bed, so the gap beside the costdiaphragmatic recess was entered through an in- cision beyond the fold. The diaphragm and medial arcuate ligament were clipped and vertebral body from T11 to L2 were ex- posed. Results The lateral side of T11 to L2 vertebral body was sufficiently exposed in all the 31 patients. In 26 patients, the pleura fold was beyond the bed of the 11th rib, so the 11th intercostals vessel and nerve were exposed and protected, and the costodiaphragmatic recess was reached through the superior border of the 12th rib. Laceration of pleura occurred in 4 cases af- ter it was sutured, but the extra-pleura approach could still be used after repairing without invading into thorax. Fixation and fusion were performed from T11 to L2. Complications include intercostals nerve pain were seen in 3 cases, which resolved with conservative treatment. Conclusion The mini-open approach beside costodiaphragmatic recess can be used in anterior thoraclumbar spine surgery with sufficient explosion and minimum injury in which thoracic cavity. [ABSTRACT FROM AUTHOR]

Objective To investigate the feasibility of construction of tissue engineering nucleus pulposus by combining the novel silk fibroin porous scaffold with PKH26 labeled rabbit nucleus pulposus cells. Methods Rabbit nucleus pulposus cells were isolated and cultured, then the passage 1 nucleus pulposus cells were stained with safranin O and type II collagen immunohistochemical staining. The isolated rabbit nucleus pulposus cells were labeled with PKH26. MTT assay was used for examining the proliferation of the nucleus pulposus cells before and after labeling. Labeled cells were inoculated in the scaffold, cultured for 4 days and then the cell-scaffold complexes were implanted subcutaneously into nude mice. After 12 weeks of in vivo culture, the cell-scaffold complexes were detected by in vivo imaging technology, H & E staining, toluidine blue staining, safranin O staining and collagen type II immunohistochemical staining. Results Safranin O staining and type II collagen immunohistochemical staining of the passage 1 nucleus pulposus cells were positive. The fluorescence intensity of labeled cell was distributed, and the difference of OD value of nucleus pulposus cells was not statistically significant before and after labeling (P > 0.05). The in vivo imaging technique showed a strong fluorescencea in porous scaffold. H&E staining of cell-scaffold complexes showed that the scaffolds were filled with a large number of nucleus pulposus cells and large amount of extracellular matrix. Toluidine blue staining, safranin O staining and type II collagen immunohistochemical staining were positive, and large amount of extracellular matrix was secreted around the cells. Conclusion The new silk fibroin porous scaffold with rabbit nucleus pulposus cells in vivo culture formed nucleus pulposus like tissue, which can be used for construction of tissue engineering nucleus. [ABSTRACT FROM AUTHOR]

In order to prepare low price and high active catalyst for biomass tar pyrogasification, based on the rich oxygen-containing species in lignite, a kind of novel catalyst was prepared by loading nickel on Shenli lignite char via ion-exchange. The effects of solution pH and carbonization temperature on the physic-chemical properties of catalyst was studied. The research determined the optimum operation condition of Ni/SLC catalyst. Then the catalyst was used in two-stage moving-bed gasification of corn cob in quartz tube reactor. The influence of catalyst on gas yield and carbon balance was investigated. The results showed that, the catalyst prepared in the pH of 11 at 650 °C reached the maximum SS.A of 266.3 m²/g and the nickel particles dispersed quite well in the catalyst with the NCS of 5.0 nm. It effectively improved tar decomposition at 650 °C under inert atmosphere and produced a tar-free syngas in a yield of 43.9 mmoL/g, which were 3.3 times of the total gas yield without catalyst. The gasification of coal tar with steam was thorough. The gas yield were 85.1 mmol/g, the H2 yield were 61.9 mmol/g, which were 72.7% of the total gas yield. So the Ni/SLC catalyst was suitable for the gasification of biomass. [ABSTRACT FROM AUTHOR]

Objective To investigate the application of PKH26 fluorescent labeling on nucleus pulposus cells isolated from bovine coccyx disc, and to provide nucleus pulposus tissue engineering with traceable nucleus pulposus cells by PKH26 fluorescence labelling. Methods Nucleus pulposus primary cells were isolated from the nucleus pulposus tissue detached from bovine coccyx disc by enzymatic digestion, and observed under the inverted microscope. Safranin O, toluidine blue and type II collagen immunocytochemistry methods used to stain for passage one generation cells. Nucleus pulposus cells were labeled with PKH26 fluorescence in accordance with the instructions. The cell activity, fluorescence intensity at d0, d14 and d28 of culture, characteristics of proliferation and the expression of gene in labeled cells were assessed. Results Isolated nucleus pulposus cells amounted to (1.56 ± 0.35) x 106/g. Under the inverted microscope, primary cells adhered at the 4 th day of culture, grew in groups, and covered the bottom of culture flask at the 13 th day. Both primary cells and the P1 generation cells were chondrocyte-like morphology. The staining of safranin O, toluidine blue and type II collagen immunocytochemistry for P1 generation of nucleus pulposus cells showed positive results. The cell activity before and after PKH26 labeling showed more than 95%, and the fluorescence intensity at d0, d14 and d28 performed a decreasing trend, but still showed detect strong fluorescence at d28. There were no significant differences in proliferation and the expression of gene (collagen type I and II, aggrecan) before and after cell labeling (P > 0.05). Conclusion As the seed cells of tissue engineering, nucleus pulposus cells isolated from bovine coccyx can reach a satisfactory number and maintain cartilage-like phenotype, and no changes shown in the biological characteristics after labeling. PKH26 labeled nucleus pulposus cells are suitable for the traceable cells in vivo study. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of percutaneous cement discoplasty (PCD) and percutaneous cement interbody fusion (PCIF) on spinal stability by in vitro biomechanical tests., Methods: Biomechanical test was divided into intact (INT) group, percutaneous lumbar discectomy (PLD) group, PCD group, and PCIF group. Six specimens of L 4, 5 (including vertebral bodies and intervertebral discs) from fresh male cadavers were taken to prepare PLD, PCD, and PCIF specimens, respectively. Before treatment and after the above treatments, the MTS multi-degree-of-freedom simulation test system was used to conduct the biomechanical test. The intervertebral height of the specimen was measured before and after the axial loading of 300 N, and the difference was calculated. The range of motion (ROM) and stiffness of the spine in flexion, extension, left/right bending, and left/right rotation under a torque of 7.5 Nm were calculated., Results: After axial loading, the change of intervertebral height in PLD group was more significant than that in other three groups ( P <0.05). Compared with INT group, the ROM in all directions significantly increased and the stiffness significantly decreased in PLD group ( P <0.05). Compared with INT group, the ROM of flexion, extension, and left/right rotation in PCD group significantly increased and the stiffness significantly decreased ( P <0.05); compared with PLD group, the ROM of flexion, extension, and left/right bending in PCD group significantly decreased and the stiffness significantly increased ( P <0.05). Compared with INT group, ROM of left/right bending in PCIF group significantly decreased and stiffness significantly increased ( P <0.05); compared with PLD group, the ROM in all directions significantly decreased and the stiffness significantly increased ( P <0.05); compared with PCD group, the ROM of flexion, left/right bending, and left/right rotation significantly decreased and stiffness significantly increased ( P <0.05)., Conclusion: Both PCD and PCIF can provide good biomechanical stability. The former mainly affects the stiffness in flexion, extension, and bending, while the latter is more restrictive on lumbar ROM in all directions, especially in bending and rotation.

Objective: To investigate the effectiveness of microscope assisted anterior lumbar discectomy and fusion (ALDF) and mobile microendoscopic discectomy assisted lumbar interbody fusion (MMED-LIF) for lumbar degenerative diseases., Methods: A clinical data of 163 patients with lumbar degenerative diseases who met the criteria between January 2018 and December 2020 was retrospectively analyzed. Fifty-three cases were treated with microscope assisted ALDF (ALDF group) and 110 cases with MMED-LIF (MMED-LIF group). There was no significant difference between the two groups in terms of gender, age, disease type, surgical segments, preoperative visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), intervertebral space height, lordosis angle, and spondylolisthesis rate of the patients with lumbar spondylolisthesis ( P >0.05). The operation time, intraoperative blood loss, and hospital stay of the two groups were recorded. The effectiveness was evaluated by VAS scores of low back pain and leg pain and ODI. Postoperative lumbar X-ray films were taken to observe the position of Cage and measure the intervertebral space height, lordosis angle, and spondylolisthesis rate of the patients with lumbar spondylolisthesis., Results: The operations were successfully completed in both groups. The operation time, intraoperative blood loss, and hospital stay in ALDF group were less than those in MMED-LIF group ( P <0.05). The patients in both groups were followed up 12-36 months, with an average of 24 months. The VAS scores of low back pain and leg pain and ODI after operation were lower than those before operation in the two groups, and showed a continuous downward trend, with significant differences between different time points ( P <0.05). There were significant differences between two groups in VAS score of low back pain and ODI ( P <0.05) and no significant difference in VAS score of leg pain ( P >0.05) at each time point. The improvement rates of VAS score of low back pain and ODI in ALDF group were significantly higher than those in MMED-LIF group ( t =7.187, P =0.000; t =2.716, P =0.007), but there was no significant difference in the improvement rate of VAS score of leg pain ( t =0.556, P =0.579). The postoperative lumbar X-ray films showed the significant recovery of the intervertebral space height, lordosis angle, and spondylolisthesis rate at 2 days after operation when compared with preoperation ( P <0.05), and the improvements were maintained until last follow-up ( P >0.05). The improvement rates of intervertebral space height and lordosis angle in ALDF group were significantly higher than those in MMED-LIF group ( P <0.05). There was no significant difference in the reduction rate of spondylolisthesis between the two groups ( t =1.396, P =0.167). During follow-up, there was no loosening or breakage of the implant and no displacement or sinking of the Cage., Conclusion: Under appropriate indications, microscope assisted ALDF and MMED-LIF both can achieve good results for lumbar degenerative diseases. Microscope assisted ALDF was superior to MMED-LIF in the improvement of low back pain and function and the recovery of intervertebral space height and lordosis angle.

Objective: To observe the histological structure and cytocompatibility of novel acellular bone matrix (ACBM) and to investigate the feasibility as a scaffold for bone tissue engineering., Methods: Cancellous bone columns were harvested from the density region of 18-24 months old male canine femoral head, then were dealt with high-pressure water washing, degreasing, and decellularization with Trixon X-100 and sodium deoxycholate to prepare the ACBM scaffold. The scaffolds were observed by scanning electron microscope (SEM); HE staining, Hoechst 33258 staining, and sirius red staining were used for histological analysis. Bone marrow mesenchymal stem cells (BMSCs) from canine were isolated and cultured with density gradient centrifugation; the 3rd passage BMSCs were seeded onto the scaffold. MTT test was done to assess the cytotoxicity of the scaffolds. The proliferation and differentiation of the cells on the scaffold were observed by inverted microscope, SEM, and live/dead cell staining method., Results: HE staining and Hoechst 33258 staining showed that there was no cell fragments in the scaffolds; sirius red staining showed that the ACBM scaffold was stained crimson or red and yellow alternating. SEM observation revealed a three dimensional interconnected porous structure, which was the microstructure of normal cancellous bone. Cytotoxicity testing with MTT revealed no significant difference in absorbance (A) values between different extracts (25%, 50%, and 100%) and H-DMEM culture media (P > 0.05), indicating no cytotoxic effect of the scaffold on BMSCs. Inverted microscope, SEM, and histological analysis showed that three dimensional interconnected porous structure of the scaffold supported the proliferation and attachment of BMSCs, which secreted abundant extracellular matrices. Live/dead cell staining results of cell-scaffold composites revealed that the cells displaying green fluorescence were observed., Conclusion: Novel ACBM scaffold can be used as an alternative cell-carrier for bone tissue engineering because of thoroughly decellularization, good mircostructure, non-toxicity, and good cytocompatibility.

Objective: To fabricate a novel composite scaffold with acellular demineralized bone matrix/acellular nucleus pulposus matrix and to verify the feasibility of using it as a scaffold for intervertebral disc tissue engineering through detecting physical and chemical properties., Methods: Pig proximal femoral cancellous bone rings (10 mm in external diameter, 5 mm in internal diameter, and 3 mm in thickness) were fabricated, and were dealed with degreasing, decalcification, and decellularization to prepare the annulus fibrosus phase of scaffold. Nucleus pulposus was taken from pig tails, decellularized with Triton X-100 and deoxycholic acid, crushed and centrifugalized to prepare nucleus pulposus extracellular mtrtix which was injected into the center of annulus fibrosus phase. Then the composite scaffold was freeze-dryed, cross-linked with ultraviolet radiation/carbodiimide and disinfected for use. The scaffold was investigated by general observation, HE staining, and scanning electron microscopy, as well as porosity measurement, water absorption rate, and compressive elastic modulus. Adipose-derived stem cells (ADSCs) were cultured with different concentrations of scaffold extract (25%, 50%, and 100%) to assess cytotoxicity of the scaffold. The cell viability of ADSCs seeded on the scaffold was detected by Live/Dead staining., Results: The scaffold was white by general observation. The HE staining revealed that there was no cell fragments on the scaffold, and the dye homogeneously distributed. The scanning electron microscopy showed that the pore of the annulus fibrosus phase interconnected and the pore size was uniform; acellular nucleus pulposus matrix microfilament interconnected forming a uniform network structure, and the junction of the scaffold was closely connected. The novel porous scaffold had a good pore interconnectivity with (343.00 +/- 88.25) microm pore diameter of the annulus fibrosus phase, 82.98% +/- 7.02% porosity and 621.53% +/- 53.31% water absorption rate. The biomechanical test showed that the compressive modulus of elasticity was (89.07 +/- 8.73) kPa. The MTT test indicated that scaffold extract had no influence on cell proliferation. Live/Dead staining showed that ADSCs had a good proliferation on the scaffold and there was no dead cell., Conclusion: Novel composite scaffold made of acellular demineralized bone matrix/acellular nucleus pulposus matrix has good pore diameter and porosity, biomechanical properties close to natural intervertebral disc, non-toxicity, and good biocompatibility, so it is a suitable scaffold for intervertebral disc tissue engineering.

Objective: To evaluate the influence of PKH26 labeling on the biological function of the goat nucleus pulposus cells and the biological function of seeded cells in nude mice by in vivo imaging techonology., Methods: Primary nucleus pulposus cells were isolated by enzymatic digestion from the nucleus pulposus tissue of the 1-year-old goat disc. The nucleus pulposus cells at passage 1 were labeled with PKH26 and the fluorescent intensity was observed under the fluorescence microscopy. The labeled cells were stained with toluidine blue and collagen type II immunocytochemistry. The cells viability and proliferation characteristics were assessed by trypan blue staining and MTT assay, respectively. Real-time fluorescent quantitative PCR was used to detect the gene expressions of collagen types I and II, and aggrecan. The fluorescent intensity and scope of the nucleus pulposus cells-scaffold composite in vivo for 6 weeks after implanting into 5 6-week-old male nude mice were measured by in vivo imaging technology., Results: Primary nucleus pulposus cells were ovoid in cell shape, showing cluster growth, and the cells at passage 1 showed chondrocyte-like morphology under the inverted phase contrast microscope. The results of toluidine blue and collagen type II immunocytochemistry staining for nucleus pulposus cells at passage 1 were positive. The fluorescent intensity was even after labeling, and the cell viability was more than 95% before and after PKH26 labeling. There was no significant difference in cell growth curve between before and after labeling (P > 0.05). The real-time fluorescent quantitative PCR showed that there was no significant difference in gene expressions of collagen types I and II, and aggrecan between before and after labeling (P > 0.05). Strong fluorescence in nucleus pulposus cells-scaffold composite was detected and by in vivo imaging technology., Conclusion: The PKH26 labeling has no effect on the activity, proliferation, and cell phenotype gene expression of the nucleus pulposus cells. A combination of PKH26 labeling and in vivo imaging technology can track the biological behavior of the cells in vivo.

Objective: To observe the chondrogenic differentiation of adipose-derived stem cells (ADSCs) by co-culturing chondrocytes and ADSCs., Methods: ADSCs and chondrocytes were isolated and cultured from 8 healthy 4-month-old New Zealand rabbits (male or female, weighing 2.2-2.7 kg). ADSCs and chondrocytes at passage 2 were used. The 1 mL chondrocytes at concentration 2 x 10(4)/mL and 1 mL ADSCs at concentration 2 x 10(4)/mL were seeded on the upper layer and lower layer of Transwell 6-well plates separately in the experimental group, while ADSCs were cultured alone in the control group. The morphology changes of the induced ADSCs were observed by inverted phase contrast microscope. The glycosaminoglycan and collagen type II synthesized by the induced ADSCs were detected with toluidine blue staining and immunohistochemistry staining. The mRNA expressions of collagen type II, aggrecan, and SOX9 were detected with real-time fluorescent quantitative PCR., Results: ADSCs in the experimental group gradually became chondrocytes-like in morphology and manifested as round; while ADSCs in the control group manifested as long spindle in morphology with whirlool growth pattern. At 14 days after co-culturing, the results of toluidine blue staining and immunohistochemistry staining were positive in the experimental group, while the results were negative in the control group. The results of real-time fluorescent quantitative PCR indicated that the expression levels of collagen type II, aggrecan, and SOX9 mRNA in the experimental group (1.43 +/- 0.07, 2.13 +/- 0.08, and 1.08 +/- 0.08) were significantly higher than those in the control group (0.04 +/- 0.03, 0.13 +/- 0.04, and 0.10 +/- 0.02) (P < 0.05)., Conclusion: ADSCs can differentiate into chondrocytes-like after co-culturing with chondrocytes.