Adjacent segment degeneration after single- and double-level cervical total disc replacement: a cohort with an over 12-year follow-up.

PURPOSE: To characterize the change of adjacent segment degeneration (ASD) after cervical total disc replacement (CTDR) with more than 12-year follow-up, and identify the risk factors for ASD. METHOD: This process included 75 patients underwent CTDR from February 2004 to December 2012, with the follow-up of 151.9 ± 36.0 (m). The artificial disc included ProDisc-C, Prestige-LP and Mobi-C. ASD was followed up at 1 week, 6 months, 1 year, 2 years, 5 years, 10 years after CTDR and at the endpoint of June 2022. The radiographic measurements were cervical mobility, intervertebral disc height (IDH), cervical lordosis and balance status. The complications were implant migration, subsidence and heterotopic ossification (HO). RESULTS: Cervical mobility in adjacent segments, IDH and lordosis showed no statistical differences between ASD and NASD group. Balance status, subsidence and migration showed no relationship with ASD. Postoperative ASD increased at 6 m and especially between 6 m to 2y. There was no difference between the incidence of upper ASD and lower ASD all the time and few ASD-related reoperation. The majority of adjacent segments were C4/5 (33.6%) and C6/7 (34.2%), and ASD of C5/6 had the highest incidence (61.5%). Cox regression showed ASD was not related to the types of prosthesis or operated numbers. Generalized estimating equations (GEE) analysis showed severe HO had a higher (2.68 times) probability to suffer from ASD. CONCLUSIONS: After over 12-year follow-up of CTDR, the occurrence of ASD and HO had temporal synchronization. ASD was not merely a natural progression but with the pathological process such as HO.

Study on the crystallization behavior and conformation adjustment scale of poly(lactic acid) in the terahertz frequency range.

The observed properties of crystalline polymers are determined by their internal structure, which in turn is the result of their different crystallization behaviors. Here, we investigate the crystallization behavior of poly(lactic acid) (PLA) by terahertz time-domain spectroscopy (THz-TDS) at varied temperatures. We find that the changes in the chain packing and conformation of PLA are characterized by THz spectroscopy. Combining X-ray diffraction (XRD) and infrared spectroscopy (IR), we attributed the blue-shift of the THz peak to the tightness of the chain packing, while its absorption enhancement is caused by the conformation transition. The effects of chain packing and chain conformation on the characteristic peak are phased. Furthermore, absorption discontinuities of the characteristic peaks of PLA crystallized at different temperatures are observed, which originated from differences in the degree of conformational transition caused by different thermal energies. We find that the crystallization temperature at which the absorption mutation of PLA occurs corresponds to the temperature at which the motion of the segment and molecular chain is excited, respectively. At these two temperatures, PLA exhibits different scales of conformational transitions leading to stronger absorption and larger absorption changes at higher crystallization temperatures. The results demonstrate that the driving force of PLA crystallization is indeed from changes in chain packing and chain conformation, and the molecular motion scale can also be characterized by THz spectroscopy.

Perioperative risk factors related to complications of lumbar spine fusion surgery in elderly patients.

PURPOSE: To analyze the perioperative risk factors related to lumbar spine fusion surgery in elderly patients. METHODS: 202 elderly patients (age range 77-92 years old) who have underwent lumbar spinal fusion surgeries between January 2019 and June 2021 were retrospectively investigated. Information of age, sex, comorbidity, fixation segments, operation time, surgical blood loss and perioperative complications during hospitalization were collected. Risk factors for complications were analyzed. Student's t-test, chi-square test, Mann-Whitney U­test and multivariate generalized linear models were used. RESULTS: In this study, 31 patients presented complications (15.3%) in these elderly patients with an average age of 79.1 years, including 1 patient with intraoperative complication and 30 patients with postoperative complications; and 2 out of 31 patients (1%) died. The elderly patients were divided into group A (24 patients) with major postoperative complications and group B (178 patients) without major postoperative complications. Major postoperative complications were significantly associated with age (univariate analysis, t = 3.92, P < 0.001; multivariate analysis, OR = 1.323, 95%CI 1.126-1.554, P = 0.001), but not significantly associated with other factors tested (sex, comorbidity, fixation segments, operation time, surgical blood loss). Then 173 patients (range 77-81 years) were selected and the rate of major postoperative complications of each age from 78 to 81 years was compared with that of 77 years patients, respectively. We found that the ratios of complications at 80 years (OR = 10.000, P = 0.019) and 81 years (OR = 10.000, P = 0.009) were higher than the ratio at 77 years. CONCLUSIONS: Although with great progress of medical technology, increasing age was still the independent risk factor for major postoperative complications in elderly patients undergoing lumbar spinal fusion surgery. As for the incidence of major postoperative complications, 80 and 81 years old patients was 10 folds higher than that of 77 years old patients, reminding us to pay more attention to 80 years old and even older patients.

Study of Crystallinity and Conformation of Poly(lactic acid) by Terahertz Spectroscopy.

During crystallization, conformational changes are often accompanied by the formation of interactions. Terahertz (THz) spectroscopy exhibits strong responses to the crystalline poly(lactic acid) (PLA). Therefore, we estimate the relative crystallinity and investigate the effect of conformational transition on the vibration of PLA by THz spectroscopy. By comparing with the results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC), the validity of THz spectroscopy to calculate crystallinity is verified. Furthermore, the peak intensity of PLA at 2.01 THz increases with crystallinity. Combined with Fourier transform infrared spectroscopy (FTIR), the vibrational intensity of PLA at 2.01 THz is highly correlated with the contribution of gt conformation, showing a linear relationship. In addition, the vibrational peak of PLA also reflects the interchain interactions. We believe that the increase in peak intensity with increasing crystallinity originates from the effect of the dipole-dipole interactions between the carbonyl groups. Our study demonstrates the ability of THz spectroscopy to estimate the crystallinity of PLA, and the peak at 2.01 THz shows conformational and interaction sensitivities.

Terahertz spectroscopy for interpreting the formation and hierarchical structures of silk fibroin oligopeptides.

Determining the configuration and conformation of peptides is crucial for interpreting their structure-property relationships. In this work, we present nondestructive terahertz time-domain spectroscopy combined with density functional theory (DFT) and potential energy distribution (PED) analysis to identify the hierarchical structures of oligopeptides. The characteristic THz spectra of silk fibroin oligopeptides have been measured. Supported by DFT and PED analysis, the intrinsic differences among the dipeptides were identified by the collective vibrational modes of "R" groups and terminal groups linked by molecular chains of amido bonds or benzene rings. For tetrapeptides and hexapeptides, a few weak resonances and intensity differences were distinguished by the vibration mode of the molecular collective network formed by the interaction of amide planes and intramolecular hydrogen bond interactions. According to the THz absorption analyses of amide planes and intramolecular interactions within the molecular chains of silk fibroin oligopeptide isomer pairs, the formation and hierarchical structures were successfully interpreted using THz spectroscopy. This investigation develops a better understanding of the peptide formation mechanism, which further provides guidance in interpreting the formation of silk.

The compensatory mechanisms for global sagittal balance in degenerative spinal kyphosis patients: a radiological analysis of muscle-skeletal associations.

BACKGROUND: The position of the head relative to the spine can be used to evaluate the true global balance in patients with degenerative spinal kyphosis (DSK). However, it is still not clear how the position of the head is related to the spinal-pelvic parameters and lumbar muscles, which are most commonly considered. METHODS: Sixty-seven patients with DSK admitted in the hospital from January 2017 to January 2019 were retrospectively analyzed. All patients had whole spine X-ray and lumbar MRI. The head position parameters include: the angles of both lines joining the center of acoustic meati (CAM) to the center of the bi-coxofemoral axis (BA) (CAM-BA) and the most superior point of dentiform apophyse of C2 odontoid (OD) to BA (OD-BA) with the vertical line; the distance between the vertical line passing CAM and the posterior upper edge of the S1 (CAM-SVA). The spinal parameters include: C7 sagittal vertical axis (C7-SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), and lumbar lordosis (LL). The pelvic parameters include: pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). The relative cross-sectional area (RCSA) of bilateral multifidus, erector spinae and psoas muscle at L3/4 and L4/5 segments were measured. The correlations between head position parameters and the spinal-pelvic parameters and RCSA of lumbar muscles were analyzed, respectively. RESULTS: Significant positive correlations were found between each two of CAM-SVA, C7-SVA, CAM-BA and OD-BA (p < 0.001). SS was found to be significantly positively correlated with CAM-BA (r = 0.377, p = 0.034) and OD-BA (r = 0.402, p = 0.023). CAM-BA was found to be significantly negatively correlated with TK (r = - 0.367, p = 0.039). Significant positive correlations were found between RCSA of multifidus at L3/4 level and CAM-SVA (r = 0.413, p = 0.021), CAM-BA (r = 0.412, p = 0.019) and OD-BA (r = 0.366, p = 0.04). CONCLUSIONS: Our study showed that the head position relative to the spine were significantly correlated to some spinal-pelvic parameters, and the lower lumbar multifidus muscle. The compensatory mechanisms of the global sagittal balance status should also involve the head position area.

Risk prediction of degenerative scoliosis combined with lumbar spinal stenosis in patients with rheumatoid arthritis: a case-control study.

The purpose of this study is to compare incidence of degenerative scoliosis (DS) in patients who diagnosed lumbar spinal stenosis (LSS) with or without rheumatoid arthritis (RA) and identify the risk factors of DS severity in RA patients. 61 LSS patients with RA (RA group) and 87 demographic-matched LSS patients without RA (NoRA group) from January 2013 to April 2018 were enrolled. The extracted information includes RA-related parameters such as Steinbrocker classification, disease-modifying anti-rheumatic drugs (DMARDs), and DS-related information such as Cobb angle, apical vertebra, along with osteoporosis and history of total knee arthroplasty (TKA). Comparisons between RA and NoRA group and between DS and non-DS subgroup with RA were performed, as well as the risk factors on DS severity in RA patients. The incidence of DS in RA group was 42.6%, larger than that of NoRA group (P = 0.002). The mean Cobb angle between the two groups was of no difference (P = 0.076). The apical vertebrae were both mainly focused on L3 and L4 vertebrae in both groups with no significant difference on the distribution of apical vertebrae (P = 0.786). Female took a larger proportion in DS subgroup than that of NoDS subgroup in patients with RA (P = 0.039), while Steinbrocker classification was irrelevant to the occurrence of DS and Cobb angle. Multiple regression analysis showed that TKA was a risk factor for the severity of Cobb angle (P = 0.040). The incidence of DS in LSS patients with RA is higher than non-RA patients. RA patients performed TKA sustained less severity of DS.

Association between back muscle degeneration and spinal-pelvic parameters in patients with degenerative spinal kyphosis.

BACKGROUND: The paraspinal and psoas muscles have been considered to be essentially important for stabilizing the spinal column, and the muscle degeneration was found to exist in degenerative spinal kyphosis (DSK) patients. However, it is still not clear the relationship between muscle degeneration and spinal-pelvic alignment. The purpose of this study was to determine the correlations between the individual muscle degeneration at each lumbar spinal level and spinal-pelvic parameters in DSK patients. METHODS: The imaging data of 32 patients with DSK were retrospectively analyzed. The fat infiltration (FI) and relative cross-sectional area of muscle (RCSA) were quantitatively measured for multifidus (MF), erector spinae (ES) and psoas (PS) at each spinal level from L1/2 to L5/S1. The correlations were analyzed between RCSA and the sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI). RESULTS: The FI of MF and ES at L3/4, L4/5 and L5/S1 were higher than that at L1/2 and L2/3. The FI of PS at L4/5 and L5/S1 were lower than that of L1/2, L2/3 and L3/4. The RCSA of ES and PS from L1/2 to L5/S1 gradually increased, whereas the RCSA of ES from L1/2 to S5/S1 gradually decreased. The RCSA of MF at the L1/2 level was negatively correlated SVA (r = - 0.397,p = 0.024); the RCSA at L3/4, L4/5 and L5/S1 levels were negatively correlated with TK (r = - 0.364, p = 0.04; r = - 0.38, p = 0.032; r = - 0.432, p = 0.014); the RCSA at L4/5 level was positively correlated with LL (r = 0.528, p = 0.002). The RCSA of ES at L3/4 and L4/5 levels were positively correlated with PI (r = 0.377, p = 0.037) and SS (r = 0.420, p = 0.019). CONCLUSIONS: FI of MF and ES at lower lumbar level is higher than that at upper level, but FI of PS at upper lumbar level is higher than that at lower level. MF and ES have different roles for maintaining the sagittal spinal-pelvic balance.

House Dust Mite-Induced Allergic Airway Disease Is Independent of IgE and FcεRIα.

IgE contributes to disease exacerbations but not to baseline airway hyperresponsiveness (AHR) in human asthma. In rodent allergic airway disease (AAD), mast cell and IgE dependence for the induction of AHR has only been observed when mice are immunized with a relatively weak allergen without adjuvant. To evaluate the role of IgE in murine AAD that is induced by a potent allergen, we inoculated BALB/c and FVB/N background wild-type and IgE- or FcεRIα-deficient mice intratracheally with large or limiting doses of house dust mite extract (HDM) and evaluated AHR, pulmonary eosinophilia, goblet cell metaplasia, serum IgE, and lung mastocytosis. We found that neither IgE nor FcεRIα contributed to AAD, even in mice inoculated with the lowest dose of HDM, which readily induced detectable disease, but did not increase serum IgE or pulmonary mast cell levels. In contrast, high doses of HDM strikingly increased serum IgE and pulmonary mast cells, although both AHR and airway mast cell degranulation were equally elevated in wild-type and IgE-deficient mice. Surprisingly, allergen challenge of mice with severe AAD and pulmonary mastocytosis failed to acutely increase airway resistance, lung Newtonian resistance, or hysteresis. Overall, this study shows that, although mice may not reliably model acute asthma exacerbations, mechanisms that are IgE and FcεRIα independent are responsible for AHR and airway inflammation when low doses of a potent allergen are inhaled repetitively.

Fabrication of 14 different RNA nanoparticles for specific tumor targeting without accumulation in normal organs.

Due to structural flexibility, RNase sensitivity, and serum instability, RNA nanoparticles with concrete shapes for in vivo application remain challenging to construct. Here we report the construction of 14 RNA nanoparticles with solid shapes for targeting cancers specifically. These RNA nanoparticles were resistant to RNase degradation, stable in serum for >36 h, and stable in vivo after systemic injection. By applying RNA nanotechnology and exemplifying with these 14 RNA nanoparticles, we have established the technology and developed "toolkits" utilizing a variety of principles to construct RNA architectures with diverse shapes and angles. The structure elements of phi29 motor pRNA were utilized for fabrication of dimers, twins, trimers, triplets, tetramers, quadruplets, pentamers, hexamers, heptamers, and other higher-order oligomers, as well as branched diverse architectures via hand-in-hand, foot-to-foot, and arm-on-arm interactions. These novel RNA nanostructures harbor resourceful functionalities for numerous applications in nanotechnology and medicine. It was found that all incorporated functional modules, such as siRNA, ribozymes, aptamers, and other functionalities, folded correctly and functioned independently within the nanoparticles. The incorporation of all functionalities was achieved prior, but not subsequent, to the assembly of the RNA nanoparticles, thus ensuring the production of homogeneous therapeutic nanoparticles. More importantly, upon systemic injection, these RNA nanoparticles targeted cancer exclusively in vivo without accumulation in normal organs and tissues. These findings open a new territory for cancer targeting and treatment. The versatility and diversity in structure and function derived from one biological RNA molecule implies immense potential concealed within the RNA nanotechnology field.

Bone resorption during the first year after implantation of a single-segment dynamic interspinous stabilization device and its risk factors.

BACKGROUND: Dynamic interspinous stabilization devices generally provide satisfactory results, but can result in recurrent lumbar disc herniation, spinous process fracture, or bone resorption of the spinous process. The purpose of this study was to investigate if the Wallis dynamic stabilization device is associated with bone resorption. METHODS: Patients who underwent single-segment posterior lumbar decompression and implantation of a Wallis dynamic interspinous stabilization device at the L4/5 level between January 1, 2009 and October 1, 2011 were included. Bone resorption rate, Oswestry Disability Index (ODI), Japanese Orthopedic Association (JOA) score, and visual analogue scale (VAS) pain score were measured. Patient baseline and 1-year follow-up data were collected and analyzed. The bone resorption rate of the L4 and L5 spinous processes was calculated. RESULTS: Twenty four males and 20 females with a mean age of 42.7 ± 14.7 years were included. Twenty nine patients had significant bone resorption (bone resorption rate > 20%) and 15 had no bone resorption (bone resorption rate ≤ 20%) at 1 year after surgery. Lumbar lordosis ≥ 50° was associated with a lower bone resorption than lumbar lordosis < 50° and increasing BMI was associated with increased bone resorption. There were no significant differences between the bone resorption and no bone resorption groups in the improvement rate of VAS pain score, ODI, and JOA score at 1 year after surgery. CONCLUSIONS: Significant bone resorption occurs within 1 year after implantation of the Wallis device in more than 50% of patients. However, it does not affect short-term functional results.

Lack of Fas antagonism by Met in human fatty liver disease.

Hepatocytes in fatty livers are hypersensitive to apoptosis and undergo escalated apoptotic activity via death receptor-mediated pathways, particularly that of Fas-FasL, causing hepatic injury that can eventually proceed to cirrhosis and end-stage liver disease. Here we report that the hepatocyte growth factor receptor, Met, plays an important part in preventing Fas-mediated apoptosis of hepatocytes by sequestering Fas. We also show that Fas antagonism by Met is abrogated in human fatty liver disease (FLD). Through structure-function studies, we found that a YLGA amino-acid motif located near the extracellular N terminus of the Met alpha-subunit is necessary and sufficient to specifically bind the extracellular portion of Fas and to act as a potent FasL antagonist and inhibitor of Fas trimerization. Using mouse models of FLD, we show that synthetic YLGA peptide tempers hepatocyte apoptosis and liver damage and therefore has therapeutic potential.

[Efficacy of delayed administration of etanercept after spinal cord injury].

OBJECTIVE: To observe the effect of delayed administration of etanercept on the motor function, the expression of apoptosis-related genes and the pathological alterations of spinal cord in vivo in experimental murine model of spinal cord injury (SCI). METHODS: Seventy-two male adult SD rats were randomly divided into 6 groups, which were subjected to SCI induced by the application of vascular clips (force of 70 g) to the dura. Experimental groups (E1, E2, and E3 group) were given administration of etanercept immediately, 1 h, and 8 h after SCI. The control groups (C1, C2, and C3 group) were given administration of saline at the same time as experimental groups. Six rats of each group were killed 24 h after SCI in order to collect the samples for testing the expression of Bax and Bcl-2 by Western blot. The rest were killed 14 d after SCI for observing the pathological alteration using light microscopy. The recovery of motor function was graded using the modified murine Basso, Beattle, and Bresnahan (BBB). RESULTS: (1) The results of the expressions of Bax and Bcl-2 by Western blot: the gray value of the expression of Bax of E1 group was 165.423 ± 2.946, of E2 group 135.391 ± 3.045, of E3 group 108.543 ± 6.999, and of the control group 69.054 ± 0.774, and the gray value of the expression of Bcl-2 of E1 group was 58.854 ± 3.592, of E2 group 84.315 ± 2.138, of E3 group 125.091 ± 2.699, and of the control group 156.304 ± 2.490. (2) The results of BBB score: etanercept given immediately or 1 h after SCI could improve the recovery of the rats. There were significant differences in BBB score 14 d after SCI between E1 group (13.000 ± 1.095) and C1 group (7.167±0.753), E2 group (9.833 ± 1.472) and C2 group (7.000 ± 0.632) while there were no significant difference between E3 group (7.333 ± 0.516) and C3 group (6.833±0.753). (3) The result of histological alteration: histological alterations, such as necrosis, infiltration of lymphocytes and fibroblast and loss of nerve cells, were found attenuated in E1 and E2 groups, compared with C1 and C2 groups. There was no obvious difference between E3 and C3 groups. CONCLUSION: Administration of etanercept may inhibit the apoptosis after SCI, but this kind of effect may be too weak to improve the BBB score and histological alterations obviously when administration of etanercept is delayed 8 h after SCI. The clinical value of etanercept to SCI needs to be further validated.

[Establishment and validation of normal human L1-L5 lumbar three-dimensional finite element model].

OBJECTIVE: To create and validate a L1-L5 lumbar three-dimensional finite element model. METHODS: The L1-L5 lumbar spines of a male healthy volunteer were scanned with computed tomography (CT). And a L1-L5 lumbar three-dimensional finite element model was created with the aid of software packages of Mimics, Geomagic and Ansys. Then border conditions were set, unit type was determined, finite element mesh was divided and a model was established for loading and calculating. Average model stiffness under the conditions of flexion, extension, lateral bending and axial rotation was calculated and compared with the outcomes of former articles for validation. RESULTS: A normal human L1-L5 lumbar three-dimensional finite element model was established to include 459 340 elements and 661 938 nodes. After constraining the inferior endplate of L5 vertebral body, 500 kg × m × s⁻² compressive loading was imposed averagely on the superior endplate of L1 vertebral body. Then 10 kg × m² × s⁻² moment simulating flexion, extension, lateral bending and axial rotation were imposed on the superior endplate of L1 vertebral body. Eventually the average stiffness of all directions was calculated and it was similar to the outcomes of former articles. CONCLUSION: The L1-L5 lumbar three-dimensional finite element model is validated so that it may used with biomechanical simulation and analysis of normal or surgical models.

Incidence, prevalence, and causes of spinal injuries in China, 1990-2019: Findings from the Global Burden of Disease Study 2019.

BACKGROUND: Spinal injuries are an urgent public health priority; nevertheless, no China-wide studies of these injuries exist. This study measured the incidence, prevalence, causes, regional distribution, and annual trends of spinal injuries in China from 1990 to 2019. METHODS: We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 to estimate the incidence and prevalence of spinal injuries in China. The data of 33 provincial-level administrative regions (excluding Taiwan, China) provided by the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (CDC) were use to systematically analyze the provincial etiology, geographical distribution, and annual trends of spinal injuries. The Bayesian meta-regression tool DisMod-MR 2.1 was used to ensure the consistency among incidence, prevalence, and mortality rates in each case. RESULTS: From 1990 to 2019, the number of living patients with spinal injuries in China increased by 138.32%, from 2.14 million to 5.10 million, while the corresponding age-standardized prevalence increased from 0.20% (95% uncertainty interval [UI]: 0.18-0.21%) to 0.27% (95% UI: 0.26-0.29%). The incidence of spinal injuries in China increased by 89.91% (95% UI: 72.39-107.66%), and the prevalence increased by 98.20% (95% UI: 89.56-106.82%), both the most significant increases among the G20 countries; 71.00% of the increase could be explained by age-specific prevalence. In 2019, the incidence was 16.47 (95% UI: 12.08-22.00, per 100,000 population), and the prevalence was 358.30 (95% UI: 333.96-386.62, per 100,000 population). Based on the data of 33 provincial-level administrative regions provided by CDC, age-standardized incidence and prevalence were both highest in developed provinces in Eastern China. The primary causes were falls and road injuries; however, the prevalence and specific causes differed across provinces. CONCLUSIONS: In China, the overall disease burden of spinal injuries increased significantly during the past three decades but varied considerably according to geographical location. The primary causes were falls and road injuries; however, the prevalence and specific causes differed across provinces.

Burden of neck pain in general population of China, 1990-2019: An analysis for the Global Burden of Disease Study 2019.

Background: Neck pain has become very common in China and has greatly affected individuals, families, and society in general. In this study, we aimed to report on the rates and trends of the prevalence, incidence, and years lived with disability (YLDs) caused by neck pain in the general population of China from 1990 to 2019. Methods: We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) study to estimate the number and age standardised rates per 100 000 population of neck pain point prevalence, annual incidence, and YLDs in 33 provinces/municipalities/autonomous regions of China, stratified by age, sex, and sociodemographic index (SDI) from 1990 to 2019. We then compared these estimates with other G20 countries. Results: There were 6.80 × 107 patients with neck pain in 2019, presenting an increase from 3.79 × 107 in 1990. Likewise, the national age-standardised point prevalence increased slightly from 3.53% in 1990 to 3.57% in 2019. The YLDs increased by 78.08%, from 3814 × 103 in 1990 to 6792 × 103 in 2019. The age-standardised YLDs rate increased 1.50% from 352.84 in 1990 to 358.10 in 2019. The point prevalence of neck pain in 2019 was higher in females compared with males. These estimates were all above the global average level and increased more rapidly among G20 countries from 1990 to 2019. We generally observed a positive association between age-standardised YLD rates for neck pain and SDI, suggesting the burden is higher at higher sociodemographic indices. Conclusions: Neck pain is a serious public health problem in the general population in China, especially in its central and western regions, with an overall increasing trend in the last three decades. This is possibly related to changes of people's lifestyles and work patterns due to improvements in societal well-being and technology. Raising awareness of risk factors for neck pain in the general population and establishing effective preventive and treatment strategies could help reduce the future burden of neck disorders.

[Finite element analysis of lumbar fusion and Topping-off surgery].

OBJECTIVE: To evaluate the effect of Topping-off surgery on the adjacent segment of PLIF. METHODS: A finite element model of the human lumbar spine (L1-L5) was developed. The intact spinal model was validated by comparing it with previously reported models. Then, 2 models were analyzed and compared: (1) posterior lumbar interbody fusion (PLIF) at L4/5; (2) posterior lumbar interbody fusion at L4/5 and implantation of the interspinous spacer (ISP) at L3/4 (Topping-off). Then 500 N compressive loading plus 10 Nm moments simulating flexion, extension, lateral bending and axial rotation were imposed on both the L1 superior endplates. The ranges of motion, intradiscal pressures, facet stresses in L3/4, the stresses on spinous processes in L3 and L4 were investigated. All the measured data were analyzed by SPSS 21.0. RESULTS: The effect of the Topping-off on the adjacent segment appeared mainly in flexion-extension: the ranges of motion, intradiscal pressures (annulus and nucleus pulposus), both facet stresses were lower than that of the PLIF model, and the stresses on spinous processes in L3 and L4 were larger. Besides, the facet stresses on the left side in the left lateral bending were also lower than those of the PLIF model. CONCLUSION: Topping-off model is able to restrict the range of motion of the lumbar adjacent segment, decrease the intradiscal pressure and facet stresses, and has a potential effect of preventing adjacent segmental degeneration.

[Long-term clinical outcomes of selective segmental transforaminal lumbar interbody fusion and posterior spinal fusion for degenerative lumbar scoliosis].

OBJECTIVE: To explore the surgical techniques and long-term clinical outcomes of degenerative scoliosis (DS) with selective segmental transforaminal lumbar interbody fusion (TLIF) and posterior spinal fusion. METHODS: Ninety-five patients with adult degenerative lumbar scoliosis undergoing posterior long fusion at our department from January 1999 to December 2007 were analyzed retrospectively. The average follow-up period was 7.8 (5-13) years. The clinical outcomes of Oswestry disability index (ODI), visual analog scale (VAS), patient satisfaction and such radiographic parameters as Cobb angle, apical vertebra translation (AVT), Nash-Moe grade, lumbar lordosis (LL) and thoracolumbar kyphosis (TLK) were evaluated. RESULTS: The clinical outcomes of ODI score and VAS significantly improved at the last visit (P < 0.05). The ODI score was 32.2 ± 8.6 before surgery and 11.1 ± 6.8 at the last visit. The VAS was 8.9 ± 2.0 before surgery and 2.0 ± 1.2 at the last visit. Patient satisfaction was 88.2% (84/95) at the last visit. At the final evaluation, Cobb's angle, apical vertebra translation and Nash-Moe grades decreased with a statistically significant difference (P < 0.001) compared with preoperative parameters.Lordotic angle had a significant increase than preoperative angle (P < 0.001). Thoracolumbar kyphosis showed no significant change (P > 0.05). Besides, a significant positive correlation existed between the decrease of ODI score and the increment of lumbar lordotic angle (r = 0.62, P = 0.01) .Long-term complications included broken rod (n = 2), coronal junctional scoliosis (n = 4), L5-S1 spondylolisthesis (n = 2), L5-S1 restenosis (n = 5). And 11 patients underwent reoperation. CONCLUSION: A combination of selective segmental TLIF and posterior spinal fusion is both safe and effective for degenerative scoliosis and excellent long-term clinical outcomes may be achieved. And selective segmental TLIF can facilitate solid fusion, improvement of lumbar lordosis, better correction of lateral spondylolisthesis and asymmetric disc space so as to yield better corrective effects and long-term clinical outcomes.

[Effects of intrathecal injection of methylprednisolone sodium succinate in acute spinal cord injury rabbits].

OBJECTIVE: To investigate the effects and apoptosis of intrathecal injection of Methylprednisolone Sodium Succinate (MPss) for acute spinal cord injury (SCI) in New Zealand rabbits. METHODS: Seventy-two healthy New Zealand rabbits were used for the procedure and were randomly divided into two groups: SCI group and SHAM group, which was both divided into 6 subgroups, such as the vehicle group, the MPss intrathecal injection groups (1.5 mg/kg, 3.0 mg/kg, 6.0 mg/kg group), the MPss intravenous injection group and the combined injection group. TARLOV score was tested daily to evaluate the motor function. The rabbits were sacrificed 7 days after the surgery and the thoracic spinal cord sections and the sacral sections where MPss was injected were harvested for HE and TUNEL staining. Two-Factors Repeated Measures analysis of variance for TARLOV scores tested at various times and One-Way ANOVA analysis of variance for data between groups were used. RESULT: Seven days after surgery in SCI group, there was no statistical difference between the TARLOV scores of intrathecal injection of MPss 3.0 mg/kg group, 6.0 mg/kg group and MPss intravenous injection group (P > 0.05), which were all better than the vehicle group (F = 4.762, P < 0.05). Referring to the lymphocyte infiltration at the injury site in SCI group, there was statistical difference between MPss intrathecal injection 6.0 mg/kg group (1.33 ± 0.21) and the vehicle group (2.67 ± 0.21) (F = 5.793, P < 0.05) and no statistical difference between intrathecal injection of MPss 6.0 mg/kg group and MPss intravenous injection group (P > 0.05). As for the lymphocyte infiltration at the intrathecal injection site in SHAM group, there was statistical difference between MPss intrathecal injection 6.0 mg/kg group (2.50 ± 0.55) and the vehicle group (0.50 ± 0.55) (F = 17.333, P < 0.05). TUNEL staining in SCI group showed statistical difference between MPss intrathecal injection 6.0 mg/kg group (6.3 ± 1.5) and the vehicle group (20.3 ± 2.2) (F = 71.279, P < 0.05). CONCLUSIONS: Intrathecal injection of MPss can improve the functional recovery of lower limb and decrease apoptosis of neuron cells,which can provide same effects as the traditional intravenous injection of MPss in New Zealand rabbits.