Objectives:To investigate the clinical efficacy of occipitocervical fusion with the occipital screw-rod-multiaxial screw internal fixation system in treating"sandwich"deformity with atlantoaxial disloca tion.Methods:A retrospective analysis was conducted on 62 patients who underwent posterior reduction,bone graft fusion,and occipitocervical internal fixation for"sandwich"deformity with atlantoaxial dislocation from January 2017 to January 2023.There were 19 males and 43 females,aged 51.1±23.5 years(29-72 years).The patients were divided into two groups based on the different fixation methods of the occipital screws used in the two types of occipitocervical internal fixation systems:group A of 38 patients utilized the occipital screw-rod-multiaxial screw system,consisting of 12 males and 26 females,aged 50.9±24.8 years(29-72 years),and the imaging findings revealed brainstem or cervical spinal cord compression in 30 cases,syringomyelia in 6 cases,and Chiari malformation in 2 cases;And group B of 24 cases utilized the occipital plate-rod-multiaxial screw system,consisting of 7 males and 17 females,aged 51.4±22.4 years(32-69 years),and the imaging findings revealed brainstem or cervical spinal cord compression in 16 cases,syringomyelia in 6 cases,and Chiari malformation in 2 cases.Group A was followed up for 36.5±11.8 months and Group B was followed up for 36.1±9.8 months.No statistically significant differences were observed between the two groups in terms of age,sex,imaging findings,or surgery style(P＞0.05).A comparison was performed between the groups regarding intraoperative blood loss,operative time,follow-up period,and complication rates.Clini-cal outcomes were evaluated preoperatively and at the final follow-up using the neck pain visual analog scale(VAS)score,neck disability index(NDI),and Japanese Orthopaedic Association(JOA)score.The cross-sectional and sagittal bone fusion area of the graft site,atlantodental interval(ADI),space available for cord(SAC),clivus canal angle(CCA),and cervico-medullary angle(CMA)were measured preoperatively,1 week postoperatively,and at the final follow-up in both groups.Results:Group A and group B weren't significantly different in intraoperative blood loss(362.4±89.1mL vs 345.1±93.8mL,P＞0.05)and operative time(144.8±35.6min vs 143.7±36.2min,P＞0.05).In group B,rod fractures occurred in 2 cases and loss of reduction was observed in 3 cases,whereas the remaining patients maintained stable screw-rod fixation.Neither group experienced severe complications such as spinal cord injury or cerebrospinal fluid leakage.Both groups demonstrated statistically significant differences between preoperative NDI,VAS,JOA scores and those measured at the final follow-up(P＜0.05),while no statistically significant differences existed between the two groups at the same time points(P＞0.05).Statistically significant differences were observed between preoperative and postoperative(1-week and final follow-up)measurements for ADI,SAC,CCA and CMA in both groups(P＜0.05),while no significant in-tergroup differences were found at corresponding time points(P＞0.05).In group A,the cross-sectional area and the sagittal area of the graft site were 385.44±84.51mm2 and 290.28±1 10.41mm2 in postoperative 1 week,and 267.06±66.13mm2 and 204.54±83.85mm2 at the final follow-up;which in group B were 442.61±76.85mm2 and 267.21±104.63mm2 in postoperative 1 week,and 172.43±37.37mm2 and 124.87±48.10mm2 at final follow-up.Comparisons between groups revealed no statistically significant differences in either cross-sectional or sagittal graft areas at 1 week postoperatively(P＞0.05),however,significant differences were observed at the final fol-low-up(P＜0.05)for both parameters between the two groups.Conclusions:The occipital screw-rod-multiaxial screw internal fixation system presents comparable restoration effects to the occipital plate-rod-multiaxial screw system in treating"sandwich"deformity with atlantoaxial dislocation.It exhibits satisfactory implant fusion postoperatively and achieves reliable occipitocervical fixation.

Cervical spinal cord injury without fracture-dislocation (CSCIWFD) is referred to as a special type of cervical spinal cord injury characterized by traumatic spinal cord dysfunction and no significant bony structural abnormalities on imagines. Duo to the high risk of missed diagnosis during the initial consultation, CSCIWFD may lead to progressive neurological deterioration or even complete paralysis, severely impacting patients′ prognosis. Currently, there are no established consensuses over the diagnosis and treatment of CSCIWFD, such as the lack of evidence-based standards for indications of non-surgical treatment and risk of secondary neurological injury, as well as debates over the optimal timing for surgical intervention and indications for different surgical approaches. To address these issues, the Spine Trauma Group of the Orthopedic Branch of the Chinese Medical Doctor Association organized experts in the relevant fields to formulate Diagnosis and treatment guideline for acute cervical spinal cord injury without fracture- dislocation in adults ( version 2025) . Based on evidence-based medicine and the principles of scientific rigor and clinical applicability, the guidelines proposed 11 recommendations covering terminology, diagnosis, evaluation treatment, and rehabilitation, etc., aiming to standardize the management of CSCIWFD.

Objective:To compare the efficacy of robot system-assisted versus freehand screw revision for ankylosing spondylitis (AS) with lower cervical fractures.Methods:A multicenter retrospective cohort study was conducted to analyze the clinical data of 57 patients with AS combined with lower cervical fractures admitted to Honghui Hospital Affiliated to Xi'an Jiaotong University School of Medicine, Henan Provincial People's Hospital, Zhengzhou Orthopedic Hospital, and Qilu Hospital of Shandong University, including 46 males and 11 females, aged 38-77 years [(65.4±9.5)years]. Injury segments involved C 3 in 7 patients, C 4 in 13, C 5 in 25, C 6 in 10, and C 7 in 2. All the patients underwent revision surgery, among whom, 22 patients were treated with robot system-assisted cervical pedicle screw placement (robot nailing group, with 190 screws), and 35 with freehand cervical pedicle screw placement (freehand nailing group, with 300 screws). The operative duration, intraoperative bleeding volume, frequency of intraoperative fluoroscopy, incision length, and length of hospital stay of the two groups were compared; the time of single nscrew insertion, the number of single nail revisions, the distance between screws and the anterior cortex, the accuracy of screw placement of grade 0 and grade 0+1 were recorded in the two groups. The visual analogue scale (VAS), Japanese Orthopedic Society (JOA) score, neck dysfunction index (NDI), American Spine Injury Association (ASIA) classification before operation, at 3 days, 3 months after operation and at the last follow-up were compared between the two groups. The complication rate was also noted. Results:All the patients were followed up for 12-16 months [(14.3±2.1)months]. The operative duration, intraoperative bleeding volume, and frequency of intraoperative fluoroscopy were (186.4±12.9)minutes, (486.1±68.6)ml, and (3.4±1.3)times in the robot nailing group, which were shorter or less than (206.7±14.4)minutes, (660.3±45.2)ml, and (13.5±3.6)times in the freehand nailing group ( P<0.01). The incision length was (9.4±2.4)cm in the robot nailing group, longer than (5.6±1.2)cm in the freehand nailing group ( P<0.01), and the length of hospital stay was (3.7±0.4)days, shorter than (4.4±1.4)days in the freehand nailing group ( P<0.01). The length of single nail insertion, the number of single nail revision, and the distance between the screws and the front cortex were (6.5±0.4)minutes, (1.1±0.1)times, and (3.5±1.3)mm in the robot nailing group, which were shorter or less than (11.6±0.2)minutes, (1.5±0.2)times, and (12.4±4.7)mm in the freehand nailing group ( P<0.01). The accuracy of the screw placement in the robot nailing group was 90.0% (171/190) and 95.8% (182/190) with level 0 and 0+1 screws, better than 80.0% (240/300) and 89.0% (267/300) in the freehand nailing group ( P<0.05). There was no significant difference in VAS, JOA score, NDI, or ASIA grading between the two groups before operation ( P>0.05). The VAS, JOA, and NDI scores at 3 days after operation were (3.1±0.6)points, (12.1±1.2)points, and (15.6±2.9)points, respectively in the robot nailing group, which were better than (5.0±1.4)points, (11.3±1.1)points and (22.5±3.7)points, respectively in the freehand nailing group ( P<0.05). No statistically significant difference was observed in the ASIA grade between the two groups at 3 days after operation ( P>0.05). There were no significant differences in VAS, JOA, NDI scores, or ASIA grading between the two groups at 3 months after operation and at the last follow-up ( P>0.05). Compared with those before operation, the VAS, JOA, NDI scores, and ASIA grading were significantly improved at 3 days, 3 months after operation and at the last follow-up in the two groups, which were further improved with the passage of time. Two patients in the robot nailing group had pneumonia, with a complication rate of 9% (2/22), while 2 patients in the freehand nailing group had dural sac rupture and cerebrospinal fluid leakage and 3 had lung infection after operation, with a complication rate of 14% (5/35) ( P<0.05). Conclusion:Compared with freehand nailing, the robot system-assisted nailing revision for AS with lower cervical fracture has more advantages in terms of the operative duration, length of hospital stay, intraoperative bleeding volume, frequency of intraoperative fluoroscopy nailing speed and accuracy, screw holding force, early pain relief, function restoration, and complication rate, despite longer surgical incision.

Objective:To compare the efficacy of laminoplasty via the intermuscular approach or posterior midline approach for treating spinal cord injury without radiographic abnormality (SCIWORA).Methods:A multi-center retrospective cohort study was conducted to analyze the clinical data of 135 patients with SCIWORA admitted to Honghui Hospital Affiliated to Xi'an Jiaotong University School of Medicine, Xi'an No.5 Hospital, Henan Provincial People's Hospital, Zhengzhou Orthopedic Hospital, Xuanwu Hospital of Capital Medical University from February 2021 to June 2023, including 75 males and 60 females, aged 35-78 years [(55.3±8.1)years]. The injury segments involved C 3-C 6. All the patients underwent posterior cervical open-door laminoplasty, among whom 70 patients were treated via the intermuscular approach (intermuscular group) and 65 via the posterior midline approach (posterior midline group). The operation duration, intraoperative blood loss, postoperative drainage volume, and length of hospital stay were recorded. The visual analogue scale (VAS) score, Japanese Orthopedic Association (JOA) score, neck disability index (NDI), Barthel index, cervical Cobb angle, and cervical range of motion (ROM) were measured preoperatively, at 3, 6, 12 months postoperatively and at the final follow-up. The American Spinal Injury Association (ASIA) scale was evaluated preoperatively, at 3, 12 months postoperatively and at the final follow-up. The postoperative complication rate was recorded as well. Results:All the patients were followed up for 15-19 months [(16.3±1.6)months]. The operation duration, intraoperative blood loss, postoperative drainage and length of hospital stay were (125.0±23.0)minutes, (210.4±34.8)ml, and (165.3±23.7)ml, and (5.3±0.1)days in the intermuscular group, which were significantly shorter or less than (168.0±27.6)minutes, (260.2±45.3)ml, (196.4±31.6)ml, and (6.4±0.2)days in the posterior midline group ( P<0.01). The preoperative VAS score, JOA score, NDI and Barthel index showed no significant differences between the two groups ( P>0.05). The VAS score and JOA score also showed no significant differences between the two groups at 3, 6, 12 months postoperatively or at the final follow-up ( P>0.05). The NDI and Barthel index also showed no significant differences between the two groups at 3 months postoperatively ( P>0.05). At 6, 12 months postoperatively and at the final follow-up, the NDI were (15.4±2.5)points, (11.8±2.1)points and (8.6±1.5)points in the intermuscular group, significantly lower than (19.1±3.4)points, (14.3±2.4)points and (11.9±1.4)points in the posterior midline group ( P<0.01). At 6, 12 months postoperatively and at the final follow-up, the Barthel index were (71.4±6.2)points, (83.4±5.8)points and (89.2±7.1)points in the intermuscular group, significantly higher than (59.6±4.7)points, (74.2±3.9)points and (78.8±6.2)points in the posterior midline group ( P<0.01). Both groups showed significant improvements in VAS score, JOA score, NDI and Barthel index at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05). Among them, the VAS score, NDI and Barthel index were further improved over time ( P<0.05). Simultaneously, the JOA score was significantly improved at 6, 12 months postoperatively and at the last follow-up when compared to that at 3 months postoperatively ( P<0.05), with no significant difference at later time points between the two groups ( P>0.05). The preoperative cervical Cobb angle and ROM showed no significant differences between the two groups ( P>0.05). There was no significant difference in the Cobb angle between the two groups at 3, 6 or 12 months postoperatively ( P>0.05), while it was (13.6±2.4)° in the intermuscular group at the final follow-up, significantly larger than (10.4±2.8)° in the posterior midline group ( P<0.01). At 3, 6, 12 months postoperatively and at the final follow-up, the cervical ROM were (34.1±6.4)°, (32.6±7.3)°, (31.8±9.1)° and (29.6±8.7)° in the intermuscular group, significantly larger than (23.7±8.3)°, (22.3±7.8)°, (22.5±8.1)° and (20.6±9.3)° in the posterior midline group ( P<0.01). In the intermuscular group, the cervical Cobb angle showed no significant changes at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P>0.05). In the posterior midline group, the Cobb angles were significantly reduced at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decrease at 12 months postoperatively and at the final follow-up from those at 3, 6 months postoperatively ( P<0.05), no significant difference at 6 months postoperatively from that at 3 months postoperatively ( P>0.05), and significant decrease at the final follow-up from that at 12 months postoperatively ( P>0.05). In the intermuscular group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively and showed further improvement over time ( P<0.05). In the posterior midline group, the cervical ROM were significantly improved at 3, 6, 12 months postoperatively and at the final follow-up when compared to those preoperatively ( P<0.05), showing significant decreases at 6, 12 months postoperatively and at the final follow-up from that at 3 months postoperatively ( P<0.05), significant decreases at the final follow-up from those at 6, 12 months postoperatively ( P<0.05), and no significant difference at 12 months postoperatively from that at 6 months postoperatively ( P>0.05). The ASIA grades showed no significant difference between the two groups preoperatively, at 3, 12 months postoperatively and at the final follow-up ( P>0.05) , but were gradually improved over time in both groups ( P<0.05). The postoperative complication rate was 9%(6/70) in the intermuscular group, significantly lower than 48%(31/65) in the posterior midline group ( P<0.01). Conclusion:Compared to the posterior midline approach, the intermuscular approach for laminoplasty in patients with SCIWORA possesses advantages, including shorter operative time and length of hospital stay, reduced intraoperative blood loss and postoperative drainage, less postoperative neck disability, higher daily life quality, better long-term preservation of cervical lordosis and motion, and a lower complication rate.

Vertebral refracture following percutaneous vertebral augmentation (PVA) is commonly seen in elderly patients with osteoporotic thoracolumbar compression fractures (OTLCF). It can lead to recurrent pain, loss of vertebral height, progression of kyphosis, and even neurological dysfunction, significantly impairing patients′ quality of life. Current diagnosis and treatment face multiple challenges, including high misdiagnosis rate, difficulty in choosing between surgical and non-surgical treatment options, lack of standardized surgical protocols, interference from intralesional bone cement during procedures, inadequate stability of internal fixation in osteoporotic bone, and suboptimal compliance of anti-osteoporotic therapy. Establishing a standardized diagnostic and therapeutic framework is urgently needed. To standardize the management process and improve outcomes for vertebral refractures after PVA in elderly OTLCF patients, Spinal Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized experts in the field to develop Guideline for the diagnosis and treatment of vertebral refracture after percutaneous vertebral augmentation in elderly patients with osteoporotic thoracolumbar compression fractures ( version 2025), based on current literature and clinical experience, and adhering to principles of scientific rigor and clinical applicability. A total of 11 recommendations were proposed, encompassing diagnosis, treatment, and rehabilitation of vertebral refracture after PVA in elderly patients with OTLCF, aiming to provide a foundation for a standardized management.

Thoracolumbar spine fracture often leads to severe pain, functional impairments, and neurological deficits, for which open reduction and internal fixation can effectively restore the spinal structural stability. Open decompression and reduction with internal fixation can help relieve spinal cord compression and improve spinal function in cases of concomitant cord injury. Although spinal stability can be restored through surgery, patients often face chronic pain and functional impairments postoperatively. A postoperative rehabilitation program is critical in optimizing therapeutic outcomes, reducing complications, and minimizing the risk of secondary injuries. However, current rehabilitation methods, such as physical therapy, functional training, and pain management, are confronted with problems in clinical practice, including significant variation in efficacy, poor patient adherence, and prolonged rehabilitation period. There is an urgent need for a unified rehabilitation strategy to address these problems. To this end, the Spinal Trauma Group of the Orthopedic Physicians Branch of the Chinese Medical Association and the Spine Health Professional Committee of the Chinese Human Health Technology Promotion Association organized experts from relevant fields to formulate Evidence-based guidelines for rehabilitation treatment after internal fixation of thoracolumbar spine fracture in adults ( version 2025) by integrating evidences from clinical researches and advanced rehabilitation concepts at home and abroad. A total number of 14 recommendations concerning the rehabilitation treatment with multimodal analgesia, psychological intervention, deep vein thrombosis prevention, core muscle and extremity exercise, appropriate use of braces, early weight-bearing, device-aided rehabilitation exercise, neuroregulatory therapy, rehabilitation team were put forward, aiming to standardize the post-operative rehabilitation process following internal fixation, promote the functional recovery, and enhance patients′ quality of life.

Acute symptomatic osteoporotic thoracolumbar compression fracture (ASOTLF) can lead to chronic low back pain, kyphosis deformity, pulmonary dysfunction, loss of mobility, and even life-threatening complications. Vertebral augmentation is currently the mainstream treatment method for this condition. In 2019, the Editorial Board of Chinese Journal of Trauma and the Spinal Trauma Group of Orthopedic Surgeons Branch of Chinese Medical Doctor Association collaboratively led the development of Clinical guideline for vertebral augmentation for acute symptomatic osteoporotic thoracolumbar compression fractures. Six years later, with advances in clinical diagnosis and treatment techniques as well as accumulating evidence in related fields, the 2019 guideline requires updating. To this end, the Spinal Trauma Group of Orthopedic Surgeons Branch of Chinese Medical Doctor Association, the Spinal Health Professional Committee of China Human Health Science and Technology Promotion Association, and the Minimally Invasive Orthopedics Professional Committee of Shaanxi Medical Doctor Association have organized experts in the field to develop the Clinical guideline for vertebral augmentation of acute symptomatic osteoporotic thoracolumbar compression fractures ( version 2025) , based on the latest evidence-based medical researches. This guideline incorporates 3 recommendations retained from the 2019 version with updated strength of evidence, along with 12 new recommendations. It provides recommendations from six aspects of diagnosis, pain management, treatment option selection, prevention of postoperative complications, anti-osteoporosis therapy, and postoperative rehabilitation, aiming to provide a reference for standard treatment of vertebral augmentation for ASOTLF in hospitals at all levels.

Objective:To investigate spinal cord morphological changes and risk factors in upper cervical spine surgery using C 2 medial "in-out-in" pedicle screws in patients with atlantoaxial dislocation (AAD) and high-riding vertebral artery (HRVA). Methods:A retrospective analysis was conducted on 41 patients with AAD who underwent C 2 medial "in-out-in" pedicle screw implantation at our hospital between January 2019 and December 2023. The cohort included 12 males and 29 females, with a mean age of 47.6±10.3 years (range: 18-68 years). Among them, 30 patients received unilateral C 2 medial "in-out-in" screws, while 11 patients received bilateral screws. All patients underwent posterior reduction and internal fixation. Measurements included C 2 pedicle height, C 2 pedicle width, C 2 horizontal spinal canal width, screw invasion distance into the spinal canal, and spinal canal invasion rate based on CT findings. MRI evaluations included spinal canal-dura mater distance, dura mater-spinal cord distance, spinal canal-spinal cord distance, and spinal cord cross-sectional area. The change rate of spinal cord cross-sectional area was calculated and categorized into >20% decrease group (decreasing group) and ≤20% decrease group (non-decreasing group). Postoperative outcomes were assessed using the Visual Analogue Scale (VAS) and Japanese Orthopedic Association (JOA) scores. Results:The mean operative time was 165.5±30.1 minutes (range: 120-220 minutes). No spinal cord vascular injuries or severe complications were observed. However, five patients experienced cerebrospinal fluid (CSF) leakage, requiring delayed removal of drainage tubes, but their wounds healed successfully. Follow-ups (range: 6-24 months) showed no loosening of internal fixation, fractures, or bone graft nonunion, with a 100% bone fusion rate at 6 months postoperatively. VAS scores improved significantly from a preoperative median of 5.0 (3.5, 6.0) (range: 1-7) to 2.0 (2.0, 3.0) at 3 months and 1.0 (1.0, 1.0) at 6 months ( Z=36.716, P< 0.001). JOA scores improved from 10.0 (9.0, 12.0) (range: 4-14) preoperatively to 13.0 (11.0, 13.5) at 3 months and 14.0 (12.0, 15.0) at 6 months ( Z=67.093, P<0.001). The height of C 2 pedicle was 5.50±1.78 mm, the width of C 2 pedicle was 2.27±1.23 mm, the width of C 2 horizontal spinal canal was 23.76±4.91 mm, the spinal canal-dura mater distance was 3.08±0.85 mm, dura mater-spinal cord distance was 3.23±0.85 mm, the spinal canal-spinal cord distance was 6.31±1.11 mm, the distance of screw invasion into the spinal canal was 2.80±1.54 mm, the rate of spinal canal invasion was 12.1%±6.8%, the preoperative spinal cord cross-sectional area was 69.81±13.27 mm 2, and the postoperative spinal cord cross-sectional area was 68.81±13.94 mm 2. Based on spinal cord cross-sectional area changes, 32 patients were classified into the non-decreasing group, and 9 patients into the decreasing group. The intraclass correlation coefficient (ICC) values ranged from 0.733 to 0.984, indicating high measurement reliability. There were significant differences in the proportion of C 2 bilateral medial "in-out-in" screws (χ 2=6.903, P=0.009), the incidence of CSF leakage (χ 2=15.391, P<0.001), the distance of screw invasion into the spinal canal ( t=4.990, P<0.001) and the rate of spinal canal invasion ( t=4.045, P<0.001) in the decreasing group versus the non-decreasing group. The JOA scores of the non-decreasing group were significantly higher at 3 and 6 months postoperatively compared to the decreasing group ( P<0.05). No other parameters showed significant differences between the groups. Binary logistic regression analysis identified spinal canal invasion rate [ OR=1.963, 95% CI (1.010, 3.817), P=0.047] as an independent risk factor for spinal cord cross-sectional area reduction. The Jordan index was 0.875, with a spinal canal invasion rate threshold of 14.18%, a sensitivity of 1.000, a specificity of 0.875, and an AUC of 0.983, indicating strong predictive value. Conclusion:The C 2 medial "in-out-in" screw technique provides effective posterior fixation and fusion for AAD patients with HRVA. However, to minimize spinal cord morphological changes and associated risks, the spinal canal invasion rate should be kept below 14.18% when using this technique.

Objective To clarify the biomechanical properties of oblique lumbar interbody fusion(OLIF)combined with lateral plate(LP)fixation under different bone conditions by means of finite element(FE)analysis,so as to provide mechanical basis for clinical practice.Methods The three-dimensional nonlinear L3_5 FE model of the spine was constructed.Different material properties were assigned to each part of the model to establish a model of normal bone(NB),osteopenia(OS)and osteoporosis(OP)of the lumbar spine.OLIF combined with the following three internal fixation models were established.For NB,there were OLIF alone(M0),OLIF+LP fixation(M1),and OLIF+bilateral pedicle screw(BPS)fixation(M2);for OS,there were OLIF alone(N0),OLIF+LP fixation(N1),and OLIF+BPS fixation(N2);for OP,there were OLIF alone(P0),OLIF+LP fixation(P1),and OLIF+BPS fixation(P2).A 500 N load was applied on the upper surface of L3 to represent the weight of the upper body,and a 7.5 N·m moment was used to simulate the vertebral motion under six different conditions:flexion(FL),extension(EX),left bending(LB),right bending(RB),left rotation(LR)and right rotation(RR).The range of motion(ROM)of the fixed segment of NB,OS and OP models was calculated,and the overall stress of the vertebral body,the stress of the cage and the internal fixation device were recorded.Results Compared with the complete model,the stability of each surgical model increased.Compared with M0,ROM of M1 decreased,especially in the LB and RB,which was roughly equivalent to the stability of BPS but weaker than BPS in the control FL and EX direction.The situation in OS and OP model was similar to that in NB.Under the same internal fixation,L4_5 ROM gradually increased with bone deterioration.The overall intervertebral ROM of N1 in the FL direction increased by 16.1％compared with M1,P1 in the FL direction increased by 32.1％compared with M1,and P1 in the FL direction increased by 19.0％compared with N1.With the increase of posterior internal fixation,the overall stress of vertebral body,Cage and internal fixation stress showed a downward trend.Under the same internal fixation,with the loss of bone mass,the overall stress of the model gradually increased.Compared with M0,P0 increased the most in LR,reaching 56.5％.In the NB and OS models,the peak stress of the LP fixation under FL exceeded the minimum yield strength of the material by 22.7％and 33.8％,respectively,and was less than the minimum fatigue strength and yield strength of the material under the rest of the motion.In the OP,the peak stress of the internal fixation exceeded the minimum fatigue strength of the material at FL and EX,and reached 53.3％(＞50％)at FL.Conclusions Under NB and OS,OLIF combined with LP fixation can significantly improve the stability of the surgical segment,especially in LB and RB directions,and the overall stability is weaker than that of BPS fixation.Under OP,FL and EX may increase the risk of internal fixation failure.Combination with BPS fixation should be considered to improve the safety of fixation.

Objective: To investigate the trends in disease burden due to childhood asthma in China from 1990 to 2021 and to project the disease burden from 2022 to 2035, so as to provide insights into formulation of the control interventions for childhood asthma in China. Methods: The prevalent case, agestandard prevalence, disability-adjusted life years (DALYs) and agestandard DALYs rate of children with asthma at ages of 0 to 14 years and their 95% uncertainty interval (UI) in China from 1990 to 2021 were extracted from the Global Burden of Disease (GBD) database. The temporal trends in the disease burden of childhood asthma were evaluated with estimated annual percentage change (EAPC) and its 95% confidence interval (CI), and the disease burden due to asthma was projected among children at ages of 0 to 14 years in China using a Bayesian age-period-cohort (BAPC) model from 2022 to 2035. Results: There were 9.368 3 million (95%UI=6.410 7 million to 14.026 1 million) prevalent cases of asthma among children at ages of 0 to 14 years in China in 2021, contributing to 0.387 9 million (95%UI=0.216 1 million to 0.668 8 million) DALYs loss. The prevalent cases and DALYs of asthma decreased by 37.28% and 52.55% among children at ages of 0 to 14 years in China in 2021 compared with 1990, and the agestandardized prevalence [EAPC=-0.70%, 95%CI=-1.26% to -0.13%)] and DALY rates [EAPC=-1.71%, 95%CI=-2.32% to -1.10%)] also appeared a tendency towards a decline. From 1990 to 2021, the prevalent cases, prevalence, DALYs and DALYs rate of asthma were all higher among male children than among female children, and the disease burden of asthma was higher among children at ages of 5 to 9 years than at other age groups. BAPC model predicted a decline in both prevalent cases and DALYs of asthma among children at ages of 0 to 14 years in China from 2022 to 2035, with 6.759 6 million prevalent cases and DALYs of 0.228 4 million personyears in 2035, while the prevalence and DALYs rates were projected to rise to 5 143.35/105 and 173.75/105 in 2035. Conclusions Despite a reduction in the disease burden of asthma among children at ages of 0 to 14 years in China from 1990 to 2021, the prevalence remained high. The disease burden due to asthma is projected to appear a decline among children at ages of 0 to 14 years in China from 2022 to 2035; however, the prevalence and DALYs rates still rise. Intensified control measures and targeted interventions are required to reduce the disease burden of childhood asthma.