OBJECTIVE: To analyze the current status and temporal trends of the disease burden of spinal fractures in China from 1990 to 2021 based on data from the Global Burden of Disease Study 2021 (GBD 2021), aiming to provide evidence for developing prevention and treatment strategies. METHODS: Epidemiological data on spinal fractures in China, the United States of America (USA), and globally were extracted from the GBD 2021 database. Joinpoint regression models were applied to analyze temporal trends. Age-standardized incidence, prevalence, and disability-adjusted life years (DALYs) rates were calculated, with comparisons of gender- and age-group disparities. RESULTS: In 2021, the number of incident cases, prevalent cases, and DALYs of spinal fractures in China increased by 52.28%, 113.68%, and 106.98%, respectively, compared to 1990. The age-standardized incidence, prevalence, and DALYs rates rose by 11.80%, 16.11%, and 14.79%, respectively. The disease burden escalated significantly with age, peaking in individuals aged ≥75 years. Males exhibited higher age-standardized incidence and DALYs rates than females. Comparative analysis revealed that the age-standardized DALYs rate in China (4.19/100 000) was lower than that in globally (6.62/100 000) and USA (15.92/100 000). However, China showed an upward trend [annual average percentage change (AAPC)=0.19%], contrasting with a declining trend in the USA (AAPC=-0.08%). CONCLUSION The escalating disease burden of spinal fractures in China is closely linked to population aging, gender disparities, and insufficient targeted prevention policies. Future strategies should integrate age- and gender-specific interventions, including strengthened osteoporosis prevention, trauma risk control, and big data-driven precision measures, to mitigate this burden.
Humans ; China/epidemiology* ; Global Burden of Disease/trends* ; Male ; Female ; Spinal Fractures/epidemiology* ; Middle Aged ; Aged ; Disability-Adjusted Life Years ; Prevalence ; Incidence ; Adult ; Young Adult ; Adolescent ; Aged, 80 and over ; United States/epidemiology* ; Cost of Illness ; Quality-Adjusted Life Years ; Child

Objective:To design an improved lamina hook system and compare its biomechanical properties with traditional lamina hook system in fixation of lumbar spondylolysis.Methods:The thin layer CT data of the lumbosacral vertebrae of 20 healthy young male servicemen who underwent physical examination in the outpatient department of the 940th Hospital of Joint Logistics Support Force of PLA from January 2021 to August 2022 were collected. The age of the subjects was 20-30 years [(25.0±3.0)years]. A 3-dimensional model of the L 5 vertebral body was constructed using the 3-dimensional modeling software. The new improved lamina hook was designed according to the measurements including the thickness of the middle area, the longest longitudinal diameter, the curvature radius of the lower edge, the angle between the upper and lower tail ends, the thickness of the lower edge, and the longest diameter of the lower edge of the bilateral L 5 vertebral plates. One serviceman was selected from the aforementioned group to construct a linear finite element model of segments L 4-S using the 3-dimensional virtual software (normal model, model A), based on which, the L 5 bilateral spondylolysis model (model B), improved lamina hook model (model C) and traditional lamina hook models (model D) were designed. By constraining both sides of the sacrum and applying a longitudinal load of 400 N on the L 4 vertebral body, the upper 1/3 gravity of the body was simulated, and with a bending moment of 10 N·m along the X, Y, and Z directions, motions of forward flexion, backward extension, lateral bending, rotation, etc were simulated. The range of motion of segment L 4/5 and L 5/S 1 of model A was evaluated and compared with the findings of the previous researches to verify its effectiveness. The overall range of motion of models A, B, C, and D, the range of motion of segment L 4/5 and L 5/S 1, the maximum overall displacement, the maximum displacement and stress of the isthmus, the stress distribution and maximum stress of internal fixation of models C and D, and the stress distribution and maximum stress of the vertebral body of models C and D were compared. Results:(1) During forward flexion, backward extension, lateral bending and rotation, the range of motion of model A was 5.01°, 4.03°, 3.91° and 1.42° in segment L 4/5, and was 4.62°, 2.51°, 2.40° and 1.23° in segment L 5/S 1. (2) The overall range of motion, range of motion of segment L 4/5 and L 5/S 1 and maximum overall displacement of models A, C, and D were similar in axial compression, forward flexion, backward extension, left bending, and left rotation, while those of model B were significantly increased. (3) There was no significant difference in the maximum displacement of the isthmus of models A, C, and D under different motion modes, while the maximum displacement of model B in the isthmus was significantly larger than that of models A, C, and D, especially during rotation, increased by 295%, 277%, and 276% respectively. The maximum stress of the isthmus of model C was 0.938 MPa, 1.698 MPa, 0.410 MPa, 2.775 MPa, and 1.554 MPa respectively. The maximum stress in the isthmus of model D was 0.590 MPa, 1.297 MPa, 0.520 MPa, 3.088 MPa, and 2.072 MPa respectively. The maximum stress of the isthmus of models C and D was similar during axial compression and forward flexion, while the stress of the isthmus of model C was smaller than that of model D during backward extension, lateral bending, and rotation, decreased by 21.1%, 10.2%, and 25.0% respectively compared with model D. (4) The maximum stress of internal fixation in models C and D during forward flexion, backward extension, left bending, and left rotation was 135.220 MPa, 130.180 MPa, 200.940 MPa and 306.340 MPa respectively, and was 131.840 MPa, 112.280 MPa, 349.980 MPa and 370.140 MPa respectively. The maximum stress of internal fixation in the two models of internal fixation during forward flexion and backward extension was similar, while it was decreased by 42.6% and 17.2% in model C during left bending and left rotation, compared with model D. (5) The maximum stress of the vertebral body during forward flexion, backward extension, left bending, and left rotation was 79.787 MPa, 36.857 MPa, 37.943 MPa and 96.965 MPa respectively in model C, but was 80.104 MPa, 64.236 MPa, 196.010 MPa and 193.020 MPa respectively in model D. The maximum stress of models C and D was all distributed in the contact area with the internal fixation, and especially during backward extension, left bending, and left rotation, when it was reduced by 42.6%, 80.6%, and 49.8% of model C respectively, compared with that of model D. Conclusions:The improved laminar hook is more consistent with the Chinese anatomized structure of the lamina. Compared with the traditional lamina hook system, the improved lamina hook system can effectively reduce the displacement in all directions and range of motion of lumbar spondylolysis, therefor can significantly reduce the stress of internal fixation and vertebral body and has better biomechanical performance.

An essential treatment for atlantoaxial dislocation is posterior atlantoaxial fusion. The current intra-articular fusion of the atlantoaxial lateral mass joint demonstrates a higher bone fusion rate, requires a smaller amount of bone graft, and has a lower incidence of complications. Although it has been employed in clinical practice, the atlantoaxial lateral mass intra-articular fusion cage is not yet widely utilized. Atlantoaxial instability and reducible atlantoaxial dislocation can be managed with simple posterior reduction, fixation, and atlantoaxial lateral mass intra-articular fusion. For patients with irreducible atlantoaxial dislocation, such as those with severe basilar invagination or obstructive anterior bone structures, transoral release is necessary, and anterior fusion cage placement is also feasible. Both posterior and anterior atlantoaxial lateral mass intra-articular fusion have seen significant improvements in surgical techniques, bone graft materials, and fusion cages. Among them, the procedure is evolving from the classic open approach to a more minimally invasive one. Bone graft materials include massive iliac bone, granular cancellous bone, fibula, autologous bone harvested from the C 1 posterior arch and C 2 lamina, and allogeneic bone, reflecting an increasingly diverse selection. Fusion cages have evolved from simple spacers to titanium blocks and further to cages that are anatomically adapted to the atlantoaxial joint, offering high bone fusion rates and various specifications of width and height. In anterior fusion cages, the circular design facilitates easy placement, while the wedge-shaped cage, when inserted transorally, better conforms to the physiological structure of the atlantoaxial lateral mass joint, resulting in improved surgical outcomes.The 3D-printed locking cage provides robust anterior support for fixation and fusion without the need for additional bone grafting. Anterior fusion cages are particularly suitable for patients with partial irreducible atlantoaxial dislocation requiring transoral release. Posterior cages, such as the cylindrical threaded cage, offer immediate stability. Customized cages exhibit more uniform stress distribution and can reduce cage subsidence. The posterior fusion cage has broad applicability and is suitable for patients with basilar invagination and atlantoaxial dislocation. The continuous advancements of fusion cages, bone graft materials, and surgical techniques will be from the aspects of stability, safety, and fusion rate to optimize the atlantoaxial lateral mass intra-articular fusion.

Objective:To explore the anatomical parameters of the ideal trajectory for pedicle screw fixation through the lamina in the treatment of L 5 spondylolysis. Methods:CT data from 40 male patients with bilateral L 5 spondylolysis (age, 24.95±4.01 years; range, 20-36 years), treated at the 940th Hospital of PLA Joint Logistics Support Force between January 2021 and June 2024, were analyzed. Three-dimensional vertebral models were reconstructed using this data. Measurements included the lumbosacral angle, the thickness at the midpoint of the superior and inferior lamina edges, mid-lamina thickness, the distance from the lateral edge of the lamina to the spinous process midline, the thickness at the defect of the pars interarticularis, and the vertical diameter of the defect. The screws were inserted from the inferior edge of the lamina, passing through the pars interarticularis defect, and exiting at the superior edge of the pedicle. In the vertical direction of the lamina, the inferior and superior edges of the lamina were divided into three zones, named A, B, C (for the inferior lamina edge) and 1, 2, 3 (for the superior pedicle edge). Seven trajectories (A2, A3, B1, B2, B3, C2, and C3) were designed by combining these zones. Screws with diameters of 5.0, 4.5, 4.0, and 3.5 mm were sequentially inserted along each trajectory. Screw trajectories with an insertion success rate ≥95% were selected and evaluated for feasibility. Parameters such as screw length, medial inclination angle, caudal inclination angle, and entry point position were measured. The ideal trajectory and screw dimensions were determined by considering anatomical features, screw characteristics, and insertion safety. Results:The measurement results from the 3D model showed that the lumbosacral angle was 36.22°±5.23°, and the midpoint thickness of the superior lamina edge was 4.14±0.66 mm (left) and 4.18±0.65 mm (right), the mid-lamina thickness was 6.73±0.72 mm (left) and 6.72±0.70 mm (right), the midpoint thickness of the inferior lamina edge was 6.50±0.56 mm (left) and 6.50±0.66 mm (right), the distance from the lateral edge of the lamina to the spinous process midline was 25.95±2.86 mm (left) and 26.39±3.10 mm (right), the thickness at the pars defect was 9.67±0.57 mm (left) and 9.67±0.51 mm (right), and the vertical diameter of the pars defect was 18.76±2.16 mm (left) and 19.26±2.03 mm (right). No statistically significant differences were found between the left and right sides for these parameters ( P>0.05). The trajectories considered feasible and with an insertion success rate ≥95% were B2, B3, C2, and C3. Safe screw diameters were B2 (4.5 mm), B3 (4.0 mm), C2 (4.0 mm), and C3 (3.5 mm). Corresponding screw lengths were B2 (38.28±2.34 mm), B3 (37.03±2.99 mm), C2 (38.37±2.42 mm), and C3 (36.88±2.87 mm). The caudal inclination angles were B2 (52.73°±5.29°), B3 (55.06°± 4.46°), C2 (49.09°±3.92°), and C3 (50.18°±4.36°). The medial inclination angles were B2 (21.21°±3.01°), B3 (5.11°±1.58°), C2 (22.55°±2.46°), and C3 (12.59°±1.80°). The distances from the entry point to the spinous process midline were B2 (13.23±1.68 mm), B3 (13.15±1.46 mm), C2 (11.12±0.64 mm), and C3 (11.09±0.65 mm). The distances from the entry point to the root of the spinous process were B2 (8.23±1.46 mm), B3 (8.21±1.31 mm), C2 (6.65 ±0.76 mm), and C3 (6.67±0.72 mm). Differences in screw length, caudal inclination angle, medial inclination angle, and entry point position across trajectories were statistically significant ( P<0.05). Conclusion:The ideal screw trajectory for L 5 spondylolysis involves insertion through the midpoint of the entry zone, passing through the pars defect, and exiting at the midpoint of the superior edge of the pedicle. The optimal entry point is located on the inferior edge of the lamina, 8.23±1.46 mm from the root of the spinous process and 13.23±1.68 mm from the spinous process midline. The screw should be placed at a caudal inclination angle of 52.73°±5.29° and a medial inclination angle of 21.21°±3.01°. The recommended screw length is 38.28±2.34 mm, with a diameter of 4.5 mm (range, 4.5-5.0 mm).

An essential treatment for atlantoaxial dislocation is posterior atlantoaxial fusion. The current intra-articular fusion of the atlantoaxial lateral mass joint demonstrates a higher bone fusion rate, requires a smaller amount of bone graft, and has a lower incidence of complications. Although it has been employed in clinical practice, the atlantoaxial lateral mass intra-articular fusion cage is not yet widely utilized. Atlantoaxial instability and reducible atlantoaxial dislocation can be managed with simple posterior reduction, fixation, and atlantoaxial lateral mass intra-articular fusion. For patients with irreducible atlantoaxial dislocation, such as those with severe basilar invagination or obstructive anterior bone structures, transoral release is necessary, and anterior fusion cage placement is also feasible. Both posterior and anterior atlantoaxial lateral mass intra-articular fusion have seen significant improvements in surgical techniques, bone graft materials, and fusion cages. Among them, the procedure is evolving from the classic open approach to a more minimally invasive one. Bone graft materials include massive iliac bone, granular cancellous bone, fibula, autologous bone harvested from the C 1 posterior arch and C 2 lamina, and allogeneic bone, reflecting an increasingly diverse selection. Fusion cages have evolved from simple spacers to titanium blocks and further to cages that are anatomically adapted to the atlantoaxial joint, offering high bone fusion rates and various specifications of width and height. In anterior fusion cages, the circular design facilitates easy placement, while the wedge-shaped cage, when inserted transorally, better conforms to the physiological structure of the atlantoaxial lateral mass joint, resulting in improved surgical outcomes.The 3D-printed locking cage provides robust anterior support for fixation and fusion without the need for additional bone grafting. Anterior fusion cages are particularly suitable for patients with partial irreducible atlantoaxial dislocation requiring transoral release. Posterior cages, such as the cylindrical threaded cage, offer immediate stability. Customized cages exhibit more uniform stress distribution and can reduce cage subsidence. The posterior fusion cage has broad applicability and is suitable for patients with basilar invagination and atlantoaxial dislocation. The continuous advancements of fusion cages, bone graft materials, and surgical techniques will be from the aspects of stability, safety, and fusion rate to optimize the atlantoaxial lateral mass intra-articular fusion.

Objective:To explore the anatomical parameters of the ideal trajectory for pedicle screw fixation through the lamina in the treatment of L 5 spondylolysis. Methods:CT data from 40 male patients with bilateral L 5 spondylolysis (age, 24.95±4.01 years; range, 20-36 years), treated at the 940th Hospital of PLA Joint Logistics Support Force between January 2021 and June 2024, were analyzed. Three-dimensional vertebral models were reconstructed using this data. Measurements included the lumbosacral angle, the thickness at the midpoint of the superior and inferior lamina edges, mid-lamina thickness, the distance from the lateral edge of the lamina to the spinous process midline, the thickness at the defect of the pars interarticularis, and the vertical diameter of the defect. The screws were inserted from the inferior edge of the lamina, passing through the pars interarticularis defect, and exiting at the superior edge of the pedicle. In the vertical direction of the lamina, the inferior and superior edges of the lamina were divided into three zones, named A, B, C (for the inferior lamina edge) and 1, 2, 3 (for the superior pedicle edge). Seven trajectories (A2, A3, B1, B2, B3, C2, and C3) were designed by combining these zones. Screws with diameters of 5.0, 4.5, 4.0, and 3.5 mm were sequentially inserted along each trajectory. Screw trajectories with an insertion success rate ≥95% were selected and evaluated for feasibility. Parameters such as screw length, medial inclination angle, caudal inclination angle, and entry point position were measured. The ideal trajectory and screw dimensions were determined by considering anatomical features, screw characteristics, and insertion safety. Results:The measurement results from the 3D model showed that the lumbosacral angle was 36.22°±5.23°, and the midpoint thickness of the superior lamina edge was 4.14±0.66 mm (left) and 4.18±0.65 mm (right), the mid-lamina thickness was 6.73±0.72 mm (left) and 6.72±0.70 mm (right), the midpoint thickness of the inferior lamina edge was 6.50±0.56 mm (left) and 6.50±0.66 mm (right), the distance from the lateral edge of the lamina to the spinous process midline was 25.95±2.86 mm (left) and 26.39±3.10 mm (right), the thickness at the pars defect was 9.67±0.57 mm (left) and 9.67±0.51 mm (right), and the vertical diameter of the pars defect was 18.76±2.16 mm (left) and 19.26±2.03 mm (right). No statistically significant differences were found between the left and right sides for these parameters ( P>0.05). The trajectories considered feasible and with an insertion success rate ≥95% were B2, B3, C2, and C3. Safe screw diameters were B2 (4.5 mm), B3 (4.0 mm), C2 (4.0 mm), and C3 (3.5 mm). Corresponding screw lengths were B2 (38.28±2.34 mm), B3 (37.03±2.99 mm), C2 (38.37±2.42 mm), and C3 (36.88±2.87 mm). The caudal inclination angles were B2 (52.73°±5.29°), B3 (55.06°± 4.46°), C2 (49.09°±3.92°), and C3 (50.18°±4.36°). The medial inclination angles were B2 (21.21°±3.01°), B3 (5.11°±1.58°), C2 (22.55°±2.46°), and C3 (12.59°±1.80°). The distances from the entry point to the spinous process midline were B2 (13.23±1.68 mm), B3 (13.15±1.46 mm), C2 (11.12±0.64 mm), and C3 (11.09±0.65 mm). The distances from the entry point to the root of the spinous process were B2 (8.23±1.46 mm), B3 (8.21±1.31 mm), C2 (6.65 ±0.76 mm), and C3 (6.67±0.72 mm). Differences in screw length, caudal inclination angle, medial inclination angle, and entry point position across trajectories were statistically significant ( P<0.05). Conclusion:The ideal screw trajectory for L 5 spondylolysis involves insertion through the midpoint of the entry zone, passing through the pars defect, and exiting at the midpoint of the superior edge of the pedicle. The optimal entry point is located on the inferior edge of the lamina, 8.23±1.46 mm from the root of the spinous process and 13.23±1.68 mm from the spinous process midline. The screw should be placed at a caudal inclination angle of 52.73°±5.29° and a medial inclination angle of 21.21°±3.01°. The recommended screw length is 38.28±2.34 mm, with a diameter of 4.5 mm (range, 4.5-5.0 mm).

Mass spectrometry imaging (MSI), a label-free molecular imaging technique, has been applied widely in the spatial localization of small molecule metabolites, lipids, peptides, and proteins, with its unique advantage of high spatial resolving power compared to traditional liquid chromatography-mass spectrometry (LC-MS).With the nonstop advancement of its achievable sensitivity and spatial resolution, MSI technique has been providing novel perspectives into the preclinical studies of drugs, such as in vivo localization of drugs and their metabolites, visualization of drug metabolism, and drug delivery tracking.This review introduces the basics of MSI techniques, including basic principles, key features, technical advantages, and limitations, with particular highlight of the recent applications of MSI in drug efficacy and safety evaluation, drug distribution research, drug delivery research, and analysis of Chinese medicine from recent publications, aiming to promote the utilization and further expansion of MSI in the research and development of drugs.

Lumbar spondylolysis is one of the common diseases of low back pain caused by spinal surgery. Its treatment options vary depending on different conditions, from early conservative ones to late surgical ones. There are still disputes over various conservative treatments, choice of surgical methods and the biomechanics of different internal fixation techniques to repair spondylolysis. Therefore, this review summarizes the clinical outcomes of previous clinical treatments of lumbar spondylolysis and the biomechanical characteristics of various techniques to find the mechanical and evidence-based clinical data that may facilitate the treatment of lumbar spondylolysis.

Objective To evaluate the outcome of posterior screw-rod fixation system in reduction and internal fixation of atlantoaxial dislocation. Methods A retrospective study was done on 27 patients with atlantoaxial instability including 18 male and 9 female (at age range of 13-51 years, mean 31 years) from January 2007 to May 2009. There were 11 patients with chronic odontoid fractures, five with isolated bone odontoid, seven with transverse ligament rupture of atlas and four with rheumatoid arthritis. Skeletal reduction was performed in all the patients. The anterior atlantodens interval (ADI)ranged from 8 mm to 15 mm, average 11 mm. All the patients underwent an intraoperative reduction by posterior C1 lateral mass and C2 pedicle screws with rod fixation. According to American Spine Injury Association (ASIA) impairment scale, there were eight patients at grade B, 15 at grade C and four at grade D. Results All patients were followed up for 6-24 months (average 13 months), which showed that the neck symptoms were improved, with bony union. The ADI was reduced to 2-4 mm (average 2.8 mm)postoperatively. Postoperative ASIA scale was grade C in four patients, grade D in 12 and grade E in 11.There were no neurologic or vascular complications occurred, or no failure of the internal fixtors, pseudarthrosis or instability. Conclusion Posterior screw-rod fixation system has advantages of simple procedures, few complications and good results and can be used for intraoperative reduction of atlantoaxial dislocation.